Testing Steam Turbines: Conclusion
Abstract Generated abstract
This concluding section of a treatise on steam turbine testing sets out practical rules for conducting trials and recording measurements. It argues that tests should begin only after the turbine has reached a thermally steady state, indicated by stable condensate measurements and casing temperatures, and it specifies suitable reading intervals, test durations, thermometer handling, and accuracy precautions. The section also provides standardized log forms for recording turbine dimensions, steam pressures and temperatures, revolutions, steam consumption, load, brake measurements, and condenser operation, thereby contributing a systematic procedure intended to improve the reliability and comparability of turbine test results.
Full Text
Margerre with a Parsons turbine of 1450 h.p. ^133), Gutermuth with a Schultze turbine of 650 h.p. ^134), and Stodola with a Zoelly turbine of 2900 h.p. ^135).
Factory laboratories. In conclusion, let us list those admittedly very few and brief pieces of information which exist in the literature on special factory laboratories for testing steam turbines.
One of the earliest in time of publication is the testing station of the firm Richards, Westgarth & Co., Hartlepool, England ^136), which builds turbines of the Parsons system. Next comes Lasche’s article on the A.E.G. station in Berlin ^137). Some information and drawings are available concerning the testing station of the Vulcan works in Hamburg ^138). Finally, the last reports relate to the station of the firm John Brown, Clydebank, England ^139), which builds turbines of a modified Curtis system.
Chapter IX.
Conducting Tests.
46. Preparation of reports.—For the preparation of reports, three questions of time are of importance: when to begin the reports, i.e., the test itself; at what intervals to make the reports; and, finally, when to end them, i.e., how long the test should last.
The beginning of the reports should take place when a fully steady state of the entire turbine has been reached. Quite apart from the necessity of constancy of load, number of revolutions, pressure and temperature of the steam, one must first make sure that a steady state of the turbine has been attained in the thermal sense: that the heat loss to radiation has reached a constant value, and that all parts of the turbine have assumed a constant temperature, since, in addition to heat loss to heating, the elongation of parts and the sizes of clearances—both at the blades and at the various labyrinth seals—depend on this, i.e., the losses of steam through the corresponding leakages depend on it.
Reliable indicators of the establishment of a steady state in the thermal respect may be considered, first of all, the constancy of the amount of condensate obtained, measured over certain small intervals—
^133) Z. V. d. I. 1908, S. 1346.
^134) Z. V. d. I. 1910, S. 82.
^135) Z. V. d. I. 1911, S. 1709.
^136) Z. V. d. I. 1905, S. 2120; Engng. 80, 1905, p. 471.
^137) Z. V. d. I. 1909, S. 648.
^138) Engng. 90, 1910, p. 375, pl. XXIX.
^139) Engng. 90, 1910, p. 465, pl. XXXIX; Z. Turb. 1911, S. 284.
Chapter IX. Conducting Tests. § 46.
...of time, or, when using vessels with an outflow through Poncelet openings, the constancy of the condensate level in the vessel, and, secondly, the constancy of the temperature of certain parts of the turbine, e.g., the feet at the casing at both ends of the turbine or, if the cast-iron ribs at the horizontal joint plane of the casing are not covered with sheet metal, then the temperatures of these ribs near the steam inlet and the outlet from the turbine. The indicated temperature measurements are made by means of mercury thermometers with as fine divisions as possible: in the extreme case to \(1/2^\circ\), but preferably to \(1/5^\circ\) or even \(1/10^\circ\). The thermometer must be pressed as tightly as possible against the corresponding part of the cast-iron casting; for better heat transfer it is useful to wrap the bulb with mercury in tinfoil, and, for insulation from accidental movement of air, to cover it with cotton wool. To prevent the thermometer from accidentally falling, it is useful to fasten it carefully to the cast iron with threads or soft wire. In general it must be borne in mind that, in order to obtain a steady state, the turbine must operate under the given conditions for a sufficiently long time—an entire hour, and sometimes more.
The intervals between readings should, in order to obtain correct mean values, be as short as possible and, what is especially important, strictly identical. In general, in a steady state it is sufficient to take all the principal readings every 5 min., while auxiliary ones, such as, for example, readings of the temperature of the cooling water at the condenser or of its flow according to the water meter, may be taken even less often, every 10 min. In this, the readings of integrating instruments, such as the revolution counter or an instrument measuring the steam consumption by the quantity of condensate, must be taken with particular accuracy, down to 1 sec.; the others—for obtaining mean values, such as readings by the tachometer or by thermometers and manometers—may also be taken at less strictly identical intervals.
If the indications of the instruments fluctuate, for example in ammeters or wattmeters, then readings are also taken more often (every \(2\frac{1}{2}\), even 1 min.).
The duration of the test depends on how fully the requirement of a steady state is met, and on how carefully and accurately the readings are taken. In any case, the necessary duration of each turbine test is considerably less than for reciprocating steam engines. On average it may be considered that each test in which steam consumption is determined should last about 60 min.; with a fully established state and careful taking of readings, this duration may be reduced even to 30 min.; however, some testers increase the duration to 90 min., but along with this they limit themselves to tests lasting 60 and even 30 min.
Specimens of logs. Below, Tables 6–13, are given specimens of logs for the most common and important measurements. According to these speci-
§ 46. Production of reports.
... as well as according to the specimens indicated in footnotes \(^{113}\) to \(^{135}\), it is not difficult to compile journals also for other measurements or for other measuring instruments and devices. It must be said that the use of such journals, ruled in advance with a systematized order of reports, and, in frequent tests, the use of the corresponding printed forms, greatly facilitates the conduct of tests and increases their accuracy and the reliability of the results.
Table 6.
Journal No. 1
for the test of a steam turbine of the system .............................................................. of the plant ..............................................................
coupled with ................................................................................................................................................;
installed according to ....................................................................................................................................
the test was carried out ........................................................................ 191... yr. on ....................................
Principal data and dimensions:
Brief description of the system, indication of the method of regulation, and sketches with the principal dimensions of the working wheels and drum.
| No. | Item |
|---|---|
| 1 | nominal power of the turbine ........................................................................ \(d.\,l.\,s.\) or \(kW\). |
| 2 | normal number of revolutions per min. \(n\) ........................................................ |
| 3 | required steam pressure before admission \(p\) ................................................ kgf/cm.\(^2\) gauge. |
| 4 | required temperature ,, ,, \(t\) ........................................................ °C. |
| 5 | required vacuum in the condenser ........................................................ atm. abs. or %. |
| 6 | number of wheels in the active part, with indication of the number of rows of blades on each wheel ................................................................................................................................ |
| 7 | number of blades in each row ........................................................................ |
| 8 | diameters of the wheels together with the blades, in mm. ........................................ |
| 9 | lengths of the blades, in mm. ........................................................................ |
| 10 | sketches with dimensions of the blades and with inlet and outlet angles, or, if there are bands, corresponding impressions ................................................................................................ |
| 11 | number of stages at the drum of the reactive part, with indication of the number of rows of blades at each stage ................................................................................................ |
| 12 | number of blades in each row ........................................................................ |
| 13 | diameters of the drums without blades, in mm. .................................................... |
| 14 | lengths of the blades, in mm. ........................................................................ |
| 15 | sketches with dimensions of the blades and with inlet and outlet angles, or, if possible, take corresponding impressions ........................................................................................ |
| 16 | whether there are bands on the blades, and what their dimensions are .............................. |
| 17 | diameter of the steam-supply pipe, in mm. ........................................................ |
| 18 | diameter (dimensions) of the admission branch pipe, in mm. ...................................... |
| 19 | passage area in the narrow section of the first guiding apparatus (or nozzle) and their number ................................................................................................ |
| 20 | type of condenser, with principal dimensions ...................................................... |
| 21 | type of pumps for feeding water and air pumps, their principal dimensions and putting into operation ................................................................................................ |
Chapter IX. Conduct of Tests. § 46.
Table 7.
Log No. 2
for the test of a steam turbine of the system ................................................ of the works ................................................
of normal power at ................................................; ................................................ 191... year, at ................................................
the report was made by ....................................................................................................
Steam pressures and temperatures and in the room.
| time, h. min. | before the turbine, \(p\) atm. man. | before the turbine, \(t\) °C | behind the throttle valve, \(p_1\) atm. man. | behind the throttle valve, \(t_2\) °C | at exit from turb., \(h_0\) mm Hg | at exit from turb., \(t_0\) °C | barometer, \(B\) mm Hg | in the room, \(t_n\) °C | remarks |
|---|---|---|---|---|---|---|---|---|---|
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | Nos. of instruments, corrections that must be introduced according to calibration, etc.; rarefaction in %: \(\dfrac{100 h_0}{760}=\) |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | abs. press. \(\dfrac{B-h_0}{737.4}=\) .... kg/cm.\(^2\) |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | |
| average |
Table 8.
Log No. 3
for the test of a steam turbine of the system ................................................ of the works ................................................
of normal power at ................................................; ................................................ 191... year, at ................................................
the report was made by ....................................................................................................
Numbers of revolutions.
| time, h. min. | interval \(\Delta\tau\), min. | counter, \(\Sigma n\), revol. | difference, \(\Delta n\), revol. | \(n=\dfrac{\Delta n}{\Delta\tau}\), rev./min. | tachom. \(n'\), rev./min. | oil pressure \(p\), atm. man. | remarks |
|---|---|---|---|---|---|---|---|
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | position of the governor: ........ |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | average reading \(\dfrac{\Sigma \Delta n}{\Sigma \Delta \tau}=\) .... |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | |
| \(\Sigma\Delta\tau\)..... | \(\Sigma\Delta n\)..... | avg. |
Table 9.
Log No. 4
for the test of a steam turbine of the system _ of the _ works
of normal power of _; _ 191_. in _
the report was made by _____
Steam consumption by the turbine (with surface condenser).
| time, h. min. | difference $\Delta\tau$, min. | tank No. 1 — tare, kg | tank No. 1 — gross, kg | tank No. 1 — diff., kg | tank No. 2 — tare, kg | tank No. 2 — gross, kg | tank No. 2 — diff., kg | remarks |
|---|---|---|---|---|---|---|---|---|
| total | — | — | — | — |
Table 10.
Log No. 4 bis
for the test of a steam turbine of the system _ of the _ works
of normal power of _; _ 191_. in _
the report was made by _____
Steam consumption by the turbine (with surface condenser).
| time, h. min. | diff. $\Delta\tau$, min. | water temp. $t$, °C | height over the Poncel. $h$, mm. | difference $\Delta h$, mm. | $G$ according to eq. (571), kg/hour | remarks |
|---|---|---|---|---|---|---|
| orifice area of the Poncel $f\ \mathrm{m}^2$ _ cross-sectional area of the vessel $F\ \mathrm{m}^2$ _ |
||||||
| 1) $G=3600000\left(\mu f\sqrt{2gh}+F\frac{\Delta h}{\Delta\tau}\right)=$ ____ | ||||||
| 2) mean height. $h_c=\left(\dfrac{2\sqrt{h_i}}{i}\right)^2=$ ____ | ||||||
| duration | mean | mean$^{2)}$ | $\Sigma\Delta h$ | mean$^{3)}$ | 3) hourly$^{1)}$ consumption may also be calculated at once: $G=3600000\left(\mu f\sqrt{2gh_i}+F\frac{\Sigma\Delta h}{\Delta\tau}\right)=$ ____ |
Chapter IX. Conduct of Tests. § 46.
Table 11.
Log No. 5
for the test of a steam turbine, system ................................................ plant ................................................
normal power in ........................................ kW; ........................................ 191 yr. on ........................................
the report was made by ....................................................................................................
Turbine load.
| time | volts | amperes | $\cos\varphi$ | kW | excitation | excitation | excitation | remarks |
|---|---|---|---|---|---|---|---|---|
| h. min. | $A$ | $V$ | volts | amperes | kW | |||
| generator efficiency coefficient $\eta_2 =$ | ||||||||
| work on the turbine shaft $N_k =$ | ||||||||
| $= 0.001\, A \cdot V \cos\varphi \cdot \eta_2 =$ ........ | ||||||||
| average | what part of the normal load the given load constituted ........ |
Table 12.
Log No. 5 bis
for the test of a steam turbine, system ................................................ plant ................................................
normal power in ........................................ h.p. ........................................ 191 yr. on ........................................
the report was made by ....................................................................................................
Turbine load by water brake.
| time | height | load $G$ | water-meter reading | height | water temperature | water temperature | remarks |
|---|---|---|---|---|---|---|---|
| h. min. | mm | kg | liter | liter | inlet $t_1$ °C | outlet $t_2$ °C | |
| length of arm $L =$ ................ m. | |||||||
| from log No. 3 the average number of rev./min. $n =$ ................ | |||||||
| $N_e = 0.001396\, G.L.n =$ ................ h.p. | |||||||
| total: | total: | avg. | by water consumption $Q$ kg/hour, work $N_e = Q(t_2 - t_1):632.3 =$ ................ h.p. |
Table 13.
Log No. 6
for the test of a steam turbine of the system ........................................ plant ........................................
normal power in ........................................; ........................................ 191 in ........................................
the report was made ................................................................
Operation of the condenser.
| time | time | duration | water-meter reading | difference | water temperature | water temperature | energy consumption for the air pump | energy consumption for the air pump | notes |
|---|---|---|---|---|---|---|---|---|---|
| h. | min. | min. | ltr. | ltr. | inlet \(t_1^\circ\text{C}\) | outlet \(t_2^\circ\text{C}\) | volt. \(V\) | amp. \(A\) | notes |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | water consumption ........ kg/hour ........ |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | pump operation, at \(\cos\varphi =\) ........ and \(\eta_{\mathrm{e}}=\) ........ |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | \(L_{\mathrm{n}} = 0.001\,A\,V\cos\varphi\cdot\eta_{\mathrm{e}} =\) ........ kW. |
| ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | ........ | energy consumption equals \(0.001\,A\,V\cos\varphi =\) ........ kW. |
| total: ........ | total: ........ | total: ........ | total: ........ | total: ........ | av.: ........ | av.: ........ | ........ | ........ | ........ |
47. Processing of experimental material.—The processing of the raw numerical material obtained in testing a steam turbine may be divided into two stages: 1, the derivation of average values from all the entries made during the test, and 2, the calculation of quantities characterizing the given test, i.e., the turbine load and the steam consumption per 1 kW or 1 hp.
In more detailed tests of a scientific and technical character, a third stage should also be added: the determination of the influence on economy of various factors, such as the magnitude of superheat, vacuum, various design features, as well as the determination of the magnitude of the various losses and, finally, the calculation of the hydraulic efficiency \(\eta_{\mathrm{h}}\), both of the entire turbine and of the individual wheels and stages.
Finding average values. In calculating average values one should not fall into the error, often encountered even among the best authors, namely an excessive fondness for the number of decimal places. In calculating an arithmetic mean it is sufficient to take it to only one digit more than the terms. In calculating an average value obtained by multiplying or dividing arithmetic mean values, one should take only such a number of decimal places or, correspondingly, replace units—sometimes tens and hundreds as well—by zeros, so that the discarding of superfluous significant figures rounds the resulting number precisely within the limits of the accuracy of its determination in the corresponding experiments.
All multiplications and divisions may safely be carried out with the aid of the large scale of a 25 cm slide rule; for more exact tests it is useful to take a rule 50 cm long, or N. Nestler’s “precision” system rule, equal to it in accuracy.
Accuracy and its determination. As a measure of the accuracy of arithmetic means one may take the mean error \(m\) of the mean value, computed from the expression
\[ m=\pm\sqrt{\frac{\sum[\delta_n]^2}{n(n-1)}}, \tag{101} \]
where \(\sum[\delta_n]^2\) is the sum of the squares of the differences between the individual measurements and the mean value \(a\), and \(n\) is the number of measurements made.
The accuracy proper \(\nu\) is expressed in % of the mean value \(a\)
\[ \nu=\pm 100\,m/a. \tag{102} \]
If some measurement is not performed repeatedly, for example, marking with a stopwatch the instant of readings on a revolution totalizing counter, or marking the height of a barometer, then the error must be computed according to the corresponding possible deviation of the quantity \(a\) by an amount \(p\) from the true value, i.e.,
\[ \nu=\pm 100\,p/a. \tag{103} \]
If the quantity \(A\) is formed as the product or quotient of several quantities, then its mean error \(\nu'\) is equal to the sum of the \(\nu\)’s of the component quantities.
If the quantity \(A\) is obtained as the sum or difference of several quantities, then its mean error \(\nu''\) is computed from the expression
\[ \nu''=\pm\sqrt{\sum(\nu)^2}, \tag{104} \]
where the mean error \(\nu\), in %, of each separate quantity \(a\) must be determined from the mean absolute error \(m\) relative to the whole \(A\), i.e. in this case
\[ \nu=\pm 100m/A. \tag{105} \]
Such calculation of mean errors, first, gives an objective measure for evaluating tests and their results; further, it sometimes proves the impossibility of attaining special accuracy in determining one or another quantity, while at other times, on the contrary, it reveals a greater accuracy of some quantity than appears at first glance and, finally, is very useful in choosing the number of significant figures in the result.
In general, such calculation of the accuracy of individual quantities and of the whole result is practiced very rarely in technical measurements, but quite in vain: the corresponding calculations are in general not difficult, and they give interesting, sometimes quite unexpected, results.
Criticism and correction of records. In deriving mean values one should not confine oneself to a purely mechanical computation of aver-
§ 47. Criticism and Correction of Records.
... of arithmetic quantities for the corresponding reports, but rather one must treat them critically, i.e., when deriving mean quantities, carefully examine every recorded number and, if it is doubtful, either correct it, if possible, by using other records, or else strike it out altogether, if that is possible, or, finally, even reject and discard the entire given experiment, if the doubtful number is too important.
Of course, when deriving mean quantities, one should by no means fall into the other extreme as well: into an overly light attitude toward figures and a hasty replacement of some numbers by others. On the attentiveness, caution, and, one may say, special tact of the person who processes the raw numerical material, the value and accuracy of the final results of the tests depend to a significant degree.
As for the criticism of the records made and their correction, several cases are possible: the simplest, when there is a series of numbers which, generally speaking, should remain constant, such as, for example, the temperature of the water entering the refrigerator, or the flow rate of this same water per unit time. If, for example, this temperature stood all the time at 14.5°, and in one of the intermediate reports stands 18.5°, then, obviously, this is a slip which cannot be taken into account when calculating the mean value; the same must be said with regard to a sharp change in the flow rate of the water, provided only that the number of revolutions of the pump did not change during the test, and so forth.
The second case is when an error in some record can be checked by another record. Thus, for example, if the reading of the mercury vacuum gauge fluctuated between 690 and 694 mm, and in one report 660 mm is recorded, then one must look at the record of the steam temperature at the outlet; since the steam is usually wet, its temperature depends on the absolute pressure, and for a vacuum of 690–694 mm it is, at an average barometer height, about 36° C, while for 660 mm it is about 46° C; if the indicated increase by 10° is not present in the corresponding temperature record, then the vacuum record is incorrect, and for calculating the mean value it should not be taken into account.
Finally, the third case of correcting a record is when an error is detected only by means of more complex comparisons; thus, for example, if some quantity in itself does not give rise to doubt, but when graphically representing its dependence on some variable quantity—for example, on the pressure or temperature of superheated steam or on the load—there results not a smooth curve, but one with a break, or one point lies far above or below the otherwise smooth curve. Sometimes it is possible to clarify the error, but more often in these cases one has simply to discard the given test, or at least everything connected with the doubtful quantity.
Corrections from instruments. Above, in speaking of instruments, we indicated methods for checking them. Most even of good instruments require the introduction of corrections found experimentally during verification. One must not forget to introduce these corrections, but this may already be done to the mean values.
48. Steam consumption.—One of the chief questions, the answer to which is required from almost every test, is the magnitude of the steam consumption \(D\), in kg, per unit of work per unit of time.
As the unit of time in engineering it is customary to take 1 hr.; as regards the unit of work, matters are considerably less definite. First of all, it should be noted that in turbine construction two units of power have acquired equal rights of citizenship: the horsepower, equal to 75 kg·m/sec., and the kilowatt, equal to 102 kg·m/sec. In kW the power is expressed only for turbogenerators, of which, however, more are still being built than turbines coupled to other working machines. It should be noted here that often the power of a turbine coupled to an electric generator is also expressed in h.p.
Accordingly, the steam consumption is calculated either as \(D_e\) kg/h.p.-hr., or, for turbogenerators, also as \(D_k\) kg/kW-hr.
With regard to the calculation of the consumption \(D_k\), it must also be pointed out that up to now it has not been established to what work \(N_k\) kW it should be referred: whether to the total work at the shaft, including the consumption of energy for the exciter dynamo and for driving the electric motors connected with the condenser pumps; or to the work at the shaft, without adding the consumption of energy for excitation, but also without subtracting the consumption of energy for cooling; or, finally, to the actually useful energy at the switchboard, i.e., after subtracting the energy expended on cooling. The last method is, in practice, perhaps the most correct, since it takes into account the work of the whole unit as such. However, in a correct test, both of the indicated energy consumptions, for excitation and for cooling, must in any case be found and stated, and then making the corresponding recalculation of the value \(D_k\) presents no difficulty. The same should also be said with regard to the calculation of \(D_e\): the consumption of work for cooling may or may not be excluded from the work of the turbine; ordinarily it is not excluded. For a correct assessment of the economy of a turbine it is important, in calculating \(D_k\) or \(D_e\), to state to what work they have been referred. Only under this condition are valuable data obtained, permitting a correct comparison of different turbines with one another.
Incidentally, if at first the steam consumption \(D_k\), referred to 1 kW, has been calculated, and it is necessary to find the consumption \(D_e\) kg/h.p.-hr., then for this it is necessary to know the efficiency \(\eta_{\mathrm{э}}\) of the electric generator, and then
\[ D_e = 0{,}736 \cdot \eta \cdot D_k; \tag{106} \]
of course, the quantity \(D_k\) in this case must be calculated from the full power \(N_k\) kW, without subtracting the expenditure of energy for excitation and for cooling.
Reduction of the quantities \(D\). For a correct comparison of different turbines and of different tests of one and the same turbine, it is desirable to reduce the steam consumption to identical conditions of operation of the steam, i.e., to the same initial pressure \(p\), the same superheat temperature \(t\), if the steam is superheated, or the same steam content \(x\), if it is wet, and the same pressure \(p_0\) in the condenser.
As is known, the steam consumption \(D\) decreases with an increase of \(p\) and \(t\) or \(x\), and with a decrease of \(p_0\). This decrease in the quantity \(D\) depends on the totality of all three indicated quantities characterizing the conditions of operation of the steam, and also on the design and power of the turbine; therefore it is impossible to give general numerical data for recalculation, and one can only indicate average data for various most common special cases. However, below we shall indicate a method of more accurate recalculation by means of simple additional tests.
Initial pressure \(p\), according to information communicated by the Brown, Boveri & Co. works1, affects its Parsons-system turbines in the following way: at a power of about 200 kW, an increase of \(p\) by 1 atm gives a decrease of \(D\) by 1%; for turbines of greater power, an increase of \(p\) by 1 atm gives a decrease of \(D\) by 1.5–2.0%. According to Moyer’s data2, for an American turbine of 200 kW3, in all probability of the Curtis system, each 1 atm change in \(p\) gives a change in \(D\) of 3%; the same Moyer gives, for a Westinghouse-Parsons turbine of 7500 kW, respectively, a change in \(D\) of 1.4%4. Further, for a vertical Curtis turbine of 9000 kW, the works, on the basis of its own experiments, specified in the guarantee, for a 1 atm decrease of \(p\), an increase of \(D\) by 1.4%5. Finally, Stodola6 gives, for \(p\) from 10 to 15 atm, with operation with a condenser, for each 1 atm change in \(p\)—with saturated steam, a change of \(D\) by 1.7%, and with steam superheated to 300°—a change of \(D\) by 1.0%.
Superheat temperature \(t\). According to the data of Brown, Boveri & Co.1, raising the steam temperature \(t\) between 200° and 240° by each 10° gives a decrease of \(D\) by 1.8–2.0%; from 240° to 280° it gives 1.5%, and from 280° to 320° it gives 1.3%; however, according to other data of the same works7, for turbines of 3000 kW, for \(t\) from 220 to 300°, an increase by 10° gives—
Chapter IX. Production of Tests. § 48.
there is a decrease of \(D\) by 1.75%. According to Meyer’s data\(^{141}\), for the turbine of 200 kW indicated above, an increase of \(t\) by \(10^\circ\)C gives a decrease of 1.4%; Meyer gives the same figure for a 9000 kW Curtis turbine\(^{143}\), \(^{144}\); for the Westinghouse-Parsons turbine indicated above he gives a somewhat smaller value, namely 1.25%. For the Brown-Curtis turbine a decrease of \(D\) by 1.8% was found\(^{147}\). In Hütte\(^{148}\) average values of 1.4–2.0% are given. Finally, Stodola\(^{145}\) gives a value of 1.3%.
Moisture content of the steam \(x\). The comparatively rare operation of modern turbines without superheating explains the small number of numerical data on the influence of the steam content \(x\) on the steam consumption \(D\). Nevertheless, for the above-mentioned Brown-Curtis turbine it was found\(^{147}\) that for each 0.01 \(x\), \(D\) increases by 0.6%; Meyer\(^{143}\) gives for the Westinghouse-Parsons turbine the comparatively large value of 2.0%, explaining it by the considerable increase of drum resistance in wet steam containing droplets of water. Finally, Stodola gives the value 1.0%\(^{145}\).
Pressure in the condenser \(p_0\). According to the data of Brown, Boveri & Co.\(^{149}\), if the normal pressure is taken to be \(p=0.1\) kg/cm.\(^2\) abs., a decrease of it by 0.01 atm. gives a decrease of \(D\) by 2.0–3.0%, whereas an increase of \(p_0\) by 0.01 atm. gives an increase of \(D\) by 1.5%. According to Meyer’s data\(^{141}\), \(^{143}\), the corresponding corrections at pressure \(p_0=0.08\) amount to \(-1.0\%\) and \(+1.0\%\); according to his own data\(^{143}\) for various Parsons turbines this quantity ranges from 1.0–1.45–1.74%; according to Losse’s data\(^{149}\) for Parsons turbines the corresponding value is only 0.65%; at the same time, according to a communication from Parsons himself\(**\), the influence of vacuum is different for turbines of different power: for a 100 kW turbine, for 1% of vacuum, 0.9% of steam consumption; for 500 kW—1.2%, and for 1500 kW—1.6%; for one Curtis turbine of 9000 kW this value was 2.0%\(^{144}\); for another turbine of the same kind, 2.4%\(^{143}\); for Laval turbines about 1.2–1.5%\(^{150}\); according to Gerken’s data\(^{151}\), for Zoelly turbines the corresponding values at \(p_0=0.05\) are—when \(p_0\) is decreased by 0.01, about \(-2.0\%\), and when it is increased—about \(+1.0\%\). In Hütte\(^{148}\) average values are given for \(p_0=0.20–0.03\): a change of \(D\) by 1.0–3.0%; for turbines operating with wet steam, the case is still greater, i.e. approximately up to 4.0%. However, it is added there that the reduction of consumption \(D\) when \(p_0\) is lowered occurs only until the discharge velocity of the steam reaches the speed of sound, i.e. about 405 m/sec. This opinion is refuted by the tests of Lesel\(^{152}\), who found that, despite the fact that the veloc—
\(^{147}\) Z. Turb. 1911, S. 287.
\(^{148}\) Hütte, 21. Aufl. 1911, II. S. 222.
\(**\) Z. V. d. I. 1907, S. 346.
\(^{149}\) Losse, Neuere Kraftmaschinen. Berlin, 1905, S. 78.
\(^{150}\) Moyer, Steam. turb., p. 151.
\(^{151}\) Techn. u. Wirtsch. 1912. S. 531.
\(^{152}\) Z. V. d. I. 1912, S. 997.
the exhaust velocity in it considerably exceeded 405 m/sec.; for \(p_0=0.04\div0.10\) the decrease in \(D\) was about 1.6%. Stodola \(^{148)}\) gives, for superheated steam at \(t=300^\circ\), for \(p_0=0.10\) a decrease in \(D\) of 1.5%, for \(p_0=0.04\) already 2.4%, and, finally, for \(p_0=0.02\) even 5.2%.
In conclusion it should also be mentioned that some works guarantee a certain steam consumption not at a specified pressure \(p_0\) in the condenser, but at a specified temperature \(t_v^\circ\) of the cooling water as it enters the surface condenser, assuming, of course, a sufficient supply of it. Let us indicate two examples: in the delivery of an Ehrlikon turbogenerator of 3200 kW, the works guaranteed the steam consumption \(D_k\) per 1 kWh, including also the consumption for cooling, according to Table 14 \(^{153)}\).
Table 14.
| 30 | 35 | 40 | 45 | ||
|---|---|---|---|---|---|
| water temperature \(t_v\) | °C | 30 | 35 | 40 | 45 |
| steam consumption \(D_k\) | kg/kWh | 9.6 | 10.45 | 11.3 | 12.0 |
| maximum load developed \(N_k\) | kW | 3000 | 2750 | 2550 | 2400 |
| full steam consumption | kg/h | 28800 | 28730 | 28820 | 28800 |
Starting from the mean \(t_v=35^\circ\), it may be said that a change of \(t_v\) by \(5^\circ\), corresponding to a change of \(p_0\) by \(0.01\div0.02\) atm., gives for the given turbine a change in \(D\) of 6.7–8.1%.
It is further interesting to draw attention to the last (calculated by us) line of Table 14, which confirms the general law, established by Stodola \(^{154)}\), that the steam consumption, with its initial state constant, with a constant number of turbine revolutions, and at the greatest load, does not depend on fluctuations of the vacuum. This same law is also confirmed by Lezel’s tests \(^{155)}\). Making use of this law, we obtain the following simple method for determining the consumption \(D\) for variable \(p_0\), or, what is the same, \(t_v\): measure as accurately as possible the full steam consumption \(G\) kg/h at the greatest load and at some \(p_0\), or, better for checking, at 2 different \(p_0\)’s and then take the mean value \(G\); measure the magnitudes of the greatest load \(N_1, N_2,\ldots\) at the same initial state of the steam and number of revolutions \(n\), but at other \(p_{01}, p_{02},\ldots\); the required consumption \(D\) per 1 kW or 1 h.p. is obtained by dividing the constant quantity \(G\) by the corresponding greatest power.
A second example of allowing for the influence of the temperature of the cooling water is given by a report of Gerken \(^{151)}\), chief engineer of the Augsburg-Nuremberg works, which build Zoelly turbines. According to the data of this works, which regards \(t_v=15^\circ\text{C}\) as the normal value, a lowering of \(t_v\) by \(5^\circ\) gives
\(^{153)}\) Z. Turb. 1909, p. 175.
\(^{154)}\) Stodola, Dampfturb., p. 215.
decrease of \(D\) by approximately \(1.3\%\), and an increase by \(5^\circ\)—an increase of \(D\) by \(1.7 \div 1.9\%\).
Incidentally, we shall present here a very clear and convenient graphical method, used by Gerken, for taking into account the influence of all the quantities listed above on the steam consumption \(D\): choose the normal initial and final state of the steam; for Gerken, \(p=12\) atm. abs., \(t=325^\circ\) and \(t_{\mathrm{w}}=15^\circ\); and plot curves of the change of \(D\) in percent, laying off \(\Delta D\%\) on the ordinate axis, and the corresponding values of \(p\), \(t\), and \(t_{\mathrm{w}}\) on the abscissa axes, Fig. 354; all three curves pass through one common point, when \(\Delta D=0\): above the abscissa axis,
passing through this point, the values \(\Delta D\) are positive, i.e., the consumption increases; below it they are negative, the consumption decreases; curve \(a,a\) gives the values of \(\Delta D\) when the steam pressure \(p\) changes from 9 to 15 atm. abs.; curve \(b,b\)—when the steam temperature \(t\) changes from \(265^\circ\) to \(375^\circ\) C.; curve \(c,c\)—when the temperature \(t_{\mathrm{w}}\) of the cooling water changes from 3 to \(29^\circ\) C. With the aid of the diagram in Fig. 354, the corrections \(\Delta D\) for the deviation of \(p\), \(t\), and \(t_{\mathrm{w}}\) during the test of the given turbine from the normal values are found as follows; for example, for \(p\): through the point on the \(p\) scale corresponding to the pressure \(p\) that occurred during the test, draw a straight line parallel to the ordinate axis until it intersects curve \(a,a\), and from this point of intersection draw a straight line parallel to the abscissa axis until it intersects the ordinate axis, on which it directly gives the value of the required correction \(\Delta D\); in the same way the corrections are found for the influence of \(t\) and \(t_{\mathrm{w}}\). Of course, for each turbine, or at least for each type of turbine, the curves \(p\), \(t\), and \(t_{\mathrm{w}}\), or \(p\), \(t\), and \(p_0\), must be constructed on the basis of the corresponding experimental material.
We shall then give Table 15, in which are collected both the above-indicated values of the change \(\Delta D\) in percent, and others, taken from those
§ 48. Reduction of the magnitude of steam consumption.
the same sources, and which, on the one hand, gives the limits within which they fluctuate, and, on the other, clearly shows the necessity of experimentally finding the corresponding corrections for each turbine, depending on its capacity and actual working conditions.
Table 15.
| Change | Laval | Brown-Boveri-Parsons | Westingh. Parsons | Curtis | Brown-Curtis | Rateau-Oerlikon | Zoelly | All systems, Stodola | All systems, Hütte |
|---|---|---|---|---|---|---|---|---|---|
| \(p\) by 1 atm. | — | \(1.0 \div 2.0\) | 1.4 | \(1.4 \div 3.0\) | — | — | 2.1 | \(1.0 \div 1.7\) | — |
| \(t\) by \(10^\circ\) C | \(1.1 \div 1.4\) | \(1.3 \div 2.0\) | \(1.2 \div 1.3\) | \(1.4 \div 1.8\) | \(1.0 \div 1.8\) | \(1.0 \div 2.4\) | 1.5 | 1.3 | \(1.4 \div 2.0\) |
| \(x\) by \(0.01x\) | — | — | 2.0 | — | 0.6 | — | — | 1.0 | — |
| \(p_0\) by 0.01 atm. | \(0.8 \div 1.4\) | \(+1.5 \div 2.0;\ 3.0(0.65)\) | \(1.0 \div 1.7\) | \(+1.0 \div 2.0\) | — | \(1.6 \div 2.0\) | \(+1.0 \div 2.0\) | \(1.5;\ 2.4;\ 5.2\) | \(1.0 \div 3.9\) |
| \(t_{\mathrm{в}}\) by \(5^\circ\) C | — | — | — | — | — | \(3.4 \div 8.1\) | \(1.3 \div 1.9\) | — | — |
The experimental way to find the correction \(\Delta D\) is as follows: in order to determine the influence of one of the three quantities, \(p\), \(t\), respectively \(x\), and \(p_0\), respectively \(t_{\mathrm{в}}\), 2–3 experiments are made, varying within as wide limits as possible the quantity whose influence is being investigated, and keeping, as far as possible, the other two quantities and the load—or, still better, the total steam consumption \(G\) kg/hr—the same. From the values of consumption \(D\), kg/hp·hr, found in this way, a curve of \(D\) is constructed as a function of the quantity that was varied. This curve, in the extreme case with the aid of the corresponding extrapolation, graphical or analytical, gives the required correction \(\Delta D\). Then, in the same way, the magnitudes of the corrections from the other two quantities are found.
Normal conditions, i.e. the \(p\), \(t\), or \(x\) and \(p_0\) to which the quantities \(D\) obtained under other conditions are to be reduced, are entirely conventional and arbitrary. Thus, formerly it was considered normal to take for \(p\) 10 atm. gauge, for \(t\) only \(250^\circ\), and for \(p_0\) 90% (0.10 atm.). With the advances of technology the limits have been extended: not so long ago it was considered normal for \(p\) to be 12 atm. abs., for \(t\) already \(300^\circ\), and for \(p_0\) 0.052 atm. abs., or 95% vacuum.
In the very latest period the limits have been extended still further; thus, the Augsburg-Nuremberg works considers normal: \(p = 12\) atm. gauge, \(t = 325^\circ\), and instead of \(p_0\) gives \(t_{\mathrm{в}} = 15^\circ\), which, assuming a temperature difference of \(10^\circ\) between the water and the steam in a counterflow condenser, gives \(p_0 = 0.032\) atm. abs., or 97% vacuum.
It is very possible that in time there will be a tendency toward a further increase of \(p\) and \(t\) and a decrease of \(p_0\). The moisture of the steam \(x\) is already regarded as wholly inadmissible, and it is only very rarely necessary to deal with it.
Thus, it is impossible, and not so important, to specify definite normal values of \(p\), \(t\), and \(p_0\). One may use those most widespread at the given time and, when giving the reduced consumption
\[ D' = D + \sum \Delta D, \]
state which coefficients have been taken as the basis for the reduction to the normal state.
Finally, it may also be pointed out that, if one wishes to compare only two turbines with one another, which have operated under different conditions, or the consumption of one and the same turbine but at different loads, then, in view of the insufficient definiteness of the magnitudes of the reduction coefficients and the incomplete following of the magnitudes \(D\) to the law of an inclined straight line, it is better to reduce the comparative consumptions \(D\) not to any normal values \(p\), \(t\), and \(p_0\), but to the arithmetic means of those which occurred during the corresponding tests; then the absolute magnitudes of the corrections \(\Delta D\) are comparatively small, and the relative inaccuracy of their determination is considerably reduced.
Influence of load. The steam consumption \(D\) is also appreciably affected by the magnitude of the load. In view of the fact that a turbine often has to operate not at full load, it is very important that, as the load is decreased, the magnitude \(D\) should not increase too rapidly.
Thus the determination of \(D\) at various loads—most often, besides \(1/1\), also at \(3/4\), \(1/2\), and \(1/4\) of full load—is included in every test, both acceptance and works tests. For clarity, it is useful to represent the results graphically, taking the magnitudes of the load as the abscissa axis, and plotting the corresponding magnitude \(D\) along the ordinate axis.
Chart 355.
In Chart 355 an example is given of these curves \(D\) for different loads and for 3 different initial states of the steam: \(D_1\) at \(p = 10\) atm., \(t = 230^\circ\text{C}\); \(D_2\) at \(p = 10\) atm., \(t = 300^\circ\text{C}\); \(D_3\) at \(p = 14\) atm., \(t = 300^\circ\text{C}\). These curves are taken from Zinger’s report on the test of a turbogenerator.
§ 48. Influence of load on steam consumption.
Brown-Boveri-Parsons of 3200 kW, installed in Frankfurt am Main in 1905.¹⁵⁵) In addition to the curves \(D\), in Fig. 355 the corresponding curves \(G_1\), \(G_2\), and \(G_3\) of the total steam consumption in kg/hour are shown for the same 3 combinations of \(p\) and \(t\). As can be seen, the curves are inclined straight lines, whose ordinate equation is
\[ y = ax + b, \tag{107} \]
where \(b\) is the steam consumption at idle running, without load, but with expenditure of energy for excitation; \(x\) is the magnitude of the load in fractions of full load, and \(a\) is an empirical constant.
In Fig. 356 are presented the results of testing a Zoelly turbine of 2300 kW,¹⁵⁶) operating at \(p = 12\) atm. abs., \(t = 320^\circ\text{C}\), and dilution of 93%. Curve \(D_1\) represents the steam consumption in kg/kW h, guaranteed by the works; \(D_k\) is that actually found; \(D_e\) is the consumption in kg/h.p. h. In addition to these curves, in Fig. 356 there is also drawn the curve \(p\)—the pressure of live steam before the first guide apparatus when the load changes.
Fig. 356.
The simple dependence, indicated by equation (107), between the load and the hourly steam consumption \(G\) makes it possible, from the three consumption values found during the test, to obtain with sufficient accuracy the steam consumption for any load from 0 to \(1/1\), by constructing the indicated straight line, and it also readily reveals errors in the test if a new ordinate in a subsequent test falls noticeably far from the straight line drawn.
Of course, if the load is increased above \(1/1\), i.e., if the turbine is overloaded, the steam consumption will begin to increase more rapidly, in view of
¹⁵⁵) Brown, Boveri & Cie, Dampfturb., S. 61; Turb., 2, 1905/6, S. 158; Lehmann-Richter, Prüfungen in elektr. Zentralen. Braunschweig, 1906. II, S. 210.
¹⁵⁶) Z. V. d. I. 1910, S. 330.
noncorrespondence of the flow sections in the turbine to the increased quantity of steam; the line \(G\) will pass into a curve bending upward, while the curve \(D\), descending as the load increases to \(1/1\), will then begin to rise, forming a minimum at the load \(1/1\).
However, this kind of overload in European practice occurs only in marine turbines; turbogenerators never operate, and cannot operate, with an overload above \(10\text{--}20\%\). The situation is different in America; there every turbogenerator is built so that it can operate for a long time with an overload up to \(50\%\), sometimes even up to \(100\%\). The diagrams in Fig. 357 may serve as a typical example; these are the results of testing a 1000-kW Westinghouse-Parsons turbine under 4 different conditions \(^{57}\): curves \(G_1\) and \(D_1\) were obtained at \(p=10.56\ \mathrm{kg}/\mathrm{cm}^2\) abs., \(t=\theta=181.5^\circ\mathrm{C}\), saturated steam, \(p_0=1\) atm.;
Fig. 357.
curves \(G_2\) and \(D_2\) at the same \(p\) and \(p_0\), but with superheated steam, \(t=237.1^\circ\); curves \(G_3\) and \(D_3\) at \(p=10.56\), \(t=\theta=181.5^\circ\), but with a condenser, \(p_0=0.065\ \mathrm{kg}/\mathrm{cm}^2\) abs., corresponding to \(93.5\%\) vacuum; finally, curves \(G_4\) and \(D_4\) at the latter \(p\) and \(p_0\), but with superheating, \(t=237.1^\circ\).
On the curves \(G\) breaks are visible at the beginning of overload, while the curves \(D_e\), incidentally, indicating the steam consumption in \(\mathrm{kg}/\mathrm{h.p.\,h}\), and not in \(\mathrm{kg}/\mathrm{kW\,h}\), show a clearly expressed minimum. Finally, when operating with a condenser, the curve \(D\) at a load of about \(1\frac{1}{3}\) passes from convex toward the axis of abscissas to concave; this is explained by the beneficial influence of the automatic overload valves, which begin to admit steam into the intermediate stage when the overload is increased excessively. Although the turbogenerator is rated at 1000 kW, for some reason in the cited report the full load \(1/1\) is given as 1050 kW. Fig. 357 shows that the turbogenerator is capable of operating with
\(^{57}\) Moyer, Steam turb., p. 171.
with a load of 2150 kW, i.e., with an overload of \((2150-1050):1050 = 105\%\) (!). Such machines are not to be found in Europe.
Allowance for the effect of load. If in some test the steam consumption \(G\) is found for some two or three loads, the magnitudes of which, however, do not correspond to those for which the guaranteed values \(D\) are specified, then \(D\) at other loads can be found very simply in the following way: construct, as indicated above, the curve \(G\), as in Figs. 355–357; for several points find the quantities \(D = y/x\), where \(y\) are the ordinates expressing the consumption \(G\), and \(x\) the abscissae expressing the magnitude of the load in h.p. or kW; connecting the points thus found by a smooth curve, we obtain the curve \(D\), the ordinates of which at the point expressing the required load give the corresponding steam consumption in kg/hr per unit of power.
The steam consumption at no load may be found by extending the straight line \(G\) to its intersection with the axis of ordinates. The length of the ordinate at a load equal to 0 is the desired consumption.
Magnitude of the consumption \(D\). We shall not weary the reader with an enumeration of the steam consumption attained by turbines of various systems, of different power, and under different operating conditions. Nor do we venture to compile a corresponding table, especially in view of the difficulty of reducing all consumptions to identical operating conditions; such a table at the present time would prove too cumbersome, not very clear, and not very interesting, since it is now possible to state with sufficient accuracy the following proposition: the steam consumption of modern turbines, at equal power and equal \(p\), \(t\), and \(p_o\), is approximately the same for all systems, having in view, of course, products of first-class factories. Therefore we shall confine ourselves only to the following historical note: small Laval turbines in their time consumed up to 30 kg/kW hr; at present these turbines, at a power of about 200 kW, consume about 10 kg/kW hr of saturated steam and only 8.7 of superheated steam, while a multistage Laval turbine of 1500 kW gives a consumption of only 7.0 kg/kW hr. Parsons turbogenerators, which gave a consumption of 9.0, now give about 7.0, and with superheat only 5.9 and even 5.7 kg/kW hr. Curtis turbines, which consumed up to 10–11 kg/kW hr, at the present time, admittedly at powers of 7000–9000 kW, consume about 5.9 kg of superheated steam. The Rateau turbine is somewhat behind; it has reduced its consumption from 9.6 to 7.5 kg/kW hr. Finally, Zoelly turbines, which only three years ago gave a consumption of about 8.2 and in the best case 7.4 kg/kW hr, have now attained a consumption of 5.9 kg/kW hr, and this at a power of only about 1500–2000 kW. A consumption of 5.9 kg/kW hr corresponds to a consumption of 3.99 kg/d.h.p. hr on the turbine shaft, or only 3.7–3.8 kg/ind. h.p. for a piston engine. The same figure, 5.9 kg/kW hr, has now been reached by a Melms and Pfenninger turbine at a power of 3000
hp, which in the first designs gave a consumption of up to 7.8 kg/kWh, though at a power of about 900 hp.
49. Derivation of general conclusions.—When a detailed test of a turbine is carried out, then, in order to characterize the merit of the given turbine, its efficiency \(\eta\) is calculated.
Calculation of efficiency. Of the numerous efficiencies \(\eta\) with which one has to deal in turbine calculations, in testing turbines two are of chief interest: the so-called thermodynamic efficiency\({}^{158}\), referred to the actual work,
\[ \eta_e=N_e/N_o=D_o/D_e, \tag{108} \]
where \(N_e\) is the work, in hp, of the given turbine, and \(N_o\) that of an ideal turbine without losses, operating between the same \(p, t\) and \(p_o\), and consuming the same quantity of steam \(G\) kg/hr; while \(D_e\) and \(D_o\) are respectively the steam consumption in kg/hp hr; the second efficiency is the total efficiency\({}^{158}\)
\[ \eta_o=AL_e/Q, \tag{109} \]
where \(AL_e\) is the work, in heat units, of 1 kg of steam performed in the turbine, and \(Q\) is the expenditure of heat for producing steam, the state of which is determined by \(p\) and \(t\).
For equation (108) the quantity \(D_e\) is found in the test, as indicated above, and the quantity \(D_o\) from the expression
\[ D_o=632.3:(i-i_k'), \tag{110} \]
where \(i\) is the total heat content of the steam, determined by the pressure \(p\) and temperature \(t\) before the turbine, and \(i_k'\) is the heat content of this same steam at the exhaust pressure \(p_o\) after complete adiabatic expansion without any resistances; the quantities \(i\) and \(i_k'\), or directly their difference, are most often found from the well-known Mollier \(J—S\) diagram.
For equation (109) the quantity \(AL_e\) can also be found from \(D_e\), namely,
\[ AL_e=632.3/D_e, \tag{111} \]
and the corresponding heat consumption \(Q\) is equal to the total heat content of 1 kg of steam at \(p\) and \(t\), i.e. \(i\), minus the heat content of 1 kg of feed water, practically equal to its temperature \(t_v\), i.e.
\[ Q=i-t_v. \tag{112} \]
It must be noted that at the present time, at least in Europe, the total efficiency \(\eta_o\) is almost never calculated, and the economy of a turbine is judged by the steam consumption \(D_e\) or \(D_k\). Thus, if a test report speaks of efficiency without saying which, then the thermodynamic efficiency is meant, which in modern turbines ranges from \(\eta_e=0.13\) to 0.18 and even to 0.20.
Along with the above method of calculating thermodynamic efficiency, indicated by Stodola\({}^{158}\), one may also encounter another method, in which the quantity \(D_e\) is likewise found from the \(J—S\) diagram analogously to \(D_o\)\({}^{159}\), namely,
\[ D_e'=632.3:(i-i_k), \tag{113} \]
\({}^{158}\) Stodola, Dampfturb., S. 113.
\({}^{159}\) Z. V. d. I. 1908, S. 1346.
§ 49. Obtaining general conclusions.
where \(i_k\) is the heat content, determined from the actual state of the steam at exhaust, i.e., from \(p_o, t_o\) or \(x_o\). Obviously, the difference between this method and the first consists in the fact that it does not include purely mechanical losses, friction in the bearings, expenditure of energy on regulation and on the oil pump in the corresponding cases, as well as losses from leakage of steam from labyrinth seals and unloading pistons. However, the value \(D_e'\) according to equation (113) is only slightly less than the value \(D_e\) found by direct test, and it is only necessary, if \(\eta_e\) has been found from \(D_e'\) by equation (113), to state this clearly in the test report.
However, equation (113) must also be used for another purpose. Namely, it makes it possible to determine the quantity characterizing the final state of the steam at a known exhaust pressure \(p_o\) kg/cm\(^2\) abs., i.e., the temperature \(t_o\), if the steam is still superheated, or the steam content \(x_o\), if it is wet.
In fact, if \(D_e\) has been measured, and \(i\) has been determined from the pressure \(p\) and temperature \(t\), then from equation (113) we find
\[ i_k = i - 632{,}3/D_e; \tag{114} \]
having thus calculated the quantity \(i_k\), we find the corresponding \(t_o\) or \(x_o\) from the \(J—S\) diagram at the intersection of the line \(p_o\) with a line parallel to the axis of abscissas and separated from it by the amount \(i_k\).
In conclusion, it must also be mentioned that in a detailed test, besides the efficiency \(\eta_e\) of the whole turbine, the efficiencies of the individual stages are calculated from the intermediate pressures \(p\) and temperatures \(t\). In these cases one is necessarily obliged to use the value \(D_e'\), or it is simpler to calculate \(\eta_e\) from the set of equations (108), (110), and (113), according to the expression
\[ \eta_e = \frac{i-i_2}{i-i_2'}. \tag{115} \]
However, it must be noted that equation (115) gives correct results only under the assumption that heat is neither removed to the outside nor received. If heat is removed, then the value of \(\eta_e\) proves to be overestimated; if it is supplied, then it is underestimated. The first case often occurs in the last stage of multistage turbines, and the latter in the first stage, if, as is often done, the turbine casing at this place is covered with an insulating layer. Of course, having found in the manner indicated above the heat losses by radiation from the individual stages of the turbine, one can calculate the corresponding corrections to the temperatures \(t\) and thereby find more correct values of \(i\). However, the difference is usually small, and the correction should be introduced only in the most careful scientific investigations.
A second source of error in calculating \(\eta_e\) for individual stages may lie in insufficient observance of the condition of a fully established state: if the steam temperature fluctuates, for example,
Chapter IX. Production of Tests. § 49.
increases, then part of the heat goes to heating the metallic masses of the turbine, and the value \(\eta_e\) proves to be overestimated; in the period of the reverse fluctuation, a lowering of the steam temperature, \(\eta_e\) is obtained underestimated. The error resulting from this may, at small loads, i.e., at a small total steam consumption, attain a very considerable magnitude. Since it is very difficult, especially in factory tests, to maintain the steam temperature strictly constant, in order to reduce the indicated error it is useful to employ the following method, indicated by Marguerre8: from the temperature readings of the steam before the turbine, between the individual stages, and at exhaust, plot the course of the temperature as a function of time at the indicated places; then take on the curve of the temperature before admission to the turbine 2 points where the temperature is the same, but at one point it is falling, and at the other it is rising. As the temperatures at the remaining places of the turbine, for determining the points on the \(J—S\) diagram, take the arithmetic means of the corresponding temperatures at these same 2 instants. Having thus computed the values \(\eta_e\) for several pairs of temperatures for the whole turbine, find the mean value \(\eta_e\) for the entire experiment. If \(\eta_e\) is computed for an individual stage, then the pairs of equal temperatures must be taken on the temperature curve before the corresponding stage.
In Fig. 358 a sample of the corresponding curves is given for one of Marguerre’s tests; the curves refer to 5 points in the turbine—\(I\) before the nozzles of the active wheel, \(II\) behind it, \(III\) before the first reaction stage, \(VI\) in its middle, and \(V\) before the last stage; the temperature curve at exhaust is not given, so that from Fig. 358 it is impossible to compute
Fig. 358.
by the active-wheel nozzles, \(II\) behind it, \(III\) before the first reaction stage, \(VI\) in its middle, and \(V\) before the last stage; the temperature curve at exhaust is not given, so that from Fig. 358 it is impossible to compute.
§ 49. Graphical Representation of Results.
\(\eta_e\) neither for the entire turbine nor for the last stage, except perhaps only if the temperatures are regarded as constant, \(t_0 = \vartheta_0\), and they are found from the corresponding \(p_0\) and in connection with Eq. (114). In Fig. 358 the use of pairs of temperatures \(t = 290^\circ\) for calculating \(\eta_e\) for the first stage is shown.
Graphical representation of results. In addition to compiling the test results into a table, a specimen of which is given below, pp. 298 and 299, it is very useful to represent the results graphically by diagrams.
We have already become acquainted above with one type of diagram—plane curves of the variation of one quantity as a function of another, for example, the steam consumption \(D\) as a function of load, or the moment of resistance as a function of the number of revolutions or of the steam density. It is enough to recall Figs. 337, 339, 340, 355–358. In some of these it is convenient to combine two and even more curves with different ordinates, for example Figs. 339, 355–357; another example of combining several curves we saw in Fig. 354.
A second type of diagram may be considered to be the representation of the actual working process of the steam according to the test in the heat diagram in coordinates \(I—S\); such a diagram is most simply obtained by plotting the corresponding points on tracing paper, under which a printed Mollier diagram has been placed. The plotting of the individual points is done, in general, in the same way as in drawing the theoretical working process, of which enough has been said in various handbooks, for example, Stodola\({}^{160}\), Eberman\({}^{161}\), or in the corresponding articles\({}^{162}\).
Occasionally one resorts to representing the working process in coordinates \(T—S\), for example Fig. 338, but in them it is much less clear, and the use of this entropy diagram is considerably less convenient.
Finally, a third type of diagram may be considered the so-called Sankey diagram. This very widespread method in America, a means of giving visual clarity to some complex phenomenon, may be referred to diagrams with one dimension, or linear diagrams; to the second dimension there is sometimes assigned a certain significance, but one that is purely conventional, not to scale.
With the aid of the Sankey diagram it is very convenient to represent the working process of a turbine from the point of view of the distribution of heat or of steam consumption.
In Fig. 359, p. 296, a specimen of a Sankey diagram is presented, showing the heat balance of a turbo-generator V. K. E. of 1000 kW in connection with the operation of a steam boiler.
Another specimen of a Sankey diagram is given in Fig. 360. It presents the distribution in % of the quantity of steam during operation at the specified—
\({}^{160}\) Stodola, Dampfturb., S. 146.
\({}^{161}\) Eberman, Steam Turbines. SPb. 1907, p. 57.
\({}^{162}\) See, for example, Bulletin of the Polytechnic Society, Moscow, 1907, p. 233 ff., or Z. V. d. I. 1911, S. 1847.
Chapter IX. Conducting Tests. § 49.
amounting to many times more than that of the Parsons turbine of 300 kW9: \(a\)—front labyrinth seal, \(b\)—rear seal, \(I, II\), and \(III\)—corresponding stages of the turbine, \(1, 2\), and \(3\)—corresponding unloading pistons.
Fig. 159.
Visible annotations in the diagram: “Loss in the steam pipe”; “30,000 units = 4.37%”; “Loss in the steam pipe”; “95,300 units = 1.39%”; “Loss in the guide vanes”; “5,252,940 units”; “Loss in wheel friction”; “190,000 units”; “6,882,983 units = 100%”; “Heat content of steam”; “36,000 units = 0.52%”; “Loss by cooling—non-condensate”; “4,293,360 units”; “Passed into electrical energy”; “858,980 units = 12.47%”; “Exhaust steam: water, surface condensate”; “4,082,360 units = 59.31%.”
Fig. 360.
Visible annotations in the diagram: \(100\%\); \(a\); \(3\); \(2\); \(1\); \(1.6\); \(1.8\); \(1.36\); \(76^\circ\); \(I\); \(II\); \(III\); \(b\); \(100\%\).
With the aid of the Sankey diagram it is convenient to represent in % the distri-
§ 49. Graphical Representation of Results.
the division of the heat converted into work in the individual stages of the turbine, and of that going to the various losses.
Summary of results. In conclusion we give a specimen summary of the results of a series of turbine tests, taken from the model report of the Stodola Department on the testing of a Zoelly turbine of 2000 hp. \(^{164}\), Table 16, pp. 298 and 299. At the same time Table 16 may serve as an example from the practice of a report on tests and as the last journal from the series given above in Tables 6—13.
Additions.
While the present work was being printed, the author received several new data from factories and firms, and also noticed several omissions in using the literature sources; finally, during the printing of the work, articles appeared touching on the same questions. In concern for the completeness of the information communicated, the author decided to take into account all the new material as well. Since the corresponding pages had already been printed, it was necessary to resort to additional insertions, before which are indicated the §, the page, and, in italics, the line after which the place of insertion is found.
3, p. 17, 1 from the bottom. Tachometer based on the friction of air. The Perboom and Schormann works have recently begun, for machines with a large number of revolutions, in particular for steam turbines, to manufacture a special instrument consisting of two light wheels of the type of the vane wheels of high-speed water meters; one of the wheels is formed by radial ribs in an aluminum drum and is seated on an axle driven into rapid rotation by the machine; the other, also an aluminum wheel, is located inside this drum; to the projecting axle of the second wheel is attached a light disk with a dial on top. Between the rims of the wheels there is a very small clearance, in consequence of which the air, set in rotation together with the drum, tends by its friction to carry along the free wheel and in doing so tensions a spiral spring which prevents it from rotating together with the drum. The scale of this instrument is graduated experimentally; its indications do not depend on temperature and do not change with time; the wear of the instrument, in view of the very small number of moving parts, is very slight. The sensitivity and accuracy of the instruments are very great—down to \(1/10\%\); divisions of equal magnitude over the whole scale.
7, p. 33, 14 from the top. An interesting tachogram, Fig. 363 \(^{165}\), taken from a Mells and Pfenniger turbine of 1700 hp and showing the action of the safety regulator, which automatically closes the main steam valve when the number of rev./min. \(n\) exceeds a defin—
\(^{164}\) Z. V. d. I. 1911, S. 1799.
\(^{165}\) Taken from the brochure Dampfturb. Mehns & Pfenniger, G. m. b. H., München-Hirschau. S. 21.
Table 16.
Summary table of test results for Zimmerman tubes, of normal strength 2000 kg, installed at the electric station in the city of Basel.
| Row | Test No. | 1 cold with overheating and excitation 60 min. |
2 1/4 (0.30) 75 |
3 1/2 (0.52) 60 |
4 3/4 (0.78) 45 |
5 1/1 (1.03) 35 |
6 5/4 (1.26) 90 |
7 cold without overheating 45 |
|---|---|---|---|---|---|---|---|---|
| 1 | I, steam turbine: pressure in the boiler |
13.45 | 12.75 | 12.60 | 12.19? | 12.47 | 12.06 | 4.30 |
| 2 | steam temperature (average from 3 boilers) | 316.7 | 280.3 | 270.8 | 282.2 | 292.4 | 288.0 | 197.5 |
| 3 | pressure before regulating valves | 13.31 | 12.59 | 12.56 | 12.35 | 12.52 | 11.58 | 4.5 |
| 4 | temperature before them | 286.4 | 289.4 | 238.9 | 288.3 | 289.6 | 287.2 | 170.3 |
| 5 | pressure before nozzles | — | 4.14 | 6.40 | 9.05 | 11.12 | 10.15 | 0.500 |
| 6 | temperature before nozzles | 236.8 | 274.1 | 277.2 | 275.5 | 284.8 | 282.1 | 149.7 |
| 7 | pressure before nozzles ahead of the 1st overpressure wheel | — | — | — | 1.42 | 1.87 | 8.14 | — |
| 8 | temperature | — | — | — | 229.7 | 262.8 | 278.3 | — |
| 9 | pressure before nozzles ahead of the 2nd overpressure wheel | — | — | — | 1.43 | 1.82 | 2.40 | — |
| 10 | temperature | — | — | — | 239.2 | 261.8 | 270.2 | — |
| 11 | pressure before the 1st drum | 0.199 | 0.883 | 1.043 | 1.445 | 1.842 | 2.356 | 0.116 |
| 12 | temperature | 167.2 | 188.5 | 165.7 | 180.8 | 191.3 | 214.0 | 100.2 |
| 13 | pressure before the 2nd drum | 0.101 | 0.320 | 0.480 | 0.680 | 0.857 | 1.046 | 0.067 |
| 14 | temperature | 108.9 | 124.7 | 125.5 | 120.1 | 129.2 | 139.6 | 82.9 |
| 15 | pressure before the 3rd drum | 0.057 | 0.133 | 0.200 | 0.300 | 0.350 | 0.435 | 0.035 |
| 16 | temperature | 66.3 | 64.8 | 66.6 | 66.5 | 72.3 | 78.5 | 84.3 |
| 17 | pressure in the exhaust pipe, $p_0$ | 0.041 | 0.042 | 0.043 | 0.050 | 0.052 | 0.060 | 0.040 |
| 18 | temperature | 27.3 | 29.2 | 29.2 | 32.1 | 32.0 | 34.5 | 39.5 |
| 19 | average number of revolutions, $n$ | 1502 | 1502 | 1502 | 1502 | 1501.3 | 1502.7 | 1502.2 |
| 20 | value $t_0 - t_0$ at the superheated-steam line | 0 | 0 | 0 | 0 | 0 | 0 | 60.7 |
| 21 | II, refrigerator: barometer height |
736 | 736 | 736 | 736 | 736 | 736 | 736 |
| 22 | pressure in the discharge-air pipe | 0.044 | 0.043 | 0.042 | 0.050 | 0.046 | 0.045 | 0.041 |
§ 49. Summary of Results.
| No. | Indicator | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| 23 | temperature in the tube for exhaust air, °C | 18,2 | 19,0 | 19,8 | 20,4 | 21,0 | 24,3 | 21,5 |
| 24 | pressure in the air duct for exhaust air, kg/cm² abs. | 0,046 | 0,043 | 0,043 | 0,051 | 0,047 | 0,049 | 0,041 |
| 25 | temperature, °C | 19,0 | 19,9 | 20,8 | 21,6 | 22,4 | 24,5 | 21,8 |
| 26 | pressure from the reference level, kg/cm² abs. | 0,044 | 0,044(?) | 0,044(?) | 0,049 | 0,047 | 0,049 | 0,041 |
| 27 | condenser temperature, °C | 17,2 | 21,4 | 24,6 | 26,4 | 30,0 | 30,7 | 17,9 |
| 28 | cooling water before the refrigerator, °C | 15,9 | 16,0 | 16,0 | 16,3 | 16,5 | 16,5 | 16,4 |
| 29 | same, between the 3rd and 4th passes, °C | 16,9 | 19,1 | 21,3 | 23,3 | 22,9 | 25,8 | 18,4 |
| 30 | same, at the outlet from the refrigerator, °C | 17,1 | 20,4 | 23,1 | 24,4 | 26,4 | 28,7 | 19,6 |
| 31 | head of the cooling water in the refrigerator, kg/cm² | 0,149 | 0,146 | 0,139 | 0,103 | 0,204 | 0,207 | 0,114 |
| 32 | III. Lubrication: oil pressure in the discharge line, kg/cm² | 1,27 | 1,41 | 1,44 | 1,46 | 1,44 | 1,46 | 1,31 |
| 33 | same, under the discharge-plate, kg/cm² | 1,51 | 4,64 | 6,81 | 9,32 | 10,72 | 12,95 | 1,50 |
| 34 | temperature of the oil in the tube of the bearing at the worm, °C | 44,1 | 45,2 | 45,8 | 46,6 | 48,5 | 51,2 | 42,7 |
| 35 | same, at the refrigerator, °C | 43,4 | 45,9 | 46,0 | 46,5 | 47,4 | 48,4 | 42,4 |
| 36 | same, in the sump of the drive dynamo to the exciter, °C | 47,0 | 47,9 | 47,2 | 48,1 | 49,3 | 50,2 | — |
| 37 | same, in the exciter, °C | 57,6 | 57,9 | 58,2 | 58,3 | 59,1 | 59,2 | — |
| 38 | same, before the refrigerator, °C | 38,5 | 40,2 | 41,1 | 42,2 | 44,0 | 45,5 | 34,6 |
| 39 | same, after the refrigerator, °C | 16,7 | 34,3 | 36,3 | 37,0 | 38,9 | 40,2 | 30,9 |
| 40 | IV. Power, work, recoil: oil consumption, kg/h | 84,8 | 98,5 | 102,6 | 109,8 | — | — | 75,3 |
| 41 | oil, expelled by pressure, kg/h | 76,4 | 75,7 | 101,2 | 75,6 | 78,7 | 77,3 | 59,2 |
| 42 | oil, passing into the pipe, kg/h | — | — | 106,3 | 155,7 | — | — | — |
| 43 | power, consumed by the turbine, kW (approximately) | 20 | 20 | 20 | 20 | 20 | 20 | 20 |
| 44 | mean vacuum in the condenser according to the mercury manometer, in. Hg | 0,2030 | 0,6975 | 0,7331 | 0,9344 | 0,9345 | 0,6600 | 0,3732 |
| 45 | number of revolutions (mean for $l = 20{,}06$ mm) | 1 | 2 | 3 | 4 | 5 | 7 | 1 (7—83) |
| 46 | isothermal coefficient according to the curve | 0,9666 | 0,9668 | 0,9671 | 0,9688 | 0,9682 | 0,9064 | 0,949 |
| 47 | measured quantity of condensate, kg/h | 1396 | 5177 | 7964 | 11340 | 14178 | 14018 | 7672 |
| 48 | water through the compensating vessel, kg/h | 1,4 | 1,5 | 1,7 | 1,4 | 1,6 | 1,6 | 1,5 |
| 49 | total consumption of steam $G$, kg/h | 1417 | 5198 | 7986 | 11362 | 14199 | 17640 | 7887 |
| 50 | expansion work, kW | 0 | 694 | 1049 | 1560 | 2053 | 2521 | — |
| 51 | steam consumption for the refrigerator and ventilator, kg/h | 33,5 | 33,3 | 33,7 | 34,3 | 34,8 | 35,1 | — |
| 52 | useful work of the generator, kW | 0 | 500,2 | 1015,3 | 1525,7 | 2023,2 | 2488,9 | — |
| 53 | steam consumption $D_k$ gross, kg/kWh | — | 8,75 | 7,61 | 7,23 | 6,90 | 7,00 | — |
| 54 | steam consumption $D_k$ per cooling, kg/kWh | — | 9,28 | 7,87 | 7,45 | 7,02 | 7,10 | — |
| 55 | generator output $\eta_a$ | — | 0,868 | 0,918 | — | 0,947 | — | — |
| 56 | thermodynamic turbine efficiency (to gross work) $\eta_e$ | — | 0,52 | 0,567 | — | 0,613 | — | — |
ADDITIONS. §§ 7, 8 and 9.
the actual maximum. As the tachogram shows, the valve snapped shut \(12\frac{1}{2}\) sec. after the beginning of the turbine runaway, when the number of
Fig. 363.
r.p.m. had increased by \(7.7\%\). From this moment \(n\) immediately begins to fall, and approximately after 33 sec. the number of r.p.m. passes through the normal value.
8, p. 40, 21 from the top. A water resistance for very precise regulation at small loads can be constructed according to the proposal of the United Works Rüsch-Ganahl166) as in Fig. 364; instead of electrodes \(a,a\), trough-shaped vessels \(c,c\), covered and mounted on rods \(b,b\) and insulated from them, are immersed in a tank \(d\) with water. The vessels \(c,c\) are slightly inclined, so that running water, entering through the tubes \(e,e\) and falling onto \(a,a\), flows out of \(c,c\) over the edge, and, owing to the strong motion of the water, at first there is low electrical conductivity and low absorption of energy. With deeper immersion of the vessels \(c,c\) together with the electrodes \(a,a\), the motion of the water decreases, and the load of the generator increases.
Fig. 364.
9, p. 47, 6 from the bottom. For braking high-power turbines at a comparatively small number of revolutions it is very convenient to use a brake whose shoes are arranged radially and are pressed against the corresponding disks by water pressure; in short, this brake is a modification of the well-known Olden brake.
The construction of this brake, used by the shipbuilding yards “Vulkan,” Hamburg and Stettin, is shown in Figs. 365 and 366167): in the cylindrical cast-iron casing \(A\) there are several, in the present case 9, cast-iron disks \(B\), which can move along the axis of the shaft, but by the corresponding cut-outs on the disks and projections on the casing are prevented from rotating; the disks \(B\) are provided on both sides with end inserts of hard wood. Between the disks \(B\) rotate steel disks \(C\), carried in rotation by the shaft \(F\) through a steel sleeve \(E\) fastened to it; the disks \(C\) can also move in the axial direction along the corresponding projections on \(E\).
166) Z. V. d. I. 1912, S. 892.
167) Bauer u. Lasche. Schiffsturbinen. München. 1913, S. 383.
The pressing of the stationary and rotating disks against one another is effected by the pressure of water through the piston \(D\).
Regulation of the water pressure, i.e. of the load, is achieved by always allowing a little water to flow out of the cavity \(D\) and by manually changing the opening of either the inlet or outlet valve. The water required for cooling and lubricating the rubbing surfaces enters the opening \(G\) and is discharged through the opening in the casing \(A\).
Drawing 365 and 366.
The calculation of the absorbed work is carried out according to the expression
\[ N_e = 0.001396\, nGl, \tag{19a} \]
where \(n\) is the number of revolutions per minute, \(l\) is the length of the arm \(H\), in m., Drawing 366, from the axis to the point at which it bears upon the platform of the decimal scales, giving the reading \(G\) kg.
In Drawings 365 and 366 there is shown, approximately at \(1/50\) natural size, a brake for a ship turbine developing up to 4000 h.p. at only 200 revolutions per minute.
10, p. 51, 6 from below. In Drawing 36710, p. 302, a Sève water brake is shown during the testing of a turbine for a destroyer at the testing station of V. K. E. The measurement of the circumferential force is made, on one side visible in the drawing, by means of the tension of a spring dynamometer, and on the other side by pressure upon a hydraulic dynamometer or upon decimal scales.
Between the brake and the turbine there is placed a Föttinger dynamometer, which was thereby graduated and calibrated for the subsequent testing of the turbine after its installation on the vessel.
10, p. 60, 23 from top. On the same scheme—that of a centrifugal pump—is based the design of the Föttinger brake, Drawings 368–37011, p. 302: on the shaft \(a\), connected with the turbine being tested by means of the coupling \(l\), there is mounted the wheel \(b\) of the centrifugal pump; the cast-iron casing \(c\) hangs on the shaft \(a\) and, like the preceding designs, transmits the moment of rotation being tested to the corresponding dynamometer.
The peculiarity of the brake lies in the method of regulating the magnitude of the absorbed work: the casing \(c\) is completely filled with water circulating,
Drawing 367.
as indicated by the arrows, drawing 368; at the same time a velocity in the tangential direction is imparted to this water, so that its motion takes place properly along spirals; the water enters wheel \(b\) with a certain circumferential velocity. By means of special rotating guide vanes
Drawings 368–370.
\(d,d\), drawings 368–370, it is possible to vary the above-mentioned inlet velocity, and at the same time the quantity of circulating water; it is also possible to turn the vanes \(d\) so that the direction of motion of the entering water either coincides with, or is opposite to,
depending on the direction of rotation of wheel \(b\), Figs. 369 and 370. The blades are turned, similarly to the guide apparatus of water turbines, by rotating from outside, with a special handle, the rings \(f,f\), to which are attached cams entering the slots at the ends \(d\). In addition, the quantity of water circulating per unit time can also be varied by means of the cylindrical gates \(g,g\). The axial displacement of the gates \(g,g\) is effected by rotating, by the flywheel \(e\), both rods \(h,h\) with left- and right-hand threads.
The necessary cooling of the brake is achieved by the continuous discharge of the heated water at the lower point of casing \(c\); the loss of water is made up by inlet \(ea\) through a flexible hose near the center of the apparatus. The flow of the cooling water is regulated by hand according to the load, so that the water temperature does not exceed \(85^\circ\text{C}\).
12, p. 70, 10 from the top. In Figs. 371–373 there is shown the latest Föttinger indicator, which has a resemblance to the preceding apparatus: the kinematic linkage usual for Föttinger instruments, \(ghik\), displaces (under the influence of the rotation of rings \(d,d\) on tube \(b\) relative to rings \(f,f\) on shaft \(a\)) in the axial direction the light slide \(l\), to the flange \(m\) of which a cam on the toothed rack \(n\) can be pressed by a weak spiral spring; the relative axial dis-
Figs. 371–373.
placement ...
the movement of which is indicated by the arrow \(o\) on the scale; moreover, the same intermediate gear moves the rack \(p\), at the end of which is a pencil making a record on the diagram drum \(q\), driven in rotation by the electric motor \(r\) by means of a cord transmission. In order that the instrument should not wear out needlessly, the scale with the rack \(n\) is normally pulled a little to the left by a spring; for taking readings and making records, the scale must be moved by the handle \(w\) to the right, until the stop on the scale is pressed against the flange \(v\).
In Fig. 373 the instrument is shown opened, with the casings \(s\) removed from around the rotating rings, \(t\) from around the tube, and \(u\) from the writing device.
The remaining details of the instrument are clear from the drawings.
30, p. 172, 9 from top. It is especially difficult to obtain a correct sample of low-pressure steam, owing to the fact that in it the specific weights of the particles of steam and droplets of water differ much more from one another than in high-pressure steam.
According to the experiments of Stott and Pigott \(^{170}\), the best results are obtained with the steam take-off shown in Fig. 374: into the wall of the vertical pipe \(c\), along which the steam rises, a bent \(1/2''\) tube \(b\) is screwed, with an elbow directed toward the steam; into tube \(b\) is screwed a bronze nozzle \(a\), \(3/8''\) in diameter, with edges sharpened like a knife blade; the axis of nozzle \(a\) stands away from the wall \(c\) by \(1/6D\), the diameter of the pipe, since, according to the experiments of Stott and Pigott, at this distance from the wall the steam sample corresponds to the mean value. For the correctness of the mean sample, an indispensable condition is that the velocity in nozzle \(a\) be exactly equal to the mean velocity of the steam in pipe \(c\), i.e., that the quantity of steam being withdrawn, admitted into the calorimeter, \(g\) kg/hr, should be related to the quantity \(G\) kg/hr flowing through pipe \(c\) as the section \(f\) of nozzle \(a\) is to the section \(F\) of pipe \(c\); whence the quantity of steam taken into the calorimeter must be
\[ g = G \cdot f/F; \tag{46a} \]
the required magnitude \(g\) is attained by opening the cock \(i\) to a greater or lesser extent.
31, p. 174, 17 from top. For determining the moisture content of low-pressure steam, for example, steam entering a low-pressure turbine from a heat accumulator, Stott and Pigott developed a calorimeter of special construction, differing mainly in its considerable dimensions. The scheme and the taking of readings are identical with the Barus combined calorimeter analyzed above.
Through tube \(b\), Fig. 374, about \(1/12\) natural scale, steam enters through valve \(d\), fully opened, into the calorimeter water separator, formed of a brass tube \(e\) 100 mm in diameter; co—
\(^{170}\) Proceed. Am. Inst. El. Eng. 1910, p. 1495.
…the amount of water \(g_1\) released here is measured by the water-gauge glass with scale \(g\). The steam then passes through the adjustable cock \(i\), by which it is throttled and superheated, and, having passed along the branch \(k\) and \(l\), enters through the 1-inch pipe \(n\) into the surface condenser, after which its amount \(g_2\) is measured. Into the nipple-cup \(l\), made of a \(1/4\)-inch gas pipe, a thermometer is inserted, by which the superheat temperature \(t\) is measured, and the \(1/4\)-inch tube \(m\) connects the cavity of the calorimeter with a mercury vacuum gauge. The whole apparatus is carefully insulated against heat loss by a layer of asbestos \(f\), about 40 mm thick, except for the sight glass \(k\), which is made of \(3/4\)-inch water-gauge glass and makes it possible to judge whether all the steam has in fact been superheated owing to the soft cock \(i\); the slightest presence of moisture, sometimes observed even with superheat of \(3\div5^\circ\)C, causes internal fogging of the glass at \(k\). The second branch \(l\) from the 1-inch pipe is made so that, without increasing the diameter of the glass at \(k\), it facilitates the removal into the condenser of steam having a very large specific volume. The correction for heat emission was found to be less than \(0.10\%\), so that it may be neglected.
As careful experiments showed, the calorimeter–water separator released only \(60\div80\%\) of all the moisture; the throttling calorimeter handled moisture up to 2 and even 3% when the steam expanded from \(0.85\div1.40\) to \(0.04\div0.05\) kg/cm\(^2\) abs. The lowest steam content determined by this combined calorimeter was \(x=0.85\).
33, p. 185, 9 from top. Recently, V. I. Yasinsky has been working on the question of measuring steam consumption, having undertaken very thorough and interesting experiments on measuring steam consumption during…
with the aid of diaphragms inserted between the flanges of the steam pipe12). For the time being, thin diaphragms 5 mm thick, with sharp edges cut at \(45^\circ\) according to Fig. 309, p. 207, have been studied by them in greater detail. The data they obtained on the magnitude of the discharge coefficient \(\mu\) of these diaphragms may be summarized in broad outline as follows:
-
\(\mu\), within the range from 2 to 12 atm., does not depend on the initial steam pressure;
-
\(\mu\) depends little on the pressure drop \(\Delta p\) in passing through the diaphragm;
-
\(\mu\) depends on the temperature of the steam, on the type of diaphragm, and on its diameter;
-
in “sharp,” thin diaphragms \(\mu\) decreases rather rapidly as \(d\) is increased to 40 mm; thereafter it remains almost constant and equal: for dry saturated steam, \(\mu = 0.63\); for superheated steam, from \(t = 260^\circ\) to \(300^\circ\) C., \(\mu = 0.58\).
The accuracy attainable when using these diaphragms with a mercury differential manometer according to Figs. 375 and 376 and with the above-indicated values of \(\mu\) is about \(\pm 3\%\).
The mercury manometer must be made of glass tubes \(a\) and \(b\), tested for high pressure and secured in boxes \(c\) and \(d\) by means of stuffing boxes with hemp or rubber packing. Box \(d\) must be made of steel, while \(c\) may be bronze. Cock \(e\) connects tube \(a\) with the steam pipe up to the diaphragm, and \(f\)—beyond it; air cocks \(g\) and \(h\) serve for blowing through the apparatus; the metal manometer \(m\) indicates the steam pressure in the steam pipe. The tubes connecting the manometer with the steam pipe must be filled with water, the upper level of which must be at the same height in both of them; for this purpose one may use vessels with overflow according to Fig. 205, respectively 273 and 274.
34, p. 191, 1 from the bottom. For the same purpose—monitoring the steam consumption when feeding boilers by centrifugal pumps—one may use a Venturi water meter: into the delivery pipeline is inserted a branch pipe \(a\), Fig. 377, first narrowing and then again widening to the diameter of the pipeline. By the pressure \(p_1\) up to the apparatus and by—
to the reduced pressure \(p_2\) in the very narrowest place, its water velocity can be determined; and, knowing the area of the cross-section at this place, also its discharge per unit time. In practice the differential manometer \(d\) is graduated directly for the water discharge at some specified pressure \(p_1\). For more accurate measurements, tubes \(b\) and \(c\) may be connected to a differential mercury manometer in the form of a U-shaped tube.
35, p. 212, 1 from the bottom. In Fig. 37813, p. 308, the arrangement of all the instruments for measuring the quantity of condensate by Danaids on a turbine torpedo boat is shown: the condensate pumped out from the surface condenser \(a\) by the air pump \(b\) enters vessel \(c\), from which it flows through calibrated openings into collector \(d\) for warm water. The steam from the auxiliary machinery goes to the feed-water heaters, whence through pipes \(f\) it enters the measuring tank \(g\); \(e\) is the auxiliary air pump.
In Fig. 379 the exterior view is shown, and in Fig. 380—the section of the vessel with calibrated openings: the condensate enters the rectangular riveted tank \(a\) through pipe \(b\), passes, to steady the level, through openings in the intermediate bottom \(c\), regulated by handle \(e\) with 2 dampers \(d,d\), then past the bottom partition \(f\) and through partition \(g\) with openings enters the space from which it flows out through calibrated nozzles \(h,h\) into the drain pipe \(p\); the vertical partition \(i\) also serves to obtain a calm—
of the same level; the head height, \(H\), is measured by the water-gauge glass \(k\). On the outer wall of the tank \(a\) hangs a diagram \(m\), found experimentally, which gives, from \(H\), directly for various nozzles the corresponding flow rate \(G\) kg/hr, as well as corrections for the influence of the temperature of the condensate.
Drawing 378.
In case the size of the nozzle taken does not correspond to the measured flow rate of water, the tank is provided with an overflow pipe \(l\). For the correctness of the results the tank \(a\) must stand on a horizontal plane, which is judged by the plumb line \(o\).
Drawings 379 and 380.
In Drawings 379 and 380 an apparatus is shown for measuring up to \(100\ \mathrm{m}^3/\mathrm{hr}\).
§§ 35 and 36.
Additions.
In Figs. 381—383 three replaceable nozzles are shown, allowing \(H\) to be kept at the desired height, independently of \(G\); moreover, the instrument can operate either with 1 or with 2 nozzles; for example, in Fig. 379 the left nozzle is shown closed from the inside by a plug, tightened by a bolt and a bracket \(n\), like the manhole at the boiler.
Figs. 381—383.
36, p. 215, 2 from the top. In the parallel determination of the steam consumption from the quantity of feedwater delivered to the boiler and from the quantity of condensate pumped from the surface condenser, the second value almost always proves smaller than the first, even if all steam losses on the way from the steam boiler to the turbine are taken into account. The cause usually lies in leaks of water through imperfections in the steam boiler—in the seams, at the places where the tubes are expanded, in the blowdown valve. These leaks may amount to 10–12% of the water supplied to the boiler, sometimes even up to 20%14. This leakage can be detected and measured in the following way: the steam-admission valve to the turbine is shut, and, while maintaining normal pressure in the boiler, the fall of the water level is determined over a sufficiently long time, not less than 1 hour; if the leakage is large, then the quantity of feedwater supplied meanwhile to the boiler to keep the water level at one height is determined. When determining the steam consumption from the quantity of feedwater, the indicated check must be made both immediately before the turbine test and again immediately after it. If the leakage has increased during the test, owing to further disturbance of seams or joints in the boiler, the arithmetic mean value may be taken for the correction.
Of course, if at all possible, one should avoid working with leaky boilers, since the determination of leakage cannot be made with great accuracy, and the setting up of this test—maintaining constant working pressure in the boiler at a very small steam consumption—is not an easy matter.
For measuring the fall of the water level in the boiler, and also for maintaining it at a given constant height and, finally, for obtaining a document showing the proper feeding of the steam boiler during the test, Richard’s special instrument is very convenient and useful; in it the height of the water level is indicated on a dial by a pointer connected with a float floating on the surface of the water inside the boiler. Owing to intermediate transmissions, changes in the water level are indicated on an enlarged scale. In addition to the pointer indicator, the instrument may also, if desired, be equipped with a self-recording device.
Addenda.
36, p. 218, 14 from the top. The steam consumption by the heat balance of the condenser is determined if there are no other instruments or means. If, for example, the flow rate of the cooling water \(W\) kg/hr, its temperature \(t_1\) at entry and \(t_2\) at exit from the condenser, the condensate temperature \(t_k\), and \(i_0\), the heat content of the exhaust steam before entering the condenser, have been found from a water meter, then the steam consumption \(G\) kg/hr may be calculated from the expression
\[ G=\frac{W(t_2-t_1)}{i_0-t_k}, \tag{69a} \]
where in the case of a jet condenser \(t_k=t_2\).
However, this method may be resorted to only in an extreme case, and the result obtained should be regarded only as an approximate one, having an accuracy of no more than \(\pm 10\), and even \(\pm 20\%\).
This occurs for a whole series of reasons: 1, the relative error of the difference \(t_2-t_1\), owing to the fact that the quantities \(t_2\) and \(t_1\) are too close to one another, is very large; it may reach \(\pm 10\%\) and even be considerably greater; 2, the quantity \(G\) is obtained as the result of numerous measurements, and the individual errors accumulate; 3, the accuracy of measuring the temperatures \(t_1\) and \(t_2\) is small, especially with a surface condenser, since the outgoing water consists of streams of different temperature, usually not sufficiently well mixed; 4, the quantity \(i_0\) can be found from steam tables with sufficient accuracy only in the case of the superheated state of the steam, which, it is true, occurs\({}^{174}\), but by no means always. Since the determination of the steam moisture \(x_0\), as indicated above, is associated with large inaccuracies and complicates the entire test, for wet exhaust steam the method under discussion loses all significance.
In general, we have considered it necessary to mention it in order to point to it as a check measurement, desirable, like any check in general, and to warn against using it in important cases.
44, p. 261, 6 from the bottom. In conclusion one may cite a device that makes it possible to measure the axial force acting on a turbine shaft, according to the scheme of the torsion indicators discussed above and used in testing marine turbines for measuring the axial pressure produced by the propeller.
Fig. 384\({}^{175}\) shows the scheme of the device: between the driving end of the shaft \(a\) and the driven end \(b\) disk couplings \(c,d\) are inserted, which, under the action of an axial force, give a small but measurable axial displacement of \(a\) relative to \(b\). To measure the tensile force from \(a\) to \(b\), for example, when the vessel is moving astern, the disks \(c,d\) must—
\({}^{174}\) See, for example, the test of the turbine by Melms and Pfenninger, Z. V. d. I. 1906, p. 1865.
\({}^{175}\) Bauer u. Lasche. Schiffturb. S. 400.
§ 44. Additions.
must be fastened to the circumference by suitably arranged bolt fastenings. It is understood that the couplings \(c,d\) at the same time also transmit the torque, but, with their large diameter, the elastic deformations in torsion are imperceptibly small.
The deflections of the disks must be small, so as not to produce inadmissible stresses in the material; in view of this, the instrument is composed of several pairs of disks, the deflections of which are added together and, magnified by the corresponding lever transmission, are measured after the manner of Föttinger’s indicator.
Fig. 384.
The magnitude of the deflection of the disks can be computed in advance, but nevertheless it is more reliable to carry out the graduation directly by experiment, using for this purpose a hydraulic dynamometer.
In Fig. 385 there is shown the construction of such an instrument with one pair of disks of large diameter; the relative displacement
Fig. 385.
of the bushings \(c\) and \(d\) is transmitted through the mediation of the levers \(c f g\) to the light bushing \(h\), against the left collar of which the cam \(i\) is pressed; the displacements of the latter from 0 are transmitted by the rack connected with it and by the pinion \(k\) to the pointer \(l\). During the reading the indicating device is pressed to the right by the handle \(m\); at other times it is kept out of contact with \(k\) by a spiral spring, which draws it to the left by means of the tongue \(n\); \(o,o\) is the casing by which the rotating parts of the instrument are enclosed.
Appendix 1.
Rules for Testing Steam Turbines1).
I. Introduction.
The proposed rules are intended to give general instructions for testing steam turbines.
It is necessary to enter in the records not only the results of the investigations, but also the principal data of the tested installations, as well as the circumstances under which these results were obtained. Then the results of the investigation could be used not only in the given individual case, but would acquire general significance. For this it is necessary that all instructions be given uniformly, in accordance with the rules set forth below.
The conduct of tests should be entrusted only to such persons as possess the knowledge and skill necessary for this purpose. They must develop a test plan in accordance with the goal pursued, since in many cases it is not required that the investigations indicated below be carried out in their entirety; they must then verify the accuracy of all instruments used in the test and process the results of the investigation. The work must be based on the rules given below, and in each individual case only those of them should be selected that correspond to the objectives of the test.
II. Principal provisions of the contract.
1) In order, as far as possible, to eliminate misunderstandings in setting up experiments and in evaluating the results obtained, it should be strongly recommended that the supply contract stipulate not only the guarantees, but also the method for verifying these guarantees, taking into account the particular features of the installation and being guided by the proposed rules.
2) In general, the contract should mention only those guarantees that can be verified directly, i.e., the guarantees should apply only to measurable quantities. Therefore one should carefully avoid vague or difficult-to-define concepts; for example, the expressions “maximum load,” “short-time overload” should be used only together with an indication of the exact time and magnitude of the permissible load, overload, etc.
3) In a contract for the supply of a steam turbine, it is recommended to specify guarantees of steam consumption for several (but not fewer than two) loads, one of which should, if possible, be close to the load expected during acceptance tests. Further, the contract should include indications of:
a) the state of the steam before the turbine2) (pressure and temperature with superheated steam, and with saturated or wet steam);
b) the steam pressure in the exhaust pipe, or the temperature and quantity of cooling water, if a condenser is installed together with the turbine;
c) the method and place of the test.
1) From the rules drawn up for steam piston engines and turbines and adopted by the 2nd All-Russian Congress on Mining, Metallurgy, and Machine Building; the author has made changes relating only to steam turbines.
2) Italics indicate words inserted by the author when adapting the general rules especially for the testing of steam turbines.
In cases where superheated steam is used, the guarantee should be stated for several different superheat temperatures, or else the method should be stipulated for recalculating the consumption of steam or heat in the event of deviations from the stipulated temperature.
It is also recommended, for steam turbines, to stipulate the method for recalculating the steam consumption in cases where the vacuum or the temperature of the cooling water deviates from those stipulated in the contract.
5) If the boiler and machine installation is manufactured by one and the same supplier, then the guarantee may be expressed in terms of fuel weight, or in units of heat contained in the fuel, consumed per unit of machine power. However, the actual superheat temperatures must be specified and must correspond to those temperatures which form the basis of the guarantees for the turbine.
6) The contract should stipulate the magnitude of the permissible deviations from the guaranteed figures at which the guarantee is still considered fulfilled. This condition is intended, as far as possible, to take into account the inevitable errors of observation and inaccuracies in the conduct of tests; they must therefore be evaluated in relation to the subject and purpose of the investigation. Thus, for example, in guarantees of fuel consumption larger deviations are permitted than in guarantees of steam consumption. These deviations must be stipulated in the contract in direct connection with the guaranteed figures. If such tolerances are not specified in the conditions of supply, then, in assessing the results of the test, no deviations are allowed.
7) When delivering an installation or parts thereof, the supplier must see to it that all measuring instruments provided for in the present rules can be installed as easily as possible and in the proper places; that is, the necessary nipples, sleeves for thermometers, control flanges, etc. must be provided, or the corresponding openings must be prepared at the extreme points.
8) It should be recommended that the period during which, or after which, the acceptance tests are to be carried out be specified, and also that the work which the supplier has the right to perform immediately before the acceptance tests be stipulated, with a period indicated for such work; in doing so, the operating conditions of the installation must be taken into account.
Note. In the case of a small turbine of an established type, it is of course desirable both for the supplier and for the purchaser to see it accepted as soon as possible. In the case of the supply of a large turbine, built according to a new model or with adaptations for special purposes, it is necessary to give the supplier a longer period, so that the turbine may run in under his supervision and so that he may eliminate any defects that become apparent. It is also highly desirable for the purchaser to have sufficient time to become well acquainted with the turbine before assuming full responsibility for it. On the other hand, any alteration of the turbine entails inevitable interruptions in its operation, and therefore the purchaser has the right to wish to obtain, as soon as possible, a turbine operating without defect.
It is not rare for the acceptance tests not to be specified in the conditions and therefore not to be carried out; and then, when the purchaser has used the turbine independently for a sufficiently long time, various misunderstandings arise as to its condition. In the event of such an agreement, by mutual consent, a test of the turbine is carried out; but before beginning the final test it is necessary to give the supplier some period of time to examine the turbine and to allow him to correct the defects that became apparent during the turbine’s period of operation.
III. General rules.
A. Subject of investigation.
9) The subject of the test may be:
A) For steam turbines:
a) the condition of the working steam (its pressure, temperature, or moisture content);
b) the number of revolutions;
Appendix 1.
c) power (work);
d) steam consumption per hour per unit of power;
e) steam consumption (if the drive is furnished by a separate auxiliary machine) or electrical energy for driving the auxiliary mechanisms;
f) quantity and temperature of the cooling water;
g) fluctuation of speed under constant load and change of the mean number of revolutions under a sudden or gradual change of load;
h) consumption of lubrication;
i) temperature and consumption of water for cooling the oil.
Note. Since in the vast majority of cases steam turbines operate in direct connection with some working machines (dynamo, pump, compressor, etc.), determining their effective work is usually very difficult. On the other hand, the indicated work of a steam turbine is a concept altogether relatively remote, not subject to direct measurement. Therefore, in the conditions for the supply of steam turbines the guarantee of steam consumption is usually referred to a unit of work of the driven mechanism (for example, per 1 kW per hour, per 1000 cubic meters per hour of air or water delivered at a given pressure difference or at a delivery height in meters, etc.).
The lubrication of the main bearings of steam turbines is usually arranged so that the oil circulates continuously and is filtered and cooled along the way. Therefore the consumption of lubricant is usually very small, and its determination presents great difficulty and in any case requires a very long observation time. As regards the consumption of lubricant for the secondary parts of the turbine, its determination cannot present difficulties.
b) Kind, number, and duration of tests; permissible deviations.
10) The kind, number, and duration of tests are determined by the purpose of the test and must be selected and stipulated in advance in accordance with the terms of the contract and the operation of the installation. In tests, however, that are of special importance, when their results have decisive significance—for example, for acceptance, penalty, or bonus—in accordance with the extent of the interest connected with this.
11) Kind of tests. For a turbine it is necessary to arrange tests without interruptions; this is easy to do in installations which operate at least 8–10 hours continuously under an almost uniform load; in the opposite case such operation must be produced artificially.
12) In determining steam consumption by measuring the quantity of feedwater supplied to the boiler, the test must continue continuously for 8 hours, or, under a completely uniform load, at least 6 hours. In each test at least one complete intermediate report (record) must be made; however, the results of an intermediate report must in no case be taken as the results of the whole test.
Note. At the moments of intermediate reports the test should be conducted as at the end of any independent test, i.e., by this moment the water level in the boiler, the pressure, etc., must be brought to the initial state, and all readings must be taken, not excluding the consumption of steam or fuel. In this way, the time between intermediate reports represents as it were two independent tests directly following one another. Only the results of such intermediate reports should in no case be treated independently as the result of the whole test.
In determining the steam consumption by the boiler, a fairly considerable inaccuracy is unavoidable in bringing the water level in the boiler to the same height at the beginning and at the end of the test. To reduce the relative significance of this error, it is desirable to conduct the test for as long as possible; on the other hand, a duration of tests of more than 8 hours often entails great difficulties of an operational character. Therefore this paragraph should in any case serve to avoid overly short tests, in which the principal inaccuracy of observing the water level in the boiler has a substantial effect, while leaving full freedom to management to set longer tests where this is necessary and possible.
An error in observing the water level in the boiler is especially strong when there is a significant discrepancy in the sizes of the boiler and of the turbine being tested, for example, if the steam consumption of a small turbine is determined by measuring the feedwater of a large boiler. Therefore it is highly desirable that when
...for testing a turbine under full load, the heating-surface load of the boiler approached that normal for the given system. If it is impossible to fulfill this condition, the experiment must be made longer, so as to reduce the relative value of the error.
13) If the quantity of expended steam is determined by means of a surface condenser, then, when the operating condition is steady, a shorter experiment is sufficient; its duration is determined according to the fluctuations of the load. With a uniform load it is sufficient to conduct such experiments for one hour.
15) In order to study the installation in operation, to test all the devices necessary for the experiments, and to train the observers and assistants, it is recommended to carry out preliminary tests. They should be carried out immediately before the principal experiments. Their duration is to be chosen in accordance with the circumstances.
Note. In general, it is undesirable to introduce preliminary experiments as a rule, since this increases the already considerable cost of the tests even without them. Therefore the expert should resort to them only in case of necessity; the supplier, however, must not be deprived of the possibility of conducting preliminary tests before acceptance.
16) During tests of special importance, in addition to the preliminary experiments, two principal experiments should also be performed, one after the other. The mean of the results of these two principal experiments, if they differ by no more than 5%, is taken as the result of the test. However, the mean of the principal and preliminary experiments must not be taken.
Note. The usefulness, in certain cases, of check experiments cannot in general be denied, but they are entirely useless when there is sufficient accuracy in the agreement of the intermediate readings. And since, moreover, check experiments make the test considerably more expensive, they should be resorted to only in cases of extreme necessity.
17) During the experiments, in the steady state, fluctuations in the load must not exceed $\pm 15\%$.
18) If the average load of the experiment differs from that relative to which the guarantee is given, then the comparison is made by means of interpolation. In this case, unless there are special instructions in the contract, the total steam consumption of the turbine is interpolated linearly.
If, in the contract, a guarantee is given only for one load, then it is assumed that the same guarantee must be fulfilled for deviations of the load by $\pm 7.5\%$. Tolerances are taken into account only when they are stipulated in the contract (see § 6). Other corrections for deviation from the guaranteed condition of the steam, vacuum in the condenser, etc., if they are not stipulated in the contract, should be agreed upon before the beginning of the tests. If the required corrections can be determined on the basis of the experiments carried out, then precisely these experimental corrections are taken in the calculation, even in the case when those stipulated in the contract differ from them.
19) During acceptance and all experiments serving to clarify misunderstandings between the supplier and the customer, the presence and participation in them of both the supplier and the customer, or of their authorized representatives, is always desirable.
B) Units of measurement and designations.
20) All dimensions must be indicated in metric measures.
21) Temperature measurements are made with a 100-degree thermometer (Celsius); quantities of heat are expressed in kilogram-calories.
22) When indicating pressures it is always necessary to state what pressure is meant: absolute, excess pressure (manometric), or rarefaction (vacuum). If such indications are absent, then by steam pressure is always meant excess pressure above atmospheric.
Appendix 1.
Pressures less than atmospheric are designated as vacuum (vacuum) and may be expressed in millimeters of water (= 1 kg per sq. m.) or mercury column. By vacuum is meant the difference between barometric (atmospheric) pressure and the pressure being measured.
The unit of pressure and vacuum is taken to be the metric atmosphere, i.e. the pressure of 1 kg per 1 sq. cm.
23) The mechanical equivalent of heat is taken equal to: 427 kg-m = 1 unit of heat (1 kilogram-calorie), and accordingly the thermal equivalent of 1 hp-hour is equated to 632 units of heat.
24) As the unit of measure for the power of a steam engine, 1 kilowatt = 102 kg-m per sec. is considered, or horsepower equal to 75 kilogram-meters per second = 0.736 kilowatt (1 kW = 1.36 hp). It must always be indicated whether the indicated, useful, electrical, or other work of the machine is meant; if no such indication is given, then it is always understood to mean the useful work on the shaft of the machine, less the work of all mechanisms required for it, if these are driven by independent machines.
The steam consumption in turbo-generators is always referred to the kilowatt.
28) In determining the quantity of heat of the steam consumed, the full heat of it before entering the machine is taken into the calculation (according to the latest data, e.g., the Mollier diagrams or tables).
IV. Conduct of Tests.
29) The type, number, and duration of tests are selected in accordance with §§ 10—18.
30) At the beginning and at the end of each test all conditions must be entirely identical: the turbine and the boiler serving it must remain throughout the entire experiment in the steady state that has been established.
31) In determining steam consumption, all non-working steam and water pipes must be disconnected from the turbine under test, its condenser, and from the boiler serving the turbine, if measurements are made at the boiler. This is best done by means of plugs, which should be installed, as far as possible, closer to the boiler, turbine, or condenser.
32) In general, all observations and readings must be made no less frequently than every twenty minutes; if during the tests rapid and significant fluctuations in load or in other observed quantities may be expected, or if it is necessary to obtain especially accurate results, then it is recommended to make all readings still more often.
In the test log, along with the mean values, the greatest and the smallest values of the observed quantities should also be indicated.
33) All measuring instruments and vessels must be accurately and reliably calibrated.
34) The test log must indicate the design of the installation and the conditions of its operation; this must be explained by the corresponding drawings so fully that it is possible to judge correctly the method of operation and the results of the experiments. In particular, for comprehensive tests these indications must contain the following data:
a) the system of the turbine and the conditions of its operation; description and drawings of its principal parts; number of stages, number of pressure stages and speeds; necessary dimensions;
b) the mean normal number of revolutions; permissible fluctuations thereof;
c) the pressure and temperature at which the turbine is to operate, and the highest pressure and temperature for which it was built;
g) the operation (power) for which the steam consumption is guaranteed, the guaranteed maximum power, and the permissible duration of overload;
d) the construction and dimensions of the condenser and its pumps; the method of driving the pumps; the method of obtaining the cooling water; the length and diameter of the steam-exhaust pipes;
e) the temperature and quantity of cooling water stipulated in the contract, and the vacuum corresponding to these data;
zh) the steam consumption, or the consumption of electrical energy, stipulated in the contract for auxiliary mechanisms;
z) the system and heating surface of the steam boiler serving the turbine and of the superheater, the method of feeding it; the location and size of the water separators, the length and diameter of the steam-line pipes.
(Point “z” is especially important in determining steam consumption by measurements at the boiler.)
i) the arrangement of the lubricating devices;
i) the consumption of water for cooling the oil and its temperature at inlet and outlet.
35) Before the test, the soundness of the installation must be checked. When measuring steam consumption at the boiler, special attention must be paid to the tightness of the feed pipes and steam lines; when measuring by the surface condenser, attention must be paid to the tightness of the condenser with respect to the admission into it of cooling water through leaks in the tubes and from the expansion joint of the steam-exhaust pipe. For the latter test it is best, if possible, before admitting steam into the turbine and after stopping it, to start the condensate pumps and make sure that no cooling water is being pumped out of the condenser. If leakage of the condenser is discovered, the magnitude of the leakage is taken into account when calculating the steam consumption.
36) The test must not begin before a steady state with respect to pressures and temperatures has been established in the turbine and in the measuring instruments. If the test is carried out at the usual factory load during the whole day, then the first and the last half-hour must be excluded from the time of the test proper.
37) The steam pressure, the load of the turbine, the superheat temperature, and the vacuum during the test must be maintained, as far as possible, unchanged; if necessary, uniformity of load must be achieved by artificial means (see § 17).
38) The pressure, temperature, and moisture content of the working steam, which are significant for evaluating the turbine, must, as far as possible, be measured directly before its entry into the place for which it is intended to calculate the heat delivered by the steam to the turbine; in regulation by throttling, the state of the steam is determined before the regulating valve. The pressure and temperature of the exhaust steam are determined in the exhaust pipe, immediately after leaving the last stage of the turbine.
Note. Determination of the moisture content of steam by means of throttling calorimeters, e.g. of the Pibodi type, gives sufficiently correct results when the steam moisture is small (3–5%), but in doing so it is recommended to take a sample of steam at various points of the cross-section of the jet, since the moisture content of the steam may be unequal at different points of the specified cross-section of the jet. Incomparably better and more reliable is to ensure good drying of the steam by installing before the turbine water separators of sufficient size, which at normal velocities give practically almost dry steam (moisture less than 1/2%).
39) An accurate determination of the actual (useful) power is possible only with the aid of a brake or a dynamometer; the principal dimensions and other data of the instrument must, if possible, be determined before the test. But this method is difficult to carry out for large turbines and therefore is used only in exceptional cases.
Appendix 1.
If an electric-current generator is directly coupled to the turbine, then the useful work of the turbine can be calculated with great convenience from the load of the generator. The efficiency of the generator is determined by one of the methods established in the “Standards for the Testing of Electrical Machines and Transformers” of the All-Russian Electrotechnical Congresses.
The efficiency of the belt drive, unless it is specified in the contract, is taken to be equal to 96–97%.
Note. Sometimes turbines are subjected to braking tests at the manufacturer’s test station. In that case the useful power of the machine can be determined accurately there, if necessary, when it is known in advance that this cannot be done at the site of the final installation.
44) The number of revolutions of the turbine is determined by a counter, the readings of which are recorded at definite intervals of time, or directly by reading a tachometer, which must first be checked.
45) At various intervals of time, and in any case not less often than every 20 minutes, the following must be recorded: the water level and pressure either in the boiler or immediately after the superheater (in measurements at the boiler); the pressure and temperature before and after the regulating valve in steam turbines; the pressure in the exhaust pipe and in the condenser; in addition, the temperature and, if possible, the quantity of cooling water and the temperature of the condensate flowing out of the condenser. The barometer reading and, in the case of the use of a cooling tower, the temperature and humidity of the air should be recorded several times during the test and at least at its beginning and end.
Note. All temperatures should be measured in the stream of the flowing steam, and the installation of thermometers in dead corners, where stagnation may occur, should be avoided.
46) In measurements at the boiler, the steam consumption is determined by weighing the water feeding the boiler, or by another reliable method specified in the contract; in the latter case the measuring instrument must be calibrated by weighing at the temperature of the feed water.
Note. Slight deviations in the water level and in the steam pressure in the boiler by the end of the test, if they cannot be avoided, must be included in the calculation according to their heat value, in accordance with the pressures at the beginning and at the end of the test. In doing so, attention must be paid to the fact that, if corrections cannot be avoided, they should preferably be referred to the water level, and particular care should be taken to ensure equality of pressures at the beginning and at the end of the test.
Special attention in this respect is required by water-tube and other boilers with a strongly fluctuating water level, in which, owing to circulation during steam formation, the water level appears considerably higher than the actual one.
The feeding of the boiler must be carried out uniformly and, if possible, continuously; if continuous feeding is impossible, feeding during the 5 minutes before the start of the test and 5 minutes before its end should be avoided.
For feeding the boiler it is undesirable to use steam pumps which receive steam from the same boiler as the turbine being tested, or exhaust steam from which comes into direct contact with the feed water (as, for example, in injectors), even if the steam consumption of this pump can be determined accurately.
All water leaking through the joints of the fittings, as well as that discharged during blowing down, must be carefully collected and taken into account. Water condensing in the steam piping must be collected before it enters the turbine and must be deducted from the feed water. Water condensing in the chambers of the steam turbine is included in the steam consumption of the turbine itself and must, if possible, be measured separately at each point of discharge.
Note. Devices for collecting condensation water must be arranged so that losses of it through evaporation into the air are eliminated; for this purpose the water must be cooled in these devices at least to 40°.
47) The determination of the steam consumption by means of the surface condenser is carried out by measuring the steam condensed in it, by weighing the condensate or by another reliable method. The quantity of water condensing in the turbine itself must be determined as indicated in the preceding §.
Note. There is no doubt that determining the steam consumption by means of the surface condenser gives far more accurate and reliable results than measuring it by the quantity of feed water; and the experiment itself in this case can be much shorter. It should therefore be strongly recommended to use this method in all cases where this is possible.
48) The determination of the steam consumption by means of steam meters, graduated nozzles, etc., is permissible only in the case where these instruments have been reliably calibrated immediately before the test.
49) In investigating the conditions of motion of the turbine, the following may be determined:
a) the number of revolutions of the turbine under steady motion during the greatest normal load and at no load;
b) fluctuations of the angular velocity at constant load;
c) the increase or decrease in the number of revolutions of the turbine under an artificially sudden or gradual loading and unloading of the turbine; in this case the greatest, least, and steady readings of the tachometer are recorded, if no recording tachograph is used during the test, as well as the time at the expiration of which the turbine has reached the steady state.
Note. These measurements may be made with the aid of the Horn tachograph.
d) the limiting number of revolutions at which the safety regulator begins to operate. This test is carried out with the main regulator disconnected and therefore requires special caution.
Appendix 2.
Selection of Instruments
Wishing to facilitate the selection of measuring instruments for establishing proper control over the operation of steam installations, the author has decided to provide, in Table 17, a list of the better-known firms supplying measuring instruments.
In practice, when selecting the appropriate instrument, one often has to take its cost into account; therefore the following Table 18, which indicates from which firms the corresponding instrument may be obtained, is supplemented by an indication of average, approximate prices for preliminary consideration. More detailed and accurate information may be obtained by anyone by requesting it or a catalogue from the corresponding firm.
Table 17.
| No. in order | Name of firm | Address | Representatives in Russia No. |
|---|---|---|---|
| 1 | AEG—Allgemeine Elektricitäts-Gesellschaft | Berlin N. W. 40, Friedrich Karl-Ufer 2/4. | 75 |
| 2 | Alig & Baumgärtel, Werkzeugfabrik | Aschaffenburg. | — |
| 3 | Amsler, Gebrüder | Schaffhausen, Schweiz. | — |
| 4 | Baer & Co, Henri | Zürich 1., Schweiz. | — |
| 5 | Bolte, Otto | Hamburg 19, Bismarckstr. 50. | — |
| 6 | Boston Talking Machine Co. | Boston (Mass.) U. S. A. | — |
| 7 | Brady & Martin, Ltd. | Newcastle-upon-Tyne, Northumberland-road, England. | — |
| 8 | Braun & Co., Paul | Berlin N. 112, Seelowerstr. 6. | — |
| 9 | Bretagnes, Usines de | Nantes, France. | — |
| 10 | Bristol Company | Waterbury, Conn., U. S. A. | — |
| 11 | Cambridge Scientific Instrument Co, Ltd. | Cambridge, Carlyle Road, England. | — |
| 12 | Chemische Fabrik Rhenania, A.-G. | Aachen. | 76 |
| 13 | Deuta-Werke, G. m. b. H. | Berlin SO. 26, Oranienstr. 25. | 94 |
| 14 | Deutsche Rota-Werke, G. m. b. H. | Aachen. | — |
| 15 | Deyrolle, Les fils d’Emile | Paris, 46, rue du Bac, France. | — |
| 16 | Dobbie Mc. Innes, Ltd. | Glasgow, 57 Bothwell Street, England. | — |
| 17 | Dreyer, Rosenkranz & Droop, G. m. b. H. | Hannover, Leisewitzstr. 4. | — |
| 18 | Eckardt, J. C. | Stuttgart-Cannstatt, Pragstr. 72/74. | 72 |
| 19 | Edgecombe, F. T. | Dumbarton, Kirklea, Cardross Road, England. | — |
| 20 | Farbenfabriken vorm. Friedr Bayer & Co. | Leverkusen b. Mülheim (Rhein). | — |
| 21 | Felten- & Guilleaume-Lahmeyerwerke, A.-G. | Frankfurt a.M. | — |
| 22 | Garvens, W., Commandit-Ges. für Maschinen-Fabrikation | Wülfel vor Hannover. | — |
| 23 | Gehre-Dampfmesser-G. m. b. H. | Berlin N. 31, Brunnenstr. 156. | 82 |
| 24 | Goessmann, Arthur | Berlin-Britz. | — |
| 25 | Grefe, Maschinenfabrik, Ludwig | Lüdenscheid i. W. | — |
| 26 | Hallwachs & Co., G. m. b. H. | Burbach Saarbrücken. | 80 |
| 27 | Hartmann & Braun, A.-G. | Frankfurt a.M. | 84 |
| 28 | Heenan & Froude, Ltd. | Worcester, England. | 73 |
| 29 | Heraeus, W. C., G. m. b. H. | Hanau (Main). | 85 |
| 30 | Homann, Hans | Jena, Karl-Zeissstr. 12. | — |
| 31 | Hommel, H., G. m. b. H. | Mainz. | — |
| 32 | Horn, Dr. Th. | Leipzig-Grosszschocher. | — |
| 33 | Hugershoff, Franz | Leipzig; Carolinenstr. 13. | 72 |
| Junkers & Co. | Dessau. | 93 |
Selection of Instruments.
| Order No. | Name of firm | Address | Representatives in Russia No. |
|---|---|---|---|
| 35a | Blohm u. Voss, Schiffswerft | Hamburg-Steinwärder. | — |
| 35 | Kegler, Emil, Wassermesserfabrik | Düsseldorf-Eller. | — |
| 36 | Keiser & Shmidt, | Charlottenburg 2, Charlottenburger Ufer 53/54. | — |
| 37 | Kelvin & James White, Ltd., | Glasgow, England. | — |
| 38 | Krupp, Friedr., A.-G., Germaniawerft | Kiel-Gaarden. | 73 |
| 39 | Laird & Co., Ltd. | Camell, England. | — |
| 40 | Mailak, H., A.-G. | Hamburg 39, Geibelstr. 54. | 82 |
| 41 | Munro, R. M., | London, South Tottenham N, 103 Cornwallroad, England. | — |
| 42 | Negretti & Zambra | London, 38 Holborn Viaduct E. C., England. | — |
| 43 | Nestler, Albert, Massstabfabrik | Lahr (Baden). | — |
| 44 | Neumann, F. A. | Eschweiler, Kr. Aachen. | — |
| 45 | Peerboom & Schürmann | Düsseldorf, Hoffeldstr. 88. | — |
| 46 | Polikeit, Paul, Institut für Präcisionsmechanik | Halle a. S. | — |
| 47 | Reichling & Co., Robert, | Dortmund u. Königshof bei Krefeld. | — |
| 48 | Rheinische Tachometerbau-Ges. m. b. H. | Freiburg (Baden). | — |
| 49 | Richard, Succ-r, Jules, | Paris, rue Mélingue 25, France. | — |
| 50 | Schäffer & Budenberg, G. m. b. H. | Magdeburg-Buckau. | 92 |
| 51 | Schenck, Carl, G. m. b. H., Maschinenf. | Darmstadt, Landwehrstr. 55. | — |
| 52 | Schilde, Benno, Maschinenfabrik | Hersfeld (H.-N.) | — |
| 53 | Schuchardt & Schütte, | Berlin C., Spandauerstr. 59/63. | 95 |
| 54 | Schultze, G., A., | Berlin-Charlottenburg. | — |
| 55 | Schumacher, W-we Joh., G. m. b. H., Maschinenfabrik | Köln (Rhein), Bayernstr. 57. | — |
| 56 | Siebert & Kühn, Dr., | Cassel. | 85 |
| 57 | Siemens Brothers, Ltd. | London, Caxton House, Westminster, S. W., England. | 87 |
| 58 | Siemens & Co., Gebrüder, | Charlottenburg. | 87 |
| 59 | Siemens & Halske A.-G., Wernerwerk, | Berlin-Nonnendamm. | 87 |
| 60 | Sommer & Runge, | Berlin SW. | 77, 83, 90 |
| 61 | Steinle & Hartung, Maschinenfabrik | Quedlinburg. | — |
| 62 | Spindler & Hoyer | Göttingen. | — |
| 63 | Steinmüller, L. u. C., Dampfkesselfabrik | Gummersbach (Rhld.). | 76 |
| 64 | Sulzer, Gebrüder, | Winterthur, Schweiz. | — |
| 65 | Suyehiro, Dr. K., | Tokyo, Imperial University, Japan. | — |
| 66 | Thoren, J., | Charlottenburg 4, Goethenpark. | — |
| 67 | Vereinigte Fabriken für Laboratoriumsbedarf, G. m. b. H. | Berlin N., Scharnhorststr. 22. | 83 |
| 68 | Vulkan-Werke, A.-G. | Hamburg; Stettin. | — |
| 69 | Westinghouse Co. | Pittsburgh (Pa.), U. S. A. | 79 |
| 70 | Weston Electrical Instrument Co. | Berlin, Schoeneberg, Geneststr. 5, | — |
| 71 | Wichmann, Gebrüder, | Berlin NW. 6, Karlstr. 13. | — |
| Order No. | Name of firm | Address | Representatives of foreign firms No. |
|---|---|---|---|
| 72 | Brandt and Co., trading house | Moscow, Myasnitskaya 13. | 18 |
| 73 | Weber and Co., F., trading house | Moscow, Varvarka 11. | 28, 38 |
| 74 | Worthington, Pump Co., | St. Petersburg, Kirpichnyi Lane 1; Moscow, Myasnitskaya, Kabanov house. | — |
| 75 | V. K. E.—General Electricity Company | Moscow, Lubyansky Passage, Stakheev house. | 1 |
| 76 | Hilger, Otto, | Moscow, Myasnitskaya 24. | 12, 63 |
| 77 | Gukersgof, Franz, Joint-Stock Company, | Moscow, Sretenka 10. | 33, 60 |
V. L. Matveev—Testing of Steam Turbines.
Appendix 2.
| No. in order | Name of firm | Address | Represent. foreign firms No. |
|---|---|---|---|
| 78 | Dangaouer and Kaiser, | Moscow, Myasnitskaya 24. | — |
| 79 | “Dinamo,” Russian Electr. Soc., | St. Petersburg, Fontanka 86; Moscow, Myasnitskaya 13. | 69 |
| 80 | Knopp, L., etc. | Moscow, by the Ilyinsky Gates, bldg. of the Merchant Bank. | 26 |
| 81 | Kraminsky, A., | St. Petersburg, Kronverksky Ave. 77/79. | — |
| 82 | Langensiepen & Co., Joint-Stock Soc., | St. Petersburg, Kamennoostrovsky Ave. 11; Moscow, Myasnitskaya 3. | 23, 40 |
| 83 | Luntz, Dr. O. G., | Moscow, Kuznetsky Most 15; St. Petersburg, Kazanskaya 6. | 60, 67 |
| 84 | Neese, F. N., | St. Petersburg, M. Konyushennaya 12. | 27 |
| 85 | Pikersgill & Co., P. A., etc. | Moscow, Middle Trading Rows 178/179. | 29, 56 |
| 86 | Plushevsky, heirs of L. I., | Moscow, Chistoprudny Boulevard 10. | — |
| 87 | Siemens & Halske, Joint-Stock Soc. | St. Petersburg, English Embankment 10. | 57, 58, 59 |
| 88 | Technical-Industrial Bureau | Tomsk, Ushaika Embankment. | 40 |
| 89 | Trek, G. A., | St. Petersburg, Galernaya 8. | — |
| 90 | Trinity Sv-ya, E. S., | Moscow, Lubyanka, own house. | 60 |
| 91 | Frantsen, mechanic, | St. Petersburg, V. O., physics laboratory of the university. | — |
| 92 | Schaeffer and Budenberg, | Moscow, Milyutinsky Lane 3. | 51 |
| 93 | Shirel, K. G., | St. Petersburg, Karavannaya 18. | 34 |
| 94 | Shmed, N. S., | St. Petersburg, Kamennoostrovsky Ave. 57. | 13 |
| 95 | Shukhardt and Schütte, | St. Petersburg, Nevsky Ave. 11. | 54 |
| 96 | Erikson, R., | Moscow, Myasnitskaya 20; Ivanovo-Voznesensk, Nikolaevskaya St., Sokolov’s house; St. Petersburg, Nevsky Ave. 92; Kharkov, Donets-Zakharyevskaya 5. | — |
Table 18.
| Name of instrument | Page | Plate | Cost, rub. | Nos. of firms from Table 17 |
|---|---|---|---|---|
| Hand revolution counter with worm | 1 | 1 | 4 ÷ 6 | 2, 4, 16, 17, 40, 45, 49, 50, 53, 82, 88, 92, 95 |
| ” ” ” ” with toothed wheels | 2, 4 | 3—6 | 7 ÷ 16 | 16, 17, 40, 45, 50, 53, 82, 88, 92, 95 |
| Tachoscope | 2 | 2 | 48 | 40, 82, 93 |
| ” with dials arranged in rows | 3 | — | 75 | 53, 82, 95 |
| Stopwatch | 3 | — | 20 ÷ 40 | 40, 53, 82, 95 |
| Revolution counter connected with a tachometer | 5 | 7 | 80 ÷ 120 | 13, 32, 40, 45, 53, 94 |
| Tachometer with weights (pendulums) | 7 | 8—9 | 50 ÷ 90 | 4, 13, 32, 45, 48, 53, 94 |
| ” ” ” ” | 8 | 10—12 | 40 ÷ 135 | 50, 82, 92 |
| ” ” ” by Opyud | 8 | 13 | 40—100 | 4 |
| Bifilar tachometers | 9—10 | 16—17 | 50 ÷ 90 | 48 |
| Tachometer with oil pressure | 11 | 18—19 | by special estimate | 64 |
| ” magneto-electric | 12 | 20 | 45 ÷ 75 | 13, 50, 92, 94 |
| ” electric | 13 | — | 300—350 | 32, 59, 87 |
| Resonance tachometer | 13 | 25 | 40 | 59, 87 |
| ” ” with transmission to a distance | 14 | 26—29 | 60 ÷ 150 | 59, 87 |
| ” ” ” ” ” | 16 | 30 | 55 ÷ 70 | 59, 87 |
| ” ” with electric indicator | 16 | 31—32 | 100 ÷ 200 | 27, 59, 84, 87 |
| Hand tachometer with pendulums | 19 | 33 | 30 ÷ 65 | 13, 32, 40, 45, 48, 50, 53, 82, 92, 94, 95 |
| ” ” ” ” | 20 | 34—35 | 45 ÷ 65 | 45 |
| ” ” ” ” | 21 | 36 | 40 ÷ 80 | 32 |
Selection of Instruments
| Name of instrument | Indicated: p. | Indicated: fig. | Cost, rub. | Nos. of firms from Table 17 |
|---|---|---|---|---|
| Hand tachometer with eddy currents | 22 | 38–39 | 40÷60 | 13, 94 |
| Device for switching on the tachometer | 22 | 37 | by special order | 32 |
| Recording tachometer | 24 | 40 | 120÷300 | 13, 32, 40, 45, 82, 94 |
| ” ” ” hand | 24 | 41 | 90–100 | 32, 40, 82 |
| Horn tachograph | 25 | 42–45 | 250÷600 | 32, 40, 82 |
| ” ” with clock mechanism | 28 | — | 260 | 32, 40, 82 |
| Oscillograph | 33 | — | 930÷1200 | 59, 87 |
| Ammeter | 36 | — | 30÷200 | 27, 32, 59, 70, 81, 84, 87, 88, 89, 96 |
| Voltmeter | 36 | — | 40÷120 | 27, 32, 59, 70, 81, 84, 87, 88, 89, 96 |
| Wattmeter | 36 | — | 120–360 | 27, 32, 59, 70, 81, 84, 87, 88, 89, 96 |
| Band brake up to 30 h.p. | various | 61 | 160÷300 | 46 |
| ” ” self-regulating up to 30 h.p. | — | — | 160÷300 | 46 |
| Spring dynamometers for brakes, belt and water | — | — | 5÷175 | 3, 46, 49, 52, 82, 92 |
| Spring recording dynamometers | — | — | 60÷150 | 3, 46, 49, 50, 92 |
| Hydraulic dynamometers for brakes | — | — | 70÷800 | 3, 49, 50, 92 |
| Decimal scales for brakes | — | — | according to size | 22, 51 |
| Water brake of the Lavytt type | 50 | 66–67 | by special order | 22, 51 |
| ” ” Froude | 54 | 72–75 | 2÷4 per h.p. | 28, 38, 73 |
| ” ” Rato | 57 | 77–80 | by special order | 9 |
| ” ” Westinghouse | 60 | 82–84 | ” | 79 |
| ” ” Föttinger | 306 | 380–382 | ” | 68 |
| Indicators (dynamometers) of torsion: Föttinger | 66 | 88 | ” | 68 |
| Denny-Johnson | 69 | 98 | 850–1000 | 19 |
| ” with recording | 70 | — | 1100–2500 | 19 |
| Bevis-Gibson | 71 | 99–104 | — | 39 |
| Amsler-Laffon | 74 | 105 | by special order | 3 |
| ” from 10 to 1000 kg m | 75 | 106–107 | 300–1500 | 3 |
| Tomkinson-Smith | 76 | 108–112 | 370–530 | 57, 87 |
| Froude | 79 | 113–114 | by special order | 35a |
| Sayers | 80 | 115–118 | ” | 65 |
| Ramsay | 84 | 122–126 | ” | 40, 82 |
| Friedrich Lux | 85 | 127–129 | ” | — |
| electric Davyson | 89 | 136–134 | ” | 37 |
| ” Denny-Johnson | — | — | 800–900 | 19 |
| Bettger self-recording load indicator | 97 | 140 | 235–250 | 40, 82 |
| Laboratory mercury-in-glass thermometers | 98 | — | 1÷30 | 11, 30, 33, 56, 67, 72, 77, 83, 85 |
| ” ” ” factory | 99 | 142 | 3÷30 | 11, 30, 33, 40, 56, 67, 77, 82, 83, 85 |
| ” metal thermometers | — | — | 40–150 | 40, 62, 82, 55 |
| Instrument for calibrating thermometers at 0°C | 104 | 145 | 3÷15 | 30, 33, 67, 77, 83 |
| ” ” ” ” +100°C | 105 | 146 | 8÷15 | 30, 33, 67, 77, 83 |
| Thermocouple, iron, nickel; silver-constantan | 110 | — | 4÷25 | 8, 27, 36, 40, 50, 55, 56, 67, 70, 82, 83, 84, 85, 92 |
| Thermoelements for temperatures 0÷+500°C | 113 | 152 | 5÷15 | 36 |
| Bristol compensator | 114 | 154 | 3÷10 | 10 |
| Schwartz compensation device | 114 | 155 | by special estimate | 36 |
| Millivoltmeters for thermoelements | 115 | — | 50÷70 | 8, 10, 11, 32, 36, 40, 50, 54, 56, 67, 70, 82, 83, 85, 92 |
| ” ” ” | 115 | 156 | 86–90 | 29, 59, 85, 87 |
| ” ” ” | 115 | 157 | 90 | 29, 59, 85, 87 |
| ” ” ” | 116 | 158 | 80–90 | 27, 84 |
| ” ” ” | 117 | 159 | 100 | 8, 11, 29, 85 |
| Set of instruments for the zero method | 117 | 160 | 430 | 59, 87 |
| Self-recording millivoltmeters | 118 | 161 | 230–400 | 8, 27, 29, 56, 59, 67, 83, 84, 85, 87 |
| Switches for thermoelements | 119 | 162 | 2÷5 | 8, 29, 36, 59, 85, 87 |
| Resistance thermometer from +100 to +600°C | 124 | 169 | 20÷30 | 54, 59, 87 |
| ” ” up to +500°C | 124 | 170 | 5÷15 | 8 |
Appendix 2.
| Name of apparatus | Indicate: p. | Indicate: drawing | Cost, rubles | Firm Nos. from Table 17 |
|---|---|---|---|---|
| Resistance thermometer for water up to \(+150^\circ\) C. | 124 | 171 | 5–15 | 8 |
| ” ” from \(-100\) to \(+500^\circ\) C. | 125 | 172 | 25 | 27, 59, 84, 87 |
| Galvanometer for the apparatus according to drawing 172 | 125 | 173 | 125 | 27, 59, 84, 87 |
| Resistance thermometers of quartz glass | 126 | 176–178 | 18–25 | 29, 50, 85, 87 |
| Wheatstone bridge with accessories for the apparatus according to drawings 177–178 | 127 | 179 | 120–230 | 29, 85 |
| Resistance thermometer for a zero vessel up to \(+500^\circ\) C. | 127 | 180–182 | 20–40 | 11 |
| U-rod set for the apparatus according to drawings 180–182 | 127 | 183 | 200 | 11 |
| Schaeffer metal manometers | 134 | 185–186 | 8–25 | 17, 18, 40, 49, 50, 55, 62, 72, 82, 92 |
| ” ” Bourdon | 135 | 187 | 10–50 | 17, 18, 40, 49, 50, 55, 62, 72, 82, 92 |
| ” ” improved type | 136 | 189 | 10–50 | 17 |
| ” ” control | 137 | 190–192 | 25–45 | 17, 40, 50, 62, 82, 92 |
| Recording manometer | 138 | 193 | 45–95 | 49, 50, 62, 82, 92 |
| ” ” | 138 | 194–195 | 65–100 | 17, 49, 62, 82 |
| Water loops for connecting a manometer | 139 | 196–198 | 2–8 | 17, 18, 50, 55, 62, 72, 82, 92 |
| Walter apparatus for connecting a manometer | 139 | 199 | 9–12 | 18, 72, 82 |
| Devices for connecting a manometer | 140 | 200 | 1.5–7 | 17, 50, 55, 62, 92 |
| ” ” ” | 140 | 201 | 3–8 | 17, 50, 92 |
| ” ” ” | 140 | 202 | 3–4 | 18, 72, 82 |
| Connection of a manometer with a Föttig separator | 140 | 203–204 | 35 | 17 |
| Mercury manometer | 142 | 206 | 10–16 | 50, 55, 82, 92 |
| Differential mercury manometer | 143 | 207–208 | by special estimate | 50, 92 |
| Recording mercury manometer | 143 | 209–211 | ” | 26, 80 |
| Metallic vacuum gauges | 144 | — | 4–50 | 17, 49, 50, 55, 62, 82, 92 |
| Naumann barovacuum gauge | 146 | 212 | 70 | 82 |
| ” Frerichs | 146 | 213 | 75 | 82 |
| ” mercury | 148 | — | by special estimate | 42 |
| Mercury vacuum gauge | 147 | 214 | 10–15 | 17, 50, 82, 92 |
| ” manovacuum gauge | 147 | 215–216 | 55 | 17, 50, 82, 92 |
| ” recording vacuum gauge | 150 | — | by special estimate | 26, 80 |
| Shortened barometer (vacuum gauge) | 148 | 217 | ” | 33, 67, 77, 83 |
| ” ” “kinetometer” | 148 | 218 | ” | 7 |
| Apparatus for connecting a vacuum gauge | 150 | 219 | 3–8 | 17, 50, 82, 92 |
| Mercury manometer for selecting metallic pressure gauges | 151 | 220 | 35–60 | 17, 50, 82, 92 |
| Press for checking metallic manometers | 152 | 221 | 65–130 | 17, 50, 62, 82, 92 |
| Steam boiler for checking metallic manometers | 153 | 224–225 | 110 | 17 |
| Glycerin press ” ” ” | 154 | 226 | 80–100 | 17, 50, 82, 92 |
| Apparatus for checking metallic vacuum gauges | 155 | 227 | 80–175 | 17, 50, 82, 92 |
| Dreyer, Rosenkranz and Droop indicator | 156 | 227–231 | 120 | 17 |
| ” Mayhak | 158 | 232–234 | 135 | 40, 42 |
| ” Wagner | 159 | 235–236 | 150–220 | 17 |
| Mago apparatus with indicator | 160 | 237 | 180–200 | 16, 17 |
| ” ” for rapidly changing pressures | 161 | — | 210 | 16 |
| Mercury and aneroid barometers | 107 | — | 8–60 | 15, 30, 49 |
| Kraevich barometer | 107 | — | 60 | 91 |
| Hypsometer | 108 | — | 30–65 | 80 |
| Carpenter throttling calorimeter | 172 | 254 | 75 | 50, 82, 92 |
| ” ” Varus | 173 | 255 | 140 | 16 |
| ” ” without a water separator | 173 | 255 | 80 | 16 |
| Carpenter calorimeter-water separator | 175 | 257 | 125 | 50, 82, 92 |
| F. Beier plant steam meter | 179 | 260–262 | by special estimate | 20 |
| ” ” Renania | 180 | 263–217 | ” | 12, 76 |
| ” Gehre recording | 181 | 268–271 | 500–765 | 23, 82 |
| ” ” without recording | — | — | 90–440 | 23, 82 |
| ” Galske and Co. | 184 | — | by special estimate | 26, 80 |
| ” Eckardt | 184 | 272 | 450–780 | 18, 72 |
Selection of Instruments
| Name of instrument | Indicated: p. | Indicated: fig. | Cost, rubles | Firm nos. from Table 17 |
|---|---|---|---|---|
| Junker’s barometer | — | — | by special estimate | 34, 93 |
| Water meter with Woltmann vane | 188 | 276 | — | 59, 36, 87 |
| “Simmens and Halske” velocity meter | 189 | 277 | 3–2 rub./m³ h. | 59, 36, 87 |
| Dreyer, Rosenkranz and Droop velocity water meter | 190 | 278—280 | 3.3–0.3 rub./m³ h. | 17, 32, 86 |
| Venturi water meter | — | — | by special estimate | 1, 59, 75, 86, 87 |
| Ludwig Greve instrument | 191 | 281 | — | 25 |
| “Rota” meter | 192 | — | — | 14, 44 |
| Kennedy piston water meter | 192 | 282—283 | 0.07–0.02 rub./h.p. | 18, 72 |
| Schmidt piston water meter | 192 | 284—287 | 0.12–0.03 rub./h.p. | 35 |
| Frager piston water meter | — | — | 0.03–0.012 rub./h.p. | 86 |
| Disc water meters | 194 | 288 | 0.014—0.009 rub./h.p. | 59, 36, 87 |
| Reihling open water meter | 195 | 289 | by special estimate | 47 |
| Schild open water meter | 196 | — | 0.16–0.02 rub./h.p. | 52 |
| Torelli open water meter | 196 | 290 | 0.16–0.05 rub./h.p. | 66 |
| Ekwall open water meter | 197 | 291 | 0.16–0.02 rub./h.p. | 18, 72 |
| Etard open water meter with tilting tanks up to 2700 liters/h. | 198 | 292—293 | 0.16–0.03 rub./h.p. | 18, 72 |
| Leinert open water meter with tilting tanks | 198 | 294—295 | 0.8–0.4 rub./liter·h. | 78 |
| Steinmöller open water meter with tilting tanks | 199 | 296—301 | 0.8–0.2 rub./liter·h. | 63, 76 |
| Open water meter by Simmens Bros. for hot water | 201 | 302—303 | 0.4–0.12 liter (depending on size) | 59, 86, 87 |
| Scales—decimal, forty-pound, etc. | 203 | — | — | 22, 31 |
| Zunzher dynamo water meter | 212 | 317—318 | by special estimate | 64 |
| Areometer | 219 | — | 1–4 | 33, 56, 77, 83, 90 |
| Pycnometer | 219 | 319 | 3–5 | 15, 30, 33, 56, 67, 77, 83, 85 |
| Erlenmeyer flask | 221 | 320 | 2–4 | 33, 67, 72, 77, 83, 85, 90 |
| Burette for determining acid content in oil | 221 | 321 | 6–8 | 33, 67, 77, 83, 90 |
| Chemical scales, tripods, burners, and other apparatus for chemical and physical measurements | 219—222 | — | — | 11, 15, 33, 56, 67, 77, 83, 85, 90 |
| Simple apparatus for determining the flash point of oil | 222 | 322 | 10–20 | 33, 67, 77, 83, 90 |
| Marcusson apparatus for determining the flash temperature of oil | 223 | 323—324 | 30 | 33, 60, 67, 77, 83, 90 |
| Pensky-Martens apparatus for determining the flash temperature of oil | 224 | 325 | 60 | 33, 60, 67, 77, 83, 90 |
| Apparatus for testing oil in the cold | 225 | 326—327 | 10—15 | 33, 67, 77, 83, 90 |
| Engler viscosimeter | 226 | 328 | 45–62 | 33, 60, 67, 77, 83, 90 |
| Wilkens apparatus for testing oil | 227 | 329—330 | by special estimate | 1, 67, 75, 83, 90 |
| Dettmar apparatus for testing oil | 229 | 331—332 | 175—218 | 21, 33, 67, 77, 83 |
| Wagner derrauer | 254 | 343 | by special order | 17 |
| Micrometer | 262 | — | 2–20 | 11, 53, 95 |
| Instrument for measuring small gaps | 262 | — | 2–5 | 53, 95 |
| Seismograph with pendulums | 263 | 349 | 350–1000 | 15, 41, 61 |
| Vibrograph (the Simmens Bros. mercury instrument) | 264 | — | on request | 57, 87 |
| Diagram drum for Golitsyn’s instrument | 265 | — | 200–350 | 11, 15, 41, 46, 49, 61 |
| Grunmach apparatus (seismograph) | 266 | 351 | by order | 11, 46, 49, 61 |
| Detectorphone | 268 | 352 | 80 | 6, 24 |
| Wolz apparatus | 268 | 353 | 3–5 | 5 |
| Counting ruler, simple (25 cm) | 230 | — | 3–6 | 43, 71 |
| Counting ruler, accurate (50 cm) | 230 | — | 12–25 | 43, 71 |
| Counting ruler, “precision” (25 cm) | 230 | — | 7–9 | 43 |
Subject and Name Index.
Aachen Society for supervision of steam boilers 181.
Accumulator elements for resistance thermometers 124, 128.
Amsler-Laffon, torsion indicators 74—76.
“Anio-Maru,” torsion indicator 82.
Asphalt, content in lubricating oil 222.
Augsburg-Nuremberg Works, turbines 32, 283, 287.
Heat balance, turbines 295;—refrigerator 310.
Bandage fastening, effect on the work of steam 271;—testing of material 272.
Banks, experiments 271.
Baro-vacuummeters 146, 149.
Barometers 167;—Kraevich 167;—simplified (vacuummeter) 148—149.
Barus, calorimeter 173.
Bato 270.
Bach, verification of manometers 152.
Beyer & Co., steam meter 179.
Bendemann, water separator for steam meters 180.
Böttcher, load indicator 96—98.
Bifluod tachometer 9.
Bläs 270.
Bolte, stethoscope 268.
Barrel calorimeter 169.
Braun, resistance thermometers 124—125.
Brown-Boveri 30, 186, 233, 283, 284, 287, 289.
Brown-Curtis 281, 287.
Briling 270, 271.
Bristol, compensator for thermal elements 114.
Brady and Martin, draft gauge 148.
Bourdon, manometers 135, 161.
Bevis-Gibson, torsion indicators 71—74.
Büchner 270.
Wagner, indicator 159;—derivator 254.
Vacuum gauges 144—150:—metal 144—146;—mercury 147—150;—connection 150;—verification 155—156.
Wanzel and Son-Venant 236.
Watkinson 270.
Notching refrigerator, determination of steam consumption 217.
Introduction of thermometers 100—101.
Magnitude of turbine clearances, measurement 261.
Ventilation resistance 271.
Venturi, water meter 306.
Westinghouse, water brake 61—62.
Westinghouse-Parsons 283, 284, 287, 296.
Taking a steam sample 170—172, 304.
Villans and Robinson 272.
Wilkens, apparatus for testing oil 227.
Viscosimeter 226.
Switches 118—119.
V. K. E. (General Electricity Company) 31, 33, 228, 233, 235, 272, 273, 295.
Humidity of steam, measurement 168—177; 304; effect on consumption 283, 287.
Effect of pressure on a mercury thermometer 103—104.
Water, consumption in absorption of work 41;—measurement of temperature 132—133.
Water meters 187—202:—high-speed 188—192;—Venturi 306; Woltmann 188;—Siemens and Halske 189, 194;—Dreyer, Rosenkranz and Droop 190;—Greffe 191;—Rota 192;—Zulzer 212;—piston 192—194;—Kennedy 192;—Schmid 192;—Thomson (disk) 194;—open 195; with fixed tanks 195;—Reichling 195;—Schilde 196;—Thoren 196;—Eckardt 197, 198;—with tilting tanks 198—201;—Leinert 198;—Steinmüller 199;—Br. Siemens 201; verification—202.
Subject and Name Index
Water press for checking manometers 152.
Water load resistance 39.
Water brakes 47—62.
Air, work of friction 76; measurement of the amount falling into the refrigerator 238.
Woltmann, tachometer 188.
Rotation of a turbine, retarded, experiments 246; — by dynamo 251; — accelerated for determining the moment of inertia 256, 257.
Height, temperature—oil 222—225.
Vulcan 273, 300.
Choice of barometer 167; — water meter 195, 213; — torsion indicator 71, 82, 96; — calorimeter for steam humidity 177; — manometer 161—162; — method of measuring steam consumption 213, 218; — method of measuring condensate 216; — method of measuring cooling water 218; — lubricating oil 219, 220, 222, 225, 226, 231; — tachometer 16—17; — thermometer 128—129; — spring balance 106—107.
Gaxa (pressure gauge) 113—114; 150.
Galvaks and Co. 113, 150, 181.
Gardner, torsion indicator 84.
Gari-Kamings, torsion indicator 70.
Hartmann and Braun, tachometer 16; millivoltmeter 116; — recording millivoltmeter 118; — resistance thermometers 125.
“Heliopolis,” torsion indicator 96.
Genzeke 271, 272.
Gere, steam meter 181, 186.
Gernen 284, 285, 286.
Gerzog, resistance thermometers 126.
Hypsometer 168.
Glycerin press for checking manometers 154.
Golitsyn 265.
Hopkinson, modulus of elasticity 63.
Hopkinson-Spring, torsion indicator 76—78.
Horn, tachograph 25, 251; — manual tachometer 21.
Gramberg 177, 271, 272.
Graphical method of reducing steam consumption to normal conditions 286; — images of results 295—297.
Grebe, water meter 191.
Grunmakh, seismograph 266.
Fott’s load-limiter for manometers 140.
Dense oils in the cold 225.
Gutermuth 270, 273.
Pressure, effect on the mercury thermometer 103—104; — measurement 133—178; measurement — in turbines 161—166; — lubrication 232; — axial 260, 311; — initial steam, effect on consumption 283, 287; — in refrigerators, effect on steam consumption 284, 287.
Dahlene and Nadrovsky 272.
Data 203; 207—212; 307.
Motion of steam through nozzles 270; — by guide devices 271; — by working blades 271.
Delapert 270, 272.
Donny-Johnson, torsion indicators 82—84, 96.
Denny-Johnson, torsion indicators 69—70.
Wagner’s derivator 254.
Turbine parts, testing 272.
Detectorphone 268.
Gibson, calibration of torsion indicators 94—95.
Gibson-Bazvis, torsion indicators 71—74.
Johnson, torsion indicator 89—93.
Johnson-Denny, torsion indicator 82—84; 96.
Jenn and Brown 273.
Torsion dynamometers 62—96.
Dynamic moment of rotational resistance 247.
Disk water meters 194.
Differential curve $\frac{dn}{dt}$ 252.
Differential manometer 141, 235.
Diffusers in turbines, experiments 272.
Pressure diagram, examples 165—166; 7—8 Mallia 216, 292, 295; — heat 7—8 244, 295; — Sankey 295.
Diagrams, measurement of steam consumption 178, 305—306.
Dobbie and Mac-Innes, indicator 160.
Dreyer, Rosenkranz and Droop, manometer with membrane 135; — spring-type
Appendix 3.
manometer 136;—control manometer 137;—boiler for checking manometers 153;—indicator 156;—diagram form 165; water meter 190.
Throttle calorimeters 172—175, 304.
Throttle calorimeters 172—175.
Actual work, determination 34;—measurement by brake 44, 48;—measurement by torque 63.
Ducomet manometer 134.
Iron-constantan thermocouple 106.
Fat, content in oil 222.
Test logs, forms 274—279, 297.
Factory laboratory 273.
Clearances in turbines, measurement 261, 262.
Retarded rotation, experiments 245.
Pressure recording in turbines 165.
Shut-off steam valve, leakage 235.
Zendtner, steam intake 171;—throttle calorimeter 174.
Mirror ruler 252.
Zinger 288.
Ash in oil 221.
Sulzer, tachometer 10;—tachogram from turbine 33;—water meter 212;—clearances in turbines 262;—experiments with turbine 273;—turbine test log 297.
Measurement of pressures 133—168;—in turbines, 161—166.
— values of clearances in turbines 261, 262.
— steam consumption 177—187, 235, 305—306, 307, 310.
— temperature 98—133;—in turbines, 128—133;—steam 128—132;—accuracy 129;—effect of projection (local overheating) 129.
— shocks 263—268;—transmitted by air 269.
— electrical energy 35—37.
Insulation of thermocouple wires 111.
Investigations of turbines, scientific and technical 269—273.
Indicator work, 34, 35.
Indicators 156;—Wagner 159;—Dreyer, Rosenkranz and Droop 156;—Dobbie, McInnes 160.
Torsion indicators 62—96;—mechanical 64—70;—Gary-Cummings 70;—Denny-Edgecombe 69—70;—Kolley 64—65;—self-recording 66—69;—Föttinger 65—69, 303;—optical 71—82;—Amsler-Laffon 74—76;—Bevis-Gibson 71—74, 96;—Hopkinson-Spring 76—78, 96;—electrical 82—93;—Gardner 84;—Denny-Johnson 82—84, 96;—Johnson 89—93;—Lux 86—89;—Rambal 84—86;—calibration and checking 93—96.
Inertia, moment—finding 255.
“Inflexible,” torsion indicator 96.
Repairing entries 280.
Testing of turbine materials and parts, 272.
— turbines, 272—273;—beginning 273;—duration 274.
Sources of errors when using resistance thermometers 122—124.
Josse 132, 204, 238, 271, 272, 284.
“Kair,” torsion indicator 96.
Calibration of torsion indicators 93—95.
Calender, resistance of platinum 119;—compensation loop 123.
Calorimeters 169—177;—Barrus 173;—boiler 169;—water separator 175—177;—Zendtner 174;—Carpenter 175;—Stott and Pigott 304;—refrigerator 169;—corrections for throttling and other 174, 176 and 305; comparison 177.
Kammerer, measurement of turbine condenser 205.
“Carmania” — apparatus for measuring pressure 163.
Carpenter, calorimeter 175.
Rolling, determination of moment of inertia 255.
Kegler, water meter 192.
Keiser and Schmidt, thermocouple 112—113;—Schwarz compensator 114—115;—millivoltmeter 115.
Kemble 270.
Cummings-Gary, torsion indicator 70.
Subject and Name Index
Kennedy, water meter 192.
Curtis, turbine 262, 273, 283, 284, 291.
Kinotometer 148.
Acids, content of mineral acids in oil 220;—organic acids in oil 220, 221, 222.
Kolly, torsion indicator 64—65.
Bristol compensator 114.
Calendar compensating loop 123.
Schwartz compensating device 114—115.
Compensating connection of thermoelements 107—108.
Condenser, measurement 201, 204, 205, 216, 307—309.
Constantan 13, 38, 43, 106.
Construction of thermoelements 110;—resistance thermometers 124—132.
Control manometers 136—137.
Steam boilers for checking manometers 152—154:—Bach 152—153;—Dreyer, Rosenkranz and Droop 153—154.
Coefficient of water outflow 207;—steam through nozzle of diaphragm 306.
— friction of wood on cast iron 45;—oil 227—232.
Kraevich, barometer 167.
Crane for connecting several manometers 162.
Curve n rev./min. 251.
— dn (acceleration) 252.
— dt (acceleration) 252.
Inspection record 280.
Torsion, angle, modulus 62;—indicators 62—96.
Cambridge Scientific Instrument Co., millivoltmeter 117;—resistance thermometers 127—128.
Capsule, method 120;—instrument 121.
Labyrinths, steam leakage 235, 237, 272.
Laboratory, works 273;—of the Charlottenburg Polytechnic 235, 243.
Laval, turbine 14, 29, 30, 43, 45, 46, 268, 271, 272, 284, 287, 291.
Incandescent lamp, load resistance of—37.
Lasche 272.
Levitsky 270, 271, 272.
Lesel 284, 285.
Leinert, water meter 198.
Band brake 45—47.
Livshits, brake (printed by mistake as Olden) 51.
Mirror scale 252.
— counting scale 280.
Turbine blades, steam motion 271;—influence of pitch 271.
Loschge 271, 273.
“Lusitania,” torsion indicator 96.
Radiation, heat loss 242;—corrections in calorimeters 174, 176, 305.
Lucks, torsion indicator 86—89.
Magneto-electric tachometers 42.
Manganin 13, 38, 43.
Mano-vacuum gauge 144—146.
Metal manometers 133—141;—control 136—137;—self-recording 138, 143;—connections 139—141;—mercury 141—144;—differential 143;—verification 150—153.
Marguerre 271, 273, 294.
Markson, instrument for determining the flash temperature of oil 223.
Marten-Pensky, instrument for determining the flash temperature of oil 224.
Oil (lubricant), principal requirements 218;—specific gravity 219;—acid content 220;—resinous impurities 221;—ash content 221;—flash temperature 222;—solidification in the cold 225;—viscosity 226, 229;—coefficient of friction 227—232.
Materials for turbines, testing 272.
Mato, instrument 160, 161.
Melms and Pfenninger, turbine 272, 292, 297.
Metal vacuum gauges 144—146.
— manometers 133—141.
— load resistances 38.
Mechanical torsion indicators 64—70.
— recoil 231, 250.
— losses, measurement 245.
Millivoltmeters 115—118;—Hartmann and Braun 116;—Keiser and Schmidt 115;—Cambridge Scientific Instrument Co. 117;—self-recording 117—118;—Siemens and Halske 115—116.
Appendix 3.
Mineral acids, content in oil 220.
Modulus of torsional elasticity of steel shafts 63.
Moyer 283, 284.
Mollier 215, 216, 292, 295.
Moment of inertia, determination 255; — method of swing 255; — method of accelerated rotation 256.
— of mechanical resistances 246—251; — run-up 247; — direct rotation 247; — brush friction 247.
— of idle friction of the turbine 259.
— of turbine friction 260.
Wheatstone bridge for resistance thermometers 127.
Thermocouple constant, thermocouple 106.
Set, for thermoelement by the zero method 117.
— Unipivot for resistance thermometers 127.
Load, influence on steam consumption 288; — accounting for the influence 291.
— Betz’s indicator 96—98.
— mercury manometer 154.
Load resistances 37—43.
Nadrowski and Dahlke 272.
Directing device, motion of steam 271.
Naumann, barovacuum meter 146.
Scientific-technical turbine tests 269—273.
Finding corrections to steam consumption $D$ 287.
Finding mean values 279; — accuracy 280.
Initial steam pressure, influence on steam consumption 283, 287.
Negretti and Zambra, barovacuum meter 149.
Impermeability of a steam boiler; measurement 309.
— of the surface condenser 217.
Normal conditions of steam operation 287.
Zero method, measurement by thermoelements 107—108; — by resistance thermometers 121.
Zero of the scale of torsion indicators 95—96.
Processing of experimental material 279.
Samples of pressure diagrams 165—166.
— journal of turbine tests 298—299,
— tachograms of turbines 29—33.
Use of tachometers 18.
— of thermometers 100—102.
Volumetric methods of water measurement 204.
Olden, brake 300.
Omund, tachometer 8.
Thermoelement surveys 111—113.
Optical indicators 71—82.
Experiments with rotation, slowed 246; — accelerated, 256.
Organic acids, content in oil 220, 221, 222.
Axial pressure 260; — measurement 261; — from the comb screw, measurement 311; — steam leakage through unloading pistons 238, 239.
Oscillogram 33.
Poncelet openings 207, 218, 274, 277, 309.
Recoil, calculation 292.
Open water gauges 195.
Open crucible, method of determining the flash temperature of oil 222.
Relative loss for after-admission 274.
Reports in turbine testing 273; — beginning 273; — intervals between 274.
Cooling water, influence of temperature on steam consumption 283; — consumption during braking 11, 46, 49.
Errors when using resistance thermometers 122—124.
— series of measurements 280.
Steam boilers for checking manometers 152—154.
Steam meters 177—187, 235; — Beyer and Co. 179; — Hallwachs 184; — Gehre 181, 186; — Rehmann 180; — Eckardt 184; — connection 186.
Parsons turbine, tachograms 30; — pressure measurements in stages 163; — steam pressure diagrams 165, 166, 186; — leakages through labyrinths 234, 239, 241; — loss for after-admission 243—245; — measurement of mechanical losses 247, 249; — measurement of axial pressure 260; — tests 271, 272, 273; — influence of operating conditions 283, 284, 287, 291, 296.
Subject and Name Index
Steam, motion through nozzles 270;—motion through guide apparatus 271;—motion through working blades 271;—shut-off, measurement of leakage 235;—flow rate 33, 282, 291;—measurement of flow rate 177, 187, 235.
— taking a sample for the calorimeter 170—172, 304.
— measurement of temperature 130—132;—measurement of humidity 169—177, 304—305.
Pensky-Martens, apparatus 221.
Steam superheating, influence on steam consumption 283, 287.
Switches 119.
Displacement of the path of a mercury thermometer 104.
Pneumometer 219.
Feed water, steam consumption by consumption 213.
Surface condenser, tightness 217.
Checking vacuum gauges, 155;—indicators, torsion 95—96;—manometers, piston 151;—manometers, load 154;—thermometers, mercury 101—105;—thermoelements 105, 109;—resistance thermometers 105, 124;—water meters 202;—tachograph of Horn 28.
Absorption of electrical energy 37—43.
Load indicator of Böttcher 96—98.
— (its indication) established from stop 273.
Useful work 34, 44.
Full output \(c_0\) of the turbine 292.
Indications, influence of temperature—on the indication of a thermoelement 110.
Gonses, holes 207, 218, 274, 277, 309.
Corrections to mercury thermometers 102—104;—for resistance of thermoelements 108—109;—for radiation in calorimeters 174, 176, 305;—from instruments 282.
Piston water meters 192.
Series connection of thermoelements 113.
Thermal aftereffect 104.
Pensky-Martens 224;
— Ritoff, for indicating the water level 264;—Engler;—for measuring clogging in boilers 309;
Mechanical losses, measurement 245;—steam, measurement 234—242;—of a steam turbine at idling 242.
Prandtl 270.
Press for checking manometers 152;—glycerin 154.
Instruments, Bolte 268;—Velkens 227;—Golitsyn 265;—Grunmach 266;—“detector” 268;—Dettmar 229;—Markuson 224;—Mato 160, 161; Pensky-Martens 224;—Richard, for indicating the water level in a boiler 309;—Siemens, for measuring vibrations 264;—Engler 226;—for measuring clogging in tubes 262—263;—for determining cast-iron oil on the run 225;—guiding in turbines, steam motion 271;—for measuring axial pressure on the shaft 260, 310—311.
Bringing steam consumption 283—287.
— tachometer, in action 18.
Impurities of lubricating oil 221.
Accessories of thermoelements 110—119.
Connection of hand tachometers 22.
— manometers 139—141, 161;—vacuum gauges 155.
Devices for switching on the brush of revolutions 3—4.
Samples, taking—of steam 170—172, 304.
Wires of thermoelements 110—111; insulation 111.
Checking, see verification.
Duration of turbine test 274.
Intervals between readings during turbine test 274.
Spring (metal) manometers 133—141.
The simplest cheap method of determining the temperature of an oil bath 222.
Work, actual (effective) 34, 44, 48, 63;—indicator 34;—useful 34, 44, 48;—friction against steam 248, 250, 271;—friction against air 76.
Working steam, consumption 213, 215.
Working blades, steam motion 271.
Radial turbine of Eiermann 132, 238.
Unloading pistons, steam leakage 238, 239, 241, 242.
Appendix 3.
Dimensions of electrodes of water resistances 40.
Rupture of the mercury column in a thermometer 101—102.
Distance between blades, effect on the operation of steam in a turbine 271.
Rambal, torsion indicator 84—86.
Water consumption when lowering the load 41;
— turbine lubrication 233;
— steam per unit of power 35, 282, 291;
— steam, measurement 177, 213, 218, 306—307, 310; — working 213, 215; — determination 283—287; — effect of initial pressure 283; — effect of superheating 283; — effect of humidity 284; — effect of pressure in the refrigerator 284; — corrections 286—287.
Rato, brake 56—60; — turbine 164, 270, 271, 287, 291.
Resonance tachometer 13.
Test results, summary 297.
Test results, summary 227.
Reichling, water meter 195.
Renania, water meter 180.
Retcher 272.
Ridder-Stumpf, turbine 272.
Ripe 272.
Richards, Westgarth and Co., plant 273.
Richard, instrument 309.
Robinson, Willans, 272.
Rosenhain 270, 271.
“Rota” water meter 192.
Mercury vacuum gauges 147—150; — switches 119; — manometers 141—144, 235, 306; — thermometers 98—105.
Hand revolution counters 1—4; — tachometers 12; — tachograph 24.
Sajahiro, torsion indicator 80—82.
Salnykin—labyrinths, experiments 272.
Sankey, diagrams 295—297.
Self-recording torsion indicators 66—69, 88; — metallic manometers 138—139; — mercury manometers 143—144; — mercury vacuum gauges 150; — tachometers 24.
Certificate of the F.-T. I. I. 104, 108, 110.
Summary of results 297.
Seismographs 263, 265, 266.
Seng-Venant and Wantzel 236.
Silver-constantan (thermocouple) 106.
Compressed carbon dioxide for checking manometers 152.
Sibley 270.
Siemens and Co., br., 201, 264.
Siemens and Halske—oscillograph 33;
— millivoltmeters 115—116; —
instruments for the zero method 117; —
water meters 189, 194.
Steam velocity, effect on measurement of temperature 130—132.
Speed water meters 188—192.
Comparison, verification of manometers 151;
— verification of thermometers 104.
Lubrication of turbines 218—234; — investigation of basic properties 218—227; — acid content 220, 221, 222; — alkali content 220; — ash content 221; — sulfuric acid 220; — resinous impurities 221; — asphalt, tar 222; — comparison of grades of oil 231; — observation 232; — permissible temperature 233; — consumption 233.
Content in oils of acids 220, 221, 222; — alkalis 220; — ash 221; — resinous impurities 221; — asphalt, tar 222.
Nozzles, steam movement 270.
Resistances, load 35—43; — made of incandescent lamps 35; — metallic 38; — water 39—43.
— ventilation 271.
— effect on thermoelement 108—109.
— thermometers 119—128.
Shaking, measurement 263—268.
Junctions, cold, of thermoelements 109—110.
Methods of measurement, by thermoelements 107—108; — by resistance thermometers 120—122;
— determination of moment of inertia by rocking 255; — by accelerated rotation 256.
Comparison of oil grades 231; — steam consumption of different turbines 288; — instruments of different types, see “Choice.”
Mean values, finding 279.
Mean error 280.
Spring-Hopkinson, torsion indicator 76—78.
Stethoscopes 268, 269.
Stodola 76, 184, 212, 237, 250, 262, 270, 271, 272, 273, 283, 284, 285, 287, 292, 295, 297.
Mercury column, protruding 102—103;
— rupture 101—102.
Stott and Piggott 301, 305.
Subject and Name Index
Counting rule 280.
Revolution counter 1—5;—in connection with a tachometer 5.
— work of F. Lux 88—89.
Sulfuric acid in oil 220.
Mollier steam tables 215.
Turbine tachograms 29—33, 296, 300.
Tachographs 23—29;—Horn 25—29, 251;—manual 24.
Tachometer 5—23;—with loads 6;—with liquid 9;—magneto-electric 13;—resonance 13;—manual 19, 22;—with recording 24;—electric 13;—Hartmann and Braun 16;—Oemund 8.
Tachoscope 2.
Temperature, measurement 98—133;—room temperature, influence on thermoelement readings 110;—oil flash point 222—225;—lubricant 233;—cooling water;—influence on steam consumption 285, 287;—superheating, influence on steam consumption 283, 287;—measurement at turbines 128—133.
Heat lost by steam admission, 242;—loss diagram 244.
Thermal (entropy) diagram \(T—S\) 244, 295;—diagram \(I—S\) 216, 295.
— oil balance of a turbine 295; refrigerator 310.
Heat capacity of oil 234.
Thermal aftereffect 104.
Thermodynamic efficiency 292.
Thermometers, mercury 98—105;—factory 99;—handling 100—102;—checking 104—105;
— resistance 119—128;—methods of measurement 120—122;—sources of errors and their elimination 122—124;—Braun 124—125;—Hartmann and Braun 125;—Heraeus 126—128;—Cambridge Co. of Scientific Instruments 127—128;—Callendar 120, 124.
Thermocouples, selection 106—107.
Thermoelements 106—119;—influence of room temperature 110;—construction and accessories 110—119;—corrections for resistance 108—109;—application 270;—methods of measurement 107—108;—cold junction 109—110.
Tozi, turbine 260.
Ticks in steam pipe lines, influence on steam measurement 186.
Tomson, water meter 194.
Toren, water meter 196.
Brakes for turbines 43—62, 300;—water 47—63, 301—303;—Westinghouse 60—62;—Lewitt (mistakenly called Olden) 51; Olden 300—301;—Rato 56—60;—Föttinger 301—303;—Froude 54—56;—destroyers “Fursh” and “Fo” 58—60;—Stumpf 47—51;—Eiermann 52—54;—with blocks 43;—belt 46—47.
Accuracy and its calculation 280.
Friction, of air, work 76;—of wood on cast iron 45;—of disks and blades on steam, cast iron 45;—of disks and blades on steam 248, 250;—of oil 227—232; moment, —of a turbine wheel, measurement 259;—of dynamo-machine brushes 247.
Watkinson 270.
Compressed carbon dioxide for checking manometers, 152.
Specific gravity, of water at different temperatures 211;—of oil 219.
Whipple, set for resistance thermometer 127—128.
Wheatstone bridge for resistance thermometer 127.
Shortened barometer 148—149.
Improvement of turbine operation, experiments 272.
Labyrinth packing, steam consumption 237.
Accelerated rotation, determination of moment of inertia 256, 257.
Steady state of a turbine 242, 243, 273, 274;—indicator 273;—non-observance 293.
Leakage of water into the surface condenser 217;—of water from the steam boiler 309;—of shut-off steam through labyrinths 235, 272;—of steam through unloading pistons of a radial turbine 238;—of steam through unloading pistons of an axial turbine 239—242.
Factory thermometers 99.
Ferraris 13.
Föttinger, bladelets of revolution 65—69, 311;—calibration of indicators [[unclear: continues on next page]]
Appendix 3
torsion 93—94;—water brake 301.
Physico-Technical Imperial Institute (Ph.-T. I.) 104, 108, 109, 110.
“Florida,” torsion indicator 70.
Fogt, mud trap 140.
Fram, tachometer 13;—torsion indicators 79—80.
Freriks, barovacuum gauge 146.
Froude, water brake 51—56.
“Furuh” and “Fo,” brake 58—60.
Chemical method, determination of steam wetness 170;—determination of leakage into surface condensers, 217.
Refrigerator, vortex, determination of steam consumption 217, 310;—surface, determination of steam consumption 216;—surface, determination of leakage into 217;—pressure in, effect on steam consumption 281, 287;—calorimeter 169.
Cold junction of thermoelements, 109—110; 113—115.
Christlein 271.
Huguenin 271.
Celli—Mercury tachogram 32;—effect of operating conditions on steam consumption 284, 285, 287;—steam consumption 289, 291.
Number of decimal places in calculations, 279.
Schwarz, compensating device 114—115.
Schwetz 45.
Sheffer 134, 161.
Sheffer and Budenberg, instruments 134, 135, 140, 143.
Schilde, water meter 196.
Schinz, 135.
Scale of a torsion indicator, selection 95—96.
Schmidt, water meter 192.
Stumpf, brake 47—51.
Fitting for thermometers 100, 112.
Schultz, resistance thermometers 124.
Slot, contents in oil 220.
Series dynamo, friction moment 217.
Yasinsky 271, 305.
Edgcumbe-Denny, torsion indicators 69—70.
Eiermann, brake 52—54;—measurement turbine 132, 238, 261, 271, 295.
Eckardt, water meter 192, 197, 198;—barometer 184;—fitting for a manometer 140.
Electrical torsion indicators 82—93;—tachometers 13;—on energy, measurement and absorption 35—43.
Electrodes of water resistance 40.
Electromagnetic tachometer 22.
Engler, viscosimeter 226.
Entropy diagrams 216, 244, 295.
Erlicon, turbine 285, 287.
Effective work 31, 41, 48; see actual work.
-
Brown, Boveri & C-ie, Die Dampfturbinen, 4. Ausg. 1906, S. 57. ↩↩
-
Moyer, Steam turbines. New-York, 1908, p. 128; Moyer, Power plant testing, p. 298. ↩
-
Moyer, according to American usage, calls it 125-kW, but loads it in the test up to 207 kW. ↩
-
Moyer, Steam turb., p. 133; Moyer, Power plant test., p. 302. ↩
-
Z. Turb., 1911, S. 159. ↩
-
Stodola, Dampfturb., S. 212. ↩
-
Z. V. d. I. 1908, S. 516. ↩
-
Z. V. d. I. 1908, S. 1346. ↩
-
Z. Turb. 1909, S. 157. ↩
-
Bauer u. Lasche. Schiffsturb. S. 354. ↩
-
Bauer u. Lasche. Schiffsturb. S. 392. ↩
-
Bulletin of the Polytechnic Society, 1913, pp. 402–403; see also Lomshakov, Testing of Steam Boilers. 2nd ed. St. Petersburg, 1913, pp. 505–512. ↩
-
Bauer u. Lasche. Schiffsturb., S. 379. ↩
-
Proceed. Am. Inst. El. Eng. 1910, p. 1891. ↩