Engine tests; embracing the results of over one hundred feed-water tests and other investigations on various kinds of steam engines, conducted by the author by Barrus George Hale

Author:Barrus, George Hale
Language: eng
Format: epub, pdf
Tags: Steam-engines -- Testing
Publisher: New York, D. Van Nostrand company
Published: 1900-03-25T05:00:00+00:00

ENGINE No. 38

120^

100-

80-

60-

40-

20-

0-

H.P. Head End

H.P. Crank End

-120 -100 - 80 — 60 —40 —20 0

L.P. Head End

10

- 5

- 0

- 5

- 10

10

5 -0-

6 -10 —

L.P. Crank End

ENGINE No. 39.

Compound Condensing Engine.

Data and Results of Feed-Water Test.

Character of steam

Duration

Weight of feed-water consumed 11

Feed-water consumed per hour 3

Pressure in steam pipe above atmosphere

Vacuum in condenser

Revolutions per minute

Mean effective pressure H. P. cylinder

Mean effective pressure L. P. cylinder

Indicated horse-power H. P. cylinder

Indicated horse-power L. P. cylinder

Indicated horse-power, whole engine

Feed-water consumed per I. H. P. per hour

Measurements based on Sample Diagrams.

Engine No. 39 is a single valve, cross compound, unjacketed engine, with a shaft governor operating 011 the cut-off of the high-pressure cylinder. The valves are of the piston type provided with an inefficient ring packing. A jet condenser is used, operated by an independent air-pump driven with steam taken from the engine pipe. The quantity thus used was determined by an independent test and allowed for. Steam is supplied from vertical water-tube boilers, and a separator placed in the steam pipe secured what was believed to be commercially dry steam without superheating. The valves and pistons all leaked a considerable amount. The load consisted of dynamos furnishing current for electric lighting. With the exception of the low-pressure cylinder and the valves, this engine is the same as No. 35. During the interval between the tests the engine had been provided with new valves fitted with packing and a complete new low-pressure cylinder of larger size.

Referring to the test on Engine No. 35, the figures given here show an improvement, due largely to a better distribution of the steam, which was accomplished by a change of proportion in the steam cylinders. The increase in the size of the low-pressure cylinder enabled this cylinder to do a larger proportion of the work, with corresponding advantage. The reduction in the quantity of feed water consumed per horse power per hour amounted to 18.3% ; and the reduction in the steam accounted for by the diagrams at cut-off, which is 17.5%, furnishes a reason for the change. In view of the leakage of the valves and pistons, it is not surprising that the proportion of steam accounted for is low ; and this is true in the case of both engines.

To make a ready comparison of the diagrams in the two cases under consideration, showing the general effect of the change of cylinders, diagrams t'rom Engine No. 35, taken with the same load, are superposed in dotted lines upon those relating to No. 39, which are represented in full lines.

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