TESTS OF DRAINAGE PUMPING PLANTS. 
27 
brate the meter, but trie results obtained varied about 25 per cent, 
showing that the water quantities measured are unreliable. Indica- 
tor cards were taken on the high-pressure cylinder with an outside- 
spring Tabor indicator. The thermometer on this cylinder showed 
an average of 74.5° F. of superheat. The indicator used on the low- 
pressure cylinder was an inside-spring Thompson. The thermometer 
on this cylinder indicated an average of 49.2° F. of superheat. A 
counter attached to the valve gear of the engine, read usually at 
intervals of 10 minutes, gave the revolutions. The quantity of water 
pumped was measured by two Pitot tubes inserted in the suction 
pipes, traverses of the pipes being made at half-hour intervals. 
Headings of the gages in the suction and discharge canals were taken 
at half -hour intervals. Table 18 shows the results obtained during 
the test, and figure 2 is a graph showing the efficiency of the plant 
at various lifts. 
With the exception of the feed-water measurements the test was 
satisfactory. The only irregularity was due to the presence of air 
in the pump. As there was nothing to act as a flywheel except the 
impeller of the pump, there was a tendency for the engine to change 
speed rapidly on account of pockets of air in the water. This caused 
considerable variation in the indicator card from the high-pressure 
cylinder. Because of this variation six cycles were taken for each 
card, and in this, way a very close mean was obtained. 
Table 18. — Test of 72-inch unit of pumping plant No. 3, Axoca drainage district. Sejpt. 
13-14, 1916. 
Efficiency. 
Boiler, 
pressure. 
Speed. 
Indicated 
horse- 
power. 
Actual, 
lift. 
Discharge. 
Useful 
water 
horse- 
power. 
Time. 
Pump, 
engine, 
and 
Pump. 
piping. 
Lbs. per 
sq. in. 
R. p. m. 
Feet. 
Sec.-ft. 
G. p. TO. 
Per cent. 
Per cent. 
10.30 
146 
105.9 
188. 83 
2.22 
278. 35 
125, 000 
70.05 
37.08 
41.1 
11.00 
152 
106.1 
190.68 
2.19 
276.85 
124, 100 
68.70 
36.02 
40.4 
11.30 
151 
106. 
191. 65 
2.36 
278.08 
124,900 
74.40 
38.80 
43.2 
12.00 
153 
105.9 
187. 15 
2.46 
275. 25 
123, 500 
76.45 
40.84 
45.3 
12.30 
148 
105.9 
194. 28 
2.60 
273. 20 
122, 600 
80.40 
41.38 
45.9 
1.00 
149 
105.9 
197. 48 
2.73 
272.05 
122, 100 
84.20 
42.63 
47.3 
1.30 
149 
105.3 
196. 75 
2.86 
272. 85 
122, 300 
88.40 
44.92 
49.9 
2.00 
141 
105.9 
200.70 
2.98 
272.95 
122, 500 
92.20 
45.83 
51.1 
2.30 
151 
152 
106.1 
105.4 
202.45 
208. 15 
3.00 
3.48 
269. 40 
121,000 
106.20 
51. 03 
56.6 
3.30 
138 
105.8 
202.40 
3.59 
267. 65 
120, 100 
108. 80 
52. 43 
58.2 
4.00 
156 
105.8 
214.90 
3.68 
266. 05 
119, 400 
110.90 
51. 61 
57.3 
4.30 
145 
105.9 
214. 85 
3.96 
264.80 
118,800 
118. 80 
55. 37 
61.4 
5.00 
151 
105.6 
216. 75 
4.16 
265. 00 
118, 900 
124.90 
57. 65 
64.0 
5.30. 
148 
105.4 
216. 85 
4.23 
262. 65 
117,750 
125. 80 
58.06 
64.5 
6.00 
134 
105.2 
218.15 
4.26 
259. 60 
116,500 
125. 30 
57.20 
64.0 
9.00....... 
95 
103. 9 
245. 00 
7.03 
228.00 
102, 300 
181. 60 
74.18 
82.3 
9.20 
104.7 
256. 03 
7.23 
217. 25 
97,700 
178.00 
69.78 
77.4 
9.30 
142 
140 
105.2 
105.4 
266. 18 
277.40 
74.4 
10.00 
7.98 
194. 60 
87,300 
175.90 
63.40 
70.3 
