TESTS OF DRAINAGE PUMPING PLANTS. 
17 
Table 9. — First test of pumping plant in subdistrict No. 1, Lafourche drainage district 
No. 6, Nov. 23, 1912. 
UNIT NO. 1. 
Boiler 
pressure. 
Speed. 
Indi- 
cated 
horse- 
power. 
Actual 
lift. 
Water 
horse- 
power. 
Efficiency. 
Time. 
Discharge. 
Pump, 
engine, 
and 
piping. 
Pump 
and 
pipings 
11.45 
12.15 
12.45 
1.15 
1.45 
2.15 
2.45 
3.15 
3.45 
Lbs. per. 
sq. in. 
85 
92 
92 
87 
86 
94 
81 
92 
90 
R. p. to. 
164 
168 
172 
174 
173 
184 
170 
162 
179 
40.6 
46.4 
46.7 
48.0 
49.1 
55.5 
44.3 
37.6 
53.0 
Feet. 
2.60 
2.65 
2.72 
2.84 
2.95 
3.07 
3.17 
3.29 
3.42 
Sec.-ft. 
36.5 
40.5 
38.7 
40.7 
39.1 
41.1 
37.5 
34.5 
40.0 
G. p. TO. 
16,380 
18, 180 
17, 370 
18,260 
17, 550 
18,450 
16,830 
15, 490 
17,950 
10.75 
12.15 
11.92 
13.10 
13.06 
14.30 
13.45 
12.85 
15.50 
Per cent. 
26.5 
26.2 
25.6 
27.3 
26.6 
25.8 
30.4 
34.2 
29.3 
Per cent. 
29.5 
29.1 
. 28.4 
30.3 
29.5 
28.6 
33.8 
38.0 
32.5 
UNIT NO. 2. 
11.45. 
12.15. 
12.45. 
1.15. 
1.45. 
2.15. 
2.45. 
3.15. 
3.45. 
85 
146 
29.0 
2.60 
30.9 
13,870 
9.12 
31.3 
92 
149 
30.3 
2.65 
32.3 
14,500 
9.70 
32.1 
92 
150 
30.5 
2.72 
31.8 
14, 270 
9.80 
32.1 
87 
172 
44.4 
2.84 
35.0 
15,710 
11.25 
25.3 
86 
171 
44.6 
2.95 
35.6 
15,980 
11.90 
26.7 
94 
175 
48.0 
3.07 
36.2 
16, 250 
12.60 
25.0 
81 
165 
41.0 
3.17 
34.6 
15,530 
12.40 
30.3 
92 
156 
34.4 
3.29 
31.7 
14,230 
11.80 
34.4 
90 
172 
45.9 
3.42 
34.9 
15, 670 
13.50 
29.5 
34.7 
35.7 
35.7 
28.1 
29.7 
27.8 
33.7 
38.2 
32.8 
i Engine assumed to be 90 per cent efficient. 
It will be noted that the lift was less than 3 feet, which is much 
too low for efficient operation of the pumps. The capacity of the 
pumps was large and they were undoubtedly run too fast to get the 
best efficiency. By examining Table 9 it will be seen that when the 
discharge dropped to 30 cubic feet per second the efficiency of pump 
and piping was about 38 per cent. 
SECOND TEST. 
At the time of the first test the static lift of the pumps was low, 
between 2.6 and 3.4 feet, and the pumps were operated at about 30 
per cent over their rated capacities. While this information was 
valuable in showing overload capacity and the efficiency of the pumps 
at low lift, it w r as desired to know what efficiency this type of pump 
would give when operated at the rated capacity and at a static lift 
of at least 4 feet. The second test made for this purpose included 
only the engine and pump of unit No. 1. The first reading was taken 
while the pump was working at a 50 per cent overload and shows the 
reduction in efficiency that may be expected to result from such an 
overload. In computing the average efficiency for the test this first 
reading is omitted. Table 10 gives the results of the test. 
39782— 22— Bull. 1067 3 
