44 
BI'LLETIX 1067, U. S. DEPARTMENT OF AGRICULTURE. 
Table 37. — Tt sts q f : i - T ':>ot Wood screw drainage pump at New Orleans pumpina station 
No. 1. Nov. 17. 1917. 
TE-T OF NOV. 17. 191C. 
Quantity pumped. 
r M i- Crrrpr- Corr ec- 
Na Speed. - |™ Leak- £**£ tionfor Cor- 
ured Brad a - e 5o?a-e STora ? e 
in S^J through ^^e in ^^ 
flume " Canal. *■*»■ ci. g^f Tit ^ 
Lift. 
Water 
horse- 
now er. 
Ifca* 
ured 
elec- 
tri :.". 
horse- 
power. 
Meas- 
ured 
E.H.P. 
X0.94= 
B.P. 
innut 
pump. 
. jet: . .:-' Uet . 'Sec. ft. 5 
o. 
74.1 
74.1 
74 
475. 73 
481.54 
471. 70 
1.74 
1.74 
1.74 
1.74 
.2 
3.74 
21.18 
11. 45 
-0.90 
-4. 70 
-4. 34 
-3. 31 
182. 92 
187. 
i . -■ 
4S7. 11 
Feet. 
r.4S 
7.415 
416.0 
414.5 
412. 5 
413. 9 
551.0 
58 " 
552 
582. 52 
547. 5 
585. 03 
eieney 
P. C>. 
75. 45 
75.1 
75.3 
TE-T OF JAN. 17. 191i 
1— . 
75. 75 
49L 33 
2. >2 
2.17 
:v_- 
- . 9 
514. 31 
7.37 
430. 
- 
75. 
1A. 
75.8 
2 32 
2. .54 
15. 51 
-1. 45 
508.22 
7.41 
428 
610.0 
573. 5 
74.6 
2 
76. 05 
513. 10 
2. >2 
3.85 
7.85 
-3. 49 
524. 13 
r.55 
44S.5 
77.3 
Av. 
75.9 
2.^2 
13. S7 
-1.74 
515. 55 
7.44 
434.6 
61L S 
a , o. a 
,5. 51 
Before each of these tests it was necessary to allow the water to 
accumulate for about a week, and as the weather was dry the water 
became rather foul: it carried trash and organic matter which 
appeared to give off gas. 
The lift, or difference of level on suction and discharge sides of 
pump, was approximately 7.5 feet for all these tests, which is the 
lift for which the pump was designed. The results obtained from 
the tests show the efficiency of the pump to be about 75.5 per cent. 
This is less than was shown by the official test of 1915. when for a 
lift of 7.15 feet the efficiency of pump was approximately 79 per 
cent. It is possible that the foulness of the water affected the results 
to some extent. The efficiency obtained is good in any event. 
COST OF OPERATION OF PLANTS. 
Information regarding the various pumping plants tested, as well 
as for some others for which data have been obtained from reliable 
sources, has been arranged in tabular form Table 38) and in graphic 
form in tigs. 5. 6. 7. S. and 9 . All but plants Xos. 19 and 21 have 
centrifugal pumps. The impellers of the pumps in plants Xos. 8 3 
9. 10. 11. 12. 2o. and 22 see Table 38 are a combination of the 
screw and centrifugal principles. Xos. 19 and 21 are screw pumps. 
Plants Xos. 1.2. and 3 are medium-grade steam plants having 
slide valve noncondensing engines. Plants Xos. -i and 5 have 
Corliss noncondensing engines. The former was not tested under 
the most favorable conditions, while the latter was: Xo. 5 has a 
much more elaborate pump than Xo. 4. Plant Xo. 6 has a cross- 
