44 



BULLETIN 1067, II. S. DEPARTMENT OF AGRICULTURE. 



Table 37. — Tests of 12-foot Wood screw drainage -pump at New Orleans pumping station 



No. 1, Nov. 17, 1917. 



TEST OF NOV. 17, 19.16. 





Speed. 



Quantity pumped. 



Lift. 



Water 

 horse- 

 power. 



Meas- 

 ured 

 elec- 

 trical 

 horse- 

 power. 



Meas- 

 ured 



E. H. P. 



X0.94 = 



H.P. 



input 



to 



pump. 





No. 



Meas- 

 ured 



in 

 flume. 



Leak- 

 age to 

 Broad 

 Street 

 Canal. 



Leak- 

 age 

 through 

 station. 



Correc- 

 tion for 

 storage 



in 

 canal. 



Correc- 

 tion for 

 storage 

 in dis- 

 charge 

 basin. 



Cor- 

 rected 

 quan- 

 tity. 



Effi- 

 ciency 

 pump. 



1... 



2... 

 3... 



At. 



R.p.m. 

 73.7 

 74.1 

 74.1 

 74/0 



Sec.-ft. 

 457. 84 

 475. 73 

 481. 54 

 471. 70 



Sec.-ft. 

 1.7-1 

 1.74 

 1.74 

 1.74 



Sec.-ft. 

 3.26 

 3.74 

 4. 35 

 3. 78 



Sec.-ft. 

 21.18 

 11. 45 

 6.96 

 13.20 



Sec.-ft. 

 -0.90 

 -4.70 

 -4.34 

 -3.31 



482. 92 

 487. 96 

 490. 25 

 487. 11 



Feet. 

 7.59 

 7.48 

 7. 415 

 7.495 



416. 

 414. 5 

 412.5 

 413. 9 



585. 86 



586. 77 

 582. 52 

 585. 03 



551. 



552. 

 547.5 

 550. 2 



P.cl. 

 75.45 

 75.1 

 75.3 

 75.23 



TEST OF JAN. 17, 1917. 



1... 



75. 75 



491. 35 



2.82 



2.17 



18. 25 



-0.2S 514.31 



7.37 



"1 

 430. : 608. 5 



572.5 



75.0 



1A. 



75.8 



488. 80 



2.82 



2.54 



15.51 



-1.45 1 508.22 



7.41 



428.0 ' 610.0 



573. 5 



74.6 



2... 



76.05 



513. 10 



2.82 



3.85 



7.85 



-3. 49 i 524. 13 



7.55 



448.5 : 617.0 



580. 5 



77.3 



Av. 



75.9 



497. 75 



2.82 



2.85 



13.87 



-1.74 1 515.55 



7.44 



434.6 ; 611.8 

 1 



575. 5 



75.51 



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 figs. 5, 6, 7, 8, and 9). All but plants Nos. 19 and 21 have 

 centrifugal pumps. The impellers of the pumps in plants Nos. 8, 

 9, 10, 11, 12, 20, and 22 (see Table 38) are a combination of the 

 screw and centrifugal principles. Nos. 19 and 21 are screw pumps. 



Plants Nos. 1, 2, and 3 are medium-grade steam plants having 

 slide valve noncondensing engines. Plants Nos. 4 and 5 have 

 Corliss noncondensing engines. The former was not tested under 

 the most favorable conditions, while the latter was; No. 5 has a 

 much more elaborate pump than No. 4. Plant No. 6 has a cross- 



