14 



BULLETIN 1067, IT. S. DEPARTMENT OF AGRICULTURE. 



into the water. By way of comparison, in the test made at Gueydan, 

 La., at the pumping plant of Subdistrict No. 1, Gueydan drainage 

 district, the loss of head corresponding to those given above amounted 

 to 0.3 foot. 



SECOND TEST. 



A second test was made to determine the efficiency of engine, 

 pump, and piping. This test was of special interest, inasmuch as 

 changes had been made in the suction and discharge pipes of two 

 pumps since the previous test of October 19, 1912. The intake ends 

 of the suction pipes and the exit ends of the discharge pipes as origi- 

 nally constructed were very poorly designed. Since the first test 

 was made the pipes had been replaced by others with well-designed 

 ends. The side clearance of the open impeller of the 36-inch pump, 

 which had been nearly three-fourths inch, had been reduced to about 

 one-eighth inch, and the impeller blades in both pumps had been 

 lengthened. 



The changes were beneficial to plant efficiency, although it is diffi- 

 cult to say how much each contributed to the improved conditions. 

 Lengthening the impeller blades and decreasing the clearance gave 

 more water for a given lift and number of revolutions, while the 

 elimination of entrance and discharge losses decreased the total head 

 on pump. The second test was run at a greater lift than was the 

 first, and this also contributed to the higher efficiency. The results 

 of the test are given in Table 6, and a comparison made with the 

 first test in Table 7. 



Table 6. — Second test of Phillips Land Co. pumping plant, Aug. 11, 1916. 



36-INCH UNIT. 



Time. 



Speed. 



Indi- 

 cated 

 horse- 

 power. 



Actual 

 lift. 



Discharge. 



Useful 

 water 

 horse- 

 power. 



Efficiency 



engine, 

 pump, 



and 

 piping. 



11.15 



R.p. 771. 

 146 

 146 

 146 

 146 

 146 

 138 

 137 

 136 

 135 

 141 

 154 

 153 

 154 

 153 

 160 

 160 

 160 



81.20 

 81.25 

 78.80 

 78.60 

 80.30 

 67.20 

 65.72 

 62.95 

 61.70 

 71.65 

 93.15 

 89.10 

 91.60 

 91.35 

 103. 25 

 102.50 

 101. 90 



Feet. 

 5.90 

 5.95 

 6.00 

 6.05 

 6.10 

 6.12 

 6.14 

 6.16 

 6.18 

 6.13 

 6.20 

 6.23 

 6.25 

 6.29 

 6.35 

 6.38 

 6.42 



Sec.-ft. 

 64.21 

 63.00 

 61.40 

 62.13 

 62.75 

 48.53 

 47.18 

 43.76 

 43.08 

 59.20 

 69.06 

 69.03 

 69.21 

 68.62 

 74.48 

 74.00 

 74.08 



G.p.m. 

 28,800 

 28,300 

 27, 600 

 27, 900 

 28, 200 

 21, 800 

 21, 200 

 19,650 

 19, 350 

 26,600 

 31, 050 

 31, 000 

 31,100 

 30, 800 

 33,400 

 33, 250 

 33,300 



42.90 

 42.50 

 41.70 

 42.50 

 43.30 

 33.65 

 32.75 

 30.55 

 30.20 

 41.10 

 48.50 

 48.70 

 49.00 

 48.90 

 53. 60 

 53.50 

 53. 80 



Per cent. 

 52.9 



11.20 



52.4 



11.25 



53.0 



11.30 



54.1 



11.35 



53.9 



11.40 



50.2 



11.45 



49.8 



11.50 



48.6 



11.55 



48.8 



12.35 



57.3 



12.45.. . 



52.0 



12.50 



54.7 



12.55 



53.5 



1.00 



53.5 



1.05 



51.8 



1.10 



52.2 



1.15 



52.9 







Mean 



148 



.76.6 



6.17 



61.98 27,817 



43.36 



52.45 



