TESTS OF DEAINAGE PUMPING PLANTS. 



17 



Table 9. — First test of pumping plant in subdistrict No. 1, Lafourche drainage district 



No. 6, Nov. 23, 1912. 



UNIT NO. l. 





Boiler 

 pressure. 



Speed. 



Indi- 

 cated 

 horse- 

 power. 









Water 

 horse- 

 power. 



Efficiency. 



Time. 



Actual 

 lift. 



Discharge. 



Pump, 

 engine, 



and 

 piping. 



Pump 



and 

 piping.i 



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 



7?. p. m. 

 164 

 168 

 172 

 174 

 173 

 184 

 170 

 162 

 179 



Feet. 



40.6 ! 2.60 



46.4 : 2.65 



46.7 . 2.72 



48. J 2. 84 



49.1 I 2.95 



55. 5 3. 07 

 44. 3 3. 17 



37.6 1 3.29 

 53.0 3.42 



Sec.-ft. 

 36.5 

 40.5 

 38.7 

 40.7 

 39.1 

 41.1 

 37.5 

 34.5 

 40.0 



G. p. 77? . 



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 2.0 and 3.4 feet, and the pumps were operated at about 30 

 per cent over their rated capacities. While this information was 

 \ Billable in showing overload capacity and the efficiency of the pumps 

 at low lift, it was 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 I 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 .")() per cent overload and shows (lie 

 reduction in efficiency thai 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. 



99782 22 Hull. 1007 3 



