Centrifugal Pumps. 



105 



usual masonry culvert under the road being thus dispensed 

 with. 



The theory relating to the discharge of these pumps, with 

 the result of experiments in connection therewith, will be 

 found in the papers in the * Transactions' of the Institution 

 of Civil Engineers, by Mr. Thompson, in 1871, vol. xxxii. ; 

 Mr. Parsons, in 1876, vol. xlvii. ; Mr. Unwin, in 1877, 

 vol. liii. 



The various sizes of these pumps are generally described 

 from the diameter of the inlet pipes. Thus a " 30 inch 

 pump" would be one having a suction pipe 30 inches in 

 diameter at the inlet to the pump. 



With the best class of pumps with low lifts, such as are 

 required for drainage purposes, the following may be taken 

 approximately as the rate of discharge. The amounts given 

 are, however, above those attained by the pumps in ordinary 

 use : — 





Diameter ofSuc- 









tioiT. and Discharge 



Water discharged per Minute. 







Pipe, m Inches. 











Gallons. 



Ton& 







15 



5,000 



22*32 







18 



7,000 



31*25 







24 



11,000 



49 lo 







30 



18,000 



So-35 







36 



20,000 



89*28 







42 



27,000 



120 53 







48 



40,000 



i7S'57 







54 



70,000 



312-50 







60 



100,000 



446 43 





