CENTRIFUGAL PUMPS 681 



of 16 feet. A model is made and delivers 1 cubic foot per second against 

 16 feet head when making 1,450 revolutions per minute, then giving its 

 maximum efficiency. The radius of the model impeller is 4'5 inches. 

 Determine the speed and radius of the large pump for maximum efficiency. 



Radius = 22'5 inches. 



Answer. , revolutions> 



(6) The peripheral speed of a centrifugal pump = 30 f.s. The vanes 

 are curved backward so that the discharge angle y = 35, while the water 

 leaves the wheel with a radial velocity of 5 f.s. If 120 cubic feet of water 

 pass through the pump per minute, determine the hydraulic turning 

 moment on the shaft if the radius of the wheel is 2 feet. 



Answer. 177 foot pounds. 



