590 



HYDRAULICS AND ITS APPLICATIONS 



Deep Well Pumps. Where pumping operations are necessary in a deep 

 well or bore hole of small diameter, the ordinary lift pump with separate 



foot valve is at a dis- 

 advantage because of 

 the great difficulty 

 which is experienced 

 in raising and replacing 

 this foot valve should 

 it become choked or in 

 any way out of order. 

 To obviate this diffi- 

 culty the " Ashley " 

 pump, Fig. 279, carries 

 both suction and de- 

 livery valves in its buc- 

 ket, this being readily 

 withdrawn for exami- 

 nation through the 

 rising main. 



The bucket B, which 

 is open at its lower 

 end, reciprocates in the 

 working barrel W.B., 

 which is closed at the 

 bottom. The sides of 

 this barrel are pierced 

 by orifices S.O. through 

 which the surrounding 

 fluid is admitted to the 

 under side of the suc- 

 tion valves S. V. On 

 the upward stroke of 

 the pump a partial 

 vacuum is formed in- 

 side the bucket, and 

 water is drawn through 

 these valves to fill the 



space inside and below 



FIG. 279. Single-Acting "Ashley " Bore-Hole Pump. 



the bucket, while the water above the bucket is forced up the rising main. 

 On the downward stroke the delivery valves D.V. open, and the water in 



