LAND DEAINAGE BY MEANS OF PUMPS. 



47 



hence the static head on the pump may be only the difference in 

 level between the water in the canal and the water in the river. In 

 this case the pipe must have an opening at the highest point for use 

 in priming the pump. This opening will also be used to admit air 

 to break the seal, thus preventing water from flowing back by siphon 



h : '*=r ■ r 4 . . - ■ ■- , ' ■' j ' . " . '■ ' Lf— — fe 



No.l 



o 



No.3 



- c - <''". h=r:::-"% 



Section C-D _ 



section through A-B 



Wta. ■',.— Plan and elevation of pumping plant, in Muscatine-Louisa Levee and Drainage District, Iowa. 



action when the piunp is stopped, if the pumps equipped with this 

 type of discharge pipe- are driven by motors, a flap valve should be 

 • I on the end of the pipe to prevent the water from siphoning back 

 through ilif pump while it, is being primed, thus turning the motor 

 backward and overloading it. This valve need not fit tightly and 



