822 



FORESTRY AND IRRIGATION 



July 



A Nd. | centrifugal pump thai draws 

 water from a single well should have 

 ;M leasl a 6 inch suction pipe, and the 

 discharge pipe should gradually in- 

 crease 1 1 "Hi | inches al the discharge 

 opening'of the pump to 8 inches 3 feel 

 above the discharge opening, and con 

 tinue this size until the flume or dis- 

 charge conduit is reached. The dis- 

 charge pipe can be made <>f riveted 

 galvanized Iron, and the suction pipe 

 can be made either of standard pipe or 

 gi m id well casing. 



5. A centrifugal pump loses its ei 

 Science at oner if there is an air Irak 



--how 11 an efficiency of about 80 per 

 cent. 



METHOD oh' PRIMING PUMPS. 



A large number of pumping plants 

 are installed with foot valves at the 

 bottom of the suction pipe. When 

 these are provided, a centrifugal pump 

 is always ready to start after it is once 

 primed. The foot valves usually inter- 

 fen- \iT\ materially with the flow of 

 water into the pipe, and its is undoubt- 

 edly more economical to omit them 

 and place a Map valve at the upper end 

 of the discharge pipe which can be 



Fig. 4 Measuring weir at pumping plant near Garden City, Kansas. At the time the 

 photograph was taken the pumping plant was yielding 200 gallons of water per minute 



around the stuffing box. or at any 

 place in the suction pipe. Many cen- 

 trifugal pumps are now provided with 

 a wa - al around the stuffing gland 

 that = s the absence of leaks at 

 int. 

 A g centrifugal pump with en- 



show an effici- 



j -foot 



2 ^le stag _:al pumps.. 



bronze runner made 



in tv - so that the interior could 



be and smoothed, have 



lowered when it is desired to start the 

 pump. An ordinary cast-iron house 

 pump connected to the top of the cas- 

 ing of the centrifugal pump can be 

 used to prime the pump with water he- 



tore starting. 



PIPE FITTINGS. 



The suction pipe installed by those 

 who construct pumping plants is not 

 only usually too small for the re- 



but the and tees used 



are or dapted to 



