SPRAY UJIiKJATION. 



27 



for pumping from surface supplies to any height. They can be 

 driven by either belt or gear connection to the power. 



Triplex or three-cylinder pumps are adapted for pumping water 

 from surface supplies to any height of lift for the larger plants. For 

 special well conditions triplex pumps are designed for the three 

 cylinders to work in a pit while the power working head remains on 

 the surface. These also can be driven by belt or gear connection to 

 the power. 



Small displacement 

 pumps of the belt- 

 driven types should be 

 equipped always with 

 tight and loose pulleys 

 to aid in starting the 

 engine. For the same 

 reason large outfits 

 should be equipped 

 with friction -clutch 

 pulleys on the shaft if 

 belt driven and shaft 

 clutches if gear con- 

 nected. Clutches are 

 not so essential where 

 electric power is used 

 for either small or 

 large plants. All clis- 

 placement pumps 

 should be equipped 

 with ample air cham- 

 bers to act as cushions 

 in absorbing the pulsa- 

 tions of the water. 

 Relief valves or by-passes should be placed in the discharge pipes to 

 prevent breaking the pumps or engines should all or a part of the 

 spray lines be shut off. 



Fig. 17. — Typical power working-head for deep-well 

 pumps having a 24-inch stroke. 1, Air chamber ; 

 2, crosshead guides ; 3, piston rod ; 4, connecting rod ; 

 5, packing gland ; 6, tight and loose pulleys ; 7, gear 

 wheel ; 8, base ; 9, discharge opening. 



CENTRIFUGAL PUMPS. 



Centrifugal pumps can be classified as volute and turbine types. 

 Each type can be divided further into pumps having one, two, etc., 

 stages, according to the number of impellers contained. Figure 18 

 shows a t}^pical single-stage volute-type pump with exposed im- 

 peller. Single-stage pumps are built in both volute and turbine 

 types for any lift practical for spray irrigation ; however, the possible 



