chapter  11
12 Pages

POSITIVE-DISPLACEMENT PUMPS

The reciprocating pump (or piston pump) is one type of positive-displacement pump. This pump works just like the piston in an automobile engine-on the intake stroke, the intake valve opens, filling the cylinder with liquid. As the piston reverses direction, the intake valve is pushed closed, and the discharge valve is pushed open; the liquid is pushed into the discharge pipe. With the next reversal of the piston, the discharge valve is pulled closed, and the intake valve is pulled open; then, the cycle repeats.