ABSTRACT
Reciprocating pumps comprise two major segments: a liquid end and a power end shows the distinction for a typical vertical plunger pump. Liquid end types are classified by the type of reciprocating element and its action where applicable. For usual designs of power pumps, the reciprocating motion approaches sinusoidal, giving a duplex flow characteristic of the form. Compressibility reduces pump capacity by retarding suction valve opening, as the liquid remaining in the “clearance volume” has first to expand to suction pressure. At constant speed, power varies nearly linearly with differential pressure. The “no load” power is the sum of mechanical losses (friction) and liquid end hydraulic losses for that flow. Reciprocating pumps will compress gas, but the pressure developed is limited by the usually large clearance volume. Unless the pump can discharge some gas during each stroke, it will not clear itself.
