A Plunger pump has a reciprocating plunger. This Plunger is connected to cross head, which in turn connects to a crank shaft which provides the reciprocating action. As the Plunger stokes back, the fluid is pulled into the cylinder through an inlet check valve. As the plunger reciprocates to its foward stroke, the inlet valve closed and the liquid is forced out of the discharge check valve.
The Plunger reciprocates inside a stuffing box, which is typically fitted with rings of packing to seal plunger. A Piston differs from a Plunger, as the packings or seal if fitted to the piston and reciprocates with it inside a sleeve/cup.
This Piston and Plunger pumps provide a pumping solution which lends itself to typically low flow, high pressure applciations.
FMC Simplex, Duplex, Triplex and Quintuplex Plunger pumps and piston pumps are available in the UK from AxFlow