WITHDRAWAL DISCHARGING PISTON PUMP

摘要

A pump assembly with a first pump which draws liquid from a reservoir and dispenses it to a second pump. The second pump receives the discharge from the first pump and air such that the second pump discharges both liquid and air. The first pump preferably has a piston movable in a first inner chamber and the second pump utilizes the same piston movable in a second outer chamber. Preferably, the second pump discharges in the withdrawal stroke, that is while moving from a retracted position to a withdrawn position.