Accumulator release pump

Abstract

A finger operated accumulator release pump, adapted to be mounted on a container to dispense liquid therefrom only after the liquid has been pressurized by a predetermined amount, comprises a housing which defines a pump chamber and an inlet to the pump chamber. A conventional check valve prevents return flow of liquid through this inlet. A plunger is telescopically received for reciprocal pumping action in the pump chamber, makes a sliding piston fit with it, and is provided with an outlet passage and a valve seat at the inlet end of the outlet passage. The pressure accumulating release feature of the pump is provided by cooperation of an outlet passage by-pass arrangement and a pressure actuated accumulator valve. The by-pass arrangement comprises a number of by-pass grooves which are disposed in a generally axial direction on the inner surface of the outlet passage at a location intermediate its ends. The accumulator valve member is mounted for reciprocal movement in the outlet passage between a closed position sealed against the inner wall of the outlet passage or against the valve seat and an open position adjacent the by-pass grooves where it permits liquid to be forced through them. A return spring urges the accumulator valve to its closed position. Accordingly, liquid is dispensed by this pump only after liquid in the pump chamber has been pressurized sufficiently to reciprocate the valve member to its open position against the force of the return spring. Further, dispensing stops immediately when liquid pressure drops sufficiently to permit the valve member to again block the by-pass grooves.