Low residual inverted pumps, dispensers and refill units

摘要

A foam pump including a housing and a piston that reciprocates within the housing is disclosed herein. The piston has a hollow portion and an orifice through the wall of the piston. A first seal located proximate the upper end of the piston provides a seal between the piston and the housing. A liquid inlet is located in the side wall of the housing at a point lower than the top of the piston. A one-way liquid inlet valve is located proximate the liquid inlet and a one-way liquid outlet valve is located prior to the liquid outlet. A charge chamber is defined at least in part by the liquid inlet valve, the liquid outlet valve, a wall of the piston and a wall of the housing.

主权项

1. A pull pump comprising:
a housing; a piston that reciprocates within the housing; the piston having an outer wall and at least a portion of the center of the piston is hollow; the piston includes an orifice form the outer wall to the center of the piston; a first seal is located proximate the upper end of the piston to provide a seal between the piston and the housing; the first seal is located above the orifice in the piston wall; a liquid inlet in the side wall of the housing at a point lower than the top of the piston; a one-way liquid inlet valve; a liquid outlet having a one-way liquid outlet valve; a charge chamber defined at least in part by the one-way liquid inlet valve, the one-way liquid outlet valve, a wall of the housing and a wall of the piston; and a mixing chamber located downstream of the one-way liquid outlet valve;
wherein the charge chamber is dispensed by pulling the piston downward and recharged by moving the piston upward.