DISCHARGE VALVE CONTROL FOR VISCOUS PRODUCT DISPENSER

摘要

A viscous product dispenser has a positive discharge valve (28) which is opened upon a lost motion arrangement between the spout (25) and the pump piston (12) at the initial actuation of the spout. The lost motion is effected by spaced apart stops on these two members permitting limited sliding movement relative to the pump piston (12) for opening the discharge valve (28) before the pumping movement of the piston. A piston return spring (27) is external to the pump chamber (11) for biasing the discharge valve (28) to a closed position. A stop ring on the piston head may be provided for bearing engagement with an end wall of the container on which the container is mounted for isolating the load on the piston.