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US 5,458,289 AGranted
Liquid dispensing apparatus with reduced clogging
AssigneeBespak PLC
InventorMiro S. Cater
Life of this patent
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AssigneeBespak PLC
InventorMiro S. Cater
Estimating the term…
A pump dispenser connected to a container of liquid has a first piston reciprocatable in a first cylinder for pumping a quantity of liquid at each depression of the piston. A valve member received within a channel in the first piston is spring biassed into a position in which a dispensing outlet is normally closed and is movable to release liquid in response to excess liquid pressure in the first chamber. A cylindrical extension to the valve member defines a conduit communicating with liquid in the container and is separable from the valve member to open a liquid inlet port for recharging the first chamber. A second piston is movable in tandem with the first piston and cooperates with a second cylinder to provide suction on a return stroke of the pistons which is utilised to remove residual liquid from a dispensing channel delivering pumped liquid to a nozzle. Residual liquid collected in the second chamber is returned to the container during the next subsequent actuating stroke of the pistons. An actuator mounted on the first piston communicates lost motion to the second piston and provides valve action for applying suction to the dispensing channel. The dispenser is particularly useful for water borne liquid products because its self cleaning action prevents clogging.
A method of dispensing liquid from a container comprising the steps of:
Apparatus for dispensing liquid from a container comprising a reciprocatable first pumping means having a first chamber of variable volume and operable during an actuating stroke in response to movement of an actuator to displace liquid from the first chamber and to recharge the first chamber with liquid from the container during a return stroke, a dispensing channel defined by the actuator and communicating between the first chamber and a first nozzle for conducting pumped liquid during the actuating stroke, a second pumping means operable during at least part of the actuating stroke and the return stroke respectively in response to movement of the actuator and defining a second chamber of variable volume such that the volume of the second chamber is decreased during the actuating stroke and increased during the return stroke, a first valve means operable to connect the second chamber to the dispensing channel during the return stroke to thereby withdraw by suction residual liquid from the dispensing channel into the second chamber and a second valve means operable to discharge fluid from the second chamber during a next subsequent actuating stroke.
Dependencies are inferred from the claim text.