Patent ID: 6564968
Filing Date: 2003-05-20
Classification: G01F

Abstract:
An automatic fluid dispenser comprising:a pump mechanism including a housing defining a pump chamber having a fluid inlet coupled to a fluid source and a fluid outlet, an inlet check valve mounted in the fluid inlet of the pump chamber for allowing fluid to flow only into the pump chamber from the fluid source, and an outlet check valve mounted in the fluid outlet for allowing fluid to flow only out of the pump chamber to the fluid outlet, the inlet check valve being normally biased into a closed position; a reciprocating element positioned within the pump chamber for reciprocating motion between a first position in which the pump chamber has a first volume and a second position in which the pump chamber has a second, smaller volume causing fluid contained in the pump chamber to be dispensed, the reciprocating element defining a pressure receiving surface; a biasing element included in the pump mechanism for biasing the reciprocating element into the first position; a pressurized fluid conduit couplable to a pressurized fluid source and coupled to the pressure receiving surface of the reciprocating element to supply pressurized fluid to the pressure receiving surface of the reciprocating element for moving the reciprocating element from the first position to the second position; a valve carried by the pressurized fluid conduit and movable between an open position in which a pressurized fluid from the pressurized fluid source moves the reciprocating element to the second position, and a closed position stopping the pressurized fluid; a pressurized fluid bleed coupled to the pressurized fluid source adjacent the pressure receiving surface for relieving pressure on the pressure receiving surface when the valve is in the closed position to allow the biasing element to return the reciprocating element to the first position; and a sensor for actuating the valve from the closed position to the open position, the valve being normally biased to the closed position.