Patent ID: 6422434
Filing Date: 2002-07-23
Classification: B05B,B05C,F16K,G01F

Abstract:
A dispenser pump for fluid material having a pump chamber alterable in volume by the action of a reciprocable plunger, a pump chamber inlet having an inlet valve, a pump chamber outlet having an outlet valve arrangement and a discharge nozzle defining a discharge passage extending downstream of the outlet valve arrangement;the outlet valve arrangement having a blocking element which is movable along the discharge passage between a closed valve condition at an upstream position and an open valve condition at a downstream position, the outlet valve arrangement defining a restricted draw path extending along the discharge passage between said upstream and downstream positions and dimensioned to be substantially blocked by the blocking element, the outlet valve arrangement further comprising a spring member, the blocking element being biased by said spring member towards the upstream position, whereby upon displacement of the plunger to reduce the volume of the pump chamber the blocking element is drivable along the draw path against the bias of said spring member to the downstream position for dispensing said fluid material in the valve open condition, and upon discontinuing displacement of the plunger the blocking element is driven back along the draw path under the bias of said spring member to drive material back into the pump chamber and draw residual material back along the discharge passage.