Patent ID: 7975722

Claim:
A one way valve assembly that comprises: an inlet and an outlet, a flow pathway that extends through the valve assembly from the inlet to the outlet, a plunger that is positioned in the flow pathway and which can move between a forward open position where fluid can flow from the inlet to the outlet, and a retracted closed position where fluid flow is reduced or prevented from flowing from the inlet to the outlet, an at least partially elastic diaphragm that has an outer end fixed to the valve assembly, and an inner portion which engages with the plunger such that reciprocation of the plunger from the retracted position to the forward position causes at least part of the diaphragm to stretch, a variable volume chamber having walls at least partially defined by the plunger and the diaphragm, the chamber forming part of the flow pathway, the chamber having smaller or nil volume when the plunger is in the retracted position, and a larger volume when the plunger is in the extended position, whereby upon retraction of the plunger, the variable volume chamber reduces in volume which results in a pumping action to pump fluid through the fluid pathway towards the outlet, thereby reducing or preventing backflow, and a resilient end valve positioned within the flow pathway adjacent the inlet and supported by a spacing member, the spacing member being co-axially aligned with the flow pathway and attached to the plunger, the resilient end valve being movable between an open flexed position enabling fluid to flow towards the outlet of the valve, and a closed rest position preventing backflow of fluid through the inlet, wherein the resilient end valve is moved to the open flexed position by the flow of fluid, and the resilient end valve is moved to the closed rest position by the absence of flow of fluid.