Manually actuated pump having pliant piston

Abstract From the Canadian patent

A dispensing pump of the pressure accumulating type includes an assembly of a pump body and a separate piston member the body including a closure cap for securing the assembly in fluid tight communication with the opening of a container of flowable product to be dispensed, a plunger/accumulator forming a variable volume pump chamber together with the piston and being reciprocable relative thereto, and a plunger head surrounding the plunger. The ?, plunger has a vent seal for opening and closing a vent chamber defined around the piston. The closure cap is of a hard and durable material, while the separate piston is softer and more compliant which gives its lip seal good definition which …