Venting seal for dispenser

摘要

A dispenser includes a container providing a cavity and a discharge opening at one end. A piston in the cavity has a peripheral wall portion sealing against the inner wall of the container and a centrally disposed passage therethrough. A sealing plug of resiliently deformable material is seated in the passage and has a peripheral flange about the front end adjacent the discharge opening. The flange bears upon the surface of the front wall of the piston about the passage to effect a seal therebetween. A filler push rod bears upon the surface of the sealing plug is movable to move the flange of the plug away from the surface of the piston to allow air to vent through the passage about the periphery of the plug.