Metering pump, metering pump plunger head and metering pump spout

摘要

A discharge valve assembly (12,202) fitted to a spout (22,212) for permitting selective outletting of liquid product through the spout (22,212) during each of the pressure strokes. The spout (22,212) includes a bore (36,226) having a predetermined diameter, with a unitary valve disposed substantially within the bore (36,226). The unitary valve is made of a material for permitting predetermined axial, or axial and radial expansion thereof under pressure from liquid product during each of the pressure strokes for thereby allowing liquid product to be discharged through a slitted opening (46,236) in the unitary valve, and enabling rapid contraction thereof against a valve seat (56,242) to prevent liquid product from being discharged through the slitted opening (46,236).