Liquid dispensing pump having water seal

摘要

A manually actuated pump dispenser has a water seal for maintaining the container vent ports sealed closed during pumping until at or near the end of the pressure stroke whereupon a vent path through which only air is permitted travel into the container, is open as the path is shielded against water entering the vent path when pumping in a wet environment as when dispensing hair shampoo or hair conditioner. In a plunger lock-down position of shipping and storage, leakage of product through the vent ports is substantially avoided during a superatmospheric condition within the container.