Fluid pump dispenser

摘要

A fluid pump dispenser has a pump body (2) including a pump cylinder defining a pump chamber (4) with a valve controlled product inlet passage leading to the chamber. A manually reciprocable pump plunger (12) having a hollow stem (22) defining a discharge passage leading from the chamber (4) is slidably mounted in the body. A pump piston (26) is mounted on the inner end of the stem (22) for relative sliding movement. A plunger return spring (13) biases the plunger (12) into a raised position. The piston (26) is limited for relative sliding movement between discharge open and closed positions, the piston having an annular projection (28) defining a discharge valve seated in an annular groove (44) of a plug element fixedly mounted to the stem (22) at its inner end. A lost-motion effect is created between the piston (26) and the stem (22) which closes the discharge valve during the pressure stroke and opens the discharge during the intake stroke. The plunger element (12) is capable of being locked in up and down positions, an outer surface of the plug element sealing the inlet passage closed in the plunger lock-down position.