Patent ID: 6253972
Filing Date: 2001-07-03
Classification: B05C

Abstract:
A valve for dispensing liquid under pressure, comprising:a valve housing,a valve pin positioned in the valve housing for axial reciprocation, the pin having a valve closure end and an opposite, upper end,a valve orifice at a downstream end of the valve housing,a valve seat adjacent to the valve orifice and positioned essentially coaxial with the valve pin, for closure of the valve when the valve pin is engaged against the valve seat, and the housing defining a liquid chamber upstream of the orifice and surrounding the valve pin near its valve closure end,a pin slide fitting in the housing and defining an end of the liquid chamber, the valve pin passing through an opening in the slide fitting for reciprocating sliding movement relative to the fitting,electromagnetic retraction means connected to the valve pin for axially retracting the pin away from the valve seat and opening the valve when power is applied to the retraction means,a liquid supply channel leading into the liquid chamber and having an upstream end with means for connection to a supply of pressurized liquid, anda bellows member having corrugations oriented transversely to the axial direction of the valve pin, the bellows member being positioned in surrounding relationship to the valve pin and having one end secured to the valve pin in sealed relationship near the downstream end of the valve housing and an opposite end secured in sealed relationship to the pin slide fitting through which the valve pin is reciprocal,the bellows exerting a spring force on the valve pin sufficient to retain the valve pin in closed position against the valve seat under a preselected range of liquid pressure conditions in the liquid chamber, while also providing a seal against leakage of the pressurized liquid along the pin, toward the retraction means.