Patent ID: 6170511
Filing Date: 2001-01-09
Classification: B60T,Y10T

Abstract:
A purge valve for expelling a liquid contaminant from a fluid conduit which is normally unpressurized but is at times pressurized with a gas which contains such liquid contaminant, said valve comprising:(a) a housing;(b) a diaphragm mounted within said housing;(c) a control chamber on a first side of said diaphragm;(d) an exhaust passage on a second side of said diaphragm;(e) a valve seat surrounding an upstream end of said exhaust passage, said valve seat positioned so that said diaphragm may seal against said valve seat;(f) a spring disposed at least partially within said exhaust passage on said second side of said diaphragm to provide a spring force on said diaphragm to press it away from said valve seat;(g) an annular chamber on said second side of said diaphragm, said annular chamber surrounding said exhaust passage, said annular chamber open to said exhaust passage when said diaphragm is unseated from said valve seat;(h) a relatively low impedance flow path connected to said control chamber, said relatively low impedance flow path connectable to such fluid conduit;(i) a relatively high impedance discharge flow path connected to said annular chamber, said relatively high impedance discharge flow path at least one of connected to said control chamber, connected to said low impedance flow path and connectable to such fluid conduit;so that when said valve is connected to such fluid conduit and whenever such fluid conduit is unpressurized said valve is open due to said spring force so that such liquid contaminant may drain from such fluid conduit through said high impedance discharge flow path to said annular chamber and thence be purged from said valve through said exhaust passage; andso that when such fluid conduit is pressurized for a brief time before said spring force is overcome by pressure in said control chamber, said valve remains open so that such liquid contaminant is forcefully expelled through said valve and after said brief time, when said pressure in said control chamber overcomes said spring force, said diaphragm is pressed against said valve seat so that said valve is closed.