Gas purge valve

A gas purge valve comprising first and second valve housing components rigidly secured at peripheral flange portions thereof to form a valve housing;

• a diaphragm having a central, relatively rigid portion and an outer, relatively resilient annular portion clamped between said peripheral flange portions and defining, with said first and second valve housing components, first and second chambers;
• a valve inlet and a major valve outlet formed in said first housing component and communicating with said first chamber;
• a minor valve outlet formed in said second housing component and communicating with said second chamber;
• a throughgoing aperture being formed in said relatively rigid portion and constituting a flow passage between said first and second chambers having a throughflow rate less than that of said minor valve outlet;
• said diaphragm being juxtaposed with respect to said major valve outlet so as to bear normally into sealing it and to be flexibly displaceable away from it so as to open said major valve outlet;
• a minor valve outlet casing forming part of said minor valve outlet and mounted on said second valve housing component;
• a float located in said outlet casing;
• first and second float seatings formed in said casing respectively defining first and second throughflow ports respectively opening to the atmosphere and to said second chamber;
• at least said first float seating being such that when said float bears against it, its associated throughflow port is sealed against fluid throughflow from the other throughflow port via said casing.

A gas purge valve for use in a sewage flow system and comprising a valve housing having a valve inlet and major and minor valve outlets;

• a diaphragm flexibly mounted in said housing and juxtaposed with respect to said major valve outlet so as to bear normally against it to seal it and so as to be flexibly displaceable away from it so as to open it;
• said diaphragm serving to divide said housing into a first chamber communicating with said valve inlet and said major valve outlet and a second chamber communicating with said minor valve outlet;
• a throughgoing aperture being formed in said aperture and constituting a flow passage between said chambers having a throughflow rate less than that of said minor valve outlet;
• an outlet casing forming part of said minor valve outlet and mounted on said second valve housing component;
• first and second casing seatings respectively opening to the atmosphere and to said second chamber;
• a sealing member located in said casing and displaceable between a first position wherein it bears on said second seating so as to allow gas flow from said second chamber through said casing to the atmosphere, and a second position wherein the casing is sealed against fluid throughflow from said chamber;
• a float member located in said first chamber and adapted to float on liquid sewage therein and a coupling rod serving to couple said float member to said sealing member and serving to transmit upward and downward displacements of said float member to said sealing member so as respectively to close and open said minor valve outlet.