Patent ID: 6217001
Filing Date: 2001-04-17
Classification: F02M

Abstract:
A valve for metering gas, said valve comprising:a valve body including a passage, the valve body having a valve seat internally defining a flow orifice that is closable to cut off gas flow through the passage;a cylinder open to the passage and axially aligned with the valve seat orifice;a valve member in the passage and including a valve head engagable with the valve seat to close the orifice;a piston on the valve member and slidable in the cylinder, the piston and the valve head having, when the valve is closed, opposing approximately equal axially projected cross-sectional areas exposed to the passage for balancing the effects of varying pressure in the passage on the valve member; andseal means between the piston and the valve body for limiting leakage past the piston and cylinder;wherein said seal means includes a floating bushing defining said cylinder and slidably receiving said piston, said bushing having a flange slidably engagable with a sealing surface of the valve body and allowing limited lateral motion of the bushing for alignment with the piston; anda biasing member urging the floating bushing axially to force the flange of the bushing against the sealing surface of the valve body for preventing leakage of fluid past the piston between the cylinder and the valve body. body.