Pilot operated control valves

摘要

A pilot operated control valve has a body with an inlet 18 and an outlet 20. A main valve poppet 24 is movable within the body to selectively control flow of fluid between the inlet and outlet. The main valve poppet has a flexible diaphragm 29 with a pilot passage 30 therethrough which is opened and closed by movement of a pilot poppet 44. The diaphragm 29 flexes due to a pressure differential that acts on the pilot poppet, which flexing compensates for adverse effects that the pressure differential has on the operation of the pilot poppet. <IMAGE>