Valve actuator with hydraulic damper

摘要

A valve actuator for an associated valve which includes apparatus for opening and closing an associated valve and a first housing in which a first diaphragm is disposed to define first and second chambers on respective sides of the first diaphragm. The apparatus also includes a valve actuator having a housing in which is disposed a second diaphragm to define a third chamber. The valve actuator includes apparatus connecting the second diaphragm to the apparatus for opening and closing the valve; and fluid coupling apparatus connecting the second chamber and the third chamber. The apparatus for opening and closing the valve includes a crank arm carried on a shaft.