VALVE SEATING CONTROL DEVICE WITH VARIABLE AREA ORIFICE

摘要

A system for decelerating a linearly displaceable valve undergoing a closing motion is disclosed. The system includes a housing, a first hydraulic fluid chamber (312) provided in said housing, and a slave piston (320) for displacing the valve in response to the supply of hydraulic fluid to the first hydraulic fluid chamber (312). Deceleration of the valve may be accomplished by selectively throttling the release of hydraulic fluid in the first chamber (312) to a second chamber (336). The hydraulic pressure in the second chamber (336) opposes the closing motion of the valve, thereby slowing it gently for a valve seating event. Progressive throttling is used to maintain nearly constant hydraulic pressure in the second chamber (336) during the seating event. The progressive throttling may be accomplished by selection of an appropriate throttling orifice (344) size and shape, as well as an appropriate throttling profile for the orifice (344).