<p>A valve for rapidly filling and emptying a volume created by rapid displacement of a machine member. The valve has a body to be connected between a reservoir and the machine. The valve has a valve seat with a seating surface that surrounds the flow path of fluid from the volume and an integral valve guide connected to the seat. A valve opening toward the machine is spring urged toward closed position to withstand high pressure of the fluid at the machine. An auxiliary mechanism is provided to open the valve which may be a solenoid, a pilot piston, or fluid cylinder or manual operation. The valve is provided with a dashpot to provide smooth operation.</p>
