Patent ID: 8079339

Claim:
A valve arrangement, comprising: a valve member comprising a valve stem and a valve head having a first and a second side on the valve stem; a wall between a first space and a second space, the first and second sides of the valve head facing the first and second spaces, respectively, an opening in the wall defining a valve seat, the valve member being movable between an open position in which the valve head is disposed in one of the first space and the second space and a closed position in which the valve head is disposed in the valve seat; a piston mounted relative to the valve stem, the piston being disposed in a cylinder in flow communication with the first space; a valve spring retainer on the valve stem, the valve spring retainer comprising a cam surface; and a resilient member arranged to contact the valve spring retainer and urge the valve member to the closed position, wherein the resilient member, at all times, is disposed between and separates the piston and the valve spring retainer so that there can be no contact between the piston and the valve spring retainer.