Reciprocable member with anti-float arrangement

1. 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.

2. The valve arrangement as set forth in claim 1 , comprising a resilient member arranged to urge the valve member to one of the closed position and the open position.

3. The valve arrangement as set forth in claim 2 , wherein the resilient member contacts the piston.

4. The valve arrangement as set forth in claim 3 , wherein the piston is slidably mounted on the valve stem.

5. The valve arrangement as set forth in claim 4 , wherein the cylinder comprises a stop arranged to stop movement of the piston toward the first space.

6. The valve arrangement as set forth in claim 1 , wherein the piston is slidably mounted on the valve stem.

7. The valve arrangement as set forth in claim 6 , wherein the cylinder comprises a stop arranged to stop movement of the piston toward the first space.

8. The valve arrangement as set forth in claim 1 , wherein the valve spring retainer comprises a cam surface.

9. The valve arrangement as set forth in claim 1 , wherein the piston is always in flow communication with the first space.

10. An exhaust valve arrangement, comprising:

a cylinder having a top end;

an exhaust conduit connected to the cylinder by an opening in the top end of the cylinder, the opening comprising a valve seat;

a valve member comprising a valve stem and a valve head on the valve stem, the valve member being movable between a closed position in which the valve head is received in the valve seat and an open position in which the valve head is spaced from the valve seat, the valve stem having a spring retainer;

a resilient member in contact with the spring retainer and arranged to urge the valve member to a closed position; and

a piston mounted relative to the valve stem, the piston being disposed in a second cylinder in flow communication with the exhaust conduit and arranged such that a change in pressure in the exhaust conduit changes a degree of compression of the resilient member, the resilient member being in contact with the piston and, at all times, disposed between and separating the piston and the spring retainer so that there can be no contact between the piston and the valve spring retainer.

11. The exhaust valve arrangement as set forth in claim 10 , wherein the piston is slidably mounted on the valve stem.

12. The exhaust valve arrangement as set forth in claim 10 , wherein the cylinder comprises a stop arranged to stop movement of the piston toward the exhaust conduit.

13. The exhaust valve arrangement as set forth in claim 10 , wherein the piston is always in flow communication with the exhaust conduit.