Valve stem and valve core assembly and valve comprising the assembly

1. A valve, comprising:

a valve body defining an inlet, an outlet, and a valve port disposed between the inlet and the outlet;

a valve stem and valve core assembly comprising:

a valve stem;

a valve core sleeving the valve stem, the valve core movably disposed within the valve body relative to the valve port;

an adjusting device sleeving the valve stem and housed entirely within the valve core, the adjusting device comprising an outer wall, an inner wall defining an opening sized to receive the valve stem, and a groove defined between the outer and inner walls;

an elastic element arranged between the adjusting device and the valve core, the elastic element arranged in the groove of the adjusting device such that the elastic element contacts both the adjusting device and the valve core to maintain axial clearance between the adjusting device and the valve core; and

a gap between the valve core and the valve stem such that the valve core is movable relative to the valve stem.

2. The valve according to claim 1 , wherein the adjusting device comprises a convex surface arranged in contact with a concave surface of the valve stem.

3. The valve according to claim 1 , wherein the valve core comprises a convex surface arranged in contact with a concave surface of the adjusting device.

4. The valve according to claim 1 , wherein the groove is a continuous annular groove which surrounds the valve stem, and the elastic element is an O-ring.

5. The valve according to claim 1 , wherein the adjusting device is fixed on the valve stem by a nut.

6. The valve according to claim 2 , wherein the valve core and the convex part of the adjusting device are concentrically fitted with one another.

7. The valve according to claim 3 , wherein the adjusting device and the convex part of the valve core are concentrically fitted.

8. The valve according to claim 1 , wherein the inner wall of the adjusting device comprises a thread to threadingly fix the adjusting device on the valve stem.

9. A valve, comprising:

a valve body defining a valve port;

an end flange removably coupled to the valve body such that a portion of the end flange is disposed outside of the valve body; and

a valve stem and valve core assembly comprising:

a valve stem;

a valve core sleeving the valve stem, the valve core movable between an open position and a closed position, the valve core having a first end and a second end, the first end arranged to sealingly and directly engage the valve port when the valve core is in the closed position, the second end arranged to directly engage a portion of the end flange when the valve core is in the open position;

an adjusting device sleeving the valve stem; and

an elastic element arranged between the adjusting device and the valve core;

wherein one end of the valve stem and the valve core pass through the valve port, the valve core being movable relative to the valve port responsive to movement of the valve stem, the valve core configured to sealingly engage the valve port, thereby closing the valve port.

10. The valve according to claim 9 , wherein the valve core of the valve comprises a piston or a clack valve.

11. The valve according to claim 9 , wherein the adjusting device or the valve core is provided with a groove and the elastic element is fitted in the groove.

12. The valve according to claim 9 , wherein the adjusting device comprises a convex surface arranged in contact with a concave surface of the valve stem.

13. The valve according to claim 9 , wherein the valve core comprises a convex surface arranged in contact with a concave surface of the adjusting device.

14. The valve according to claim 11 , wherein the groove is a continuous annular groove which surrounds the valve stem, and the elastic element is an O-ring.

15. The valve according to claim 11 , wherein the adjusting device comprises an outer wall and an inner wall defining an opening sized to receive the valve stem, the groove being defined between the outer and inner walls.

16. The valve according to claim 9 , further comprising a gap between the valve core and the valve stem such that the valve core is movable relative to the valve stem.

17. The valve according to claim 9 , further comprising a fastener arranged to fix the adjusting device on the valve stem, the fastener housed entirely within the valve core.

18. The valve according to claim 9 , wherein the adjusting device is housed entirely within the valve core.

19. The valve according to claim 9 , wherein the end flange is removably coupled to the valve body via a plurality of fasteners.

20. A valve stem and valve core assembly for use with a control valve, the assembly comprising:

a valve stem;

a valve core sleeving the valve stem, the valve core comprising a cylindrical wall;

an adjusting device sleeving the valve stem, the adjusting device surrounded by the cylindrical wall and housed entirely within the valve core;

an elastic element arranged between the adjusting device and the valve core, wherein the elastic element contacts both the adjusting device and the valve core to maintain axial clearance between the adjusting device and the valve core;

a gap between the valve core and the valve stem such that the valve core is movable relative to the valve stem,

wherein the cylindrical wall has a first end and a second end opposite the first end, and wherein the valve core further comprises a base portion arranged between the first and second ends and surrounded by the cylindrical wall, the base portion defining an opening sized to receive the valve stem, the adjusting device seated against a portion of the base portion; and

a fastener arranged to fix the adjusting device on the valve stem, wherein the adjusting device is arranged entirely between the fastener and the base portion of the valve core.