Rotor valve and seal

• US 20040140445A1
• Filed: 12/19/2003
• Published: 07/22/2004
• Est. Priority Date: 01/16/2003
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Pervaiz, Muhammad
• Granted Patent: US 6,994,316 B2
• Time in Patent Office: Days
• US Class Current: 251/160
• CPC Class Codes: F01P 2007/146 using valves
• CPC Class Codes: F16K 11/085 with cylindrical plug
• CPC Class Codes: F16K 11/0856 having all the connecting conduits situated in more than one plane perpendicular to the axis of the plug
• CPC Class Codes: F16K 31/1635 for rotating valves
• CPC Class Codes: F16K 5/0478 on the plug

Abstract

A rotor valve (10) having a rotor seal (34) containing a centrally disposed opening (52) for directing an external pressure (P_e) to a rear surface (35) of the seal for applying a sealing force against a sealing surface (36). A projection (38) of the seal surrounding the opening is disposed within a bore (40) formed in a rotor (14) of the valve. An O-ring seal (44) defines the portion of the rear surface exposed to the external pressure. The rotor may be supported on one end by a bearing assembly (80) and may be open at the opposed end for receiving incoming water. Circumferentially distributed slip-surface plugs extend radially beyond the diameter of the rotor to support the rotor along an interior surface (39) of the valve body (12).

Claims

1. A rotor valve comprising:

a valve body comprising a rotor chamber and a plurality of openings for the passage of fluid;

a rotor disposed within the rotor chamber, the rotor comprising at least one passageway for controlling fluid flow through the chamber;

a seal carried on the rotor presenting a sealing surface engageable with an interior surface of the valve body proximate a selected valve body opening for restricting fluid flow through the selected valve body opening and further presenting a rear surface at a side of the seal generally opposed to the sealing surface; and

a passageway formed in the seal directing pressurized fluid from the selected valve body opening to the rear surface of the seal to exert a sealing force urging the sealing surface against the valve body into sealing engagement.

2. The rotor valve of claim 1, further comprising a spring member urging the sealing surface against the valve body.

3. The rotor valve of claim 1, wherein the rotor further comprises a bore in an outer surface thereof and presenting a side wall defining the bore, and the seal further comprises:

a projection extending into the bore; and

a sealing member disposed about a perimeter of the projection and providing a fluid barrier between the seal and the side wall of the bore, the sealing member defining an area of the rear surface of the seal exposed to the pressurized fluid.

4. The rotor valve of claim 3, further comprising a spring member disposed between the rotor and the seal within the area exposed to the pressurized fluid, the spring member urging the sealing surface against the valve body.

5. The rotor valve of claim 3, further comprising a spring member disposed between the rotor and the seal outside the area exposed to the pressurized fluid, the spring member urging the sealing surface against the valve body.

6. The rotor valve of claim 3, wherein the passageway comprises a centrally disposed opening formed through the projection.

7. The rotor valve of claim 1, wherein the rotor is supported within the valve body at a first end by a bearing and at a second end opposed the first end by a plurality of circumferentially distributed slip-surface members extending into an annular space between the rotor and valve body for sliding contact of the rotor in the valve body to support the rotor.

8. The rotor valve of claim 1, further comprising an actuator coupled to the rotor by a shaft for rotating the rotor between a plurality of positions within the valve body, the actuator further comprising:

a rack coupled to the shaft by a pinion gear;

a first piston connected to the rack and disposed within a first cylinder for moving the rack in response to pressure applied within the first cylinder;

a second piston disposed within a second cylinder; and

a stop moveable with the second piston in response to pressure within the second cylinder to a position determining a position of the rotor by restricting a range of motion of the first piston.

9. The rotor valve of claim 8, wherein a diameter of the second piston is greater than a diameter of the first piston.

10. The rotor valve of claim 1, wherein the seal comprises a glass impregnated polytetrafluoroethylene material.

11. A seal assembly for sealing a valve body opening of a rotary valve having a rotor fitted within a valve body, the seal assembly comprising:

a body having a portion sized to fit within a bore in a rotor of a rotary valve and comprising a rear surface to be at least partially disposed within the bore and comprising a sealing surface opposed the rear surface for contacting an interior of the valve body surrounding the valve body opening;

a passageway formed in the body from the sealing surface to the rear surface for conveying a fluid pressure from the valve body opening to the rear surface for exerting a sealing force on a portion of the rear surface disposed within the bore; and

a sealing member disposed about a perimeter of the body within the bore in the rotor and defining at least in part the portion of the rear surface exposed to the fluid pressure.

12. The seal assembly of claim 11, further comprising a spring member for exerting a sealing force on the body.

13. The seal assembly of claim 12, further comprising a recess formed in the body for receiving the spring member.

14. The seal assembly of claim 13, wherein the recess is disposed in the rear surface within the portion of the rear surface exposed to the fluid pressure.

15. The seal assembly of claim 13, wherein the recess is disposed in the rear surface outside the portion of the rear surface exposed to the fluid pressure.

16. The seal assembly of claim 11, wherein the body comprises a glass impregnated polytetrafluoroethylene material.

17. The seal of claim 12, wherein the spring member comprises a spring, and further comprising a recess formed in the body for receiving the spring.

18. The seal of claim 11, wherein the sealing member comprises an O-ring seal.

19. The seal of claim 11, wherein the passageway comprises a centrally disposed opening formed through the seal body.

20. The seal of claim 19, wherein the passageway further comprises a recessed area formed along the rear surface in fluid communication with the centrally disposed opening.

21. An actuator operated by fluid under pressure for selectively positioning a rotor of a rotary valve in any one of at least three positions, the actuator comprising:

a carriage adapted for connection to a rotor of a rotary valve, the carriage comprising a first piston disposed in a first cylinder for providing a range of motion to rotate the rotor between a first position and a second position in response to fluid pressure within the first cylinder; and

a stop selectively moveable from a withdrawn position to an extended position to restrict the range of motion of the carriage when the stop is in its extended position to provide a third position of the rotor intermediate the first position and the second position.

22. The actuator of claim 21, wherein the stop is connected to a second piston disposed within a second cylinder to move the stop in response to fluid pressure within the second cylinder.

23. The actuator of claim 22, further comprising:

a common supply of fluid under pressure selectively providing fluid under pressure to each of the first cylinder and the second cylinder; and

wherein

a surface area of the second piston is greater than a surface area of the first piston so that a force exerted by the first piston is not sufficient to displace the stop from its extended position when the fluid under pressure is present in both the first cylinder and the second cylinder.

24. The actuator of claim 22, wherein the surface area of the second piston is at least 1.4 times the surface area of the first piston.

25. A rotor for a rotary valve having a valve body comprising:

a cylindrical shaped rotor rotatable about a longitudinal axis within the valve body;

a bearing support disposed along the axis at a first longitudinal end of the rotor for cantilevered support of the rotor within the valve body; and

an inlet opening formed in the rotor generally along the axis at a second longitudinal end of the rotor opposed the first end.

26. The rotor of claim 25, further comprising a plurality of circumferentially distributed slip-surface members extending radially in an annular space between the rotor and the valve body proximate the second longitudinal end for providing support for the rotor.

27. The rotor of claim 26, wherein the slip-surface members are plugs of low coefficient of friction material carried on the rotor at an outer surface thereof.