Fluid flow device that provides a seal by exploiting differential thermal expansion

Patent metadata

Field	Value
Publication number	US-9395009-B2
Application number	US-201314057621-A
Country	US
Kind code	B2
Filing date	Oct 18, 2013
Priority date	Oct 18, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A fluid flow control device includes a valve body, a valve seat disposed within the valve body, and a valve cage coupled to the valve seat within the valve body. The fluid flow control device also includes a gland defined by the valve body, the valve seat, and the valve cage. The valve body has a first thermal expansion coefficient and the valve seat and/or the valve cage have a second thermal expansion coefficient different from the first thermal expansion coefficient. The fluid flow control device further includes a sealing assembly disposed within the fluid flow control device to provide a seal between the valve body and the valve cage. The sealing assembly exploits differential thermal expansion between the valve body and the valve cage in a direction parallel to the longitudinal axis and in a direction transverse to the longitudinal axis to improve the seal.

First claim

The invention claimed is:

1. A fluid flow control device comprising:
a valve body defining an inlet, an outlet, a fluid flow path extending between the inlet and the outlet, and a longitudinal axis, the valve body having a first thermal expansion coefficient;
a valve seat disposed within the valve body and defining an orifice through which the fluid flow path passes;
a valve cage coupled to the valve seat within the valve body and defining an interior bore, the cage having a second thermal expansion coefficient different than the first thermal expansion coefficient;
a valve plug sized for insertion into the interior bore of the valve cage and movable along an axis between a closed position, in which the valve plug engages the valve seat, and an open position;
a gland defined by at least one of the valve seat and the valve cage; and
a sealing assembly arranged within the gland to provide a seal between the valve body and the valve cage, the sealing assembly comprising a seal portion and a biasing element disposed immediately adjacent the seal portion, and the sealing assembly arranged in a first compression state in which the sealing assembly provides first radial and axial compression forces, the sealing assembly movable to a second compression state in which the sealing assembly provides second radial and axial compression forces greater than the first radial and axial compression forces, the movement of the sealing assembly being due to differential thermal expansion between the valve body and the valve cage in an axial direction that is parallel to the longitudinal axis and in a radial direction that is transverse to the longitudinal axis,
wherein the biasing element comprises a gasket and the seal portion has a thermal expansion coefficient equal to the first or second thermal expansion coefficient, and
wherein the gasket is disposed in contact with the seal portion, the gasket configured to provide the first and second radial compression forces to the seal portion to bias the seal portion outward against the valve body to provide the seal between the valve body and the valve cage.

2. The fluid flow control device of claim 1 , wherein the valve seat and the valve cage are bolted together via a plurality of screws.

3. The fluid flow control device of claim 1 , wherein the valve seat and the valve cage are threaded together.

4. The fluid flow control device of claim 1 , wherein the sealing assembly is arranged within the gland such that a radial gap is formed between the valve cage and the seal portion of the sealing assembly, the radial gap being substantially closed when the sealing assembly moves to the second compression state.

5. The fluid flow control device of claim 1 wherein the seal portion is made of the same material as the valve body.

6. The fluid flow control device of claim 1 wherein the gasket is disposed radially inward of the seal portion within the gland.

7. The fluid flow control device of claim 1 , wherein the gasket comprises a first gasket and the sealing assembly further comprises a second gasket, the first gasket being disposed immediately adjacent the seal portion, and the second gasket being disposed between the valve seat and the valve cage.

8. The fluid flow control device of claim 1 , wherein the sealing assembly further comprises a seal retainer.

9. The fluid flow control device of claim 8 , wherein the seal retainer is positioned between the valve seat and the valve body and immediately adjacent the seal portion and the gasket.

10. The fluid flow control device of claim 1 , wherein the fluid flow control device is configured for operation at a service temperature of between approximately 450 degrees Fahrenheit and approximately 1100 degrees Fahrenheit.

11. The fluid flow control device of claim 1 , wherein the seal portion comprises a first seal portion, the sealing assembly further comprising a second seal portion, a third seal portion, and a fourth seal portion, and wherein the biasing element comprises a first wound gasket, the sealing assembly further comprising a second wound gasket, the first and second seal portions being disposed adjacent the valve body and having a thermal expansion coefficient equal to the first thermal expansion coefficient, the third and fourth seal portions being disposed adjacent the valve cage and having a thermal expansion coefficient equal to the second thermal expansion coefficient, and the first wound gasket being disposed between the first and third seal portions and the second wound gasket disposed between the second and fourth seal portions such that the first wound gasket is configured to provide the first and second radial compression forces to the first and third seal portions to bias the first seal portion toward the valve cage and bias the third seal portion toward the valve body, and the second wound gasket is configured to provide the first and second radial compression forces to the second and fourth seal portions to bias the second seal portion toward the valve cage and bias the fourth seal portion toward the valve body.

12. A fluid flow control device comprising:
a valve body defining an inlet, an outlet, a fluid flow path extending between the inlet and the outlet, and a longitudinal axis, the valve body having a first thermal expansion coefficient;
a valve seat disposed within the valve body and defining an orifice through which the fluid flow path passes;
a valve cage coupled to the valve seat within the valve body and defining an interior bore, the cage having a second thermal expansion coefficient different than the first thermal expansion coefficient;
a valve plug sized for insertion into the interior bore of the valve cage and movable along an axis between a closed position, in which the valve plug engages the valve seat, and an open position;
a gland defined by at least one of the valve seat and the valve cage; and
a sealing assembly arranged within the gland to provide a seal between the valve body and the valve cage, the sealing assembly comprising at least one seal portion and at least one biasing element disposed immediately adjacent the at least one seal portion, and the sealing assembly arranged in a first compression state in which the sealing assembly provides first radial and axial compression forces, the sealing assembly movable to a second compression state in which the sealing assembly provides second radial and axial compression forces greater than the first radial and axial compression forces, the movement of the sealing assembly being due to differential thermal expansion between the valve body and the valve cage in an axial direction that is parallel to the longitudinal axis and in a radial direction that is transverse to the longitudinal axis,
wherein the least one seal portion comprises a first seal portion, a second seal portion, a third seal portion, and a fourth seal portion, and wherein the at least one biasing element comprises first and second wound gaskets, the first and second seal portions being disposed adjacent the valve body and having a thermal expansion coefficient equal to the first thermal expansion coefficient, the third and fourth seal portions being disposed adjacent the valve cage and having a thermal expansion coefficient equal to the second thermal expansion coefficient, and the first wound gasket being disposed between the first and third seal portions and the second wound gasket disposed between the second and fourth seal portions such that the first wound gasket is configured to provide the first and second radial compression forces to the first and third seal portions to bias the first seal portion toward the valve cage and bias the third seal po

Assignees

• Fisher Controls Int

Inventors

• Lovell Michel K

Classifications

• F16K3/265

  with a sleeve sliding in the direction of the flow line · CPC title

• F16K3/32

  Means for additional adjustment of the rate of flow · CPC title

• F16K3/243 Primary

  Packings (F16K3/246 takes precedence) · CPC title

• F16K39/04

  for sliding valves · CPC title

• F16K27/041

  cylindrical slide valves · CPC title