Shut-off seal for high temperature pressure balanced valve and related method

Abstract

Disclosed are closing seals for high temperature pressure balanced valves and related methods. A valve assembly includes a valve body having a seat retainer chamber and a floating seat ring disposed with an inner sidewall adjacent the seat retainer chamber. The floating seat ring is configured to contact a first portion of a plug during a closing stroke of the plug at a single annular location before a second portion of the plug contacts a valve main seat. A static seal is positioned radially between the floating seat ring and the inner sidewall of the seat retainer chamber.

Description

[0001] This invention is a divisional application, with its parent application number being 201780046865.3, the application date being July 27, 2017, and the invention title being "A closing seal for a high-temperature pressure balancing valve and a related method".

[0002] Priority requirements

[0003] This application claims the benefit of U.S. Patent Application Serial No. 62 / 368,033, filed on July 28, 2016, entitled “Closed Seal and Related Method for High Temperature Pressure Balancing Valve”. Technical Field

[0004] This invention generally relates to pressure balancing control valves used in high-temperature services. More specifically, embodiments of the invention relate to pressure balancing control valves that include a shut-off sealing system when the valve is in the closed position. Background Technology

[0005] Pressure-balanced (PB) control valves require a dynamic seal between a PB plug and a sleeve in which the plug slides up and down. In a PB control valve, the pressure contained at the top of the plug is almost equal to the pressure at the bottom of the plug, which is typically achieved through an orifice passing through the plug. This "balancing" effect on the plug allows the plug to pass through a high valve pressure drop with minimal actuator load. This balancing effect reduces the overall cost of the valve because a smaller actuator can be used to control the flow through the valve.

[0006] Dynamic seals are typically used to seal between the plug and sleeve to maintain pressure in the chamber at the top of the plug. The dynamic seal is usually located on the outer diameter of the plug and can be a carbon or metal piston ring seal for high-temperature applications. Some high-temperature applications require a very low leakage level that meets ANSI / FCI 70-2 Class V leakage rate when the valve is closed. High-temperature dynamic seals typically only provide ANSI / FCI 70-2 Class III or Class IV closure. At high-temperature applications (+500℉), fluid from the chamber above the plug will bypass the dynamic seal to a degree that would prevent the valve from achieving ANSI / FCI 70-2 Class V closure without pilot-operated plug designs. Pilot-operated plug designs involve more components, introduce stability limitations, and are also more expensive. Summary of the Invention

[0007] This invention is provided to introduce some concepts in a simplified form. These concepts are described in more detail in the following detailed description of the disclosed embodiments. This invention is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0008] In some embodiments, the valve assembly includes a valve body having a seat retainer chamber and a seat ring disposed adjacent to the inner sidewall of the seat retainer chamber. The main seat ring is configured to contact a first portion of the plug at a single annular position during the plug's closing stroke before a second portion of the plug contacts the floating valve seat. The valve assembly includes a static seal radially located between the seat ring and the inner sidewall of the seat retainer chamber.

[0009] In another embodiment, a method of forming a valve assembly includes forming a valve body including an inlet, an outlet, and a seat retainer chamber. The method includes positioning a floating seat ring adjacent to an inner wall of the seat retainer chamber, radially positioning a static seal between the seat ring and the inner wall of the seat retainer chamber, and positioning a plug within the seat retainer chamber. The plug includes a plug head having a first portion and a second portion. The first portion of the plug head is configured to contact the main seat ring at a single annular position during the closing stroke of the plug before the second portion of the plug head contacts the floating valve seat. Attached Figure Description

[0010] Figure 1 A cross-sectional front view of a valve body subassembly according to an embodiment of the present disclosure is shown.

[0011] Figure 2 It shows Figure 1 An enlarged cross-sectional front view of the valve body subassembly's closing sealing assembly.

[0012] Figure 3 It shows Figure 2 A further enlarged cross-sectional front view of the contact point between the plug head and the floating seat ring shown. Detailed Implementation

[0013] In some cases, the illustrations presented herein are not actual views of any particular valve, plug, seat, or seal, but merely idealized representations used to describe embodiments of this disclosure. Additionally, common elements across the figures may retain the same numerical names.

[0014] Various embodiments of this disclosure relate to embodiments of a pressure balancing control valve, which includes a shut-off sealing system comprising at least one static seal and at least one dynamic seal. Reference Figure 1 A cross-sectional front view of a valve assembly 2 according to at least one embodiment is shown. The valve body subassembly 2 may include a valve body 4 having an inlet 6, an outlet 8, and a seat retainer chamber 10. It should be understood that the inlet 6 can also be used as an outlet, and the outlet 6 can also be used as an inlet, because the pressure-balanced control valve of this disclosure is a bidirectional, closable seal. A plug 12 may be positioned in the seat retainer chamber 10 and configured to move within the seat retainer chamber 10. Figure 1In the diagram, plug 12 is shown in the closed position (i.e., no fluid flows through the valve). Plug 12 may include a plug head 14 that fills a portion of the seat retainer chamber 10. Valve body subassembly 2 may include a pressure balancing valve. Therefore, plug head 14 may include a plurality of pressure balancing orifices 15 that extend through the plug head and allow fluid to balance the pressure on plug head 14, thereby reducing the magnitude of the force applied by the actuator to open and close the valve.

[0015] In at least some embodiments, the plug 14 may include an annular flange 16 configured adjacent to the inner sidewall of the seat retainer chamber 10. Figure 1 In the illustrated embodiment, the seat retainer chamber 10 may be defined by a pressure equalization (PB) sleeve 18, a seat retainer 20, a main seat ring 22, and a floating seat ring 24. The PB sleeve 18 and the seat retainer 20 may form at least a portion of the inner sidewall of the seat retainer chamber 10. As discussed in more detail below, the floating seat ring 24 may be held between the PB sleeve 18 and the seat retainer 20. The floating seat ring 24 may be located within the seat retainer chamber 10 such that the plug 14 contacts the floating seat ring 24 at least substantially only when the plug 12 is in the closed position (i.e., when the plug 12 is adjacent to the main seat ring 22 or when the plug 12 is on the main seat ring 22). The plug 14 may include a dynamic seal 26, which may also be referred to as a PB seal or PB sealing ring. The dynamic seal 26 may be positioned on the outer diameter of the plug 14 to be adjacent to the inner wall 27 of the PB sleeve 18. The dynamic seal 26 helps seal the fluid passage between the plug or sleeve chamber 28 of the seat retainer chamber 10 located above the plug head 14 and the plug head 14 and PB sleeve 18. In at least some embodiments, the dynamic seal 26 may be positioned in a groove located in a portion of the annular flange 16. As a non-limiting example, the dynamic seal 26 may be a carbon or metal piston ring seal. The dynamic seal only needs to maintain balanced pressure when the plug is moving and not on the master seat ring.

[0016] The static seal 30 (also known as the PB closing seal) can be positioned within a portion of the inner wall of the seat retainer chamber 10 located between the floating seat ring 24, the PB sleeve 18, and the seat retainer 20. Now refer to... Figure 2The floating seat ring 24 can be held between the PB sleeve 18 and the seat retainer 20. The bottom portion 32 of the PB sleeve 18 may include a shoulder 34 adjacent to an annular recessed surface 36 formed in the PB sleeve 18. The shoulder 34 of the lower portion 32 of the PB sleeve 18 may be positioned adjacent to the top surface 38 of the floating seat ring 34. The annular recessed surface 36 of the bottom portion 32 of the PB sleeve 18 may be positioned adjacent to the radially outer surface 40 of the floating seat ring 34. The floating seat ring 24 may include an annular longitudinal extension 42 extending downward from the bottom surface 44 of the floating seat ring 24. In this way, when viewed in a plane extending along the longitudinal axis of the floating seat ring 24, the cross-section of the floating seat ring 24 may have an inverted L-shape. The bottom surface 46 of the PB sleeve 18 may abut against the upper surface 48 of the seat retainer 20. The upper portion of the seat retainer 20 may include an upwardly depending flange forming a raised platform surface 52. An annular platform 54 can be formed in the radially inward portion of the raised platform surface 52, the annular platform 54 being configured to receive a portion of the annular longitudinal extension 42 of the floating seat ring 24. A static seal 30 can be located in an annular cavity radially positioned between the longitudinal extension 42 of the floating seat ring 24 and the annular recessed surface 36 of the PB sleeve 18, and longitudinally positioned between the shoulder 38 of the PB sleeve 18 and the raised platform surface 52 of the seat retainer 20.

[0017] The static seal 30 may include an annular sealing spring 58 disposed within a C-shaped annular sealing sleeve 60. The annular sealing spring 58 may independently power the static seal 30. As a non-limiting example, the annular sealing spring 58 may be a helical spring, such as a single-coil or double-coil helical spring. The annular sealing spring 58 may include one or more high-strength materials, including, as non-limiting examples, nickel, elgiloy nonmagnetic alloys, and Inconel. TM And Incoloy. The C-shaped annular sealing sleeve 60 may include one or more materials, including, as non-limiting examples, silver, nickel, Incoloy and Monel.

[0018] The upper and radially inward portions of the floating seat ring 24 may include an inclined surface 62 adjacent to the top surface 38 of the floating seat ring 24. The plug head 14 may include a radially outwardly inclined surface 64, sized and oriented to contact the floating seat ring 24 during the closing stroke of the plug 12. Figure 2 and 3In the cross-sectional view, the floating seat ring 24 and the plug head 14 can be cooperatively configured such that during the closing stroke of the plug head 14, the outer inclined surface 64 of the plug head 14 contacts the floating seat ring 24 at a single contact point 66 located at the lower edge of the inclined surface 62 of the floating seat ring 24. It should be understood that, in three-dimensional space, the single contact point 66 extends circumferentially around the lower edge of the inclined surface 62 of the floating seat ring 24. Figure 2 In the diagram, the plug 14 is shown in a closed (i.e., downward) stroke position in the axial position, in which the outer surface 64 of the plug 14 first contacts the floating seat ring 24 at its single contact point 66. Therefore, Figure 2 The annular sealing spring 58 and C-shaped annular sealing sleeve 60 of the static seal 30 in an uncompressed state are depicted. During the closing stroke of the plug 14, when the plug 14 is separated from the main seat ring 22 by a distance of approximately 0.010 inches (by way of a non-limiting example), the outer surface 64 of the plug 14 may initially contact a single contact point 66 of the floating seat ring 24. In a particular embodiment, when the plug first contacts the floating seat ring, it will be compressed between 0.005 and 0.010 inches before it contacts the main seat ring. It can continue to compress the floating seat ring, depending on the deflection occurring in the main seat ring. This is typically only a few thousand inches more. As described in more detail below, the static seal 30 can be compressed as the stroke of the plug 14 further penetrates into the main seat ring 22.

[0019] like Figure 3 As shown more clearly in the diagram, the inclined surface 62 of the floating seat ring 24 and the outer surface 64 of the plug 14 can be oriented relative to each other at an angle α ranging from about 1.5 degrees to about 20 degrees. In certain embodiments, the angle α can be about 3 degrees, plus or minus 1 degree. For example, in some embodiments, the angle α between the inclined surface 62 of the floating seat ring 24 and the outer surface 64 of the plug 14 can be about 3 degrees. In such embodiments, the closing stroke of the plug 14 (i.e., when the valve assembly as...) Figure 1 and Figure 2 As shown in the positioning diagram, the floating seat ring 24 can be moved downwards (in the downward direction) in a substantially axial direction only, with substantially no radial movement to compress the static seal 30. In this way, the floating seat ring 24 can be sealed by means of a static line-load contact point, which forms a more robust seal than a seal utilizing a sliding surface. For example, since the plug 14 and the floating seat ring 24 have no surfaces that slide against each other, particles of "dirty" fluid or metal oxides present in the fluid due to corrosion can significantly less interfere in the valve assembly 2 disclosed herein. In addition, the lack of a sliding surface also prevents friction between the plug 14 and the floating seat ring 24, thereby avoiding the instability of sudden release of friction (also known as "stick slip") during the initial stroke when the plug 14 retracts from the floating seat ring 24.

[0020] In response to the closing stroke of the plug 14, the downward axial movement of the floating seat ring 24 can compress the annular sealing spring 58 of the static seal 30 and the C-shaped annular sealing sleeve 60 to form a flow-tight seal between the sealing sleeve 60, the bottom surface 44 of the floating seat ring 24, and the raised platform surface 50 of the seat retainer 20. Therefore, Figure 2 The orientation of the opening of the C-shaped annular sealing sleeve shown provides a seal in both directions between the portion 28 of the seat retainer chamber 10 above the plug head 14 and the valve outlet 8. This is also true when the flow alternates in opposite directions. The actuator of the drive plug 12 can be sized to have sufficient force to compress the static seal 30 after the outer surface 64 of the plug head 14 contacts the inclined surface 62 of the floating seat ring 24. In embodiments where the annular sealing spring 58 is a helical spring, the helical spring 58 can fully recover without loosening or deforming even after repeated compression, unlike wedge seals used in the art.

[0021] It should be understood that the static seal 30 can be constrained by the adjacent portions of the floating seat ring 24, PB sleeve 18, and seat retainer 20 to prevent the static seal 30 from "bursting" when the plug 14 is pulled open under high pressure. Additionally, the position of the static seal 30 within the cavity between the adjacent portions of the floating seat ring 24, PB sleeve 18, and seat retainer 20 protects the static seal 30 from the damaging effects of the fluid flowing through the valve.

[0022] Another embodiment of the invention includes a method of manufacturing a valve assembly. This method may include forming a valve body including an inlet, an outlet, and a seat retainer chamber. A dynamic seal may be positioned in an annular groove located in the outer diameter of an annular flange of a plug. A static seal may be positioned between a longitudinal extension of a floating seat ring, a bottom surface of the floating seat ring, an inner surface of a pressure balancing sleeve, and an upper surface of the seat retainer. The outer surface of the plug may be oriented relative to the inner surface of the floating seat ring such that the plug contacts the floating seat ring at a single point of contact during the plug's closing stroke.

[0023] The valve assembly 2 for a PB control valve, as disclosed herein, offers the advantage of providing tight closure in high-temperature applications exceeding 500℉ without pilot-operated components (which also require ANSI / FCI 70-2 Class V closure), because pilot-operated valves have additional components that typically lead to stability limitations and are generally more expensive than non-pilot-operated valves. Furthermore, even when the plug 14 engages with the main seat ring 22, the dynamic seal 26 can only provide Class III or Class IV closure, but Class V closure can be provided through the configuration of the plug 14, floating seat ring 24, PB sleeve 20, and seat retainer 20 disclosed herein. In this way, any leakage from the portion 28 of the seat retainer chamber above the plug 14, which bypasses the dynamic seal 26, when the plug contacts the main seat ring 22 can be sealed to the valve outlet 8 by the static seal 30.

[0024] While certain embodiments have been described and illustrated in the accompanying drawings, these embodiments are merely illustrative and not intended to limit the scope of the invention. Furthermore, this disclosure is not limited to the specific structures and arrangements shown and described, as various other additions, modifications, and deletions to the described embodiments will be apparent to those skilled in the art. Therefore, the scope of this disclosure is limited only by the literal language of the appended claims and their equivalents.

Claims

1. A valve assembly, comprising: Valve body, which includes a seat retainer chamber; A floating seat ring, disposed in the seat retainer chamber, is configured to contact the first portion of the plug at a single annular position before the second portion of the plug contacts the valve seat during the closing stroke of the plug; A sleeve that at least partially defines the inner wall of the seat retainer chamber; A static seal, radially positioned between the floating seat ring and the inner sidewall defined by the sleeve; and A seat retainer that holds the floating seat ring in the seat retainer chamber, wherein the static seal is axially positioned between the floating seat ring and the seat retainer.

2. The valve assembly according to claim 1, wherein, The floating seat ring includes an annular extension that extends axially along the static seal.

3. The valve assembly according to claim 2, wherein, The annular extension of the floating seat ring surrounds the static seal in a cavity defined between the sleeve, the seat retainer, and the floating seat ring.

4. The valve assembly according to claim 2, wherein, The annular extension of the floating seat ring overlaps with at least a portion of the seat retainer in the radial direction.

5. The valve assembly according to claim 3, wherein, The floating seat ring is held between the sleeve and the seat retainer.

6. The valve assembly according to claim 1, wherein, The static seal is disposed in a cavity that is radially positioned between the axial extension of the floating seat ring and the sleeve, and longitudinally positioned between the floating seat ring and the seat retainer.

7. The valve assembly according to claim 1, wherein, The static seal includes a helical spring.

8. A sealing assembly for use with a valve assembly, the sealing assembly comprising: A floating seat ring, including an annular extension, is configured to be disposed in and movable within a seat retainer chamber of a valve assembly, the floating seat ring being configured to contact a first portion of the plug at a single annular position during the closing stroke of the plug of the valve assembly before a second portion of the plug contacts the valve seat; A seat retainer configured to retain the floating seat ring within the seat retainer chamber; as well as A static seal is arranged radially adjacent to the annular extension of the floating seat ring and axially between the body portion of the floating seat ring and the seat retainer.

9. The sealing assembly of claim 8, further comprising a sleeve configured to at least partially surround the floating seat ring in the radial direction and define an inner wall in the seat retainer chamber.

10. The sealing assembly according to claim 9, wherein, The static seal is contained within a cavity defined by the floating seat ring, the seat retainer, and the sleeve.

11. The sealing assembly according to claim 10, wherein, The annular extension of the floating seat ring overlaps with at least a portion of the seat retainer along the radial direction of the sealing assembly.

12. The sealing assembly according to claim 11, wherein, The seat retainer includes an annular notch configured to receive a portion of the annular extension of the floating seat ring.

13. The sealing assembly according to claim 10, wherein, The static seal is contained in a cavity defined between the floating seat ring and the seat retainer.

14. The sealing assembly according to claim 10, wherein, The floating seat ring is configured to move substantially only in the axial direction after being contacted by the stopper during the closing stroke of the stopper.

15. A method of forming a seal in a valve assembly, comprising: A movable floating seat ring is provided in the seat retainer chamber of the valve assembly; During the closing stroke of the plug of the valve assembly, the first portion of the plug contacts the floating seat ring at a single annular position before the second portion of the plug contacts the valve seat; The floating seat ring is held in the seat retainer chamber by a seat retainer; and During the closing stroke of the plug, the static seal is compressed by the floating seat ring, which is axially positioned between the floating seat ring and the seat retainer.

16. The method of claim 15, further comprising: The static seal is radially surrounded by the annular extension of the floating seat ring.

17. The method of claim 16, further comprising: A portion of the annular extension of the floating seat ring is radially overlapped along the seat retainer.

18. The method of claim 15, further comprising: The static seal and the floating seat ring are radially surrounded by a sleeve.

19. The method of claim 18, further comprising: The static seal is surrounded by the floating seat ring, the seat retainer, and the sleeve.

20. The method of claim 16, further comprising: While at least a portion of the static seal remains fixed in the axial direction, the floating seat ring is moved in the axial direction.

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