Flow control valve having a seal washer with a secondary sealing surface

Abstract

A flow control valve includes a valve body having a first portion and a second portion attached to the first portion. A flow control member is positioned within the valve body, and a shaft extends through the valve body and is connected to the flow control member to move the flow control member between an open position and a closed position. A sealing gasket is positioned within the valve body and engages the valve body to prevent fluid flow between the first portion and the second portion. The sealing gasket has an annular metal body, a groove, and an insert positioned within the groove. The annular metal body has an inner surface and an opposite outer surface that defines a primary sealing surface. The groove is formed in the outer surface, and the insert defines a secondary sealing surface.

Description

Technical Field

[0001] The present disclosure generally relates to flow control valves, and more particularly, to flow control valves having a metal sealing gasket. Background Art

[0002] Process control systems typically employ flow control valves (such as ball valves, butterfly valves, eccentric disk valves, eccentric plug valves, etc.) to control the flow of process fluids. A flow control valve generally includes a valve internals assembly having a valve seat and a flow control member, the valve seat being disposed in a fluid path and surrounding a flow orifice, and the flow control member (such as a ball, disk, etc.) being disposed in the fluid path. A shaft operatively couples the flow control member to an actuating device to rotate or move the flow control member between an open position and a closed position, thereby selectively allowing or restricting fluid flow between an inlet and an outlet of the flow control valve.

[0003] In some cases, flow control valves may be used in applications (such as high-pressure steam, toxic fluids, fugitive emissions (refining / oil and gas), etc.) and / or are required to pass certification tests (such as Shell MESC 77 / 300, ISO15848-1, API6D Appendix H, etc.), where very low (or no) leakage between individual valves or valve body components is required. However, standard flow control valves typically use metal ring gaskets between the valve or valve body components, which may have problems minimizing leakage caused by thermal expansion / contraction, surface defects, damage / wear, etc. in certain conditions (such as in high-temperature or high-pressure applications). Summary of the Invention

[0004] According to an exemplary aspect of the present invention, a flow control valve includes a valve body having a first portion and a second portion attached to the first portion. A flow control member is positioned within the valve body, and a shaft extends through the valve body and is connected to the flow control member to move the flow control member between an open position and a closed position. A sealing gasket is positioned within the valve body and engages the valve body to prevent fluid flow between the first portion and the second portion. The sealing gasket has: an annular metal body having an inner surface and an opposite outer surface, the outer surface defining a primary sealing surface; a groove formed in the outer surface; and an insert positioned within the groove, the insert defining a secondary sealing surface.

[0005] Further according to any one or more of the foregoing exemplary aspects of the present invention, the flow control valve may further include any one or more of the following preferred forms in any combination.

[0006] In a preferred form, the second part of the valve body is an end adapter.

[0007] In another preferred form, the flow control valve is a ball valve.

[0008] In another preferred form, the secondary sealing surface engages the first part and the second part of the valve body.

[0009] In another preferred form, the insert is graphite.

[0010] In another preferred form, the insert is a graphite laminate.

[0011] In another preferred form, the insert is a polymer.

[0012] In another preferred form, the sealing gasket includes a plurality of grooves formed in the outer surface of the annular metal body, and a plurality of inserts, each insert being positioned within a corresponding one of the plurality of grooves.

[0013] In another preferred form, the outer surface of the sealing gasket includes a first part and a second part that is not parallel to the first part. The grooves are formed in the first part, and second grooves are formed in the second part. Second inserts are positioned in the second grooves to provide a second secondary sealing surface. The secondary sealing surface engages the first part of the valve body, and the second secondary sealing surface engages the second part of the valve body.

[0014] According to another exemplary aspect of the present invention, a sealing gasket for a flow control valve includes an annular metal body having an inner surface and an opposite outer surface, the outer surface defining a primary sealing surface. Grooves are formed in the outer surface, and inserts are positioned within the grooves, the inserts defining a secondary sealing surface.

[0015] Further according to any one or more of the foregoing exemplary aspects of the present invention, the sealing gasket may further include any one or more of the following preferred forms in any combination.

[0016] In a preferred form, the insert is graphite.

[0017] In another preferred form, the insert is a graphite laminate.

[0018] In another preferred form, the insert is a polymer.

[0019] In another preferred form, the sealing washer includes a plurality of grooves formed in the outer surface of the annular metal body, and a plurality of inserts, each insert being positioned in a respective one of the plurality of grooves.

[0020] In another preferred form, the outer surface includes a first portion and a second portion that is not parallel to the first portion. The first groove is formed in the first portion, a second groove is formed in the second portion, and a second insert is positioned in the second groove to provide a second secondary sealing surface.

[0021] In another preferred form, the flow control valve is a ball valve.

[0022] According to another exemplary aspect of the present invention, a sealing washer for a flow control valve includes: an annular metal body having an inner surface and an opposite outer surface, the outer surface defining a primary sealing surface; and means for providing a secondary sealing surface on the outer surface of the annular metal body.

[0023] Further according to any one or more of the foregoing exemplary aspects of the present invention, the sealing washer may further include any one or more of the following preferred forms in any combination.

[0024] In one preferred form, the sealing washer includes means for providing a second secondary sealing surface on the outer surface of the annular metal body.

[0025] In another preferred form, the outer surface of the annular metal body includes a first portion and a second portion that is not parallel to the first portion. The means for providing a secondary sealing surface is positioned on the first portion, and the means for providing a second secondary sealing surface is positioned on the second portion.

[0026] In another preferred form, the means for providing a secondary sealing surface is configured to engage a first portion of the valve body of the control valve, and the means for providing a second secondary sealing surface is configured to engage a second portion of the valve body. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a diagram of an exemplary flow control valve;

[0028] Figure 2 is Figure 1 a diagram of an exemplary sealing washer of the flow control valve;

[0029] Figure 3 is taken along Figure 2 line 3-3 of Figure 2a cross-sectional view of a portion of a sealing gasket;

[0030] Figure 4 yes Figure 1 An enlarged view of a portion of a flow control valve showing the installed Figure 2 Sealing gasket;

[0031] Figure 5 It is available for Figure 1 An illustration of an alternative exemplary sealing gasket in a flow control valve of;

[0032] Figure 6 is along Figure 5 The line 6-6 is intercepted Figure 5 a cross-sectional view of a portion of a sealing gasket; and

[0033] Figure 7 yes Figure 1 An enlarged view of a portion of a flow control valve showing the installed Figure 5 Replacement sealing gasket. DETAILED DESCRIPTION

[0034] The present disclosure relates to a flow control valve having a sealing gasket having one or more inserts having a hardness less than that of a metal body of the sealing gasket, the inserts providing one or more secondary sealing surfaces in addition to the primary sealing surface provided by the outer surface of the metal body. The secondary sealing surface(s) may be used to improve the seal between various valve or valve body components in low leakage requirements or certification testing situations, erosive conditions, or situations where valve or valve body components may be worn, damaged, or defective.

[0035] refer to Figure 1 , an exemplary flow control valve 10, such as a Fisher TMThe Z500 Severe Service Ball Valve typically includes a valve body 15, which includes a first portion 20 (body) defining an inlet 40 and a second portion 25 (end adapter) defining an outlet 45 and attached to the first portion 20 by threaded members 30 and nuts 35. A chamber 50 is formed in the valve body 15 between the inlet 40 and the outlet 45 and a flow control member 55, and the flow control member 55 (which is a ball of the ball valve in the illustrated example) is positioned within and rotatable within the chamber 50 of the valve body 15. An upstream seat 70 is positioned within the chamber 50 between the inlet 40 and the flow control member 55 and is biased by a spring 80 to engage the flow control member 55, thereby preventing fluid leakage between the upstream seat 70 and the flow control member 55. The second portion 25 of the valve body 15 also defines a downstream seat 75, which engages the flow control member 55 near the outlet 45, opposite the upstream seat 70.

[0036] A shaft 65 is connected to the flow control member 55 to move the flow control member 55 between an open position and a closed position, wherein, in the open position, an orifice 60 through the flow control member 55 is aligned or partially aligned with the inlet 40 and the outlet 45 and permits fluid flow through the flow control valve 10, and in the closed position, the orifice 60 is not aligned with the inlet 40 and / or the outlet 45 and does not permit fluid flow through the flow control valve 10. The shaft 65 is also coupled to an actuator (not shown), which provides an actuating force to selectively rotate the flow control member 55, and the shaft 65 extends through the first portion 20 of the valve body 15, wherein a packing 95 is positioned between the shaft 65 and the valve body 15 to prevent fluid leakage between the shaft 65 and the valve body 15. The packing 95 is compressed and held in place by a gland plate 85, which is fixed to the first portion 20 of the valve body 15 by threaded members 90 and nuts 92. A thrust washer 97 may also be positioned between the first portion 20 of the valve body 15 and a flange 67 of the shaft 65 to bias the shaft 65 toward the flow control member 55.

[0037] A seal washer 100 ( Figures 2 - 4 ) or 200 ( Figures 5 - 7 ) is positioned within the chamber 50 of the valve body 15 and engages the first portion 20 and the second portion 25 of the valve body 15 to prevent fluid flow and leakage between the first portion 20 and the second portion 25. Although the seal washers 100, 200 are shown herein engaging two components of the valve body and preventing leakage and fluid flow between the two components of the valve body, the seal washers 100, 200 may be used anywhere in the flow control valve 10 to prevent leakage and fluid flow between any two metal components or at the junction between any two metal components.

[0038] Reference Figures 2 - 4 , the first exemplary seal washer 100 has an annular metal body 105 having an inner surface 110, an opposite outer surface 115, and side surfaces 120 interconnecting the inner surface 110 and the outer surface 115. In the example shown, the outer surface 115 has first, second, and third portions 125, 130, 135 and defines a primary sealing surface 140 that engages the first portion 20 and the second portion 25 of the valve body 15 and provides a metal-to-metal seal to prevent or minimize leakage or fluid flow between the first portion 20 and the second portion 25. Alternatively, the annular metal body 105 may have any desired cross-sectional shape suitable for a particular application rather than having the generally trapezoidal shape shown in Figures 2 - 4 . A groove 145 is formed in the outer surface 115, specifically in the third portion 135 in the example shown, and an insert 150 is positioned within the groove 145. The outer surface 155 of the insert 150 defines a secondary sealing surface 160 that also engages the first portion 20 and the second portion 25 of the valve body 15 to assist the metal-to-metal seal of the primary sealing surface 140 to prevent or mitigate leakage or fluid flow between the first portion 20 and the second portion 25. The insert 150 may be made of solid graphite, graphite composite, or graphite laminate (e.g., graphite with metal reinforcement) and has an uncompressed radial length L1 that is slightly greater than the radial length L2 of the groove 145 such that when the seal washer 100 is initially assembled and the insert 150 is compressed, the outer surface 155 of the insert 150 radially outwardly offsets from the outer surface 115 of the body 105 ( Figure 3 ), and when the seal washer 100 is installed in the flow control valve 10, the outer surface 155 is coplanar with the outer surface 115 of the valve body 105 ( Figure 4 ). Using graphite, graphite composite, or graphite laminate for the insert 150 enables the insert 150 to rebound with changes in the outer surface 155 (e.g., thermal changes, physical changes, etc.) and can provide a more effective seal with the first portion 20 and the second portion 25 of the valve body 15 compared to a metal-to-metal seal of the outer surface 115 of the body 105 against a defective surface (e.g., scratches, dents, oxidation, etc.). Alternatively, if the flow control valve 10 is used in a low-temperature application, the insert 150 may also be made of a polymer such as an elastomer.

[0039] Reference Figures 5 - 7, the second exemplary seal washer 200 has an annular metal body 205 having an inner surface 210, an opposite outer surface 215, and a side surface 220 interconnecting the inner surface 210 and the outer surface 215. In the illustrated example, the outer surface 215 has first, second, and third portions 225, 230, 235 and defines a primary seal surface 240 that engages the first portion 20 and the second portion 25 of the valve body 15 and provides a metal-to-metal seal to prevent or minimize leakage or fluid flow between the first portion 20 and the second portion 25. Alternatively, the annular metal body 205 may have any desired cross-sectional shape suitable for a particular application rather than having the substantially trapezoidal shape shown in Figures 5 - 7 the example above. A groove 245 is formed in the outer surface 215, specifically in the first portion 225 in the illustrated example, and an insert 250 is positioned within the groove 245. The outer surface 255 of the insert 250 defines a secondary seal surface 260 that engages the first portion 20 of the valve body 15 to assist the metal-to-metal seal of the primary seal surface 240 to prevent or mitigate leakage or fluid flow between the first portion 20 and the second portion 25. A second groove 265 is also formed in the outer surface 215, specifically in the second portion 230 in the illustrated example, and a second insert 270 is positioned within the second groove 265. The outer surface 275 of the second insert 270 defines a second secondary seal surface 280 that engages the second portion 25 of the valve body 15 to assist the metal-to-metal seal of the primary seal surface 240 to prevent or mitigate leakage or fluid flow between the first portion and the second portion 25. Although two grooves 245, 265 and two inserts 250, 270 are shown in the above example, any number of grooves and inserts may be used, which are suitable for a particular application, to provide any number of desired secondary seal surfaces.

[0040] The inserts 250, 270 may be made of solid graphite, graphite composite, or graphite laminate (e.g., graphite with metal reinforcement) and have an uncompressed radial length L3 that is slightly greater than the radial length L4 of the groove 245 and the second groove 265 such that when the seal washer 200 is initially assembled and the inserts 250, 270 are compressed, the outer surfaces 255, 275 of the inserts 250, 270 radially outwardly offset from the outer surface 215 of the body 205 ( Figure 3 ), and when the seal washer 200 is installed in the flow control valve 10, the outer surfaces 255, 275 are coplanar with the outer surface 215 of the body 205 ( Figure 7)。Using graphite, graphite composites, or graphite laminates for inserts 250, 270 enables inserts 250, 270 to be capable of rebounding with changes in the outer surfaces 255, 275a (e.g., thermal changes, physical changes, etc.), and can provide a more effective seal with the first part 20 and the second part 25 of the valve body 15 compared to a metal-to-metal seal of the outer surface 215 of the body 205 against a defective surface (e.g., scratches, dents, oxidation, etc.). Alternatively, if the flow control valve 10 is used in a cryogenic application, inserts 250, 270 can also be made of a polymer such as an elastomer.

[0041] Although various embodiments have been described above, the present disclosure is not intended to be limited thereto. Changes may be made to the disclosed embodiments that are still within the scope of the appended claims.

Claims

1. A flow control valve, comprising: a valve body having a first part and a second part attached to the first part; a flow control member positioned within the valve body; a shaft extending through the valve body and connected to the flow control member to move the flow control member between an open position and a closed position; and a sealing gasket positioned within the valve body and engaging the valve body to prevent fluid flow between the first part and the second part, the sealing gasket comprising: an annular metal body having an inner surface and an opposite outer surface, the outer surface defining a primary sealing surface that provides a metal-to-metal seal to prevent fluid flow between the outer surface and the valve body; a groove formed in the outer surface; and an insert positioned within the groove, the insert defining a secondary sealing surface positioned on the insert to engage the first part and the second part of the valve body.

2. The flow control valve according to claim 1, wherein the second part of the valve body is an end adapter.

3. The flow control valve according to claim 1, wherein the flow control valve is a ball valve.

4. The flow control valve according to claim 1, wherein the insert is graphite.

5. The flow control valve according to claim 1, wherein the insert is a graphite laminate.

6. The flow control valve according to claim 1, wherein the insert is a polymer.

7. The flow control valve according to claim 1, comprising: a plurality of grooves formed in the outer surface of the annular metal body, and a plurality of inserts, each insert being positioned within a respective one of the plurality of grooves.

8. A sealing gasket for a flow control valve, comprising: an annular metal body having an inner surface and an opposite outer surface, the outer surface defining a primary sealing surface and including a first part and a second part not parallel to the first part; a groove formed in the outer surface, between the first part and the second part; and an insert positioned within the groove, between the first part and the second part, the insert defining a secondary sealing surface positioned on the insert to engage a first part and a second part of the valve body.

9. The sealing gasket according to claim 8, wherein the insert is graphite.

10. The sealing gasket according to claim 8, wherein the insert is a graphite laminate.

11. The sealing gasket according to claim 8, wherein the insert is a polymer.

12. The sealing gasket according to claim 8, comprising: a plurality of grooves formed in the outer surface of the annular metal body, and a plurality of inserts, each insert being positioned within a respective one of the plurality of grooves.

13. The sealing gasket according to claim 8, wherein the flow control valve is a ball valve.

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