Patent Application
20180087675
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Ball valves are employed to open or close to enable or block a flow of fluid in a variety of applications. Typical ball valves may include a body, an adapter, a rotatable ball disposed within a body cavity defined between the body and the adapter, and a stem coupled to the ball. However, when the ball rotates to a closed position to block the flow of fluid, some of the fluid may become trapped in the body cavity of the ball valve. The pressure of the trapped fluid within the body cavity may increase, such as due to temperature variations, for example. If not vented, the pressure may adversely affect surrounding parts, result in leakage or release of the fluid to the atmosphere, and/or increase torque needed to move the ball toward the open position.
Various features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:
One or more specific embodiments of the present invention will be described below. These described embodiments are only exemplary of the present invention. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
The disclosed embodiments relate generally to self-relieving seat assemblies for use within a floating ball valve. The seat assemblies may be positioned between a ball and a housing of the ball valve, and the seat assemblies may be annular seat assemblies having a seat body and a seal that supports a biasing member. During operation of the ball valve, the seat assemblies and the ball are configured to move (e.g., float) relative to the housing of the ball valve in response to a pressure differential between a cavity located between an upstream seat assembly and a downstream seat assembly, a bore upstream of the ball, and/or a bore downstream of the ball. As discussed in more detail below, when the ball valve is in a closed position, the seat assemblies may move relative to the housing and/or relative to the ball to relieve pressure (e.g., pressure within the cavity), while blocking fluid flow across the ball valve (e.g., between the bore upstream of the ball and the bore downstream of the ball). In the disclosed embodiments, the seat body and the seal may be physically separate structures, which may enable use of different materials for these components, thereby improving the sealing capabilities and/or the overall life cycle of the seat assemblies, for example. Furthermore, such a configuration may facilitate manufacturing of the seat assemblies, maintenance operations, and/or repair operations, for example.
Turning now to the figures,
In the closed position 24, the ball 16 blocks fluid flow through the ball valve 10. As shown, in the closed position 24, a bore 30 of the ball 16 is generally perpendicular to an upstream bore 32 defined by the upstream housing 12 and a downstream bore 34 defined by the downstream housing 14, such that fluid is blocked from flowing through the ball valve 10 (e.g., from the upstream bore 32 to the downstream bore 34). In an open position, the bore 30 of the ball 16 is aligned with the bores 32, 34 to enable fluid flow through the ball valve 10. Thus, when the ball valve 10 is in the open position, a fluid 36 may enter through the upstream housing 12 and exit through the downstream housing 14. As used herein, the terms upstream and downstream are defined with respect to a flow path of the fluid 36. For example, in the illustrated embodiment, the upstream housing 12 is upstream from the downstream housing 14 of the ball valve 10, because the fluid 36 flows from the upstream housing 12 toward the downstream housing 14. It should be understood that in certain embodiments the flow path of the fluid 36 may be in an opposite direction such that the structural features of the upstream housing 12 and the downstream housing 14 are exchanged (e.g., the fluid 36 flows from an adapter to a body of the housing 11).
As illustrated in
During operation of the ball valve 10, the seat assemblies 38, 40 may create respective seals between the ball 16 and the upstream housing 12 and between the ball 16 and the downstream housing 14. The seat assemblies 38, 40 may be configured to move (e.g., axially) relative to the housing 11 and/or the ball 16 and may enable the ball 16 to move (e.g., axially) relative to the housing 11 in response to pressure differentials across various components within the ball valve 10. As discussed in more detail below, such a configuration may enable the seat assemblies 38, 40 to automatically relieve pressure within a cavity 60 defined by the housing 11 and located between the seat assemblies 38, 40.
In some embodiments, when the ball 16 of the ball valve 10 moves from the open position to the closed position 24, fluid may be trapped within the cavity 60 of the ball valve 10, and a cavity pressure, Pcavity, may be approximately the same as an upstream pressure, Pupstream, for at least some period of time after reaching the closed position 24. In certain embodiments, a downstream pressure, Pdownstream, within the downstream housing 14 is relieved or released after the ball valve 10 is moved from an open position to the closed position 24. Thus, in the closed positioned 24, the upstream pressure, Pupstream, exceeds the downstream pressure, Pdownstream, and the ball 16 and the downstream seat assembly 40 may be driven to move in an axial direction 62 relative to the housing 11 and may form a seal (e.g., annular seal) between the ball 16 and the downstream housing 14 that blocks fluid flow across the ball valve 10.
As discussed in more detail below, the seat assemblies 38, 40 may include features that enable the ball valve to self-relieve (e.g., automatically relieve) the cavity pressure, Pcavity, while blocking fluid flow across the ball valve 10 from the upstream bore 32 of the upstream housing 12 to the downstream bore 34 of the downstream housing 14. For example, while the ball valve 10 is in the closed position 24, if the cavity pressure, Pcavity, exceeds a threshold pressure (e.g., the upstream pressure, Pupstream), the cavity pressure, Pcavity, may drive the upstream seat assembly 38 axially relative to the ball 16 and the upstream housing 12, thereby causing the upstream seat assembly 38 to separate from the ball 16 and enabling the cavity pressure, Pcavity, to release into the upstream bore 32 of the upstream housing 12. While the cavity pressure, Pcavity, is released into the upstream bore 32, the downstream seat assembly 40 may maintain the seal between the ball 16 and the downstream housing 14 to block fluid flow across the ball valve 10. To facilitate discussion, the ball valve 10 and the components therein may be described with reference to the axial axis or direction 62, a radial axis or direction 66, and/or a circumferential axis or direction 68.
With the foregoing in mind,
As shown, the body 42 includes a ball-contacting surface 70 (e.g., annular surface) configured to directly contact the ball 16 of the ball valve 10 and a seal-receiving groove 72 (e.g., annular groove) configured to receive and/or to support the seal 44. The seal 44 may have a grooved annular wall 43, which has a c-shaped, u-shaped, or v-shaped cross-section 45 extending circumferentially 68 about a central axis 95. The grooved annular wall 43 may include a first radially-extending arm 74 (e.g., annular arm or portion) and a second radially-extending arm 76 (e.g., annular arm or portion), which may be joined together at respective radially-inner portions and/or by a bend 78 (e.g., annular bend or bend portion) at a radially-inner portion 80 of the seal 44. In the undeformed position 71, the radially-extending arms 74, 76 may be generally parallel to one another or angled in a first direction or at a first angle along the central axis 95 of the seal 44. In the illustrated embodiment, the first radially-extending arm 74 is configured to directly contact the body 42, and the second radially-extending arm 76 is configured to directly contact the upstream housing 12 when the upstream seat assembly 38 is assembled within the ball valve 10. Thus, in operation, the upstream seat assembly 38 may extend axially between and form a seal between the body 42 and the upstream housing 12.
As shown, the biasing member 46 is a cantilever spring having a grooved annular wall 47, which has a c-shaped, u-shaped, or v-shaped cross-section 49 extending circumferentially 68 about the central axis 95 and is positioned within a cavity 82 (e.g., annular cavity) defined between the first radially-extending arm 74 and the second radially-extending arm 76 of the seal 44. The grooved annular wall 47 of the biasing member 46 may include a first radially-extending arm 81 (e.g., annular arm or portion) and a second radially-extending arm 83 (e.g., annular arm or portion), which may be joined together at respective radially-inner portions and/or by a bend 87 (e.g., annular bend or bend portion) at a radially-inner portion 89 of the biasing member 46. In the undeformed position 71, the radially-extending arms 81, 83 may be generally parallel to one another or angled in a first direction or at a first angle along the central axis 95 of the seal 44. The biasing member 46 may be held in place within the cavity 82 via protrusions 91, 93 (e.g., inwardly extending annular protrusions) at the respective radially-outer ends of the radially-extending arms 74, 76 of the seal 44. As shown, the radially-inner portion 89 of the biasing member 46 may directly contact and may be supported by an annular surface 84 of the radially-inner portion 80 of the seal 44. The biasing member 46 may be formed from any suitable material, such as metal or metal alloy material, a plastic or polymeric material, or a composite material, for example. In some embodiments, the biasing member 46 is formed from a material that is different from a respective material of the body 42 and/or the seal 44.
The biasing member 46 may be configured to resist axial compression and may bias the first radially-extending arm 74 and the second radially-extending arm 76 of the seal 44 away from one another along the axial axis 62. As shown, in the undeformed position 71, respective radially-outer ends of the first radially-extending arm 74 and the second radially-extending arm 76 are separated by an initial distance 86 (e.g., a first distance). In the illustrated embodiment, the seal 44 is a one-piece structure and may be formed from a single material, and together the seal 44 and the biasing member 46 form a seal assembly 85 that is configured to form an annular seal between the body 42 and the upstream housing 12 without additional components in the seal assembly 85 and/or without other components or structures positioned in the groove 72 between the body 42 and the upstream housing 12. Similarly, in certain embodiments, the body 42 may be a one-piece structure and/or may be formed from a single material. The body 42 may have any suitable configuration or geometry, including an alternative cross-sectional shape shown in
As shown in
As shown, the body 42 includes the first axially-facing surface 102, a second axially-facing surface 108 (e.g., annular surface, axially downstream surface), a radially-inner surface 110 (e.g., annular surface), and a radially-outer surface 112 (e.g., annular surface). As shown, the ball-contacting surface 70 is a tapered or angled surface (e.g., relative to the axial axis 62) and extends generally between the radially-inner surface 110 and the second-axially facing surface 108. As shown, in certain embodiments, the ball-contacting surface 70 includes a first portion 114 proximate to the radially-inner surface 110 and that is configured to seal against the ball 16, and the first portion 114 is joined to a second portion 116 of the ball-contacting surface 70 via a radially-extending portion 118. Such a configuration may limit the contact surface area between the ball-contacting surface 70 and the ball 16, which in turn may increase a contact pressure between the body 42 and the ball 16 and form a more effective annular seal between the body 42 and the ball 16. In certain embodiments, the body 42 includes a tapered or angled surface 120 (e.g., beveled edge, annular surface) that extends from the radially-inner surface 110 and the first axially-facing surface 102. As shown, the body 42 is positioned within a recess 113 (e.g., annular recess) of the upstream housing 12.
In the illustrated embodiment, the seal 44 is positioned within the seal groove 72 of the body 42 and is configured to form a seal (e.g., annular seal) between the body 42 and the upstream housing 12. In particular, the first radially-extending arm 74 is configured to directly contact and to seal against an axially-facing surface 122 (e.g., annular surface) of the groove 72 of the body 42, and the second radially-extending arm 76 is configured to directly contact and to seal against the axially-facing surface 104 of the upstream housing 12. As shown, the radially-inner portion 80 of the seal 44 is supported by and/or directly contacts an axially-extending surface 124 (e.g., annular surface) of the groove 72 of the body 42. In the illustrated embodiment, the biasing member 46 is positioned within the cavity 82 defined between the first radially-extending arm 74 and the second radially-extending arm 76 of the seal 44, and the biasing member 46 may be configured to bias the first radially-extending arm 74 and the second radially-extending arm 76 of the seal 44 away from one another along the axial axis 62 to drive the first radially-extending arm 74 against the axially-facing surface 122 of the groove 72 of the body 42 and to drive the second radially-extending arm 76 against the axially-facing surface 104 of the upstream housing 12. As shown, together the seal 44 and the biasing member 46 form an annular seal between the body 42 and the upstream housing 12 without additional components or structures positioned in the groove 72 between the body 42 and the upstream housing 12.
As shown in
With reference to
As shown, the seal 50 is positioned within a seal groove 142 (e.g., annular groove) of the body 48 and is configured to form a seal (e.g., annular seal) between the body 48 and the downstream housing 14. In particular, the first radially-extending arm 136 is configured to contact and to seal against an axially-facing surface 144 of the seal groove 142 of the body 48, and the second radially-extending arm 138 is configured to contact and to seal against the axially-facing surface 134 of the downstream housing 14. In the illustrated embodiment, the biasing member 52 is positioned within a cavity 146 defined between the first radially-extending arm 136 and the second radially-extending arm 138 of the seal 50, and the biasing member 52 may be configured to bias the first radially-extending arm 136 and the second radially-extending arm 138 of the seal 50 away from one another along the axial axis 62 to drive the first radially-extending arm 136 against the axially-facing surface 144 of the seal groove 132 of the body 46 and to drive the second radially-extending arm 138 against the axially-facing surface 134 of the downstream housing 14, while enabling movement of the ball 16 and the body 50 along the axial axis 62.
As shown in
As shown in
In some embodiments, if the upstream pressure Pupstream exceeds the cavity pressure, Pcavity, the upstream pressure, Pupstream, may drive the seal 44 and/or the body 42 away from the axially-facing surface 104 of the upstream housing 12, thereby breaking the seal 128 and enabling fluid flow between the upstream seat assembly 38 and the upstream housing 12 to balance pressure across the upstream seat assembly 38. In operation, the upstream pressure, Pupstream, may increase or decrease due to upstream conditions, fluid supply, temperature, or the like. Similarly, the cavity pressure, Pcavity, may increase or decrease due to cavity conditions, such as temperature or the like. Thus, the disclosed embodiments are configured to automatically relieve the cavity pressure, Pcavity, and/or to maintain a balance between the upstream pressure, Pupstream, and the cavity pressure, Pcavity, even during periods of fluctuating upstream pressure, Pupstream, and/or cavity pressure, Pcavity.
As noted the body 42 may have any suitable geometry or configuration that enables facilitates automatically relieving the cavity pressure, Pcavity, as well enabling the ball valve 10 to block fluid flow when in the closed position 24, as disclosed herein. For example,
Advantageously, in the disclosed embodiments, the seals 44, 48 and their respective bodies 42, 46 may be physically separate components. For example, each of the seals 44, 48 may be a one-piece (e.g., unitary) structure and each of the bodies 42, 46 may be a separate one-piece structure. When installed in the ball valve 10, the seals 44, 48 and the bodies 42, 46 may not be physically attached or fastened together (e.g., by fasteners or adhesives). Such a configuration may enable the seals 44, 48 and the bodies 42, 46 to be formed from different materials. For example, the bodies 42, 46 may be formed from a harder, less elastic, and/or more rigid material as compared to the seals 44, 48, which may enable the bodies 42, 46 to withstand the forces applied to the bodies 42, 46 during operation of the ball valve 10 and enable the seals 44, 48 to provide a flexible seal between the bodies 42, 46 and the housing 11. The disclosed embodiments also enable the seals 44, 48 and the biasing members 46, 52 to deform more than the respective bodies 42, 48 of the seat assemblies 38, 40 during assembly and/or during operation of the ball valve 10. Indeed, in some embodiments, the respective bodies 42, 48 may not substantially deform during assembly and/or during operation of the ball valve 10. More specifically, in certain embodiments, the only substantial deformation of the seat assemblies 38, 40 during assembly and/or operation of the ball valve 10 are to the seals 44, 48 and the biasing members 46, 52. The disclosed embodiments may also facilitate manufacturing of the bodies 42, 46 and/or the seals 44, 48. Additionally, the disclosed embodiments may also facilitate installation, inspection, maintenance, and/or repair of the seat assemblies 38, 40 and their components.
While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).
