Patent Application
20140175319
The present disclosure relates generally to multi-section valve bodies and, more specifically, to multi-section valve bodies having face seals.
Control valves (e.g., sliding stem valves, rotary valves, axial flow valves, globe valves, etc.) are commonly used in industrial processes, such as oil and gas pipeline distribution systems and chemical processing plants, to control the flow of process fluids. Some known control valves include a valve body comprised of multiple sections (e.g., pieces, portions, components, parts, bodies). Ball valves are an example of control valves that are often composed of multiple sections. Ball valves are favored in certain applications because they are extremely durable, provide tight shutoff, and are effective in high flow systems.
Known ball valves utilize a ball (e.g., a spherically-shaped disk, a flow control member, etc.) having a hole (e.g., a bore, a port, a passageway) through its center and disposed within a passageway of a valve body. A shaft is attached to the ball via an aperture in the valve body and is to rotate the ball between an open position and a closed position. In the open position, the ball is rotated such that the hole in the ball aligns with both ends of the valve. In the closed position, the ball is rotated such that the hole is perpendicular to the ends of the valve and the fluid passageway through the valve is blocked.
The ball in a ball valve has a larger diameter than a diameter of the valve passageway. Thus, ball valves are usually manufactured and assembled in sections around the ball, especially in the instance with larger ball valves where price and practicality more greatly affect the manufacturing and assembly processes. Some known ball valves have three main body sections: a middle body section, which includes the ball, and two tailpiece body sections on opposing sides of the body section. The tailpieces must properly seal against the body section to prevent the leakage of process fluids. The tailpieces include flanges having faces that are coupled or clamped to respective ends of the body section. The tailpieces also include outside flanges that may be coupled or clamped to the end of a pipe such as, for example, in a piping distribution system.
Many known tailpieces also utilize male extensions (e.g., sleeves, annular protuberances, circular protrusions, etc.) that extend into the passageway or bore of the body section. Outer annular walls of the male extensions sealingly engage an inner wall of the passageway or bore of the body section to align and seal the valve from leakage at each joint (e.g., the boundary between a tailpiece and the body). The annular walls include glands (e.g., grooves, cavities, etc.) to hold a seal such as, for example, an o-ring. The geometry (e.g., profile) of the gland is to retain the seal during assembly such as, for example, during a vertical assembly operation. Compression of the o-ring creates a seal between the annular walls of the male extensions and the inner surface of the body section is to prevent the leakage of process fluid outside of the valve.
However, problems exist with the above-mentioned sealing interface (i.e., the boundary between the annular wall and the inner surface of the body section). The seal is achieved by squeezing the o-ring disposed within the glands between the annular wall and the inner surface of the body section and, thus, the tolerances between these two surfaces must be very tight. A relatively narrow range of compression of the o-ring is needed to ensure proper sealing. Therefore, a gap between the annular wall and the inner surface of the body section must be large enough for the parts to be assembled and small enough to ensure proper o-ring compression (e.g., squeeze), but not overly tight such that an end of the body section catches and damages the o-ring, which can be a problem during the assembly process. Also, during operation, it is known that pressure from the process fluids can force a portion of the o-ring seal (or the entire o-ring) out of the gland and down into the gap between the annular wall and the inner surface of the body section. Thus, proper o-ring squeeze is lost and a leak path forms in the gap.
To ensure proper alignment, these known ball valves are often assembled vertically. Also, larger valves with heavy components are assembled vertically by using a crane or other mechanical device to assist in lifting and aligning the three main body sections. However, during assembly of these large and heavy body sections, it is difficult to detect if the o-ring has been damaged (e.g., torn, ripped, cut). As the body section slides down over the male extension of the first tailpiece, the relative movement may shear the o-ring and damage it within the annular gland.
Although these inefficiencies are described in relation to a ball valve body, these problems can occur with any valve having multiple body sections and, more specifically, with valves having male end sealing surfaces.
In one example, an apparatus includes a first body defining a first portion of a valve passageway and having a fluid flow axis, the first body having a first sealing surface substantially perpendicular to the fluid flow axis and a first annular wall substantially parallel to the fluid flow axis, the first body having an annular cavity defined in the first sealing surface to receive a seal. The example apparatus includes a second body having a bore defining a second portion of the valve passageway, the second body having a first end surface to be substantially parallel to the first sealing surface, wherein the first sealing surface is to engage the first end surface and the first annular wall is to extend into the bore of the second body when the first body is coupled to the second body.
In another example, a valve body includes a first tail portion defining a first portion of a passageway and having a first flange with a first annular groove, the first annular groove extending into the first flange in a direction substantially parallel to a longitudinal axis of the passageway, the first tail portion having a first annular wall section extending from the first flange. The valve body also includes a second tail portion defining a second portion of the passageway and having a second flange with a second annular groove, the second annular groove extending into the second flange in a direction substantially parallel to the longitudinal axis of the passageway, the second tail portion having a second annular wall section extending from the second flange. The valve body also includes a valve portion having a bore defining a third portion of the passageway, the valve portion having a first end surface and a second end surface opposite the first end surface, wherein the first flange engages the first end surface and the first annular wall section extends into at least a portion of the bore, and wherein the second flange engages the second end surface and the second annular wall section extends into at least a portion of the bore.
In yet another example, an apparatus includes a first body defining a first portion of a valve passageway and having a fluid flow axis, the first body having a first sealing surface substantially perpendicular to the fluid flow axis and a first male extension extending from the first sealing surface. The apparatus also includes a second body defining a second portion of the valve passageway, the second body having a second sealing surface substantially perpendicular to the fluid flow axis and a second male extension extending from the second sealing surface. The apparatus also includes a third body having a bore defining a third portion of the valve passageway, the third body having a first end surface to be substantially parallel to the first sealing surface and a second end to be substantially parallel to the second sealing surface. The apparatus also includes first means for sealing to prevent a flow of fluid between the first sealing surface of the first body and the first end of the third body when the first body is coupled to the third body and second means for sealing to prevent the flow of fluid between the second sealing surface of the second body and the second end of the third body when the second body is coupled to the third body.
Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify the same or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. Additionally, several examples have been described throughout this specification. Any features from any example may be included with, a replacement for, or otherwise combined with other features from other examples.
An exploded cross-sectional view of a known multi-section valve is shown in
The first and second tailpieces 20 and 24 include respective male extensions 46 and 48 with annular walls 50 and 52. The male extensions 46 and 48 guide the first and second tailpieces 20 and 22 into the body 22 to ensure proper alignment. The first and second annular walls 50 and 52 include respective glands 54 and 56 for holding seals 58 and 60. The first and second seals 58 and 60 create a seal between the first and second annular walls 50 and 52 and an inner surface 62 (e.g., a bore) of the body 22 to prevent the leakage of process fluids from the valve 10. The glands 54 and 56 also assist in seal retention during assembly such as, for example, during vertical assembly where the seal may move due to gravity.
An assembled cross-sectional view of the known multi-section valve 10 is shown in
However, this type of seal configuration can present difficulties when assembling and operating the valve. As can be appreciated from
During assembly, because this type of seal is a static seal, the relative movement between the tailpieces 20 and 24 and the body 22 often damages the seals 58 and 60. For example, as shown in
The example multi-section valve bodies described herein have lower tolerance requirements, reduce seal damage during assembly, prevent seal extrusion during high pressure operation, and greatly reduce manufacturing and maintenance costs. In general, the example multi-section valve bodies described herein include a valve body composed of three bodies (e.g., portions, sections, pieces, components), specifically, first and second tailpieces coupled to opposites sides of a body (e.g., a middle body section). The first and second tailpieces have male extensions that extend into a bore of the body and faces with annular glands that seal against respective ends of the body. In some examples, a half-dovetail gland is formed in the faces to retain a seal (e.g., an o-ring) during assembly. The example multi-section valve bodies described herein utilize a face-type seal. Throughout this description, the example multi-section valve bodies are referred to as example ball valves. However, the teachings of this disclosure may be applied to any type of valve body having multiple bodies (e.g., portions, section, pieces, components) and, more particularly, to multi-section valve bodies capable of accommodating face-type seals.
In particular, an example multi-section valve body described herein includes first and second tailpieces coupled to first and second ends of a body. The body includes a number of flow control components (e.g., a flow control member, a seal, a shaft, a spherically-shaped disk, a bearing, etc.). The first and second tailpieces include sealing faces for sealingly engaging respective ends of the body. The first and second tailpieces also include male extensions, which extend into a bore of the body when the first and second tailpieces are coupled to the respective ends of the body.
The first and second tailpieces also include annular glands (e.g., grooves, cavities) defined in the respective sealing faces. The glands receive seals such as, for example, o-ring type seals for creating a sufficiently tight seal between the sealing faces and the respective ends of the body to prevent the leakage of process fluid. The annular glands defined in the sealing faces of the tailpieces, as opposed to those defined in annular walls of the male extensions, reduce tolerance requirements between the diameter of the inner surface of the body and the outer diameter of the male extensions. The faces of the tailpieces may be compressed tightly onto the ends of the body and, thus, any remaining gap is eliminated and a full seal gland (e.g., a four sided gland) is formed.
In some examples, the annular glands are Parker half-dovetail or full-dovetail style glands. The example multi-section valve bodies described herein are also effective in extremely high pressure systems because the location of the seal, and elimination of a gap, prevents the seals from being forced out of the glands due to process fluid pressure.
The body 104 also includes a shaft 116 coupled to the ball 108, and a dome attenuator 118 which, for example, may be used to condition fluid flow (e.g., reduce noise and/or cavitation in the fluid flow). The first tailpiece 102 has a first face 120 (e.g., a flange, a sealing surface) for engaging a first end 122 of the body 104. The second tailpiece 106 has a second face 124 for engaging a second end 126 of the body 104. In the example shown, the first and second faces 120 and 124 are substantially perpendicular to the passageway 110 or fluid flow axis. The three valve body sections 102-106 may be coupled together via mechanical fasteners, such as, for example, bolts, or any other mechanical fastener(s).
The first and second tailpieces 102 and 106 include respective male extensions 128 and 130 with annular walls 132 and 134. The male extensions 128 and 130 extend substantially perpendicular to the first and second faces 120 and 124 and, thus, the annular walls 132 and 134 extend substantially parallel to the passageway 110 or fluid flow axis. The first and second faces 120 and 124 include respective glands 136 and 138 (e.g., annular grooves) for holding seals 140 and 142. The first and second glands 136 and 138 protrude into respective faces 120 and 124 in a direction substantially parallel to the fluid flow axis or longitudinal axis of the valve 100. The first and second seals 140 and 142 create a seal between the first and second faces 120 and 124 and the first and second ends 122 and 126 of the body 104 to prevent the leakage of process fluids from the valve 100. In the example shown, the seals 140 and 142 are o-ring seals. However, in other examples, the seals 140 and 142 may be, for example, spring-loaded seals, elastomeric seals, omni-seals, gaskets (e.g., flat gaskets, spiral wound gaskets, etc.), or any other type of seal capable of being compressed or deformed. The body 104 has an inner bore surface 144 to receive the first and second annular walls 132 and 134 of the respective tailpieces 102 and 106.
An assembled cross-sectional view of the multi-section valve 100 is shown in
Unlike the male o-ring gland style tailpieces described above in
As illustrated in
As shown, the first and second annular glands 136 and 138 are Parker half-dovetail glands. In the example shown, the half-dovetail glands 136 and 138 are defined by three walls, one of which is tapered inward. The tapered profile of the glands keeps the seals 140 and 142 within the glands 136 and 138 during, for example, assembly of the valve body 100. For example, with larger valves, the second tailpiece 106 may be lowered down onto the body 104 and the profile of the gland 138 retains the seal 142 within the gland 136 to ensure proper assembly. In other examples, the first and second annular glands 136 and 138 may be full Parker dovetail glands, or any other shaped gland for receiving a seal and retaining the seal in the gland.
The example valve 100 having multiple bodies described herein has lower tolerance requirements, reduces seal damage during assembly, prevents seal extrusion during high pressure operation, and greatly reduces manufacturing and maintenance (e.g., weld repair) costs. The face seal and profiled gland provide more effective sealing than a male gland type seal and assist in seal retention during assembly. The example multi-section valve 100 also decreases tolerance stack-up that affect o-ring squeeze. With improved o-ring squeeze, the example multi-section valve body provides more optimum (e.g., reliable) operating life and, thus, lower maintenance costs.
Although certain example apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
