Sprung Seal Retainer

Abstract

A combination valve and coupling has a retainer in the form of a ring which engages a seal. The seal engages the valve closing member and is captured within a pocket in the valve housing by the ring. The ring has tabs in spaced relation about its outer perimeter which engage dogs on the valve housing to retain the ring in contact with the seal. The stiffness of the tabs may be tuned to provide flexibility to the ring and permit the seal to deform when the valve is opened and closed. The tabs have angularly oriented surfaces which engage the dogs and cause axial motion of the ring upon its rotation to adjust the preload between the ring and seal.

Claims

1. A valve for controlling fluid flow through pipe elements connected thereto, said valve comprising: a housing having an inner surface surrounding a central space, a shoulder extending around said inner surface and projecting toward said central space thereby defining a pocket; a valve closing member mounted within said central space and movable between an open position and a closed position; a seal positioned within said pocket, said seal engaging said valve closing member when said valve closing member is in said closed position; and a ring positioned within said central space adjacent to said pocket for retaining said seal therein.

2. The valve according to claim 1, further comprising: a rim extending around said housing, said rim being positioned adjacent to said pocket and surrounding said central space; a plurality of dogs positioned in spaced apart relation to one another around said rim and projecting toward said central space; a plurality of tabs projecting outwardly from an outer perimeter of said ring, said tabs being arranged in spaced apart relation from one another to permit each said tab to pass between two of said dogs for positioning of said ring within said rim, said tabs at least partially overlying said dogs upon rotation of said ring relative to said housing for retaining said ring within said central space.

3. The valve according to claim 2, wherein each one of said tabs comprises a surface oriented angularly with respect to a plane of said ring.

4. The valve according to claim 1, wherein said ring comprises a lip extending about an inner perimeter thereof, said lip projecting out of a plane of said ring toward said seal.

5. The valve according to claim 1, further comprising a plurality of segments attached to one another end to end surrounding said housing and forming a coupling, each said segment having attachment members located at opposite ends, each said segment having arcuate surfaces positioned on opposite sides thereof for engagement with said pipe elements.

6. The valve according to claim 5, wherein said attachment members comprise lugs extending outwardly from opposite ends of each said segment, each said lug defining a hole for receiving a fastener.

7. The valve according to claim 5, wherein said arcuate surfaces project from said segments radially toward said axis.

8. The valve according to claim 5, wherein said plurality of segments comprises no more than two said segments.

9. The valve according to claim 1, wherein said valve closing member comprises a disk mounted on a valve stem rotatably mounted on said housing.

10. A valve coupling for joining pipe elements, said valve coupling comprising: a plurality of segments attached to one another end to end surrounding a central space; a housing captured between said segments, said housing having an inner surface surrounding said central space, a shoulder extending around said inner surface and projecting toward said central space thereby defining a pocket; a valve closing member mounted within said central space and movable between an open position and a closed position; a seal positioned within said pocket, said seal engaging said valve closing member when said valve closing member is in said closed position; and a ring positioned within said central space adjacent to said pocket for retaining said seal therein.

11. The valve coupling according to claim 10, further comprising: a rim extending around said housing, said rim being positioned adjacent to said pocket and surrounding said central space; a plurality of dogs positioned in spaced apart relation to one another around said rim and projecting toward said central space; a plurality of tabs projecting outwardly from an outer perimeter of said ring, said tabs being arranged in spaced apart relation from one another to permit each said tab to pass between two of said dogs for positioning of said ring within said rim, said tabs at least partially overlying said dogs upon rotation of said ring relative to said housing for retaining said ring within said central space.

12. The valve coupling according to claim 11, wherein each one of said tabs comprises a surface oriented angularly with respect to a plane of said ring.

13. The valve coupling according to claim 10, wherein said ring comprises a lip extending about an inner perimeter thereof, said lip projecting out of a plane of said ring toward said seal.

14. The valve coupling according to claim 10, further comprising: attachment members located at opposite ends of each said segment; arcuate surfaces positioned on opposite sides of each said segment for engagement with said pipe elements.

15. The valve coupling according to claim 14, wherein said attachment members comprise lugs extending outwardly from opposite ends of each said segment, each said lug defining a hole for receiving a fastener.

16. The valve coupling according to claim 14, wherein said arcuate surfaces project from said segments radially toward said axis.

17. The valve coupling according to claim 10, wherein said plurality of segments comprises no more than two said segments,

18. The valve coupling according to claim 10, wherein said valve closing member comprises a disk mounted on a valve stem rotatably mounted on said housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is an isometric view of an example embodiment of a valve coupling according to the invention, the valve coupling being shown in a pre-assembled state;

[0015] FIG. 2 is an isometric view of an example valve housing used with the valve coupling of FIG. 1;

[0016] FIG. 2A is an axial view of the valve housing shown in FIG. 2;

[0017] FIG. 3 is a longitudinal sectional view of the valve coupling shown in FIG. 1;

[0018] FIG. 4 is a longitudinal sectional view of a portion of the valve coupling shown in FIG. 1 on an enlarged scale;

[0019] FIG. 5 is a plan view of an example embodiment of a component of the valve coupling shown in FIG. 11;

[0020] FIG. 5A is a partial side view of the component taken at line 5A in FIG. 5;

[0021] FIGS. 6 and 7 are longitudinal sectional views illustrating assembly of a joint using the example valve coupling of FIG. 1; and

[0022] FIG. 8 is an isometric view of the example valve coupling in an assembled state.

DETAILED DESCRIPTION

[0023] FIG. 1 shows an example embodiment of a combination valve and mechanical coupling 10, hereafter referred to as a valve coupling. Valve coupling 10 comprises a plurality of segments, in this example, two segments 12 and 14 attached to one another end to end to surround and define a central space 16. Attachment of segments 12 and 14 is effected by adjustable attachment members 18 located at each end of each segment. In this example the attachment members comprise lugs 20 which extend outwardly from opposite ends of segments 12 and 14, the lugs defining holes 22 that receive adjustable fasteners, such as bolts 24 and nuts 26. Tightening of the nuts 26 draws the segments 12 and 14 toward one another as described below.

[0024] Segments 12 and 14 each have arcuate surfaces 28 positioned on opposite sides 30 and 32 of valve coupling 10. Arcuate surfaces 28 face a longitudinal axis 34 that passes through the central space 16. Arcuate surfaces 28 are engageable with pipe elements when the pipe elements are inserted between the segments 12 and 14 and into central space 16 as described below. The arcuate surfaces 28 may project radially from segments 12 and 14 toward axis 34 to engage circumferential grooves in the pipe elements upon tightening of the attachment members 18 and provide mechanical engagement to secure the pipe elements in end to end relation to form a joint. The arcuate surfaces 28 may also engage pipe elements having plain end, or ends having a shoulder and/or a bead as are known in the art.

[0025] FIGS. 1 and 2 show a valve housing 36 that is positioned within central space 16 and captured between segments 12 and 14. Valve housing 36 has an inner surface 38 which surrounds the central space 16. As shown in FIG. 4, a shoulder 40 extends around the inner surface 38 and projects toward the central space 16 thereby defining a pocket 42. A valve closing member, in this example a disk 44 is mounted within the central space 16 (see also FIG. 1). As shown in FIG. 3, disk 44 is rotatably mounted on valve stems 46 and 48 and movable within housing 36 between an open position and a closed position (shown). Stems 46 and 48 are received within respective bonnets 50 and 52 that extend from the housing 36 and act as bearings for the valve stems. The bonnets 50 and 52 in turn extend through respective openings 54 and 56 in segments 12 and 14. Engagement between bonnets 50 and 52 and the housing 36 helps to stabilize the housing within the central space 16.

[0026] As shown in FIG. 3, a seal 58 is positioned within the pocket 42. Seal 58 comprises a ring that surrounds the central space 16 and sealingly engages the disk 44 when the disk is in the closed position. Additional seals 60, shown in FIG. 3, are positioned between the segments 12 and 14 and the valve housing 36. Seals 60 establish a seal between the segments 12 and 14, the valve housing 36 and pipe elements when a joint is created by tightening the attachment members 18 to draw the segments toward one another and engage the pipe elements.

[0027] FIGS. 3 and 4 show the valve coupling 10 with disk 44 in the closed position, sealingly engaging seal 58. When disk 44 rotates between the open and closed positions the seal 58 is subjected to significant force applied by the disk 44. The force results from the relatively large preload between the perimeter of disk 44 and the surface of the seal 58 necessary to ensure a fluid tight seal. Furthermore, the seal 58 does not experience uniform force during opening and closing of the disk 44. The forces on seal 58 due to opening and closing have several detrimental effects: they subject the seal to repeated high stresses, cause wear, and tend to pull the seal out of its pocket in the valve housing.

[0028] It is expected that these detrimental effects can be mitigated by providing a flexible retainer 62, shown in FIGS. 3-5, to further define the pocket 42 containing the seal 58. As shown in FIG. 5, the example retainer embodiment 62 has the form of a ring 64. Ring 64 has an outer perimeter 66 comprising a plurality of outwardly projecting tabs 68 that are in spaced relation to one another circumferentially around the outer perimeter. Tabs 68 are used to determine the axial stiffness of the ring 64 and thus its deflection as a function of axial load caused when the disk 44 is closed (see FIG. 3) and the valve coupling 10 is subject to internal pressure. Stiffness tuning of tabs 68 may be accomplished by adjusting their thickness, thereby controlling the area moment of inertia of each tab.

[0029] As further shown in FIG. 5, ring 64 may have a flat region 70 on its outer perimeter 66 and a lip 72 which extends about its inner perimeter 74. As shown in FIG. 4, lip 72 projects out of the plane 76 of ring 64 and, is positioned within the central space 16 adjacent to the pocket 42 for retaining the seal 58. The ring 64 is retained within the valve housing 36 by a plurality of dogs 78 (see also FIG. 2). Dogs 78 are positioned in spaced apart relation to one another around a rim 80. Rim 80 is positioned adjacent to the pocket 42 and extends around the housing 36. Dogs 78 project toward the central space 16 and are spaced apart to provide a plurality of gaps 82 that receive the tabs 68 of the ring 64 when the seal 58 is installed as described below.

[0030] The disk seal is assembled by first positioning the seal 58 within the pocket 42. This is readily accomplished by deforming the seal 58 to get it past the dogs 78, as the seal is formed of an elastic, flexible material. Once seal 58 is in place, the ring 64 is positioned, as shown in FIG. 2A, with its tabs 68 aligned with gaps 82 and the flat 70 aligned with a similar flat feature 84 on the rim 80. The ring 64 is also arranged so that its lip 72 faces the seal 58. Ring 64 is then pressed against the seal 58, the seal being compressed between the ring and the shoulder 40 defining the pocket 42. Ring 64 is forced against the seal 58 until the surfaces 86 of tabs 68 that face away from the lip 72 are behind the inner surfaces 88 of the dogs 78 (see also FIGS. 2 and 4). Ring 64 is then rotated about axis 34 to align the tabs 68 with the dogs 78, so that the tabs are at least partially overlying the dogs. Pressure on the ring is then released. As shown in FIG. 4, the space 90 between the shoulder 40 and the ring 64 thus created is smaller than the width of seal 58, and the seal biases the ring 64 against the dogs 78 to secure it in place. The size of space 90 may be adjusted (i.e., made smaller or larger), thereby also adjusting the axial preload of the ring 64 against the seal 58. As shown in FIG. 5, adjustment of the preload is afforded by surfaces 86 of tabs 68, which, as shown in FIG. 5A, are angularly oriented with respect to the plane 76 of the ring 64. This angular orientation causes axial motion of the ring 64 relative to the valve housing 36 (and thus relatively to the seal 58) when the ring 64 is rotated relatively to the housing. The angled surfaces 86 ride against the dogs 78 (see FIG. 2A) upon rotation of the ring 64 and are urged toward the seal 58 (thereby increasing the preload) when rotation is in the clockwise direction as viewed in FIG. 2A. Counterclockwise rotation reduces the preload.

[0031] As shown in FIG. 4, the tabs 68 of ring 64 are captured between the dogs 78 and the valve housing 36. The ring 64 is thus cantilevered about its outer perimeter 66 and its axial stiffness is determined largely by the stiffness of the tabs 68, as they are designed to be the least stiff component among the housing 36 and the dogs 78. The stiffnesses of the tabs 68 are tuned such that ring 64 provides sufficient axial force against seal 58 so that it maintains a fluid tight seal between itself and disk 44 when the disk is closed and subjected to hydraulic pressure. However, the tabs 68 are also flexible enough to permit the space 90 to expand when the seal is subjected to the high, non-uniform forces during opening and closing of disk 44. The flexibility of ring 64 permits it, and thus the seal 58, to deform in response to the opening and closing forces, which lowers the stress on the seal and thereby reduces wear as well as the tendency for the seal to be pulled out of the space 90 when the disk is rotated to the open position. In addition, the use of ring 64 compensates for the loss in elasticity of the seal as it ages. This is accomplished by the ring 64 acting to reduce the size of the space 90 as the seal becomes less stiff.

[0032] In use, as shown in FIG. 6, a valve coupling 10 is provided in a pre-assembled state (see also FIG. 1) with segments 12 and 14 positioned in spaced apart relation sufficient to permit insertion of pipe elements into the central space 16 without disassembling the valve coupling 10. Pipe elements 92 and 94 are then inserted into the central space 16 between the segments 12 and 14 and into respective engagement with seals 60. In this example, the pipe elements have circumferential grooves 96 that receive projecting arcuate surfaces 28 arrayed on opposite sides 30 and 32 of the segments. As shown in FIG. 7, the attachment members 18 (see also FIG. 1) are tightened to draw the segments 12 and 14 toward one another and into engagement with the pipe elements 92 and 94, the projecting arcuate surfaces 28 engaging circumferential grooves 96 in the pipe elements. As the segments 12 and 14 are drawn toward one another the seals 60 are compressed between the segments, the valve housing 36 and the pipe elements 92 and 94 to form a fluid tight joint.

[0033] FIG. 8 shows the final configuration of the valve coupling 10 upon joint installation, the pipe elements not shown for clarity. Note that in this example embodiment the connection members 18 meet in what is known as pad to pad engagement when the valve coupling 10 is properly installed. This design is advantageous because it permits ready visual inspection confirming proper installation, and eliminates the need to tighten the bolts 24 to a specific torque value, though other styles of interface of the connection members known in the art may be used. Such styles include tongue-and-recess interfaces, or interfaces where the connection members do not contact and instead rely on a specified amount of torque exerted on the connection members through bolts or other means to maintain the valve coupling in its final configuration.

[0034] Valves and valve couplings according to the invention which use retainers 62 such as the example ring embodiment 64 are expected to have increased pressure performance, experience less wear and fewer malfunctions due to seals being displaced than valves or valve couplings according to the prior art.