MXPA96006076A

MXPA96006076A - Valve assembly having improved valve seat

Info

Publication number: MXPA96006076A
Application number: MXPA/A/1996/006076A
Authority: MX
Inventors: P Kusmer Daniel; A Frenzel Robert
Original assignee: Keystone International Holdings Corp
Priority date: 1994-06-03
Filing date: 1995-06-02
Publication date: 1998-10-23

Abstract

A valve comprising a valve body having a first end, a second end, and a through opening forming a fluid flow passage and a wall surrounding a portion of the fluid flow passage, the fluid flow passage defining an axis that is co-axial with the wall. A valve element is rotatably mounted in the valve body, the valve element having an annular, radiused sealing surface and being rotatable around a second axis perpendicular to the first axis passing through the fluid flow passage. A valve seat assembly is disposed in the valve body for sealing engagement with the sealing surface of the valve element, the valve seat assembly being axially displaced from the second axis toward the first end of the valve body, the valve seat assembly comprising a seal ring of a resilient, plastic material and having an annular radially inwardly facing first surface for sealing engagement with the sealing surface on the valve element and an annular, radially outwardly facing second surface, an annular radially outwardly facing groove being formed in the second surface. An elastomeric backing ring is disposed in the groove, the backing ring being circular in cross section and having a center-line defined by a first plane passing through the center of the backing ring perpendicular to the first axis, the engagement between the sealing surface on the valve element and the first surface on the seal ring being substantially annular, line contact when the valve element is in the closed position and in the absence of any fluid pressure acting on the valve element, the line contact engagement lying in a second plane axially displaced from the first plane in a direction away from the second axis toward the first end of the valve body. There are also provided retaining means for retaining the valve seat assembly in the valve body.

Description

VALVE ASSEMBLY OUE HAS IMPROVED VALVE SEAT DESCRIPTION The present invention relates to a valve having a rotary valve element and more particularly, to a valve having an improved seat ring assembly. Valves that have rotary valve elements - for example, butterfly valves - are well known. In certain types of butterfly valves, the valve seat ring that seals the disk is surrounded by a support member that is generally elastic in nature and serves to force or pre-load the seat surface of the valve seat. seat ring against the disc, when the disc is in the closed position. Typical of such a valve seat design is shown in U.S. Patent No. 3,642,248. In particular, that patent shows a seal assembly that can be used in a butterfly valve and that comprises a wear ring that could be used to seal the valve disc, the wear ring that is provided with a groove which faces radially outward, annular in which is placed an elastomeric backing ring which forces or pre-loads the wear ring in seal coupling with the disc.

In the arrangement shown in U.S. Patent No. 3,642,248, the seal contact between the periphery of the disc and the wear ring occurs over a large area in which it must be characterized as an interference fit, so it needs requirements. torque relatively high to seat or separate the disc. Therefore, it is an object of the present invention to provide a valve having an improved valve seat. Another object of the present invention is to provide a valve having an improved valve seat assembly consisting of a seal ring and an elastomeric backup ring, which preloads the seal ring in engagement with the seal disc. The valve. Still another object of the present invention is to provide a valve seat for use with a butterfly valve, in which the seal between the disc and the valve seat is made by substantial in-line contact when there is no pressure in the valve. fluid acting on the disc, so that the amount of torque required to seat or separate the disc is minimized. The above objects and other objects of the present invention will become apparent from the drawings, the description given herein and the appended claims. The valve of the present invention comprises a valve body having a first end, a second end and a through opening that forms a fluid flow conduit, the valve body includes a wall surrounding a portion of the fluid flow conduit , the fluid flow passage defines a first axis coaxial with the wall. A disk valve element is rotatably mounted in the valve body, the valve member having a rounded, annular seal surface and which is rotatable about a second axis perpendicular to the first axis. A valve seat assembly is placed in the valve body for the coupling seal with the seal surface of the disk, the valve seat assembly being axially positioned from the second axis towards the first end of the valve body. The valve seat assembly comprises a seal ring formed of a resilient, plastic material and having a first inwardly facing, annular surface that engages the seal surface on the disk in seal form, when the disk It is in the closed position. The seal ring has a radially outward, annularly facing, annular groove formed in a second facing surface radially outwardly. The valve seat assembly further includes an elastomeric backing ring placed in a groove in the seal ring, the backup ring which is circular in cross section and having a central line defined by a first plane passing through the center of the backup ring is perpendicular to the first axis. The coupling between the seal surface on the disc and the first surface on the seal ring is substantially an annular contact line, when the disc is in the closed position and in the absence of any fluid pressure acting on the disc. The coupling contact line between the disc and the ring seal is placed in a second plane axially displaced from the first plane in a direction separating it from the second axis towards the first end of the valve body. The valve further includes a retaining means for retaining the valve seat assembly in the valve body. The valve seat assembly and retainer means are axially insertable and removable from the valve body through the first end of the valve body. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front elevational view of the valve of the present invention. Figure 2 is a cross-sectional view taken along lines 2-2 of Figure 1.

Figure 3 is a fragmented view, enlarged partially in section showing the relationship between the valve seat and the disc, with the disc in the closed position and without fluid pressure acting on the disc. Figure 4 is a view similar to Figure 3 with the exception that the disc is subjected to fluid pressure in the direction shown by the arrow. Figure 5 is a view similar to Figure 3 with the exception that the disc is subjected to fluid pressure in an opposite direction to that shown in Figure 4. Although the present invention will be described with particular reference to a disc valve - for example a butterfly valve - it is understood that the valve of the present invention can consist of any quarter-turn valve having a rotary valve element with a rounded seal surface, in such a way as to allow coupling in the line of contact with the valve seat to make the seal. First with reference to Figures 1 and 2, the valve of the present invention consists of a valve body 10 optionally provided, as shown, with lugs 12 projecting laterally outwards, positioned around the periphery of the valve body 10. and having holes 14 for screws or bolts to allow the valve to be connected to projections of an attached pipe. The valve body 10 comprises a central cylindrical section 16 from which a neck portion 18 and a relief portion, lower 20, the neck portion 18 and the relief portion 20 are projecting diagonally in relation to each other. The cylindrical section 16 defines a through opening 22 which forms a fluid flow passage through the valve, the through opening 22 is formed by the coaxial cylindrical walls 24 and 26, the cylindrical wall 26 as shown, being of a diameter greater than the cylindrical wall 24. Positioned in the through opening 22 is a valve element 28 of the disc type having a rounded, annular seal surface 29, the valve element 28 which serves to control the flow of the fluid through the fluid flow conduit defined by the through opening 22. A lower shaft 30 extends through a hole 32 in the relief 20. The lower shaft 30 is rotatably mounted in the hole 32 by means of a bushing 34 received in a counter-bore. 36 of the hole 32. An end layer 38 is secured to the relief 20 by the screws 40, a seal 37 forming a seal. An upper shaft 42 extends through the hole 44 in the neck portion 18. The packed rings 46, received in the counter-bore 48 of the hole 44, serve to provide a fluid-tight seal between the neck portion 18 and the upper shaft 42. A stuffing box 50 is also received in the counter-bore 48, the stuffing box 50 includes an O-shaped ring 52 for sealing around the upper shaft 42. A packing conversion bridge 54 having a central depression or concavity 56 is received on the shaft 42 by means of a hole 58 by means of the bridge 54. The screws 60 extend through the holes in registers in the bridge 54 and the projection 64 projecting radially outwardly from the neck portion 18. The nuts 66 received The screws 60 can be tightened, as will be apparent, to engage the depression 56 with the upper part of the stuffing box 50 to compress the row of rings 46 of the em and securing the fluid-tight seal between the neck 18 and the arrow 42. The lower arrow 30 is secured to the disk 28 by means of a bolt 68 received in a first projecting lock 70 of the disk 28. The upper shaft 42 is secured to the disk 28 by means of bolts 72 extending through a second latch 74 projecting from disk 28 in a manner well known to those skilled in the art. Therefore, the disc 28 is rotatably mounted on the straight part 22 of the valve body 10 and can be rotated 90 ° manually or by means of an actuator to control the flow of fluid through the valve. For this purpose, the upper shaft 42 is provided with planar portions 76. To effect the seal around the periphery of the disc 28, an annular valve seat assembly, generally shown as 78 and described more fully in the following, is provided. The valve seat assembly 78 is maintained in the valve body 10 by means of a valve seat fastener assembly generally shown as 84 and described more fully in the Co-pending Application serial number, filed at the same time as the present , entitled "Valve Assembly" and on behalf of Daniel F. Kusmer and Robert A. Frenzel as inventors (Kusmer Application), the Kusmer Application is incorporated herein for all purposes. With reference to Figures 3-5, it can be seen that the wall 26 defines a radially inward, annular facing surface having a radially inwardly extending, annularly extending groove 86. The slot 86 is intercepted by a hole 88 (see Figure 1) axially drilled in the valve body 10, the intersection of the hole 88 and the slot 86 forming an opening in the lower part of the slot 86. The fastener assembly 84 includes a fastener ring 92 having a peripheral surface 94, which is shaped and dimensioned in such a way that the peripheral surface 94 faces intimately the radially inward facing surface defined by the wall 26 when the ring 92 is received in the valve body 10. The ring 92 also has a groove 96 facing radially outwardly, extending in an annular manner which, when the ring 92 is received in the valve body 10, is in register with the groove 86. , slots 86 and 96 therefore define a channel that extends annularly. The ring 92 has a first side 95 provided with a notch 93, which intersects the slot 96 in a manner more fully described in the Kusmer Application and a wire member 98 is received in the annular channel formed by the slots 86 and 96 and effectively prevents any axial movement of the ring 92 in the valve body 10. The wire member 98 has a first end 106 having a leg portion extending generally transverse, preferably at 90 °, with respect to the long axis of the member of wire 98. In order to install the ring 92 in the valve body 10, the ring 92 is placed in the valve body 10 in such a way that the notch 93 is in register with the opening formed in the lower part of the slot 86. The leg portion of the end 106 of the wire member 98 is then passed through the groove 93 and placed in the cavity in the groove 86. This effectively fixes the first end 1C6 of the wire member 98 in the groove. annular anura 86. Then the ring 92 can be rotated counterclockwise (with reference to Figure 1) - i.e. in one direction along the length of the wire member 98 separating from the first end 106. This will result in threading the wire member 98 into the channel formed by the slots 86 and 96. At such point, when the ring 92 has been rotated to where the notch 96 is again in register with the cavity in the slot 86 , the wire member 98 will be completely positioned in the channel formed by the slots 86 and 96 in register. Accordingly, a clamped ring 92 will be effectively trapped in the valve body 10 and any axial movement is prevented, thereby ensuring that the valve seat assembly 78 can not be separated by line pressure. The fastener ring 92 has a second side 100 provided with a projection 102 that projects axially, which extends annularly. The valve body 10 includes an annularly extending projection that faces annularly, 1 projection 102 and 104 face one another. In this way a first axially, annularly facing recess 106 defined by the projection 104 and a second axially facing, annular recess 108 defined partially by the projection 102 is defined. As seen, the recess 106 has a width radial less than the recess 108, the recesses 106 and 108 face each other. The projections 102 and 104 also partially define an annularly extending channel 110, which intercepts the recesses 106 and 108 and opens in the flow conduit 22. In effect, the recesses 106 and 108 and the channel 110 form a cavity for annular valve seat, generally in T-shape. With particular reference to Figure 3, the valve is shown with the disc 28 in closed position - ie, the surface 29 in seal engagement with the surface of the annular seat 122 on the seal ring 80. The seal ring 80 includes an annular, centrally extending body portion 122 which is received in the channel 110, a first annular projecting portion 114, integral with the body portion 112 and received in the slot 106 and a second annular projection portion 116 integral with the body portion 112 and received in the recess 108. As can be seen, the central body portion 112, the projection portion 114 and the projection portion 116 is They are dimensioned and shaped to fit intimately in the valve seat cavity formed by the channel 110, the recess 106 and the recess 108, respectively. In the embodiment shown in Figure 3 - that is, when the disc 28 is in the closed position the seal ring 80 in seal engagement and without pressure acting on the disc 28, the seal contact between the disc 28 and the disc 28 seal ring 80 occurs at the substantially annular contact line, the contact line which is indicated by the letter "A" in Figure 3. With reference to Figure 3, it can be seen that the centerline of the backup ring at 82 , indicated by dotted line B is moved axially from line A to the axis of rotation of disk 28. At the point of fact, the centerline of the backup ring at 82 is placed in a plane that is perpendicular to an axis that passes through the fluid flow conduit 22 -that is, substantially parallel to the axis of rotation of the disc 28. In addition, it can be seen that the seal ring 80 has a radially outwardly extending slot 120, extending in Annular form that is complementary io in the shape for the backup ring 82, such that the backup ring 82 snaps into the slot 120. The centerline of the slot 120 is also placed in the plane passing through the centerline of the backing ring 82. In this way it will be apparent that the backing ring 82 is positioned asymmetrically with respect to a centerline which stops through the body portion 112 of the seal ring 80 - ie, both of the slot 120 and the backing ring 82 is displaced axially towards the axis of rotation of the disc 28. This geometry provides unique benefits more fully explained in the following. Reference is now made to Figure 4 to show the interaction of the disc 28 and the seat assembly 78 by applying pressure against the disc 28 in a direction as shown by arrow C. In the position shown in Figure 4 with the disc 28 in the closed position, the pressure acting in the direction of the arrow C, will deflect the disc 28 in the direction of the arrow C - that is, the peripheral seal surface 29, will push in interference, on the surface of relatively large contact area with the surface of the annular seat 122 formed in the seal ring 80. Additionally, the fluid pressure will enter the valve seat cavity and exert a force against the seal ring 80, moving projection 116 in abut contact with second surface 100 of retaining ring 92 and body portion 112 in contact with projection 102. Now with reference to Figure 5, the interaction of disc 28 and seat assembly valve 78, is shown in connection with the fluid pressure acting on the disc 28 in the direction of the arrows D - that is, in a direction towards the axis of rotation of the disc 28. This condition, again with the disc 28 in the closed position, the disc 28 will be deflected towards the axis of rotation of the disc 28 - that is, in the direction of the arrows D. At the same time, the fluid pressure will enter the valve cavity and force the ring seal 80 to rotate around the backup ring 82 with the total result that while the contact line between the surface 29 and the surface 122 will still be made, the annular contact line will be axially moved in such a way that a pl anus passing through the contact line, indicated by A, and perpendicular to an axis passing through the flow path 22 - that is, parallel to the axis of rotation of the disc 28 - will now be placed intimately adjacent to the plane which passes through the center line (indicated by B) of the backup ring 82. It is also noted that rotation of the seal ring 80 around the backup ring 82 will rotate or oscillate to the seal ring 80 as shown, Such a way that the body portion 112 will be in engagement with the projection 104. However, because this rotational or oscillating movement of the seal ring 80 around the backup ring 82, the projecting portion 114 only lightly, if not is that in no way, it will couple the back part of the recess 106. In this way, the contact line will be maintained under the conditions shown in Figure 5, with effective fluid pressure seal; and however, because such a contact line, the amount of torque required to seat and separate the disc 28 is kept to a minimum. Although the surface 122 of the seal ring 80 is shown to be rounded, it will be appreciated that the contact line could still be achieved if the surface 122 were truncated cone, since the surface 29 on the disc 28 is rounded. It is also noted that at all times, the backing ring 82, which is a relatively soft elastomeric material, maintains an effective seal between the seal ring 80 and the valve body 10. As noted above, the ring of seal 80 is made of a plastic, elastic material such as, for example, certain rubbers, Teflon®, nylon, etc. The backup ring 82 will generally be made of elastomeric material that is softer than the seal ring material 80, such materials include certain rubbers and other well-known elastomeric materials used in the formation of 0-rings and the like. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. Therefore, it should be understood that within the scope of the appended claims, the invention may be practiced in any other manner than specifically described herein.

Claims

CLAIMS 1. A valve characterized in that it comprises: a valve body having a first end, a second end and a through opening forming a fluid flow conduit, the valve body includes a wall surrounding a portion of the flow conduit of fluid, the fluid flow conduit defines an axis coaxial with the wall; a valve member rotatably mounted on the valve body, the valve member having an annular rounded seal surface, and being rotatable about a second axis perpendicular to the first axis, - a valve seat assembly positioned on the body valve for the seal coupling with the seal surface of the valve element, the valve seat assembly moving axially from the second axis towards the first end, the valve seat assembly comprises: a seal ring formed of a plastic material, elastic and having a first facing surface radially inward, annular for sealing engagement with the sealing surface on the valve element and a second facing surface radially outward, annular, a groove that faces radially outward, annular forming on the second surface, an elastomeric backing ring placed in the groove ra, the backup ring that is circular in cross section, the backup ring having a central line defined by a first plane passing through the center of the backup ring perpendicular to the first axis, the coupling between the seal surface on the valve element and the first surface on the seal ring which is in a contact line, substantially annular when the valve element is in the closed position and in the absence of any fluid pressure acting on the valve element, the coupling contact line is placed in a second plane axially displaced from the first plane in a direction separated from the second axis towards the first end of the valve body; and a retaining means for retaining the valve seat assembly in the valve body. The valve according to claim 1, characterized in that the annular radially outward facing groove has a cross-sectional configuration that is complementary to the cross-sectional configuration of the backup ring. The valve according to claim 1, characterized in that the valve body and the retaining means cooperate to define a valve seat cavity that extends annularly to receive the valve seat assembly. The valve according to claim 3, characterized in that the cavity of the valve seat, when viewed in the cross section, has a first recess that faces axially, annularly, the first recess facing the first end of the valve body and a second axially facing recess, the second recess facing the first recess and the valve cavity further including an annularly extending channel, intersecting the first and second recesses and the opening in the flow conduit. The valve according to claim 4, characterized in that the first recess has a radial width less than the radial width of the second recess. The valve according to claim 5, characterized in that the seal ring includes a central body portion received in the channel, a first projecting portion integral with the body portion and extending within the first recess and a second portion. integral projection with the body portion extending into the second recess, the body portion and the first and second projections cooperate to define the second surface. 7. The valve according to claim 5, characterized in that the central body portion, the first projecting section and the second projecting portion are dimensioned and configured to fit intimately in the channel, the first recess and the second recess, respectively. The valve according to claim 7, characterized in that the slot facing outwardly on the second surface has a central line that is placed on the first plane and the first plane placed axially towards the first axis from a central line of the body portion that is placed in a third plane parallel to the first and second planes. The valve according to claim 1, characterized in that the first surface on the seal ring is rounded. SUMMARY A valve comprising a valve body having a first end, a second end and a through opening forming a fluid flow passage and a wall surrounding a portion of the fluid flow passage, the fluid flow passage which defines an axis that is coaxial with the wall. A valve member is rotatably mounted in the valve body, the valve member having a rounded, annular seal surface and which is rotatable about a second axis perpendicular to the first axis passing through the fluid flow conduit. A valve seat assembly is positioned in the valve body for seal engagement with the seal surface of the valve member, the valve seat assembly which is axially positioned from the second axis towards the first end of the valve body, the valve seat assembly comprises a seal ring of a resilient plastic material and having a first radially inwardly facing, annular facing surface for sealing engagement with the seal surface on the valve element and a second one surface facing radially outward, annular, a radially outwardly facing, annular groove that forms on the second surface. An elastomeric backing ring is placed in the slot, the backup ring being circular in cross section and having a center line defined by a first plane passing through the center of the backup ring perpendicular to the first axis, the coupling between the seal surface on the valve element and the first surface on the seal ring which is substantially annular, the contact line when the valve element is in the closed position and in the absence of any fluid pressure acting on the valve element, the coupling contact line is placed in a second axially displaced plane of the first plane in a direction separating from the second axis towards the first end of the valve body. Retention means are also provided for retaining the valve seat assembly in the valve body.