CA1195966A - Seal assembly - Google Patents

Seal assembly

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Publication number
CA1195966A
CA1195966A CA000412004A CA412004A CA1195966A CA 1195966 A CA1195966 A CA 1195966A CA 000412004 A CA000412004 A CA 000412004A CA 412004 A CA412004 A CA 412004A CA 1195966 A CA1195966 A CA 1195966A
Authority
CA
Canada
Prior art keywords
sealing
groove
recess
passage
valve body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000412004A
Other languages
French (fr)
Inventor
Kanaksinh J. Ashar
Vytautas K. Maciulaitis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Crane Co
Original Assignee
Crane Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Crane Co filed Critical Crane Co
Priority to CA000412004A priority Critical patent/CA1195966A/en
Application granted granted Critical
Publication of CA1195966A publication Critical patent/CA1195966A/en
Expired legal-status Critical Current

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Abstract

ABSTRACT OF THE DISCLOSURE

A bi-directional valve comprising a valve body with a recess having a planar surface and a retaining ring having a recess, with the recesses forming a chamber therebetween having an axial centerline parallel to the planar surface and sealing means in said chamber for engagement with a closure means. The sealing means comprising an integral seat ring and a resilient back-up means. The seat ring includes an outer portion, an offset hinged L-shaped portion having a cavity therein to position said back-up means, and a substantially rectangular inner portion having a shoulder ring portion on each side thereof and having a sealing surface with a circum-ferential groove. Pressurization of said sealing means results in substantially perpendicular application of forces of said back-up means and the fluid pressure onto the closure means.

Description

/ --This i.rlvell~;.on r~].ates to bi--dir.cct:ional valves, and in particular to a new sea].;ng means construction having applications in butterfly valves. Butterfly valves have many advantages over other types of valves in fluid flow regulation, most notable being lower cost to the manufac-turer, quickness of opening and low restriction to fluid flow when fully open.
However, these valves generally have been limited to low pres-sure applications because of their inability to .seal tightly at high pressures. ~n some prior art valves, the seals are located in grooves in the valve body which often become dis-lodged when the va]ve is open thereby permitting fluid to flow around the seal. In other prior art valves, high pressure fluid may leak through the valve by flowing between the valve body and seal; while in many other prior art valves, contact between the disc and seal must be made so tigh-t in order to ; prevent leakage that opening the valve, particularly large diameter valves, requires a large torque. Furthermore, in several prior art valves used in high pressure and/or high temperature appli.cations, the seat ring or sealing means loses the desired preloading on the seat ring sealing face as the seat ring expands. In still other floating seal valves, high pressure fluid, which enters the recess when the valve is closed, cannot escape when the valve is opened, thus causing the seal to blow out.
In other floating seat valves, an attempt is made to reduce the tor~ue required to open and close the disc, while improving the retention of the seat ring sealing face as the seat ring e~pands by employing indirect or partial application of resilient means and fluid pressure forces on the sealing face.
It is an object of the present invention to provide an improved bi-directional valve which will neither leak nor 1~59~;
blow out under high pressures and which is operable wi-th a relatively low torque.
A further object of this invention is to p~ovide a reliable, e~ceptional long life, relatively inexpensive and easily replaceable and serviceable valve seat.
It is still a further object of -this invention to provide a bi-directional valve having improved sealing means which fully utilizes direct application of resilien-t means and fluid pressure forces on the sealing face.
I'he bi-directional valve herein is comprised of a valve body having a flow passage therethrough with a recess in proximity to the passage having a planar surface thereon.
A retaining ring detachably affixed to the valve body also has a recess therein. The recesses form a chamber open to the passage having an axial centerline parallel to the planar sur-face of the valve body. The retaining ring is adapted to secure a sealing means in the valve body. A closure means, ; pivotably positioned in the passage and having a peripheral land, is adapted to engage a sealing means.
The sealing means comprises a novel structure of seat ring and resilient back-up means. The seat ring includes an outer portion, a substantially rectangular inner portion having a sealing surface and having a shoulder ring extending on both sides thereof, and an offset hinged L-shaped portion integrally connecting the outer and inner portion. The sealing surface has a circumferential relief groove. The L-shaped portion has a cavity therein adapted to receive a resilient back-up means, whereby in the presence of fluid pressure acting on said sealing means from either side thereof an improved dynamically loaded fluid leak-tight seal is established between said sealing means and the peripheral land of the closure means which results in the substantially perpendicular application oE the resili.(nt hack-up means and fluid pressure forces on the peripheral land.
The present invention provides a bi-directional valve comprising:
A. a valve body having a flow passaye there-through with a recess in proximity -to the passage, the recess having a planar surface wikh a groove therein;
B. a retaining ring surrounding the passage and detachably affixed to said valve body and having a recess therein, the recess having a surface with a groove therein;
C. a chamber open to the passage and formed between the recesses, said chamber having an axial centerline parallel to the planar surface;
D. a closure means pivotally positioned in the passage between an open and a closed position to allow or prevent, respectively, fluid flow therethrough, said closure means having a peripheral land adapted to engage a sealing means;
L. a sealing means including:
an outer portion adapted to be secured between said valve body and said retaining ring;
an offset hinged L-shaped portion integral with said outer portion, said ~-shaped portion having a cavity therein adapted -to receive a resilient back-up means, the cavity having a base surface;
a substantially rectangular inner portion integral with said L-shaped portion, said inner portion having a sealing surface substantially parallel to the base surface, said inner portion having a shoulder ring portion on each side thereof, with the shoulder ring portion on one side projecting into the groove of said valve body and the shoulder rin~ portion on the other side projecting into the groove of said retai~ g ring; and a resilien-t b,~ck-up means positloned in the cavity, said back-up means provides supportive forces on said I,-shaped portion to prevent the collapse thereof, whereby when said sealing means is pressurized by fluid from either side thereof upon closing of said closure means, the parallel relationships of the planar surface with the axial centerline and the sealing surface with the base surface causes said back-up means and fluid directed on said inner portion to apply their combined forces substantially perpendicular to the peripheral land to effect the sealing of said valve.
In drawings which illustrate embodiments of the invention;
; Fig~ 1 is a plan view, in section, of a bu~terfly valve utilizing the seal of this inventlon with the closure means shown in solid lines in the closed position, and in broken lines in the open position.
Fig. 2 is an enlargement of the seal of Fig. 1 with the seal unloaded. Such a condition would occur when the valve is open permitting fluid flow through the valve.
Fig. 3 is an enlargement of the seal of Fig. 1 with the seal in a preloaded condition. Such a condition would occur when the closure means is closed and no line pressure is applied.
Fig. 4 is an enlargement of the seal of Fig. 1 with the seal in a preloaded and pressurized conditionO Such a condition would occur when the closure means is closed and pressure differential across the valve forces line fluid into the channel on one side of the sealing means.
Fig~ S is an enlargement of the seal of Fig. 1 with ~4--1~5~G~

the seal in a preloaded and pressurized condition. Such a condition would occur when the closure rneans is closed and pressure differential across the valve forces line fluid into the channel on the other side of the sealing means.
Referring to the drawings and rnore particularly to Figure 1, a valve, generally represented by reference numeral 10, having a flow passage 12 in valve body 14 is shown located in conduit 18. Valve 10 may be secured in the conduit by welding, bolted flanges, or other common wa~. A valve closure means, such as valve disc 21 having curvilinear peripheral land 22, is shown in solid lines in the closed position and in broken lines in the open position. Disc 21 is secured to stem 16 which protrudes through and is suppor-ted by valve body 14 in such a manner so as to permit axial shifting oE the stem.
Stem 16 has a handle or other means (not shown) attached thereto in the usual manner to provide an axis about which disc 21 may be rotated to open or close the flow passage 12. Sealing means 30 includes a seat ring 31 and resilient back-up means, such as spring 50, and is disposed between valve body 14 and retaining ring 40 which is detachably connected to valve body 14 via fastener 42, as shown. Since the axis of rotation of disc 21 does not coincide with a centerline through seat ring 31, there is eccentric movement of the disc relative to the seat ring causing a faster break-away between disc 21 and seat ring 31 than would otherwise result if the disc and seat ring centerlines coincided. However, -the subject invention may be practiced with coincidence of the disc axis of rotation and the seat ring centerline.
Referring to Figure 2, valve body 14 has a recess therein formed by planar sur~aces 72 and 72~ which are separated by first groove 76 therebetween, and second groove 78 which is adjacent surface i2. Retaining ring 40 has a ~r~Jv - \

recess tllereill coinprislng ~llrfaces 82 and 82~ disposed in juxtaposition to surfaces 72 and 72A, respective].y, and separated by groove 86 therebetween, first surEace 88 continu-ous of surface 82 in a plane normal thereto, and confining s-urface 89 continuous of surface 88 in a plane substantially normal thereto.
The aforementioned recesses of valve body 14 and . retainin~ ring 40 define charnber 60 which is adapted to receive sealing means 30. It should be noted that chamber 60 is so disposed that its axial centerline is positioned parallel to planar surface 72 of valve body 14.
Sealing means 30 is comprised of seat ring 31, made of heat and chemically resistant material such as fluorocarbon urethane or elastomeric polymers, and resilient back-up means, such as a metallic garter-type spring 50. Seat ring 31 includes integrally connected outer portion 32, hinged L-shaped portion 33, and inner portion 34. When the disc is in open position and with retaining ring ~0 secured to valve body 14, outer portion 32 is sized, preferably, so as to be fixedly retained in place in an area defined by second groove 78 and confining surface 89. The volume of mass o-f outer portion 32 is sized larger than the volume of material tha-t can he contained between second groo~e 78 and confining surface 8~, so that, the outer portion becomes compressed therein forming a fluid leak-tight seal around its periphery. To assure fixed reten-tion of the outer portion therein, the area is, preferably, configurated to have narrowest extent along line AA' formed by joining the points of contact of surface 88 to confining surface 89 and of planar surface 72 to second yroove 78.
Though this emobidment is preferred, outer portion 32 can be of any suitable configuration and retained by any suitable means.
Portion 33, integrally joined to outer portion 32, ~S9~;6 contalns cavity 55 the~ein which is adapted ~o receive spring 50 which exerts counter or suppor-tive forces to structure in contact thereto, to prevent the collapse of portion 33 when pressure differential is exerted on the retainlng ring side of seat ring 31. Cavity 55 has planar, base surface 59.
Portion 33 is freely suspended from portion 32 in charnber 60, so that, pressure differential being exerted on either side of seat ring 31 causes hinge-like movement of portions 33 and 34 about line A~l Portion 33 has surface 91 thereon, which is, preferably, of cut back or chamfered configuration thereby ~ermitting a greater unoccupied portion of chamber 60, thus assuring unimpeded hing~-liXe movement of portions 33 and 34 about line AA'. Portion 33, though resilient and flexible, is of non-conical L-shaped configuration which upon loading via fluid pressure assumes a radii arc shape.
Inner portion 34, integral to portion 33~ is sub-stantially of rectangular shape, in section, having sealing surface 36. Inner portion 34 has integral shoulder ring portions 35 and 37 which project into grooves 86, 76, respect-ively, for controlling the amount of projection of seat ring31 into passage 12, and preventing blow out of seat ring 31 when the disc is opened or closed. Sealing surface 36 is of axial extent AD and has circumferential relief groov~ 70 located at its axial centermost portion. Groove 70 is bounded axially by circumferential edges B and C with the axial extent between edges B and C, preferably, larger than axial extents AB, CD located on ei-ther side thereof. Preferably, axial extents AB, CD are equal. Groove 70 is of a radial extent of approximately .010 inches which should be equal to the inter-ference of the disc with seat ring 31. Sealing surface 36 is,preferably, substantially parallel to base surface 56 and may - be generally spherical, conical or other similar shape. Por-~3~i6 tions 35 and 37 are, prefer~lbly, of trape7.0idal configuration, in section. Since chamher 60 is wider than portions 33 and 34, channels ]00, 101 are provided between portions 33, 34 and the recesses of ring 40 and valve hody 14, respectively, facilitating insertion of seat ring 31 into chamber 60, pres-surization and depressurization of cavity 55 and freedom of movement of -the portions during valve operation. Channel 101 is of a greater axial extent than both the axial extent of channel 100 and the amount of permitted axial shifting of the stem.
Referring to Figure 3, in its closed, unpressurized condition, disc 21 wedges land 22 into inner portion 34 causing sealing surface 36 to expand outward and forming two line seals at circumferential edges ~ and C.
In Figure 4, fluid under pressure is directed into channel 100. Fluid pressure component 120 acts normally on portions 33 and 34 causing their pivotal movement about line ~A'. Spring 50, while acting to prevent the collapse of por-tion 33, moves with portion 33 until fully compressed against planar surface 72. The movement of portions 33 and 34 results in axial enlargement of channel 100, and abutting engagement of :inner portion 3~ and shoulder ring portion 37 with surface 72A
and groove 76, respectivelyr preventing -further displacement of inner portion 34.
Fluid pressure component 122 acts radially on portion 33 forcing it and spring 50 downward, transmittin~ through inner portion 34 directly onto sealing surface 36. Due to the parallel relationship of planar surface 72 with centerline LL
of chamber 60 and sealing surface 36 with base surface S9, full fluid pressure component 122 and undeflected spring force component 51 is eY~erted directly onto sealing surface 36 with improved dynamic loading of edges B and C. Therefore, the i6 direct applica-~ions of ~hese forces results in t]leir sub-stantially perpendicular application onto ]and 22 at edges B and C and there~ore improved sealing engagernent of the two line seals formed by -the land and edges B and C.
In Figure 5, fluid under pressure is directed into channel 101. Fluid pressure component 130 acts normally on inner portion 34, and cavity 55 of portion 33 causing pivotal movement of portions 33 and 34 about line AA', axial enlarge-ment of channel 101, and engagement of surface 91 with the ]0 recess of ring 40. Inner portion 34 and shoulder ring portion 35 are in abutting engagement with surface 82A and groove 86, respectively.
Fluid pressure component 130 can be broken down for purposes of explanation, into partial force components 56, 57 and 58. Surfaces 82, 88 act as constraints for por-tion 33 under the loads of partial force componen-ts 56, 58, respectively.
Partial force component 57, as well as undeflected spring Eorce component 51, is transmitted through inner portion 34 directly onto sealing surface 36, providing by their direct applications an improved dynamic loading of edges B and C
resulting in substantially perpendicular application of these forces onto land 22 at edges B and C and therefore improved sealing engagement of the two line seals formed by the land and edges B and C.
As sealing surface 36 wears with use, the apices of edges B and C will gradually erode and each line seal each edge forms with land 22 will become an axially expanding band seal. Ultimately, the two band seals will merge into a single band seal. Specifically, the apex of edge B will widen out-ward towards A and F the center point of groove 70; while, theapex of edge C will widen outward towards D and F. ~herefore, axial extent AB is, preferably, initially equal to axial extent S~i6 CD so that the axial exten-t oE both band seals ~i]l he sub-stantially equal throughout a substan-tial portion of the life of seat ring 31.
Although a certain embodiment has been described and illustrated, modification may be made herein, as by adding, combining or subdividing par-ts or by substi-tuting equivalents or by applying the invention to other types of valves or mechanisms while retaining advantages and benefits of the inven-tion, which itself is defined in the following claims.

Claims (9)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A bi-directional valve comprising:
A. a valve body having a flow passage therethrough with a recess in proximity to the passage, the recess having a planar surface with a groove therein;
B. a retaining ring surrounding the passage and detachably affixed to said valve body and having a recess therein, the recess having a surface with a groove therein;
C. a chamber open to the passage and formed between the recesses, said chamber having an axial centerline parallel to the planar surface;
D. a closure means pivotally positioned in the passage between an open and a closed position to allow or prevent, respectively, fluid flow therethrough, said closure means having a peripheral land adapted to engage a sealing means;
E. a sealing means including:
an outer portion adapted to be secured between said valve body and said retaining ring;
an offset hinged L-shaped portion integral with said outer portion, said L-shaped portion having a cavity therein adapted to receive a resilient back-up means, the cavity having a base surface;
a substantially rectangular inner portion integral with said L-shaped portion, said inner portion having a sealing surface substantially parallel to the base surface, said inner portion having a shoulder ring portion on each side thereof, with the shoulder ring portion on one side projecting into the groove of said valve body and the shoulder ring portion on the other side projecting into the groove of said retaining ring; and, a resilient back-up means positioned in the cavity, said back-up means provides supportive forces on said L-shaped portion to prevent the collapse thereof, whereby when said sealing means is pressurized by fluid from either side thereof upon closing of said closure means, the parallel relationships of the planar surface with the axial centerline and the sealing surface with the base surface causes said back-up means and fluid directed on said inner portion to apply their combined forces substantially perpendicular to the peripheral land to effect the sealing of said valve.
2. The bi-directional valve of Claim 1, wherein each of the pair of shoulder ring portions is of substantially trapezoidal configuration.
3. The bi-directional valve of Claim 1, wherein said outer portion is secured in a portion of said chamber and is of a volume of mass larger than the volume of material that can be contained in the portion, so that said outer portion is com-pressed therein forming a fluid leak-tight seal about its periphery.
4. The bi-directional valve of Claim 1, wherein said L-shaped portion is resilient, flexible and substantially of non-conical arcuate configuration, whereby under fluid pressure said L-shaped portion forms a radii-arc shape.
5. The bi-directional valve of Claim 1, wherein each of the grooves is of substantially trapezoidal configuration.
6. The bi-directional valve of Claim 1, wherein the sealing surface has a circumferential relief groove therein.
7. The bi-directional valve of Claim 6, wherein the relief groove is located in the axial centermost portion of the sealing surface and the portions of the sealing surface on either side thereof are of equal axial extent.
8. The bi-directional valve of Claim 6, wherein the relief groove is of an axial extent greater than the portions of the sealing surface on either side thereof.
9. A bi-directional valve comprising:
A . a valve body having a flow passage therethrough with a recess in proximity to the passage, the recess having a planar surface with a groove therein;
B. a retaining ring surrounding the passage and detachably affixed to said valve body and having a recess therein, the recess having a surface with a groove therein;
C. a chamber open to the passage and formed between the recesses, said chamber having an axial centerline parallel to the planar surface;
D. a disc secured to a stem and pivotally positioned in the passage about the stem between an open and a closed position to allow or prevent, respectively, fluid flow there-through, said disc having a peripheral land adapted to engage a relief groove;
E. a stem supported by said body so as to permit axial shifting; and F. a sealing means including;
an outer portion adapted to be secured between said valve body and said retaining ring;
an offset hinged L-shaped portion integral with said outer portion, said L-shaped portion having a cavity therein adapted to receive a resilient back-up means, the cavity having a base surface;
a substantially rectangular inner portion integral with said L-shaped portion, said inner portion having a sealing surface with a circumferential relief groove, with the sealing surface substantially parallel to the base surface and the relief groove bounded by a pair of circumferential edges, said inner portion having a first shoulder ring portion on one side thereof projecting into the groove of said valve body, and a second shoulder ring portion on the other side thereof pro-jecting into the groove of said retaining ring with a channel formed between each shoulder ring portion and its respective groove, whereby the axial extent of the channel formed between the first shoulder ring portion and its respective groove is greater than that formed between the second shoulder ring por-tion and its respective groove and the former is greater than the amount of permitted axial shifting of said stem; and, a resilient back-up means positioned in the cavity, said back-up means provides supportive forces on said L-shaped portion to prevent the collapse thereof, whereby upon closing of said closure means, the peripheral land forms a line seal with each one of the pair of circumferential edges, whereby when said sealing means is pressurized by fluid from either side thereof upon closing of said closure means, the parallel relationships of the planar surface with the axial centerline and the sealing surface with the base surface causes said back-up means and fluid directed on said inner portion to apply their combined forces substantially perpendicular to the peripheral land to enhance the sealing of said valve at the two line seals.
CA000412004A 1982-09-23 1982-09-23 Seal assembly Expired CA1195966A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000412004A CA1195966A (en) 1982-09-23 1982-09-23 Seal assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000412004A CA1195966A (en) 1982-09-23 1982-09-23 Seal assembly

Publications (1)

Publication Number Publication Date
CA1195966A true CA1195966A (en) 1985-10-29

Family

ID=4123640

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000412004A Expired CA1195966A (en) 1982-09-23 1982-09-23 Seal assembly

Country Status (1)

Country Link
CA (1) CA1195966A (en)

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