WO2001065156A2 - Fire safe ring seal for valves - Google Patents

Fire safe ring seal for valves Download PDF

Info

Publication number
WO2001065156A2
WO2001065156A2 PCT/US2001/005749 US0105749W WO0165156A2 WO 2001065156 A2 WO2001065156 A2 WO 2001065156A2 US 0105749 W US0105749 W US 0105749W WO 0165156 A2 WO0165156 A2 WO 0165156A2
Authority
WO
WIPO (PCT)
Prior art keywords
ring
pocket
bonnet
plug
fire seal
Prior art date
Application number
PCT/US2001/005749
Other languages
French (fr)
Other versions
WO2001065156A3 (en
Inventor
Gordon M. Smith
John A. Hotz
Colin G. Knight
Jeffrey R. Conley
Gene T. Krupala
Original Assignee
General Valve, Inc.
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 General Valve, Inc. filed Critical General Valve, Inc.
Priority to MXPA02008374A priority Critical patent/MXPA02008374A/en
Priority to JP2001563821A priority patent/JP2003525411A/en
Priority to CA002401154A priority patent/CA2401154A1/en
Priority to BR0108934-0A priority patent/BR0108934A/en
Publication of WO2001065156A2 publication Critical patent/WO2001065156A2/en
Publication of WO2001065156A3 publication Critical patent/WO2001065156A3/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K27/00—Construction of housing; Use of materials therefor
    • F16K27/06—Construction of housing; Use of materials therefor of taps or cocks
    • F16K27/062—Construction of housing; Use of materials therefor of taps or cocks with conical plugs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K5/00—Plug valves; Taps or cocks comprising only cut-off apparatus having at least one of the sealing faces shaped as a more or less complete surface of a solid of revolution, the opening and closing movement being predominantly rotary
    • F16K5/02—Plug valves; Taps or cocks comprising only cut-off apparatus having at least one of the sealing faces shaped as a more or less complete surface of a solid of revolution, the opening and closing movement being predominantly rotary with plugs having conical surfaces; Packings therefor
    • F16K5/0257—Packings

Definitions

  • the present invention relates generally to plug valves and more particularly to a fire safe closure seal ring system which replaces the conventional gasket and permits smaller bolting, smaller bonnets and increased effectiveness and dependability.
  • the current state of the art in fire safety for plug valves consists of graphite gaskets and packing rings.
  • the prior art consists of asbestos and graphite materials which are sufficiently compliant in response to compressive loads to effect a seal which is sufficiently sturdy to support pressure and mechanical loads. These materials are also sufficient to withstand fire temperatures higher than 1400 degrees Fahrenheit. They are also resistant to most chemical substances.
  • a circular gasket has a thickness of .030 inches and a width of 3/8 to 3/4 inches.
  • the gasket is deployed outwardly from the valve body bore !D to the inboard side of the body closure bolts thereby requiring the body to have a flat, polished circular area for installation.
  • the body closure bolts are required to maintain pressure vessel integrity despite hydrostatic loads, valve operator thrust and the gasket sealing load which is not insubstantial. It would be highly advantageous if the flat graphite gasket of the prior art could be replaced by a seal which is more effective and requires lower degrees of bolt loading.
  • the fire seal of the present invention replaces the prior art gasket with a compact fire safe ring seal.
  • the seal of the present invention differs from the prior art gasket in two principal ways. First, the seal is shaped differently. Unlike the prior art gasket, the inventive seal is not flat. It is preferably round, square, triangular, trapezoidal or other non-flat cross-section so that it effects the seal with less bolt loading. Second, the seal is located in a more outboard chamfered region of the body flange that is trapped against the adjacent closure flange. Because it is thicker, the seal is more compliant. The compliance combined with the chamfer configuration, yield significant sealing effectiveness without the same degree of bolt loading. Lower bolt loading permits use of smaller components. The body flange can be smaller and the closure flange can be thinner. The result is a lighter and lower cost valve structure. In addition, the bolts can be smaller which also reduces weight and costs.
  • FIG. 1 is a cross-sectional view of a plug valve implemented with a fire safe ring seal system in accordance with a preferred embodiment of the invention
  • FIG. 2 is an enlarged view of the portion of the plug valve labeled "see FIG. 2" in FIG. 1 with a bolt omitted for visual advantage;
  • FIG. 3 is a three-dimensional view of a ring seal used in the preferred embodiment of FIG. 1
  • FIG. 4 is an elevational view of the ring seal of FIG. 3;
  • FIG. 5 is a side view of the ring seal
  • FIG. 6 is an enlarged view of the portion of the ring seal labeled "see FIG. 6" in FIG. 5.
  • a plug valve 10 comprises a body 12 enclosing a rotatable plug 14 having a flow passage 16.
  • the valve is shown in the open configuration with the flow passage 16 aligned with connecting pipes (not shown) secured to the valve 10 by connecting flanges 18.
  • Plug 14 has a pair of slips 15 affixed on opposing sides of the plug to stop flow when the plug is rotated 90 degrees to place flow passage 16 in a direction perpendicular to that shown in FIG. 1.
  • the plug is integral to an upper trunnion 20 and a iower trunnion 26.
  • Upper trunnion 20 is controlled by an operator 22 and a handle 24 to position plug 14 in either the opened or closed position.
  • plug valve is referred to as a double block and bleed valve because it permits the fluid in the valve body to be bled out when the slips seal against both the inlet and the outlet ports.
  • the fire ring seal system disclosed herein is not limited to such valves and maybe used advantageously in any valve, pump or other structure where fire safe sealing of an enclosed, pressurized fluid is desirable.
  • a bottom cover 28 is secured to the lower end of body 12 by bolts 29.
  • the upper end of body 12 is enclosed by a bonnet 30 secured by a bolt ring 32 and bolts 34.
  • Bonnet 30 has a flange 36 which is in contact with the upper surface 38 of body 12.
  • the upper surface 38 has a chamfer 40 to form an annular pocket 42 which receives the fire ring seal 44 of the present invention.
  • Below chamfer 40 there is an O-ring 46 mounted in the main portion of the bonnet 30.
  • fire ring seal 44 is circular and has a trapezoidal cross-section with one axial end of the circular seal being thicker than the other axial end. The thicker axial end is positioned at the upper edge of chamfer 40 and as seen in FIG. 2, is in direct compressive contact with flange 36 of the bonnet 30.
  • the fire ring seal 44 is preferably a GRAFOIL® ring available from Union Carbide Company of New York City. Because of the unique chamfer configuration for positioning ring seal 44, the seal is more compliant and is subjected to both lateral and longitudinal compression to effect fire safe sealing.
  • the shape and dimensions of the ring seal 44 relative to the shape and dimensions of pocket 42 permit effective sealing with less bolt loading from bolts 34. More particularly, the axial length of ring seal 44 (A + B in FIG. 6) is preferably greater than the depth of chamfer 40 along the axial direction of plug 14 by the length B (of FIG. 6) and the thickness C of ring seal 44 is preferably about the same as the width of chamfer 40 along the radial direction of plug 14.
  • ring seal 44 and pocket 42 assure that the ring seal overfills the chamfer pocket prior to connection of the bonnet 30 to body 12. Moreover, it assures excellent sealing with the tightening of bolts 34 to a loading level well below that required with the flat gasket sealing of the prior art. This permits the use of smaller bolts. Moreover, lower bolt loading requirements also permit a reduction in the size of body surface 38, a reduction in the size of bonnet flange 36 and thus a lighter and lower cost plug valve which still meets all fire safety regulatory specifications.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Taps Or Cocks (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Safety Valves (AREA)
  • Gasket Seals (AREA)
  • Sliding Valves (AREA)

Abstract

a seal system comprises a non-flat cross-section, fire resistant compressible ring (44) and an annular pocket (42) formed between two engagting surfaces (36, 38) of a pressure vessel such as a plug valve (10). The pocket is formed by providing a chamfer (40) in one such surface (38) which is then enclosed by the other such surface (36). The ring is compressed within the pocket to substantially fill the pocket upon mating of the two surfaces.

Description

FIRE SAFE CLOSURE RING SEAL SYSTEM FOR PLUG VALVES
FIELD OF THE INVENTION
The present invention relates generally to plug valves and more particularly to a fire safe closure seal ring system which replaces the conventional gasket and permits smaller bolting, smaller bonnets and increased effectiveness and dependability.
BACKGROUND ART
The current state of the art in fire safety for plug valves consists of graphite gaskets and packing rings. The prior art consists of asbestos and graphite materials which are sufficiently compliant in response to compressive loads to effect a seal which is sufficiently sturdy to support pressure and mechanical loads. These materials are also sufficient to withstand fire temperatures higher than 1400 degrees Fahrenheit. They are also resistant to most chemical substances.
Conventional gaskets for plug valves tend to be flat and wide. For example, in one typical embodiment of prior art plug valves, a circular gasket has a thickness of .030 inches and a width of 3/8 to 3/4 inches. The gasket is deployed outwardly from the valve body bore !D to the inboard side of the body closure bolts thereby requiring the body to have a flat, polished circular area for installation. The body closure bolts are required to maintain pressure vessel integrity despite hydrostatic loads, valve operator thrust and the gasket sealing load which is not insubstantial. It would be highly advantageous if the flat graphite gasket of the prior art could be replaced by a seal which is more effective and requires lower degrees of bolt loading.
SUMMARY OF THE INVENTION
The fire seal of the present invention replaces the prior art gasket with a compact fire safe ring seal. The seal of the present invention differs from the prior art gasket in two principal ways. First, the seal is shaped differently. Unlike the prior art gasket, the inventive seal is not flat. It is preferably round, square, triangular, trapezoidal or other non-flat cross-section so that it effects the seal with less bolt loading. Second, the seal is located in a more outboard chamfered region of the body flange that is trapped against the adjacent closure flange. Because it is thicker, the seal is more compliant. The compliance combined with the chamfer configuration, yield significant sealing effectiveness without the same degree of bolt loading. Lower bolt loading permits use of smaller components. The body flange can be smaller and the closure flange can be thinner. The result is a lighter and lower cost valve structure. In addition, the bolts can be smaller which also reduces weight and costs.
OBJECTS OF THE INVENTION
It is therefore a principal object of the present invention to provide a fire safe ring seal system for plug valves and which results in lighter and lower cost structures.
It is another object of the invention to provide an improved plug valve which has a non-flat fire safe ring seal and chamfered seal pocket implementation for reducing bolt loading.
It is still an additional object of the invention to reduce body flange, closure flange and bolting size and weight in plug-type valves by providing a more effective fire safe seal and locating the seal in a more effective location on the valve.
It is still another object of the invention to provide an improved fire-safe ring seal system for vessels designed to contain fluids under pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
The aforementioned objects and advantages of the present invention, as well as additional objects and advantages thereof, will be more fully understood hereinafter as a result of a detailed description of a preferred embodiment when taken in conjunction with the following drawings in which:
FIG. 1 is a cross-sectional view of a plug valve implemented with a fire safe ring seal system in accordance with a preferred embodiment of the invention;
FIG. 2 is an enlarged view of the portion of the plug valve labeled "see FIG. 2" in FIG. 1 with a bolt omitted for visual advantage;
FIG. 3 is a three-dimensional view of a ring seal used in the preferred embodiment of FIG. 1
FIG. 4 is an elevational view of the ring seal of FIG. 3;
FIG. 5 is a side view of the ring seal;
FIG. 6 is an enlarged view of the portion of the ring seal labeled "see FIG. 6" in FIG. 5.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to the accompanying figures and FIGs. 1 and 2 in particular, it will be seen that a plug valve 10 comprises a body 12 enclosing a rotatable plug 14 having a flow passage 16. The valve is shown in the open configuration with the flow passage 16 aligned with connecting pipes (not shown) secured to the valve 10 by connecting flanges 18. Plug 14 has a pair of slips 15 affixed on opposing sides of the plug to stop flow when the plug is rotated 90 degrees to place flow passage 16 in a direction perpendicular to that shown in FIG. 1. The plug is integral to an upper trunnion 20 and a iower trunnion 26. Upper trunnion 20 is controlled by an operator 22 and a handle 24 to position plug 14 in either the opened or closed position.
This form of plug valve is referred to as a double block and bleed valve because it permits the fluid in the valve body to be bled out when the slips seal against both the inlet and the outlet ports. However, it will be understood that the fire ring seal system disclosed herein is not limited to such valves and maybe used advantageously in any valve, pump or other structure where fire safe sealing of an enclosed, pressurized fluid is desirable. A bottom cover 28 is secured to the lower end of body 12 by bolts 29. The upper end of body 12 is enclosed by a bonnet 30 secured by a bolt ring 32 and bolts 34.
Bonnet 30 has a flange 36 which is in contact with the upper surface 38 of body 12. As seen best in FIG. 2, the upper surface 38 has a chamfer 40 to form an annular pocket 42 which receives the fire ring seal 44 of the present invention. Below chamfer 40 there is an O-ring 46 mounted in the main portion of the bonnet 30. As seen best in FIGs. 3-6, fire ring seal 44 is circular and has a trapezoidal cross-section with one axial end of the circular seal being thicker than the other axial end. The thicker axial end is positioned at the upper edge of chamfer 40 and as seen in FIG. 2, is in direct compressive contact with flange 36 of the bonnet 30. The fire ring seal 44 is preferably a GRAFOIL® ring available from Union Carbide Company of New York City. Because of the unique chamfer configuration for positioning ring seal 44, the seal is more compliant and is subjected to both lateral and longitudinal compression to effect fire safe sealing. The shape and dimensions of the ring seal 44 relative to the shape and dimensions of pocket 42 permit effective sealing with less bolt loading from bolts 34. More particularly, the axial length of ring seal 44 (A + B in FIG. 6) is preferably greater than the depth of chamfer 40 along the axial direction of plug 14 by the length B (of FIG. 6) and the thickness C of ring seal 44 is preferably about the same as the width of chamfer 40 along the radial direction of plug 14. These relative dimensions of ring seal 44 and pocket 42, assure that the ring seal overfills the chamfer pocket prior to connection of the bonnet 30 to body 12. Moreover, it assures excellent sealing with the tightening of bolts 34 to a loading level well below that required with the flat gasket sealing of the prior art. This permits the use of smaller bolts. Moreover, lower bolt loading requirements also permit a reduction in the size of body surface 38, a reduction in the size of bonnet flange 36 and thus a lighter and lower cost plug valve which still meets all fire safety regulatory specifications.
Having thus disclosed a preferred embodiment of the invention, it being understood that many alternative shapes, sizes and locations are contemplated for the ring seal and chamfer chamber, what is claimed is:

Claims

1. A plug valve (10) having a body (12) containing a rotatable plug (14), the plug having a passage (16) for selective alignment with connecting inlet and outlet pipes,
the body being enclosed by a bonnet (30) and a bottom cover (28) to form a sealed chamber within said body, said bonnet having a flange (36) engaging a top surface
(38) of said body and having a fire seal (44) therebetween, wherein said seal comprises a non-flat compressible heat resistant ring, said ring being located in a chamfered region (40) of said top surface of said body, said chamfered region forming an annular pocket (42) shaped to receive said ring.
2. A plug valve according to claim 1, wherein said ring has a trapezoidal cross-
section.
3. A plug valve according to claim 1 or 2, wherein said ring has an
uncompressed length which exceeds the depth of said pocket.
4. A plug valve according to claim 1 , 2 or 3, wherein said ring has a size and
cross-section for compressibly filling said annular pocket upon attachment of said
bonnet to said body.
5. A plug valve according to any one of the preceding claims wherein said ring has a size and shape for applying sealing forces in two orthogonal directions upon attachment of said bonnet to said body.
6. A fire seal apparatus for use in an enclosed vessel containing a fluid under pressure, the vessel having at least two mating surfaces which at least partially overlap at a junction to define an annular pocket (42) formed by a chamfer (40) in one of the mating surfaces, said fire seal apparatus comprising a heat resistant
compressible ring (44) wherein said ring has a non-flat cross-section and is positioned within said annular pocket (42), the arrangement being such that the other of said mating surfaces compresses said ring into said pocket.
7. A fire seal apparatus according to claim 6, wherein said ring has a trapezoidal cross-section.
8. A fire seal apparatus according to claim 6 or 7, wherein said ring has an uncompressed length which exceeds the depth of said pocket.
9. A fire seal apparatus according to any one of claims 6, 7 or 8, wherein said
ring has a size and cross-section for compressibly filling said annular pocket upon attachment of said bonnet to said body.
10. A fire seal apparatus according to any one of claims 6-9, wherein said ring has a size and shape for applying sealing forces in two orthogonal directions upon attachment of said bonnet to said body.
PCT/US2001/005749 2000-02-28 2001-02-23 Fire safe ring seal for valves WO2001065156A2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
MXPA02008374A MXPA02008374A (en) 2000-02-28 2001-02-23 Fire safe closure ring seal system for plug valves.
JP2001563821A JP2003525411A (en) 2000-02-28 2001-02-23 Fire resistant ring seal system for plug valve
CA002401154A CA2401154A1 (en) 2000-02-28 2001-02-23 Fire safe closure ring seal system for flug valves
BR0108934-0A BR0108934A (en) 2000-02-28 2001-02-23 Plug-in valve and fire seal

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US51387500A 2000-02-28 2000-02-28
US09/513,875 2000-02-28

Publications (2)

Publication Number Publication Date
WO2001065156A2 true WO2001065156A2 (en) 2001-09-07
WO2001065156A3 WO2001065156A3 (en) 2002-02-14

Family

ID=24044957

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/005749 WO2001065156A2 (en) 2000-02-28 2001-02-23 Fire safe ring seal for valves

Country Status (5)

Country Link
JP (1) JP2003525411A (en)
BR (1) BR0108934A (en)
CA (1) CA2401154A1 (en)
MX (1) MXPA02008374A (en)
WO (1) WO2001065156A2 (en)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3554488A (en) * 1968-08-19 1971-01-12 Texsteam Corp Plug valve
US3848849A (en) * 1973-06-29 1974-11-19 Vapor Corp Fluid control valve
CA1135677A (en) * 1979-10-04 1982-11-16 Michael A. Calvert Ball valves
US4566482A (en) * 1985-06-27 1986-01-28 Stunkard Gerald A Top entry trunnion ball valve
US4637421A (en) * 1986-05-15 1987-01-20 Stunkard Gerald A In-line repairable top entry ball valve

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Also Published As

Publication number Publication date
BR0108934A (en) 2003-01-21
CA2401154A1 (en) 2001-09-07
WO2001065156A3 (en) 2002-02-14
JP2003525411A (en) 2003-08-26
MXPA02008374A (en) 2002-12-13

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