GB2280244A - Valve assembly - Google Patents

Valve assembly Download PDF

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Publication number
GB2280244A
GB2280244A GB9315166A GB9315166A GB2280244A GB 2280244 A GB2280244 A GB 2280244A GB 9315166 A GB9315166 A GB 9315166A GB 9315166 A GB9315166 A GB 9315166A GB 2280244 A GB2280244 A GB 2280244A
Authority
GB
United Kingdom
Prior art keywords
valve
seat
valve seat
valve assembly
bore
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.)
Withdrawn
Application number
GB9315166A
Other versions
GB9315166D0 (en
Inventor
Mark Roderick Oliver
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.)
OLIVER VALVES Ltd
Original Assignee
OLIVER VALVES Ltd
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 OLIVER VALVES Ltd filed Critical OLIVER VALVES Ltd
Priority to GB9315166A priority Critical patent/GB2280244A/en
Publication of GB9315166D0 publication Critical patent/GB9315166D0/en
Publication of GB2280244A publication Critical patent/GB2280244A/en
Withdrawn legal-status Critical Current

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
    • 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
    • F16K5/06—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 spherical surfaces; Packings therefor
    • F16K5/0663—Packings
    • F16K5/0689—Packings between housing and plug
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B29C43/10—Isostatic pressing, i.e. using non-rigid pressure-exerting members against rigid parts or dies
    • B29C43/12—Isostatic pressing, i.e. using non-rigid pressure-exerting members against rigid parts or dies using bags surrounding the moulding material or using membranes contacting the moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B29C43/18—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles
    • 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
    • F16K5/08—Details
    • F16K5/14—Special arrangements for separating the sealing faces or for pressing them together
    • F16K5/20—Special arrangements for separating the sealing faces or for pressing them together for plugs with spherical surfaces
    • F16K5/201—Special arrangements for separating the sealing faces or for pressing them together for plugs with spherical surfaces with the housing or parts of the housing mechanically pressing the seal against the plug
    • F16K5/202—Special arrangements for separating the sealing faces or for pressing them together for plugs with spherical surfaces with the housing or parts of the housing mechanically pressing the seal against the plug with conical surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
    • B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
    • B29K2027/18—PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/25—Solid
    • B29K2105/251—Particles, powder or granules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/748—Machines or parts thereof not otherwise provided for
    • B29L2031/7506—Valves

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Taps Or Cocks (AREA)

Abstract

A valve assembly comprises a one-piece valve seat 1 which encapsulates a valve element 2. The seat is of a frusto-conical shape, allowing weight placed on top of the seat to aid in sealing, and is moulded around the element 2 from PTFE powder which is sealed in a flexible mould. The powder is subjected to isostatic pressure, the resultant preform then being sintered. Support rings 3 are positioned in the flow ports through the seat to prevent deformation of the seat. <IMAGE>

Description

VALVE SEAT The present invention relates to a valve seat, particularly but not exclusively to a seat for a ball valve.
Ball valve seats are typically formed of PTFE (polytetrafluoroethylene), and are designed to support the valve ball so that it is in the correct position for effecting sealing, and also to allow the valve ball to be turned to operate the valve without causing excessive wear on the valve components.
The valve seats are typically formed of a number of separate components so that a seal can be made at each junction of the valve with an inlet/outlet port, and around the valve actuator.
Support rings may also be provided to support parts of the seal.
One design of valve seat is known which is formed of two halves of PTFE, one of the halves being placed underneath the valve ball, and the other being placed above the valve ball. The valve ball must be specially modified to allow it to fit within the seat. In order to obtain reasonable sealing around the valve ball, very high pressures must be exerted on the seat from above in order for the two halves to remain in sealing contact.
According to the present invention there is provided a valve assembly having a one-piece valve seat which encapsulates a moveable valve element and having a bore provided therethrough to allow for fluid flow through the valve element.
The valve element is preferably a valve ball, with the seat preferably being formed of PTFE.
Preferably, the valve seat has a tapered shape so that a load applied to its widest end causes pressure to be applied evenly along the side of the seat. Most preferably, the valve seat is of frusto-conical shape. Support rings may be provided in the bore in the valve seat so that the valve seat does not deform under pressure to close the bores therethrough.
Further, smaller bores are also preferably provided in the valve seat, positioned so as to allow a small amount of fluid into the bore in the valve element when the valve element is in its closed position. Pressure present in the valve assembly thus does not cause the valve seat to deform into the bore in the valve element.
The valve seat according to the present invention is preferably formed in an isostatic pressing process. In the isostatic pressing process, PTFE powder may be placed in a flexible mould around the valve ball, the mould then being sealed after filling and pressurised to compress the powder around the valve ball, with the resultant valve seat pre-form then being sintered to fuse together the PTFE particles to form the valve seat.
The present invention also provides a one-piece valve seat which encapsulates a valve element and which has bores provided therethrough to allow for fluid to flow through the valve element.
A specific embodiment of the present invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional view of a valve ball and valve seat according to the present invention; Figure 2 is a side view of the valve seat of Figure 1; Figure 3 is a plan view of the valve seat of Figure 1; Figure 4 is a sectional view of a valve assembly incorporating the illustrated valve seat; and Figure 5 is an end view of the illustrated valve assembly.
Referring to Figs. 1-3 of the drawings, there is illustrated a valve seat 1 surrounding a valve ball 2 and having two support rings 3 placed therein. The valve ball 2 is formed of stainless steel and is of conventional construction, having a recess 4 at the top thereof for actuation of the valve and a bore 5 therethrough.
The valve seat 1 is formed in an isostatic pressing process in which granular PTFE is introduced into a flexible mould positioned around the valve ball 2. The mould is sealed after filling and pressurised in a container to compress the powder around the ball. This produces a PTFE pre-form which is then sintered in a sintering cycle similar to that used for conventional moulded products, to fuse the PTFE particles together. The temperature of the valve seat is raised in the sintering cycle to approximately 3500 C, where it remains for a period of time before a subsequent controlled cooling. This produces a PTFE seat which encapsulates the valve ball apart from apertures allowing access to the valve ball.
The valve seat 1 is of circular cross-section, with a tapered, frusto-conical shape. It is provided with an aperture at its widest end (the top) to allow access to the recess 4 in the valve ball 2 for a spindle, and is also provided with two apertures 6, 7 to corresponding with the bore 5 of the ball, the apertures being spaced 1800 from each other around the wall of the seat. Two further, smaller bores 8, 9 are provided in the wall of the valve seat, also spaced 1800 apart from each other, and positioned between the apertures 6, 7. The two support rings 3 are provided in the valve seat to support the PTFE seat at the apertures 6, 7.
Referring to Figures 4 and 5 of the drawings, the valve seat 1 is placed in a valve housing 10 having a central through bore 11 with enlarged internally threaded ends for connection to pipes (not shown). The valve seat 1 is located in one end of a tapered blind bore 12 in the valve housing transverse to bore 11. The other end of bore 12 ends in a cylindrical collar 12a which is both internally and externally threaded. An externally threaded pusher 13 is engaged in the collar 12a on top of the valve seat 1, the pusher 13 having sealing rings 14, 14a formed of PTFE.
The pusher is screwed into the collar 12a to exert a force on seat 1. Extending through the pusher 13 is a spindle 16, one end of which engages in the recess 4 in the valve ball, the other end of which is a push fit into an actuating handle 17. A nut 18 is threaded onto the spindle 16 which prevents any force acting downwards on the handle 17 causing the spindle 16 to damage the valve ball. The screwing of pusher 13 into collar 12a causes the pusher 13 to exert a force on spindle flange 15, compressing sealing ring 14. Ring 14 seals between pusher 13 and spindle 16 whilst still allowing for rotation of the spindle 16. Further sealing means are also provided between the pusher 13 and the nut 18. A locknut 19 is provided around the cylindrical collar 12a, which may be used to support the valve housing on a panel or the like.
In actuation of the valve, the handle 17 is turned through 900, which moves the ball 2 within the valve seat 1 so that the bore 5 moves either into or out of line with the bore 11 in the housing.
When the valve is closed, the bore 5 is at 900 to the bore 11, and any process fluid which is present in the bore 11 causes pressure to bear on the valve ball 2, hence causing the valve seat 1 to deform slightly allowing some fluid to pass through bores 8, 9 into bore 5. This relieves some pressure on the valve seat 1, preventing it bulging into the bore 5 in the valve ball, which can result in damage to the PTFE on opening of the valve, as the steel edge of the bore can scrape away some of the seal.
The force generated by the pusher 13 being screwed into collar 12a presses down on the valve seat 1, ensuring good sealing between the seat and the housing 10.
Because there are fewer components to the valve seat, the valve housing may be made shorter than was previously possible, thus saving weight and space which can be crucial in a large installation. The valve is also cheaper because of the lower number of components, and is less likely to wear out.
There are no open cavities around the ball for any process medium to accumulate therein, thus making it a hygienic valve.
The valve seat according to the present invention may also be used with multi-port valves such as T- or L-ported ball valves.
In such cases the bore through the valve seat is shaped accordingly, and additional apertures with corresponding support rings may be provided.

Claims (11)

1. A valve assembly having a one-piece valve seat which encapsulates a moveable valve element and which has a bore provided therethrough to allow for fluid flow through the valve element.
2. A valve assembly as claimed in claim 1, wherein the valve element is a valve ball.
3. A valve assembly as claimed in claim 2, wherein the valve ball has a plurality of inlet apertures for a bore therethrough.
4. A valve assembly as claimed in any preceding claim, wherein the seat is formed of PTFE.
5. A valve assembly as claimed in any preceding claim, wherein the valve seat has a tapered shape so that a load applied to its widest end causes pressure to be applied evenly along the side of the seat.
6. A valve assembly as claimed in claim 5, wherein the valve seat is of frusto-conical shape.
7. A valve assembly as claimed in any preceding claim, wherein support rings are provided in the bore in the valve seat so that the valve seat does not deform under pressure to close the bore therethrough.
8. A valve assembly as claimed in any preceding claim, wherein further, smaller bores are also provided in the valve seat, positioned so as to allow a small amount of fluid into a bore in the valve element when the valve element is in its closed position.
9. A valve assembly as claimed in any preceding claim, wherein the valve seat is formed in an isostatic pressing process.
10. A method of manufacturing a valve assembly as claimed in claim 9, wherein the isostatic pressing process comprises the following steps: PTFE powder is placed in a flexible mould around the valve ball, the mould is sealed after filling and pressurised to compress the powder around the valve ball, the resultant valve seat pre-form then being sintered to fuse together the PTFE particles to form the valve seat.
11. A valve seat for use in a valve assembly, the seat being formed in one piece and encapsulating a valve element and having bores provided therethrough to allow for fluid to flow through the valve element.
GB9315166A 1993-07-22 1993-07-22 Valve assembly Withdrawn GB2280244A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9315166A GB2280244A (en) 1993-07-22 1993-07-22 Valve assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9315166A GB2280244A (en) 1993-07-22 1993-07-22 Valve assembly

Publications (2)

Publication Number Publication Date
GB9315166D0 GB9315166D0 (en) 1993-09-08
GB2280244A true GB2280244A (en) 1995-01-25

Family

ID=10739231

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9315166A Withdrawn GB2280244A (en) 1993-07-22 1993-07-22 Valve assembly

Country Status (1)

Country Link
GB (1) GB2280244A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITBZ20090053A1 (en) * 2009-12-09 2011-06-10 Polaris Kg Sas Di Trogmann Matthias & Co BALL VALVE, IN PARTICULAR FOR FOOD LIQUIDS.
CN103542125A (en) * 2012-07-11 2014-01-29 杜天民 Connection ball rod integrated Teflon ball valve and preparing process thereof
CN104819317A (en) * 2014-01-31 2015-08-05 株式会社富士金 Ball valve

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB933080A (en) * 1961-06-27 1963-08-08 Crane Co Rotary ball valve construction
GB994540A (en) * 1963-03-25 1965-06-10 Whitey Research Tool Co Improvements in valves for fluids
GB1211496A (en) * 1968-02-23 1970-11-04 Bayer Ag Mould-closure cock for machines for the production of articles using highly reactive multi-component mixtures
GB1286615A (en) * 1969-12-22 1972-08-23 Goddard Ind Inc Improvements in and relating to fluid control valves
GB1340273A (en) * 1970-05-28 1973-12-12 Whitey Research Tool Co Valves for fluids
GB2077179A (en) * 1980-06-06 1981-12-16 Ugine Kuhlmann Process for providing a polytetrafluoroethylene coating on the inner walls of a hollow metal body
US4615859A (en) * 1981-05-13 1986-10-07 Rogers Corporation Method of manufacture of improved radome structure
EP0417706A2 (en) * 1989-09-12 1991-03-20 CHEMAT GmbH Armaturen für Industrie- und Nuklearanlagen Shut-off valve

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB933080A (en) * 1961-06-27 1963-08-08 Crane Co Rotary ball valve construction
GB994540A (en) * 1963-03-25 1965-06-10 Whitey Research Tool Co Improvements in valves for fluids
GB1211496A (en) * 1968-02-23 1970-11-04 Bayer Ag Mould-closure cock for machines for the production of articles using highly reactive multi-component mixtures
GB1286615A (en) * 1969-12-22 1972-08-23 Goddard Ind Inc Improvements in and relating to fluid control valves
GB1340273A (en) * 1970-05-28 1973-12-12 Whitey Research Tool Co Valves for fluids
GB2077179A (en) * 1980-06-06 1981-12-16 Ugine Kuhlmann Process for providing a polytetrafluoroethylene coating on the inner walls of a hollow metal body
US4615859A (en) * 1981-05-13 1986-10-07 Rogers Corporation Method of manufacture of improved radome structure
EP0417706A2 (en) * 1989-09-12 1991-03-20 CHEMAT GmbH Armaturen für Industrie- und Nuklearanlagen Shut-off valve

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITBZ20090053A1 (en) * 2009-12-09 2011-06-10 Polaris Kg Sas Di Trogmann Matthias & Co BALL VALVE, IN PARTICULAR FOR FOOD LIQUIDS.
CN103542125A (en) * 2012-07-11 2014-01-29 杜天民 Connection ball rod integrated Teflon ball valve and preparing process thereof
CN104819317A (en) * 2014-01-31 2015-08-05 株式会社富士金 Ball valve
JP2015145691A (en) * 2014-01-31 2015-08-13 株式会社フジキン ball valve

Also Published As

Publication number Publication date
GB9315166D0 (en) 1993-09-08

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)