GB2212598A - Diaphragm for diaphragm valves - Google Patents

Diaphragm for diaphragm valves Download PDF

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Publication number
GB2212598A
GB2212598A GB8726757A GB8726757A GB2212598A GB 2212598 A GB2212598 A GB 2212598A GB 8726757 A GB8726757 A GB 8726757A GB 8726757 A GB8726757 A GB 8726757A GB 2212598 A GB2212598 A GB 2212598A
Authority
GB
United Kingdom
Prior art keywords
diaphragm
facing
layer
bead
facing layer
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.)
Granted
Application number
GB8726757A
Other versions
GB8726757D0 (en
GB2212598B (en
Inventor
Keith Bernard Roylance
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 Process Flow Technologies Ltd
Original Assignee
Saunders Valve Co 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 Saunders Valve Co Ltd filed Critical Saunders Valve Co Ltd
Priority to GB8726757A priority Critical patent/GB2212598B/en
Publication of GB8726757D0 publication Critical patent/GB8726757D0/en
Publication of GB2212598A publication Critical patent/GB2212598A/en
Application granted granted Critical
Publication of GB2212598B publication Critical patent/GB2212598B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F16K7/00—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves
    • F16K7/12—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves with flat, dished, or bowl-shaped diaphragm

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Diaphragms And Bellows (AREA)

Abstract

A diaphragm (1) for a diaphragm valve comprises a thin flexible relatively hard facing layer (2) preferably moulded from PTFE and a relatively soft resilient backing layer (3) e.g. of reinforced rubber. The facing layer, preferably in its peripheral zone (4), is formed with a sealing bead (8) which, in use, is clamped against the body flange of a diaphragm body. The backing layer 3 is formed with a pressure bead (9) which overlies the facing preferably in the vicinity of the sealing bead (8), to increase local pressure on the facing layer. <IMAGE>

Description

DIAPHRAGM FOR DIAPHRAGM VALVES This invention relates to a diaphragm for use in a diaphragm valve, that is to say in a valve which includes a flow passage partly defined by the diaphragm, the diaphragm being movable between a closed position in which the diaphragm engages a seat to prevent flow through the valve, and an open position in which the diaphragm is spaced from the seat to permit flow through the valve.
In a conventional diaphragm valve the periphery cf the diaphragm is clamped between a flange provided on the valve body and a flange provided on the bonnet or operating mechanism of the valve. The flanges are secured together by suitable means, for example nuts and bolts, to compress the periphery of the diaphragm therebetween, thereby forming a fluid tight-seal between the diaphragm and the valve body.
It is known to provide a diaphragm for a diaphragm valve in two parts, namely a facing part and a backing part. This technique is employed where a PTFE faced diaphragm is required. In this case, the two part diaphragm comprises a relatively thin facing layer of moulded PTFE and a backing layer of rubber, the backing layer being substantially co-extensive with the facing layer. The backing layer acts to reinforce the facing layer against line pressure, and as a cushion between the facing layer and the compressor. In such two-part diaphragms it is known to form a circular sealing bead on the face of the PTFE to engage the body flange of the valve. When the diaphragm periphery is clamped between the bonnet and body flanges the bead is forced into engagement with the body flange with the intention of forming a fluid seal.
It has been found, however, that in certain sizes of valves operating at high pressures the provision of a sealing bead on the face of the PTFE is not sufficient to provide an adequate seal between the facing and the body.
This can under certain circumstances lead to leakage of line fluid between the facing and the body flange. Bearing in mind that PTFE faced diaphragms are in general only used when a chemically aggressive line fluid is being handled, any leakage of line fluid between the facing and the valve body flange is highly undesirable.
We have now found that the seal between the facing of a two-part diaphragm and the flange of a valve body can be substantially improved if the facing of the diaphragm is provided with a sealing bead, and the backing is provided with a pressure bead which substantially overlies the sealing bead of the facing and applies local pressure to the surface of the facing remote from the sealing bead when the diaphragm is in use.
Accordingly, the present invention provides a diaphragm for a diaphragm valve comprising a thin flexible relatively hard facing layer and a relatively soft resilient backing layer wherein the facing layer is provided on the surface thereof which in use engages the flange of a valve body with a sealing bead, and the backing layer is provided with a pressure bead on the surface thereof which is adjacent the facing layer, the pressure bead being positioned to apply local pressure to the adjacent surface of the facing layer when the diaphragm is clamped to a valve body in use.
The invention will be better understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawing wherein the single Figure is a partly broken away perspective view of a preferred embodiment of diaphragm according to the present invention.
Referring to the drawing, the diaphragm 1 comprises a facing layer 2 moulded from PTFE and a backing layer 3 of reinforced resilient rubber. In use, the peripheral zone 4 of the diaphragm is clamped between the body flange and bonnet flange of a diaphragm valve, the flanges being clamped together by means of bolts or studs which pass through clearance holes 5 provided in the diaphragm.
A pin 6 includes a head (not shown) moulded into the PTFE of the facing layer 2. The pin 6 is a sliding fit within a bore provided in the backing layer 3 whereby relative movement between the pin and the backing layer is permitted in use. The backing layer and facing layer are separately formed, and are assembled together by inserting the pin 6 through the aperture provided in the backing layer. A bayonet pin 7 is then inserted into a cross-bore provided in the pin 6 to facilitate connection of the diaphragm to a compressor assembly, and to prevent accidental removal of the backing layer from the facing layer.
As is conventional with PTFE faced diaphragms, a sealing bead 8 is moulded on the exposed face of the facing layer for contacting the body flange of the valve.
In the prior art the face of the backing layer adjacent to the facing layer was smooth and locally flat.
As a result, when the periphery of the diaphragm was clamped between the bonnet flange and body flange the sealing bead 8 was forced against the flat surface of the body flange and, because PTFE is a relatively hard material, this caused a ridge to appear on the reverse face of the facing (i.e. the face adjacent the backing), this ridge being accommodated by local resilient deformation of the backing material. As a result, the bead 8 was forced against the surface of the body flange with the intention of forming a fluid tight seal.
It has been found, however, that the seal provided by the prior art arrangement is not satisfactory under all circumstances.
We have now found that if a pressure bead 9 is moulded on the surface of the backing layer 3 adjacent the facing layer 2 in the vicinity of the sealing bead 8 substantially improved sealing characteristics between the bead 8 and the body flange are obtained. Compression of the diaphragm periphery will still result in a ridge being produced on the reverse face of the facing, and this ridge will still be accommodated by resilient deformation of the backing. The pressure bead 9 will accordingly be distorted when the diaphragm is clamped in position and will exert a substantially higher local pressure on the reverse face of the facing than was present in the prior art arrangement.
This has been found substantially to improve the seal obtained between the bead 8 and the body flange.
A pressure bead may be provided on the backing to overlie any sealing bead provided on the front face of the facing. For example, if a sealing bead is provided on the facing to engage the seat against which the diaphragm in use seals, a corresponding pressure bead may be provided on the backing.

Claims (4)

1. A diaphragm for a diaphragm valve comprising a thin flexible relatively hard facing layer and a relatively soft resilient backing layer wherein the facing layer is provided on the surface thereof which in use engages the flange of a valve body with a sealing bead, and the backing layer is provided with a pressure bead on the surface thereof which is adjacent the facing layer, the pressure bead being positioned to apply local pressure to the adjacent surface of the facing layer when the diaphragm is clamped to a valve body in use.
2. A diaphragm according to claim 1 wherein the facing layer is provided on the surface thereof which in use engages a seat provided on the valve body to prevent flow through the valve with a sealing bead, and the backing layer is provided with a pressure bead on the surface thereof which is adjacent the facing layer, the pressure bead being positioned to apply local pressure to the adjacent surface of the facing layer when the diaphragm is forced against the seat to close the valve to fluid flow.
3. A diaphragm according to claim 1 or claim 2 wherein the facing layer is of PTFE and the backing layer is of rubber.
4. A diaphragm for a diaphragm valve, substantially as hereinbefore described with reference to the accompanying drawing.
GB8726757A 1987-11-16 1987-11-16 Diaphragm for diaphragm valve Expired - Lifetime GB2212598B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8726757A GB2212598B (en) 1987-11-16 1987-11-16 Diaphragm for diaphragm valve

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8726757A GB2212598B (en) 1987-11-16 1987-11-16 Diaphragm for diaphragm valve

Publications (3)

Publication Number Publication Date
GB8726757D0 GB8726757D0 (en) 1987-12-23
GB2212598A true GB2212598A (en) 1989-07-26
GB2212598B GB2212598B (en) 1991-12-11

Family

ID=10627013

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8726757A Expired - Lifetime GB2212598B (en) 1987-11-16 1987-11-16 Diaphragm for diaphragm valve

Country Status (1)

Country Link
GB (1) GB2212598B (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2251055A (en) * 1990-12-03 1992-06-24 Aro Corp Fluid pressure regulator
DE4215890A1 (en) * 1991-05-15 1992-11-19 Mitsuba Electric Mfg Co METHOD FOR PRODUCING A PRESSURE CONTROL VALVE
FR2694940A1 (en) * 1993-08-04 1994-02-25 Gore & Ass Producing non-porous high-strength densified expanded polytetrafluoroethylene
WO1994004334A1 (en) * 1992-08-19 1994-03-03 W.L. Gore & Associates, Inc. Dense polytetrafluoroethylene articles and a process for producing them
DE29507639U1 (en) * 1995-05-09 1995-07-06 Arca Regler Gmbh Valve
DE29507638U1 (en) * 1995-05-09 1995-07-06 Arca Regler Gmbh Valve
EP0870957A2 (en) * 1997-04-11 1998-10-14 Georg Fischer Rohrleitungssysteme GmbH Diaphragm valve
DE10216661A1 (en) * 2002-04-15 2003-10-30 Gottlob Dietz Gmbh Composite membrane for membrane valve has cover layer as sintered compact vulcanized onto backing layer, with both layers centrally interconnected in flat region with diameter smaller than effective diameter of membrane
DE102013215294A1 (en) * 2013-08-02 2015-02-05 GEMÜ Gebr. Müller Apparatebau GmbH & Co. KG Membrane arrangement for a valve device
US9046180B2 (en) 2012-08-30 2015-06-02 Itt Manufacturing Enterprises Llc. Diaphragm and backing cushion shaping for increased membrane life
US9109707B2 (en) 2009-10-19 2015-08-18 Parker-Hannifin Corporation Seal assembly

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB996847A (en) * 1964-01-15 1965-06-30 Hills Mccanna Co Valve diaphragm structure and method of making same
GB1478239A (en) * 1974-06-19 1977-06-29 Buerkert Gmbh Diaphragm valve

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB996847A (en) * 1964-01-15 1965-06-30 Hills Mccanna Co Valve diaphragm structure and method of making same
GB1478239A (en) * 1974-06-19 1977-06-29 Buerkert Gmbh Diaphragm valve

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2251055B (en) * 1990-12-03 1995-07-19 Aro Corp Fluid pressure regulators
GB2251055A (en) * 1990-12-03 1992-06-24 Aro Corp Fluid pressure regulator
DE4139703B4 (en) * 1990-12-03 2004-12-02 The Aro Corp., Bryan High-pressure fluid regulator
DE4215890C2 (en) * 1991-05-15 2002-06-20 Mitsuba Corp Method of manufacturing a pressure control valve
DE4215890A1 (en) * 1991-05-15 1992-11-19 Mitsuba Electric Mfg Co METHOD FOR PRODUCING A PRESSURE CONTROL VALVE
WO1994004334A1 (en) * 1992-08-19 1994-03-03 W.L. Gore & Associates, Inc. Dense polytetrafluoroethylene articles and a process for producing them
US5374473A (en) * 1992-08-19 1994-12-20 W. L. Gore & Associates, Inc. Dense polytetrafluoroethylene articles
FR2694940A1 (en) * 1993-08-04 1994-02-25 Gore & Ass Producing non-porous high-strength densified expanded polytetrafluoroethylene
DE29507639U1 (en) * 1995-05-09 1995-07-06 Arca Regler Gmbh Valve
DE29507638U1 (en) * 1995-05-09 1995-07-06 Arca Regler Gmbh Valve
EP0870957A2 (en) * 1997-04-11 1998-10-14 Georg Fischer Rohrleitungssysteme GmbH Diaphragm valve
EP0870957A3 (en) * 1997-04-11 1999-07-28 Georg Fischer Rohrleitungssysteme GmbH Diaphragm valve
DE19715164A1 (en) * 1997-04-11 1998-10-22 Fischer Georg Rohrleitung Diaphragm valve
DE10216661A1 (en) * 2002-04-15 2003-10-30 Gottlob Dietz Gmbh Composite membrane for membrane valve has cover layer as sintered compact vulcanized onto backing layer, with both layers centrally interconnected in flat region with diameter smaller than effective diameter of membrane
US9109707B2 (en) 2009-10-19 2015-08-18 Parker-Hannifin Corporation Seal assembly
US9046180B2 (en) 2012-08-30 2015-06-02 Itt Manufacturing Enterprises Llc. Diaphragm and backing cushion shaping for increased membrane life
DE102013215294A1 (en) * 2013-08-02 2015-02-05 GEMÜ Gebr. Müller Apparatebau GmbH & Co. KG Membrane arrangement for a valve device

Also Published As

Publication number Publication date
GB8726757D0 (en) 1987-12-23
GB2212598B (en) 1991-12-11

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20031116