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WO2000079175A1 - Dispositif de restriction de debit pour tuyaux - Google Patents

Dispositif de restriction de debit pour tuyaux Download PDF

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Publication number
WO2000079175A1
WO2000079175A1 PCT/GB2000/002123 GB0002123W WO0079175A1 WO 2000079175 A1 WO2000079175 A1 WO 2000079175A1 GB 0002123 W GB0002123 W GB 0002123W WO 0079175 A1 WO0079175 A1 WO 0079175A1
Authority
WO
WIPO (PCT)
Prior art keywords
pipe
cross
member according
linked
linked polyolefin
Prior art date
Application number
PCT/GB2000/002123
Other languages
English (en)
Inventor
Derek Muckle
Graham Crawford
Original Assignee
Uponor Limited
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 Uponor Limited filed Critical Uponor Limited
Priority to AU55420/00A priority Critical patent/AU5542000A/en
Publication of WO2000079175A1 publication Critical patent/WO2000079175A1/fr

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
    • F16K7/00—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves
    • F16K7/02—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves with tubular diaphragm
    • F16K7/04—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves with tubular diaphragm constrictable by external radial force
    • F16K7/06—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves with tubular diaphragm constrictable by external radial force by means of a screw-spindle, cam, or other mechanical means
    • F16K7/061—Screw clamps

Definitions

  • This invention relates to inhibiting fluid flow, and more particularly to a valve member for temporarily inhibiting the flow of fluid in a distribution main and to a new water distribution system.
  • Distribution mains for example, water distribution pipe systems, frequently have the requirement that the flow of fluid needs to be stopped or diverted, for example, when carrying out damage repairs, leakage repairs, relining, mains extension or service connections, or inspection of the system or a part thereof .
  • Commonly metal valves are inserted into the pipe system at discrete locations so that the water supply can be turned off or diverted at that point .
  • the metal valves currently in use are large and cumbersome, subject to corrosion, particularly when used with buried pipe systems, expensive, and frequently fail in service due to leakage or blockage.
  • a technique which has been developed and widely applied in the gas industry is that of "squeeze off", in which a clamping device is applied to a polyethylene gas main which locally deforms the main by flattening in order to cut off the gas fiow whilst repair or rehabilitation work is carried out.
  • This method works well in practice, but it is well recognised that polyethylene pipes can be squeezed off in this way only once, since repeated applications of the squeeze off technique very quickly lead to stress cracking of the pipe.
  • current regulations demand that a fresh section of pipe must be chosen that can be no closer than 3 to 4 pipe diameters of the original squeeze off point. The requirement to expose a fresh section of pipe can be inconvenient, particularly where buried pipe systems are concerned.
  • the squeeze off technique has not been used much in the water distribution industry, because the distribution mains used therein, comprising mostly buried earthenware or PVC pipes, are not always suitable. Even if the squeeze off technique were to have been envisaged in the water distribution industry, it would have been considered impracticable for most applications due to the necessity to expose a fresh section of pipe each time the squeeze off clamp is applied. In any event, the present invention is not concerned with casual instances where a pipe might need to be constricted for some nusual reason and where the squeeze off technique finds its most frequent application. The invention is concerned with providing inexpensive simple valves where they are known to be required for normal, if infrequent, operation such as at junctions etc.
  • the present invention seeks to overcome the problems set out above by inserting into tj-re water distribution system at selected points one or,;" more valve members of cross-linked polyolefin pipe.
  • Cross-linked polyolefin pipe particularly when produced by peroxide cross- linking, has been found to be resilient and highly resistant to stress cracking. These properties can allow the cross-linked polyolefin pipe to be repeatedly subjected to a squeeze off flow inhibition technique at the same point, which current regulations do not permit for non-cross-linked polyolefin pipe.
  • a valve member for a fluid distribution system comprising an extruded cross-linked polyolefin pipe of less than three metres- in length and having at each end a connector for connection to another valve member or the system, the pipe being adapted to restrict or prevent flow through the pipe by application of an external pressure to the pipe in order resiliently to deform the pipe cross-section.
  • the invention Whilst the invention is primarily concerned with stopping fluid flow in a distribution main, so that fluid flow is either stopped or diverted, it may be sufficient in certain cases for the flow of fluid to be reduced rather than completely stopped.
  • a particular advantage of the method of the present invention is that fluid flow can be temporarily inhibited or stopped whilst the pipe is full of fluid, and there is no need to drain the system before the pipe can be blocked or stopped.
  • the invention provides a liquid, and especially a water, distribution pipe work system comprising valve members as described above.
  • the cross-linked polyolefin of the plastics pipe can comprise any suitable homopolymer or copolymer of ethylene, propylene, n-butylene, n-pentene or higher olefin homologues, and can include, if desired minor amounts of other comonomers such as, for example, dienes, vinyl esters and other ethylenically-unsaturated monomers .
  • the polyolefin of the pipe wall can be cross-linked by such techniques as radiation cross-linking, using a high energy electron beam or by silane cross-linking, using silane monomers which cross-link in the presence of moisture, but preferably the polyolefin material is cross-linked using a peroxide cross-linking method.
  • a peroxide cross-linking method a small quantity of a heat activatable peroxide, for example, di-tert-butyl peroxide (DTBP) , is incorporated into the polymer granules and fed into the barrel of an extruder.
  • DTBP di-tert-butyl peroxide
  • the peroxide breaks down forming free radicals which cross-link the polymer chains as the extruded polymer material leaves the extruder die.
  • Peroxide cross-linked polyolefms are particularly resistant to stress cracking and also give greatly improved resiliency, so that a pipe formed from a peroxide cross-linked extruded polyolefin can be repeatedly subjected to a squeeze off method at the same point without substantially weakening the pipe at that point .
  • the length of extruded cross-linked polyolefin pipe is connected to the fluid distribution system by the use of fusion fittings, and more preferably by the use of electrofusion fittings.
  • the length of cross-linked polyolefin pipe used is from 2 to 10 times the diameter of the pipe, more preferably from 4 to 8 times, for example around 6 times the diameter of the pipe.
  • Pipe diameters for water distribution mains generally vary from 63 to 315 mms .
  • the apparent improvement in strength obtain from using a relatively short length of cross-linked polyolefin pipe supported by electrofusion fittings can allow a thinner walled pipe to be specified to ease squeeze off and speed recovery rates, or can allow the use of lower density polyolefin material to provide increased flexibility for squeeze off operations.
  • the cross-linked polyolefin pipe has a wall thickness of from 2 to 30 mms.
  • MRS classification can be determined in accordance with ISO 1167, ISO 12162 and ISO TR 9080 (ISO 1167;1996: Plastic pipes for the transport of fluids - Determination of the resistance to internal pressure; ISO 12162 ,-1996: Thermoplastics materials for pipes and fittings for pressure applications - Classification and designation; ISO TR 9080; 1992: The determination of the long term hydrostatic strength for thermoplastics pipes materials) .
  • ISO TR 9080 which is accepted conventionally for judging and ranking thermoplastics pipe materials.
  • EVOH films can be applied, for example, to form gas barriers to prevent permeation of air into the water system.
  • a coloured film can be applied which, for example, can highlight the centre of the pipe section, thus indicating to the technician the optimum point for the application , of the squeeze off clamping tool.
  • Any suitable clamping device can be used in order to apply the localised external pressure to the pipe wall in order to resiliently deform the pipe cross section.
  • the device can clamp the pipe in a horizontal plane or a vertical plane, although where buried pipes are concerned, clamping in a vertical plane is usually preferred.
  • the clamping tool can be manually operated or hydraulically driven.
  • a feature of the invention is that ' the external pressure can be applied repeatedly to the same section of pipe wall without significantly degrading the physical properties of the cross-linked polyolefin pipe.
  • Valve members are preferably supplied as prefabricated assemblies from the factory so that they are suitable for connection into water distribution systems, for example, at street functions, where it is current practice to install a number of valves on site.
  • one connector can comprise a tee piece to which one end of the pipes of two other members as defined above are also connected. The assembly will have been welded within the factory environment and as such it is possible to ensure consistent quality of the joints.
  • a connector preferably an electrofusion coupler, is thus at each end of the three branches of the complete valve member assembly.
  • the flow stopping operation is a very simple matter.
  • a distribution team can carry a squeeze off clamping off tool and if a flow stop is required they can access the buried prefabricated assembly and apply the tool to the middle of the appropriate pipe section. After the desired work has been carried out, the clamping tool can be released and the pipe resiliently recovers to its former diameter, permitting renewed fluid flow.
  • Figure 1 shows an end elevation of a section of a cross-linked polyolefin pipe with a squeeze off clamping device disposed thereabout;
  • FIG. 2 shows a valve member in accordance with the present invention.
  • a clamping device illustrated generally at 1 is disposed about a cross-linked polyolefin pipe 2 the clamping device comprises a fixed jaw 3 mounted on legs 4 and a sljtlable jaw 5 which can move in a vertical plane and is . Also mounted on the legs 4 a frame member 6 spans the upper ends of the legs 4 and is rigidly attached thereto. Frame member 6 has a central screw threaded aperture 7 within which is situated a screw threaded thrust bar 8, having at its upper end a hand-operable cross piece 9. The thrust bar 8 can be turned by hand using the cross piece 9 and engages at its lower end 10 with the slidable jaw 5 of the clamping device 1.
  • the clamping device 1 is positioned on the cross -linked polyolefin pipe 2 and cross piece 9 turned by hand until the thrust bar 8 forces the slidable jaw 5 into contact with the cross-linked polyolefin pipe 2. Further turning of the cross piece 9 squeezes the cross- linked polyethylene pipe 2 between the jaws 3 and 5, flattening the cross section and blocking the flow of fluid through the pipe. Depth stops 11 are rotatable in the legs 4 and prevent the over-compression of the pipe 2.
  • pipe compression ie the final distance between jaws 3 and 5 is limited to not less than 80% of twice the wall thickness, and not less than 90% in the case of pipe diameters greater than 250mm.
  • FIG. 2 shows a valve member assembly 20 according to the present invention.
  • the term" “valve member” rather than “valve” is used herein because a separate squeeze off tool 1 is required to create an actuatable valve.
  • the assembly 20 of Figure 2 comprises three valve members 22,24,26, each sharing a common tee piece connector 28 at one end. At each other end of each member is disposed an electrofusion coupler 32,34,36.
  • Electrofusion coupling to cross-linked polyolefin pipe is possible, but there is a degree of prejudice, largely unfounded, that such coupling is difficult.
  • This is based on the fact that cross-linked polyethylene does not liquefy when heated and therefore does not, on the face of it, fuse and weld in the same way as uncross- 1inked polyethylene.
  • An advantage of the present invention is that these perceptions can be overcome by performing the electrofusion to cross-linked polyethylene in the factory and supplying the assembly as a complete unit. Of course, such an assembly would not be necessary where the entire pipe distribution system was cross - linked polyethylene, but that will not usually be the case, given the expense of cross-linking.
  • each coupler 32,34,36 can be connected to the usual uncross-linked polyethylene pipe of the water distribution system without any more difficulty or concern than any other junction or joint in the system.
  • the couplers 32,34,36 could even be provided with heating elements which are quite separate from the heating mechanism employed to connect the couplers to there respective valve member 22,24,26 so that the bond therebetween is not disturbed when the coupler is connected to the distribution system.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

L'invention concerne un élément de valve (22, 24, 26) destiné à inhiber temporairement le débit de liquide dans un conduit principal de distribution d'eau comprenant une longueur de tuyau en plastique. Le tuyau en plastique comprend une polyoléfine réticulée extrudée. Une pression externe est exercée sur une section localisée du tuyau en plastique par une bride de serrage, par exemple, afin de déformer élastiquement la section transversale du tuyau et inhiber le débit de liquide à l'intérieur.
PCT/GB2000/002123 1999-06-17 2000-06-14 Dispositif de restriction de debit pour tuyaux WO2000079175A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU55420/00A AU5542000A (en) 1999-06-17 2000-06-14 Flow restrictor for pipes

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9914033.7 1999-06-17
GB9914033A GB2351141A (en) 1999-06-17 1999-06-17 Pinch valve

Publications (1)

Publication Number Publication Date
WO2000079175A1 true WO2000079175A1 (fr) 2000-12-28

Family

ID=10855479

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2000/002123 WO2000079175A1 (fr) 1999-06-17 2000-06-14 Dispositif de restriction de debit pour tuyaux

Country Status (3)

Country Link
AU (1) AU5542000A (fr)
GB (1) GB2351141A (fr)
WO (1) WO2000079175A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115319831A (zh) * 2022-09-02 2022-11-11 威海市怡和橡塑制品有限公司 燃料油输送软管的现场维修工具组及维修方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4372528A (en) * 1981-07-06 1983-02-08 Red Valve Co., Inc. Pinch valve sleeve
JPH03255295A (ja) * 1990-03-01 1991-11-14 Sekisui Chem Co Ltd 止水用継手
DE4107098A1 (de) * 1991-03-06 1992-09-10 Ingo Windt Chlor-universalrohrquetscher
EP0872673A1 (fr) * 1997-04-18 1998-10-21 DEGAZ RT Délalföldi Gazszolgaltato Rt Robinet à tournant sphèrique avec boíte en polyéthylène

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB963679A (en) * 1961-01-30 1964-07-15 Godolphin Valves Ltd Fluid flow control valves
US3733046A (en) * 1971-03-22 1973-05-15 Resistoflex Corp Constrictable tube valve
GB2261049B (en) * 1991-09-26 1995-03-29 Amicon Ltd Pinch valve

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4372528A (en) * 1981-07-06 1983-02-08 Red Valve Co., Inc. Pinch valve sleeve
JPH03255295A (ja) * 1990-03-01 1991-11-14 Sekisui Chem Co Ltd 止水用継手
DE4107098A1 (de) * 1991-03-06 1992-09-10 Ingo Windt Chlor-universalrohrquetscher
EP0872673A1 (fr) * 1997-04-18 1998-10-21 DEGAZ RT Délalföldi Gazszolgaltato Rt Robinet à tournant sphèrique avec boíte en polyéthylène

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 016, no. 057 (M - 1210) 13 February 1992 (1992-02-13) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115319831A (zh) * 2022-09-02 2022-11-11 威海市怡和橡塑制品有限公司 燃料油输送软管的现场维修工具组及维修方法

Also Published As

Publication number Publication date
AU5542000A (en) 2001-01-09
GB9914033D0 (en) 1999-08-18
GB2351141A (en) 2000-12-20

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