EP0267234A4 - Dispositifs thermoretractables. - Google Patents

Dispositifs thermoretractables.

Info

Publication number
EP0267234A4
EP0267234A4 EP19870903086 EP87903086A EP0267234A4 EP 0267234 A4 EP0267234 A4 EP 0267234A4 EP 19870903086 EP19870903086 EP 19870903086 EP 87903086 A EP87903086 A EP 87903086A EP 0267234 A4 EP0267234 A4 EP 0267234A4
Authority
EP
European Patent Office
Prior art keywords
pipe
pipes
coupling member
wall thickness
heat
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Withdrawn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
EP19870903086
Other languages
German (de)
English (en)
Other versions
EP0267234A1 (fr
Inventor
George Raymond Langland
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.)
Raychem Corp
Original Assignee
Raychem Corp
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 Raychem Corp filed Critical Raychem Corp
Publication of EP0267234A1 publication Critical patent/EP0267234A1/fr
Publication of EP0267234A4 publication Critical patent/EP0267234A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/66—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by liberation of internal stresses, e.g. shrinking of one of the parts to be joined
    • B29C65/68—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by liberation of internal stresses, e.g. shrinking of one of the parts to be joined using auxiliary shrinkable elements
    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/3408—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising single particles, e.g. fillers or discontinuous fibre-reinforcements
    • B29C65/3412—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising single particles, e.g. fillers or discontinuous fibre-reinforcements comprising fillers
    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3484—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being non-metallic
    • B29C65/3488—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being non-metallic being an electrically conductive polymer
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1244—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue
    • B29C66/12441—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue being a single wall
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5221—Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B29C66/52291—Joining tubular articles involving the use of a socket said socket comprising a stop
    • B29C66/52293—Joining tubular articles involving the use of a socket said socket comprising a stop said stop being external
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B29C66/52298—Joining tubular articles involving the use of a socket said socket being composed by several elements
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/63—Internally supporting the article during joining
    • B29C66/636—Internally supporting the article during joining using a support which remains in the joined object
    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3484—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being non-metallic
    • B29C65/3492—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being non-metallic being carbon
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B29C66/52291—Joining tubular articles involving the use of a socket said socket comprising a stop
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined

Definitions

  • This invention relates to heat-recoverable devices and their use for repairing, reinforcing, joining or otherwise modifying a substrate.
  • heat-recoverable devices can be used to repair, reinforce, join or otherwise modify substrates of many kinds. It is also known that such devices can comprise a heating element which is composed of a conductive polymer and which, when connected to a suitable power source, will generate heat and cause recovery of the device.
  • the heating element can itself be heat-recoverable, and/or it can be secured to a recoverable article and be such that it does not prevent recovery of the article.
  • U.S. Patents Nos. 4,085,286, 4,177,376, 4,177,446, 4,421,582, 4,570,055 and 4,575,618 and to copending commonly assigned U.S. patent applications Serial Nos.
  • the invention provides a radially heat-shrinkable hollow member, preferably a cylindrical coupling member which
  • (1) is composed of a conductive polymer
  • (2) comprises at least two heat-shrinkable end sections, and at least two heat-shrinkable intermediate sections each of which is adjacent to a heat-shrinkable end section, and
  • the (3) can be caused to shrink by passing current longitudinally therethrough; wherein at least one of the end sections has a wall thickness which is at least 1.05 times the wall thickness of the intermediate section adjacent thereto.
  • the increased wall thickness results in the end section(s) having a lower resistance, and this (together with other factors such as the greater heat loss from the end sections) results in the generation of higher temperatures under the intermediate sections than under the end sections(s), so that although the end sections are caused to shrink, overheating of the thermoplastic pipe is avoided.
  • the end sections are preferably identical to each other, but can be different.
  • the intermediate sections can be joined directly to each other, so that there is then a single intermediate section which is notionally divided into two (or more) parts which behave in the same way if the coupling member is used to join like substrates but which behave in different ways if the coupling member is used to join unlike substrates.
  • the intermediate sections can be joined to each other through a center section, for example a center section which has a plurality of circumferential ribs on the interior surface thereof in order to provide improved coupling to the substrates.
  • the heat-shrinkable members of the present invention are particularly useful in the form of cylindrical coupling members, especially for joining pipes, and the invention will be chiefly described by reference to such use. However, they can also be used for repairing or reinforcing or otherwise modifying a substrate, for example for adding a branch pipe to an existing pipe.
  • the invention provides a method of joining two pipes which comprises placing the ends of the pipes inside a cylindrical coupling member as defined above, and passing current tnrough the coupling member so that it is heated and shrinks around the pipes.
  • each of the pipes is composed of a thermoplastic material and the conditions of tne method are such that one of the intermediate sections becomes fused to one of the pipes and the end section adjacent thereto shrinks into compressive contact with that pipe but does not become fused tnereto, and the other intermediate section becomes fused to the other pipe and the end section adjacent thereto shrinks into compressive contact with the other pipe but does not become fused thereto.
  • one of the pipes is composed of a metal and the other pipe is composed of a thermoplastic material
  • the conditions of the method are such that one of the intermediate sections becomes fused to the thermoplastic pipe and the end section adjacent thereto shrinks into compressive contact with the thermoplastic pipe but does not become fused thereto, and the other intermediate section and the other end section shrink into compressive contact with the metal pipe.
  • at least part of the surface of the thermoplastic pipe which becomes fused to the coupling member is heated to a temperature at which the thermoplastic material is completely melted, and the maximum temperature reached by at least part of the surface of the thermoplastic pipe which is brought into compressive contact with the end section is less than the temperature at which the thermoplastic material begins to melt.
  • Figure 1 is a longitudinal cross-section through an unexpanded blank for a coupling member
  • Figure 2 is a transverse cross-section taken on line II-II of Figure 1;
  • Figure 3 shows an assembly for joining two pipes by means of a coupling member made by radial expansion of a blank as shown in Figures 1 and 2.
  • Figure 4 is a transverse cross-section through a wrap-raround repair sleeve of the invention placed around a pipe;
  • Figure 5 is a longitudinal cross-section taken on V-V of Figure 4 (but not showing the pipe).
  • Figure 6 is a plan view of another coupling member of the invention.
  • the invention is particularly useful when the coupling member shrinks into direct physical contact with the substrate(s) , especially when at least one of the substrates is composed of (or has at least an outer surface composed of) a thermoplastic material, and there is fusion between at least one of the intermediate secrions and the thermoplastic material.
  • fusion is used herein to mean that sufficient molecular compatibility exists between the element and the substrate outer surface that a bond forms which will provide mechanical performance equal to or greater than that of the substrate. This may be through viscoelas ic contact as defined by J.N.
  • the inven ⁇ tion can also be used when a heat-responsive insert of some kind, eg. a curable polymeric insert, a hot melt adhesive, a mastic or a solder is placed between all or part of the heat-shrinkable member and the substrate.
  • a heat-responsive insert of some kind eg. a curable polymeric insert, a hot melt adhesive, a mastic or a solder is placed between all or part of the heat-shrinkable member and the substrate.
  • the maximum temperature reached by the surface of the substrate underneath the end section of the coupling member is less than the temperature at which the thermoplastic material begins to melt (defined herein as the temperature at which a differential scanning calorimeter plot for the material, measured in accordance with ASTM, first departs from a straight line); and it is also preferred that at least part of the surface of the substrate underneath the intermediate section is heated to a temperature above the temperature at which the thermoplastic material is completely melted (defined herein as the peak temperature on the same plot).
  • the thermoplastic material preferably comprises an organic polymer, eg.
  • a crystalline polymer which is preferably not cross-linked, but can be cross-linked.
  • the composition can consist essentially of such a polymer and, if desired, conventional stabilizers for the polymer, or it can also contain one or more fillers, eg. in amount up to 20%, preferably not more than 10%, by weight.
  • Particularly suitable polymers are polymers of one or more ethylenically unsaturated monomers, eg. polyolefins, including in particular low, medium and high density polyethylenes and polypropylene, and polyvinyl chloride.
  • Particularly useful substrates are pipes, particularly pipes which are composed of the thermoplastic material, especially pipes as defined in ASTM D-2513 and D-3350; such pipes are suitable for example for transporting natural gas or water.
  • the heat-shrinkable member is preferably composed of a conductive polymer which is compatible with the thermoplastic material of the substrate, the organic polymers in the conductive polymer and the thermoplastic material preferably comprising at least 80%, particularly at least 90%, of the same repeating units.
  • Particularly suitable conductive polymers are based on very high molecular weight polymers, particularly a sintered mixture of an organic polymer, especially ultra high molecular weight polyethylene (UHMWPE) , and a conductive filler, particularly carbon black.
  • UHMWPE ultra high molecular weight polyethylene
  • the coupling member is usually monolithic, but can comprise first and second parts which are secured as a "wrap-around" around a substrate (as for example in Figures 4 and 5), in which case only part of the member need be heat-shrinkable.
  • end section is used herein to denote a section which is nearer to an open end of the member than the adjacent intermediate section; the end section can include the open end, but does not necessarily do so - for example the open end need not necessarily be heat shrinkable.
  • the term "compressive contact” is used to indicate that the member, after shrinkage, exerts hoop stress on the pipe.
  • the hoop stress is sufficient to create a circumferential depression around a plastic pipe. It is theorized that the presence of the hoop stress helps to combat the effects of cold flow of the thermoplastic substrate which may take place over an extended time. In addition, this feature assists in satisfactorily spreading flexural and other stresses over the coupling as a whole.
  • the reduction in wall thickness which is characteristic of the heat-shrinkable members of this invention can take place abruptly, in which case it is simple to identify the end and intermediate sections. It is preferred, however, that the reduction in wall thickness should be gradual.
  • the wall thickness can decrease gradually from each open end towards the center of the member, there being optionally a center section which lies between the intermediate sections and in which there is no such decrease in wall thickness.
  • the junction between the end and intermediate sections is defined herein as the point at which the wall thickness is equal to the.average of the maximum and minimum wall thicknesses of the member.
  • the wall thickness of the end section(s) is at least 1.05 times, preferably at least 1.1 times, e.g. 1.1 to 1.4 times, the wall thickness of the adjacent intermediate section; and the wall thicknesses referred to are the maximum wall thicknesses in the end and intermediate sections respectively.
  • the con ⁇ ditions are preferably such that the ends of the pipes are butt-welded to each other. Particularly under these cir ⁇ cumstances, it is preferred that a support member be placed' within the pipes to ensure that molten pipe material does not drip into the interior of the pipe.
  • Figures 1 and 2 show an unexpanded blank which can be converted into a coupling member of the invention by a process which comprises radial expansion.
  • the blank 1 is composed of a blend of carbon black and UHMWPE which has been ram-extruded as a cylinder and then machined into the shape shown, which comprises a center section 11 of generally uniform inner and outer diameter with a plurality of small ribs 111 on its inner surface, and two tapered end sections 12 and 13 having a constant outer diameter and an inner diameter which increases from the end adjacent the center section to the open end.
  • Figure 3 shows a coupling member 2 made by radial expan ⁇ sion of a blank as shown in Figures 1 and 2 (to a generally uniform inner diameter which is slightly larger than the pipes to be joined thereby) , followed by attachment of electrodes 24 and 25.
  • the electrodes are shaped and posi ⁇ tioned so as to provide the desired distribution of heat within the coupling member (and hence also the pipes) when the electrodes are connected to a suitable power supply.
  • pipes 3 and 4 to be joined by coupling member 2, and support member 5 which helps to keep the pipes in position and to prevent excessive deformation of the pipes during the coupling operation.
  • Figures 4 and 5 show a wrap-around heat-shrinkable repair sleeve for repairing a crack 31 in a plastic pipe 3 (shown in Figure 4 but not in Figure 5).
  • the repair sleeve comprises longitudinal electrodes 24 and 25 and hemicy- lindrical parts 26 and 27 which are composed of heat- shrinkable conductive polymer and which are secured to each other around the pipe by means of snap-fittings 261 and 271.
  • Part 26 comprises relatively thick end sections 262 and 263 and relatively thin center section 261 which covers the crack in the pipe.
  • Part 27 is of uniform wall thickness.
  • the sleeve shrinks into contact with the pipe, the center section 261 reaching a higher temperature than the rest of the sleeve and fusing to the pipe 3, so as to seal the crack 31, and the rest of the sleeve shrinking into compressive contact with the pipe but not becoming fused thereto.
  • Figure 6 shows a coupling member 2 which comprises a first heat-shrinkable part 27 of relatively large diameter and wall thickness, a second heat-shrinkable part 26 of relatively small diameter and wall thickness, and axially spaced circumferential electrodes 241, 242 and 243.
  • Recovery of all or part of the member can be effected by connecting a suitable power supply to an appropriate pair of electrodes.
  • a blank for a coupling member was made in the following way.
  • Carbon black (Ketjenblack EC 300 available from Akzo
  • Hoechst about 150 parts by weight, in a Henschel blender.
  • the resulting blend was ram-extruded at about 255°C into a rod having a diameter of about 3.26 inch. A length cut from the rod was then machined into a blank as shown in
  • each end section had a length of 1 inch, a uniform outer surface having a constant diameter of 2.59 inch and an inner surface which tapers uniformly at an angle of 5° from a diameter at the end adjacent the center section of 2.11 inch to a diameter at the other end of 1.94 inch.
  • the blank was then heated to about 135°C, expanded by means of a tapered mandrel to a uniform internal diameter of about 2.55 inch, and cooled in water at 20°C for 15 minutes before the mandrel was removed. Electrodes were then painted on the ends of the expanded blank, using a silver- containing paint (Electrodag 504 available from Acheson Colloids Co.), to give a coupling member as shown in Figure 3, each electrode extending 0.25 inch down the length of the member and 0.12 down the diameter of the member.
  • a silver- containing paint Electrodes were then painted on the ends of the expanded blank, using a silver- containing paint (Electrodag 504 available from Acheson Colloids Co.), to give a coupling member as shown in Figure 3, each electrode extending 0.25 inch down the length of the member and 0.12 down the diameter of the member.
  • the coupling member was used to join together two pipes, available from Phillips as Driscopipe, 6500 series, each pipe having an inner diameter of 1.94 inch and an outer diameter of 2.375 inch and being composed of polyethylene.
  • the pipes were positioned within the coupler over a poly ⁇ meric coupling member composed of " ⁇ ltem", available from General Electric.
  • the electrodes were connected to a 40 volt AC power supply, and after about 2.5 minutes the coupling member had shrunk into close and conforming contact with the pipes. The coupling member was disconnected from the power supply and allowed to cool.

Abstract

Des dispositifs polymères conductifs creux et thermorétractables, en particulier des éléments de liaison (2) pour raccorder des tuyaux polymères (3, 4) comportent des parties extrêmes (12, 13) ayant une plus forte épaisseur de paroi, de sorte que lorsqu'on fait passer un courant à travers le dispositif, les parties extrêmes sont chauffées à une température inférieure. De cette manière, on évite de surchauffer (et par conséquent d'affaiblir) la partie du tuyau entourée par la partie extrême du dispositif.
EP19870903086 1986-04-18 1987-04-09 Dispositifs thermoretractables. Withdrawn EP0267234A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US85380586A 1986-04-18 1986-04-18
US853805 1986-04-18

Publications (2)

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EP0267234A1 EP0267234A1 (fr) 1988-05-18
EP0267234A4 true EP0267234A4 (fr) 1989-07-11

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EP19870903086 Withdrawn EP0267234A4 (fr) 1986-04-18 1987-04-09 Dispositifs thermoretractables.

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EP (1) EP0267234A4 (fr)
JP (1) JPS63503158A (fr)
AU (1) AU7304687A (fr)
WO (1) WO1987006182A1 (fr)

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FR2648077B1 (fr) * 1989-06-09 1991-10-18 Boulet D Auria Terlizzi Procede de raccordement de deux elements tubulaires en matiere plastique par electro-soudage et raccord d'electro-soudage pour la mise en oeuvre de ce procede
FR2648078B1 (fr) * 1989-06-09 1997-05-09 Boulet D Auria Terlizzi Element d'electro-soudage en matiere plastique conductrice et raccord d'electro-soudage pour elements en matiere plastique realise a l'aide de celui-ci
GB8926294D0 (en) * 1989-11-21 1990-01-10 British Gas Plc Method of jointing hollow members by fusion
GB9122511D0 (en) * 1991-10-23 1991-12-04 Raychem Sa Nv Heat recoverable article
WO1993019926A1 (fr) * 1992-03-30 1993-10-14 United Technologies Corporation Element chauffant pour soudage thermoplastique
WO1994019173A2 (fr) * 1993-02-26 1994-09-01 Raychem Corporation Procedes et dispositifs servant a joindre des articles
GB2325501A (en) 1997-05-22 1998-11-25 Uponor Ltd Heat fusion fitting
US7337486B2 (en) 2006-04-25 2008-03-04 Leatherman Tool Group, Inc. Hand tool

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DE2254232A1 (de) * 1971-11-19 1973-05-24 Foerderung Forschung Gmbh Stromdurchflossener heizleiter mit axial unterschiedlicher leistungsverteilung, verfahren zu dessen herstellung und vorrichtung zur ausfuehrung des verfahrens
GB2083406A (en) * 1980-08-29 1982-03-24 Sturm Werner Thermoplastic welding sleeve and a mold assembly for making same
EP0157640A2 (fr) * 1984-04-04 1985-10-09 RAYCHEM CORPORATION (a Delaware corporation) Article à reprise thermique en polymères conductrices
EP0251482A2 (fr) * 1986-05-27 1988-01-07 RAYCHEM CORPORATION (a California corporation) Raccord à reprise thermique

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US4017715A (en) * 1975-08-04 1977-04-12 Raychem Corporation Temperature overshoot heater
US4421582A (en) * 1975-08-04 1983-12-20 Raychem Corporation Self-heating article with deformable electrodes
CA1197963A (fr) * 1981-07-22 1985-12-17 Michito Matsumoto Dispositif et methode de chauffe pour tubes thermoretrecissables
JPS58212915A (ja) * 1982-06-04 1983-12-10 Sumitomo Electric Ind Ltd 熱収縮チユ−ブの加熱方法及び装置
CH658426A5 (de) * 1983-02-04 1986-11-14 Fischer Ag Georg Verfahren zum verschweissen von leitungselementen aus thermoplastischem material und eine dafuer geeignete einrichtung.
US4570055A (en) * 1984-05-07 1986-02-11 Raychem Corporation Electrically heat-recoverable assembly
US4575618A (en) * 1984-07-25 1986-03-11 Raychem Corporation Switch unit for use with heat-recoverable articles

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
DE2254232A1 (de) * 1971-11-19 1973-05-24 Foerderung Forschung Gmbh Stromdurchflossener heizleiter mit axial unterschiedlicher leistungsverteilung, verfahren zu dessen herstellung und vorrichtung zur ausfuehrung des verfahrens
GB2083406A (en) * 1980-08-29 1982-03-24 Sturm Werner Thermoplastic welding sleeve and a mold assembly for making same
EP0157640A2 (fr) * 1984-04-04 1985-10-09 RAYCHEM CORPORATION (a Delaware corporation) Article à reprise thermique en polymères conductrices
EP0251482A2 (fr) * 1986-05-27 1988-01-07 RAYCHEM CORPORATION (a California corporation) Raccord à reprise thermique

Non-Patent Citations (1)

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See also references of WO8706182A1 *

Also Published As

Publication number Publication date
AU7304687A (en) 1987-11-09
JPS63503158A (ja) 1988-11-17
WO1987006182A1 (fr) 1987-10-22
EP0267234A1 (fr) 1988-05-18

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