GB2327992A - Sheet for electrofusion fitting - Google Patents

Sheet for electrofusion fitting Download PDF

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Publication number
GB2327992A
GB2327992A GB9716645A GB9716645A GB2327992A GB 2327992 A GB2327992 A GB 2327992A GB 9716645 A GB9716645 A GB 9716645A GB 9716645 A GB9716645 A GB 9716645A GB 2327992 A GB2327992 A GB 2327992A
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GB
United Kingdom
Prior art keywords
sheet
sheet element
thermoplastics
jointing
fitting
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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
GB9716645A
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GB9716645D0 (en
GB2327992B (en
Inventor
Colin George Burley
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Individual
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Individual
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Filing date
Publication date
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Priority to GB9716645A priority Critical patent/GB2327992B/en
Publication of GB9716645D0 publication Critical patent/GB9716645D0/en
Publication of GB2327992A publication Critical patent/GB2327992A/en
Application granted granted Critical
Publication of GB2327992B publication Critical patent/GB2327992B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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
    • 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
    • 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
    • B29C65/342—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 at least a single wire, e.g. in the form of a winding
    • B29C65/3428—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 at least a single wire, e.g. in the form of a winding said at least a single wire having a waveform, e.g. a sinusoidal form
    • 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
    • B29C65/3476—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 metallic
    • B29C65/348—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 metallic with a polymer coating
    • 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
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/4805—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding characterised by the type of adhesives
    • B29C65/481—Non-reactive adhesives, e.g. physically hardening adhesives
    • B29C65/4815—Hot melt adhesives, e.g. thermoplastic adhesives
    • 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
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/50—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like
    • B29C65/5057—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like positioned between the surfaces to be joined
    • 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
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • 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
    • B29C66/70—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
    • B29C66/73—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/739—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • B29C66/73921—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 intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
    • 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
    • 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
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • 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
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

The sheet 6 is a rectangular piece of electrically insulating flexible thermoplastics with an electrical circuit path 2 of sinuous form conducting material, the form having its peaks/troughs adjacent to side edges and with parallel paths between the peaks/troughs. The path 2 can be wire laid onto the sheet or sheet metal stamping. The sheet is then formed into a cylindrical shape which can then be placed on a core and moulded into a fitting or placed into a sleeve of thermoplastics material and made into a fitting. The edges of the sheet 6 can be castellated and the wires following the peaks and troughs to provide an interlocking formation, eliminating a potential leakage path. The pre form sheet can either be of similar thermoplastic material as the body of the fitting a and remain as an integral part of the fitting after manufacture, or can be of a dissimilar material of a higher melt for reuse after the manufacture of the fitting.

Description

A method for the manufacture of electrofusion fittings This invention relates to a method of manufacturing electroflision fittings.
Electrofusion fittings are now commonly used as a method of jointing polyolefine pipes, typically polyethylene ( PE ) (for gas, water, sewerage and similar service applications ) and polypropylene (PP) ( typically for process plant ). Electrofusion fittings comprise of a moulded or fabricated PE or PP body with an embedded electrical resistance wire. The joint is made by inserting the pipes into the fitting, pushing the ends together and energising the resistance wire, locally heating and melting the mating surfaces of the fitting and pipes. Subsequent cooling bonds the two surfaces together.
Although a number of methods of embedding the wire are employed the two most common are as follows, Firstly, the selected wire is coated in PE or PP of similar grade to the fitting. The coated wire is wound onto a core and loaded into a mould cavity in an injection moulding machine. PE or PP is injected into the cavity forming the body of the fitting and bonding the coated wire to the body making an homogenous fitting.
Secondly, a thin cylindrical PE or PP grooved pre-form is moulded. The selected wire is wound onto the pre-form. The wound pre-form is loaded into the mould cavity and the process as described above is carried out.
Other techniques exist, however all involve winding the wire onto a cylindrical core. As the diameter of the fittings increases, these techniques employ larger and more expensive cores and winders.
According to the present invention there is provided a method of manufacturing electrofusion fittings comprising a nat sheet onto which the conducting wire is laid. The sheet is then formed into a cylindrical shape making a pre-form, which can then be placed on a core and injection moulded in the conventional manner, or placed into a sleeve of polymer material and made into a fitting.
A specific embodiment of the invention will now be described by way of an example with reference to the accompanying drawings in which Fig. 1 shows the complete electrofusion fitting with the wire and pre form embedded into the fitting.
Fig. 2a shows the polymeric sheet with the wire laid onto it.
Fig. 2b shows the sheet formed into a cylindrical shape inside the body of the electrofusion fitting.
Fig. 3 shows an improvement to the design of the sheet with castellated edges to eliminate potential leakage path.
Fig. 4 shows the wire laid onto the castellated sheet.
Referring to Fig. 1, the electrofusion fitting comprises of a pre-form ( 1 ) made of a sheet of polymeric material with wire ( 2 ) laid onto it. The sheet from which the pre-form (1) is made is of similar material to the body ( 3 ) of the fitting. . The sheet from which the preform (1) is made is then formed into a cylindrical shape and the body ( 3 ) of the fitting is then moulded to form the electrofusion fitting. The wires are connected through terminal connections ( 4 ) on the body ( 3 ) of the fitting.
Fig. 2a shows the detail of the pre-form sheet ( 1 ) and wire ( 2 ) with terminations ( 5).
Fig. 2b shows the pre-form sheet 1 with the embedded wire, not shown, formed into a cylindrical shape, its width being equivalent to the internal circumference of the body ( 3).
Fig. 3 shows an improved design of pre-form sheet ( 6 ) of polymeric material, performing the same functions as item (1), Figs 2a and 2b, where the edges ( 7 ) are shaped to form an interlock, for example a castellated shape, when formed into a cylinder.
Fig 4 shows the wires ( 2 ) and terminations ( 5 ) laid onto the castellated pre form sheet (6) which when formed into a cylinder would eliminate the potential leakage path.
Referring again to Figs 2 and 4 , alternatives to laying the wire ( 2 ) onto the pre-form sheet ( 1 ) is to stamp the circuit layout from a sheet of conducting material, or employ any suitable means of laying down the conducting material.
An alternative method of manufacture of the electrofusion fitting is shown in fio. 5. The pre-form sheet (1) of polymeric material and wire ( 2 ) are formed into a cylindrical shape such that the edges overlap to form a circumference smaller than the bore of the sleeve ( 8). The sleeve ( 8 ) can be made from extruded pipe or moulded to the hollow cylindrical shape. The pre-form sheet (1 ) and wire ( 2 ) are now inserted into the sleeve (8). An expanding core ( not shown) is also inserted into the bore of the sleeve ( 8 ) and expanded against the previously inserted pre-form sheet (I) and wire ( 2). Intimate contact is then ensured between the pre-form sheet (1) and wire ( 2 ) and the bore of the sleeve ( 8 ). The wire ( 2 ) is then energised to create heat so that the pre-form sheet (I ) is bonded to the inside of the sleeve ( 8). On subsequent cooling the expanding core ( not shown ) is removed leaving the electrofusion fittin(y ready for use.
Referring to Figs I and 5 an alternative method of manufacture is to lay the wire ( 2 ) onto a pre-form sheet (1) of dissimilar material having a higher melt temperature than the material of the body ( 3 ). Thus after making the fitting as described above the preform sheet is removed for re-use leaving the wire embedded in the body ( 3).

Claims (15)

1. A sheet element for electrofusion of thermoplastics pipes or tubes comprising a generally rectangular sheet of flexible thermoplastics electrically insulating material having orthogonal axes in the plane of the sheet respectively parallel to the adjacent side edges of the insulating material sheet wherein the sheet element includes an electrical circuit path of electrically conducting material of sinuously extending form with alternating peaks and troughs respectively adjacent to opposite sides of one pair of opposite parallel sides of the insulating material sheet and wherein adjacent parts ofthe said current path, extending across the insulating material sheet from one side of the said one pair of opposite parallel sides to the other side, are mutually generally parallel.
2. A sheet element as claimed in claim 1 wherein the flexible thermoplastics material of the said sheet is polyethylene or polypropylene.
3. A sheet element for electrofusion of thermoplastics pipes or tubes as claimed in claim 1 formed such that said opposite sides of the said one pair of opposite sides of the insulating material sheet are able to be mutually interlocked.
4. A sheet element as claimed in claim 3 wherein the interlocking is provided by mutually interlocking formations of the said one pair of opposite sides.
5. A sheet element as claimed in claim 4 wherein the mutually interlocking formations are castellated formations.
6. A sheet element as claimed in claim 5 wherein the castellated formations of the siad opposite sides are of opposite phase, so that a peak of one side corresponds to a trough of the other side.
7. A sheet element as claimed in claim 6 wherein alternate peaks of said circuit path on each of the said one side and respectively said opposite side of the insulating material sheet extend into adjacent castellations on each respective side.
8. A sheet element as claimed in any preceding claim wherein the electrical circuit path is provided by a conducting wire laid onto the thermoplastics sheet.
9. A sheet element as claimed in any of the claims 1 to 7 wherein the electrical circuit path is provided by a sheet metal stamping layed onto the thermoplastics sheet.
10. A sheet element as claimed in any ofthe claims 1 to 9 wherein the thermoplastic sheet is formed of a material which has a higher melt temperature than that of the pipe or tube grade polyethylene or polypropylene.
11. A method of making a joint fitting for joining pipes or tubes by electrofusion comprising a jointing sheet element as claimed in any ofthe claims 1 to 10 and integrally moulding at least the electrically conducting part of the jointing sheet element with the joint fitting part.
12. A method of making a joint fitting for jointing pipes and tubes by electrofusion, comprising, providing a preformed joint fitting of thermoplastics material and a jointing sheet element as claimed in claim 9; placing the jointing sheet element circumferentially around the internal face of a coupling region of the preformed joint fitting with the electrically conducting part of the jointing sheet element adjacent the said internal face; introducing a radially expandable cylindrical mandrel inside the jointing sheet element and fitting end; radially expanding the mandrel to urge the jointing sheet element and fitting together; passing an electric energising current through the electrical circuit path to raise its temperature above that of the melt temperature of the pipe or tube joint fitting but not so high as to reach the melt temperature of the jointing sheet element thermoplastics material, so as to allow the circuit path material to mould into the material of the joint fitting, allowing the heated thermoplastics to cool below its melt temperature; and removing the insulating material sheet for reuse.
13. An electrofusion joint incorporating a sheet element as claimed in any of the claims 1 to 9.
14. An electrofusion joint fitting formed according to claims 10 or 11.
15. An electrofusion joint formed substantially as hereibefore described and as illustrated in figures 1 to 5 of the accompanying drawings.
15. A sheet element as claimed in any ofthe claims 1 to 9 and substantially as herein described and as illustrated in figures 1, 2a and 2b or figs 3 and 4 or fig 5 of the accompanying drawings.
16. An electrofusion joint fitting substantially as herein described and as illustrated in figures 1 to 5 of the accompanying drawings.
17. An electrofusion joint formed substantially as herein described and as illustrated in figures 1 to 5 of the accompanying drawings.
Amendments to the claims have been filed as follows 1. A sheet element for electrofusion of thermoplastics pipes or tubes comprising a generally rectangular sheet of flexible thermoplastics electrically insulating material having orthogonal axes in the plane of the sheet respectively parallel to the adjacent side edges of the insulating material sheet wherein the sheet element includes an electrical circuit path of electrically conducting material of sinuously extending form with alternating peaks and troughs respectively adjacent to opposite sides of one pair of opposite parallel sides of the insulating material sheet and wherein adjacent parts of the said current path, extending accross the insulating material sheet from one side of the said one pair of opposite parallel sides to the other side, are mutually generally parallel and wherein the said opposite sides of the said one pair of opposite sides of the insulating material sheet have formations which are able to be mutually interlocked.
2. A sheet element as claimed in claim 1 wherein the flexible thermoplastics material of the said sheet is polyethylene or polypropylene.
3. A sheet element as claimed in any preceding claim wherein the mutually interlocking formations are castelleted formations.
4. A sheet element as claimed in any preceding claim wherein the castellated formations of the said opposite sides are of opposite phase, so that a peak of one side corresponds to a trough of the other side.
5. A sheet element as claimed in claims 3 or 4 wherein alternate castellated formations or peaks of said circuit path on each of the said one side and respectively said opposite side of the insulating material sheet extend into adjacent castellations on each respective side.
6. A sheet element as claimed in any preceding claim wherein the electrical circuit path is provided by a conducting wire laid onto the thermoplastics sheet.
7. A sheet element as claimed in any of claims 1 to 5 wherein the electrical circuit path is provided by a sheet metal stamping layed onto the thermoplastics sheet.
8. A sheet element as claimed in any preceding claim wherein the thermoplastics sheet is formed of a material which has a higher melt temperature than that of pipe or tube grade polyethylene or polypropylene.
9. A method of making a joint fitting for joining pipes or tubes by electrofusion comprising: providing a jointing sheet element as claimed in any preceding claim and integrally moulding at least the electrically conducting part of the jointing sheet element with the joint fitting part.
10. A method of making a joint fitting for jointing pipes and tubes by electrofusion, comprising: providing a preformed joint fitting of thermoplastics material and a jointing sheet element as claimed in claim 8; placing the jointing sheet element circumferentially around the internal face of a coupling region of the preformed joint fitting with the electrically conducting part of the jointing sheet element adjacent the said internal face; introducing a radially expandable cylindrical mandrel inside the jointing sheet element and fitting end; radially expanding the mandrel to urge the jointing sheet element and fitting together; passing an electric energising current through the electrical circuit path to raise its temperature above that of the melt temperature of the pipe or tube joint fitting but not so high as to reach the melt temperature of the jointing sheet element thermoplastics material, so as to allow the circuit path material to mould into the material of the joint fitting, allowing the heated thermoplastics to cool below its melt temperature; and removing the insulating material sheet for reuse.
11. An electrofusion joint incorporating a sheet element as claimed in any of claims 1 to 8.
12. An electrofusion joint fitting formed according to claims 9 or 10.
13. A sheet element as claimed in any of claims 1-8 and substantially as herein described and as illustrated in figures 1, 2a, and 2b or figs 3 and 4 or fig 5 of the accompanying drawings.
14. An electrofusion joint fiting substantially as hereibefore described and as illustrated in figures 1 to 5 of the accompanying drawings.
GB9716645A 1997-08-07 1997-08-07 A sheet element for electrofusion of thermoplastics pipes and tubes Expired - Fee Related GB2327992B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9716645A GB2327992B (en) 1997-08-07 1997-08-07 A sheet element for electrofusion of thermoplastics pipes and tubes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9716645A GB2327992B (en) 1997-08-07 1997-08-07 A sheet element for electrofusion of thermoplastics pipes and tubes

Publications (3)

Publication Number Publication Date
GB9716645D0 GB9716645D0 (en) 1997-10-15
GB2327992A true GB2327992A (en) 1999-02-10
GB2327992B GB2327992B (en) 2002-07-24

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GB9716645A Expired - Fee Related GB2327992B (en) 1997-08-07 1997-08-07 A sheet element for electrofusion of thermoplastics pipes and tubes

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2868007A1 (en) * 2004-03-25 2005-09-30 Innoge Pe Ind Sam Sa Monegasqu Insert, for electric welding of joints and pipes, has a thermo-fusible insulating film substrate covering an electrical conductive circuit at least partially
WO2010121339A1 (en) * 2009-04-22 2010-10-28 Juan Rukavina Mikusic Method for the highly-thick thermal coating of joints by using electrofusion in pipes used for conducting fluids, made of steel tubes externally coated with polyolefins
WO2016156073A1 (en) * 2015-03-27 2016-10-06 Bayerische Motoren Werke Aktiengesellschaft Resistance element, component arrangement and method for resistance welding of thermoplastic components, and component assembly
WO2018185731A1 (en) * 2017-04-07 2018-10-11 BRIE, Sebastián José Method for embedding meshes used as heating agents in the fusion welding of polyolefin materials used in the manufacture of parts
LU100865B1 (en) * 2018-07-03 2020-01-07 Aliaxis R&D Sas Coupling element, coupling assembly with such a coupling element and method of coupling a first substrate to such a coupling element

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GB1408779A (en) * 1971-12-03 1975-10-08 Fischer Ag Georg Method of and apparatus for welding a saddle-shaped plastics member to an elongate plastics member
EP0622171A1 (en) * 1993-04-27 1994-11-02 Streng Plastic AG Heating device for surface welding of thermoplastics and method for producing it
GB2296059A (en) * 1994-11-28 1996-06-19 Fischer Georg Rohrleitung Welding together two corrugated plastics tubes and joint formed thereby

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Publication number Priority date Publication date Assignee Title
GB1408779A (en) * 1971-12-03 1975-10-08 Fischer Ag Georg Method of and apparatus for welding a saddle-shaped plastics member to an elongate plastics member
EP0622171A1 (en) * 1993-04-27 1994-11-02 Streng Plastic AG Heating device for surface welding of thermoplastics and method for producing it
GB2296059A (en) * 1994-11-28 1996-06-19 Fischer Georg Rohrleitung Welding together two corrugated plastics tubes and joint formed thereby

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2868007A1 (en) * 2004-03-25 2005-09-30 Innoge Pe Ind Sam Sa Monegasqu Insert, for electric welding of joints and pipes, has a thermo-fusible insulating film substrate covering an electrical conductive circuit at least partially
WO2010121339A1 (en) * 2009-04-22 2010-10-28 Juan Rukavina Mikusic Method for the highly-thick thermal coating of joints by using electrofusion in pipes used for conducting fluids, made of steel tubes externally coated with polyolefins
US9080702B2 (en) 2009-04-22 2015-07-14 Juan Rukavina Mikusic Method for the highly-thick thermal coating of joints by using electrofusion in pipes used for conducting fluids, made of steel tubes externally coated with polyolefins
WO2016156073A1 (en) * 2015-03-27 2016-10-06 Bayerische Motoren Werke Aktiengesellschaft Resistance element, component arrangement and method for resistance welding of thermoplastic components, and component assembly
WO2018185731A1 (en) * 2017-04-07 2018-10-11 BRIE, Sebastián José Method for embedding meshes used as heating agents in the fusion welding of polyolefin materials used in the manufacture of parts
LU100865B1 (en) * 2018-07-03 2020-01-07 Aliaxis R&D Sas Coupling element, coupling assembly with such a coupling element and method of coupling a first substrate to such a coupling element
WO2020007921A1 (en) 2018-07-03 2020-01-09 Aliaxis R&D S.A.S Coupling element, coupling assembly with such a coupling element and method of coupling a first substrate to such a coupling element
WO2020007924A1 (en) 2018-07-03 2020-01-09 Aliaxis R&D S.A.S Coupling element, coupling assembly with such a coupling element and method of coupling a first substrate to such a coupling element
AU2019297036B2 (en) * 2018-07-03 2022-08-04 Aliaxis Research & Technology Coupling element, coupling assembly with such a coupling element and method of coupling a first substrate to such a coupling element

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GB9716645D0 (en) 1997-10-15
GB2327992B (en) 2002-07-24

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