GB2137298A - Branch pipe fitting - Google Patents

Branch pipe fitting Download PDF

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Publication number
GB2137298A
GB2137298A GB08308800A GB8308800A GB2137298A GB 2137298 A GB2137298 A GB 2137298A GB 08308800 A GB08308800 A GB 08308800A GB 8308800 A GB8308800 A GB 8308800A GB 2137298 A GB2137298 A GB 2137298A
Authority
GB
United Kingdom
Prior art keywords
filament
mat
wire
adjacent turns
fitting
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Withdrawn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
GB08308800A
Other versions
GB8308800D0 (en
Inventor
David Michael Anthon Kenworthy
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.)
Fusion Plastics Ltd
Original Assignee
Fusion Plastics 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 Fusion Plastics Ltd filed Critical Fusion Plastics Ltd
Priority to GB08308800A priority Critical patent/GB2137298A/en
Publication of GB8308800D0 publication Critical patent/GB8308800D0/en
Publication of GB2137298A publication Critical patent/GB2137298A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D23/00—Producing tubular articles
    • B29D23/001—Pipes; Pipe joints
    • B29D23/003—Pipe joints, e.g. straight joints
    • B29D23/005—Pipe joints, e.g. straight joints provided with electrical wiring
    • 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
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/56—Winding and joining, e.g. winding spirally
    • B29C53/58—Winding and joining, e.g. winding spirally helically
    • B29C53/78—Winding and joining, e.g. winding spirally helically using profiled sheets or strips
    • B29C53/785—Winding and joining, e.g. winding spirally helically using profiled sheets or strips with reinforcements
    • 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
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L47/00—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
    • F16L47/02—Welded joints; Adhesive joints
    • F16L47/03—Welded joints with an electrical resistance incorporated in the joint
    • 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
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L47/00—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
    • F16L47/26—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics for branching pipes; for joining pipes to walls; Adaptors therefor
    • F16L47/28—Joining pipes to walls or to other pipes, the axis of the joined pipe being perpendicular to the wall or to the axis of the other pipe
    • 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
    • B29C66/114—Single butt joints
    • B29C66/1142—Single butt to butt 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
    • B29C66/01—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
    • B29C66/1242—Tongue and groove joints comprising interlocking undercuts
    • B29C66/12421—Teardrop-like, waterdrop-like or mushroom-like interlocking undercuts

Abstract

An electro-fusion saddle fitting for connecting a branch pipe to a main pipe is made by winding an uncoated electrical resistance wire (12) with a filament (10) of thermoplastic material to form a mat (13) incorporating a coiled heating element, and moulding the body (1) of the fitting onto the mat. The fitting is suitable for thermoplastic pipes. <IMAGE>

Description

SPECIFICATION Branch pipe fitting for thermoplastic pipe This invention relates to branch or saddle fittings for connecting a branch pipe to a main pipe of Thermoplastic material, such as poly ethylene. A saddle fitting generally consists of a part-cylindrical body having a concave sur-- face corresponding to the external shape of the main pipe to which it is to be attached, and an integral tubular boss projecting outwardly from the body for connection of a branch pipe, the fitting being moulded from a material which is compatible with, and prefer ably the same as that of the main pipe so that the fitting can be welded directly to the main pipe.The invention is particularly concerned ~with saddle fittings of the electro-fusion type which include an electrical resistance heating element to which an electric current can be supplied to heat and fuse the material of the fitting to that of the main pipe.
The present invention resides in a method of making a saddle fitting which enables the use of uncoated electrical resistance wire whereby manufacturing costs may be reduced and maximum flexibility of choice is ensured in selecting the particular resistance wire to be used in a fitting. According to the invention there is provided a method wherein the uncoated wire is coiled together with an extruded filament of thermoplastic material to form a mat incorporating a spiral heating element and onto which the body of the saddle fitting is moulded.
The invention resides also in a saddle fitting made by the method.
A better un#derstanding of the invention will be had from the following detailed description which is given with reference to the accom panying drawings, in which: Figure 1 is a plan view of a saddle fitting; Figure 2 is an end view of the fitting; Figure 3 is a partial cross-section through a preformed mat used in the manufacture of the fitting; Figure 4 is a section through a filament used in producing the mat preform; and Figures 5 and 6 are section through alternative forms of filament.
The saddle fitting illustrated in Figs. 1 and 2-has a generally semi-cyindrical body 1, an upwardly projecting tubular boss 2 for connection of a branch pipe, lateral flanges 3 for clamping the fitting to a pipe during welding thereto, and electrical connector sockets 5, 6 having pin contacts 7, 8 connected to the opposite ends of an electrical resistance heating winding located adjacent the inner surface of the body 1. The fitting is for the most part formed by injection moulding and the heating element is fixed in position during the moulding process as described below.
Shown in Fig. 4 is an extruded thermoplastic strip or filament 10. In cross-section the filament has the shape of a rectangle with semi-circular grooves 11 in one pair of opposed faces. The radius of the grooves is substantially equal to that of the resistance heating wire to be used in the saddle fitting.
The filament 10 and resistance wire 12 are wound together to form a flat annular mat 13 through which the resistance wire extends in a spiral being received in the confronting grooves 11 of adjacent sections of filament, as seen in Fig. 3, to act as an interlock to prevent displacement of adjacent turns of the filament. The abutting portions of the extruded filament are then fused, e.g. by partial welding such as along a series of radial lines on the upper surface of the mat, to provide a stable preform which can be easily handled.
The opposite ends of the heating wire winding 12 are connected to respective contact pins 7, 8 and the preformed mat incorporating the heater winding is loaded into an injection mould for producing the main body of the saddle fitting. The contacts are inserted into location holes provided in the mould and the mat is deformed into an arcuate shape and supported against a surface of the mould so that it will be positioned at the inner surface of the finished fitting on completion of the moulding process. The material of the mat at its upper surface softens during the injection moulding step and fuses to the material of the body to fix the mat and the heating winding securely to the fitting around the opening of the branch connection 2.
To avoid the need to fuse together the adjacent turns of the filament when producing the mat preform extruded filaments having mechanical interlocking means may be used, such as those shown in Figs. 5 and 6. The filament of Fig. 5 includes a lower section generally of the form shown in Fig. 4 and incorporating grooves 11 to receive the resistance heating wire, and an upper interlock section which includes a continuous bead 15 extending along one side face and a cylindrical groove 16 of greater than 180' arcuate extent extending along the other side face and into which the bead 15 can be engaged to hold together laterally adjacent turns or lengths of the filament.
The extruded filament of Fig. 6 has a locking bead 18 extending along one lateral face and a groove in the opposite face, which groove includes an inner portion 19 adapted to receive the resistance wire as the filament is wound together with the wire, and an outer portion 20 into which the bead of an adjacent turn of filament is engageable to lock mechanically the turns together. The corners of the filament may be chamfered as indicated to facilitate angular movement between the adjacent turns and thereby enable the mat preform to be easily deformed into an arcuate form upon loading into the injection mould.
Of course filaments of other cross-sectional profile are possible and will occur to readers without departing from the invention.
Although described in relation to the manufacture of saddle fittings it is believed that the invention is applicable to sleeve fitting in which case the filament and resistance wire will be wound together to form a cylindrical preform incorporating a helical wire coil.

Claims (12)

1. A method of making an electro-fusion fitting comprising a body of thermoplastic material and an electrical resistance heating winding, wherein the winding is formed from uncoated electrical resistance wire, the wire is coiled together with an extruded filament of thermoplastic material to form a mat incorporating a spiral heating element, and the body of the fitting is moulded onto the mat.
2. A method according to claim 1, wherein the filament has grooves extending along opposite faces thereof, confronting grooves of adjacent turns of filament combining to define a passage in which the wire is received.
3. A method according to claim 2, wherein said grooves are semi-circular in cross-section and have a radius substantially equal to that of the wire.
4. A method according to any one of claims 1, 2 and 3, wherein adjacent turns of the filament are attached together to prevent the mat unwinding prior to moulding the body.
5. A method according to claim 4, wherein adjacent turns of the filament are fused together by at least partial welding.
6. A method according to claim 4, wherein the filament includes interlocking formations interengageable to secure adjacent turns of the filament together.
7. A method according to claim 6 wherein said formations comprise a bead extending along a face of the filament, and a groove extending along the opposite face of the filament.
8. A method according to claim 1, 2 or 3, wherein the filament includes a groove which receives the wire and is closed off by an adjacent length of filament in the coiled mat.
9. A method according to claim 8, wherein the face of the filament opposite the groove is provided with a locking bead for locking engagement in the groove to secure adjacent turns of filament together.
10. A method according to claim 8 or 9, wherein the corners of the filament are chamfered to facilitate angular movement between adjacent turns.
11. A method of making an electro-fusion Tilting substantially as described herein.
12. An electro-fusion fitting made by the method of any one of claims 1 to 11.
GB08308800A 1983-03-30 1983-03-30 Branch pipe fitting Withdrawn GB2137298A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08308800A GB2137298A (en) 1983-03-30 1983-03-30 Branch pipe fitting

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08308800A GB2137298A (en) 1983-03-30 1983-03-30 Branch pipe fitting

Publications (2)

Publication Number Publication Date
GB8308800D0 GB8308800D0 (en) 1983-05-11
GB2137298A true GB2137298A (en) 1984-10-03

Family

ID=10540491

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08308800A Withdrawn GB2137298A (en) 1983-03-30 1983-03-30 Branch pipe fitting

Country Status (1)

Country Link
GB (1) GB2137298A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02238929A (en) * 1988-11-21 1990-09-21 Central Plastics Co Electric heating element for melting thermoplastic material
EP0402201A2 (en) * 1989-06-09 1990-12-12 Boulet-D'auria, Terlizzi & Cie Wire with shaped coating, especially for making an electro-fusion insert
EP0589835A1 (en) * 1992-09-22 1994-03-30 Streng Plastic AG Thermoelectric welded joint of thermoplastic materials

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1408844A (en) * 1972-02-08 1975-10-08 Rollmaplast Ag Boring saddles for branch pipe connections

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1408844A (en) * 1972-02-08 1975-10-08 Rollmaplast Ag Boring saddles for branch pipe connections

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02238929A (en) * 1988-11-21 1990-09-21 Central Plastics Co Electric heating element for melting thermoplastic material
EP0402201A2 (en) * 1989-06-09 1990-12-12 Boulet-D'auria, Terlizzi & Cie Wire with shaped coating, especially for making an electro-fusion insert
FR2648076A1 (en) * 1989-06-09 1990-12-14 Boulet D Auria Terlizzi PROFILE SOLDER WIRE, IN PARTICULAR FOR FORMING AN ELECTRO-WELDING INSERT
EP0402201A3 (en) * 1989-06-09 1992-03-18 Boulet-D'auria, Terlizzi & Cie Wire with shaped coating, especially for making an electro-fusion insert
US5107098A (en) * 1989-06-09 1992-04-21 Boulet D'auria Terlizzi And Gaz De France Profiled sheathed wire for forming into an electric resistance welding insert
EP0589835A1 (en) * 1992-09-22 1994-03-30 Streng Plastic AG Thermoelectric welded joint of thermoplastic materials
US5387305A (en) * 1992-09-22 1995-02-07 Streng Plastic Ag Method for producing a theroelectrically weldable zone in a thermoplastic material

Also Published As

Publication number Publication date
GB8308800D0 (en) 1983-05-11

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