GB2177558A - Fusion welding of plastics pipes - Google Patents
Fusion welding of plastics pipes Download PDFInfo
- Publication number
- GB2177558A GB2177558A GB8614796A GB8614796A GB2177558A GB 2177558 A GB2177558 A GB 2177558A GB 8614796 A GB8614796 A GB 8614796A GB 8614796 A GB8614796 A GB 8614796A GB 2177558 A GB2177558 A GB 2177558A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coupling
- fusion
- control circuit
- sensor
- generator
- 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- Withdrawn
Links
- 230000004927 fusion Effects 0.000 title claims description 26
- 238000004023 plastic welding Methods 0.000 title claims description 8
- 230000008878 coupling Effects 0.000 claims abstract description 54
- 238000010168 coupling process Methods 0.000 claims abstract description 54
- 238000005859 coupling reaction Methods 0.000 claims abstract description 54
- 238000004804 winding Methods 0.000 claims abstract description 33
- 238000007499 fusion processing Methods 0.000 claims abstract description 20
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 16
- 229920003023 plastic Polymers 0.000 claims abstract description 9
- 239000004033 plastic Substances 0.000 claims abstract description 9
- 238000003466 welding Methods 0.000 claims abstract description 7
- 230000001105 regulatory effect Effects 0.000 claims abstract description 3
- 239000004065 semiconductor Substances 0.000 claims abstract description 3
- 230000005284 excitation Effects 0.000 claims description 8
- 230000001276 controlling effect Effects 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 2
- 230000008901 benefit Effects 0.000 claims description 2
- 210000001503 joint Anatomy 0.000 claims description 2
- -1 polyethylene Polymers 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 230000004044 response Effects 0.000 claims description 2
- 230000000007 visual effect Effects 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract 1
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
- B29C65/02—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
-
- 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
-
- 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
-
- 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
- B29C66/90—Measuring or controlling the joining process
- B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
- B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
- B29C66/9161—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
- B29C66/91651—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating
- B29C66/91653—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating by controlling or regulating the voltage, i.e. the electric potential difference or electric tension
-
- 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
- B29C66/90—Measuring or controlling the joining process
- B29C66/96—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process
- B29C66/961—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process involving a feedback loop mechanism, e.g. comparison with a desired value
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/275—Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
- G05D23/27535—Details of the sensing element
- G05D23/27543—Details of the sensing element using the controlled element as sensing element
-
- 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
- B29C66/70—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
- 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
- B29C66/90—Measuring or controlling the joining process
- B29C66/92—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools
- B29C66/922—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by measuring the pressure, the force, the mechanical power or the displacement of the joining tools
- B29C66/9221—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by measuring the pressure, the force, the mechanical power or the displacement of the joining tools by measuring the pressure, the force or the mechanical power
-
- 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
- B29C66/90—Measuring or controlling the joining process
- B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
- B29C66/944—Measuring or controlling the joining process by measuring or controlling the time by controlling or regulating the time
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
Plastics material pipes 10, 12 are built joined by means of an electrofusion coupling 14 having a heating coil 16 energised by the output winding 24 of an electrical generator 20 which has a field winding 22 controlled by a control circuit 26. The coupling has a pressure sensor 18 which monitors the build up of pressure which occurs in the coupling during the fusion process and, through the control circuit 26, inhibits the field winding 22 when the pressure indicates that the fusion process is complete. Alternatively, control circuit 26 may receive an input from a timer 28 to terminate the welding process. The output voltage of the generator may also be regulated by means of the circuit 26 which may have a sensing input connected at the load lid of the output power cables to compensate for voltage drop in the latter. The system eliminates the need for power semiconductors and contactors resulting in savings in weight and cost. <IMAGE>
Description
SPECIFICATION
Improvements in and relating to fusion welding
The present invention relates to fusion welding of plastics material pipes.
Fusion welding is commonly used for the jointing of plastics material pipes using a special tubular plastics material coupling which has a heating element embedded in the wall of the coupling adjacent the inner surface. The heating element is normally in the form of an electrical heating coil concentric with the coupling and in use this is connected through a control system to an electrical generator. The latter is normally a standard 110V
A.C. generator whose output is regulated to provide an nominal 40V A.C. stabilised supply fed to the control system. The control system is used by an operator to control application of the voltage to the coupling heating coil.
In order to butt joint two pipes, the pipe ends are inserted into the coupling and power is applied to the heating coil via the control system. Once fusion is completed power is switched off. Removal of power can be effected manually by an operator in response to a visual indication that fusion is complete, or can be effected automatically by sensors located in the coupling which monitor, for example, a build up of pressure during fusion and trip the power on/off switch when pressure reaches a predetermined value. Alternatively, an electronic timer may be used to control the fusion cycle.
A major disadvantage with current systems is the use of expensive and bulky circuitry to regulate the generator output and control the application of power to the coupling heating coil.
The present invention seeks to provide an improved system for fusion welding.
Accordingly, the present invention provides a system for the fusion welding of plastics material pipes using an electrofusion coupling comprises an electrical generator having an output winding for supplying power to said coupling, a field winding for said output winding, and a control circuit for controlling excitation of said field winding, said control circuit having an input connectable to a sensor of said coupling or to a timer circuit for indicating completion of said fusion process whereby said control circuit is responsive to said sensor or said timer circuit indicating completion of said fusion process to inhibit operation of said field winding.
The present invention is further described hereinafter, by way of example, with reference to the accompanying drawing which illustrates a preferred embodiment of the present invention.
The drawing shows two plastics material pipes 10, 12 which may be used to carry, for example, water or gas and which are to be butt jointed by means of an electrofusion coupling 14. The pipes and the coupling are made of a suitable plastics material such as polyethylene.
The coupling 14 has a heating element in the form of an electrical resistance coil 16 which is embedded in the wall of the coupling, coaxial with the coupling, adjacent the inner wall of the coupling. The coupling may have a sensor 18 which may conveniently be a pressure sensor monitoring the build up of pressure which occurs in the coupling during the fusion process, or some other suitable sensor. Alternatively a timer circuit 28 may be used to control the fusion process.
The coil 16 of the coupling is connected to the output of a generator 20 which has a field winding 22 which is energised to induce power in the generator output winding 24. Control of excitation current in the field winding 22 is effected by means of a control circuit 26.
The control circuit 26 has an input which is connectable to the sensor or the timer circuit 28 to receive a feed back signal such that once fusion is completed the feed back signal fed to the control circuit causes the latter to inhibit energisation of the field winding 22 with the result that the generator output voltage applied to the heating coil 16 is interrupted to end the fusion process.
The sensor 18 can be a simple switch which opens or closes when fusion is complete, or can be a more sophisticated form of sensor.
The output voltage applied to the heating coil 16 is about 40V and this can be supplied direct by the generator output winding, or alternatively, the generator can provide a higher voltage which is stepped down to the desired level.
The control circuit 26 can conveniently be an automatic voltage regulator which regulates the generator output voltage. The sensing terminals can be connected at the load end of the power cables thus compensating for any voltage drop.
The above-described system has the advantage of eliminating the need for power semiconductors and contactors and results in a lightweight control unit having considerable cost savings over other designs.
1. A system for the fusion welding of plastics material pipes using an electrofusion coupling comprises an electrical generator having an output winding for supplying power to said coupling; a field winding for said output winding; and a control circuit for controlling excitation of said field winding, said control circuit having an input connectable to means for indicating completion of said fusion process whereby said control circuit is responsive to said means indicating completion of said fusion process to inhibit excitation of said field winding.
2. A system as claimed in claim 1 wherein said means comprises a timing circuit.
3. A system as claimed in claim 1 wherein said means comprises a sensor of said coupling for sensing a parameter indicating completion of said fusion process.
4. A system as claimed in claim 3 wherein said sensor is a pressure sensor for monitoring the build up of pressure in said coupling during the fusion process.
5. A system as claimed in any of claims 1 to 4
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (7)
1. A system for the fusion welding of plastics material pipes using an electrofusion coupling comprises an electrical generator having an output winding for supplying power to said coupling; a field winding for said output winding; and a control circuit for controlling excitation of said field winding, said control circuit having an input connectable to means for indicating completion of said fusion process whereby said control circuit is responsive to said means indicating completion of said fusion process to inhibit excitation of said field winding.
2. A system as claimed in claim 1 wherein said means comprises a timing circuit.
3. A system as claimed in claim 1 wherein said means comprises a sensor of said coupling for sensing a parameter indicating completion of said fusion process.
4. A system as claimed in claim 3 wherein said sensor is a pressure sensor for monitoring the build up of pressure in said coupling during the fusion process.
5. A system as claimed in any of claims 1 to 4 wherein said coupling has a heating element in the form of an electrical resistance coil embedded in the wall of the coupling and coaxial with the coupling.
6. A system as claimed in claim 5 wherein said resistance coil is adjacent the inner wall of the coupling.
7. A system for the fusion welding of plastics material pipes using an electrofusion coupling substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB858515338A GB8515338D0 (en) | 1985-06-18 | 1985-06-18 | Fusion welding |
| GB858529044A GB8529044D0 (en) | 1985-11-26 | 1985-11-26 | Fusion welding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8614796D0 GB8614796D0 (en) | 1986-07-23 |
| GB2177558A true GB2177558A (en) | 1987-01-21 |
Family
ID=26289386
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8614796A Withdrawn GB2177558A (en) | 1985-06-18 | 1986-06-18 | Fusion welding of plastics pipes |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2177558A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0352128A3 (en) * | 1988-07-21 | 1991-06-12 | Mitsui Petrochemical Industries, Ltd. | Electrofusion socket with fusion state indicating means |
| US5407514A (en) * | 1988-02-03 | 1995-04-18 | E. O. Butts Consultants Ltd. | Method for welding thermoplastic materials |
| WO1995016557A3 (en) * | 1993-12-15 | 1996-02-29 | Tokushu Kogyo Kabushikigaisha | Electrofusion fastening apparatus |
| EP0927097A4 (en) * | 1995-06-28 | 1999-08-11 | ||
| US6368448B1 (en) * | 1998-01-09 | 2002-04-09 | G P Daikyo Corporation | Method for joining thermoplastic resin molded products |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB432041A (en) * | 1933-01-21 | 1935-07-19 | Vertriebs Ges Des Leipziger Le | Device for producing extremely high impulses of energy of short duration |
| GB530450A (en) * | 1938-06-18 | 1940-12-12 | Vertriebs Ges Des Leipziger Le | Improvements in and relating to the production of high impulses of energy of short duration |
| GB1068619A (en) * | 1963-12-03 | 1967-05-10 | Nord Aviation | Improved welding apparatus |
| US3752348A (en) * | 1971-08-30 | 1973-08-14 | Ford Motor Co | Motor vehicle electrically heated windshield and backlight system |
| GB1445187A (en) * | 1973-01-26 | 1976-08-04 | Maremont Corp | Arc welding |
| GB1574190A (en) * | 1976-09-21 | 1980-09-03 | Reeh H | Electric welding apparatus |
-
1986
- 1986-06-18 GB GB8614796A patent/GB2177558A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB432041A (en) * | 1933-01-21 | 1935-07-19 | Vertriebs Ges Des Leipziger Le | Device for producing extremely high impulses of energy of short duration |
| GB530450A (en) * | 1938-06-18 | 1940-12-12 | Vertriebs Ges Des Leipziger Le | Improvements in and relating to the production of high impulses of energy of short duration |
| GB1068619A (en) * | 1963-12-03 | 1967-05-10 | Nord Aviation | Improved welding apparatus |
| US3752348A (en) * | 1971-08-30 | 1973-08-14 | Ford Motor Co | Motor vehicle electrically heated windshield and backlight system |
| GB1445187A (en) * | 1973-01-26 | 1976-08-04 | Maremont Corp | Arc welding |
| GB1574190A (en) * | 1976-09-21 | 1980-09-03 | Reeh H | Electric welding apparatus |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5407514A (en) * | 1988-02-03 | 1995-04-18 | E. O. Butts Consultants Ltd. | Method for welding thermoplastic materials |
| EP0352128A3 (en) * | 1988-07-21 | 1991-06-12 | Mitsui Petrochemical Industries, Ltd. | Electrofusion socket with fusion state indicating means |
| WO1995016557A3 (en) * | 1993-12-15 | 1996-02-29 | Tokushu Kogyo Kabushikigaisha | Electrofusion fastening apparatus |
| EP0927097A4 (en) * | 1995-06-28 | 1999-08-11 | ||
| US6368448B1 (en) * | 1998-01-09 | 2002-04-09 | G P Daikyo Corporation | Method for joining thermoplastic resin molded products |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8614796D0 (en) | 1986-07-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |