JP2018035845A - Electric fusion joint and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose an electric fusion joint capable of stabilizing fusion temperature or fusion strength to prevent a water leakage accident.SOLUTION: An electric fusion joint includes a joint body having a socket part, and a planar heating element covering an inner peripheral surface of the socket part. The planar heating element includes an electrification terminal, a metal thin film pattern configured to generate heat with electrification through the electrification terminal, and an insulation film covering at least one surface side of the metal thin film pattern and fused with heating of the metal thin film pattern. The metal thin film pattern is arranged between the insulation film covering the one surface side and an inner peripheral surface of the socket part.SELECTED DRAWING: Figure 2

Description

  The present application discloses an electric fusion joint and a manufacturing method thereof.

  An electric fusion joint is widely used as a joint for connecting resin pipes. In the electric fusion joint, a heating wire is embedded in the inner peripheral surface of the insertion portion (receiving portion) of the pipe to be connected in the joint body (Patent Documents 1 to 5 and the like). After inserting the pipe into the receiving portion of the joint body, the joint body and the pipe can be joined by heating the heating wire by energization and melting the vicinity of the joint surface. In this case, it is necessary to adjust the heating temperature of the heating wire by controlling energization to the heating wire (Patent Document 6 and the like). Various methods have been proposed for energization control of electric fusion joints. Recently, bar code information in which energization control information such as voltage, current, and energization time to be supplied to the electrofusion joint is recorded. A so-called bar code control method is also performed in which a bar code reader connected to the fusion controller with a cable is used to perform predetermined energization control based on the read information.

JP, 2006-035327, A JP 2006-153260 A Japanese Patent No. 5654724 Japanese Patent No. 5053784 Japanese Patent No. 3561600 Japanese Patent No. 5637228

  In a conventional electric fusion joint using a heating wire, a short circuit is likely to occur between the layers of the heating wire or adjacent to each other during the fusion work. As a result, the fusing temperature is non-uniform, the strength is lowered, and there is a risk of leaking water. Further, since the heating wire is thin and long, the resistance value change due to energization heat generation tends to be large. As a result, it becomes difficult to control the heat generation temperature, and the fusion strength is likely to vary or decrease. Furthermore, since the heating wire is usually covered with an insulating coating, the surface shape after the insulating coating is circular or substantially square, so that the surface to be fused with the tube tends to be uneven. As a result, the insulation coating is likely to be damaged when the tube is inserted, and the heating wire may be exposed at the time of fusion, resulting in a gap between the insulation coating and the heating wire, which may lead to water leakage from the current-carrying terminal. There is. In addition, when the bar code control method is adopted, there is a problem in that the fusion under the proper fusing condition is not performed due to a misread of the bar code, resulting in a short circuit abnormality or a poor fusing.

  In view of the above background art, the present application discloses an electric fusion joint in which the fusion temperature and the fusion strength are stable and a water leakage accident is unlikely to occur.

This application is one of the means for solving the above-described problems.
A metal thin film comprising a joint main body having a receiving part and a sheet heating element covering an inner peripheral surface of the receiving part, wherein the sheet heating element generates heat when energized via an energizing terminal and the energizing terminal. An insulating film that covers at least one surface side of the metal thin film pattern and melts by heat generation of the metal thin film pattern, and the metal thin film pattern covers the one surface side of the insulating film and the receiving portion. An electrofusion joint is disclosed that is disposed between the peripheral surface and the peripheral surface.

The “receiving part” refers to a part where a pipe can be inserted and the pipe and the electric fusion joint can be joined.
The “joint body” is not particularly limited as long as it has a receiving portion and can connect a pipe as a joint.
The “inner peripheral surface of the receiving portion” refers to the inner wall of the receiving portion of the joint body.
“A planar heating element covering the inner peripheral surface of the receiving portion” means that a planar heating element is provided along the shape of the inner peripheral surface of the receiving portion. The planar heating element is preferably provided so as to cover the entire circumference of the inner peripheral surface of the receiving portion.
The “metal thin film pattern” refers to a pattern made of a metal thin film, for example, a metal foil patterned by punching or etching. The metal thin film pattern has a predetermined thickness and a predetermined pattern width, and the shape is clearly different from the heating wire.
In other words, “insulating film covering at least one surface side of the metal thin film pattern” means that the metal thin film pattern is formed on the surface of the insulating film. The insulating film may cover both one side and the other side of the metal thin film pattern, and in this case, the metal thin film pattern is sandwiched between the insulating films.
“The metal thin film pattern is disposed between the insulating film covering the one surface side and the inner peripheral surface of the receiving portion”, in other words, the surface of the metal thin film pattern by the insulating film covering the one surface side. Is a protected form. In addition, when the metal thin film pattern is covered with an insulating film on both one side and the other side, there is an insulating film covering the other side between the metal thin film pattern and the inner peripheral surface of the receiving portion. Will be.

  In the electric fusion joint of the present disclosure, it is preferable that the electric resistance of the metal thin film pattern is 0.1Ω or more and 5.0Ω or less.

  In the electrofusion joint of the present disclosure, it is preferable that the joint body is made of a crosslinked thermoplastic resin and the insulating film is made of a non-crosslinked thermoplastic resin.

  In the electric fusion joint of the present disclosure, it is preferable that the metal constituting the metal thin film pattern includes iron or an iron-based alloy.

  In the electric fusion joint according to the present disclosure, the joint body may include at least two or more of the receiving portions. In this case, the metal thin film pattern of the planar heating element that covers the inner peripheral surface of the one receiving portion, and the metal thin film pattern of the planar heating element that covers the inner peripheral surface of the other receiving portion, It is preferable to have an equivalent electric resistance.

  In the electric fusion joint of the present disclosure, when the joint body has at least two or more of the receiving portions, an inner diameter of the one receiving portion and an inner diameter of the other receiving portion are different from each other. Also good.

This application is one of the means for solving the above-described problems.
A step of providing a heating element so as to cover the inner peripheral surface of the receiving part with respect to the joint body having the receiving part, and as the heating element, a metal that generates heat by energization terminal and energization through the energization terminal A sheet heating element comprising a thin film pattern and an insulating film that covers one side of the metal thin film pattern and melts by heat generation of the metal thin film pattern, and the insulating film that covers the one side of the metal thin film pattern, Disclosed is a method for manufacturing an electrofusion joint, which is disposed between the inner peripheral surface of the receiving portion.

  In the manufacturing method of this indication, it is preferable that the electrical resistance of the said metal thin film pattern is 0.1 to 5.0 ohm.

  In the manufacturing method of the present disclosure, it is preferable to adjust the shape and / or resistance value of the metal thin film pattern by laser trimming.

  In the production method of the present disclosure, it is preferable to use a joint body made of a crosslinked thermoplastic resin as the joint body, and use a film made of a non-crosslinked thermoplastic resin as the insulating film.

  In the manufacturing method of this indication, it is preferable to use the metal containing iron or an iron-base alloy as a metal which comprises the said metal thin film pattern.

  In the manufacturing method of the present disclosure, in the case where the planar heating element is provided on the inner peripheral surface of each of the receiving portions with respect to the joint body having at least two receiving portions, the one receiving port It is preferable to use an equivalent metal thin film pattern for the planar heating element that covers the inner peripheral surface of the part and the planar heating element that covers the inner peripheral surface of the other receiving part.

  In the manufacturing method of the present disclosure, when a joint main body having at least two or more receiving portions is used, the joint main body is different in inner diameter of the one receiving portion and the inner diameter of the other receiving portion. It can also be used.

  In the manufacturing method of the present disclosure, in the case of manufacturing a plurality of electric fusion joints using a plurality of the joint bodies, the planar heating element provided in one joint body and the other joint body provided in the above For the planar heating element, it is preferable to use a metal thin film pattern having the same electrical resistance.

  In the electric fusion joint of the present disclosure, a predetermined planar heating element is provided as a heating element that generates heat when energized. Since the surface heating element has less surface irregularities, it can be surface-bonded to the inserted tube. Therefore, the fusion quality is improved and the occurrence of water leakage trouble can be suppressed. Further, since the surface heating element has less surface irregularities, the occurrence of scratches on the surface of the sheet heating element is suppressed when a tube is inserted. Therefore, generation | occurrence | production of the water supply after melt | fusion can be suppressed, and generation | occurrence | production of a water leak trouble can be suppressed. Further, the planar heating element can easily adjust the resistance value regardless of the size by adjusting the shape of the metal thin film pattern. Therefore, the control voltage and current can be kept constant during energization, and the control circuit can be simplified. As a result, the fusion quality is greatly improved. Furthermore, the planar heating element can also shorten the length of the metal thin film pattern as compared with the heating wire, and there is little change in resistance due to temperature rise due to energization. As a result, it is not necessary to finely change the energization control, and the fusion quality can be easily made constant. As described above, the electric fusion joint of the present disclosure has a stable fusion temperature and fusion strength, and is unlikely to cause a water leakage accident.

1 is a schematic diagram for explaining an external structure of an electric fusion joint 10. 2 is a schematic cross-sectional view for explaining the internal structure of the electric fusion joint 10. FIG. FIG. 3 is a schematic diagram for explaining a planar heating element 2. FIG. 3 is a schematic diagram for explaining a planar heating element 2. 3 is a schematic diagram for explaining an example of a method for manufacturing the electric fusion joint 10. FIG.

1. Electrical Fusion Joint FIGS. 1 and 2 schematically show an electrical fusion joint 10. As shown in FIGS. 1 and 2, the electrofusion joint 10 includes a joint body 1 having a receiving portion 1 a and a planar heating element 2 that covers an inner peripheral surface of the receiving portion 1 a, and the planar shape. The heating element 2 covers the energizing terminal 2a, the metal thin film pattern 2b that generates heat by energization through the energizing terminal 2a, and the insulation that covers at least one side of the metal thin film pattern 2b and melts by the heat generation of the metal thin film pattern 2b. The metal thin film pattern 2b is disposed between the insulating film 2c covering the one surface side and the inner peripheral surface of the receiving portion 1a.

1.1. Joint Body The joint body 1 may have any shape as long as it has a receiving portion and can connect a pipe as a joint. It is possible to adopt the same shape as the joint body of the conventional electric fusion joint. In FIGS. 1 and 2, a cheese type is shown, but any other known shape such as a socket type, an elbow type, a reducer type, a cap type, etc. can be adopted.

  The material of the joint body 1 may be any material that can connect a pipe and can exhibit the performance as an electrofusion joint. The same material as the joint body of the conventional electric fusion joint can be used. In particular, considering moldability, mechanical properties, durability, and the like, those made of a crosslinked thermoplastic resin are preferred, and those made of a crosslinked polyethylene are particularly preferred.

  The joint body 1 has a receiving part 1a in the vicinity of the opening, and a pipe to be connected to the receiving part 1a is inserted to join the joint body 1 and the pipe. As shown in FIGS. 1 and 2, the joint body 1 may have at least two receiving portions 1 a. Further, as described above, the joint body 1 may have a diameter different from the inner diameter of one receiving portion 1a and the other receiving portion 1a, such as a reducer type. What is necessary is just to design according to the shape of the pipe | tube which should be connected about the shape of the receptacle part 1a. Further, a current-carrying terminal 2a protrudes from the joint body 1, and it is possible to energize the metal thin film pattern 2b of the sheet heating element 2 inside through this. What is necessary is just to design according to the magnitude | size of the planar heating element 2, and the magnitude | size of the energization terminal 2a about the location and the magnitude | size of a hole which provide the hole for projecting the energization terminal 2a.

1.2. Planar Heating Element FIG. 3 schematically shows an example of the sheet heating element 2. As shown in FIG. 3, the sheet heating element 2 includes an energizing terminal 2a, a metal thin film pattern 2b that generates heat when energized via the energizing terminal 2a, and at least one surface side of the metal thin film pattern 2b and the metal thin film. And an insulating film 2c that is melted by the heat generated by the pattern 2b.

  The energization terminal 2a may be any terminal capable of energizing the metal thin film pattern 2b. For example, a conventionally known metal terminal can be used. The energizing terminal 2a is joined to the metal thin film pattern 2b. The joining method is not particularly limited. For example, bonding is possible by ultrasonic welding, laser welding, or the like. The energizing terminal 2a may be configured to form the planar heating element 2 by being joined to the metal thin film pattern 2b in the electric fusion joint 10. That is, before being provided in the receiving portion 1a of the joint body 1, the energizing terminal 2a and the metal thin film pattern 2b may be separated from each other without being joined.

  The metal thin film pattern 2b is formed by forming a metal foil having a predetermined thickness into a predetermined pattern shape. Any known method can be adopted as a method of forming the metal thin film pattern 2b, and is not particularly limited. For example, a blanking method, a laser trimming method, a subtractive method (etching), an additive method ( Known methods such as plating) and conductor printing method (conductive paste) can be applied. Although the thickness of the metal thin film pattern 2b is not specifically limited, For example, it is 1 micrometer or more and 100 micrometers or less. The lower limit is preferably 5 μm or more, more preferably 10 μm or more, and the upper limit is preferably 75 μm or less, more preferably 50 μm or less. Thus, by making it a thin film-like pattern with small thickness, even when covered with the insulating film 2c, an excessive unevenness | corrugation is not produced in the insulating film 2c.

  The metal thin film pattern 2b has a predetermined width and a predetermined length, and one end and the other end are joined to the energization terminals 2a and 2a, respectively. The length and width of the metal thin film pattern 2b are not particularly limited, and may be designed according to the length of the inner periphery of the receiving port 1a to be covered and the target resistance value.

  The electric resistance of the metal thin film pattern 2b is preferably 0.1Ω to 5.0Ω. The lower limit is more preferably 0.5Ω or more, further preferably 1Ω or more, and the upper limit is more preferably 4Ω or less, still more preferably 3Ω or less. When the metal thin film pattern 2b has such an electrical resistance, it becomes easier to generate heat to a desired temperature by energization.

When the joint body 1 has at least two or more receiving portions 1a, 1a,..., The metal thin film pattern 2b of the sheet heating element 2 covering the inner peripheral surface of the one receiving portion 1a and the other receiving portions. It is preferable that the metal thin film pattern 2b of the planar heating element 2 covering the inner peripheral surface of the mouth 1a has an equivalent electric resistance. The metal thin film pattern 2b can be easily adjusted in pattern shape by laser trimming, and the electric resistance value can be precisely controlled. That is, the resistance value of the metal thin film pattern 2b can be easily made uniform by one planar heating element 2 and the other planar heating element 2. The electrical resistance value can be set to a desired value by appropriately adjusting the material and thickness of the metal thin film to be used and the length and width of the metal thin film pattern 2b. The “equivalent electric resistance” means that the ratio (Ω ₁ / Ω ₂ ) between the electric resistance (Ω ₁ ) of _one metal thin film pattern 2 b and the electric resistance (Ω ₂ ) of another metal thin film pattern 2 b is 0. It means that it is in the range of .99 or more and 1.01 or less, and more preferably that Ω ₁ / Ω ₂ is in the range of 0.999 or more and 1.001 or less. The metal thin film pattern 2b of the two or more receiving portions 1a, 1a,... Has an electric resistance value within a range of ± 1% of a target resistance value, particularly within a range of ± 0.1%. It is preferable from the viewpoint of controlling the fusion temperature.

  Note that, in the electric fusion joint 10, even if the inner diameter of the one receiving portion 1 a is different from the inner diameter of the other receiving portion 1 a, one planar heat generation covering the one receiving portion 1 a. The resistance value of the metal thin film pattern 2b can be easily aligned between the body 2 and another planar heating element 2 covering the other receiving portion 1b.

  The material of the metal thin film pattern 2b may be any material as long as it generates heat when energized and the temperature of the heat generation can rise to a melting temperature of an insulating film 2c described later. For example, iron, an iron base alloy, aluminum, a nickel-chromium alloy, etc. are mentioned. In particular, it is preferable to use a metal containing iron or an iron-based alloy. An iron-based alloy refers to an alloy containing 50% by mass or more of iron. Specifically, stainless steel and the like are applicable. When the metal constituting the metal thin film pattern 2b includes iron or an iron-based alloy, the temperature of heat generated by energization increases. That is, the insulating film 2c can be melted more easily.

  The insulating film 2c covers at least one side of the metal thin film pattern 2b. The size and thickness of the insulating film 2c are not particularly limited. What is necessary is just to design according to the shape of the internal peripheral surface of the receiving part 1a. In particular, it is preferable to have a size that can cover the entire circumference of the inner peripheral surface of the receiving portion 1a. The thickness of the insulating film 2c can be, for example, 1 μm or more and 200 μm or less. The lower limit is preferably 5 μm or more, more preferably 10 μm or more, and the upper limit is preferably 150 μm or less, more preferably 100 μm or less. By setting it as such thickness, even when the metal thin film pattern 2b is covered with the insulating film 2c, it is difficult to cause excessive unevenness in the insulating film 2c or to expose the heating wire. The fusion strength with the tube is more stable, and a water leakage accident is less likely to occur.

  As shown in FIG. 4, the insulating film 2c may cover both the one surface side and the other surface side of the metal thin film pattern 2b. That is, the metal thin film pattern 2b may be in a state of being sandwiched between two insulating films 2c. Thereby, handling of the planar heating element 2 becomes easier.

The material of the insulating film 2c may be any material that melts when the metal thin film pattern 2b generates heat by energization, and a non-crosslinked or crosslinked thermoplastic resin can be used. Examples include polyolefins such as polyethylene and polybutene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyarylene sulfides such as polyphenylene sulfide (PPS), polyimide, polyamide, epoxy resin, polyvinyl chloride, and synthetic rubber. In view of flexibility, insulation, and cost, those made of non-crosslinked thermoplastic resins are preferred, and those made of non-crosslinked polyethylene are particularly preferred. The material of the insulating film 2c is preferably similar to that of the joint body 1. That is, when the material of the joint body 1 is a crosslinked thermoplastic resin, the material of the insulating film 2c is preferably a non-crosslinked thermoplastic resin, and when the material of the joint body 1 is crosslinked polyethylene, the material of the insulating film 2c. Is preferably non-crosslinked polyethylene.
As a method for producing the insulating film 2c, a known method such as an extrusion casting method using a T-die or a calendering method can be adopted, and the film forming property, stable productivity, etc. are not particularly limited. From this aspect, the extrusion casting method using a T die is preferable.

The manufacturing method of the planar heating element 2 including the energizing terminal 2a, the metal thin film pattern 2b, and the insulating film 2c is not particularly limited, and a known method can be adopted. It can be manufactured by the following manufacturing method.
The current-carrying terminal 2a is joined to the metal pattern 2b by ultrasonic welding, laser welding, or the like, and the insulating film 2c is disposed so as to cover at least one surface side of the obtained metal pattern 2b with the current-carrying terminal 2a. Under the present circumstances, you may interpose a well-known adhesive agent or an adhesive as needed between the metal pattern 2b and the insulating film 2c. Subsequently, the sheet heating element 2 can be manufactured by melting and bonding them with a hot press machine or the like. When using an adhesive or a pressure-sensitive adhesive, the hot pressing step may be omitted.

1.3. Other Configurations The electric fusion joint 10 is composed of the joint body 1 and the planar heating element 2 described above. Here, the metal thin film pattern 2b of the planar heating element 2 is disposed between the insulating film 2c covering the one surface side and the inner peripheral surface of the receiving portion 1a. By adopting such a configuration, the metal thin film pattern 2b is protected by the insulating film 2c. For example, even when a tube is inserted into the receiving portion 1a, the metal thin film pattern 2b is not peeled off due to friction. . Moreover, since the metal thin film pattern 2c is thinner than the conventional heating wire, the unevenness | corrugation of the surface of the insulating film 2c can be reduced. That is, when joining the tubes, the surface heating element 2 can be used for surface bonding.

2. Method for Producing Electrical Fusion Joint The electric fusion joint 10 can be produced, for example, by the following production method. That is, a step of providing a heating element so as to cover the inner peripheral surface of the receiving portion 1a is provided to the joint body 1 having the receiving portion 1a. The sheet heating element 2 includes a metal thin film pattern 2b that generates heat due to heat and an insulating film 2c that covers one surface side of the metal thin film pattern 2b and melts due to heat generation of the metal thin film pattern 2b. It is the manufacturing method of the electrofusion joint 10 arrange | positioned between the insulating film 2c which covers and the inner peripheral surface of the receiving part 1a.

  The method of providing the sheet heating element 2 on the electric fusion joint 10 is not particularly limited as long as the sheet heating element 2 can be disposed so as to cover the receiving portion 1a. For example, the sheet heating element 2 is curved to form a cylindrical body along the opening of the joint body 1 and the inner diameter of the receiving portion 1a, and the cylindrical body is placed in a molding die and integrally molded with the joint body. Is preferably adopted. At this time, the energization terminal 2a may be molded and integrated so as to protrude from a hole provided at a predetermined location of the joint body 1 to the outside. As another method, as shown in FIG. 5 (A), the cylindrical body is inserted from the opening of the joint body 1 into the inner receiving portion 1a to cover the receiving portion 1a. The heating element 2 can be arranged. At this time, the energizing terminal 2a may be protruded from a hole provided at a predetermined location of the joint body 1 to the outside. Alternatively, as shown in FIG. 5B, when the planar heating element 2 is disposed in the receiving portion 1a, the energizing terminal 2a is prepared separately from the metal thin film pattern 2b and the insulating film 2c, and the metal thin film pattern After arranging 2b and the insulating film 2c in the receiving part 1a, the conduction | electrical_connection terminal 2a is joined to the predetermined position of the metal thin film pattern 2b through the hole provided in the coupling main body 1, and the planar heating element 2 is attached. It may be configured. The planar heating element 2 may be fixed to the inner peripheral surface of the receiving portion 1a, or may simply be placed. It is also possible to fix the planar heating element 2 so as to be fitted to the surface shape of the receiving portion 1a.

  The details of the joint body 1 and the planar heating element 2 are as described above. That is, the electrical resistance of the metal thin film pattern 2b is preferably 0.1Ω or more and 5.0Ω or less. Moreover, although the shape and resistance value of the metal foil film pattern 2b can be adjusted by various methods, it is particularly preferable to adjust the shape and / or resistance value of the metal thin film pattern 2b by laser trimming. Moreover, it is preferable to use the joint main body 1 which consists of a crosslinked thermoplastic resin as the joint main body 1, and to use the film which consists of a non-crosslinked thermoplastic resin as the insulating film 2c. Moreover, it is preferable to use the metal containing iron or an iron-base alloy as a metal which comprises a metal thin film pattern. Further, in the case where the planar heating element 2 is provided on the inner peripheral surface of each of the receiving portions 1a with respect to the joint body 1 having at least two receiving portions 1a, For the sheet heating element 2 covering the peripheral surface and the sheet heating element 2 covering the inner peripheral surface of the other receiving portion 1a, it is preferable to use the metal thin film pattern 2b having the same electrical resistance. Furthermore, it is also possible to use a joint body 1 having a different inner diameter of one receiving portion 1a and another receiving portion 1a.

  In addition, by using the planar heating element 2 as the heating element, a plurality of electric fusion joints 10, 10,... With uniform electrical resistance can be easily manufactured regardless of the shape of the joint body 1. Is possible. That is, in the case of manufacturing a plurality of electric fusion joints 10,... Using a plurality of joint bodies 1,..., The sheet heating element 2 provided in one joint body 1 and the other joint body 1. As for the planar heating element 2 provided on the metal thin film, those having the same electrical resistance of the metal thin film patterns 2b, 2b,. In this way, by adjusting the electric resistance of the metal thin film pattern 2b of the planar heating element 2 regardless of the shape of the joint body 1, current control (resistance value) according to the shape of the joint is performed at the time of fusion work on site. Therefore, the fusion can be completed with the same quality with a constant voltage and current.

  As described above, since the electric fusion joint 10 has few irregularities on the surface of the planar heating element 2, it can be surface-welded to the inserted tube. Therefore, the fusion quality is improved and the occurrence of water leakage trouble can be suppressed. Moreover, since there are few unevenness | corrugations on the surface of the planar heating element 2, generation | occurrence | production of the damage | wound of the surface of the planar heating element 2 is suppressed when a pipe | tube is inserted. Therefore, generation | occurrence | production of the water supply after melt | fusion can be suppressed, and generation | occurrence | production of a water leak trouble can be suppressed. Moreover, the planar heating element 2 can adjust the resistance value easily regardless of the size by adjusting the shape of the metal thin film pattern 2b. Therefore, the control voltage and current can be kept constant during energization, and the control circuit can be simplified. As a result, the fusion quality is greatly improved. Furthermore, the planar heating element 2 can shorten the length of the metal thin film pattern 2b as compared with the heating wire, and there is little change in resistance due to temperature rise due to energization. As a result, it is not necessary to finely change the energization control, and the fusion quality can be easily made constant. As described above, according to the electric fusion joint 10, the fusion temperature and the fusion strength are stable, and a water leakage accident is unlikely to occur.

  The electric fusion joint disclosed in the present application can be widely used, for example, as a joint for connecting a general resin pipe. Specifically, it can be used as a joint for joining a crosslinked thermoplastic resin pipe through which a fluid such as city gas, tap water, or a heating medium for floor heating is passed.

DESCRIPTION OF SYMBOLS 1 Joint main body 1a Receiving part 2 Planar heating element 2a Current supply terminal 2b Metal thin film pattern 2c Insulating film 10 Electric fusion joint

Claims (14)

A joint body having a receiving part, and a sheet heating element covering the inner peripheral surface of the receiving part,
The planar heating element includes an energization terminal, a metal thin film pattern that generates heat by energization through the energization terminal, and an insulating film that covers at least one surface side of the metal thin film pattern and melts by heat generation of the metal thin film pattern. Prepared,
The metal thin film pattern is disposed between the insulating film covering the one surface side and the inner peripheral surface of the receiving portion,
Electric fusion joint. The electric resistance of the metal thin film pattern is 0.1Ω or more and 5.0Ω or less,
The electric fusion joint according to claim 1. The joint body is made of a crosslinked thermoplastic resin,
The insulating film is made of a non-crosslinked thermoplastic resin;
The electrofusion joint according to claim 1 or 2. The metal constituting the metal thin film pattern includes iron or an iron-based alloy,
The electrofusion joint according to any one of claims 1 to 3. The joint body has at least two or more of the receiving portions;
The metal thin film pattern of the planar heating element covering the inner peripheral surface of one of the receiving portions and the metal thin film pattern of the planar heating element covering the inner peripheral surface of the other receiving portion are equivalent to each other. Having resistance,
The electric fusion joint according to any one of claims 1 to 4. The inner diameter of the one receiving portion is different from the inner diameter of the other receiving portion,
The electric fusion joint according to claim 5. For the joint main body having the receiving portion, comprising a step of providing a heating element so as to cover the inner peripheral surface of the receiving portion,
As the heating element, a planar shape including an energizing terminal, a metal thin film pattern that generates heat by energization through the energizing terminal, and an insulating film that covers one surface side of the metal thin film pattern and melts by the heat generation of the metal thin film pattern Using a heating element, the metal thin film pattern is disposed between the insulating film covering the one surface side and the inner peripheral surface of the receiving portion,
A method of manufacturing an electric fusion joint. The electric resistance of the metal thin film pattern is 0.1Ω or more and 5.0Ω or less,
The manufacturing method according to claim 7. Adjusting the shape and / or resistance value of the metal thin film pattern by laser trimming;
The manufacturing method of Claim 7 or 8. Using a joint body made of a crosslinked thermoplastic resin as the joint body,
Using a film made of a non-crosslinked thermoplastic resin as the insulating film,
The manufacturing method of any one of Claims 7-9. As a metal constituting the metal thin film pattern, a metal containing iron or an iron-based alloy is used.
The manufacturing method of any one of Claims 7-10. In the case of providing the planar heating element on the inner peripheral surface of each of the receiving portions for the joint body having at least two receiving portions,
The sheet heating element that covers the inner peripheral surface of one of the receiving portions and the sheet heating element that covers the inner peripheral surface of the other receiving portion have the same electric resistance of the metal thin film pattern. Use
The manufacturing method of any one of Claims 7-11. As the joint body, an inner diameter of the one receiving portion is different from an inner diameter of the other receiving portion.
The manufacturing method according to claim 12. In the case of producing a plurality of electric fusion joints using a plurality of the joint bodies,
For the planar heating element provided in one of the joint bodies and the planar heating element provided in the other coupling body, the metal thin film pattern having the same electrical resistance is used.
The manufacturing method of any one of Claims 7-13.