JP4787628B2 - Electric fusion joint - Google Patents

Description

  The present invention relates to an electric fusion joint provided with an ultraviolet blocking member for preventing deterioration due to ultraviolet rays.

  Conventionally, for example, a pipe member made of a resin having heat melting properties such as polyolefin is known as a pipe member used for a water pipe. Such a pipe member can be fusion-bonded with other polyolefin pipe members, so that the water tightness of the joint portion of both pipe members can be easily secured, but the pipe members are arranged outdoors. There is a problem that it is deteriorated by the ultraviolet rays contained in the sunlight irradiated. Therefore, it has been proposed to provide the tube member with an ultraviolet blocking member for preventing deterioration due to ultraviolet rays so as to cover the outer peripheral surface of the tube member (see, for example, Patent Document 1).

This ultraviolet blocking member is constituted by a heat shrinkable tube made of, for example, soft polyvinyl chloride. The tube member is inserted into the heat-shrinkable tube in a state where the heat-shrinkable tube is not contracted, that is, in an original form, and the heat-shrinkable tube is contracted by heating to be in close contact with the outer peripheral surface of the tube member. Thereby, an ultraviolet blocking layer can be easily formed on the outer peripheral surface of the tube member.
JP 10-267172 A

  By the way, when a polyolefin pipe joint is used to connect each pipe member to each other, in order to prevent deterioration of the pipe joint due to ultraviolet rays, an ultraviolet blocking layer is formed on the outer periphery of the pipe joint in the same manner as formed on the pipe member. It can be considered to form on the surface.

  In this case, when the pipe joint is an electric fusion joint that fuses the joint body and the pipe member inserted into the joint body by energizing a heating wire provided in the tubular joint body, Since each connector pin provided at both ends of the heating wire is provided so as to protrude from the outer peripheral surface of the joint body, an insertion hole for inserting each connector pin is formed in the heat shrink tube in an original state in advance, Each connector pin needs to be inserted into each insertion hole before the contraction tube is contracted.

  However, in general, when a heat-shrinkable tube is heated, the heat-shrinkable tube shrinks in the axial direction and circumferential direction. Therefore, before the heat-shrinkable tube shrinks, the position of each insertion hole corresponds to each connector pin. Even if it is in a proper position, the position of each insertion hole is displaced from an appropriate position due to the shrinkage of the heat shrinkable tube. For this reason, there exists a possibility that a heat contraction tube may be torn by the tensile force which the edge of each insertion hole receives from each connector pin.

  In order to prevent damage to the ultraviolet blocking member, instead of a heat shrinkable tube, it is conceivable to wrap a tape member having ultraviolet blocking properties around the joint body, but it takes time to wrap the tape member around the joint body, Workability is worse than when heat-shrinkable tubes are used.

  Accordingly, an object of the present invention is to provide an electric fusion joint that can easily form the ultraviolet shielding member on the outer peripheral surface of the joint body without causing deterioration of workability and without causing damage to the ultraviolet shielding member. It is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a tubular joint main body into which a pipe member is inserted, the pipe member provided in the joint main body and inserted into the joint main body, An electric fusion joint comprising a heating wire for fusing the joint body with each other, and a pair of connector pins provided at both ends of the heating wire and arranged to protrude from the outer peripheral surface of the joint body, The outer peripheral surface of the joint body is covered with an ultraviolet blocking member that has heat shrinkability and blocks ultraviolet rays from the joint body, and the ultraviolet blocking member includes the ultraviolet blocking member before the ultraviolet blocking member is thermally contracted. A pair of insertion holes through which each connector pin is inserted, and a position for preventing the position of each insertion hole from deviating from an appropriate position corresponding to the connector pin when the ultraviolet blocking member is contracted Slip prevention Means, characterized in that is applied.

Further , the ultraviolet blocking member has a sheet shape and is formed in a cylindrical shape by being wound so as to partially overlap, and the misalignment prevention means overlaps the ultraviolet blocking member. The inserted holes are joined to each other by heat sealing, and the insertion holes are formed in the parts .

According to a second aspect of the present invention, in the first aspect of the invention, the ultraviolet blocking member is made of a material obtained by adding an ultraviolet absorber to a raw material of the same quality as the raw material of the joint body.

According to a third aspect of the present invention, in the second aspect of the present invention, the ultraviolet absorber is carbon black.

  According to the first aspect of the present invention, the position of the pair of insertion holes through which each connector pin is inserted into the ultraviolet blocking member for blocking ultraviolet rays from the joint body corresponds to the connector pin when the ultraviolet blocking member contracts. Since the position shift prevention means for preventing the shift from the proper position is provided, the conventional UV block member by shifting the position of each insertion hole from the proper position when the UV block member is thermally contracted Can be reliably prevented.

  Further, since the outer peripheral surface of the joint body can be easily covered by contracting the ultraviolet shielding member by heating the ultraviolet shielding member, for example, workability by winding a tape member having ultraviolet shielding properties around the joint body. It will not cause any deterioration.

The ultraviolet shielding member is formed in a sheet form, wound so as to partially overlap, in which is formed into a cylindrical shape by the overlapping portions to one another are joined together by thermal fusion For this reason, the overlapping portions of the ultraviolet blocking members joined to each other are thermally contracted in the axial direction and the circumferential direction of the ultraviolet blocking member during the thermal fusion. Accordingly, when the ultraviolet blocking member is heat-shrinked so that the ultraviolet blocking member is brought into close contact with the outer peripheral surface of the joint body by forming each insertion hole at a position corresponding to each connector pin in the overlapping portion that has already been thermally contracted, Since the overlapping portion in which each insertion hole is formed does not shrink, it is possible to reliably prevent each insertion hole from being displaced from the position corresponding to each connector pin when the ultraviolet blocking member is attached to the joint body. it can.

According to invention of Claim 2 , since the raw material of the same quality as the raw material of a joint main body is used for the raw material of an ultraviolet blocking member, when the joint main body is bent or stretched, the ultraviolet blocking member Since the deformation can be caused in the same manner as the joint body, the ultraviolet blocking member can follow the deformation of the joint body. Accordingly, it is possible to prevent the ultraviolet blocking member from being separated from the joint body or damaged due to the deformation of the joint body.

According to the invention described in claim 3 , since carbon black is used as the ultraviolet absorber, the ultraviolet blocking member having the ultraviolet blocking function can be easily obtained by mixing carbon black into the raw material of the ultraviolet blocking member. Can be formed. Further, since carbon black is used as the ultraviolet absorber, for example, the efficiency of absorbing ultraviolet rays contained in sunlight can be improved as compared with the case where a black paint is simply added to the raw material of the ultraviolet blocking member. Therefore, it is possible to more reliably block ultraviolet rays from the joint body.

  The present invention will be described with reference to the illustrated embodiments.

  FIG. 1 shows an example in which the present invention is applied to an electric fusion joint 11 for connecting a plurality of pipe members 10 constituting a pipe line for guiding clean water outdoors.

  In the example shown in FIG. 1, the pipe member 10 according to the present invention has a cylindrical shape, and is formed of a resin that can be easily melted by heating, such as polyolefin such as polyethylene and polypropylene.

  On the outer peripheral surface 10a of each tube member 10, an ultraviolet blocking layer 12 for blocking ultraviolet rays contained in sunlight from each tube member 10 is formed over the entire outer peripheral surface 10a. In the illustrated example, the ultraviolet blocking layer 12 is formed of a material containing carbon black as an ultraviolet absorber in the same polyolefin as the tube member 10. As is well known in the art, carbon black is a fine powder of carbon obtained by incomplete combustion or pyrolysis of natural gas, petroleum and wood.

  An electrofusion joint 11 according to the present invention includes a tubular joint body 13. In the illustrated example, the joint main body 13 is made of polyolefin like each pipe member 10 and has an inner diameter substantially equal to the outer diameter of each pipe member. Further, the joint body 13 has insertion ends 13a into which the end portions 10b of the respective pipe members 10 are inserted at both ends thereof.

  Inside the joint body 13, heating wires 14 are embedded to fuse the joint body and the pipe members 10 inserted into the insertion ends 13 a of the joint body. The heating wire 14 is made of a metal wire made of, for example, nickel chrome, and is wound in a coil shape along the circumferential direction of the joint body 13. At both ends of the heating wire 14, rod-shaped connector pins 15 are provided. The connector pins 15 are arranged on the outer peripheral surface 13b of the joint main body 13 so as to be spaced apart from each other on the same line along the axis of the joint main body 13 and project outward from the outer peripheral surface 13b. , And are accommodated in a pair of cylindrical socket portions 16 provided on the outer peripheral surface 13 b of the joint body 13. As is well known in the art, the heating wire 14 generates heat due to electric power supplied via each connector pin 15.

  In the illustrated example, a pair of bar-shaped indicators 17 indicating that the joint body 13 and the pipe members 10 are appropriately fused are embedded in the joint body 13. Each indicator 17 is arranged on a line passing through each connector pin 15 between each socket portion 16, and is received from each tube member 10 when the joint main body 13 and each tube member 10 are appropriately fused to each other. As shown in FIG. 1, the pressure bulges outward from the outer peripheral surface 13 b of the joint body 13 by the pressure.

  An ultraviolet blocking member 18 for blocking ultraviolet rays from the joint body 13 is provided on the outer peripheral surface 13 b of the joint body 13.

  In the illustrated example, the ultraviolet blocking member 18 is a sheet member having a rectangular plane, and has heat shrinkability. Further, in the illustrated example, the ultraviolet blocking member 18 includes the above-described carbon black in a crosslinked polyethylene which is a raw material having the same properties such as flexibility and stretchability as the raw material of each pipe member 10 and the joint body 13. Molded with material. As shown in FIG. 2, the ultraviolet blocking member 18 is formed in a cylindrical shape having both ends opened by winding the opposite end portions 18 a so as to overlap each other. The ultraviolet blocking member 18 is contracted in the axial direction and the circumferential direction by being heated. In the state before heat shrinkage, that is, the original state, the ultraviolet blocking member 18 has a length dimension along the axis larger than a length dimension along the axis of the joint body 13 and an inner diameter larger than the outer diameter of the joint body 13. Is set to be sufficiently large.

  As shown in FIG. 1, the ultraviolet blocking member 18 is arranged so that its axis coincides with the axis of the joint body 13 and surrounds the joint body 13 from the outer peripheral surface 13b. The main body 13 is in close contact with the outer peripheral surface 13b.

  The overlapping end portions 18a of the ultraviolet blocking member 18 are joined to each other by fusion bonding. As shown in FIG. 1 and FIG. 2, a pair of insertion holes that allow the insertion of the socket portions at positions corresponding to the socket portions 16 formed in the joint body 13, as shown in FIGS. 19 is formed through both end portions 18a. Further, a pair of insertion holes 20 that allow the insertion of the respective indicators are formed in the both end portions 18a at positions corresponding to the respective indicators 17 so as to penetrate the both end portions 18a. The insertion holes 19 and 20 are formed at both ends after the both end portions 18a of the ultraviolet blocking member 18 are fused.

  When forming the electric fusion joint 11, first, the joint body 13 is inserted into the ultraviolet blocking member 18 in its original state. At this time, each socket part 16 formed in the joint body 13 is inserted into each insertion hole 19 formed in the ultraviolet blocking member 18. Next, for example, hot air is applied to the ultraviolet blocking member 18 to heat the ultraviolet blocking member 18, thereby contracting the ultraviolet blocking member 18. At this time, since both end portions 18a of the ultraviolet blocking member 18 are bonded to each other by fusion, the both ends of the ultraviolet blocking member 18 are already contracted in the axial direction and circumferential direction of the ultraviolet blocking member 18 at the time of fusion. Parts other than the part 18a contract. Due to the shrinkage of the ultraviolet blocking member 18, the ultraviolet blocking member comes into close contact with the outer peripheral surface 13 b of the joint body 13. Thereby, the electrofusion joint 11 in which the joint body 13 is covered with the ultraviolet blocking member 18 is formed.

  When the pipe members 10 are connected to each other using the electric fusion joint 11 according to the present invention, the ultraviolet blocking layers 12 at the end portions 10b of the pipe members 10 facing each other are removed from each pipe member by a dedicated cutter (not shown). The outer peripheral surface 10a in the edge part 10b of each pipe member 10 is exposed by cutting along the circumferential direction of 10 and removing. Next, the end portion 10 b where the outer peripheral surface 10 a of each pipe member 10 is exposed is inserted into each insertion end 13 a of the joint body 13. In this state, the heating wire is heated by supplying electric power to the heating wire 14 via each connector pin 15 provided in the joint body 13, and this heat causes the joint body 13 and each pipe member 10 to be mutually connected. Fuse. Thereby, each pipe member 10 is mutually connected via the electric fusion joint 11.

  Thereafter, when the pipe members 10 connected via the electric fusion joint 11 are dragged and moved, the connector pins 15 and the socket portions 16 in which the connector pins are accommodated are respectively connected to the outer periphery of the joint body 13. Cut along the surface 13b and cover the cut surface with, for example, a protective tape (not shown). Thereby, it can prevent that each connector pin 15 and each socket part 16 which protruded from the coupling main body 11 obstruct | occlude the movement of each pipe member 10, respectively.

  According to the present embodiment, as described above, the ultraviolet blocking member 18 is formed in a cylindrical shape by being wound so that both end portions 18a thereof overlap each other and bonded to each other by heat fusion. Therefore, both end portions 18a of the ultraviolet blocking member 18 joined to each other are thermally contracted in the axial direction and the circumferential direction of the ultraviolet blocking member 18 at the time of the thermal fusion.

  Thus, the ultraviolet blocking member 18 is brought into close contact with the outer peripheral surface 13b of the joint body 13 by forming the insertion holes 19 and 20 at the positions corresponding to the connector pins 15 and the indicators 17 in both end portions 18a which have already been thermally contracted. When the heat blocking is performed, the both end portions 18a formed with the insertion holes 19 and 20 of the ultraviolet blocking member 18 are not contracted. Therefore, the insertion holes 19 are mounted when the ultraviolet blocking member 18 is attached to the joint body 13. , 20 can be reliably prevented from being displaced from the positions corresponding to the connector pins 15 and the indicators 17 of the insertion holes 19 and 20 due to the contraction of both end portions 18a.

  Moreover, since the outer peripheral surface 13b of the joint main body 13 can be easily covered by contracting the ultraviolet blocking member 18 by heating the ultraviolet blocking member 18, for example, a tape member having an ultraviolet blocking property is applied to the joint main body 13. Wrapping does not cause deterioration of workability.

  Furthermore, as described above, since the raw material of the same quality as the raw material of the joint body 13 is used as the raw material of the ultraviolet blocking member 18, when the joint body 13 is bent or stretched, the ultraviolet blocking member 18 Similar to the joint body 13, deformation can be caused. Thereby, the ultraviolet blocking member 18 can follow the deformation of the joint body 13. Therefore, it is possible to reliably prevent the ultraviolet blocking member 18 from being separated from or damaged from the joint body 13 due to the deformation of the joint body 13.

  Further, as described above, since carbon black is used as the ultraviolet absorber, carbon black is mixed into the raw materials of the ultraviolet blocking layer 12 and the ultraviolet blocking member 18 formed on the outer peripheral surface 10a of each tube member 10. Accordingly, the ultraviolet blocking layer 12 and the ultraviolet blocking member 18 having an ultraviolet blocking function can be easily formed. Further, since carbon black is used as the ultraviolet absorber, for example, the efficiency of absorbing ultraviolet rays contained in sunlight can be improved as compared with a case where a black paint is simply added to the raw material of the ultraviolet blocking member 18. Therefore, the ultraviolet rays can be more reliably blocked from the joint body 13.

  In this embodiment, the ultraviolet blocking member 18 is made of a sheet member having a rectangular shape, and is wound so that both end portions 18a overlap each other, and the both end portions 18a are joined to each other by thermal fusion to form a cylindrical shape. However, instead of this, the ultraviolet blocking member 18 can be formed of a cylindrical heat-shrinkable tube.

  In this case, when the ultraviolet blocking member 18 is molded, the ultraviolet blocking member 18 can be stretched in the circumferential direction so as to have a large diameter.

  Thereby, when the ultraviolet blocking member 18 is heated when it is mounted on the joint body 13, the residual stress generated in the ultraviolet blocking member 18 is released when the temperature of the ultraviolet blocking member 18 exceeds a predetermined temperature. No. 18 does not contract in the axial direction, but contracts in the direction opposite to the stretched direction, that is, in the direction in which the aperture becomes smaller.

  Further, since each connector pin 15 and each indicator 17 are arranged on the same line along the axis of the joint body 13 as described above, each insertion hole 19, 20 has each connector pin 15 and each indicator 17. Corresponding to the position of the indicator 17, the ultraviolet blocking member is formed along the axis of the joint body 13, that is, the axis of the ultraviolet blocking member 18.

  Therefore, since the ultraviolet blocking member 18 does not contract in the axial direction, the positions of the insertion holes 19 and 20 are shifted from the appropriate positions corresponding to the connector pins 15 and the indicators 17 when the ultraviolet blocking member 18 contracts. It can be surely prevented.

  Further, in the present embodiment, an example in which the ultraviolet blocking member 18 is made of a rectangular sheet member has been shown, but instead of this, an ultraviolet blocking member made of a sheet member having a shape other than the rectangular shape is provided. Can be applied to.

  Furthermore, in the present embodiment, an example is shown in which the length dimension of the ultraviolet blocking member 18 in a sheet shape is set to a length that allows the ultraviolet blocking member 18 to be wound around the joint body 13 so as to make one round of the outer periphery thereof. However, instead of this, the length dimension of the ultraviolet blocking member 18 can be set to a length that allows the outer periphery of the ultraviolet blocking member 18 to be wound around the joint body 13 a plurality of times.

  Further, in the present embodiment, an example in which both end portions 18a of the ultraviolet blocking member 18 are overlapped and joined is shown, but instead of this, portions other than both end portions 18a of the ultraviolet blocking member 18 are overlapped and bonded. be able to.

  Furthermore, in the present embodiment, an example in which the ultraviolet blocking member 18 is made of crosslinked polyethylene has been shown, but instead of this, the ultraviolet blocking member 18 is made of a material other than crosslinked polyethylene such as ethylene propylene rubber, silicon rubber and soft vinyl chloride. Can be formed.

  In the present embodiment, an example in which the present invention is applied to the electric fusion joint 11 for connecting a plurality of pipe members 10 constituting a pipe line for guiding clean water outdoors is shown. Instead, for example, the present invention can be applied to an electric fusion joint that connects a plurality of pipe members constituting a pipe for guiding gas outdoors.

It is a longitudinal section showing roughly the state where pipe members were connected using the electric fusion joint concerning the present invention. It is a perspective view showing roughly the state before heat contraction of the ultraviolet blocking member concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pipe member 11 Electric fusion joint 13 Joint main body 13b Outer peripheral surface (outer peripheral surface of joint main body)
14 Heating wire 15 Connector pin 18 UV blocking member 19 Insertion hole

Claims (3)

A tubular joint body into which a pipe member is inserted, a heating wire provided in the joint body, and the tube member inserted into the joint body and the joint body are fused together, and the heating wire And a pair of connector pins disposed so as to protrude from the outer peripheral surface of the joint main body, wherein the outer peripheral surface of the joint main body has heat shrinkability from the joint main body. The ultraviolet blocking member is covered with an ultraviolet blocking member for blocking ultraviolet rays, and the ultraviolet blocking member is formed with a pair of insertion holes through which the connector pins are inserted before the ultraviolet blocking member is thermally contracted. In addition, when the ultraviolet blocking member is contracted, a position shift prevention means is provided for preventing the position of each insertion hole from shifting from an appropriate position corresponding to the connector pin.
The ultraviolet blocking member has a sheet shape and is formed in a cylindrical shape by being wound so as to partially overlap, and the positional deviation prevention means is an overlapping portion of the ultraviolet blocking member Each of the insertion holes is formed in the portion after joining them together by heat fusion.   The electrofusion joint according to claim 1, wherein the ultraviolet blocking member is made of a material obtained by adding an ultraviolet absorber to a raw material of the same quality as the raw material of the joint body. The electrofusion joint according to claim 2 , wherein the ultraviolet absorber is carbon black.

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