JP2016033391A - Connection method of resin pipe and resin joint, and piping unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection method of a resin pipe and a resin joint capable of reducing manufacturing costs and construction costs of the joint, and further ensuring connection, in the connection method for connecting the pipe and the joint composed of a crosslinked thermoplastic resin.SOLUTION: In a connection method of a resin pipe and a resin joint, the joint 2 having a connection port 3 for inserting the pipe 1 at least at one end, and provided with an adhesive ring 6 disposed on an inner peripheral portion at a connection port side and composed of a resin composition in which 10-90 wt.% of ethylene polymer and/or ethylene copolymer is blended to a modified polyethylene copolymer having adhesive property, is used as the joint. An end portion of the pipe 1 is inserted to the connection port 3 of the joint 2, and a region corresponding to a pipe inserting part is heated from an outer peripheral side of the joint 2 to melt the adhesive ring 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connection method and a piping unit between a resin pipe and a resin joint, and more specifically, a connection method for connecting a pipe and a joint made of a crosslinked thermoplastic resin by heating, and a configuration using the connection method. It is related with the connected piping unit for connection.

  In hot water supply facilities and solar collectors, as a pipe for water supply and hot water supply, from the viewpoint of durability and cost, instead of the conventional copper pipe, a pipe made of a crosslinked thermoplastic resin tends to be used. In such a connection portion between the tubes, a joint made of the same material as the tube is used.

  As a joint attached to a pipe made of the above-mentioned crosslinked thermoplastic resin, an adhesive ring (resin layer) is arranged in advance on the inner peripheral portion on the connection port side where the pipe is inserted, and a coil that generates heat when energized is used as the adhesive ring. An electric heating type joint called an “electrofusion joint” is proposed. In such a joint, the above-mentioned adhesive ring is obtained by spirally winding a heating wire coated with a specific resin and integrating it into a cylindrical shape, and the resin of the adhesive ring has an adhesive property. It is comprised from the resin composition which mix | blended 10-90weight% of ethylene polymer and / or ethylene copolymer with the modified polyethylene copolymer which has. And when connecting the joint to the pipe, the adhesive ring is melted by heating the coil to a predetermined temperature, and the outer peripheral part of the pipe and the joint body (outer shell) are softened. The adhesive ring is fused and integrated, and at the same time, the joint body and the adhesive ring are fused and integrated.

Japanese Patent No. 4772174

  By the way, the method of energizing the coil inside the joint and fusing the joint to the pipe uses an adhesive ring in which the coil is previously embedded, so that there is a problem that it is difficult to reduce the cost of the joint itself. In addition, a controller for controlling the heat generation temperature of the coil in accordance with the specification of the coil is necessary, and the construction becomes large and leads to an increase in cost.

  Moreover, in the above-mentioned electric heating type joint, the coil of the adhesive ring is embedded in a state where the heating wire is not bonded to the coating resin in order to connect to the terminal on the controller side, and when the electric heating is performed In some cases, the heating wire constituting the coil floats, breaks through the coating resin, and the heating wire is exposed to the water channel. As a result, water may leak during use.

  The present invention has been made in view of the above circumstances, and an object thereof is a connection method for connecting a joint made of a crosslinked thermoplastic resin to an end portion of a pipe made of the crosslinked thermoplastic resin, and manufacturing the joint It is an object of the present invention to provide a method for connecting a resin pipe and a resin joint, which can reduce the cost and the construction cost, and can be more reliably connected without occurrence of cracks in the coating resin at the time of fusion. Another object of the present invention is to provide a connecting piping unit in which a joint is connected to an end of a pipe by the above connection method.

  In order to solve the above-mentioned problems, with regard to conventional electric heating type joints, many analyzes were made of the fused state of the adhesive ring placed on the inner periphery of the joint and the fused state of the adhesive ring to the pipe and joint body. As a result, it was confirmed that the coil embedded in the adhesive ring tends to inhibit the fusion between the resins. Conventionally, it was assumed that the resin could be fused by melting the adhesive ring by embedding the coil in advance in the adhesive ring. If an adhesive ring with a structure that is not used is placed on the inner circumference of the joint, the part corresponding to the pipe insertion part is heated from the outer circumference of the joint, and the heating conditions are devised, the adhesive ring is surprisingly sufficient. It was found that the resin can be melted and the outer periphery of the tube and the joint body can be softened to fuse the resins together, thereby completing the present invention.

  That is, the gist of the present invention is a method of connecting a joint made of a crosslinked thermoplastic resin to an end portion of a pipe made of a crosslinked thermoplastic resin, wherein the joint is provided with a connection port for inserting the pipe at least at one end; An adhesive ring is arranged on the inner peripheral portion on the connection port side, and the adhesive ring is blended with 10 to 90% by weight of ethylene polymer and / or ethylene copolymer in the modified polyethylene copolymer having adhesiveness. Characterized in that a joint made of the resin composition is used, the end of the pipe is inserted into the joint connection port, and the part corresponding to the pipe insertion part is heated from the outer peripheral side of the joint to melt the adhesive ring. The method is to connect the resin pipe and the resin joint.

  According to the present invention, a coil is not used for the joint, and a controller for heat generation control is not necessary for heating. Therefore, the manufacturing cost of the joint can be reduced, and the construction cost can be reduced. In addition, when the adhesive ring is in direct contact with the joint body and the pipe without any foreign matter such as a coil, the adhesive ring inside the joint is melted by heating from the outer circumference side of the joint. The fused surface of the adhesive ring, the inner peripheral part of the joint body and the fused surface of the adhesive ring are reliably integrated, and there is no occurrence of cracks in the fused portion, and a higher quality connection is possible.

It is sectional drawing which shows the connection structure of an example of the resin coupling used for this invention, and a resin pipe. It is sectional drawing which shows the connection structure of the other example of the resin coupling used for this invention, and a resin pipe. It is a side view which shows an example of the piping unit for connection produced using the connection method of this invention. It is a perspective view which shows the usage example of the resin coupling of FIGS.

  An embodiment of a method for connecting a resin pipe and a resin joint according to the present invention and an embodiment of a connecting piping unit will be described with reference to the drawings. In the figure, reference numeral 1 represents a tube, reference numeral 2 (2A, 2B) represents a joint, and reference numeral 6 represents an adhesive ring. In addition, this invention is not limited to the following embodiment, unless the meaning is exceeded.

  The connection method of the present invention is a method of connecting a joint 2 made of a crosslinked thermoplastic resin to an end portion of a pipe 1 made of a crosslinked thermoplastic resin. For example, as shown in FIG. A joint in which a connection port 3 for inserting 1 is provided and an adhesive ring 6 is disposed on the inner peripheral portion on the connection port side is used.

  A typical example of the crosslinked thermoplastic resin constituting the tube 1 and the joint 2 is crosslinked polyethylene. The pipe 1 is manufactured by ordinary extrusion molding, and the joint 2 is manufactured by mounting a molded adhesive ring 6 on a core and injection molding. As the tube 1, a tube having an outer diameter of about 10 to 34 mm and a thickness of about 1.6 to 4.0 mm is used. For example, when the name is 13A, the tube 1 has an outer diameter of 17 mm and a wall thickness of 2.1 mm. When the name is 20A, the pipe 1 has an outer diameter of 27 mm and a wall thickness of 3.25 mm.

  The joint 2 may have a structure in which the pipe 1 is connected to both ends. For example, as shown in FIG. 1, the joint 2 is provided with a connection port 3 for inserting the pipe 1 at one end (the right end in the drawing) and the other end. A connecting portion (coupler) 4 is provided at the left end in the drawing. That is, the illustrated joint 2 includes a cylindrical joint body 30 into which the pipe 1 is inserted from the connection port 3 on one end side, a female connecting portion 4 provided on the other end side of the joint body, and a joint body 30. It is comprised from the adhesive ring 6 arrange | positioned at the inner peripheral part. At the back end of the joint body 30 (back end of the connecting portion 4), a butting portion 31 formed in a small diameter portion is provided, and the butting portion 31 is the pipe 1 inserted into the joint body 30. Is a portion where a male connecting portion (coupler) 5 (see FIG. 4) inserted into the connecting portion 4 hits.

  Further, the joint 2 may be a joint having a structure shown in FIG. The joint 2 shown in FIG. 2 has a double pipe structure in which an inner pipe 32 is provided on the connection port 3 side, that is, on the inner peripheral side of the joint body 30, and a gap between the inner pipe 32 and the adhesive ring 6. It is comprised so that the edge part of the pipe | tube 1 may be inserted in. In such a joint 2, since the inner pipe 32 is provided, the joint 2 is made more stable when the distal end of the pipe 1 is relatively inserted in heating construction, and the softened pipe 1 is bonded to the adhesive ring 6. It is possible to prevent deformation due to expansion of the inside.

  In the joint 2, the thickness on the connection port 3 side, that is, the thickness of the joint body 30 excluding the thickness of the adhesive ring 6 is about 1.5 to 3 mm in consideration of strength and workability during heating operation. And is set to 1.5 to 2 mm when applied to the tube 1 of 13A and 2.5 to 3 mm when applied to the tube 1 of 20A.

  The adhesive ring 6 is produced, for example, by being extruded into a tubular shape and then cut into a predetermined length. As described above, the adhesive ring 6 is inserted into the mold when the joint 2 is injection-molded. Thereby, it can arrange | position to the inner peripheral part by the side of the connection port 3 of the coupling 2, ie, the inner peripheral part of the coupling main body 30. FIG. The inner diameter of the adhesive ring 6 is designed to fit the tube 1, and the thickness of the adhesive ring 6 is about 0.8 to 1.8 mm when applied to the 13 A tube 1. It is set to 1.4 to 1.6 mm when applied to the tube 1 of .about.1.5 mm and 20A.

  The adhesive ring 6 is composed of a resin composition in which 10 to 90% by weight of an ethylene polymer and / or an ethylene copolymer is blended with a modified polyethylene copolymer having adhesiveness. That is, the adhesive ring 6 is melted at a temperature lower than that of the crosslinked thermoplastic resin of the tube 1 and the joint 2, and when this is heated and melted, it is entangled with the crosslinked structure of the crosslinked thermoplastic resin constituting the tube 1 and the joint 2. And made of polyethylene that is integrated with the resin of the pipe 1 and the joint 2. A specific composition of the adhesive ring 6 is disclosed in Japanese Patent No. 4772174.

  In the connection method of the present invention, as shown in FIGS. 1 and 2, the end of the pipe 1 is inserted into the connection port 3 of the joint 2, and a portion corresponding to the pipe insertion portion is heated from the outer peripheral side of the joint 2. To melt the adhesive ring 6. That is, heating is performed from the outer peripheral side of the joint body 30 of the joint 2 in a state where the joint 2 is temporarily attached to the tip of the pipe 1. A symbol C in the figure represents a heating zone in the joint 2.

  In the above heating operation, it is important to heat the adhesive ring 6 so as to melt the tube 1 and the joint 2 (joint body 30). In other words, in this invention, it heats more than the melting temperature of the adhesive ring 6 and less than the melting temperature of the joint 2 and the pipe 1. As a result, the melted resin of the adhesive ring 6 is entangled with the resin cross-linking structure on the outer periphery of the tube 1 and the resin cross-linking structure on the inner peripheral portion of the joint 2 (joint body 30). 6 can be fused and integrated, and the adhesive ring 6 and the joint body 30 can be fused and integrated.

  As a method for heating the joint 2 from the outer peripheral side, for example, a hot air generator such as an industrial dryer can be used. In this case, although not shown, a metal band-shaped shroud curved in an arc shape is attached to the outlet of the hot air generator, and the joint body 30 of the joint 2 is surrounded by the shroud and is not attached to the joint body 30. Hot air may be blown by contact. The heating method using a hot air generator is excellent in that it can be easily constructed on site.

  Further, as another method of heating the joint 2 from the outer peripheral side, a method of heating by attaching a band heater to the outer peripheral portion of the joint main body 30 of the joint 2 can be mentioned. The band heater has a structure in which a heating wire such as a heat-resistant nickel chrome ribbon wire is sealed with an insulating material such as mica and the outside is covered with a metal plate, and the heating portion is formed in a short-axis cylindrical shape. Since the heating method using a band heater can keep the heater temperature constant, a higher-quality connection can be made. Furthermore, in the case where a large number of parts such as a connecting piping unit to be described later are manufactured, the heat treatment can be efficiently performed by passing through a heating furnace while continuously conveying.

  In the heating operation, heating is performed at a temperature equal to or higher than the melting temperature of the adhesive ring 6 and the softening temperature of the joint 2 and the tube 1. Specifically, when the thickness of the joint 2 on the connection port 3 side is 1.5 to 3 mm and the thickness of the adhesive ring 6 is 0.8 to 1.8 mm, the outer circumference of the joint 2 is 250 to 350 ° C. ( Heater temperature), preferably at about 300 ° C. for 20 to 60 seconds, preferably 30 to 50 seconds. By heating with the heater temperature set in the above range, the temperature in the vicinity of the center of the adhesive ring 6 inside the joint 2 is raised to 120 to 160 ° C., preferably about 140 ° C. And in order to fuse | melt the adhesive ring 6 reliably with respect to the outer peripheral part of the pipe | tube 1 and the inner peripheral part of the coupling main body 30, heating time is set to 30 to 60 second, Preferably it is 30 second or more. In addition, after a heating, a connection part is naturally cooled or it blows cold air and is forcedly cooled.

  As described above, in the connection method of the present invention, no coil is used for the joint 2, and no controller for heat generation control is required for heating, so the manufacturing cost of the joint 2 can be reduced and the construction cost can be reduced. it can. Further, in a state where the adhesive ring 6 is in direct contact with the joint body 30 and the pipe 1 of the joint 2 without any foreign matter such as a coil, the adhesive ring 6 inside the joint is melted by heating from the outer peripheral side of the joint 2. Therefore, the outer peripheral portion of the tube 1 and the fused surface of the adhesive ring 6 and the inner peripheral portion of the joint body 30 and the fused surface of the adhesive ring 6 are reliably integrated, and cracks are generated in the fused portion. Therefore, a higher quality connection is possible.

  Moreover, the connection piping unit can be produced in advance using the connection method of the present invention. The connecting piping unit is a part used for connecting a circulating piping in a hot water supply apparatus, for example. For example, as shown in FIG. 3, the pipe unit is formed in a substantially Z shape by bending both ends of the pipe 1 in directions opposite to each other, and a joint 2 </ b> A and a joint 2 </ b> B are attached to both ends of the pipe 1. ing. In other words, the joints 2A and 2B made of a crosslinked thermoplastic resin are connected to the end portion of the tube 1 made of the crosslinked thermoplastic resin. And these joints 2A and 2B are provided with the connection structure shown in FIG. 1 or FIG. 2, and are connected to the pipe | tube 1 by the connection method of this invention. In other words, in the joints 2A and 2B, the outer peripheral portion of the end portion of the pipe 1 and the adhesive ring 6 are fused, and the joint body 30 and the adhesive ring 6 of the joints 2A and 2B are fused. .

  As the joint 2 applied to the above-described piping unit, for example, as shown in FIG. 3, a female joint 2A is used at one end of the pipe 1, and a male joint 2B is used at the other end. As shown in FIG. 4, these joints 2 </ b> A and 2 </ b> B are joints having a structure that can be connected to each other, and are used for connecting pipes. That is, in coupling of the joints 2A and 2B, by inserting the coupling part 5 of the cylindrical structure of the joint 2B into the coupling part 4 of the cup structure of the coupling 2A, The flange portions provided at the central portion of 2B are overlapped, and then these flange portions are fastened with clips 7. An O-ring 51 is attached to the connecting portion 5 of the male joint 2B.

  The clip 7 is made by punching a metal strip and bending it, and is bent into a substantially Ω shape at the center of the length. Each curved piece has a length along the length. A long hole is opened. When the clip 7 is used, the joints 2A and 2B can be coupled by simply sandwiching the flanges of the joints 2A and 2B from the outer periphery so as to fit into the elongated holes. By preparing the piping unit as described above in advance, the manufacturing process of equipment such as a hot water supply device can be greatly simplified.

  Also in the above piping unit, since the joints 2A and 2B are connected by the connection method of the present invention, the manufacturing cost of the piping unit can be further reduced. And, since the outer peripheral portion of the tube 1 and the fused surface of the adhesive ring 6, the inner peripheral portion of the joint body 30 and the fused surface of the adhesive ring 6 are reliably integrated, there is no occurrence of cracks in the fused portion, There is no risk of water leakage, and the quality of equipment such as a hot water supply device can be further enhanced.

  According to the connection method of the present invention, a joint 2 having a structure shown in FIG. 1 made of crosslinked polyethylene was connected to the tip of a tube 1 made of crosslinked polyethylene to produce a molded product. At that time, a plurality of molded articles were prepared by changing the heater temperature and heating time. Then, the obtained molded product was subjected to a hot internal pressure creep test to confirm the strength.

  As the tube 1, two types of tubes having the names 13A and 20A were used. An industrial dryer (made by HAKKO: Model 882) is used as a heater for heating the joint 2, the heating temperature is set to 100 to 450 ° C., and the heating time is set to 20 to 60 seconds. Set. The hot internal pressure creep test was performed according to JIS K6769 (2004 edition) “Appendix 2”, and the temperature in that case was set to 95 ° C. by heating in an oven.

  The results of the hot internal pressure creep test are as shown in the following table. In the table, the symbol “◎” indicates that the sample has passed the hot internal pressure creep test with a circumferential stress of 4.4 MPa · 1000 hours, and the symbol “◯”. Indicates a sample that passed the hot internal pressure creep test with a circumferential stress of 4.8 MPa · 1 hour, and the symbol “x” represents a sample that failed. As a result of the test, it was confirmed that the strength of the connecting portion between the pipe 1 and the joint 2 was ensured by setting the heating temperature to 250 to 350 ° C. and the heating time to 30 to 60 seconds. Moreover, about the molded product which passed the hot internal pressure creep test, when fracture | ruptured and the fusion | melting part inside the joint 2 was confirmed visually, generation | occurrence | production of a crack was not confirmed.

1: Pipe 2: Joint 2A: Joint (female joint)
2B: Joint (male joint)
3: Connection port 30: Joint main body 31: Abutting part 32: Inner pipe 4: Connection part (female)
5: Connection part (male)
51: O-ring 6: Adhesive ring 7: Clip C: Heating zone

Claims (7)

  A method of connecting a joint made of a crosslinked thermoplastic resin to an end of a pipe made of a crosslinked thermoplastic resin, wherein the joint is provided with a connection port for inserting the pipe at least at one end, and an inner peripheral part on the side of the connection port An adhesive ring is disposed on the joint, and the adhesive ring includes a joint made of a resin composition in which 10 to 90% by weight of an ethylene polymer and / or an ethylene copolymer is blended with a modified polyethylene copolymer having adhesiveness. The connection between the resin pipe and the resin joint is characterized in that the end of the pipe is inserted into the connection port of the joint and the part corresponding to the pipe insertion part is heated from the outer peripheral side of the joint to melt the adhesive ring. Method.   The connection method according to claim 1, wherein heating is performed at a temperature equal to or higher than a melting temperature of the adhesive ring and lower than a melting temperature of the joint and the pipe.   The connection method according to claim 1 or 2, wherein hot air is blown to the outer periphery of the joint to heat the joint.   The connection method according to claim 1 or 2, wherein a band heater is attached to the outer peripheral portion of the joint for heating.   The thickness of the joint on the connection port side is 1.5 to 3 mm, the thickness of the adhesive ring is 0.8 to 1.8 mm, and heating is performed at 250 to 350 ° C for 30 to 60 seconds from the outer periphery of the joint. The connection method in any one of -4.   The joint is provided with a double pipe structure in which an inner pipe is provided on a connection port side, and is configured to insert an end of the pipe into a gap between the inner pipe and the adhesive ring. The connection method according to the above.   It is the piping unit for connection comprised by connecting the joint which consists of a crosslinked thermoplastic resin to the edge part of the pipe | tube which consists of a crosslinked thermoplastic resin, Comprising: A pipe | tube unit by the connection method in any one of Claims 1-6 A piping unit, wherein a joint is connected, an outer peripheral portion of an end of a pipe and an adhesive ring are fused, and a main body of the joint and an adhesive ring are fused.

Images