JP2007100952A - Connecting method of thermoplastic resin pipe, pipe set for connection and pipe for connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting method of thermoplastic resin pipes, and a pipe set for connection used in the connecting method, capable of easily connecting a thermoplastic resin connecting pipe and a thermoplastic resin connected pipe even when diameters of the pipes are extra-large. <P>SOLUTION: Problems can be solved by providing the connecting method of the thermoplastic resin pipes and the pipe set for connection, wherein an outer peripheral face of a spigot 10 of the connected pipe B is preheated by a preheating heater to be softened, or expanded by being softened, and a spigot 10 of the connecting pipe A is inserted into and connected to the socket 20 of the connected pipe B, when the thermoplastic resin connecting pipe A having the spigot 10 at least at its one end, and the thermoplastic resin connected pipe B having the socket 20 at least at its one end are connected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a connection method and a connection structure for a thermoplastic resin pipe, and more specifically, connects a thermoplastic resin connection pipe having an inlet at one end and a thermoplastic resin connected pipe having a receptacle at one end. The present invention relates to a connecting method and a connecting structure of a thermoplastic resin pipe.

  In this type of thermoplastic resin pipe connection method, the pipe to be connected is usually set so that the outer diameter of the receiving port is substantially the same as or slightly larger than the inner diameter of the connecting pipe. For example, the diameter of the pipe is about 200 mm or more. In the case of a large pipe, the connection work is difficult. In this case, in order to make it easy to insert the insertion port (connection part) of the connection pipe, the receiving port (connection part) of the pipe to be connected is flanged with a tool on site. The diameter was expanded. Then, the connecting pipe insertion port is inserted into and joined to the connected pipe receiving port, and in some cases, a heating wire is disposed between the receiving port and the connecting port to energize the bonding portion between the receiving port and the inserting port. The connection was made (see, for example, Patent Document 1).

When connecting the connecting pipe and the connected pipe, the work of expanding the diameter of the receiving port of the connected pipe in a flange shape as described above is not easy even if it is performed in the factory as well as in the field. In particular, in order to prevent liquid leakage from the connection part, it is necessary to expand the diameter of the connected pipe so that the insertion opening and the receiving opening of the pipe fit in a predetermined gap, and the connected pipe has a diameter of about 200 to 3000 mm. In the case of a large diameter, the diameter expansion workability was extremely poor.
JP 2002-122282 A

  Accordingly, one of the main objects of the present invention is a method for connecting a thermoplastic resin pipe that can easily connect a connecting pipe and a connected pipe, a connecting pipe set used for the connecting method, and a connecting pipe. Is to provide a tube.

Thus, according to the present invention, when connecting the connecting pipe made of thermoplastic resin having at least one opening to the connecting pipe made of thermoplastic resin having at least one end, the outer periphery of the receiving opening of the connecting pipe A thermoplastic resin pipe connection method is provided in which a surface is softened by preheating with a preheating heater, or softened or expanded in diameter, and a connection pipe insertion port is inserted into a connection port of a connected pipe for connection.
Further, according to another aspect of the present invention, there is provided a connection tube set used in the method for connecting the thermoplastic resin pipes, the thermoplastic resin connection pipe having an opening at least at one end thereof, and this connection A connecting pipe made of thermoplastic resin having at least one receiving opening into which the insertion opening of the pipe is inserted, and the inner diameter of the receiving opening of the connecting pipe is equal to or smaller than the outer diameter of the insertion opening of the connecting pipe A set of configured connection pipes is provided.
Further, according to another aspect of the present invention, the connecting pipe has a receiving port having the same shape and size as the receiving port of the connected tube at the other end, and the connected tube has the same shape and size as the inserting port of the connecting tube at the other end. A connecting pipe set including a connecting pipe set having a spigot and a thermoplastic resin connecting pipe is provided.

According to the thermoplastic resin pipe connection method of the present invention, by preheating the outer peripheral surface of the receiving port of the connected pipe, the outer peripheral surface of the receiving port becomes hotter than the inner peripheral surface, and the outer peripheral surface side becomes soft and elastic. The rate drops. As a result, a force acts in the direction in which the diameter of the receptacle naturally expands, and the inner diameter and the outer diameter increase. That is, it utilizes the characteristics of a thermoplastic resin having low thermal conductivity and the thermal deformability of the thermoplastic resin by preheating from one direction.
Therefore, first, when the inner diameter of the receiving port of the pipe to be connected is the same as or smaller than the outer diameter of the inlet of the connecting pipe, secondly, in construction in a cold district where the outside air temperature is low, the diameter of the receiving port is expanded by elastic deformation. Thirdly, when it is difficult to connect, even when connecting a thermoplastic resin pipe having a large diameter of, for example, 200 mm or more, which makes connection work difficult, according to the present invention, the connection pipe can be easily inserted. Can be inserted and connected to the receptacle of the connected pipe.
In addition, if the preheating to the receiving port of the connected tube is stopped after connecting the connecting tube and the connected tube, the diameter of the receiving port is reduced in the course of natural cooling. The gap between the two is reduced, and the connection becomes stronger.
Further, according to the present invention, if the outer peripheral surface of the receiving port of the connected tube is softened, the insertion port of the connecting tube can be inserted into the receiving port of the connected tube without increasing the inner diameter. In this case, a reverse tapered surface portion is formed on the inner peripheral surface side of the open end of the receiving port of the connected pipe, and further, a tapered surface portion is formed at the distal end of the connecting tube, and the tapered surface portion of the receiving port is the reverse tapered surface portion of the receiving port. By pressing and sliding on, the receptacle can be expanded and the insertion slot can be easily inserted.
Needless to say, this connection method is applicable even when the inner diameter of the receiving port of the pipe to be connected is larger than the outer diameter of the outlet of the connecting pipe.

  Further, the connection pipe set and the connection pipe of the present invention in which the inner diameter of the connection pipe receiving port is set to be equal to or smaller than the outer diameter of the connection pipe insertion port, the thermoplastic resin pipe connection method Therefore, the diameter of the inner diameter is not specified with high accuracy when forming the receiving port of the connected pipe, and the forming of the receiving port can be facilitated, and the outer diameter of the connecting pipe is made larger than the outer diameter. The material cost can be reduced as compared with the case.

The method for connecting a thermoplastic resin pipe according to the present invention comprises the step of connecting the thermoplastic resin connecting pipe having an insertion opening at least at one end and the thermoplastic resin connecting pipe having a receiving opening at least at one end. The outer peripheral surface of the pipe receiving port is softened by preheating with a preheating heater, or is softened / expanded, and the connection port is inserted into the receiving port of the connected pipe and connected.
The connection pipe set used in this connection method includes a thermoplastic resin connection pipe having an insertion opening at least at one end, and a thermoplastic resin coating having at least one receiving opening into which the insertion opening of the connection pipe is inserted. And an inner diameter of the receiving port of the connected tube is set to be equal to or smaller than an outer diameter of the insertion port of the connecting tube.
Here, in the present invention, the inner diameter of the receiving port of the pipe to be connected means the inner diameter of the opening end of the receiving port, and the outer diameter of the inlet of the connecting pipe means the outer diameter of the tip of the opening. .
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating the present embodiment.

(Embodiment 1)
FIG. 1 is a partial cross-sectional view showing a receiving port and an insertion port of a connecting tube set according to Embodiment 1 of the present invention. In FIG. 1, symbol A represents a connecting pipe having an outlet 10 at one end, and symbol B represents a connected pipe having a receiving port 20 at one end. The connecting pipe A and the connected pipe B are made of a flexible resin such as polyethylene resin or polypropylene resin, and examples of uses thereof include a water and sewage pipe, a drainage pipe, and a water intake pipe.

  In the connection pipe A, the insertion port 10 having an inner diameter of the same size as the inner diameter of the body 11 is connected to one end of the cylindrical body 11. The insertion slot 10 has a first tapered surface portion 12 that is reduced in diameter toward the tip on the outer peripheral surface, and a second tapered surface portion 13 that is further reduced in diameter at the tip of the first tapered surface portion 12. ing. The taper angle θ with respect to the axis of the first tapered surface portion 12 is, for example, 1 to 3 °. The first and second tapered surface portions 12 and 13 are formed on the site by using a cutting blade whose operation is controlled so as to be inclined and cut at a certain angle from the outer periphery of the insertion port 10 to a point on the shaft. Or it is performed in the factory beforehand.

In the present invention, the outer diameter D ₁ of the insertion port 10 of the connecting pipe A means the outer diameter of the distal end portion of the insertion port 10 as described above, and is first when the distal end has a tapered surface portion as shown in FIG. And the outer diameter between the second tapered surface portions 12 and 13.
Further, as shown in FIG. 2, the connecting pipe A is a double body in which the corrugated outer pipe portion 14 formed by alternately arranging the crest portions 14 a and the trough portions 14 b on the outer peripheral surface of the trunk portion 11 is integrally formed. It may be a tube structure. In this case, the material of the corrugated outer tube portion 14 is a thermoplastic resin, preferably the same material as that of the body portion 11.

In the connected pipe B, the receiving port 20 having an inner diameter d ₁ larger than the inner diameter of the trunk portion 21 is connected to one end of a cylindrical barrel portion 21. The inner peripheral surface of the receiving port 20 is formed in parallel with the same diameter or in a reverse taper shape with a taper angle θ or less of the connecting pipe A, and the inner diameter d ₁ is the outer diameter D of the outlet 10 of the connecting pipe A. It is set equal to or smaller than ₁ . That is, it is expressed by d ₁ ≦ D ₁ .

The receiving port 20 of the connected pipe B has a first reverse tapered surface portion 22 whose diameter increases toward the tip on the inner peripheral surface of the opening end, and the connecting pipe A is covered at the inner end. When inserted into the connecting pipe B, the second taper surface portion 13 has a second reverse taper surface portion 23 that can come into surface contact.
Further, a concave circumferential groove 24 is formed closer to the tip than the intermediate position in the axial center direction of the outer peripheral surface of the receiving port 20 of the connected pipe B. This concave circumferential groove 24 is a groove for mounting the fastening ring 30 shown in FIG. 3 for fastening the receiving port 20 of the connected tube B into which the insertion port 10 of the connecting tube A is inserted. The tightening ring 30 will be described in detail later.
Similarly to the connecting pipe A, the connected pipe B is a double pipe in which a corrugated outer pipe portion formed by alternately connecting peaks and valleys on the outer peripheral surface of the trunk portion 21 is formed integrally. It may be present (see FIG. 2).

  As shown in FIGS. 1 and 4, the pipe B is made of a strip-shaped thermoplastic resin having a length substantially equal to the peripheral length of the inner peripheral surface of the receiving port 20 at a substantially intermediate position in the axial direction of the inner peripheral surface of the receiving port 20 in the connected pipe B. A fusion heater 40 including a sheet 41 and a heating wire 42 meandering in the longitudinal direction may be wound on or inside the sheet 41. The material of the sheet 41 is preferably the same thermoplastic resin as the connecting pipe A and the connected pipe B, and the thickness is suitably 1 to 3 mm. In the fusion heater 40 wound around the inner peripheral surface of the receiving port 20 of the connected pipe B, a pair of energizing terminals 42 a at both ends of the heating wire 42 extend from the receiving port 20 to the outside. In addition, in order to hold | maintain a winding state, you may temporarily fix | stop by simple welding or electricity supply.

  The heating wire 42 is not particularly limited, but a heating wire made of brass, zinc or the like having a wire resistance of about 5.5 to 7.0 μΩcm is preferable. Particularly, brass is rich in ductility and malleability due to its material properties. It is preferable from the viewpoint that it can be easily bent and has good corrosion resistance. In the case of a brass wire, as shown in FIG. 5, from the viewpoint that it is possible to give rigidity suitable for workability in the case of being bent and formed in a meandering manner and prevention of short-circuiting (short-circuiting) between bent heating wires. The diameter is preferably 1.5 to 2.5 mmφ, and more preferably about 2.0 mmφ. In addition, when the heating wire is a brass wire having a wire diameter of 1.5 to 2.5 mm, the pitch p is 16.0 to 23.0 mm and the width w is 50 to 70 mm. It is preferable to set.

In the state where the connecting pipe A is inserted into the connected pipe B, the heating wire 42 of the fusion heater 40 is energized at a low voltage (for example, 13 V) to generate heat at 160 to 220 ° C., together with the thermoplastic resin sheet 41. The tapered surface portion 12 of the insertion port 10 in the vicinity thereof and the inner peripheral surface of the receiving port 20 can be melted, and the connecting pipe A and the connected pipe B can be fused and integrated. By forming the heating wire 42 in a meandering manner, heat can be uniformly conducted to the joint portion, and a strong connection structure having the heating wire 42 as a framework in the connection portion where the connecting pipe A and the connection pipe B are fused and integrated. Is obtained.
The fusion heater 40 may be wound around the tapered surface portion 12 of the outer peripheral surface of the insertion port 10 of the connection pipe A. In this case, the pair of energization terminals 42 a of the heating wire 42 may be led out from the gap between the connecting pipe A and the connected pipe B. Further, if the thermoplastic resin sheet 41 is formed in a slightly arcuate shape, the sheet 41 can be wound around the tapered surface portion 12 in a frustoconical shape without any gap. Further, the heating heater 42 is sandwiched between two belt-like heat-shrinkable sheets (for example, polyethylene resin sheets), and the fusion heater formed by heat-shrinking is tightly held on the tapered surface portion 12 of the inlet 10 of the connecting pipe A. Also good.

In such a connection pipe set consisting of the connection pipe A and the connection pipe B, as shown in FIG. 6, the connection pipe A is connected to the receiving port 20 (FIG. 1) of the connection pipe B at the other end opposite to the insertion port 10. The connection pipe B may have an insertion port 28 having the same shape and dimension as the insertion port 10 of the connection pipe A at the other end opposite to the reception port 20. That is, the entire configuration of the connecting pipe A and the connected pipe B may be the same. Furthermore, the connecting pipe A and the connected pipe B having the same configuration may have a double pipe structure as shown in FIG.
By making the connecting pipe A and the connected pipe B the same pipe, it is possible to adjust the length by connecting a plurality of pipes as well as the use of connecting at a specific location in the field. It can be reasonably manufactured and inventory controlled as a single pipe.

In the connecting pipe set made of the thermoplastic resin of the present invention, as described above, the inner diameter d ₁ of the connected pipe B is set to be equal to or smaller than the outer diameter D _{1 of the} outlet 10 of the connecting pipe A. However, it can connect easily using the connection method of this invention mentioned above. That is, the outer peripheral surface of the receiving port 20 of the connected pipe B is softened by preheating with a preheating heater 60 (see FIG. 7), or the diameter thereof is expanded by softening, and the connecting pipe A is connected to the receiving port 20 of the connected pipe B. The insertion slot 10 can be inserted and connected.

  As shown in FIGS. 7 and 8, the preheater 60 is provided, for example, in a belt-like rubber sheet 61 having a length substantially the same as the circumference of the outer peripheral surface of the receiving port 20 of the connected pipe B, and the rubber sheet 61. In addition, the heating wire 62 extending in a meandering manner with respect to the longitudinal direction of the sheet and a thermocouple (not shown) are provided, and the voltage is controlled by a dedicated voltage application device so as to reach the set temperature. FIG. 7 is a cross-sectional view showing the meandering state of the heating wire 62.

Examples of the material of the rubber sheet 61 include Teflon (registered trademark) and the like, and a thickness of 1 to 3 mm is appropriate. The other end of the rubber sheet 61 is provided with a pair of holes 61a through which the pair of energization terminals 62a of the preheater heater 60 wound around the receiving port 20 of the connected pipe B are inserted, and a stopper (not shown) that secures both ends. A landing part is provided. For the fastening portion, a mechanism that connects both ends of the rubber sheet 61 using, for example, a highly stretchable rubber belt or a hook can be adopted so that the diameter of the receiving port 20 of the connected pipe B can be accommodated.
In FIG. 7, the preheating heater 60 is illustrated as a case where the meandering of the heating wire 62 is folded at one end of the rubber sheet 61, but is folded like the heating wire 42 of the fusion heater 40 shown in FIG. 4. It is also possible to arrange energization terminals at both ends of the rubber sheet.

As described above, the outer peripheral surface of the receiving port 20 of the connected pipe B is softened by preheating with the preheating heater 60 or is expanded by softening, and the connecting port A is inserted into the receiving port 20 of the connected pipe B. The connecting method for inserting and connecting 10 is, in particular, the inner diameter d _{1 of the} pipe B to be connected is 200 mm or more, specifically 200 to 3000 mm, preferably 300 to 1500 mm, and d ₁ ≦ D ₁ (connecting pipe It is suitable for the connection of a large-diameter pipe having an outer diameter of A). In this case, it is preferable that the configuration and connection method of the connecting pipe A and the connected pipe B are as follows (see FIGS. 1 and 8). ).

(1) The difference (d ₁ −D ₁ ) between the inner diameter d _{1 of the} receiving port 20 of the connected pipe B and the outer diameter D ₁ of the insertion port 10 of the connecting pipe A is preferably −10 to 0 mm, and −5 More preferably, ˜0 mm. When the difference is larger than −10 mm, it is difficult to sufficiently expand the diameter of the receiving port 20 to such an extent that the insertion port 10 of the connecting tube A can be easily inserted into the receiving port 20 of the connected tube B.
(2) It is preferable that the wall thickness T of the receiving port 20 of the connected pipe B is 20 to 40 mm. If the wall thickness T exceeds 40 mm, the wall thickness of the receiving port 20 becomes too thick and it is difficult to sufficiently expand the diameter. If the thickness T is thinner than 20 mm, the strength of the connecting portion where the receiving port 20 and the insertion port 10 are connected is insufficient. To do. In this case, the thickness of the insertion opening 10 (tip portion) of the connecting pipe A is not particularly limited, but for example, 30 to 60 mm is appropriate.
(3) As described above, the connecting pipe A has the first tapered surface portion 12 formed on the outer peripheral surface of the tip of the insertion port 10, and the connected pipe B has the first reverse taper on the inner peripheral surface of the opening end of the receiving port 20. The surface portion 22 is preferably formed. In particular, it is preferable when the inner diameter d ₂ of the receiving port 20 of the connected pipe B in the expanded state is smaller than the outer diameter D ₁ of the insertion port 10 of the connecting pipe A.

(4) The ratio (diameter expansion ratio) d ₂ / d ₁ between the inner diameter d ₁ of the receiving port 20 of the connected pipe B before preheating and the inner diameter d ₂ of the receiving port 20 of the connected pipe B expanded by preheating is It is preferable that it is 1-1.01, and 1-1.005 is more preferable.
If the ratio d ₂ / d ₁ is larger than 1.01, the insertion port 10 of the connection pipe A can be easily inserted into the reception port 20 of the connected pipe B, but between the reception port 20 and the insertion port 10. An excessive gap is easily formed, and it becomes difficult to prevent fluid such as water from leaking and to secure liquid tightness. If the diameter is smaller than 1, the diameter expansion rate is too small, so that the taper surface portion 13 and the reverse tapered surface portion 22 are not easily inserted when the tip of the insertion port 10 and the receiving port 20 is not provided.

(5) The outer peripheral surface of the receiving port 20 of the connected pipe B is preferably preheated at 80 to 120 ° C, more preferably 100 to 120 ° C. If the temperature is higher than 120 ° C., the outer peripheral surface of the receiving port 20 of the connected pipe B may be melted, resulting in a decrease in strength. If the temperature is lower than 80 ° C., the receiving port 20 is not sufficiently softened and the insertion port 10 of the connecting tube A is obtained. Cannot be inserted easily.

By satisfying the above conditions (1) to (5), it is possible to easily connect even a large-diameter pipe connection work. Further, as described above, the fusion heater is connected to the insertion port and the reception port. It is possible to form an EF pipe connection structure that can reliably stop water by being interposed between the two.
Hereinafter, a method for connecting a thermoplastic resin pipe of the present invention using the above-described connecting pipe will be described with reference to the drawings.

  First, as shown in FIG. 8, a fusion pipe 40 is prepared with a connected pipe B wound around the inner peripheral surface of the receiving port 20, and the fastening ring 30 is loosened in the concave circumferential groove 24 of the receiving port 20. The preheating heater 60 is wound around the outer peripheral surface of the receptacle 20. At this time, the thermocouple of the preheating heater 60 is brought into contact with the inner peripheral surface of the receiving port 20, preferably the position of the receiving end 22.

  Here, the fastening ring 30 will be described with reference to FIGS. The fastening ring 30 includes a steel strip-shaped member 31 that is longer than the circumferential length of the concave circumferential groove 24 of the receiving port 20 of the connected pipe B, and a strip-shaped member 31 that has one end extended outward and the other end bent inward to form a ring shape. And a tightening mechanism 33 attached to the outer end of the ring-shaped band member 31. The tightening mechanism portion 33 includes a screw shaft 33a fixed to the outer end of the belt-like member 31, a stopper block 33b having a hole through which the screw shaft 33a is inserted, and a screw-like screw shaft 33a that is screwed into and out of the belt-like member. And a fastening handle 33c for adjusting the diameter of the 31 wheels. By operating the tightening handle 33c of the tightening ring 30, the receiving port 20 of the connected pipe B can be tightened.

Next, the preheating heater 60 is energized to preheat the outer peripheral surface of the receiving port 20 of the connected pipe B until the temperature reaches 80 to 120 ° C. At this time, it is preferable to confirm that the temperature is 23 ± 2 ° C. at the portion of the receiving port 22 on the inner peripheral surface of the receiving port 20 even when the outside air temperature at the construction site is low. Since the temperature of the outer peripheral surface is higher than the temperature of the inner peripheral surface, the pre-heated receiving port 20 of the connected pipe B is softened and a force acts in the direction of expanding the diameter by decreasing the elastic modulus. More specifically, a thermoplastic resin pipe having a large diameter of, for example, 200 mm or more is formed by spirally winding a molten thermoplastic resin from an extruder while being wound around a lead pipe, and is manufactured. Since compressive stress is always applied to the inner peripheral surface side, when the outer peripheral surface side is preheated and softened as described above, a part of the compressive stress on the inner peripheral surface side is released and a force acts in the direction of expanding the diameter. The diameter of the receiving port is increased by As a result, as shown in FIG. 8, the diameter of the receiving port 20 is increased in a reverse taper shape in which the opening end side of the inner peripheral surface is slightly wider than the inner portion. At this time, the inner diameter d ₂ of the diameter-enlarged receiving port 20 of the connected pipe B is about 1 to 1.01 times the inner diameter d ₁ (see FIG. 1) before the diameter is increased. Note that the preheater 60 is such that the heating wire 62 is provided in a meandering manner on the rubber sheet 61, the rubber sheet 61 has elasticity, and the fastening portion of the rubber sheet 61 wound around the receiving port 20 is long. By being adjustable, etc., the diameter of the receiving port 20 of the tube B to be connected is extended following the expansion, and the diameter of the receiving port 20 is not hindered.

  On the other hand, the connecting pipe A is fitted with a support ring 70 shown in FIGS. 8 and 9 along the inner peripheral surface of the insertion slot 10. The support ring 70 includes a long plate-like member 71 made of stainless steel and bent in an arc shape, and a connecting tool 72 that connects a pair of opposing free ends 71a. The connecting tool 72 further includes a screw shaft 73. , 74 and an adjustment unit 75. The support ring 70 can adjust the outer diameter of the entire plate member 71 by rotating the adjusting portion 75 coaxially with the screw shafts 73 and 74.

  Next, the connecting pipe A and the connected pipe B are connected. At this time, as shown in FIG. 10, the wire ropes 81 and 82 are wound around the trunk portions 11 and 21 of the connecting pipe A and the connected pipe B. The hooks 83 and 84 and the chains 85 and 86 are attached to both the wire ropes 81 and 82, and both the chains 85 and 86 are connected by the lever block 87. Then, by operating the lever block 87, the connecting pipe A and the connected pipe B are forcibly pulled in the axial direction, and the insertion port 10 is inserted into the receiving port 20 whose diameter is increased.

FIG. 11 shows a state where the insertion port 10 of the connecting pipe A is inserted into the receiving port 20 of the connected pipe B. In this state, the axial positions of the support ring 70 and the tightening ring 30 are substantially the same. After the insertion port 10 is inserted into the receiving port 20 in this way, the preheating heater is removed from the connected tube B and the fastening ring 30 is tightened, so that the insertion port 10 and the receiving port 20 have a radially inner side and an outer side as indicated by arrows. Pressure is applied to the inner peripheral surface of the receiving port 20 of the connected pipe B, thereby bringing the tapered surface portion 12 of the insertion port 10 of the connecting pipe A into surface contact. Then, in this state of contact with the surface, the heating wire of the fusion heater 40 is energized with a voltage (about 13 V to 50 V), and the thermoplastic resin sheet of the fusion heater 40 and the outer peripheral surface of the connection pipe A in the vicinity thereof and the covered surface. The inner peripheral surface of the connecting pipe B is melted, and then the energization is stopped, whereby the melting portion is cooled and the connecting pipe A and the connected pipe B are fusion-connected integrally.
Thereafter, the support ring 70 is removed from the open end of the connection pipe A, and the fastening ring 30 is removed.

In such a connection method of the present invention, the outer peripheral surface of the inlet 10 is obtained by contacting and supporting the inner peripheral surface of the connection pipe A by the support ring 70 and tightening the outer peripheral surface of the connection pipe B by the tightening ring 30. The surface contact in the pressing state of the inner peripheral surface of the receiving port 10 can be sufficiently ensured, and the fused portion can be uniformly formed without unevenness. In addition, the diameter of the receiving port 20 of the connected pipe B is increased by preheating, and the inner peripheral surface becomes a reverse taper shape, and a tapered surface portion 12 is formed on the outer peripheral surface of the insertion port 10 of the connecting tube A so as to correspond to the reverse tapered surface portion. As a result, the pressure difference in the axial direction hardly occurs in the fusion heater 40 between them, and the fusion part can be uniformly formed evenly in the axial direction.
Further, the connecting structure of the connecting pipe A and the connected pipe B is such that after the insertion port 10 and the receiving port 20 are fused and integrated, the receiving port 20 warmed by preheating shrinks the thermoplastic resin due to natural cooling. Since the force acts in the direction of the movement, the state where the insertion port 20 is tightened by the receiving port 20 is maintained, and a high fusion strength is obtained. Therefore, the connection structure between the connecting pipe A and the connected pipe B is obtained in which the distortion of the insertion opening 10 and the receiving opening 20 is different, that is, the distortion of the receiving opening 20 is larger than the distortion of the insertion opening 10.

(Embodiment 2)
FIG. 12 shows a perspective view in which a part of the fusion heater 140 in Embodiment 2 of the present invention is omitted. The connecting pipe set of the second embodiment includes this fusion heater 140. FIG. 13 shows a state in which the connecting pipe A and the connected pipe B are connected using the fusion heater 140.
The fusion heater 140 includes a thermoplastic resin sheet 141 and a heating wire 142 and has a configuration substantially the same as that of the fusion heater described in the first embodiment, but is shorter than the belt-like thermoplastic resin sheet 141. The cross-sectional shape cut into a wedge shape is a wedge shape, and is different in that it has a plurality of hooks 143 on the end surface on the thin side of a pair of end surfaces extending in the longitudinal direction.

  Each dimension of the thermoplastic resin sheet 141 depends on the size of the connecting pipe A and the connected pipe B, but the length L in the longitudinal direction is substantially equal to the peripheral length of the inner peripheral surface of the receiving port 20 of the connected pipe B. The length W is about 60 to 150 mm (preferably about 70 mm), the thickness t1 on the thick side is about 3 to 10 mm (preferably about 4 mm), and the thickness t2 on the thin side is 2 to 4 mm. About (preferably about 2 mm). Further, in this sheet 141, the inner surface 141b in contact with the tapered surface portion of the connecting tube A is inclined at an inclination angle θ2 with respect to the outer surface 141a in contact with the reverse tapered surface portion or parallel surface portion of the connected tube B. The inclination angle θ2 can be obtained from each dimension of the sheet 141. When the inner peripheral surface of the receiving pipe B is a parallel surface, the taper surface 12 of the connecting pipe A (see FIG. 1) is tapered. What is necessary is just to set to the same angle as angle (theta) (for example, 1-3 degrees), and when the inner peripheral surface of the receiving port of the to-be-connected pipe B is a reverse taper surface (for example, 1-3 degrees), the inclination angle of this reverse taper surface And the taper angle θ of the connecting pipe A.

For example, the hook 143 is integrally formed of the same thermoplastic resin as the sheet 141 or is formed by embedding a base end of a metal hook in the sheet 141. When the sheet 141 is wound in a cylindrical shape, the plurality of hooks 143 are arranged at equal intervals.
The heating wire 142 is arranged in a meandering manner in the longitudinal direction of the sheet 141, and both ends are led out from the end face on the thin side of the sheet 141.

  When connecting the connecting pipe A and the connected pipe B, first, the fusion heater 140 is wound around the inner peripheral surface of the receiving pipe 20 of the connecting pipe B, and both ends of the heating wire 142 are received from the openings of the receiving opening 20. Go out. Thereafter, in the same manner as in the first embodiment described with reference to FIG. 8, the fastening ring is fitted into the concave groove of the receiving port in a loosened state, and a preheating heater is wound around the outer peripheral surface of the receiving port until the temperature reaches 80 to 120 ° C. Preheat. On the other hand, the connecting pipe A is provided with a support ring (not shown) along the inner peripheral surface of the insertion slot 10.

Next, the connecting pipe A and the connected pipe B are connected. At that time, similarly to the first embodiment described in FIG. 10, a wire rope is wound around the trunk of the connecting pipe A and the connected pipe B, Attach hooks and chains to both wire ropes and connect both chains with lever blocks. Then, by operating the lever block, the connecting pipe A and the connected pipe B are forcibly pulled in the axial direction, and the insertion port 10 is inserted into the receiving port 20 whose diameter has been increased (see FIG. 13A).
At this time, particularly in the case of a large-diameter pipe, the inner diameter of the receiving port 20 is made larger than the outer diameter of the insertion port 10 in order to facilitate the connection. A gap is likely to exist between the outer peripheral surfaces of the mouth. Therefore, as shown in FIG. 13B, the wedge-shaped fusion heater 140 is drawn toward the opening end side of the receiving port 20 of the connected pipe B, and the outer surface (outer peripheral surface) 141a and the inner surface (inner periphery) of the fusion heater 140 are drawn. Surface) 141b is brought into close contact with the outer peripheral surface of the receiving port 20 and the outer peripheral surface of the insertion port 10 to eliminate a gap between the connecting pipe A and the connected pipe B. At this time, the fusion heater 140 can be pulled by hanging ropes on the plurality of hooks 143.
Thereafter, the connecting wire A and the connected tube B are fused and connected together without any gap by energizing the heating wire 12.

  The use of the present invention is not particularly limited, but can be applied to, for example, a thermoplastic resin pipe for water and sewage and a connection method thereof, and particularly, a thermoplastic resin pipe having a large diameter of 200 to 3000 mm and a connection method thereof. It is suitable for.

It is the 1st side sectional view explaining one embodiment of the pipe set for connection made of the thermoplastic resin of Embodiment 1 concerning the present invention, and those connection methods. FIG. 6 is a side cross-sectional view illustrating a modification of the body portion of the connection pipe according to the first embodiment. FIG. 3 is a plan view showing a tightening ring in the first embodiment. It is a top view which shows the fusion | melting heater in Embodiment 1. FIG. It is the elements on larger scale explaining the shape dimension of the heating wire of the fusion heater in Embodiment 1. FIG. FIG. 6 is a side sectional view showing a modification of the connection pipe of the first embodiment. It is a plane sectional view showing the preheating heater in Embodiment 1. It is the 2nd sectional side view which shows the state which expanded the receiving port of the to-be-connected pipe shown in FIG. 1, and demonstrates the continuation of the connection method. FIG. 2 is a configuration explanatory diagram including a partially enlarged view of a support ring in the first embodiment. It is a perspective view of the principal part which shows the state which inserts the insertion port of the connection pipe in Embodiment 1 in the receiving port which expanded the diameter of the to-be-connected pipe. FIG. 6 is a third side cross-sectional view illustrating a state in which the connection port in Embodiment 1 is fused after being inserted into the diameter-enlarged receiving port of the connected tube and illustrating the continuation of the connection method. The perspective view which abbreviate | omits a part of fusion heater in Embodiment 2 of this invention is shown. It is a figure which shows the state which connects the connecting pipe and to-be-connected pipe in Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 28 Insert 11 Body 12 First taper part 13 Second taper part 14 Corrugated outer pipe part 18, 20 Receptacle 21 Body 22 First reverse taper part 23 Second reverse taper part 24 Concave groove 30 Clamping ring 40, 140 Fusion heater 41, 141 Thermoplastic resin sheet 42, 142 Heating wire 60 Preheating heater 61 Rubber sheet 62 Heating wire 70 Support ring 143 Hook A Thermoplastic resin connecting tube (connecting tube)
B Connected pipe made of thermoplastic resin (connecting pipe)
D ₁ inner diameter D ₂ inner diameter (after expansion)
d ₁ outer diameter L length T thickness t1, t2 thickness W width

Claims (16)

  When connecting a connecting pipe made of thermoplastic resin having an insertion opening at least at one end and a connecting pipe made of thermoplastic resin having a receiving opening at least at one end, the outer peripheral surface of the receiving opening of the connecting pipe is preheated by a preheating heater. A method for connecting a thermoplastic resin pipe, characterized in that the connection is made by softening or softening / expanding the diameter of the pipe and inserting the connection pipe into the connection port. When the inner diameter of the receiving port of the connected pipe before preheating is d ₁ and the inner diameter of the receiving port of the connected pipe softened and expanded by preheating is d ₂ , the equation (1)
d ₂ / d ₁ (1)
The thermoplastic resin pipe connection method according to claim 1, wherein the ratio represented by the formula is 1 to 1.01.   The method for connecting a thermoplastic resin pipe according to claim 1 or 2, wherein the outer peripheral surface of the receiving port of the connected pipe is preheated at 80 to 120 ° C. Before inserting the connection pipe outlet into the connection pipe receptacle, wrap a heating wire near the outer circumference of the connection pipe insertion or the inner circumference of the connection pipe receptacle,
The insertion tube of the connecting pipe is inserted into the receiving port of the connected pipe, and then the connecting pipe and the connected pipe are integrally fusion-connected by energizing the heating wire. Connection method for thermoplastic resin pipes.   Before inserting the connection tube insertion port into the connection tube receiving port, a fusion heater having a belt-like thermoplastic resin sheet and a heating wire provided on the surface or inside of the sheet is inserted into the connection tube. Wound on the outer peripheral surface of the port or the inner peripheral surface of the receiving port of the connected tube, and after inserting the connecting port into the receiving port of the connected tube, by energizing the heating wire, the connecting tube and the connected tube The method for connecting thermoplastic resin pipes according to any one of claims 1 to 3, wherein the two are integrally fused and connected.   The fusion heater has a wedge-shaped cross-section cut in the short-side direction, and after inserting the connection pipe inlet into the connection pipe receptacle, the fusion heater is moved to the opening end side of the connection pipe receptacle. The thermoplastic resin pipe according to claim 5, wherein the gap between the connecting pipe and the connected pipe is removed by drawing, and then the connecting pipe and the connected pipe are fusion-bonded integrally by energizing the heating wire. Connection method.   It is a pipe set for connection used for the connection method of the thermoplastic resin pipes as described in any one of the above-mentioned Claims 1-6, Comprising: This connection pipe made from a thermoplastic resin which has an opening in at least one end, and this A connecting pipe made of a thermoplastic resin having at least one receiving port into which the insertion port of the connecting pipe is inserted, and the inner diameter of the receiving port of the connecting pipe is equal to or more than the outer diameter of the insertion port of the connecting pipe Connection pipe set characterized by being set small.   The connecting pipe set according to claim 7, wherein an inner diameter of the receiving port of the connected pipe is 200 to 3000 mm.   The connecting pipe set according to claim 8, wherein the difference between the inner diameter of the receiving port of the connected pipe and the outer diameter of the connecting port is -10 to 0 mm.   The connection pipe set according to claim 8 or 9, wherein a thickness of a receiving port of the connected pipe is 20 to 40 mm.   The connecting pipe is formed with a tapered surface portion on the outer peripheral surface at the tip end thereof, and the connected pipe is formed with an inverted tapered surface portion or a parallel surface portion on the inner peripheral surface of the opening end at the receiving port. Tube set for connection described in 1.   A belt-like thermoplastic resin sheet and a heating wire provided on the surface or inside of the sheet are wound around the outer peripheral surface of the connection pipe outlet or the inner peripheral surface of the connection pipe receptacle, 7. A fusion heater for further fusion-connecting the connection pipe and the connected pipe together by energizing the heating wire after inserting the connection pipe outlet into the connection pipe receptacle. The connection pipe set according to any one of 11.   The connecting pipe set according to claim 12, wherein the fusion heater has a wedge-shaped cross-sectional shape cut in a short direction.   The connecting pipe set according to claim 13, wherein the fusion heater has a plurality of hooks on an end face on a thin side among a pair of end faces extending in a longitudinal direction.   The connecting pipe has a receptacle having the same shape and dimension as the receptacle of the connected pipe at the other end, and the connected pipe has an outlet having the same shape and dimension as the receptacle of the connecting pipe at the other end. The tube set for connection as described in one.   The connection pipe which consists of a thermoplastic resin connection pipe single-piece | unit in the connection pipe set of Claim 15.

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