JPH0439028A - Press-bonding method of resin pipe and its device - Google Patents

Abstract

PURPOSE:To enable resin pipes to be easily welded to a tubular joint by a method in which between two pipes of thermoplastic resin, the tubular joint of the same kind is concentrically inserted, and in the state where the end surfaces of two resin pipes are press-contacted with both end-surfaces of the joint, the tubular joint is rotated around its axis. CONSTITUTION:A tubular joint 3 is concentrically inserted between two polyethylene pipes so that inclined end surfaces 1a, 2a, 3a are respectively surface- contacted mutually, and the axial forces shown by the arrows f1, f2 are applied to said polyethylene pipes 1, 2, whereby the inclined surfaces 1a, 3a, and 2a, 3a which are surface-contacted are press-contacted. In this state, when the tubular joint 3 is rotated at high-speed in the direction of arrow R around its central axis S, friction heat is generated over all periphery, whereby the end parts in the axial direction of the polyethylene pipes 1, 2 and the tubular joint 3 are quickly melted under heating and are integrally welded. Then, the welded parts are naturally cooled and the bonding of the pipes is finished.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a pressure welding method for thermoplastic resin pipes, particularly polyethylene pipes and bolybdenum pipes, for fusion-bonding them together via a similar type of joint, and a method for joining the same. It is related to the device.

(Prior Art) Regarding the joining method of thermoplastic resin pipes, the conventional method is to heat the inner circumferential surface of the joint and the outer circumferential surface of the resin pipe to near the melting point of the resin, and then press-fit them both inside and outside. Using the heat fuse method, electricity is passed through a heating wire buried inside the joint to generate heat, and the inner circumferential side of the joint and the outer circumferential side of the resin pipe fitted inside the joint are melted and joined. The so-called electrofusion method is well known.

(Problems to be Solved by the Invention) Among the conventional methods described above, in the case of the heat fuse method, the inner circumferential surface of the joint and the outer circumferential surface of the resin pipe are affected by the outside temperature when the temperature is raised to near the melting point. , It takes time to raise the temperature to a predetermined temperature, which is inefficient, and furthermore, after the temperature has been raised, it is necessary to hold at least one of the joint and the resin pipe, which are considerably heated, and press-fit them immediately. Joining work requires skill. Furthermore, if this heat fusion method were to automate the bonding, it would require a large-scale and very expensive apparatus.

In addition, although the electrofusion method is superior to the heat fusion method described above in that it is possible to simultaneously melt the joint and the resin pipe, the heating wire buried inside the joint moves as the heat is melted. There was a possibility that short circuits would occur, which would result in partially unfused spots, making the intended bonding unreliable. Moreover, if the resin pipe or joint is even slightly distorted into a flat shape and a gap is created between the two peripheral surfaces, the fusion will be incomplete and it will be difficult to achieve a specified strength of the joint.Furthermore, in the case of this electrofusion method, However, it is difficult to control and manage the heating time, and it is necessary to modify the heating time for each site.

There was a drawback that the joining work was troublesome.

This invention was made in view of the above-mentioned circumstances, and provides a resin pipe that can melt the joint portion of a resin pipe and a joint very quickly and uniformly over the entire area, thereby making it possible to reliably and easily perform a specified joint. It is an object of the present invention to provide a pressure welding method and a pressure welding apparatus for resin pipes that can effectively realize such pressure welding.

(Means for Solving the Problems) In order to achieve the above object, the method for pressure welding resin pipes according to the present invention provides a method for joining two thermoplastic resin pipes by connecting tubular joints of the same type as these resin pipes concentrically. With the end faces of the two resin pipes in pressure contact with both end faces of the tubular joint in the axial direction, the tubular joint is rotated around its axis to generate frictional heat and connect the resin pipes. This is to fuse together the tubular joint.

Further, the pressure welding device for resin pipes according to the invention described in claim 2 is a pair of pipes capable of fixing and holding two thermoplastic resin pipes concentrically with each other with their end surfaces facing each other. a fixture; a joint holder that holds a tubular joint of the same type as the resin pipe rotatably around its axis, and interposes the tubular joint concentrically between opposing end surfaces of the two resin pipes; It is equipped with a drive mechanism that drives and rotates the tubular joint around its axis, and a pulling mechanism that pulls the two resin pipes and the tubular joint together in the axial direction so that their end surfaces are pressed against each other. It is something.

(Function) According to the pressure welding method for resin pipes according to the present invention, by rotating the tubular joint interposed concentrically between two resin pipes around its axis, the axial direction of the tubular joint can be adjusted. Frictional heat is generated evenly and uniformly over the entire circumference of the contact surface between both end surfaces and the end surfaces of the two resin tubes that are press-welded to these both end surfaces, and both end surfaces are rapidly melted. They are fused and fixed together by receiving the pressure welding force. This allows unskilled people to join the specified joints without being affected by the outside temperature and without having to move either side after heating, just rotating the joints in a press-welded state. Even if there is a bond, it can be done easily and quickly, and by fusion bonding around the entire circumference, a reliable and high-strength bond can be obtained.

Further, according to the pressure welding device for resin pipes according to the invention described in claim 2, the pair of pipe fixtures and the joint holder each hold two resin pipes and a tubular joint, so that the above-mentioned By performing the joining work, it is ensured that the resin pipe and the tubular joint are held concentrically, and it is also possible to apply pressure evenly to the entire circumference of the end face, making it possible to stably perform reliable and high-strength joining. I can do it.

(Example) Hereinafter, an example of the joining method of the present invention will be described based on the drawings.

FIG. 1 shows a method of concentric pressure welding of two straight polyethylene pipes 1.2 through a tubular joint 3 made of the same type as these, that is, made of polyethylene. are formed with outwardly inclined surfaces 1a and 2a of approximately 45 degrees, respectively, while the tubular joint 3
The inner diameter DI is the inner diameter d of both polyethylene pipes 1.2.
i, and the outer diameter D2 is set slightly larger than the outer diameter d2 of both the polyethylene pipes l and 2, and both end faces in the axial direction are inwardly inclined surfaces 3a, 3a of about 45 degrees, respectively. is formed.

The tubular joint 3 is interposed concentrically between the two polyethylene pipes 1 and 2 such that the inclined end surfaces 1a and 2a and 3a and 3a are in surface contact with each other, and the two polyethylene pipes 1. 2, arrow f1. f2
By applying an axial force shown by
3a and 2a, 3a are pressed together.

In this state, by rotating the tubular joint 3 around its axis S at high speed in the direction of arrow R, frictional heat is generated over the entire circumference of the contact inclined end surfaces 1a, 3a and 2a, 3a. Due to frictional heat, the inclined end surface 1a,
The axial end portions of the polyethylene pipe 1.2 and the tubular fitting 3 including 3a and 2a, 3a are rapidly heated and melted,
They are fused and fixed together by the above-mentioned pressure welding force. Thereafter, the rotation of the joint 3 is stopped and the fused portion is allowed to cool naturally, thereby completing the prescribed pipe joining.

The quality of the fusion bond can be sufficiently determined by visually checking whether or not beads formed by melted residue are connected in a linear manner on the circumferential surface of both ends of the joint 3 in the axial direction after joining. It is.

FIG. 2 shows a method of joining two polyethylene pipes 1, 2 at right angles through a bent pipe 4 such as an elbow or a cheese.

4a and the inwardly inclined surfaces 1a, 2 of each polyethylene pipe 1.2
Tubular joints 3, 3 are interposed between them, respectively, and as in the case of FIG.
Furthermore, frictional heat is generated around the entire circumferences of 2a, 3JL, 3a, and 4a, and the polyethylene pipe 1 and the bent pipe 4 and the polyethylene pipe 2 and the bent pipe 4 are joined.

The shapes of the contact end surfaces 1a, 2a, 3a between the polyethylene pipe 1.2 and the fitting 3 and the shapes of the contact end surfaces 4a, 3a between the bent pipe 4 and the fitting 3 are as shown in FIGS. 1 and 2 above. In addition to the shapes shown, various shapes such as those shown in FIGS. 3(A) to (G) are possible. Among these, as shown in FIGS. 1, 2, and 3 (A), (B), and (D), if a contact surface is used that is inclined with respect to the axis S, the joint can be With the rotation of 3, the polyethylene pipe l
, 2, the bent pipe 4, and/or the joint 3 are deformed into a flat shape, the function of straightening them into a perfect circle can be exerted, thereby preventing the occurrence of joint defects due to partial heating. There is an advantage that, as shown in Fig. 3 (E),
As shown in (F) and (G), a configuration in which a cylindrical portion 3A is formed on the joint 3 side that also contacts the outer peripheral surface of the end portion of the polyethylene pipe 1.2 and the bent pipe 4 to expand the contact area. Adopting this has the advantage that the heating and melting time can be shortened and the bonding strength can be increased by that area.

Next, a welding apparatus for implementing the above-described pressure welding method for resin pipes will be described with reference to FIGS. 4 and 5.

In FIGS. 4 and 5, 5 and 6 are a pair of tube fixing devices.

As shown in FIG. 6, a tightening bolt/nut is inserted between the end portions 8a and 8B of a pair of half-arc-shaped tightening pieces 8A and 8B that are pivotally movable around the support shaft 7. A pair of fastening pieces 8A, 8B are fitted onto the polyethylene pipes 1 and 2 to be joined, respectively, and free ends 8a, 8b of these fastening pieces 8A, 8B are attached. By tightening the two polyethylene pipes 1 and 2 through the port nuts 9 so as to bring them closer together, the two polyethylene pipes 1 and 2 are placed in a state where their inclined end faces 1a and 2a face each other with a predetermined distance apart and are concentric with each other. Hold fixed.

lO is a joint holder, and this joint holder lO is the fifth
As shown in the figure, a case 1 has a cover 11 that can be opened and closed by swinging.
2, two small diameter support rollers 1 are spaced apart in the circumferential direction.
3.13 and one large-diameter support roller dual-purpose gear 14, respectively, are rotatably supported, and these support rollers 13.
The tubular joint 3.3 is held rotatably around its axis by the three-point contact between the pipe fittings 13 and the gear 14, and the tubular joint 3 is fixedly held by the pair of pipe fixtures 5 and 6. Opposing inclined end surfaces 1a, 2 of polyethylene pipes 1 and 2
It is configured so that it is interposed concentrically between a.

15 is a motor, which is attached to the outer surface of the case 12;
The gear 14 is fixed to the rotating shaft 15a, thereby forming a rotational drive mechanism. On the other hand, the outer peripheral surface of the tubular joint 3 has a gear-shaped tooth portion 3A that meshes with the gear 14.
is formed, and when the motor 15 operates, the gear 14
The tubular joint 3 is configured to be driven and rotated around its axis via the gear-like teeth 3A.

16 and 17 are installed between both sides of the case 12 and the pair of pipe fixtures 5 and 6, and connect the two polyethylene pipes l, 2 and the tubular joint 3 to their inclined end faces 1a, 3a and 6. This is a hydraulic pulling mechanism that pulls 2a and 3a together in the axial direction so that they are pressed against each other. Three pieces are placed in each area. As shown in FIG. 7, each of the hydraulic pulling mechanisms 16 and 17 includes a hydraulic cylinder 18,
A rod 19A whose one end is connected to the piston 18A and the cylinder lychee 18B of the hydraulic cylinder 18, and whose other end is connected to the pipe fixture 5.6 and the case 12;
It consists of 19B.

According to the pressure welding apparatus for resin pipes having the above configuration, the pair of pipe fixtures 5 and 6 fix and hold the polyethylene pipes 1 and 2, respectively, and the joint holder 10 rotatably holds the tubular joint 3. Accordingly, a tubular joint 3 is connected between two polyethylene pipes 1.2 with their inclined end surfaces 1a
, 3a and 2a, 3a are set concentrically so that they are in slight surface contact with each other.

After such setting, first, the hydraulic cylinders 18 in the hydraulic pulling mechanisms 16 and 17 are contracted to connect the polyethylene pipe l and the joint 3 via the rods 19A and 19B.
By drawing the polyethylene pipe 2 and the joint 3 toward each other in the axial direction, the above-mentioned inclined end surface 1a that makes surface contact,
3a and 2a, 3a are brought into pressure contact with each other.

Next, while maintaining the above pressure contact state, the motor 15 is operated to rotate the tubular joint 3 at high speed around its axis S via the gear 14 and the gear toothed portion 3A.
Frictional heat is generated over the entire circumference of the inclined end surfaces 1a, 3a and 2a, 3a. Due to this frictional heat, the end portion of the polyethylene pipe 1.2 and both end portions of the tubular joint 3 in the axial direction are rapidly heated and heated, as shown by curve X in the graph of FIG.

Then, when the melting point (105 to 130°C) P of the polyethylene pipe 1.2 and the tubular joint 3 is reached, the operation of the motor 15 is stopped, and then the hydraulic cylinder 18 in the hydraulic pulling mechanisms 16 and 17 is activated. By further shrinking, the polyethylene pipe 1 and the joint 3 and the polyethylene pipe 2 and the joint 3 are fused and fixed together.

In the above embodiments, the case where polyethylene pipes are used as the pipes to be joined has been described, but it is also fully possible to apply the present invention to thermoplastic resin pipes such as bolybdenum, polypropylene, and polyacetal.

In addition, in the joining apparatus shown in FIGS. 4 and 5, the gear 1
4 was formed on the outer peripheral surface of the tubular joint 3 to ensure high-speed rotation of the joint 3 without slipping, but no processing was performed on the outer peripheral surface of the tubular joint 3. , the tubular joint 3 via a friction rotating body linked to the motor 15.
It may be configured to rotate at high speed.

(Effects of the Invention) As described above, according to the pressure welding method for resin pipes according to the present invention, it is possible to rotate the tubular joint interposed concentrically between two thermoplastic resin pipes around its axis. By generating uniform frictional heat over the entire circumference of the end surfaces that are in contact with each other, it is possible to fuse them together by applying pressure to them, compared to the conventional method of heating them separately and press-fitting them together. Compared to the fusion method, it is not affected by outside temperature and can melt quickly to improve bonding efficiency, and does not require skill for each task, making it easy for even unskilled workers to perform bonding. . Moreover, since the entire circumference of the contact surface can be uniformly melted, the desired joint can be made reliably and with high strength.

Furthermore, according to the bonding device according to the invention set forth in claim 2,
The concentricity of the resin pipe and the fitting is ensured, and the pressure welding force can be applied evenly to the entire circumference of the end face, making it possible to stably perform the above-mentioned reliable and high-strength joining, and prevent joining errors.
It is possible to prevent the occurrence of bonding defects.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing one embodiment of the joining method of the present invention, FIG. 2 is a longitudinal side view showing another embodiment of the joining method,
3(A) to 3(G) are vertical sectional side views of essential parts showing examples of the shape of the contact end surface, FIG. 4 is a partially broken side view showing the joining device of the present invention, and FIG. 5 is FIG. 84V. Figure 6 is a cross-sectional view taken along line -V, Figure 6 is a cross-sectional view taken along line ■-■ in Figure 4, Figure 7 is an enlarged schematic cross-sectional view of the main parts, and Figure 8 shows the heating rise characteristics of the resin pipe. It is a graph. 1.2...Polyethylene pipe (thermoplastic resin pipe), la
, 2a... End face, 3... Tubular joint, 3a... End face, 5.6... Pipe fixture, lO... Joint holder, 14
...Gear, 15...Motor, 16.17...Hydraulic pulling mechanism.

Claims (2)

[Claims] (1) A state in which a tubular joint of the same type as these resin pipes is interposed concentrically between two thermoplastic resin pipes, and the end faces of the two resin pipes are pressed against both end faces of the tubular joint in the axial direction. A pressure welding method for resin pipes, characterized in that the resin pipe and the tubular joint are fused together by generating frictional heat by rotating the tubular joint around its axis. (2) A pair of pipe fixtures capable of fixing and holding two thermoplastic resin pipes with their end faces facing each other and concentrically with each other, and a tubular joint of the same type as the resin pipes placed around their axes. a joint holder that rotatably holds the tubular joint and interposes the tubular joint concentrically between opposing end surfaces of the two resin pipes;
It includes a drive mechanism that drives and rotates the tubular joint around its axis, and a pulling mechanism that pulls the two resin pipes and the tubular joint together in the axial direction so that their end surfaces are pressed against each other. A pressure welding device for resin pipes, which is characterized by: