JPH03184681A - Joining method for pipings - Google Patents

Abstract

PURPOSE:To arrange many pipings close together in narrow space by inserting the end outer periphery side of one piping into the inner periphery side of the other piping, heating a shape memory alloy ring, bringing both pipings firmly into contact with each other and solidifying these after melting by frictional heat. CONSTITUTION:The end outer periphery side of the one piping 10a is inserted into the end inner periphery side of the other piping 10b. The shape memory alloy ring 13 fitted on the end outer periphery side of the other piping 10b is heated and the inside diameter of this is contracted and an outer periphery part of the one piping 10a is brought firmly into contact with the inner periphery side of the other piping 10b. In that state, both pipings 10a and 10b are rotated relatively or reciprocated in the axial direction. After both pipings are molten by the frictional heat, a molten part is solidified. By this method, a part having deep wall thickness can be welded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for joining two pipes.

(Prior Art) A conventional method for joining pipes in a narrow space will be described with reference to FIG. The figure shows a schematic longitudinal cross-sectional view of a nuclear fusion device in which piping is packed in a narrow space.

Reference numeral 1 in FIG. 3 indicates a vacuum wall forming a vacuum boundary. This vacuum wall 1 is composed of an access port 2 and an access door 3.

A toroidal coil 4 and a poloidal coil 5 are installed outside the vacuum wall 1, and plasma 6 is formed within the vacuum wall 1 by the electromagnetic force of the toroidal coil 4 and poloidal coil 5.

A blanket module 7 consisting of a first wall, a blanket, and a shield is installed between the vacuum wall 1 and the plasma 6. Impurities generated in the plasma 6 by each fusion reaction are evacuated by an impurity removal device 8 via a vacuum exhaust duct 9. The above impurity removal device 8
For example, refers to a diverter or a limiter.

The blanket module 7 has the access door 3
Piping 10 such as a first wall cooling piping, a blanket cooling piping, a shield cooling piping, a tritium cooling piping, and a cooling piping for the impurity removal device 8 are disposed through the tube.

These many pipes 10 are connected to adjacent toroidal coils 4
A large number of them are crowded together in a narrow space between them. Since the piping 10 passes through the access door 3, it is necessary to join the piping 10 on the outside of the access door 3 in order to install the access door 3.

As described above, conventionally, the pipes 10 have to be joined while being closely arranged in a narrow space.

The connection of piping in such a narrow space is currently not very well thought out;
This is done by IG welding.

(Problem to be solved by the invention) However, when using a TIG welding machine,
A space was needed in which the welding machine could go around the circumference of each pipe. Therefore, the overall installation space for the large number of densely arranged pipes 10 becomes larger than necessary, and the space for arranging other electric cables and measuring instruments interferes with this installation space. Sometimes I put it away.

The present invention was made to solve these problems, and it is an object of the present invention to provide a joining method that allows pipes to be easily connected even in a narrow space.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method for joining two pipes, in which the outer circumference of the end of the - side of the pipe is inserted into the inner circumference of the end of the other pipe. A shape memory alloy ring fitted to the outer periphery of the end is heated, and the heating causes the inner diameter of the shape memory alloy ring to contract, so that the outer periphery of the one pipe comes into strong contact with the inner periphery of the other pipe. In this state, the both open tubes are relatively rotated around the axis or reciprocated in the axial direction, and the outer peripheral side and the inner peripheral side are melted by frictional heat, and then the rotation around the axis or the reciprocating movement in the axial direction is stopped and cooled. The molten portion is then solidified.

(Function) The outer periphery of the pipes to be joined does not require a space for the welding machine to go around like in the past, but simply a space for fitting the shape memory alloy ring, that is, a space for the shape memory alloy ring. Only a space corresponding to the thickness needs to exist.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show the state of joining of pipes in each of the fusion devices shown in FIG. 3 as a conventional example.

FIG. 1 is a longitudinal sectional view showing the state before joining.

Of the two pipes, one of the pipes 10a has a smaller outer diameter on the outer peripheral side of the end, forming a step 11. Further, the inner diameter of the end of the other pipe 10b is increased to form a step 12.

A shape memory alloy ring 13 is fitted in advance to the outer periphery of the end of the other pipe 10b. In this state, the outer peripheral end of the one pipe 10a is inserted into the inner peripheral end of the other pipe 10b. By this insertion, the two steps 11 and 12 fit together, and positioning in the axial direction is performed.

Thereafter, the shape memory alloy ring 13 is heated by a heating device (not shown). This heating device may be one that heats with a beater or one that heats with high-temperature fluid. This heating causes the outer diameter of the shape memory alloy ring 13 to contract. Due to this contraction,
The outer periphery of the other pipe lOb is tightened, and the inner periphery side strongly contacts the outer periphery side of the one pipe 10a.

In order to maintain a predetermined contact pressure, a gap is formed between the shape memory alloy ring 13 and the outer circumference of the other pipe 10b, and between the inner circumference of the other pipe 10b and the one pipe 10.
The dimensions of the gap between a and the outer circumferential side are set.

With the contact as described above made, the other pipe 10b is fixed, and the one pipe 10a is rotated about its axis. A rotation drive device (not shown) is used for this rotation. The rotary drive device obtains driving force from a motor or engine, and while the rotary drive device is operating, a heating device that heats the shape memory alloy ring is operated to increase the temperature of the joint. You can also do it.

When such rotation continues, the outer peripheral side of the one pipe 10a and the inner peripheral side of the other pipe 10b are melted by frictional heat. Once the melted portion 14 (FIG. 2) is formed, a large force is applied to the rotational drive device, confirming that melting has occurred. Further, this confirmation may be performed using another temperature sensor or rotational torque detection sensor (not shown).

Thereafter, the molten portion is solidified by stopping the rotation around the axis or by further operating another cooling device (not shown). This completes the bonding.

According to this embodiment, on the outer periphery of the other pipe 10b,
Only a space corresponding to the thickness of the shape memory alloy 13 is required, and there is no need for a space for the welding machine to go around the outer periphery as in the conventional case. Therefore, it becomes possible to arrange a group of pipes consisting of a large number of pipes closely in a narrow space.

In the embodiments described above, the pipes were rotated around the axis to generate frictional heat, but in other embodiments, the pipes could also be reciprocated in the axial direction.

Axial reciprocation is advantageous if the piping is more resistant to compression and tension than torsion. The drive device that performs this axial reciprocating motion can obtain driving force from a motor or an engine.

In addition, in the above embodiment, at the joint of the pipes, the outer diameter of one pipe becomes smaller, forming a step, and the outer diameter of the other pipe becomes larger, forming a step, and both steps fit together. However, in other embodiments, the outer diameter and inner diameter of one pipe may be left as they are, and only the inner diameter of the other pipe may be increased or the outer diameter may be reduced to form a joint. good. At this time, by increasing the inner diameter or decreasing the outer diameter, a step is formed on the other pipe,
This step makes it possible to perform axial positioning. In still other embodiments, the joining portion may be tapered without providing a step. That is, the outer diameter of the outer circumference of the end of one pipe is gradually reduced toward the end to form a tapered surface, and the inner diameter of the inner circumference of the end of the other pipe is gradually increased toward the end to form a tapered surface. do. With both tapered surfaces fitted together, it is possible to rotate around the axis or reciprocate in the axial direction.

[Effects of the Invention] As explained above, according to the present invention, it is sufficient that a space corresponding to the wall thickness of the shape memory alloy ring exists around the outer periphery of the pipes to be joined, and it is possible to arrange a large number of pipes in a narrow space. It becomes possible to arrange the Additionally, compared to conventional welding methods, it is possible to weld parts with deeper wall thicknesses. That is, in conventional welding, the parts of two pipes that can be seen from the outside are joined by welding, but according to the present invention, only the parts where frictional heat is generated are melted and joined. Therefore, welding and joining can be performed only in deep parts that cannot be seen from the outside, that is, deep parts of the thick parts.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a pipe joint before joining, showing an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the pipe joint shown in Fig. 1 after joining, and Fig. 3 shows how pipes are joined in a narrow space. FIG. 2 is a schematic diagram of a vertical cross section (only the right half) of each fusion device shown as a necessary conventional example. DESCRIPTION OF SYMBOLS 1... Vacuum wall, 2... Access port, 3... Access door, 4... Toroidal coil, 5... Toroidal coil, 6... Plasma, 7... Blanket module, 8... ... Impurity removal device, 9... Vacuum exhaust duct, 10a... One pipe, 10b... Other pipe, 13... Shape memory alloy ring, 14...
melted part.

Claims (1)

[Claims] A method for joining two pipes, the outer peripheral end of one pipe is inserted into the inner peripheral end of the other pipe, and a shape memory alloy ring fitted to the outer peripheral end of the other pipe is heated. death,
As the inner diameter of the shape memory alloy ring contracts due to this heating, the outer peripheral side of the one pipe is in strong contact with the inner peripheral side of the other pipe, and the two pipes are rotated relative to each other around the axis or in the axial direction. A method for joining piping, in which the outer peripheral side and the inner peripheral side are melted by frictional heat by reciprocating the piping, and then the rotation around an axis or the reciprocating movement in the axial direction is stopped and the melted portion is solidified by cooling.