JPH0346315Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a structure for sealing the tube end of a metal corrugated tube used in a heat pipe or the like.

Prior Art Corrugated corrugated pipes are flexible, so they are used as containers for heat pipes that transport heat over long distances or for snow melting. When configuring a corrugated pipe as a heat pipe, it is necessary to completely seal the end. Conventionally, the end of the corrugated pipe 1 has been drawn into a perfect circle to create a sealed structure, as shown in Fig. 3. Alternatively, it is formed into a cylindrical shape by tube expansion, and a perfect circular cap 3 is fitted inside the cylindrical portion 2, and welded.

Problems to be Solved by the Invention However, the above-mentioned processing into a cylindrical shape is generally performed cold, and residual stress is generated at the end of the tube as a result of the processing. On the other hand, heat pipes are placed in corrosive environments, such as being directly exposed to fluids such as high-temperature gases and refrigerants. By the way, copper alloys or stainless steel are generally used as metal corrugated tubes for heat pipes in terms of thermal conductivity and corrosion resistance. If residual stress is generated in a portion as described above, stress corrosion is likely to occur in that portion in a corrosive environment, resulting in a problem that durability is inevitably inferior. Also, when processing the end of a tube into a cylindrical shape, lubricating oil and coolant are used to reduce friction with the die and plug.
These lubricants and coolants impair the performance of the heat pipe, so they must be completely removed after processing. There was a problem that the work could not be avoided and the number of steps increased.

This invention was made in view of the above-mentioned circumstances, and aims to provide a sealing structure for the end of a corrugated pipe that is excellent in durability and easy to process.

Means for Solving the Problems In order to achieve the above-mentioned purpose, this invention has been developed by cutting a metal corrugated pipe so that the inner or outer circumferential shape of the pipe end is the same as the inner circumferential shape of the pipe end. or the inner periphery shape is the same as the outer periphery shape of the tube end, and a metal sealing member made of cast material or formed material treated to remove residual stress is fitted and welded. It is characterized by this.

Function According to this invention, the end of the corrugated pipe is completely closed by the sealing member, and no residual stress is generated, so that stress corrosion cracking can be prevented.

Embodiments Below, embodiments of this invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of this invention, in which a pipe end 1 is formed by cutting a corrugated pipe 1 made of metal such as copper alloy or stainless steel.
0 is left in its original waveform, and a bottomed cylindrical cap 11 at the tube end 10 is fitted. This cap 11 has a cylindrical portion 11a formed in a corrugated shape to match the outer peripheral shape of the tube end 10, and a bottom portion 11b having a spherical pressure-resistant structure.For example, the cap 11 is shaped by deep drawing. is applied and then subjected to a residual stress removal treatment such as annealing, that is, a formed material is subjected to a residual stress removal treatment. The cap 11 is fitted onto the outer periphery of the tube end 10 and fixed to the corrugated tube 1 by welding.

Therefore, in the above-mentioned sealed structure, there is no residual stress in both the pipe end 10 and the cap 11 of the corrugated pipe 1, and furthermore, no residual stress is generated due to processing during the sealing process, so there is no risk of stress corrosion occurring. Similarly, there is no fear that cracks or cracks will occur in the welded portion, and therefore durability can be made higher than ever before.

FIG. 2 is a schematic sectional view showing another embodiment of this invention, and the example shown here shows a plug 1 which is cast as a sealing member on the inner peripheral side of the tube end 10.
2 is fitted to seal the tube end 10. That is, the plug 12 is manufactured by casting so that its outer circumferential shape matches the inner circumferential shape of the corrugated pipe 1, and cast materials generally have much smaller residual stress than molded materials, and substantially have no residual stress. I can say no. Then, the end of the corrugated pipe 1 is sealed by welding the plug 12 in a state in which the plug 12 is hermetically fitted to the inner peripheral side of the pipe end 10.

Even with this structure, no residual stress is generated in the pipe end 10 or the plug 12 due to machining, so it has excellent durability without the risk of stress corrosion or cracking at the welded part. be able to.

Note that a method such as TIG welding or resistance welding can be used to weld the cap 11 and the plug 12, and a lost wax method, for example, can be used to manufacture the plug.

Effects of the invention As is clear from the above explanation, according to the sealing structure of this invention, the inner circumferential shape or the outer circumferential shape is formed on the inside or outside of the pipe end produced by cutting a metal corrugated pipe. The structure is made by fitting and welding a sealing member that has the same shape as that of a cast material or a molded material that has been treated to eliminate residual stress, that is, a sealing member that has virtually no residual stress, so it is suitable for the pipe ends of corrugated pipes and for sealing. It is possible to obtain a highly durable sealed structure in which no residual stress is generated in the member and, therefore, there is no risk of stress corrosion, cracking of welded parts, or cracks. In addition, with this invention, there is no need to perform any special processing on the corrugated pipe itself, so the sealing work can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing one embodiment of this invention, Fig. 2 is a schematic sectional view showing another embodiment of this invention, and Fig. 3 is a schematic sectional view showing a conventional structure. It is a diagram. 1...corrugated pipe, 10...pipe end, 11...
...Cap, 12...Plug.

Claims (1)

[Scope of utility model registration request] On the inside or outside of the pipe end produced by cutting a metal corrugated pipe, the outer circumferential shape is the same as the inner circumferential shape of the pipe end, or the inner circumferential shape is the same as the outer circumferential shape of the pipe end, and A pipe end sealing structure for a corrugated pipe, characterized in that a metal sealing member made of a cast material or a molded material subjected to residual stress removal treatment is fitted and welded.