JPH01234678A - Multi-layer pipe having gap and manufacture thereof - Google Patents

Abstract

PURPOSE:To maintain a heat insulating function between an inner layer pipe and an outer layer pipe of a multi-layer pipe adapted to be used in a nuclear power plant or the like, and to prevent a relative slip therebetween by disposing a continuous spacer between the inner and outer layer pipes so as to form a gap therebetween, and then by fastening both pipes together. CONSTITUTION:An outer layer pipe 1 is superposed on an inner layer pipe 2 having its outer surface spirally wound thereon with a space member 9 which is made of a redetermined stainless steel wire 6 and which has been previously incorporated integrally with micro-blocks 7 at predetermined intervals. Accordingly, after the outer layer pipe 1 being superposed on the inner layer pipe 2 with the spacer member 9 therebetween, the outer layer pipe 1 is fastened to the inner layer pipe 2 through the intermediary of the spacer member 9 by an adiabatic diameter reducing process.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to the technical field of multiple pipes such as double pipes used in nuclear power plants and the like.

Summary of the gist> The invention of this application is directed to a multiple tube such as a double tube in which a spiral-shaped micro gap is formed between an inner tube made of stainless steel or the like and an outer tube made of carbon steel or the like. This invention relates to a manufacturing method of the multi-layer tube, in particular, a spacer body having a small continuous cross section such as a linear or spiral shape is formed between the inner tube and the outer tube, and then the inner tube and This invention relates to a multiple pipe with gaps, such as a double pipe, in which the outer pipes are layered relative to each other and both pipes are tightly connected, and a method for manufacturing the same.

<Prior art> As is well known, piping is used in many various industries.
In addition to being used primarily for transporting fluids, it has recently come to be used as a means of transmitting information such as cladding tubes such as cables for transmitting information from structural parts such as doors, etc., and its functions have significantly improved. It's becoming important.

Therefore, depending on the operating conditions, piping has multiple functions such as heat resistance, corrosion resistance, and wear resistance. Current technology has not produced piping that satisfies multiple competing conditions at the same time.For example, in a double pipe (the outer pipe has pressure resistance, heat resistance, and In recent years, the inner tube has come to be used as a multilayer tube or a composite tube with corrosion resistance and abrasion resistance.

Recently, in the field of fluid transport functions, for example, in the nuclear power generation plan 1~, the pharmaceutical industry, the chemical industry, etc., there is a risk of explosions or toxic/poisonous fluids inside and outside the piping. Many piping systems are being used that pose a risk of gas leakage, and therefore, there are also an increasing number of systems that require safety functions.

<Problem to be solved by the invention> However, in conventional cladding, shrink-fitting, etc., the tightness of the inner and outer pipes is maintained even when the tightness is maintained during installation. A method for non-destructively detecting the insulation properties between the inner and outer tubes and the contact and mixing of fluids between the two is available in multiple tubes that are directly connected mechanically to the inner and outer tubes (J
There was the inconvenience of not being able to get it.

<Object of the Invention> The object of the invention of this application is to solve the problems of multiple pipes such as double pipes in which the inner pipe and the outer pipe are directly mechanically contacted and bonded together based on the related art. As a technical issue to be solved, the inner pipe and the multi-layered pipe should be tightly connected with a gap in between and in such a way that no relative displacement occurs during operation, so that the advantages of the multi-layered pipe can be fully utilized. The purpose of this invention is to provide a method (for zero-gap multiple pipes and their production) that is beneficial to the field of piping technology application in various industries.

<Means/effects for solving the problem> In accordance with the above-mentioned purpose, the structure of the invention of this application, which is summarized in the claims of the above patent, is that the inner tube is made of stainless steel or the like in order to solve the problem described above. Equipped with corrosion resistance, on the other hand, is the outer pipe? When manufacturing multiple tubes such as double tubes made of steel or the like that have heat resistance and are tightly connected, at least one of the outer surface of the inner tube and the inner surface of the outer tube, or , integrate a spacer body with a small cross section such as a linear or spiral shape on both sides, and when layering the inner tube and the outer tube relatively, apply a brazing material etc. to the spacer integrally. The inner tube and the outer tube are connected together through a minute gap during relative overlaying, and after the relative overlaying, annular heating is applied to the outer tube before and after the annular heating. , by applying annular cooling to one side, moving the annular heating and annular cooling integrally in the axial direction, and giving the outer tube a fully contracted diameter to more firmly connect the inner tube and the outer tube, A micro gap is formed between them, and during operation, a heat insulating function is provided between the inner tube and the outer tube, and fluid, etc. flows out from the - side of both tubes and comes into contact with the other. This technology is based on a technical means that allows non-destructive detection of these phenomena through the gap when they are mixed or a chemical reaction occurs.

<Principle of the Invention> Next, the principle background of the invention of this application will be explained with reference to the drawings from FIG. 6. As shown in FIG. The inner tube 2 and the inner tube 2 are relatively layered to form a blank tube 3, and then, as shown in FIG. An annular cooling device 5.5 such as a water shower ring is set 1 to 1 in front and back of the axial direction, and the annular heating device 4 and annular cooling device 5.5 are integrally moved relative to each other in the axial direction as shown by the arrow. Then, in the case of the outer tube 1 or a short tube with both ends, the diameter will expand by annular heating, but the expansion diameter will be marked by μ because it is constrained by the annular cooling before and after that.
As shown in FIG. 9, the outer tube 1 has a presser bending moment [
As a result, the outer tube is plastically deformed, and finally yields and is abutted against and tightened to the inner tube 2, forming a bonded double tube over its entire length as shown in FIG.

〈Example〉 Therefore, the first embodiment is based on the basic aspect shown in Fig. 6 and below.
An example of the defense of this application will be explained with reference to Figures 5 to 5.
In the embodiment shown in FIGS. 1 to 1, a subbase body 9 as shown in FIG. The outer tubes 1 made of

Thus, the spacer body 9 is made of a predetermined stainless steel wire 6.
4 minute noises 7'] are integrally formed in advance at predetermined intervals on the outer surface of the inner tube 2. 7. Alternatively, the entire wire including the wire 6 is coated with dofutsuke or the like and wrapped.

After the outer tube 1 is relatively stacked on the inner tube 2 via the spacer body 9, the outer tube 1 is stacked on the spacer body 9 using the adiabatic diameter reduction method shown in the principle basic embodiment shown in FIG. It is made to be tightly connected to the inner tube 2 via.

At this time, by annular heating of the outer tube 1 by a high-frequency induction heating device or the like, the soldering groove 8 is heated between the inner surface of the outer tube 1 and the inner tube 2.
The outer tube 1 and the inner tube 2 are fused to the outer surface thereof and fixed by cooling by annular cooling to promote tightness between the outer tube 1 and the inner tube 2.

At the end of the upper diameter reduction method, a space 4) is formed between the inner tube 2 and the outer tube 1 over the entire spiral gap 10 due to the body 9. 1 and the inner tube 2 are kept in a tight state.

By installing a detection mechanism (not shown) in a predetermined part of the gap 10, it is possible to detect whether the fluid outside the outer tube 1 and the flowing fluid inside the inner tube 2 have leaked and come into contact with each other due to an unexpected situation. In such a case, this can be immediately detected through the gap 10, and heat transfer due to the temperature difference between the inside of the inner tube 2 and the outside of the outer tube 1 during operation can be blocked by the gap 10.

Next, in the embodiment shown in FIG. 5, a bar-shaped spacer body 9' having a small cross section in a row along the axial direction is mechanically formed in advance on the inner tube 2', and the outer tube A concave groove 9'' with a small cross section along the axial direction is also mechanically formed on the inner surface of the tube 2' to prevent the spacer body 9' from interlocking with the concavity ii'7i9''. By layering the tubes 1' relatively and covering them by applying the deep diameter reduction method as described above, a minute gap 10' is formed entirely between the inner tube 2' and the outer tube 1', and The inner tube 2' and the outer tube 1' can be sufficiently connected through the array of spacer bodies 9', and the effects achieved are substantially the same as those of the embodiments described above.

Of course, in this embodiment, it is possible to improve the tightness by coating the inner surfaces of the spacer body 9' and the outer tube 1' with wax, etc.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments. For example, the multiple pipes may be not only double pipes, but also triple pipes, quadruple pipes, or more. Of course it is possible.

In addition, plating or adhesive filling (J, etc.) can be applied instead of brazing filler metal, and the shape of the target multiple pipes is not only straight pipes, but also curved pipes such as pen 1 to pipes. Of course, that is true.

(Effects of the Invention) As described above, according to the invention of this application, basically in multiple pipes such as double pipes, even though the inner pipe and the outer pipe are mechanically connected, there is a cross section between the two pipes. By inserting a small-sized spacer body to form a minute gap,
Even though they are in a tight state, the inner tube and outer tube' are disconnected, so that the insulation function between the two tubes can be maintained, and
Contact or mixing of fluids between the inside of the inner tube and the outside of the outer tube occurs due to an unexpected situation. -C immediately detects this through the gap 1-
It has the excellent effect of being able to take measures to prevent explosions and the generation of toxic scum in advance.

Moreover, since the inner tube and outer tube are connected by a filler metal etc. through the spacer body, there is a possibility that the inner tube and the outer tube may be rubbed relative to each other during operation, despite the existence of a gap. The excellent effect of not having any

Therefore, even if it is difficult and expensive to mechanically form a minute gap between the inner tube and the outer tube in the manufacturing method of multiple tubes, according to the invention of this application, compared to The effect is that this can be done easily.

Therefore, according to the invention of this application, it is difficult to form multiple tubes such as an inner tube and an outer tube or a double tube. pipes,
There is an advantage that multiple pipes etc. that fit together can be formed.

Moreover, by applying the deep diameter reduction method, even if the wax Δ etc. is applied to the spacer body, it is possible to firmly connect the inner tube and the outer tube. It is played.

[Brief explanation of the drawing]

The drawings are detailed explanatory views of the invention of this application, in which Fig. 1 is a partially cutaway perspective view of one embodiment, Fig. 2 is a schematic side view of the spacer body, and Fig. 3 (1) is a schematic side view of the spacer body. FIG. 4 is an enlarged front view of FIG. 1, FIG. 5 is a partially cutaway perspective view of another embodiment, and FIGS. It is a figure. 1... Outer tube, 2... Inner tube, 10... Gap, 9... Spacer body, 4... Annular heating device,
5... Annular cooling device

Claims (2)

[Claims] (1) In a multiple tube in which a gap is formed between the outer tube and the inner tube, a continuous spacer body is interposed between the inner tube and the outer tube to form a gap between the two tubes. A multi-pipe tube with a gap, and both tubes are tightly connected. (2) In a method for manufacturing a multiple tube in which a gap is formed between an outer tube and an inner tube, a continuous spacer body is integrated on at least one of the outer surface of the inner tube and the inner surface of the outer tube. a multilayer tube with gaps, characterized in that the tubes are formed in a relatively layered manner, and then annular heating is applied to the outer tube and annular cooling is applied to at least one of the front and rear portions of the outer tube so as to move in the axial direction. manufacturing method.