JPH0741476B2 - Double tube separation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to a processing technology field such as maintenance of piping of a double-walled pipe or the like, which is used for various purposes.

<Summary of Summary> Therefore, the invention of this application is, for example, a carbon steel outer layer tube and a stainless steel inner layer tube are relatively laminated to form a raw tube, and the outer layer tube is provided outside, or A heat action including heating and cooling is applied to the inside of the inner-layer pipe in a swirling state, etc., and the outer-layer pipe and the inner-layer pipe are layered so as to move and rotate in the axial direction of the raw pipe relatively at a predetermined speed. It is an invention relating to a method for separating each layer pipe of a double-layered double-layered pipe that is tightly connected to each other by changing the state, and in particular, a heating device or the like is provided outside the outer-layered pipe of the double-layered pipe or inside the inner-layered pipe. And the cooling action of the shower ring or the like with tap water is applied to either the front or rear, or both, in the axial direction of the shell. Relative movement, and further rotation to reduce circumferential deformation, presser bending moment, Alternatively, the invention relates to a method for separating a double-layered pipe in which the outer layer pipe is expanded and the inner layer pipe is contracted by a bending moment to separate the layers.

<Prior Art> As is well known, pipes are not only used for the primary purpose of transporting gas and liquid, but recently, mechanical structures such as strength members of buildings and mechanical devices, air shooters, cables, and As a means of transmitting information such as packaging materials, it has come to be used in various fields in various ways. Therefore, it is not only a transport function, but also flexibility, heat resistance, corrosion resistance, and abrasion resistance depending on the usage condition and operating conditions. There is a strong demand for complex functional elements such as characteristics, etc., in a state of overlapping and competing with each other, and in addition, there is a case where the installed state is maintained semipermanently after being installed, but various maintenance inspections are required. There are many places where maintenance such as maintenance is required, and it is the actual situation that piping that can satisfy all these conditions with one material has not been obtained with materials based on science and technology at this stage. To deal with this, for example, the outer layer pipes should be pressure and heat resistant, the inner layer pipes should be provided with corrosion resistance and wear resistance, and the middle layer pipes should be interposed between them. A double-layer pipe such as a pipe is provided, and it is adapted to be used not only for a general straight pipe portion but also for a bent pipe portion of a connecting portion.

Therefore, in order to satisfy the function in the operating state as designed, the double pipes in the laying pipe are generally in such a tightly connected state that the relative displacement between the outer layer pipe and the inner layer pipe does not occur. Despite strong demands, the time-dependent changes in the inner and outer layer pipes may be observed and analyzed during the above-mentioned maintenance and inspections, changes in operating conditions, etc. In some cases, it may be necessary to separate the outer layer tube and inner layer tube, and further the intermediate layer to separate them from each other because of the need to detect Conditions contradictory to the above are required for the outer layer pipe and the inner layer pipe, and the strong requirement for tightness on one side has a disadvantage that it hinders subsequent peeling.

<Problems to be Solved by the Invention> Thus, in the production of double pipes, etc., after the outer layer pipe and the inner layer pipe are relatively overlaid, the shrink fitting method, the cold fitting method, etc., the clad, etc. There is a combination technology of, but as mentioned above,
The mutual separation of the outer layer pipe and the inner layer pipe after laying is generally not expected at all, so the initial design does not incorporate separation or peeling after operation, and only the fastening means is developed.
Therefore, if the former of the binding and peeling is utilized, the latter is disadvantageous in that it is sacrificed.

And, in case of fitting double pipe etc., there is only mechanical processing means such as cutting and cutting to separate and take out the inner and outer pipes for repair, inspection, regeneration, etc. However, there was a limit to the application of mechanical processing, and except for the pipe to be taken out, it became scrap, and recycling was ineffective and it was a negative resource.

Especially, in nuclear power plants or factory facilities such as heavy chemical industry and chemical industry, it is practically impossible to pipe only straight pipes due to the interaction with peripheral equipment facilities and narrow site conditions. In many cases, bent pipes such as vent pipes are used in the connecting portion. Therefore, although the separation technology by peeling described above has a growing need for it, its implementation is extremely difficult. Piping cannot be easily discarded and replaced from the viewpoint of cost, and there has been a strong demand for the emergence of an original separation and peeling technology to cope with this.

<Object of the Invention> The object of the invention of the present application is from the production of a double pipe such as a double pipe according to the state of the art of the material development based on the above-mentioned prior art to the operation,
And, as a technical problem to be solved, the problem that the outer layer pipe and the inner layer pipe cannot be separated and separated in the subsequent maintenance,
The outer layer pipe and the inner layer pipe at the time of manufacturing can be freely connected to the straight pipe part or the bent pipe part in the same manner as in the conventional manner, and moreover, the tightly connected state can be surely maintained during the operation. , The outer layer pipe and inner layer pipe at the time of maintenance after operation, etc., and also the separation of the intermediate layer can be freely performed to provide an excellent method for separating double-layer pipes that is useful in the field of piping technology application in various industries. It is a thing.

<Means and Actions for Solving the Problems> In order to solve the above-mentioned problems, the structure of the invention of the present application, which is based on the above-mentioned object and has the above-mentioned claims as its gist, is made of an outer layer pipe made of carbon steel or the like and a stainless steel pipe. Depending on the mode, inner layer pipes such as the above are relatively laminated through a middle layer pipe such as ceramics to form a raw pipe, and annular heating is applied to the outside of the outer layer pipe or the inside of the inner layer pipe by a high frequency induction heating device, etc. An annular cooling device such as a pair of tap water shower rings is attached to the front and rear in the axial direction of the laminated pipes to relatively move in the axial direction of the pipes, and depending on the design, relative rotation is performed to suppress the circumferential deformation amount,
At that time, the annular heating is performed to widen the axial heating width of the raw pipe to expand the outer pipe, or the annular cooling device is provided only on at least one side of the axial direction of the raw pipe of the annular heating device. By narrowing the heating width in the axial direction, the inner layer pipe is reduced in diameter, the outer layer pipe is expanded relative to the inner layer pipe, and the inner layer pipe is reduced in diameter relative to the outer layer pipe. It is provided with a technical means such that the pipe can be separated and separated so that predetermined inspection and maintenance can be performed.

<Embodiment> An embodiment of the invention of this application will be described below with reference to the drawings.

First, the mode shown in FIGS. 1 to 4 is a mode of manufacturing a tightly bonded double pipe by reducing the diameter of the outer layer pipe with respect to the inner layer pipe, which is shown as a premise of separation and peeling described below, and as shown in FIG. For example, a stainless steel inner layer tube 2 is relatively laminated to a carbon steel outer layer tube 1 to form a raw tube 3 in advance, and then, as shown in FIG. 2, at an axial predetermined portion of the outer layer tube 1. Set an appropriate annular heating device 4 such as a high frequency induction heating device on the outside thereof,
Further, a cooling device using a shower ring of tap water is set as an annular cooling device 5 at a predetermined interval in the axial direction of the annular heating device 4 and the annular heating device 4 and the annular cooling device 5 are provided with appropriate brackets or the like. It is integrated through the above and is moved relative to the raw pipe 3 in the axial direction by a predetermined driving device and is rotated in the circumferential direction.

Thus, in the aspect, when the portion of the outer layer tube 1 corresponding to the annular heating device 4 has a short cylindrical shape with a predetermined length and the front and rear ends thereof are free ends, the short cylindrical portion The outer tube 1 of No. 1 tries to expand its diameter by the annular heating action,
Since the cooling action is given by the tap water shower ring of the annular cooling device 5 before and after that, the swelling diameter is restricted, gradually plastically deforms, and finally descends, as shown in FIG. A pressing bending moment F is applied to the expanded diameter of the outer layer tube 1 so as to press the outer layer tube 1 toward the inner layer tube 2 side, and moreover, the annular heating device 4 and the annular cooling device 5 are relative to the base pipe 3. By being moved, the heat history due to such heat action spreads over the entire region of the elementary pipe 3, and therefore the outer layer pipe 1 is reduced in diameter by the annular cooling before and after the annular heating as shown in FIG. Then, the inner layer tube 2 is fitted and tightly bonded to obtain a substantially tightly bonded double tube 6.

In this case, if the axial heating width of the annular heating device 4 with respect to the raw pipe 3 is narrowed, the cooling history by the annular cooling device 5 is longer and the fitting margin due to the tight connection can be increased.

In this way, the tightly connected double tube 6 as a double tube is obtained.

Next, the embodiment which is the center of the gist of the invention of this application shown in FIGS. 5 to 7 is the outer layer tube 1 of the double tube 6 due to the expanded diameter of the outer layer tube 1.
As shown in FIG. 4, the outer pipe 1 made of carbon steel and the inner pipe 2 made of stainless steel are laminated relatively to each other to form a double pipe 3 as shown in FIG. In the case where the double tube 6 is in the tightly closed state of the heavy tube, the annular heating device 4 as a high frequency induction heating device is set outside the predetermined portion of the outer layer tube 1 of the tightly connected double tube 6 of FIG. Then
The annular cooling device 5 of the tap water showering device is provided only on one axial side of the raw pipe 3, and the annular heating device 4 and the annular cooling device 5 are connected and integrated by an appropriate bracket or the like to form the raw pipe 3 and the axial direction. Before moving relative to the outside of the outer layer tube 1 of the annular heating device 4, by moving at a set speed and rotating in the circumferential direction to suppress the amount of deformation caused by temperature unevenness in the circumferential direction, or Since the outer layer pipe 1 and the inner layer pipe 2 are in contact with each other in advance due to the annular cooling action of the annular cooling device 5 later, the outer layer pipe 1 on the side of the annular heating device 4 to be expanded has an inner layer pipe. On the other hand, the pressing force acts on the 2 side, and on the other hand, the annular heating device 4 side is gradually plastically deformed due to the expansion effect, and finally is deformed to the outer layer tube 1 together. As shown in FIG. 6, the warp bending moment F ′ Further, due to the axial movement of the annular heating device 4 and the annular cooling device 5 relative to the raw pipe 3, the warp bending moment F ′ extends over the entire area of the outer layer pipe 1 and, as a result, is shown in FIG. In this way, as the annular heating device 4 and the annular cooling device 5 pass through the raw pipe 3, the outer layer pipe 1 expands and the inner layer pipe 2 is separated.

In this way, the outer layer tube 1 has a peeling (separating) action with respect to the inner layer tube 2, and an appropriate filler is press-fitted into a gap formed between the outer layer tube 1 and the outer layer tube 1 or the inner layer tube after air leak inspection or separation. It is possible to perform the surface inspection of item 2 and the like.

Needless to say, the embodiment of the invention of this application is not limited to each of the above-mentioned embodiments. For example, regarding the separation of the outer layer pipe and the inner layer pipe, the expanded diameter of the outer layer pipe 1 shown in FIGS. In addition to the separation by the above, the diameter reducing action shown in FIGS. 1 to 4 is given to the inner layer pipe 2 side, that is, the annular heating device 4 and the annular cooling device 5 are appropriately set inside the inner layer pipe 2. It is also possible to separate from the inner side of the outer layer tube 1 through the inner diameter reduction of the inner layer tube 2 by moving the inner tube 3 relative to and rotating it, and conversely, to the outer layer tube 1 and the inner layer of the double tube 6. Regarding the separation of the tube 2, the inner layer tube 2 is provided with a diameter reducing action, that is, by applying the embodiment shown in FIGS.
Can be separated by reducing the diameter of the outer layer tube 1 to the outer layer tube 1 side and expanding the outer layer tube 1 with the action of both to separate them. It is needless to say that the three-layer separated state can be revealed by reducing the diameter of the inner layer tube 2, and various modes can be adopted.

Then, according to the experiment, it was found that it is effective to widen the axial heating width of the annular heating for the peeling separation.

The numerical analysis data shows that the outer diameter is 165.2 mm and the wall thickness is 5.5 m.
For a carbon steel pipe of m, the longer the axial heating width of the annular heating is, the more difficult it is to reduce the diameter.For example, when the heating width is 8 mm, the diameter reduction ratio is 0.3%, whereas the heating width is 20mm is the same
It was found that only a 0.03% diameter reduction effect was obtained.

The outer layer pipe, the inner layer pipe, and the middle layer pipe, which are the objects of the invention of this application, are not limited to carbon steel and stainless steel, but ceramic pipes, synthetic resin pipes, and other various materials can be used. Of course.

Further, it goes without saying that the target pipe body can be applied not only to a straight pipe but also to a curved pipe or the like.

<Effects of the Invention> As described above, according to the invention of this application, basically, a double-walled pipe or the like in which an outer-layer pipe made of carbon steel or an inner-layer pipe made of stainless steel is relatively layered through a middle-layer pipe made of ceramics, etc. In the pipe, outside the outer layer pipe or inside the inner layer pipe, annular heating such as high frequency induction heating is provided, and at least one of the axial front and rear thereof is provided with an annular cooling device such as a shower ring with tap water. The outer layer pipe is expanded through the presser bending moment by setting and setting the axial relative movement with the double-layer pipe and further applying the rotating action to suppress the deformation amount caused by the temperature unevenness in the circumferential direction. By firmly separating the outer layer pipe and the inner layer pipe from each other by peeling the two pipes relative to each other, or by setting the annular cooling device on one side in the axial direction of the annular heating device, the inner layer can be bent through the warp bending moment. Reduce the diameter of the pipe to the outside It can be separated (separated) from the layered pipe, and further, the presser bending moment by these annular heating and annular cooling, and the contraction of the inner layer pipe to the outer layer pipe through the warp bending moment. Release the tightness and separate both tubes through the bulge of the outer layer tube to the inner layer tube, or perform these to the middle layer tube to surely promote separation from tightness or promote separation. By doing so, it is possible to perform relative separation between the outer layer tube and the inner layer tube of a tightly-coupled double tube that has a reliable and sufficient fitting margin, to process the boundary surface between them and to press fit the filler and inspect gas leaks. The excellent effect that it can be performed is exhibited.

Therefore, there is no inconvenience that there is only the condition at the time of manufacturing the tightly-coupled double pipe as in the past, and it is not possible to deal with the operation or the post-maintenance. An excellent effect is obtained in that each layer tube can be separated.

Moreover, these treatments are performed with the outer layer pipe and the inner layer pipe that are relatively overlaid.
Furthermore, since it can be selectively performed depending on the heat history for the middle-layer pipe, it has the effect of significantly improving the degree of freedom in design and construction. Moreover, the heat history depends on the materials of the outer-layer pipe and the inner-layer pipe. Since it is not affected, there is an effect that the degree of freedom in material selection is increased.

Therefore, unlike the conventional mode, there is no inconvenience that the maintenance operation condition is restricted by the use of the pipe, and the excellent effect that the laying and maintenance inspection of the pipe can be freely performed from beginning to end is exhibited.

[Brief description of drawings]

Drawing is an explanatory view of the embodiment of the invention of this application,
Fig. 4 is an embodiment of a tightly-coupled double pipe by reducing the diameter. Fig. 1 is a cross-sectional view of relative layers of an outer layer pipe and an inner layer pipe, Fig. 2 is a heat history imparting cross-sectional view, and Fig. 3 is a pressing bending moment. Schematic perspective view,
FIG. 4 is a cross-sectional view showing the tight binding, FIGS. 5 to 7 are examples of separation due to the bulging of the outer layer pipe, FIG. 5 is a partial cross-sectional view for imparting heat history, and FIG. 6 is a schematic diagram of the warp bending moment. Perspective view, 7th
The figure is a partial cross-sectional view of a double tube element tube in which an outer layer tube and an inner layer tube after treatment are relatively laminated. 1 ... Outer layer tube, 2 ... Inner layer tube 3 ... Element tube, 4 ... Annular heating device 5 ... Annular cooling device, 6 ... Double tube F ... Pressing bending moment F '... Warp bending moment

Claims (8)

[Claims] 1. A method for separating a multi-layer tube by separating each layer tube of a multi-layer tube having an outer tube layer and an inner tube layer, in which the outer layer tube is expanded from a multi-layered state and the inner layer tube is multi-layered. A double-heavy tube separation method, characterized in that at least one of the processes for reducing the diameter is performed. 2. The inner diameter of the inner layer pipe is reduced by annular heating of the inner wall of the pipe and annular cooling of at least one of the front and rear in the axial direction of the inner wall. Double tube separation method. 3. The double tube separation method according to claim 2, wherein the annular heating and the annular cooling are performed by rotating in the circumferential direction and moving in the axial direction. 4. The double tube separation method according to claim 1, wherein the expansion diameter of the outer layer tube is controlled by annular heating and annular cooling either forward or backward in the axial direction. 5. A double-heavy tube separation method according to claim 4, wherein the annular heating and the annular cooling are performed by rotating in the circumferential direction and moving in the axial direction. 6. The double-layered pipe has an outer layer pipe, an inner layer pipe, and a middle layer pipe in both pipes.
The method for separating a double-heavy pipe according to the item. 7. The method for separating a double-layered pipe according to claim 1, wherein the double-layered pipe is a double pipe of an outer-layer pipe and an inner-layer pipe. 8. The method for separating a double-heavy pipe according to claim 1, wherein the double-heavy pipe is a tightly closed pipe.