JPH03208524A - Multifold pipe separating method - Google Patents

Abstract

PURPOSE:To provide practicability of maintenance and inspection of piping consisting of double pipe etc. heating or cooling properly the specified part on the outside of an outer layer pipe and the inside of an inner layer pipe by a ring-shaped heating device or a ring-shaped cooling device, and thereby separating the inner layer pipe from the outer layer pipe. CONSTITUTION:An outer layer pipe 1 made of carbon steel and an inner layer pipe 2 of stainless steel are put one over the other to form an element pipe 3, and a ring- shaped heating device 4 for ex. of high frequency induction type is set on the outside of the outer layer pipe 1. Ring-shaped cooling devices 5 using showering of service water are set in front of and behind the heating device 4 in its axial direction. These devices 4, 5 are consolidated, and moved relatively in the axial direction of the element pipe 3 and also rotated in the circumferential direction. At this time, the heating width in the axial direction of the element pipe 3 is increased to make dia. expansion of the outer layer pipe 1, or otherwise, cooling device 5 is given to only one side in front of or behind the heating device 4 in its axial direction to narrow the heating width, and thereby the dia. of the inner layer pipe 2 is shrunk. Thus the inner and outer pipes are separated through dia. expansion of the outer layer pipe 1 or through dia. shrinkage of the inner layer pipe 2 so as to allow performance of inspection and maintenance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The disclosed technology belongs to the field of processing technology such as maintenance of piping of double pipes such as double pipes used for various purposes.

Summary of the gist> The invention of this application is, for example, an outer layer tube made of carbon steel and an inner layer tube made of stainless steel, which are relatively layered to form a blank tube, and the outside of the outer layer tube, or Thermal action including heating and cooling is applied to the inside of the inner layer tube in a swirling state, etc., and the outer layer tube and the inner layer tube are stacked by moving and rotating at a predetermined speed relative to the axial direction of the raw tube. This invention relates to a method for separating each layer of a double-layered pipe in which the two are tightly connected by changing the state. In particular, the invention relates to a method for separating each layer of a double-layered pipe in which the two are tightly connected. The annular heating and cooling effects are applied to either or both of the front and rear of the raw pipe, such as showering with tap water, to the front and back of the raw pipe in the axial direction. The outer layer pipe was moved relative to the outer layer pipe and the inner layer pipe was contracted due to the relative movement and further rotation to reduce the circumferential deformation amount, and the pressure bending moment or the warp bending moment was used to expand the diameter of the outer layer pipe and contract the diameter of the inner layer pipe, thereby causing separation between each layer. This invention relates to a method for separating double pipes and is number 5.

<Prior Art> As is well known, piping is not only used primarily for the transportation of gases and liquids, but has also recently been used for mechanical structures such as strength members of buildings and machinery, air chutes, cables, and envelopes. It has come to be used in a wide variety of fields as a means of transmitting information such as materials, and therefore, depending on its use and operating conditions, it has not only a simple transportation function but also has flexibility, heat resistance, corrosion resistance, and wear resistance. W1m functional elements such as these have become strongly required in a state where they overlap and compete with each other, and in addition, once installed, there are cases where the installed state is maintained semi-permanently, and various maintenance inspections and maintenance are required. The reality is that piping that satisfies all of these conditions with a single material is not available using materials based on current science and technology.
To deal with this, for example, the outer layer pipe is made pressure and heat resistant, the inner layer pipe is given corrosion resistance and abrasion resistance, and a middle layer pipe is interposed between them. Double pipes such as double pipes and triple pipes are installed, and not only general straight pipe parts,
It is also designed to be used in the bent pipe portion of the connecting part.

Therefore, in general, in order for these double pipes, etc. in the piping to be laid, to satisfy the functions in the operating state as designed, it is necessary to ensure that the outer layer pipe and the inner layer pipe are connected in such a way that relative displacement does not occur. Despite the strong demand, it is necessary to observe and analyze changes in the inner and outer layer pipes over time during the above-mentioned maintenance inspections, changes in operating conditions, etc., and in some cases, inject fillers between them. , from the need to detect gas leaks,
There are now cases where it is necessary to separate the outer and inner tubes, and even the middle layer, to create a sense of separation. This is required for the pipe and the inner layer pipe, etc., and a strong requirement for one side to be tightly bound has the disadvantage of inhibiting subsequent peeling.

<Problem to be solved by the invention> Therefore, in manufacturing double pipes, etc., after the outer layer pipe and the inner layer pipe are relatively layered, there are many methods such as shrink fitting method, cold fitting method, cladding, etc. As mentioned above, is there any combination technology?
Mutual peeling of the outer layer pipe and inner layer pipe after installation is generally not expected, so the initial design did not take into account separation or peeling after operation, and only the means of tightening was developed.
Therefore, if the former of bonding and peeling is utilized, the latter is inconveniently sacrificed.

In the case of fitted double pipes, etc., the only way to separate and take out the inner and outer pipes for repair, inspection, remanufacturing, etc. is through mechanical processing such as cutting. There are limits to the application of machining to pipes, etc., and anything other than the pipes that are taken out becomes scrap, which cannot be recycled and is a negative resource.

In particular, nuclear power plants or factories such as heavy and chemical industries and chemical industries! In terms of installation, it is virtually impossible to connect only straight pipes due to the connection with peripheral equipment facilities and the narrow site conditions, so it is difficult to use bent pipes such as bent pipes for connections. Therefore, despite the ever-increasing need for the separation technology described above, it is extremely difficult to implement, and once the piping has been installed, it cannot be easily disposed of or replaced due to cost. Therefore, there was a strong demand for the emergence of an original separation and peeling technology to deal with this problem.

<Objective of the Invention> The object of the invention of this application is to manufacture and operate double-walled pipes such as double-walled pipes using the current technology of material development based on the above-mentioned prior art.
Also, it is a technical issue to solve the problem of not being able to separate the outer layer pipe and the inner layer pipe during subsequent maintenance.
The tightening of the outer layer pipe and the inner layer tube during manufacturing can be done freely in the straight pipe section or the bent pipe section in the same manner as in the conventional method, and moreover, the tightened state that can be opened during operation can be maintained reliably. However, we would like to provide an excellent method for separating double-walled pipes that can be used to freely separate the outer layer pipe, inner layer pipe, and even the middle layer during maintenance periods after operation, thereby benefiting the fields in which piping technology is used in various industries. It is something to do.

In order to solve the above-mentioned problems, II4rfc of the invention of this application, which has the gist of the above-mentioned claims in accordance with the above-mentioned purpose, has the following features:
An outer layer tube made of carbon steel or the like and an inner layer tube made of stainless steel or the like are layered relative to each other via an intermediate layer tube such as ceramics depending on the configuration to form a base tube, and a high frequency induction heating device is installed on the outside of the outer layer tube and inside the inner layer tube. At the same time, a pair of annular cooling devices such as tap water shower rings are attached to the front and back of the relatively layered raw pipe in the axial direction to move the raw pipe relative to each other in the axial direction, and depending on the design, relative rotation is possible. In order to suppress the amount of deformation in the circumferential direction, in this case, the diameter of the outer tube is expanded by widening the heating width in the axial direction of the raw tube during annular heating, and the expansion diameter of the outer tube is By providing an annular cooling device only on one side and narrowing the heating width in the axial direction, the inner layer tube can be reduced in diameter, the outer layer tube can be expanded in diameter relative to the inner layer tube, and the inner layer tube can be expanded relative to the outer layer tube. Technical measures have been taken to allow for flexible inspections, inspections, and maintenance by reducing the diameter and peeling and separating the outer and inner tubes.

<Example> Next, an example of the invention of this application will be described below with reference to the drawings.

First, the embodiment shown in Figs. 1 to 4 is an embodiment of manufacturing a bonded double pipe by reducing the diameter of the outer layer pipe with respect to the inner layer pipe, and is shown as a premise for the separation and peeling described below.As shown in Fig. 1, For example, while the outer layer tube 1 is made of carbon steel, the inner layer tube 2 is made of stainless steel.
The outer layer tube 1 is layered in a relatively layered manner to form the blank tube 3 in advance, and then, as shown in FIG. Furthermore, an annular cooling device 5 is provided with a cooling device using tap water showering at a predetermined interval before and after the annular heating device 4 in the axial direction.
The annular heating device 4 and the annular cooling device 5 are integrated via a suitable bracket or the like, and are moved relative to the raw pipe 3 in the axial direction and rotated in the circumferential direction by a predetermined drive device.

In this embodiment, if the portion of the outer layer tube 1 corresponding to the annular heating device 4 is a short cylindrical portion of a predetermined length, and the front and rear ends thereof are free ends, the short cylindrical portion The outer tube 1 attempts to freely expand in diameter by the annular heating action, but
Since a cooling effect is imparted by the showering of tap water in the annular cooling device M5 before and after the annular cooling device M5, its expansion diameter is restrained, it gradually deforms plastically, and finally yields, as shown in Fig. 3. A presser bending moment F is applied to the expansion diameter of the outer layer tube 1 and acts to press it against the inner layer tube 2 side, and the annular heating device 4 and the annular cooling device 5 move relative to the base tube 3. As a result, the thermal history due to such thermal action extends to the entire area of the base pipe 3, and therefore, due to the annular cooling before and after the annular heating, the outer layer pipe 1 is reduced in diameter as shown in FIG. Then, it is fitted onto the inner layer pipe 2 and tightly tied to obtain a substantially fastened double pipe 6.

In this case, if the axial heating width of the blank tube 3 by the annular heating device 4 is narrowed, the cooling history by the annular cooling device 5 will be longer, and the fitting loss due to tightening can be increased.

In this way, the fastened double pipe 6 as a double pipe is obtained.

Next, the embodiment shown in FIGS. 5 to 7, which is the main point of the invention of this application, is that the outer layer tube 1 of the double tube 6 is formed by the expanded diameter of the outer layer tube 1.
This is a mode of relative separation due to peeling of the inner layer tube 2, and as shown in FIG. In the case where the double pipe 6 is in a fastened state as a double pipe, an annular heating device 4 as a high frequency induction heating device is installed outside a predetermined portion of the outer layer pipe 1 of the fastened double pipe 6 shown in FIG. set, an annular cooling device 5 of the tap water showering device is provided only on one side in the axial direction of the raw pipe 3, and the annular heating device 4 and the annular cooling device 5 are connected and integrated with a suitable bracket or the like,
The outer layer tube 1 of the annular heating device 4 is moved at a set speed relative to the base tube 3 in the axial direction and rotated in the circumferential direction to suppress the amount of deformation caused by temperature unevenness in the circumferential direction.
Because the outer layer tube 1 and the inner layer tube 2 are in a tight state due to the annular cooling action of the annular cooling device 5 before or after passing relative to each other on the outside of the A pressing force is applied to the outer layer tube 1 on the side of the heating device 4 against the side of the inner layer tube 2, whereas on the side of the annular heating device 4, due to the expansion action, it gradually deforms plastically, and finally Due to the yielding, a bending moment F' acts on the outer layer tube 1 as shown in FIG. 6, and the annular heating device 4,
Due to the relative movement of the annular cooling device 115 in the axial direction with respect to the base tube 3, the warping moment ``' extends to the entire area of the outer layer tube 1, and as a result, as shown in FIG. As the cooling device M5 passes through the base tube 3, the diameter of the outer layer tube 1 expands and a peeling action is performed on the inner layer tube 2.

In this way, the outer layer tube 1 is peeled (separated) from the inner layer tube 2, and an appropriate filler is press-fitted into the gap defined between the two, an air leak test is performed, and the outer layer tube 1 and the inner layer are separated. It becomes possible to inspect the surface of the pipe 2, etc.

Incidentally, it goes without saying that the embodiment of the invention of this application is not limited to the above-mentioned embodiments. For example, the separation of the outer layer pipe and the inner layer pipe may be performed by expanding the outer layer pipe 1 shown in FIGS. 5 to 7 above. In addition to peeling due to the diameter, the diameter reducing action shown in FIGS. 1 to 4 is applied to the inner layer tube 2 side, that is, the annular heating device M4 and the annular cooling device 5 are appropriately set inside the inner layer tube 2. By moving and rotating the inner layer tube No. 3, the inner layer tube 2
It is also possible to separate from the inside of the outer layer tube 1 by reducing the diameter inward, and conversely, for the separation of the outer layer tube 1 and the inner layer tube 2 of the double tube 6, a diameter reduction action is applied to the inner layer tube side, i.e. By applying the configuration shown in FIGS. 1 to 4 to the inner layer tube 2 side, the inner layer i! 2 is reduced in diameter with respect to the outer layer tube 1 side, and the outer M tube 1 is expanded in diameter to achieve the effects of both. Of course, it is also possible to separate them by peeling them together, and furthermore, it is possible to create a three-layer separated state by expanding the diameter of the outer layer tube 1 and contracting the diameter of the inner layer tube 2 with respect to the middle layer tube. Various aspects can be adopted, such as the following.

According to experiments, it has been found that widening the axial heating width of the annular heating is effective for peeling and separation.

And, in terms of numerical analysis data, the outer diameter is φ165.2mm,
For a carbon steel pipe with a wall thickness of 5.5InIn, the longer the axial heating width of annular heating, the more difficult it is to shrink the diameter.For example, when the heating width is 81rIII, the diameter reduction rate is 0.3%. On the other hand, the temperature increase width is 201 rI! The same 0. 03
It was found that only % diameter reduction effect could be obtained.

It should be noted that the outer layer tube, inner layer tube, and even middle layer tube that are the object of the invention of this application can be made of not only carbon steel and stainless steel, but also ceramic tubes, synthetic resin tubes, and various other materials. Of course.

Moreover, it goes without saying that the target pipe body is applicable not only to straight pipes but also to curved pipes.

(Effects of the Invention) As described above, according to the invention of this application, basically double-layered pipes, etc., in which carbon steel outer-layer pipes and stainless steel inner-layer pipes are layered relative to each other via ceramic middle-layer pipes, etc. In the pipe, annular heating such as high-frequency induction heating is applied to a predetermined area on the outside of the outer layer pipe or inside the inner layer pipe, and an annular cooling device such as a shower ring using tap water is installed on at least one of the front and rear sides in the axial direction. The diameter of the outer layer tube is expanded through the presser bending moment by applying a rotational action and relative movement in the axial direction with the double layer tube to suppress the amount of deformation caused by temperature unevenness in the circumferential direction. The strong connection between the outer layer tube and the inner layer tube can be maintained by peeling the two tubes relative to each other, and by setting an annular cooling device on one side of the annular heating device in the axial direction, the inner layer can be strengthened through the bending moment. It is possible to reduce the diameter of the tube and separate it from the outer layer tube, and furthermore, the inner layer tube can be separated from the outer layer tube through the presser bending moment and warp bending moment caused by these annular heating and annular cooling. Release the binding through diameter reduction and peel off both tubes through the expanded diameter of the outer layer tube from the inner layer tube, perform these on the middle layer tube to reliably promote separation from the tightening, By promoting peeling, we perform relative peeling of the outer layer pipe and inner layer pipe of a bonded double pipe with sufficient fitting allowance to treat the interface between the two and perform press-fitting filler leak inspection, etc. The great effect of being able to do things freely is amazing.

Therefore, there is no longer the inconvenience of having only the conditions at the time of manufacturing the fastened double pipe and not being able to deal with maintenance during operation or after the fact, as in the past. The excellent effect of being able to separate the pipes of each layer is achieved.

Moreover, these treatments involve relatively overlapping outer layer pipes and inner layer pipes,
Furthermore, since it can be carried out selectively depending on the thermal history of the middle layer pipe, it has the effect of significantly improving the degree of freedom in design and construction. Since there is no influence, there is also the effect of increasing the degree of freedom in material selection.

Therefore, there is no inconvenience that the maintenance operation conditions are restricted depending on the use of the piping, as in conventional systems, and an excellent effect is achieved in that the piping can be laid and maintained and inspected freely from beginning to end.

[Brief explanation of drawings]

The drawings are explanatory diagrams of embodiments of the invention of this application, and are
Figure 4 is a diagram of a double-walled pipe that is tightened by diameter reduction, Figure 1 is a relative cross-sectional view of the outer layer pipe and inner layer pipe, Figure 2 is a cross-sectional view of the thermal history imparted, and Figure 3 is a cross-sectional view of the pressure bending moment. Schematic perspective view,
Fig. 4 is a sectional view showing the appearance of tightness, Figs. 5 to 7 are examples of peeling due to expansion diameter of the outer layer pipe, Fig. 5 is a partial sectional view of thermal history imparting, and Fig. 6 is a schematic diagram of warping moment. Perspective view, No. 7
The figure is a partial cross-sectional view of a double-layer tube in which the outer layer tube and the inner layer tube are layered relative to each other after treatment. 1... Outer layer pipe 2... Inner layer pipe 3... Base pipe
4... Annular heating device 5... Annular cooling device
6... Double pipe F... Presser bending moment F'... Warp bending moment,'' →

Claims (8)

[Claims] (1) In a method of separating a double layer pipe by separating each layer of the double pipe having an outer pipe layer and an inner pipe layer, the diameter of the outer layer pipe is expanded from the layered state, and the inner layer pipe is contracted from the layered state. A method for separating double pipes, characterized in that at least one of the steps of reducing the diameter is performed. (2) The diameter of the inner layer tube is reduced by annular heating of the inner wall of the tube and annular cooling at least one of the front and rear sides in the axial direction.
Duplicate pipe separation method described in section. (3) The double pipe separation method according to claim 2, wherein the annular heating and annular cooling are performed by rotating in the circumferential direction and moving in the axial direction. (4) The method for separating multiple tubes according to claim 1, characterized in that the diameter of the outer layer tube is expanded by annular heating and annular cooling either before or after the axial direction. (5) The double pipe separation method according to claim 4, wherein the annular heating and annular cooling are performed by rotating in the circumferential direction and moving in the axial direction. (6) The method for separating a double pipe according to claim 1, wherein the double pipe has an outer layer pipe, an inner layer pipe, and a middle layer pipe inside both the pipes. (7) The double pipe separation method according to claim 1, wherein the double pipe is composed of a double pipe including an outer layer pipe and an inner layer pipe. (8) The double pipe separation method according to claim 1, wherein the double pipe is a tied pipe.