JPH01118306A - Manufacture of tightly bonded multi-layer pipe - Google Patents

Abstract

PURPOSE:To contract an outer pipe at equal intervals in the circumferential direction and to obtain a tightly bonded multi-layer pipe by putting the outer pipe on an inner pipe through an annular clearance and setting a plurality of local heating devices and local cooling devices in the circumferential direction and in the axial direction but at least in the former direction and relatively traveling them. CONSTITUTION:A long-sided corrosion-resistant inner pipe 1 is put on a pressure- resistant outer pipe 2 through an annular clearance 3. Then, a heating and cooling equipment 10 is set wherein a compression roller 9, a heating device 4 and a cooling device 5 right behind the heating device are arranged coaxially at the initial part of the outer pipe 2 from the front in the forward direction to the ring holder, linearly in the axial direction and at the circumferential positions divided into four equal parts or by 90 degrees. When the heating and cooling equipment 10 is traveled in parallel at a prescribed speed, the local heating by each heating device 4 expands the diameter of the outer pipe 2, expansion to the inside is performed by the compression roller 9 and, immediately after that, the pipe is cooled forcedly by each cooling device 5.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology is used to construct piping for corrosive fluids such as crude oil transport pipes by using a corrosion-resistant inner pipe made of stainless steel or the like and a pressure-resistant outer pipe made of carbon steel or the like. It belongs to the field of manufacturing technology for multilayer pipes such as double pipes that are mechanically connected.

<Summary of the gist> Accordingly, the present invention involves laminating an inner tube made of stainless steel or the like over an outer tube made of carbon 81111 or the like, and applying local heating to the outer tube from one end using a burner or the like. The outer tube is expanded by applying it while moving at a predetermined speed in the axial direction,
Immediately after that, a cooling means such as a shower ring is applied to cool the area so as to follow the local heating, thereby causing the outer tube to contract in the circumferential direction relative to the inner tube, thereby tightening the inner tube and the outer tube. This invention relates to a method for manufacturing a multilayer pipe, and in particular,
The local heating means and the cooling means are arranged in a predetermined number in the circumferential direction of the outer tube, or in the circumferential direction and the axial direction, and are moved in the axial direction at a set speed. This invention relates to a method for manufacturing a fastened multilayer pipe in which the inner pipe and the outer pipe are more reliably fastened by applying expansion and contraction to a plurality of parts.

<Prior Art> As is well known, piping is used not only as a means of transporting fluids, but also as a main component of building structures and, more recently, as a means of transmitting information.
The functions of piping such as crude oil transport pipes under complex and harsh environmental conditions have lost their primitive simplicity and are now required to have double-cone functions.

In other words, for cooling, etc., functions are required that have corrosion resistance against corrosive fluids and pressure resistance against earthquakes, temperature changes, etc., and in order to cope with conflicting characteristics depending on the conditions, the inner tube is made of stainless steel, which has high corrosion resistance. There is an increasing demand for multi-layered pipes, such as double pipes, in which the inner tube is made of carbon steel and the outer tube is made of carbon steel, which has excellent pressure resistance, and these are closely integrated.

For example, cladding means, shrink fitting means, etc. are available for manufacturing through multi-layered tubes such as double tubes in which the inner and outer tubes of the nuclide are closely integrated, but the equipment, conditions, etc. In addition, from the viewpoint of cost, etc., methods for mechanically connecting the inner tube and the outer tube by layering them relative to each other through a predetermined ring-shaped clearance have recently been actively developed. Gansho 39
As seen in the invention No. 47817, as shown in Fig. 9.10, an inner tube 1 made of stainless steel is layered on an outer tube 2 made of carbon steel through a predetermined ring-shaped clearance 3, and A burner 4 is positioned spot-wise at the starting end of the tube 2 and heated by moving along the axial direction at a predetermined speed to impart a change in diameter to the bulge. Immediately thereafter, a cooling device 5 such as a shower ring is applied. By moving this spot-like thermal change portion 6 in the axial direction at a predetermined speed, the outer tube 2 is
A technique has been developed in which the double tube 7 is obtained by tightly connecting the double tube 7 to the inner tube 1 in the circumferential direction.

<Problems to be Solved by the Invention> However, in the conventional technology, the spot-shaped heat change portion 6 is at one point in the circumferential direction, and the heat change portion 6 moves in the axial direction over time. It is true that basically the inner tube 1 and the outer tube 2 are tightly connected in the circumferential direction, but when the outer surface of the inner tube and the inner surface of the outer tube start to come into contact, a gradually increasing friction occurs between them, and the There is a drawback that a uniform tightening state is not achieved, and if unevenness occurs in the axial direction over time, the double pipe 7
There was a problem that the tightness distribution of the body was uneven.

Therefore, as a result, there is a fear that the double pipe as a product may have problems in terms of product reliability.

<Object of the Invention> The object of the present invention is to provide an economical advantage of the axial movement of a spot-like heat changing part, which eliminates the need to perform a heating action or a cooling action on the entire circumference and surface based on the above-mentioned conventional technology, and an apparatus. While taking advantage of the simplification of the structure, the tightening in the circumferential direction during the contact process between the outer surface of the inner tube and the inner surface of the outer tube is uniform, and as a result, the tightening in the axial direction is also uniform. The purpose of this invention is to provide an excellent method of manufacturing a fastened multilayer pipe that can more reliably obtain product reliability and benefit piping technology applications in various industries.

<Means/effects for solving the problems> In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned claims, is based on the inner tube made of corrosion-resistant stainless steel or the like. Pressure-resistant outer tubes made of carbon steel or the like are stacked relatively one on top of the other through a ring-shaped clearance, and then a predetermined distance is formed in the circumferential direction, or in the circumferential direction and the axial direction at the starting end of the outer tube. The heating means and cooling means are set back and forth in the axial direction at intervals, and then the set heating means and cooling means are moved in parallel in the axial direction as a whole at a set speed, and in the process, a set number of circumferential The heating means performs local heating in a spot-like manner to make the outer tube change in the radial direction into an expanded state, and then, following this, the cooling means forcibly cools the outer tube using a shower ring or the like to surround the outer tube immediately after expansion. By forcibly contracting the outer tube in the circumferential direction, the outer tube is securely connected to the inner tube in the circumferential direction, and local heating and cooling effects are performed at uniform intervals in the circumferential direction, which also allows the heating device and the cooling A multi-layer pipe such as a double pipe is provided with technical means to ensure that the inner pipe and the outer pipe are uniformly tightened as a whole by moving the device in parallel in the axial direction.

<Example> Next, an example of the present invention will be described below with reference to FIGS. 1 to 8. Note that the same parts as in FIG. 9.10 will be explained using the same reference numerals.

The illustrated embodiment is a double pipe of a multi-layer pipe as a crude oil transport pipe, and in the embodiment shown in Fig. 1.2.3, a long corrosion-resistant stainless steel inner pipe 1 of a predetermined length is used. Carbon with pressure resistance! It is stacked relative to the outer tube 2 made of TILL with a predetermined ring-shaped clearance 3 therebetween, and the outer tube 2 is concentrically placed in front of the ring-shaped holder 8 at the starting end of the outer tube 2 in the traveling direction. From the side, the suppression roller 9, the heating device 4.4 of the burner, and the shower nozzle 5.5 of the cooling device immediately after it are arranged in a straight line in the axial direction, and 90 mm in the circumferential direction. Set the heating/cooling devices 10 set in positions divided into four equal parts, and each heating device 4
and each cooling device 5 are put into operation, and when the heating and cooling device 10 is moved in parallel at a predetermined speed from the starting end side to the terminal end side, the local heating due to burner heating of each heating device 4 changes to the diameter of the outer tube 2. A directional bulge effect is applied, so that the pressure roller 9
．． 9... bulges inward as shown in FIG. 2, and immediately after that, it is forcibly cooled through the shower ring of each cooling device 5, so that the spot heating and cooling portion 6 rapidly contracts in the circumferential direction. Therefore, after passing through the heating/cooling device 10, the outer tube 2 contracts in a uniform portion with respect to the inner tube 1, and the inner surface of the outer tube 2 contacts the outer surface of the inner tube 1. Since the two layers contact each other, uniform tightening is performed in the circumferential direction, and furthermore, due to the movement of the heating and cooling device 10 in the axial direction, the seven-layer double-pipe structure is tightened over the entire length from the starting end to the terminal end in the circumferential direction, and A completely axially tightened state is created.

Therefore, in this embodiment, it is not necessary for each suppression roller 9 to mechanically strongly suppress and deform the outer tube 2 inwardly, and the outer tube 2 is placed at a predetermined front portion where thermal deformation is performed by the burner of the moving heating device 4. Just press lightly.

In the embodiment shown in FIG. 4, the heating and cooling parts 6, 6, . The heating and cooling parts 6, 6... are formed in a staggered manner in the circumferential direction, so that the intervals between the heating and cooling parts 6, 6, etc. become close, and the inner tube 1 and the outer tube 2 are more securely connected. This is how it is done.

Further, in the embodiment shown in FIG. 5, the heating and cooling device 10 is set so that the heating and cooling portions 6, 6, .
This embodiment is substantially the same as the embodiment described above.

The embodiment shown in FIG. 6 has a heating/cooling section 6.6...
are arranged in a spot-like manner densely in one circumferential direction, and immediately after that, the second stage heating and cooling parts 6,6... are arranged in an arrangement manner in which the phase is shifted in the circumferential direction. This is a mode in which the inner tube 1 and the outer tube 2 are complemented in the axial direction, and the inner tube 1 and the outer tube 2 are extremely securely connected in this embodiment as well.

Further, in the embodiment shown in FIG. 7, a predetermined number of heating/cooling parts 6, 6, etc. are arranged in the circumferential direction, and the arrangement is arranged in the first and second circumferential directions in front and back in the axial direction. The heating and cooling units 6, 6... are arranged in double rows, and as shown in FIG. The aspects provided front and rear in the direction are the same, and the effects they provide are substantially the same.

It goes without saying that the embodiments of this invention are not limited to the above-mentioned embodiments. For example, the application target is not only crude oil transport pipes, but also oil country pipes and plant piping, and depending on the application, It can also be used as a building material.

In addition, multilayer pipes are not limited to double pipes, but multilayer pipes with four or five layers can also be obtained by sequentially forming an inner pipe and an outer pipe on the outside of multilayer pipes that are more than double pipes. It is something.

<Effects of the Invention> As described above, according to the present invention, it is possible to basically move simple heating means and cooling means back and forth in the axial direction without using complicated and costly means such as cladding or shrink fitting. By arranging them at regular intervals in the circumferential direction, they can be positioned later in the axial direction, or by forming them in a spiral shape and moving them axially in parallel at a predetermined speed, the outer tube can be heated in the radial direction by local heating. Immediately after engraving, forced cooling by the cooling means causes shrinkage at uniform intervals in the circumferential direction, thereby providing an excellent effect in that the inner tube and the outer tube can be tightly connected.

By providing these successive heating means and cooling means in the circumferential direction at equal intervals, the friction between the outer surface of the inner tube and the inner surface of the outer tube becomes greater than when they begin to come into contact with each other. As a result, uniform binding is distributed in the circumferential direction without causing an uneven binding state as a whole.Moreover, since heating and cooling move at a constant speed in the axial direction, it spreads over the entire multilayer pipe over time. The inner tube and the outer tube are bonded together, resulting in an excellent effect of increasing the reliability of the multilayer tube as a product.

Moreover, since the manufacturing equipment is simple, the cost is low, and the flexibility of the inner tube made of expensive stainless steel or the like is thereby increased.

[Brief explanation of the drawing]

1 to 8 are detailed explanatory diagrams of the present invention, in which FIG. 1 is a partially cutaway perspective view of one embodiment, FIG. 2 is a partially sectional view, and FIG.
The figure is a partial vertical cross-sectional view, Figures 4.5.6.7 are partial cross-sectional views of other embodiments, Figure 8 is a cross-sectional view of the same, and Figure 9 is manufacturing of a multilayer pipe based on the prior art. Partial longitudinal sectional view of the method, No. 10
The figure is a cross-sectional view of the same.

Claims (1)

[Claims] The inner tube and the outer tube are layered relative to each other through a ring-shaped clearance, and the local heating is transferred to the outer tube in the axial direction of the outer tube, and immediately after the local heating, the cooling action is applied in the axial direction to follow the local heating. In the method for manufacturing a multilayer tube, the inner tube and the outer tube are moved together so that the inner tube and the outer tube are tightly connected. 1. A method for manufacturing a bonded multilayer pipe, characterized in that: