JPS6149725A - Manufacture of double pipe - Google Patents

Abstract

PURPOSE:To obtain a long double pipe which has adhered tightly by superposing an inner plate on an outer plate, welding the vicinity of its side face, and subsequently, bending them cylindrically with the inner plate inside, and thereafter, welding both the side faces to each other. CONSTITUTION:Weld zones 3, 4 are formed by welding the vicinity of side faces 1a, 2a and 1b, 2b of an inner plate 1 and an outer plate 2 which have been superposed, respectively. Subsequently, the plates 1, 2 are bent cylindrically with the welded inner plate 1 inside, and both the side faces 1a, 2a and 1b, 2b are butt-welded to each other, by which a double pipe is formed. According to this method, a double pipe which has a desired aperture and also has adhered tightly can be obtained easily by utilizing and adding a material being on the market. Also, a long and tight double pipe can be obtained, as well.

Description

[Detailed description of the invention] <Field of industrial application> The present invention relates to a method for manufacturing a double-walled tube, and more particularly, to a method for manufacturing a double-walled tube for large diameter use as a material for flexible tubes and the like. It is.

<Prior art> Conventionally, the method for manufacturing double pipes consists of one inner plate, two
Separately make the inner W (opening 9 and the outer tube, which is made by bending the outer plate into a cylindrical shape and welding (c)), which is bent into a cylindrical shape and welded (A), and put it inside the outer tube ←. A double tube was manufactured by inserting an inner tube (b).

However, because it is difficult to form a perfect circle due to warping caused by welding, etc., there are many cases where it is not possible to insert the inner tube (b) into the outer tube halfway, and therefore the inner tube (b) cannot be inserted halfway into the outer tube).
This creates a gap between the two pipes, making it impossible for the two pipes to come into close contact with each other, and the disadvantage is that it is impossible to manufacture long double pipes.

Furthermore, as a prior art, Japanese Utility Model Application Publication No. 57-6571τ2 provides a guide roll with a shallow groove into which an inner tube fits and a deep groove into which an outer tube fits. There was no pre-welding process.

<Problems to be Solved by the Invention> In view of the above-mentioned circumstances, the present invention aims to provide a method for manufacturing a long double-walled pipe with a desired large diameter, in which the inner and outer tubes are in close contact with each other. It is something.

Means for Solving the Problems In order to bring the inner and outer tubes into close contact, the inner plate is superimposed on the outer plate, welded together, and then bent.

It is a double pipe with a large diameter and cannot be wrapped with commercially available materials.
These problems were solved by welding the inner and outer plates in advance to the desired length.

In addition, the manufacturing method of the present invention can also be used from the block folding of one plate material.
It can also be manufactured from a continuous form of coiled material. The first step is to overlap the inner plate on the hill of the outer plate, the second and 2' steps are common in that the inner and outer plates are welded, and the third step is to fold the inner plate into a cylindrical shape. , the main part of the items indispensable to the purchase, which consists of the fourth step of welding the two sides together to make a double pipe, is the main part of the items indispensable to the preparation, and the same purpose This is a combined application pursuant to Article 38, Proviso No. 1 of the Patent Law, which consists of two inventions, a block layout and a continuous invention, which achieve the following.

In the present invention, in the fourth step, the inner and outer parts 1 are welded together to form a double pipe.

However, in the 1st and 2nd steps as well, the @ surfaces of the inner and outer plates that have been overlapped in advance are welded.

Fruit Example> The attached FIG. 1 shows a method of manufacturing a double pipe from a plastic wrap, showing a first embodiment of the present invention. (1st = inner plate,
(2) is the outer panel, and Figure 1 (1) shows the inner panel (1) and the outer panel (2).
) The first step is shown superimposed on the top of the screen.

Figure 1 (2) shows the overlapped inner plate (11) and outer plate (2).
) from the front, or 1fl on the side of the outer panel (2) (2
a) (2b) G2 tangent +31 +41, which is the second step.

, FIG. 1 (31 shows a state in which the inner plate fil after welding (31+41) is placed inside and bent into a cylindrical shape, which is the third step.

This is the 4th step and the attached 2nd step is shown below.
The figure shows another embodiment of the second step of the present invention, in which 25 plates (Q inner plate t61 G71 G2) and 1 outer plate (81 (9)) and 1 plate (a) are used. Welding (10L,
An example is shown in which they are used by adding them, and in this way, a desired large-diameter item can be obtained.

Attached Figure 3 shows (jOJ) G; r inner plate;
(b) is the outer plate, 3rd ■ (1st = inner plate (1υ) is the outer plate (2
) and continuously feed it into the welding machine α3). Inside the welding machine 03), a current flows through the material through the electrode.
near the side surfaces of the inner and outer plates θ4) (15) and the desired 2
Main adjacent parallel vertical striped surfaces (16a) (16b) (17a)
(17b) seam welded (13a) (13b) (13b
) (13c) (13c) (13d). Next 3rd ■ (
Is 2) actually continuous like M3 diagram fi+?
The cutter (C1
) and cutter (C2) to form a welded side surface.

In FIG. 3, +11 to +21 are the first steps of the present invention, and the other steps are the same as those in the first embodiment. Although not shown in the drawings, if the width is wide, it may be possible to weld the longitudinal strips for reinforcement at the center. <Effects of the Invention> Commercially available materials can be used to add parts to the desired diameter. - large double pipes can be manufactured.

Double tube 7i with inner and outer tubes in close contact: can be obtained,
'It also became possible to manufacture long double tubes.

[Brief explanation of drawings]

A perspective view of an example shown in FIG. Fig. 1 (4) is a perspective view of one embodiment showing the fourth step, Fig. 2 is a front view showing another embodiment 2 of the second step, and Fig. 3 fil is a second embodiment of the present invention. Fig. 3 is a perspective view of an embodiment showing part of the 2' step of the process.
2) is a plan view of an embodiment showing the remaining part of the 2' step, and FIG. 4 is a perspective view of a conventional example. In the mouth: 11 +61 (71 (11) ... inner plate,
(1a) (1b) (2a) (2b) -side, +21
+81 (91 (b)) ... Outer plate, (31 (41H)
(15)...Welding surface near the side, (16a) (16b
) (17a) (17b) Welding surface consisting of m vertical stripes.

Claims (1)

[Claims] 1. A first step of overlapping the inner plate on the outer plate, a second step of welding near the side surfaces of the inner and outer plates, and a third step of bending the inner plate into a cylindrical shape with the inner plate inward. and a fourth step of welding both sides to each other to form a double pipe. 2. The method for manufacturing a double pipe according to claim 1, wherein the side surface of the outer plate in the second step is made longer than the side surface of the inner plate. 3. The first step is to stack the inner plate on top of the outer plate, and weld the inner and outer plates near the side surfaces and two longitudinal stripes in parallel, and then cut at the center between both longitudinal stripes to form the sides. It is characterized by comprising a 2' step, a 3rd step of bending it into a cylindrical shape with the inner plate inward, and a 4th step of welding both sides to each other to form a double tube. Method for manufacturing double tubes. 4. Claim 3, characterized in that a plurality of two vertical striped surfaces are provided in the 2' step.
2. Method for manufacturing a double pipe as described in Section 1.