JPH0261383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite tube in which an inner and outer tube are bonded together through a foam layer, such as a composite tube in which a synthetic resin lining is applied to a metal tube through a foam layer.

As a manufacturing method of the above-mentioned composite pipe, the applicant of the present application has applied a foaming adhesive to either one or both of the inner surface of the outer tube or the outer surface of the inner tube, as described in JP-A-57-157718, The inner tube is inserted into the inner tube, and while both tubes are rotated in the circumferential direction, the foamable adhesive is heated by moving and showering hot water along the tube, and the foamable adhesive is foamed and hardened between the two tubes. However, in this method, heating is performed by moving a hot water shower in the axial direction of the tube while it is rotating in a fixed position, so the foaming curing process of the foaming adhesive is done in batches, and the adhesive This foaming and curing process takes a long time compared to the process of coating the tube and the process of inserting the foam, which is a factor in the slow production speed of this manufacturing apparatus.

In order to increase the operating efficiency of the coating and insertion processes, it is possible to install multiple lines of foam curing processes, but this would require transporting long tubes in a manner that distributes them to each line, which would require complicated transportation. This method has disadvantages in that it requires a large amount of equipment and a large space for installing the equipment.

The present invention solves the above-mentioned drawbacks of the conventional composite pipe manufacturing method by heating the pipe by passing it under a bifurcated hot water shower while rotating the pipe.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a front view showing an example of the manufacturing process of a double pipe with a foamable adhesive layer interposed therebetween. In the present invention, the double tube may be one in which a foaming adhesive is applied to one or both of the inner surface of the outer tube or the outer surface of the inner tube, and the double tube is fitted into the tube. In the example shown, a foam adhesive is applied to the inner surface of the outer tube and the inner tube is inserted into it.The outer tube is a metal tube such as a steel tube, and the inner tube is a lined tube such as a synthetic resin tube. This is a suitable example for manufacturing composite pipes using synthetic resin lining on the inner surface.

Reference numeral 1 denotes an outer pipe such as a steel pipe, which is placed on rolls 2, 2, ... provided on a pedestal, and rolls 2, 2, ...
It is made to rotate in the circumferential direction by rotating...

Reference numeral 3 denotes a foam adhesive applicator, in which a foam adhesive introduction pipe 33 is fixed onto a mover 32 fixed on a rotating belt 31 and a mover 32' which is movable within the outer tube 1. A nozzle 34 is provided at the tip of the introduction tube 33, and when the rotary belt 31 is rotated, the nozzle 34 moves from one end of the outer tube 1 to the other end, so that the foaming adhesive can be sprayed onto the inner peripheral surface of the outer tube 1. There is.

Reference numeral 4 designates an inner tube such as a hard vinyl chloride resin tube. A plurality of protrusions 41 are provided in the axial direction of the outer circumferential surface of the inner tube 4 to partially fill the gap with the outer tube 1, and the inner tube 4 is placed on the rotating belt 5. When 5 is rotated, it can be inserted into the outer tube 1, and is positioned coaxially with the outer tube 1 by the protrusion 41 so that it can be inserted. In the above device, the outer tube 1 is rotated by rotating the rolls 2, 2, .
While rotating the tube in the circumferential direction, the nozzle 34 is introduced into the outer tube 1 and moved from one end to the other end to spray coat the foam adhesive on the inner peripheral surface.

After coating, a nozzle 34 is taken out from inside the outer tube 1, a rotary belt 5 is rotated, and an inner tube 4 whose outer surface is not coated with adhesive is inserted into the outer tube 1 to form a double tube 6.

After inserting the inner tube 4 into the outer tube 1, the double tube 6 is inserted 50 times/
It is preferable to rotate for 1 to 5 minutes at a rotational speed of 1 to 200 times/minute to ensure uniform dispersion of the adhesive, and then proceed to the heating step.

The adhesive can be applied by any method such as spraying or brushing, but the important thing is that it is applied evenly to the surface to be applied, and applying while rotating the tube will ensure an even application. suitable.

FIGS. 2 and 3 show an example of a heating process for the double pipe 6. FIG. In the figure, 7 is a hot water receiving tank, 8 is a hot water shower head, and 9 is a rotating pipe transfer device.

The pipe rotation transfer device 9 rotates the double pipe in the previous process around its axis and transfers it in a direction substantially perpendicular to the pipe axis. A conveyor 91 is provided, and a pair of tube receiving rollers 92 are provided on the conveyor 91 at equal intervals, so that when the conveyor 91 rotates, the tube receiving rollers 92 rotate. The double tube 6 is placed on a pair of tube receiving rollers 92 and rotates as the rollers rotate.

The hot water shower head 8 is bifurcated and is installed above the rotary transfer device 9. The shower head 8 is located approximately at the center of the conveyor 91 at the front in the direction of movement of the conveyor 91, and has a V-shape or a Y-shape that branches into two along the direction of movement of the conveyor 91. The shower head 8 may be a pipe provided with a spout or spout slit, or a nozzle attached thereto.

The hot water shower preferably has a Y-shape with a portion 81 extending in the direction of movement of the conveyor 91 so that the substantially central portion of the double pipe 6 can be sufficiently heated. In addition, the angle at which the two branches diverge is determined by the rotary transfer device 9.
It is determined in relation to the rotation speed of. When increasing this angle, the transfer speed of the double pipe can be slowed down, but as the angle increases, the length of the double pipe that is exposed to the hot water shower at once becomes longer, and the double pipe is gradually moved from the center. It is preferable to set the angle to 90° or less, since heating cannot be carried out toward the ends.

To heat the double tube using the above device and foam and harden the foamable adhesive layer interposed between the tubes,
First, the double tube obtained through the adhesive application process and insertion process is transferred onto the inclined pedestal 71. This double pipe 6 rolls on an inclined pedestal 71 and is placed on a pair of pipe receiving rollers 92 of a conveyor 91, and as the double pipe 6 rotates in the circumferential direction due to the rotation of the pipe receiving roller 92, the conveyor It is transferred by the rotation of 91.

Hot water shower is applied to the transfer path of this double pipe from a hot water shower head 8 branched into two at the top. As it moves, it branches into two branches, and hot water is showered toward both ends. The foamable adhesive layer interposed between the double tubes 6 is heated through the outer tube 1 by the hot water shower and foams. By adjusting the rotational speed of the conveyor 91 to the angle of branching of the hot water shower head 8, the foam adhesive layer is applied to the double tube 6.
If the foam is adjusted so that it gradually foams and hardens from the center toward both ends, the foam hardens without trapping air in the middle of the tube, and a foam layer is formed between the inner and outer tubes, bonding the two tubes together. Can be integrated.

The method for manufacturing a composite pipe of the present invention is configured as described above, and the double pipe is rotated around the pipe axis and transferred in a direction substantially perpendicular to the pipe axis, and a hot water shower branched into two from above the double pipe is transferred. This allows continuous heating and foaming curing of the foamable adhesive, and allows the line speed of the entire process to be freely adjusted in accordance with the speed of the previous process.

Furthermore, since the foamable adhesive layer is foamed and cured from the center of the tube toward both ends, there is no air remaining between the inner and outer tubes, and the foaming and curing process can be shortened.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of the manufacturing process of a double pipe with a foamable adhesive layer used in the present invention;
FIG. 2 is a plan view showing an example of an apparatus for implementing the present invention, and FIG. 3 is a front view of FIG. 2. 1: Outer tube, 2: Roll, 3: Foaming adhesive applicator, 4: Outer tube, 6: Double tube, 7: Hot water tank,
8: hot water shower head, 9: pipe rotation transfer device, 91: conveyor, 92: pair of pipe receiving rollers.

Claims (1)

[Claims] 1. A double tube with a foam adhesive applied to one or both of the inner surface of the outer tube or the outer surface of the inner tube and inserted is rotated around the tube axis and transferred in a direction substantially perpendicular to the tube axis. At the same time, the double pipe transfer path is heated by showering it with a shower of hot water that branches into two branches from the center in the direction of transfer, thereby foaming the foamable adhesive interposed between the inner and outer pipes. A method for manufacturing a composite pipe, characterized by hardening it.