JPS589737B2 - Method for manufacturing coated metal pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing coated metal pipes used for piping of water heaters, water heaters, etc.

Traditionally, water heaters were installed at a suitable location outdoors and the heated water was transported to a suitable location indoors.

Water heaters were also installed at appropriate locations indoors, and pipes were piped from there to the bathrooms, washrooms, kitchens, and other locations where they were needed.

The present invention relates to a method of manufacturing a coated metal pipe used for this piping.

Conventionally, such coated metal pipes have been produced by extruding a foamed heat insulating material 1 on the outer surface of a metal pipe 3 as shown in FIG. Extrusion-coated products are also known.

However, since such a coated metal pipe has a smooth outer surface, when it is bent during piping, it causes unsightly wrinkles in the bent portion, which reduces the commercial value.

The present invention was made in an attempt to eliminate such conventional drawbacks, and the surface of the foamed heat insulating material in the form of a plate is embossed in advance to enclose a metal pipe, and the outer periphery is then processed using an extruder. A coated metal characterized in that the skin material is extruded using a foam insulation material and at the same time suction is drawn between the foam insulation material and the skin material, the skin material is seamlessly covered with the skin material, and the skin material is blended into the embossment of the foam insulation material. This is a method for manufacturing tubes.

The metal tubes coated according to the present invention are metal tubes such as iron, lead, copper, aluminum and steel.

Examples of foamed insulation materials include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylate, polymethacrylate,
It is a foamable resin such as ethylene-vinyl acetate copolymer or ethylene-propylene copolymer.

In addition, the skin material may be a flexible synthetic resin such as polyethylene, polypropylene, acrylonitrile, vinyl chloride, vinyl acetate, polyacrylate, polymethacrylate, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, or synthetic resin. It's rubber.

Therefore, in the present invention, the foam insulation material is heated in advance and the surface is embossed. Embossing can be done by engraving on one of the two rolls, but on the surface of the metal tube. If there is an embossment, you can prevent the metal tube from slipping out by engraving it on two rolls.

Further, although the shape of the emboss is not particularly limited, experimental results show that when the skin material is adapted to the foamed heat insulating material, the skin material does not deform when the height of the convex Viramit emboss is 1 to 3 mm and the pitch is 3 to 10 mm.

(Foaming ratio: 15 times) In this way, foam insulation materials require a certain degree of strength when being embossed, and foams with a foaming ratio of 30 times or more (density 0.039/CC.)
The emboss is deformed, which is not good.

In general, the strength of foam insulation materials is that a) the embossing does not deform during the coating process on metal pipes.

b) The embossment should not be deformed when the skin material is adapted to the foam insulation embossment.

C) It must have enough strength to prevent the skin layer from folding (i.e., wrinkles) when the product is bent.

is necessary.

Further, after covering the metal pipe with the foam insulation material, the joint end may be fused or bonded with an adhesive.

Furthermore, the present invention uses an extruder to extrude the skin material on the outer periphery of the foam insulation material whose surface has been embossed, and at the same time draws suction between the foam insulation material and the skin material, creating a seamless skin material. The surface of the foamed insulation material is coated with molten skin material resin using a known extruder, such as a ram extrusion, screw extrusion, or screwless extrusion machine. This allows the embossing on the surface of the insulation material to blend in with the skin material.

At this time, the foam insulation material and the skin material are fused and bonded and cannot be separated. Furthermore, according to the present invention, since the skin material is seamlessly molded, the skin layer peels off and the foam insulation material is removed from that part. This prevents damage to the material and provides an aesthetic appearance.

In addition, even if bending is performed during piping work, the skin layer and foam insulation material will be fused and molded together, and by blending the skin layer with the foam insulation material embossing, the skin layer will also be embossed. As a result, wrinkles can be prevented from forming, and resistance to aging, such as weather resistance, can be significantly increased.

The invention will now be explained with reference to the drawings.

11 is a metal tube, and there is one or more metal tubes. When using multiple metal tubes, each one is covered with foam insulation material (foam insulation layer) 12 and the joint ends are fused or bonded with adhesive 13 Further, the outer peripheral surface thereof is covered with a foamed heat insulating material 12, and the joint ends are fused or bonded 13.

In addition, the metal pipe 1 is not covered with foam insulation material 12 separately.
A foamed heat insulating material 12 is interposed between the metal pipe 11 and the metal pipe 11, and both ends of the foamed heat insulating material 12 are bonded to the foamed heat insulating material 12 covering the metal pipe 11.
The joint ends of the two are fused or bonded 13.

The foamed heat insulating material covering the metal tube 11 is embossed in advance as shown in FIGS. 3 to 5, but its shape is not particularly limited and may be any shape.

Reference numeral 14 is a skin material (skin layer) that is extruded using an extruder and suctioned by a vacuum pump, so that there is no seam and it is molded into approximately the same shape as the embossment of the foamed heat insulating material 12.

Next, examples of the present invention will be described, but the present invention should not be limited thereto.

Example: Convex Viramit embossing (height 1
．． 7 mg, pitch 6xn), and the outer periphery of a steel pipe with an outer diameter of 10 mm was coated and bonded.

Furthermore, an ethylene-vinyl acetate copolymer resin was coated and fused to a thickness of 0.5 mm using an extruder to form a skin layer.

In the product obtained above, there was no seam in the skin layer, so there was no peeling damage to the skin, there was no deformation of the embossing, and no wrinkles were observed even after bending.

In addition, by the same method as above, the foaming ratio was 30 times (density 0.
When the foam insulation material of No. 039/CC) was used, the embossment was deformed when the skin material was adapted to the foam insulation material.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional coated metal tube, Figure 2 - A, B
, C is a sectional view of the present invention, FIG. 3 is a perspective view of another embodiment of the present invention, FIG. 4 is a sectional view taken along line X-X' in FIG. 3, and FIG. 5 is a part of one embodiment. FIG. 11...Metal pipe, 12...Foam insulation material, 13...
Adhesion or fusion, 14...Skin material.

Claims (1)

[Claims] 1. Emboss the surface of the foamed heat insulating material in advance to encapsulate the metal tube, bond the joint end with heat sealing or adhesive, and then apply a skin material to the outer periphery using an extruder. At the same time as extruding the foam, suction is drawn between the foam insulation material and the skin material.
A method for producing a coated metal pipe, characterized by covering it with a seamless skin material and blending the skin material into the embossment of the foam insulation material.