JPS6169417A - Manufacture of heat insulating tube - Google Patents

Abstract

PURPOSE:To contrive to improve the productivity of heat insulating tube and at the same time enable to manufacture continuous heat insulating tube by a method wherein water main is concentrically inserted in spirally welded steel tube and rigid urethane foam is filled from a nozzle between the spirally welded steel tube and the water main and expanded. CONSTITUTION:Water main pipe 2 is concentrically inserted in a spirally welded steel tube 1. After the rear end of the water main pipe 2 is capped with a cap 5a, a nozzle 4 to pour rigid urethane foam 3 between the spirally welded steel tube 1 and the water main pipe 2 is inserted from the rear end of the water main 2 into the spirally welded steel tube 1 until the tip of the nozzle abuts against a cap 5. The rigid urethane foam 3 is poured under pressure through the nozzle 4 so as to fill and expand the rigid urethane foam 3 between the spirally welded steel tube 1 and the water main pipe 2 simultaneously with drawing-out of the nozzle in order to completely draw the nozzle 4 out of the spirally welded steel tube 1.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a heat-retaining pipe for preventing water mains from freezing in winter and for preventing water pipes from being damaged by external shocks throughout the year. It is.

(Conventional technology) Conventional thermal insulation tubes have cylinder bodies made of hard urethane foam.
The inner and outer surfaces of the cylindrical body are covered with an inner skin and an outer skin made of soft polyethylene layers, and the outside of the outer skin is covered with a protective skin made of a thin metal plate to form a heat-insulating cylinder, and the heat-insulating cylinder can be opened and closed freely. It was formed by splitting it into two vertically and clamping it tightly against the water main.

However, in the manufacturing process of the above-mentioned heat-retaining tube, the heat-retaining tube is first formed separately, and then the heat-retaining tube is sandwiched and tightly attached to the water main to manufacture the heat-retaining tube, which is time-consuming and reduces productivity. There were disadvantages in that it was not possible to improve the quality of the product, and it was not possible to manufacture long products.

(Problems to be Solved by the Invention) The problems to be solved by the present invention are to improve the productivity of heat-retaining tubes and also to be able to manufacture long heat-retaining tubes. .

(Means for solving the problems) The technical means of the present invention for solving the above problems are as follows:
A water main pipe is inserted into a spiral steel pipe on its circumferential axis, and a hard urethane foam is filled and foamed between the spiral steel pipe and the water main pipe using a nozzle.

(Example) An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the method for manufacturing the heat-retaining pipe (A) of the present invention is as follows: First, a water main pipe (2) is placed inside a spiral steel pipe (1).
Insert on the circumferential axis.

In this case, the water main (2) is inserted with a slight width protruding from both ends of the spiral steel pipe (1), and the end of the spiral steel pipe (1) is covered with a lid (5) to open the end of the spiral steel pipe (1). will be closed.

Spiral steel pipes (1) are conventionally well known, and are formed into a pipe shape by forming a soft steel band into a spiral shape and welding the joints in a non-latching state.

The soft steel strip may be a heat-treated (quenched) soft and thin stainless steel plate (0.1mya to 0.1mya to 0.1mya).
Thin aluminum plate (0.1 to 0.4 nm thick) coated with thermosetting synthetic resin paint; It is conceivable to use thin metal sheets that have excellent bending properties, and have excellent weather resistance and heat resistance, which do not suffer from discoloration, !A, etc.

The water main (2) is a conventionally well-known regular length steel pipe having a required diameter, and its inner peripheral surface is coated with a tar epoxy layer.

Next, as shown in Figure 3, M (5) is attached to the rear end of the water main (2)
After doing a), install a nozzle (4) for injecting the hard urethane foam (3) between the spiral steel pipe (1) and the water main pipe (2) from the rear end of the water main pipe (2). (1), and its tip abuts against the lid (5).

The nozzle (4) has a diameter larger than that of the water main pipe (2) and smaller than the spiral steel pipe (1).
4) Insert the water main pipe (2) into the spiral steel pipe (1).

Then, the hard urethane foam (3) is compressed and injected through the nozzle (4), and as shown in FIG.
At the same time, the hard urethane foam (3) is filled between the spiral steel pipe (1) and the water main pipe (2) and foamed, and the nozzle (4) is completely pulled out from inside the spiral steel pipe (1).

After that, as shown in FIG. 5, an M (5) is made at the rear end of the spiral steel pipe (1).

Therefore, the heat insulating tube (A>) of the present invention is manufactured through the above steps.

(Effects of the Invention) As described above, the present invention inserts a water main pipe into a spiral steel pipe on the circumferential axis, fills the space between the spiral steel pipe and the water main pipe with hard urethane foam using a nozzle, and foams it to retain heat. Since the tube is formed, it is possible to improve the productivity of the heat-retaining tube by eliminating the labor involved in the production process compared to the conventional method, and it is also possible to manufacture long heat-retaining tubes.

[Brief explanation of the drawing]

The drawings show process diagrams of the manufacturing method according to the present invention, and FIG. 1 is a partially cutaway front view of a water main, and FIG. 2 is a sectional view of the water main inserted into a spiral steel pipe. Figure 3 is a cross-sectional view of the nozzle inserted into the spiral steel pipe, Figure 4
The figure shows a cross-sectional view of hard urethane foam injected between the spiral steel pipe and the water main pipe, Figure 5 is a cross-sectional view of the hard urethane foam filled and foamed between the spiral steel pipe and the water main pipe, and Figure 6 FIG. 2 is a partially cutaway front view of the heat-retaining tube. In the figure, (A) shows a heat-retaining tube (1), a spiral steel pipe (2), a water main pipe (3), a hard urethane foam (4), and a nozzle, respectively. Patent applicant: Sapporo Sansan Co., Ltd. Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] A method of manufacturing a heat-retaining tube, which involves inserting a water main pipe into a spiral steel pipe on its circumferential axis, and filling and foaming hard urethane foam between the spiral steel pipe and the water main pipe using a nozzle.