JP3186830B2 - Insulation tube manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a heat retaining tube.

[0002]

2. Description of the Related Art Conventionally, a cylindrical pipe cover having a heat insulating layer made of a foam, which is used to insulate various kinds of pipes for temperature control or the like, is known, and a foam layer is provided on a skin sheet. It is also known that the provided plate-like laminate is fed into a mold and formed into a cylindrical shape by abutting the ends (for example, JP-A-57-61894).

[0003]

When several types of heat-retaining tubes are used for molding with one mold, an upper mold and a lower mold are used, and molded concave portions are formed on opposing surfaces of each mold. In many cases, a mold whose distance between both molds is adjustable is used. When the synthetic resin plate-like foam is molded into a cylindrical shape using this mold, the swelling of the plate-like foam narrowed radially in the gap between the upper mold and the lower mold. This causes a problem that wrinkles occur on the outer periphery.

[0004] It is an object of the present invention to solve the above-mentioned conventional problems and to provide an apparatus for manufacturing a heat retaining tube in which wrinkles do not occur on the outer periphery.

[0005]

According to a first aspect of the present invention, there is provided a metal mold having an upper mold and a lower mold, wherein molding recesses are formed on opposing surfaces of each mold, and the distance between the molds is adjustable. By inserting the synthetic resin plate-like foam into the mold, the synthetic resin plate-like foam is formed into a cylindrical shape along the molding recess in the heat retaining tube manufacturing apparatus. 3. The invention according to claim 2, wherein comb-shaped projections are provided on both sides of the molding recess along the longitudinal direction so that the upper and lower molds are engaged with each other. Is the drawing ratio of the mold (the percentage of the decrease in the area surrounded by the molding recess formed in the mold with respect to the area surrounded by the outer peripheral wall of the heat retaining tube as a product is expressed as a percentage) . The point is that the ratio is set to not more than 09% .

The material of the synthetic resin plate-like foam used in the present invention is not particularly limited, but a polyethylene plate-like foam is preferably used.

The synthetic resin plate-like foam used in the present invention may be laminated with a synthetic resin film such as a soft polyvinyl chloride film, or may be formed into a cylindrical shape and then coated. .

In the present invention, the squeezing ratio of the mold is defined as a percentage of the decrease of the area surrounded by the molding recess formed in the mold with respect to the area surrounded by the outer peripheral wall of the heat retaining tube as a product. It is a representation.

A polyethylene foam having a foaming ratio of 40 times and a thickness of 9 mm laminated with a 0.15 mm-thick soft polyvinyl chloride film is cut into a size of 100 mm × 50 mm. After fixing both ends in the direction, applying a load to the center, and measuring the limit length at which buckling wrinkles occur when returning to a no-load state, it was 102.6 mm. Therefore, it was found that the critical strain amount at which buckling wrinkles occurred on the synthetic resin film surface was 2.6%.

[0010] Therefore, for example, on the assumption that the production of thermal insulation tubing having an outer diameter of 135 (mm), when determining the aperture ratio of the mold for the critical strain amount, Ru der as follows. Area surrounded by the heat insulating tube outer peripheral wall of the outer diameter of 135m m: 143cm ² outer diameter 135m diameter corresponding to the critical strain amount 2.6% m: 3.51mm diameter reducing loss after diameter: 131.49Mm diameter reduction Area corresponding to the diameter after reduction of the amount (mold cross-sectional area) : 135.72 cm ² Drawing ratio of mold : (143-135.72 ) /143×100=5.09% From this , 5.09% It can be seen that the following is the drawing ratio of the mold to the critical strain amount.

[0011]

According to a first aspect of the present invention, there is provided an apparatus for manufacturing a heat retaining tube, wherein comb-shaped projections are provided on both sides of molding recesses formed on opposing surfaces of an upper mold and a lower mold along a length direction. Since the upper and lower dents are engaged with each other,
A large gap continuous in the length direction is not formed between the upper mold and the lower mold, and the plate-like foam formed into a cylindrical shape by the mold does not swell into the gap.

In the apparatus for manufacturing a heat retaining tube according to the second aspect, since the drawing ratio of the mold is set to 5.09% or less, no wrinkles are generated on the outer periphery of the synthetic resin plate foam.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the embodiments. Reference numeral 1 denotes a mold, which comprises an upper mold 2 and a lower mold 3, and the distance between the two is adjustable. On the lower surface of the upper die 2, a molded concave portion 21 having a rounded rectangular cross section is formed, and on the upper surface of the lower die 3, a molded concave portion 31 having a substantially circular arc cross section is formed. On both sides of the molding recesses 21 and 31 of the upper mold 2 and the lower mold 3, comb-shaped projections 22 and 32 having a height of 9 mm are formed so as to engage with each other in the longitudinal direction.

The distance between the lower surface of the upper mold 2 and the upper surface of the lower mold 3 of the mold 1 is changed from 10 mm to 17 mm in increments of 1 mm and laminated with a soft PVC film 5 having a thickness of 0.15 mm. A radiation-crosslinked polyethylene plate-like foam 6 having a foaming ratio of 40 and a thickness of 9 mm was fed into the mold 1 to produce a cylindrical heat-insulating tube 7, and the presence or absence of wrinkles on its outer periphery was visually observed. confirmed.

Table 1 summarizes the drawing ratio of the mold and the presence or absence of wrinkles in the above production test.

[Table 1] As described above, when the drawing ratio of the mold was less than 5.09% , no wrinkling was observed.

[0016]

Since the apparatus for manufacturing a heat retaining tube of the present invention is constructed as described above, it is possible to produce a heat retaining tube having no wrinkles on the outer periphery.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a heat retaining tube manufacturing apparatus of the present invention.

FIG. 2 is a partially cutaway perspective view of the mold of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 2 Upper mold 3 Lower mold 5 Synthetic resin film 6 Synthetic resin plate-like foam 7 Heat insulation tube 21 (upper mold) forming recess 22 (upper mold) comb-shaped projection 31 (lower mold) forming recess 32 Comb (lower) projection

Claims (2)

(57) [Claims] 1. A synthetic resin plate-like foam is placed in a mold comprising an upper mold and a lower mold, wherein molding recesses are formed on opposing surfaces of each mold, and the distance between both molds is adjustable. By inserting, the synthetic resin plate-like foam is formed into a tubular shape along the molding concave portion in a heat retaining tube manufacturing apparatus. A device for manufacturing a heat retaining tube, characterized in that comb-shaped protrusions are provided protruding along the upper surface and the comb-shaped protrusions of the upper die and the lower die are engaged with each other. 2. A synthetic resin plate-like foam is placed in a mold comprising an upper mold and a lower mold, in which molding recesses are formed on opposing surfaces of each mold, and the distance between the two molds is adjustable. By inserting the synthetic resin plate-like foam into the tubular shape along the molding concave portion, the synthetic resin plate-like foam is formed into a tubular shape. The apparatus for manufacturing a heat retaining tube, wherein the reduction in the area surrounded by the molding concave portion formed in the mold with respect to the reduced area is expressed as a percentage) of 5.09% or less.