JPH05301281A - Manufacturing device of heat insulation tube - Google Patents

Abstract

PURPOSE:To obtain a heat insulation tube whose outer circumference is free from creases, by a method wherein at the time of manufacturing of the heat insulation tube by running a synthetic resin boardlike foam through a molded recessed part formed on confronting surfaces between a top force and bottom force, a space between which is adjustable, protrusions like the teeth of comb which bite with each other are projected in the longitudinal direction of both sides of the molded recessed parts of the top force and bottom force. CONSTITUTION:A space between a top force 2 and bottom force 3 is adjustable and molded recessed parts 21, 31 are formed respectively on confronting surfaces of them. Protrusions 22, 32 like the teeth of comb which bite with each other are projected on both sides of the molded recessed parts 21, 32 along alongitidinal direction. With this construction, large gaps continuing in the longitudinal direction are not generated between the top force 2 and bottom force 3 and a boardlike foam formed cylindrically is not expanded into the gap. Then it is preferable that a draw ratio of a mold is made at the most 5%.

Description

Detailed Description of the Invention

[0001]

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

[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 a pipe for various temperature adjustments, is known, and a foam layer is formed on a skin sheet. It is also known that the plate-shaped laminate provided is fed into a mold and the ends thereof are abutted against each other to form a cylindrical shape (for example, JP-A-57-61894).

[0003]

By the way, when heat-insulating tubes of several kinds of diameters are used for molding with one mold, the mold is composed of an upper mold and a lower mold, and molding recesses are formed on the surfaces of the respective molds facing each other. It is often the case that a mold in which the distance between the two molds can be adjusted is used. When a synthetic resin plate-like foam is molded into a cylindrical shape using this mold, the swelling of the plate-like foam squeezed in the radial direction in the gap between the upper mold and the lower mold. There is a problem in that wrinkles occur on the outer circumference.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide an apparatus for manufacturing a heat insulating tube in which wrinkles do not occur on the outer circumference.

[0005]

According to a first aspect of the present invention, there is provided a metal mold comprising an upper mold and a lower mold, wherein molding cavities are formed on surfaces of the respective molds facing each other, and a space between the molds can be adjusted. In a device for manufacturing a heat-insulating tube in which a synthetic resin plate-shaped foam is inserted into a mold to form the synthetic resin plate-shaped foam in a tubular shape along a molding recess, an upper mold and a lower mold are manufactured. The invention according to claim 2, wherein comb tooth-shaped projections are provided on both sides of the molding recess along the lengthwise direction so that the comb tooth-shaped projections of the upper die and the lower die engage with each other. Has a drawing ratio of about 5%
The main points are as follows.

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 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 tubular shape and then covered. .

In the present invention, the drawing ratio of the mold is a percentage of the decrease in the area surrounded by the molding concave portion formed in the mold with respect to the area surrounded by the outer peripheral wall of the heat insulating tube which is a product. It is a representation.

A polyethylene plate-like foam having a foaming ratio of 40 times and a thickness of 9 mm laminated with a soft polyvinyl chloride film having a thickness of 0.15 mm is cut into a size of 100 mm × 50 mm, and the film surface is faced up. After fixing both ends in the direction, applying a load to the center, and returning to the unloaded state, the limit length at which buckling wrinkles occur was measured and found to be 102.6 mm. Therefore, it was found that the critical strain amount at which buckling wrinkles occur on the synthetic resin film surface is 2.6%.

Therefore, for example, assuming that a heat insulating tube having an outer diameter of 135 mm is manufactured, the drawing ratio of the mold with respect to the limit strain amount is calculated as follows. Area surrounded by outer wall of 135 mm outer diameter heat insulation tube: 143 cm ² Diameter reduction amount corresponding to 2.6% limit strain amount of 135 mm outer diameter: 3.51 mm Diameter reduction amount Diameter after reduction: 131.49 mm Diameter reduction amount after reduction Area corresponding to diameter (die cross-section area): 135.72 cm ² Die drawing ratio: (143-135.72) / 143 × 100 = 5.09% From this, approximately 5% or less is the die drawing for the critical strain amount. It turns out that it is a ratio.

[0011]

According to the apparatus for manufacturing a heat insulating tube of claim 1, comb-shaped projections are provided on both sides of the molding recess formed on the surfaces of the upper mold and the lower mold that face each other, along the length direction. Since the upper and lower mold comb-shaped projections are adapted to occlude each other,
A large gap continuous in the lengthwise direction does not occur in the middle between the upper mold and the lower mold, and the plate-shaped foam molded in a tubular shape by the mold does not swell into the gap.

In the heat insulating tube manufacturing apparatus of the second aspect, since the die drawing ratio is about 5% or less, wrinkles do not occur on the outer periphery of the synthetic resin plate foam.

[0013]

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 is composed of an upper mold 2 and a lower mold 3, and the distance between them can be adjusted. On the lower surface of the upper mold 2, a molding concave portion 21 having a rounded corner is formed, and on the upper surface of the lower mold 3, a molding concave portion 31 having a substantially arc-shaped 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 tooth-shaped projections 22 and 32 having a height of 9 mm are formed so as to occlude each other along the length direction.

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

Table 1 collectively shows the drawing ratio of the mold and the presence or absence of wrinkles in the above manufacturing test.

[Table 1] As described above, wrinkles were not observed when the die drawing ratio was less than 5.09%.

[0016]

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

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of an apparatus for producing a heat insulating tube of the present invention.

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

[Explanation of symbols]

 1 Mold 2 Upper Mold 3 Lower Mold 5 Synthetic Resin Film 6 Synthetic Resin Plate Foam 7 Heat-Retaining Tube 21 (Upper Mold) Molded Recess 22 (Upper Mold) Comb-Shaped Protrusion 31 (Lower Mold) Molded Recess 32 (Lower mold) comb teeth

Claims (2)

[Claims] 1. A synthetic resin plate foam is placed in a mold, which comprises an upper mold and a lower mold, and in which molding recesses are formed on the surfaces of the respective molds facing each other, and the distance between the two molds can be adjusted. In a device for manufacturing a heat insulating tube in which the synthetic resin plate-shaped foam is formed into a tubular shape along the molding recess by inserting, in both sides of the molding recess of the upper mold and the lower mold, in the length direction. An apparatus for manufacturing a heat-retaining tube, characterized in that comb-shaped projections are provided along the projections, and the upper and lower comb-shaped projections are intermeshed with each other. 2. A synthetic resin plate foam is placed in a mold having upper and lower molds, in which molding recesses are formed on the surfaces of the respective molds facing each other, and the distance between the two molds can be adjusted. In a device for manufacturing a heat retaining tube in which the synthetic resin plate-shaped foamed body is molded into a tubular shape along the molding recess by inserting the heat insulating tube, the mold has a drawing ratio of about 5% or less. Manufacturing equipment.