JPH0752181A - Heat retaining cover for piping and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a heat retaining cover for piping which can be processed easily, can be applied to various shapes of pipe, can be manufactured easily by integral molding with the same material, and a method for manufacturing it. CONSTITUTION:In a manufacturing method of a heat retaining cover A for piping whose inside shape conforms with an outline of a pipeline P whose heat is to be retained, an expansion molding mold wherein the heat retaining cover A has a two-piece structure of two bases 1, 1 and cavities relating to the pair of bases 1, 1 are also provided is used. The expansion molding mold is filled with pre-expanding beads of polyolefin resin. Thereafter, the inside of the expansion molding mold in a clamped state is heated. Then, molding expansion of the bases 1 is done by fusion among the pre-expanding beads. On the other hand, a slide plate arranged on a core mold is lowered and the fusing layer of the pre-expanding beads arranged between the cavities relating to the bases 1, 1 is compressed into a thin skin, so that a hinge 2 to be connected to both bases is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating cover for piping which is easy to construct and can be easily manufactured as an integrally molded product of the same material, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A heat insulating cover for piping is attached to air conditioning piping of various factories and homes in order to reduce heat transfer caused by a temperature difference between a fluid temperature inside the piping and an outside air temperature. Conventionally, the following types of heat insulating covers have been mainly used. First, as shown in FIG. 10, the heat insulation cover C is simply divided into two (prior art 1). Alternatively, the heat insulation cover C is manufactured by vacuum forming an extruded foam sheet as shown in FIG. 11 (prior art 2). In addition, as shown in FIG.
There is also one in which a resin sheet 92 is adhesively fixed (prior art 3).

[0003]

However, any of the conventional heat insulating covers C has a problem. In the prior art 1,
Since the heat-retaining cover C is separated and is a separate body, not only the number of parts increases but also construction on site is difficult. In the heat insulating cover C according to the related art 2, since the sheet-shaped foam is vacuum-formed, the thickness of the bent portion 93 is restricted, and a thick material cannot be formed. Of these types, those manufactured by the continuous extrusion foaming method are limited to those for straight pipes in terms of the manufacturing method. In addition, the heat insulating cover C of the related art 3 is an assay product in which a separate resin sheet 92 is combined, so that the manufacturing cost is high. Further, when any of the above heat insulating covers C is heat-insulated, it is necessary to fix the heat insulating cover C with a double-sided tape or to cover the pipe with the heat insulating cover and then wind the tape with wire or wire. . At this time, it was difficult to wind the tape while covering the pipe with the heat insulating cover C and fitting the mating surface exactly with one hand. As a result, the work efficiency is low, and in addition, a defect such as a misalignment of the mating surface is often caused.

The present invention solves the above problems and provides a heat insulating cover for piping and a method of manufacturing the same which is easy to construct and can be applied to various piping shapes and can be easily manufactured by integral molding of the same material. The purpose is to provide.

[0005]

The heat insulating cover for piping according to the first aspect of the present invention is a heat insulating cover for piping which is obtained by filling pre-expanded beads of polyolefin resin in a foam molding die and molding and foaming the heat insulating cover. A base part where the main body of the cover is divided into two,
It is characterized in that the pre-expanded beads are formed into a thin skin by pressing the heated fusion-bonding layer, and the hinge portion for joining the side edges of the pair of base portions is integrally formed. The heat insulation cover for pipes according to the second aspect of the present invention is the heat insulation cover for pipes according to the first aspect of the present invention, in which a step-like fitting claw is formed on the mating surface of the base, and a dovetail groove into which the fitting claw is inserted is provided on the other base. The feature is that it is provided.

According to a third aspect of the present invention, there is provided a method for producing a heat insulating cover for a pipe, wherein the heat insulating cover has a base divided into two parts. Using a foam molding die in which cavities related to the base are arranged side by side, after pre-expanding beads of a polyolefin resin are filled in this foam molding die, then the inside of the foam molding die in the mold closed state is closed. While heating and performing molding and foaming of the base portion by fusing the pre-expanded beads together, the slide plate provided in the core mold is lowered to form a fusion layer of the pre-expanded beads arranged between the cavities of the pair of base parts. It is characterized in that a hinge portion joined to both base portions is provided by compressing in a thin skin shape.

Here, the "polyolefin resin" means
A resinous substance produced by the polymerization of olefins, which is a synthetic resin that has grown into a polymer such as polyethylene, polypropylene, or polybutene by a polymerization reaction. The "pre-expanded beads" are those obtained by pre-expanding a granular resin impregnated with a foaming gas in a pre-expanding machine at a predetermined ratio.

[0008]

According to the heat insulating cover for piping and the method of manufacturing the same according to the present invention, since the hinge portions join the base portions of the heat insulating cover main body which are divided into two parts, the mating surfaces can be easily matched when the pipe is covered with a predetermined pipe. To do. And, since the hinge portion is made by thinning the fusion layer of the foam beads of the polyolefin-based resin, it has flexibility as well as withstands bending strength, and helps facilitate heat insulation work. Become. In addition, when the stepped fitting claw is formed on the mating surface of the base, the pipe is covered with such a heat insulating cover to keep the fitted state of the bases, which facilitates the construction further. In addition, since the fitting claw has a stepped mating surface, it has a function of blocking air passing through the heat insulating cover. Furthermore, since the base portion and the hinge portion are integrally molded using pre-expanded beads, they can be easily manufactured.

[0009]

EXAMPLES The present invention will be described in detail below based on examples. (1) Configuration of Pipe Heat Insulation Cover Embodiment 1 FIGS. 1 to 4 show an embodiment of the pipe heat insulation cover A according to the present invention. It is for keeping the temperature around the branch pipe warm.
FIG. 1 is an overall perspective view of a heat insulating cover for piping, FIG. 2 is a perspective view showing a state of being attached to piping, and FIG. 3 is an enlarged view near a fitting claw.
FIG. 4 is a sectional view taken along line XX of FIG.

The heat insulating cover A for piping is composed of bases 1 and 1 in which the main body of the heat insulating cover is divided into two parts, and a hinge portion 2 connecting the bases 1 and 1. The base portion 1 and the hinge portion 2 are integrally molded by filling a predetermined amount of pre-foamed beads into the foam molding die 3 (described later). As the pre-expanded beads, there were used those obtained by primary-expanding granular polypropylene impregnated with foaming gas with a pre-expanding machine at a magnification of 45 times (trade name "Kaneka Eperan PP4, manufactured by Kaneka Kagaku Kogyo Co., Ltd.").
5 ”).

The base portion 1 has an inner surface shape adapted to the outer shape of the branch pipe which is the heat-insulated pipe P, and has a required heat-retaining thickness t. By winding a pair of halved bases 1 and 1 around a branch pipe, the branch pipe has a structure in which it is wrapped with a stop ring (FIG. 2). A fitting claw 12 as shown in FIG. 1 is formed on the mating surface 11 between the bases 1, 1. And the fitting claw 1
The mating surface 11 of the base 1 of the other side having no 2 has a dovetail groove 13 into which the fitting claw 12 fits. The fitting claw 12 is shown in FIG.
As described above, about half of the thickness t is raised so that the mating surface 11 has a stepped shape. By configuring the fitting claws 12 in this way, the fitting claws 12 not only serve as stoppers,
The outflow path of the air that crosses the heat insulating cover A is lengthened to prevent the air from entering and exiting. Although the length of the fitting claw 12 is limited by the shape of the heat insulating cover A in this embodiment,
Preferably occupies a large area as long as possible.
This is because the sealing portion by the fitting claw 12 is increased and the energy loss diffused from the fluid in the pipe to the outside of the system can be reduced.

The fitting claw 12 has a protruding portion 121 whose tip projects outward in the center direction of the pipe and the longitudinal direction of the pipe. The overhang 121 is 2 mm from the root
I'm on a business trip. This is because the hook function is exerted. Here, the fitting claw 12 having the overhanging portion 121 is made of expanded polypropylene resin and has elasticity and withstands repeated use, so that the hooking function is maintained for a long time. It does not have elasticity like styrofoam, and even if the fitting claw 12 is made, it does not break immediately.

The hinge part 2 is a thin film which is integrally formed with the base part 1 and joins the side edges of the pair of base parts 1 and 1. This hinge part 2 is finished by pressing and pressing after the pre-expanded beads arranged between the base parts 1 and 1 are heated and foam-melted and confirmed to be a fused layer. Base 1,
This is for allowing the 1s to rotate with respect to each other and to have a hinge function. Specifically, the molding foam thickness is 5 mm
Is compressed to about 1 mm. here,
Bubbles have come out and are flattened. Like this,
In addition to the flexibility of polypropylene resin, its thinness adds flexibility to bending and further improves flexibility. Furthermore, since it is made of polypropylene resin, it is tough despite its thinness and can withstand repeated bending.
The hinge portion 2 has a length of about 20 mm and a width of about 4 mm.

Embodiment 2 This embodiment is a heat insulation cover A for straight pipes (FIGS. 5 and 6). It is made by integral molding. Base 1,
When the mating surfaces 11 are aligned with each other, 1 forms an inner diameter for accommodating the heat-insulated pipe P. The hinge portion 2 is a thin film having the same structure as that of the first embodiment, but in this embodiment, the hinge portion 2 is arranged over the entire side edge of the base portion 1 (FIG. 6). This is because air can be completely blocked from entering and exiting through the mating surface 11. However, the hinge portion 2 may be intermittently provided as shown in FIG. Further, the fitting claw 12 is provided on the thin band band 14. The band 14 also has the same structure as the hinge 2. When the mating surfaces 11 of the bases 1 and 1 are aligned with each other and the band strip 14 is wound, the fitting claws 12 are fitted into the dovetail grooves 13. Other configurations are the same as those in the first embodiment.

(2) Method of manufacturing heat insulating cover for piping The method of manufacturing the heat insulating cover for piping according to the second embodiment will be described. The foam molding die 3 comprises a cavity die 31 and a core die 32, each having a steam chamber 5 in which a steam pipe 4 is laid (FIG. 8). The foam mold 3 has a heat insulation cover A
The cavities associated with the bases 1 and 1 that are half-divided are arranged side by side.
Cavity is formed. Reference numeral 6 denotes a slide plate provided on the core die 32, which is vertically moved by a slide cylinder 7. As the pre-expanded beads, which are the raw material for forming and expanding, those which have been primary expanded 45 times as described above are used.

In the method of manufacturing the heat insulating cover A for piping, the following steps are repeated for each cycle. First, the core mold 32 is lowered and brought close to the cavity mold 31 to bring it into a state close to mold closing. Then, air is blown into the cavity. This is for removing water drops on the surface of the mold product. Next, the valve of the raw material filling machine (not shown) is opened, and the pre-expanded beads are filled in the cavity. After confirming that a predetermined amount of pre-expanded beads are filled in the mold, the mold closing is completed. After this, the heating step of flowing the heating steam from the outlet 41 of the steam pipe 4 is started.

Here, the cavity die 31 and the core die 32 are provided with a large number of vapor holes (not shown) having slits. Therefore, the steam chamber 5 is not only heated, but the heated steam directly enters between the pre-expanded beads through these steam holes. Then, the pre-expanded beads are heated while expelling the air between the pre-expanded beads. By this operation, the pre-expanded beads become soft and change into a fused layer in which the pre-expanded beads are bonded to each other while expanding. Thus, a cavity-shaped molded product is completed. The expansion ratio of such molding foam alone is about 1.1 to 1.8.
The density of the molded product depends on the specifications of the heating steam, but the heating steam used has a pressure of 2 kg / cm ² and a temperature of about 140 ° C.

Subsequently, the slide cylinder 7 is operated while the pre-expanded beads are foam-bonded in the cavity. The slide plate 7 is lowered by the operation of the slide cylinder 7, and the thin skin-like hinge portion 2 and band band 14 are built by compressing the fusion layer in the foam fusion state directly below the slide plate 6. When the slide plate 6 presses the fusion layer, the foaming gas in the hinge portion 2 is expelled, and the hinge portion 2 and the band strip 14 are pressed.
Is a transparent thin film. After that, the heating steam is stopped, and cooling and cooling are performed. In this way, the molding and foaming is completed, and the process proceeds to the next mold opening. FIG. 8 is an explanatory cross-sectional view of the mold open state. Finally, the eject pin 8 projects, and the desired heat insulating cover A for piping is taken out. In the base portion 1 of the heat insulating cover A, a highly foamed body having a size of 50 to 80 times is obtained.

FIG. 9 shows a foam molding die 3 of another specification. According to the foaming mold 3, the hinge part 2 is lowered from the mating surface 11 by one step, so that the heat insulating cover A in which the pressing force is easily generated on the mating surface 11 can be manufactured. Since the hinge portion 2 is separated from the mating surface 11 of the heat insulating cover A, the workability of mounting on the site is improved.

(5) Effects of the Embodiments According to the heat insulating cover for piping and the method for manufacturing the same in the above-described aspect, since the hinge portion 2 is joined to the side edges of the bases 1 and 1, the heat insulating pipe P is The mating surfaces 11 coincided with each other only by covering them, which facilitated the heat insulation work. The hinge portion 2 was thin and flexible, excellent as a hinge member, and durable enough to be used repeatedly. Once fitted into the dovetail groove 13, the fitting claw 12 is unlikely to come off, and the heat insulating cover A maintains a cylindrical body.
I was able to proceed with the construction easily. And the hinge part 2
Since it was integrated with the base 1 to prevent lateral displacement, the finish was also good. In addition, the bases 1 and 1 and the hinge 2
Since it is integrally molded, handling and inventory management were easy.

Further, since the base portion 1 and the hinge portion 2 are made by integral molding with the foaming mold 3, the manufacturing process is simplified, an inexpensive product is provided, and various pipe shapes can be dealt with. Moreover, since the pre-expanded beads are used, it is possible to obtain a high foam having a heat retaining effect unlike the one-step foaming. Furthermore, when the fitting claw 12 that makes the mating surface 11 of the base 1 step-like is elongated in the direction of the heat-insulated pipe, the gap between the mating surfaces 11 can be closed, so that the gap between the mating surfaces 11 and 11 can be closed. It was possible to improve the heat retention by blocking the air entering and exiting from the outside. In addition, in the heat insulating cover A in which the hinge portion 2 is lowered from the mating surface 11 by one step, the mating surface 11 can be easily joined to the mating surface 1.
It became easier to apply a pressing force to 1.

The present invention is not limited to those shown in the above embodiments, but can be variously modified within the scope of the present invention depending on the purpose and application. For example, the polyolefin resin used for the pre-expanded beads may be a resin mainly composed of polyethylene, polypropylene or the like, which contains at least 50% or more thereof. Pigments, antistatic agents, heat stabilizers, etc. are added as needed. As the foam molding die 3, a horizontal shape can be adopted instead of a vertical shape.

[0023]

As described above, the heat insulating cover for piping and the method for manufacturing the same according to the present invention are easy to install, can be applied to various pipe shapes, and can be manufactured by integral molding, so that the manufacturing process is simplified and the product is inexpensive. It is possible to provide excellent effects.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a heat insulating cover for piping according to a first embodiment.

FIG. 2 is a perspective view showing a state in which the heat insulation cover according to FIG. 1 is attached to a pipe.

FIG. 3 is an enlarged view of the vicinity of a fitting claw.

4 is a sectional view taken along line XX of FIG.

FIG. 5 is a transverse cross-sectional view of a heat insulating cover for piping according to a second embodiment.

FIG. 6 is a perspective view of FIG.

FIG. 7 is a perspective view of a heat insulating cover for piping having a specification different from that of FIG.

8 is an explanatory cross-sectional view showing an apparatus for manufacturing a heat insulating cover for piping according to FIG.

FIG. 9 is an explanatory cross-sectional view showing an apparatus for manufacturing a heat insulating cover for piping having a specification different from that of FIG.

FIG. 10 is a perspective view of a heat insulating cover of Prior Art 1.

FIG. 11 is a perspective view of a heat insulating cover of Prior Art 2.

FIG. 12 is a perspective view of a heat insulating cover of Prior Art 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 11 Mating surface 12 Fitting claw 13 Dovetail groove 2 Hinge part 3 Foaming mold 32 Core type 6 Sliding plate A Pipe heat retaining cover

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29L 31:00

Claims (3)

[Claims] 1. A heat insulating cover for piping, which is obtained by filling pre-expanded beads of a polyolefin resin into a foaming mold and molding and foaming the base, wherein the body of the heat insulating cover is divided into two parts. A pipe characterized in that the pre-expanded beads press the heated fusion-bonding layer to form a thin skin, and a hinge part (2) for joining side edges of the pair of base parts is integrally formed. Insulation cover for. 2. The heat insulating cover for piping according to claim 1, wherein a stepped fitting claw is formed on a mating surface of the base, and a dovetail groove fitted into the fitting claw is provided on the other base. 3. A method of manufacturing a heat insulating cover for a pipe, the inner shape of which conforms to the outer shape of a heat insulating pipe, wherein the heat insulating cover has a base divided into two parts, and foam molding in which cavities related to the pair of bases are arranged in parallel. After using the mold to fill the pre-expanded beads of the polyolefin resin into the foam-molded mold, the mold-closed foam-molded mold is heated to fuse the pre-foamed beads together. While the base is molded and foamed by, the slide plate provided in the core mold is lowered, and the fusion layer of the pre-expanded beads arranged between the cavities of the pair of bases is compressed into a thin skin to form both bases. A method for manufacturing a heat insulating cover for piping, characterized in that a hinge part to be joined to is provided.