JPH11257545A - Heat insulating pipe and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat insulating pipe whose inner pipe is made out of a hard synthetic resin, which is easy to manufacture, excellent in quality, and has a stable structure preventing heat insulating material from being protruded or drawn out from cut-ends. SOLUTION: An inner pipe 1 is formed up by letting belt shaped hard synthetic resin material 1' in a semi-fused state be wound up in a spiral form, and a heat insulating layer 2 is formed up by letting belt shaped heat insulating material 2' made out of a foamed polyethylene resin which is non-adhesive or hardly bonded to the inner pipe 1 made out of a hard synthetic resin, be similarly wound up in a spiral form over the inner pipe 1, and concurrently, the outer and inner end parts themselves wound up in advance at the joining surface of the belt shaped heat insulating portion and the belt shaped heat insulating portion wound up later on, are mutually fused so as to be integrally bonded with each other 4 and 5, and an outer pipe 3 is formed up by letting belt shaped material 3' made out of a soft synthetic resin by wound up furthermore over the heat insulating material layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating pipe having a straight inner pipe made of a hard synthetic resin such as a heat insulating drain pipe for air conditioning equipment and the like, and to a method of manufacturing this heat insulating pipe.

[0002]

2. Description of the Related Art Conventionally, as such a straight synthetic resin heat insulating pipe, a cylindrical heat insulating material made of foamed polyethylene resin is coated on the outer peripheral surface of a hard vinyl chloride resin inner pipe obtained by extrusion molding. A heat-insulating pipe is widely known in which the heat-insulating layer is formed by fitting the heat-insulating layer, and the outer peripheral surface of the heat-insulating layer is covered with an outer tube made of a soft vinyl chloride resin.

[0003]

However, in the heat-insulating pipe having such a structure, the inner pipe made of a hard vinyl chloride resin obtained by extrusion molding is inserted into a cylindrical heat-insulating material, or a hard vinyl chloride resin is used. A pair of semi-cylindrical heat insulators are put on the resin inner tube in a cylindrical shape, joined together and adhered together, and then a sheet of soft vinyl chloride resin is formed on the heat insulator into a tubular shape. Since it is manufactured by coating while molding, not only is the manufacturing complicated and time-consuming, but also when the heat-insulating material is fitted on the inner pipe made of a hard vinyl chloride resin, the cylindrical heat-insulating material is used. However, there is a problem in that a portion that expands or contracts in the length direction occurs, and it is difficult to make all the heat insulating pipes substantially uniform.

Further, the vinyl chloride resin forming the inner tube and the foamed polyethylene resin forming the heat insulating layer have poor adhesion and are difficult to be integrated by an adhesive or fusion. If the inner pipe made of the rigid vinyl chloride formed in the above-mentioned cylindrical shape is covered with a heat insulating material of the same cylindrical shape, a gap is formed between the inner pipe and the heat insulating material, and the hard vinyl chloride resin is removed from the heat insulating material of the cylindrical shape. There is a possibility that the inner tube made of steel may easily come off.

The problem with this escape is that if a heat insulating layer made of a band-like foamed polyethylene resin is spirally wound on a cylindrical hard vinyl chloride inner tube to form a heat insulating layer, the heat generated by the winding causes a tightening force. However, in a heat-insulating pipe having a heat-insulating layer formed by helically winding such a band-shaped material, when the heat-insulating material is cut into a pipe of a desired length, the heat-insulating material easily jumps out of the cut end of the pipe and the heat-insulating layer with respect to the inner and outer tubes. However, there is a problem that distortion occurs due to delusion in the circumferential direction or the length direction, the form becomes unstable, and the commercial value decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an insulated pipe made of a rigid synthetic resin whose inner pipe is easy to manufacture and whose quality and shape are stable. It is to provide a manufacturing method.

[0007]

In order to achieve the above object, the heat insulating pipe of the present invention is formed by spirally winding a heat insulating material made of a foamed resin around an outer peripheral surface of a cylindrical hard synthetic resin inner tube. In a heat insulating pipe of a straight pipe in which a heat insulating layer is formed and an outer peripheral surface of the heat insulating layer is covered with an outer pipe made of a soft synthetic resin, the inner pipe made of the hard synthetic resin is a strip material of a hard synthetic resin in a semi-molten state. Has a structure formed by spiral winding.

[0008] In the heat insulating pipe configured as described above,
According to a second aspect of the present invention, the heat insulating material wound on the inner tube made of the hard synthetic resin is made of an olefin foam resin such as a foamed polyethylene resin, and the heat insulating material portion wound first and the heat insulating material wound next. At least a part of the joint surface with the material portion is bonded to each other.

According to a third aspect of the present invention, there is provided the method for manufacturing a heat-insulating pipe, wherein the semi-molten hard synthetic resin strip is wound on a forming rotary shaft first by the following process. By successively spirally winding the band-shaped material portion so as to have an overlapping width of 1/2 or more, at least 3 in the thickness direction.
A layer of more than one layer of the strip material is shifted in the length direction and overlaps to form a rigid synthetic resin inner tube with a certain thickness that is integrated and semi-fused on this synthetic resin inner tube. A helical wrapping of a zonal cross-section made of an olefin-based foamed resin in a state is wound spirally while at least a part of the front surface of the next wrapped band is fused to the back of the previously wrapped band. To form a heat insulating layer, and further, a semi-molten soft synthetic resin band having a certain width is wound on the heat insulating layer next to the rear end edge of the previously wound band. It is characterized in that a flexible synthetic resin outer tube is formed by spirally winding the front end portion of the band-shaped material portion while fusing it.

[0010]

A hard synthetic resin inner tube is formed by spirally winding a semi-molten hard synthetic resin strip on a molding rotary shaft, and a half of the inner tube is formed on the inner tube when the inner tube is formed. A heat insulating layer is formed by spirally winding a band-shaped material having a rectangular cross section made of a molten olefin-based foamed resin, and at the same time, a semi-molten soft synthetic resin band is spirally wound on the heat insulating layer. Thereby, a soft synthetic resin outer tube is formed. Therefore, it is possible to efficiently manufacture a homogeneous heat insulating pipe having a rigid hard synthetic resin inner pipe. At this time, a thin material as a semi-molten hard synthetic resin band material, which is thinner and wider than the above-mentioned band-shaped heat insulating material or soft synthetic resin band material, is applied to the band-shaped material portion wound first on the rotary shaft for molding. On the other hand, the inner and outer peripheral surfaces of a certain thickness are formed by overlapping several layers of hard synthetic resin by successively spirally winding the next strip so that the next strip has an overlap width of 1/2 or more. A hard rigid resin inner tube can be obtained.

Further, since the heat insulating layer is formed by spirally winding the band heat insulating material on the hard synthetic resin inner tube, the band heat insulating material is firmly fixed to the hard synthetic resin inner tube by winding. Even if the belt-shaped heat insulating material is made of an olefin-based foamed resin such as a foamed polyethylene resin that is non-adhesive or difficult to adhere to a hard synthetic resin such as a vinyl chloride resin, it is wound into a cylindrical shape. There is no danger that the inner tube made of hard synthetic resin will fall out of the heat insulation layer.

Further, when the heat-insulating pipe of the present invention is cut into fixed lengths, or when the heat-insulating pipe is cut to a fixed size and attached to equipment such as an air conditioner, the heat insulating material is wound spirally. Since the part of the joint surface between the previously wound heat insulating material part and the next wound heat insulating material part is integrally bonded, it is possible to prevent the heat insulating material from jumping out of the cut end of the pipe. At the same time, the heat insulating material is partially prevented from being perturbed in the length direction and the circumferential direction, and maintains a stable form.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a specific embodiment of the present invention will be described. FIG. 1 is a simplified side view in which a part of a heat insulating pipe formed in a rigid straight pipe is sectioned.
Reference numeral 1 denotes an inner tube having a constant thickness made of a hard synthetic resin such as a hard vinyl chloride resin or an ABS resin, and formed by spirally winding a semi-molten hard synthetic resin strip on a rotational molding shaft. The inner and outer peripheral surfaces are formed as flat surfaces having the same diameter over the entire length. Note that it is preferable to use an ABS resin because the vinyl chloride resin may generate dioxin during incineration. On the outer peripheral surface of the hard synthetic resin inner tube 1, a band-shaped heat insulating material 2 ′ made of a foamed polyethylene resin and having a vertically long parallelogram cross section is spirally wound at the same pitch as the above-mentioned hard synthetic resin band material. A heat insulating layer 2 is formed, and
A soft synthetic resin band made of semi-molten soft vinyl chloride resin is spirally wound around the outer peripheral surface of the foamed polyethylene resin heat insulating layer 2 at the same pitch as the hard synthetic resin band. Thus, the outer tube 3 having a certain thickness is formed.

As shown in FIG. 2, the inner tube 1 made of the hard synthetic resin is wider and thicker than the length in the longitudinal direction of the heat insulating hose in the band-shaped heat insulating material 2 'made of foamed polyethylene resin on which the heat insulating layer 2 is formed. Is a film-shaped or sheet-shaped thin-walled hard synthetic resin band 1 ′ in a semi-molten state, which is １ ／ of the band-shaped member previously wound on a molding rotary shaft (not shown). An inner pipe having a certain thickness, which is formed by spirally winding the next strip portion with the above overlap width so that at least three layers of strip portions are overlapped and integrated in a state of being shifted in the length direction in the thickness direction. Is formed.

On the other hand, a strip-shaped heat insulating material having the heat insulating layer 2 formed thereon
2 ′ is formed in a parallelogram cross-section by mutually parallel front and rear surfaces 2a and 2b having a fixed width, and inner and outer end surfaces 2c and 2d narrower than these front and rear surfaces 2a and 2b. In the state where 2b is inclined at a constant angle length direction with respect to the center line of the hose, the inclined front surface 2a of the next heat insulating part is joined to the inclined rear surface 2b of the heat insulating material part wound earlier, Furthermore, only the inner and outer ends of the front and rear joining surfaces 2a and 2b are integrally bonded 4,
Then, the bonding surfaces between the bonding portions 4 and 5 are bonded without bonding.

The soft synthetic resin outer tube 3 covering the heat insulating layer 2 has a semi-molten soft synthetic resin band narrower than the hard synthetic resin band material 1 ′ forming the inner tube 1. Lumber
3 'is spirally wound at the same pitch on the heat insulating material 2' forming the heat insulating layer 2 as described above, and the previously wound belt-shaped material is wound.
It is formed by superimposing and integrating the opposing edge of the strip 3 'to be wound next on the edge of 3'.

The heat-insulating pipe thus configured maintains a rigid straight pipe shape that does not bend by the hard synthetic resin inner pipe 1, and furthermore, the inner and outer pipes 1, 3 are formed. Although the vinyl chloride resin or the ABS resin and the foamed polyethylene resin forming the heat insulating layer 3 are non-adhesive or difficult to bond, the heat insulating material 2 having the heat insulating layer 3 formed on the hard synthetic resin inner tube 1 is used. Is strongly press-fitted by pressure-tightening at the time of spiral winding, so that there is no danger that the inner tube 1 also has a cylindrical shape coming out of the heat insulating layer 3 formed in a cylindrical shape.

Further, when the heat insulating pipe is cut into a desired length, the heat insulating material 2 ′ wound spirally has a heat insulating material portion wound first and a heat insulating material portion wound next. Since the inner and outer ends of the joint surface are integrally bonded 4, 5, there is no danger that the end portion of the strip-shaped heat insulating material 2 'will protrude from the cut end of the pipe, and furthermore, the heat insulating material portion spirally wound. They are not separated from each other in the length direction of the hose via the bonding portions 4 and 5, and are also prevented from deviating from each other in the circumferential direction, so that a stable form is always maintained.

In the spirally wound strip-shaped heat insulating material 2 ',
To bond the inner and outer ends at the front and rear joining surfaces of the previously wound heat insulating material portion and the next wound heat insulating material portion,
Although an appropriate adhesive may be used, the bonding structure is such that the bonding end portion of the belt-shaped heat insulating material 2 'is melted by heating at the time of manufacture, and is fused after cooling. In addition, this adhesive part is a band-shaped heat insulating material wound spirally.
It may be provided continuously over the entire length of 2 ′, or may be a structure that is intermittently adhered. However, in the spirally wound band-shaped heat insulating material 2 ′, first one turn in the spiral direction It is necessary to bond at least one portion of the heat insulating material portion and the heat insulating material portion wound next in a spiral direction so as to overlap the heat insulating material portion.

Next, a method of manufacturing a heat-insulating pipe having such a structure will be described. First, a belt-like material made of a hard synthetic resin such as a hard vinyl resin or a hard ABS resin in a semi-molten state having a fixed width and thickness. When the 1 ′ is spirally wound on a forming rotary shaft (not shown) while being extruded from a forming nozzle (not shown), as in a known manner, it is then wound on the previously wound strip 1 ′. The strip-shaped material 1 'to be formed is spirally wound so that the widths of 1/2 to 2/3 overlap each other, and the polymerized portion is fused and integrated to form the hard synthetic resin inner tube 1. To go.

Further, a cross-section made of the above-mentioned foamed polyethylene resin is formed without forming a hollow helical protrusion having a built-in core wire on the outer peripheral surface of the band-shaped material 1 'forming the inner tube 1 like a conventional flexible heat insulating pipe. The vertically long parallelogram-shaped heat insulating material 2 ′ is directly wound in a continuous spiral shape at the same spiral pitch as the above-mentioned band-shaped material 1 ′. At this time, the inclined rear surface 2b of the heat insulating material portion wound first in the helical direction and the inclined front surface 2a of the heat insulating material portion wound in the next helical direction are sequentially joined in a superimposed state to form the heat insulating layer 2. Front and back surfaces 2a joined to each other
The inner peripheral end of 2b is bonded and integrated. The bonding portion 5 is a semi-molten strip material 1 ′ forming the hard synthetic resin inner tube 1.
When the band-shaped heat insulating material 2 'is wound thereon, it is performed by keeping the temperature of the band-shaped material 1' at the melting temperature of the foamed polyethylene resin, and joined together by the heat of the high-temperature band-shaped material 1 '. The bonding portion 5 on the inner end side is formed by fusing the inner peripheral end of the joining surface of the belt-shaped heat insulating material portion.

Next, on the outer peripheral surface of the heat insulating layer 2, a strip material 3 'made of a semi-molten soft vinyl chloride resin having a fixed width.
Is extruded from a forming nozzle (not shown), and the front end edge of the band portion to be wound next is superimposed on the rear end edge portion of the band portion wound first, and the band heat insulating material 2 is fused. The outer tube 3 is formed by spirally winding at the same pitch as that of '. At this time, the outer peripheral end portions of the joining surfaces of the front and rear heat insulating material portions joined to each other are integrally fused by the high heat of the strip-shaped heat insulating material 3 ′ in the same manner as the fusion and integration of the inner end portions. The bonding portion 4 on the end side is formed.

The heat insulating pipe is manufactured in this manner. However, since the cross-sectional shape of the heat insulating material 2 'is formed as a vertically long parallelogram, the inclined rear surface 2b of the previously wound heat insulating material portion is formed.
In contrast, the inclined front surface 2a of the heat insulating material portion to be wound next is joined in a state of being shifted inward. Therefore, the heat insulation layer 2
Is formed in a mountain-shaped spiral ridge, and an outer tube 3 is integrally coated on the outer peripheral surface.

In the above manufacturing method, the strip-shaped materials 1 ', 3' made of synthetic resin in a semi-molten state extruded from the forming nozzle to form the inner and outer tubes 1, 3 are spirally wound on a forming rotary shaft. At the time of mounting, by maintaining the temperature in the semi-molten state at the melting temperature of the foamed polyethylene resin forming the heat insulating layer, the band-shaped heat insulating material 2 ′ made of the foamed polyethylene resin is bonded to the bonding surface of the mutually bonded heat insulating parts. Although the inner and outer ends are welded, at least one of the inner and outer ends of the joint surface may be fused and integrated.

As means for fusing and integrating at least one of the inner and outer ends of the joint surface of the heat insulating material portion, a belt-like material for forming the inner and outer tubes 1 and 3 by using an appropriate heating means is used. It may be carried out by forcibly heating 1 'and 3'.Also, a suitable adhesive may be applied to a suitable portion of the joint surface of the heat insulating material portion at the time of production of the heat insulating pipe so that a part of the joint surface is mutually bonded. It may be bonded and integrated. Furthermore, the band-shaped heat insulating material 2 ′ is not limited to the above-described vertically long parallelogram, but may be a rectangular cross-section. In short, any band-shaped material having a square cross-section may be used. May be an olefin resin such as a soft polyethylene resin or a polypropylene resin in addition to the soft vinyl chloride. Further, the resin forming the heat insulating layer 2 may be an olefin-based foamed resin such as foamed polypropylene other than the foamed polyethylene resin.

[0026]

As described above, according to the present invention, a heat insulating material made of a foamed resin is spirally wound around the outer peripheral surface of a cylindrical hard synthetic resin inner tube to form a heat insulating layer. In the heat insulating pipe, the outer peripheral surface of which is covered with a soft synthetic resin outer tube, the hard synthetic resin inner tube is formed by spirally winding a semi-molten hard resin band material. A heat-insulating pipe having a rigid hard resin inner tube by spirally winding a semi-molten hard resin band material, a band-shaped heat insulating material, and a soft synthetic resin band material sequentially on a molding rotary shaft while superposing them. Can be easily and efficiently manufactured, and a heat insulating pipe of stable quality can be provided.

Further, since the heat insulating layer is formed by spirally winding the belt-shaped heat insulating material on the hard resin inner tube, the band heat insulating material is firmly pressed on the hard synthetic resin inner tube by winding. Therefore, even when the band-shaped heat insulating material is made of an olefin resin foamed resin such as a foamed polyethylene resin which is non-adhesive or difficult to adhere to the synthetic resin forming the inner tube, it is wound into a cylindrical shape. There is no danger that the hard synthetic resin inner tube will fall out of the laminated heat insulating layer.

The heat insulating material made of an olefin-based foamed resin wound in a spiral shape integrally bonds a part of the joining surface between the previously wound heat insulating material portion and the next wound heat insulating material portion. Since the inner and outer tubes are formed of a synthetic resin that is non-adhesive or difficult to adhere to the olefin-based foamed resin, when the heat-insulated pipe is cut to a desired length, It is possible to reliably prevent the band-shaped heat insulating material from jumping out or being pulled out from the cut, and also to prevent the heat insulating material from partially moving in the length direction or the circumferential direction, and always maintain a stable form. Thus, piping work can be performed accurately and efficiently.

[Brief description of the drawings]

FIG. 1 is a simplified side view of a part of a heat-insulating pipe,

FIG. 2 is an enlarged sectional view of a part thereof.

[Explanation of symbols]

 Reference Signs List 1 inner tube made of hard synthetic resin 1 'strip made of hard synthetic resin 2 heat insulation layer made of foamed polyethylene resin 2' strip heat insulator 3 outer tube made of soft synthetic resin 4 outer end bonding portion 5 inner end bonding portion

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 04

Claims (3)

[Claims] A heat insulating material made of a foamed resin is spirally wound around the outer peripheral surface of a cylindrical hard synthetic resin inner tube to form a heat insulating layer, and the outer peripheral surface of the heat insulating layer is formed of a soft synthetic resin outer tube. Wherein the inner pipe made of hard synthetic resin is formed by spirally winding a band of hard synthetic resin in a semi-molten state. . 2. The heat insulating material wound on a hard synthetic resin inner tube is made of an olefin resin, and is a joining surface between a previously wound heat insulating material portion and a next wound heat insulating material portion. 2. The heat-insulating pipe according to claim 1, wherein at least the inner end or the outer end is bonded together. 3. A band in which a semi-molten hard synthetic resin band is wound first on a molding rotary shaft so that the next band has an overlapping width of 1/2 or more. Forming a rigid synthetic resin inner tube with a certain thickness that is integrated by being wound continuously and spirally at least three layers or more in the thickness direction, overlapping and integrated in a state of being shifted in the length direction Along with this, on the inner surface of the synthetic resin inner tube, a band-shaped material having a rectangular cross section made of a semi-molten olefin-based foamed resin is wound on the rear surface of the band-shaped material portion wound first, and then the band-shaped material portion wound next. A heat insulating layer is formed by spirally winding at least a part of the front surface while being fused, and a semi-molten soft synthetic resin strip having a certain width is first wound on the heat insulating layer. Front end of the next rolled strip on the rear edge of the strip A method for manufacturing a heat-insulating pipe, comprising forming an outer tube made of a soft synthetic resin by spirally winding an edge while fusing the edges.