JP2003314981A - Heat exchanging resin pipe and its manufacturing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for manufacturing a heat exchanging resin pipe having good heat transfer efficiency. <P>SOLUTION: The device comprises an extruder 6 and a die connected to the extruder 6, the die consisting of an outer die 7 and an inner die 8. The inner die 8 has a recessed portion 9 formed in the outer periphery face at the end on the extrusion side in a constantly spaced manner in a peripheral direction. By using a motor for rotationally driving the inner die 8 via a speed reducer, the resin pipe 4 is extruded from the die with a protruded portion 5 being spirally formed on the inner periphery face thereof. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchange resin tube capable of improving heat transfer, and a method and apparatus for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a metal pipe having a high thermal conductivity is used for a heat exchange pipe such as a pipe used for a heat exchanger, but recently, a resin pipe may be used.

[0003]

The metal pipe corrodes due to long-term use, and scale adheres to block the inside of the pipe.
There was a problem that the heat transfer efficiency was reduced. On the other hand, the resin tube has the advantage that it does not corrode and scale does not easily adhere, but it has the drawback of having a lower thermal conductivity than the metal tube, and it has been required to increase the heat transfer efficiency. The present invention has been made in view of the above points, and an object of the present invention is to provide a resin tube for heat exchange capable of improving heat transfer, and a manufacturing method and apparatus thereof.

[0004]

According to a first aspect of the present invention, one of a refrigerant or a heat medium and a gas or a liquid that is cooled or heated by heat exchange between the refrigerant or the heat medium is in a pipe. Is a resin pipe through which heat is exchanged with the other outside of the pipe, and a convex portion and / or a concave portion is formed on the inner peripheral surface of the pipe.

According to the present invention, the heat transfer area is increased by the convex portions and the concave portions, the flow of the fluid flowing in the pipe is disturbed, the Prandtl Pr number is increased, the temperature boundary layer is thinned, and heat transfer is improved. Since the resin pipe of the present invention has a convex portion and a concave portion formed on the inner peripheral surface of the pipe, and the outer peripheral surface of the pipe is smooth and does not have a concave protruding portion, a resin joint or electric It can be plugged into a fusion joint and heat or electrical fused as is conventional.

The projections and depressions in the present invention may be formed continuously or discontinuously, and their cross-sectional shape may be circular, square, or any other shape. . The height of the convex portion and the depth of the concave portion may or may not be constant, but in order to increase the surface area per unit volume and heat transfer efficiency, in the case of the convex portion, the convex portion It is better to reduce the size of. For example, in the case of a rib having continuous convex portions, the heat transfer area per unit volume increases as the wall thickness decreases.

When forming the ribs, the ribs may be provided linearly in the axial direction of the tube, but are preferably provided spirally. This makes the flow of fluid more turbulent. It is desirable to use a material having a high thermal conductivity as the material of the resin tube.Also, a substance having a high thermal conductivity, such as metal powder or metal fibers, may be mixed in, or a large number of metal wires having a high thermal conductivity may be embedded. It is desirable to improve the thermal conductivity of the resin tube.

Therefore, the invention according to claim 2 is characterized in that the convex portion of the invention according to claim 1 is a continuous spiral rib, and the invention according to claim 3 is related to claim 1 or 2. The resin pipe of the invention is characterized in that powder or granular material made of a material having a high thermal conductivity is mixed, or a large number of wires made of a material having a high thermal conductivity are embedded.

As a material having a good thermal conductivity, a metal, especially inexpensive iron, can be cited as a preferable example.
The resin pipe used in each of the above inventions may be a single-layer pipe or a multi-layer pipe. In the case of a multi-layer pipe, it is desirable that the outer layer portion is made of a material that can be easily heat-fused or electrically fused with the joint, and the inner layer portion is made of a material having a high thermal conductivity.

The invention according to claim 4 relates to a method of manufacturing a heat exchange resin pipe having a convex portion and / or a concave portion formed on the inner peripheral surface of the resin pipe, wherein a resin sheet having a convex portion and / or a concave portion formed on one surface is used. The invention according to claim 5 is characterized in that it comprises a step of forming and a step of forming the sheet and then bending it in a circular shape to weld the abutting ends. It is characterized in that it comprises a step of forming and a step of forming a sheet, bending it into a circle, butting them together, supplying them to an extrusion molding machine, and coextruding them. In the former invention according to claim 4, a single-layer pipe is obtained, whereas in the latter invention according to claim 5, a multi-layer pipe is obtained.

The invention according to claim 6 relates to an apparatus for manufacturing a heat exchange resin pipe in which a convex portion and / or a concave portion is continuously formed on the inner peripheral surface of the resin pipe, and is attached to the extruder and the tip portion of the extruder. The die is characterized by comprising an outer die and an inner die concentrically arranged in the outer die and having at least a concave portion and / or a convex portion formed on the outer peripheral surface of the tip end portion on the extrusion side.

The inner die of the present invention may be fixed or may be rotatable. When the inner die is fixed, the resin pipe extruded from the die has a convex portion and / or a concave portion continuously formed in the inner surface of the pipe in the axial direction of the pipe, and when the inner die is rotated, a spiral convex portion and Alternatively, the recess is continuously formed on the inner surface of the tube.

The invention according to claim 7 is characterized in that, in the invention according to claim 6, a drive device for rotating the inner die is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A resin pipe 1 shown in FIG. 1 is made of polyethylene, and projections 2 extending in the pipe axial direction are formed on an inner peripheral surface at equal intervals in the circumferential direction. Resin tube 4 shown in FIG.
Is also made of polyethylene, and the convex portion 5 is spirally formed on the inner peripheral surface.

FIGS. 3 and 4 show a die connected to the extruder 6 in the apparatus for producing the resin pipe 1 shown in FIG. 1. The outer die 7 and the outer die 7 are concentrically fixedly arranged. The inner die 8 is formed of an inner die 8, and at the tip end on the extrusion side of the inner die 8, concave portions 9 are formed on the outer peripheral surface at regular intervals in the circumferential direction, and the resin pipe 1 extruded from the die has an inner peripheral surface on the inner peripheral surface. The concave portion 9 of the die 8 forms the convex portion 2 in the tube axis direction.

In the apparatus for manufacturing the resin pipe 4 shown in FIG. 2, the inner die 8 is rotationally driven by a motor (not shown) via a speed reducer, and the inner die 8 is rotated so that the convex portion 5 is spirally formed on the inner peripheral surface of the resin pipe. Extruded as it is formed. Figure 5
This is another die used in the manufacturing apparatus of the resin pipe 1, and the resin extruded toward the edge through the axial center of the inner die 11 adheres to the inner peripheral surface of the pipe 1 and is projected in the axial direction of the pipe. It is adapted to form part 2.

In the apparatus for manufacturing the resin pipe 11 shown in FIG. 2, the inner die 11 is also rotationally driven, whereby the convex portion 5 is formed in a spiral shape. The resin tube 13 shown in FIG. 6 is an inner layer 13a made of cross-linked polyethylene mixed with metal powder.
And a two-layer structure of an outer layer 13b made of non-crosslinked polyethylene, and a projection 14 is formed on the inner layer 13a so as to project in the tube axis direction.

FIG. 7 shows a die used in the apparatus for producing the resin pipe 13 shown in FIG. 6, and includes an outer die 17 connected to an extruder 16 for extruding non-crosslinked polyethylene, and a concentric circle inside the outer die 17. The inner die 18 has a groove 20 formed in the inner circumferential surface in the axial direction, and a guide 19 that bends the plate and rounds it into a circle.
The resin pipe 13 is manufactured as follows.

First, as shown in FIG. 8, the convex portion 14 is formed on one surface.
A plate 21 made of cross-linked polyethylene containing iron powder is formed by forming a plurality of pieces in the width direction and protruding in the longitudinal direction at regular intervals. Next, the plate 21 is passed through the guide 19 shown in FIG. The plate 21 is gradually bent by the guide 19, rolled into a circular shape, passed between the outer die 17 and the inner die 18, covered with the non-crosslinked polyethylene extruded from the extruder 16, and extruded.

[0020]

According to the resin tube for heat exchange of the invention according to the first aspect, the scale does not easily adhere, and there is no corrosion, and leakage from the joint occurs by heat fusion or electric fusion with the joint. Can be prevented,
The concave portion and / or the convex portion formed on the inner peripheral surface have the effect of increasing the heat transfer area and improving the heat transfer due to the turbulence of the flow. Since the outer peripheral surface of the pipe is smooth and has no unevenness like the conventional resin pipe, the outer peripheral surface of the pipe can be inserted into the heat-fusion or electro-fusion joint inserted in the joint for electric fusion.

When the concave portion and / or the convex portion are formed in a spiral shape as in the invention according to claim 2, the flow is more likely to be disturbed than when the concave portion and / or the convex portion is formed along the tube axis direction, and the heat transfer is performed. Is improved. As in the invention according to claim 3, the heat transfer of the resin pipe is improved by mixing powder or granules or fibers made of a material having a high thermal conductivity or embedding a large number of wires made of a material having a high thermal conductivity. Can be made.

According to the inventions according to claims 4 and 6, it is possible to obtain a resin pipe in which a convex portion and / or a concave portion is formed on the inner peripheral surface, and according to the invention according to claim 5, the same convex portion is formed on the inner peripheral surface. And / or it is possible to obtain a multi-layered resin tube in which the recess is formed and the inner and outer layers are made of different materials. Claim 7
According to the invention related to (1), it is possible to obtain a resin pipe in which a convex portion and / or a concave portion is formed in a spiral shape.

[Brief description of drawings]

FIG. 1 is a perspective view of a resin tube for heat exchange according to the present invention.

FIG. 2 is a perspective view of another embodiment of the heat exchange resin pipe according to the present invention.

FIG. 3 is a schematic cross-sectional view of the resin pipe manufacturing apparatus shown in FIG.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a schematic sectional view of another embodiment of the resin pipe manufacturing apparatus.

FIG. 6 is a perspective view of still another aspect of the heat exchange resin pipe.

FIG. 7 is a schematic sectional view of the resin pipe manufacturing apparatus shown in FIG.

FIG. 8 is a perspective view of a plate.

[Explanation of symbols]

1, 4, 13 ... Resin tubes 2, 5, 14 ... 7, 17 ... Outer die 8, 11, 18 ... Inner die 9 ... Recess 16 ... Extruder 19 ... Guide 20 ... Groove 21 ... Plate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29L 23:00 B29L 23:00 (72) Inventor Hiroaki Tanaka 6-chome Waki, Waki-gun, Yamaguchi Prefecture 1-2 F term in Mitsui Chemicals, Inc. (reference) 3H111 AA01 BA15 CB02 CB22 EA04 4F207 AG08 AH81 KA01 KA17 KL63

Claims (7)

[Claims] 1. A refrigerant or a heat medium, and one of a gas or a liquid that is cooled or heated by heat exchange between the refrigerant or the heat medium flows through the inside of the pipe and the other outside the pipe. A resin pipe for heat exchange between which heat exchange is carried out, wherein a convex portion and / or a concave portion is formed on the inner peripheral surface of the pipe. 2. The resin tube for heat exchange according to claim 1, wherein the convex portion is a continuous spiral rib. 3. A powder or granular material made of a material having a high thermal conductivity, a fiber or the like is mixed, or a large number of wires made of a material having a high thermal conductivity are embedded. Resin tube for heat exchange. 4. A heat exchange characterized by comprising a step of molding a resin sheet having a convex portion and / or a concave portion formed on one surface, and a step of molding the sheet and then bending it in a circular shape to weld the butt ends. Manufacturing method of resin pipe. 5. A step of molding a resin sheet having a convex portion and / or a concave portion formed on one surface, and a step of molding the sheet, bending it into a circular shape, butting them together, feeding them to an extrusion molding machine, and coextruding them. A method of manufacturing a resin tube for heat exchange, comprising: 6. A manufacturing apparatus for a heat exchange resin pipe, wherein a convex portion and / or a concave portion is continuously formed on the inner peripheral surface of the resin pipe, which comprises an extruder and a die attached to the tip of the extruder. A heat exchange resin tube characterized by comprising an outer die and an inner die that is concentrically arranged inside the outer die and has at least a concave portion and / or a convex portion formed on the outer periphery of the tip end on the extrusion side. apparatus. 7. The apparatus for manufacturing a resin pipe for heat exchange according to claim 6, further comprising a drive device for rotating the inner die.