JP7522681B2 - Corrugated pipes, composite pipes, and methods for installing and manufacturing composite pipes - Google Patents

Description

The present invention relates to a corrugated pipe that covers a flexible plastic pipe, a composite pipe that includes a flexible plastic pipe and a corrugated pipe, and a method for installing and manufacturing this composite pipe.

For example, flexible plastic pipes used for hot and cold water supply have a soft surface, so if they are installed as piping, they will rub against structures and be damaged. For this reason, composite pipes in which a flexible plastic pipe is covered with a flexible corrugated pipe are becoming more common.
As disclosed in Patent Document 1, a corrugated pipe is constructed by alternately arranging small diameter sections (which become annular valley sections when viewed from the outside) and large diameter sections (which become peak sections when viewed from the outside) each having a circular cross section in the pipe axial direction.

Patent No. 6706158

In the composite pipe of Patent Document 1, gaps are formed not only between the large diameter section of the corrugated pipe and the flexible plastic pipe, but also between the small diameter section and the flexible plastic pipe. Therefore, even if the composite pipe is installed in a specified position, when the pressure, flow rate, temperature, etc. of the fluid passing through the flexible plastic pipe suddenly changes, the flexible plastic pipe is likely to flutter and generate abnormal noises (so-called water hammer noises and thermal expansion noises).

In order to solve the above problems, one aspect of the present invention is a flexible corrugated pipe that covers a flexible resin pipe,
The flexible resin tube includes a foamed resin, has annular large diameter portions and small diameter portions alternately in a tube axial direction, and a cross-sectional shape of the large diameter portion has a curved convex portion and a straight portion spaced apart from each other in a first direction, and a pair of side portions that are disposed between both ends of the curved convex portion and both ends of the straight portion and face each other in a second direction perpendicular to the first direction, and the small diameter portion has a restraining portion that restrains the flexible resin tube in the tube radial direction.

According to the above configuration, the flexible resin tube can be held down by the restraining portion of the small diameter portion, so that the generation of abnormal noise can be suppressed even if the pressure, flow rate, temperature, etc. of the fluid flowing through the flexible resin tube suddenly changes.
Since the corrugated pipe contains a foamed resin, heat retention can be improved. In the large diameter portion, the corners where the straight portion and the pair of side portions intersect are added as insulating air layers, so heat retention can be further improved compared to when a corrugated pipe having a large diameter portion with a circular cross section is used.
By aligning the straight portion of the large diameter section with the surface of the building structure, the composite pipe can be stably installed on the building structure.

Another aspect of the present invention is a composite pipe including a flexible resin pipe and a flexible corrugated pipe made of foamed resin, the corrugated pipe having annular large diameter portions and small diameter portions alternately in the pipe axial direction, and covering the flexible resin pipe,
The cross-sectional shape of the large diameter portion has a curved convex portion and a straight portion that are spaced apart and opposed to each other in a first direction, and a pair of side portions that are arranged between both ends of the curved convex portion and both ends of the straight portion and that face each other in a second direction perpendicular to the first direction, and the small diameter portion has a restraining portion that restrains the flexible plastic tube in a tube diameter direction.

Preferably, the flexible resin tube is restrained by the restraining portion of the small diameter portion at a position closer to the straight portion than the curved convex portion of the large diameter portion in the first direction.
According to the above configuration, a thick insulating air layer is formed between the curved convex portion of the large diameter portion of the corrugated pipe and the flexible plastic pipe. Moreover, by arranging the straight portion along the surface of the building structure, the intrusion of cold air between the flexible plastic pipe and the surface of the structure can be suppressed, thereby further improving the heat retention function of the composite pipe. If the building structure has insulating and heat storage properties, by bringing the flexible plastic pipe closer to the building structure, the heat retention can be further improved and sudden temperature changes can be mitigated, which contributes to further suppressing the generation of abnormal noise.

Preferably, the flexible resin tube is restrained by the restraining portion at a center between the pair of side portions of the large diameter portion in the second direction.
According to the above-mentioned configuration, a predetermined insulating air layer can be formed between each of the sides of the large diameter portion of the corrugated pipe and the flexible resin pipe, thereby further improving heat retention.

In one embodiment of the composite pipe, the cross-sectional shape of the small diameter portion has a second curved convex portion located on the curved convex portion side of the large diameter portion, a second straight portion located on the straight portion side of the large diameter portion and parallel to the straight portion, and a pair of second side portions along the pair of side portions of the large diameter portion, and a central portion of the second curved convex portion and a central portion of the second straight portion are provided as the restraint portion.
According to the above-mentioned configuration, the small diameter portion does not have a special shape for a restraining portion, such as a locally protruding convex portion, and furthermore, the large diameter portion and the small diameter portion have similar shapes, so that molding is easy.

In another embodiment of the compound pipe, the reduced diameter section has at least three circumferentially spaced apart constraints.
According to the above-mentioned configuration, the flexible resin tube can be stably restrained in the tube diameter direction.

In the other embodiment, preferably, the small diameter portion has a second straight portion located on the straight portion side of the large diameter portion and parallel to the straight portion, and has two convex portions that are spaced apart in the circumferential direction from both ends of the second straight portion and protrude radially inward, and a central portion of the second straight portion and the convex portions are provided as the restraint portion.
According to the above-mentioned configuration, the flexible resin tube can be stably restrained in the tube diameter direction at three points. Moreover, only two protrusions are required, and molding can be performed smoothly.

Another aspect of the present invention is a method of installing a composite pipe, comprising the steps of: aligning the straight portion of the large diameter portion of the composite pipe with the surface of a building structure; placing the arc-shaped apex of a mounting member over the curved convex portion of the large diameter portion; and fixing a pair of fixing portions of the mounting member to the surface of the building structure, thereby installing the composite pipe on the surface of the building structure.
According to the above method, the special shape of the corrugated pipe can be utilized to stably install the pipe on the surface of the building structure using the mounting member.

Yet another aspect of the present invention is a method for manufacturing a composite pipe including a flexible resin pipe and a flexible corrugated pipe having annular large diameter portions and small diameter portions alternately formed in an axial direction thereof and covering the flexible resin pipe, the method comprising the steps of:
the corrugated pipe is formed by expanding the tubular resin in the pipe radial direction while moving the forming surface in the pipe axial direction, and forming the corrugated pipe; the corrugated pipe is formed by forming a cross-sectional shape of the large diameter portion into a shape having a curved convex portion and a straight portion which are spaced apart from each other in a first direction, and a pair of side portions which are disposed between both ends of the curved convex portion and both ends of the straight portion and which face each other in a second direction perpendicular to the first direction; and the corrugated pipe is formed by forming an inner circumferential surface of the small diameter portion inward in the pipe radial direction by foaming the resin, thereby forming a restraining portion which restrains the flexible resin pipe in the pipe radial direction.
According to the above method, the restraining portion can be formed by utilizing foaming of the resin.

Preferably, the extrusion port has an arc-shaped first slit portion and a straight second slit portion spaced apart from each other in the first direction, and a pair of third slit portions arranged between both ends of the first slit portion and both ends of the second slit portion and facing each other in the second direction, and the corrugated pipe molding portion molds the small diameter portion into a cross-sectional shape having a second curved convex portion located on the curved convex portion side of the large diameter portion, a second straight portion located on the straight portion side of the large diameter portion and parallel to the straight portion, and a pair of second side portions along the pair of side portions of the large diameter portion, and by foaming of the resin, a central portion of the second curved convex portion and a central portion of the second straight portion are provided as the restraining portion that restrains the resin flexible tube.
According to the above method, small diameter portions and large diameter portions having special shapes can be easily formed.

The present invention can suppress the generation of abnormal noise caused by sudden changes in the pressure, flow rate, and temperature of the fluid passing through a flexible resin tube, and can also improve heat retention.

1 is a side cross-sectional view showing a composite pipe according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 . This is a cross-sectional view taken along the line B-B in FIG. FIG. 2 is a schematic side view of the manufacturing apparatus for the composite pipe. 1 is a diagram showing an insertion port for inserting a flexible resin tube and an extrusion port for extruding a resin material at the tip surface of the extrusion nozzle of the manufacturing apparatus. FIG. FIG. 5 is a side cross-sectional view showing a composite pipe according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view corresponding to FIG. 2 showing a composite pipe according to a third embodiment of the present invention. FIG. 11 is a plan view of the composite pipe of the third embodiment. FIG. 11 is a cross-sectional view corresponding to FIG. 2 showing a composite pipe according to a fourth embodiment of the present invention. FIG. 11 is a cross-sectional view corresponding to FIG. 2 showing a composite pipe according to a fifth embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First embodiment (FIGS. 1 to 5)
1 to 3 show a composite pipe 1 according to a first embodiment of the present invention. The composite pipe 1 is used, for example, as a pipe for supplying cold water or hot water. The composite pipe 1 includes a flexible resin pipe 2 through which fluids such as cold water or hot water pass, and a flexible corrugated pipe 3 (corrugated pipe) as a coating layer that coats the outer periphery of the flexible resin pipe 2.

The cross-sectional shape of the flexible resin tube 2 is a constant circle over its entire length. Examples of materials for the flexible resin tube 2 include cross-linked polyethylene (PE-X), polyethylene (PE), high heat resistant polyethylene (PE-RT), polybutene, polypropylene (PP), and other synthetic resins. Furthermore, the flexible resin tube 2 may be a cross-linked polyethylene pipe (JIS K6769 Type E) with a polyethylene layer on the surface, or a composite resin pipe containing metal, such as a metal-reinforced multi-layer structure. The above are examples of materials for the flexible resin tube 2, and there are no particular limitations as long as the required performance, such as flexibility and fluid flowability, can be ensured.

The corrugated pipe 3 does not have a non-foamed resin layer and is composed of a single layer of foamed resin. Resin materials for the corrugated pipe 3 include cross-linked polyethylene (PE-X), polyethylene (PE), high heat resistant polyethylene (PE-RT), polybutene, polypropylene (PP), thermoplastic elastomer, thermosetting elastomer, plastomer, and other synthetic resins, and are not limited to a single material but may be a composite resin containing multiple materials. The above are examples of materials for the corrugated pipe 3, and there are no particular restrictions on the material for the corrugated pipe 3 as long as it can ensure the required performance, such as flexibility and protection for the resin flexible pipe 2.

The foaming agent for the corrugated pipe 3 is, for example, an inorganic chemical foaming agent or foamable microcapsules, but is not limited to these. Physical foaming agents such as fluorocarbons or supercritical fluids may also be used. The foaming ratio is adjusted by the mixing ratio of the foaming agent. The foaming ratio of the foamed resin that constitutes the corrugated pipe 3 is preferably 1.05 to 4 times, and more preferably has a lower limit of 1.1 times or more and an upper limit of 2.0 times.

As shown in FIG. 1, the corrugated pipe 3 has a corrugated cross-sectional shape along the pipe axis, and has annular large diameter sections 10 and annular small diameter sections 20 arranged alternately at a predetermined pitch along the pipe axis, and a connecting section 30 connecting these large diameter sections 10 and small diameter sections 20.

As shown in Figures 2 and 3, the cross-sectional shape of the large diameter section 10 of the corrugated pipe 3 is a so-called horseshoe shape that is symmetrical on both sides, and has an arc section 11 (curved convex section) and a straight section 12 that face each other in the vertical direction (first direction) in the figure, and a pair of side sections 13 that face each other in the horizontal direction (second direction perpendicular to the first direction) in the figure. The straight section 12 extends in the second direction. The arc section 11 is approximately semicircular, and its center is located on a line that passes through the center of the straight section 12 and extends in the vertical direction. The pair of side sections 13 are located between both ends of the arc section 11 and the straight section 12, extend linearly in the vertical direction, and form approximately a right angle with the straight section 12.

In this embodiment, the cross-sectional shape of the small diameter section 20 of the corrugated pipe 3 is also horseshoe-shaped like the large diameter section 10, and has an arc section 21 (second arc section) arranged on the arc section 11 side of the large diameter section 10, a straight section 22 (second straight section) arranged on the straight section 11 side, and a pair of side sections 23 (second side sections) along the pair of side sections 13. The straight sections 12, 22 of the large diameter section 10 and the small diameter section 20 are parallel to each other, and the side sections 13, 23 are also parallel to each other.
A distance D1 between the inner surfaces at the centers of the arcuate portions 11 and 21 is greater than a distance D2 between the inner surfaces of the straight portions 12 and 22 .

When the corrugated pipe 3 covers the flexible plastic pipe 2, the inner surfaces of the central portion 21a (restraint portion) of the arc portion 21 of the small diameter portion 20 and the central portion 22a (restraint portion) of the straight portion 22 are in contact with the outer peripheral surface of the flexible plastic pipe 2.

When laying the composite pipe 1 in a building , the flexible resin pipe 2 is not damaged even when dragged because it is covered with the corrugated pipe 3. In addition, the corrugated pipe 3 itself has a foaming ratio of 4 times or less, so that scratch resistance can be ensured.
When connecting the flexible resin tube 2 to the joint, the corrugated tube 3 is slid along the axial direction of the flexible resin tube 2 while being contracted, thereby exposing the end of the flexible resin tube 2 and allowing easy connection to the joint. The corrugated tube 3 is made of a single layer of foamed resin, and can be easily contracted.

2 and 3, the composite pipe 1 is fixed to a concrete floor surface 5 (the surface of a building structure) by a general-purpose saddle band 4 (mounting member). The saddle band 4 is made of, for example, a metal plate, and has an arc-shaped top 4a, legs 4b on both sides of the top 4a, and a fixing part 4c extending at a right angle from the lower end of the leg 4b. The straight part 12 of the large diameter part 10 of the corrugated pipe 1 is aligned so as to be almost in contact with the floor surface 5, and the top part 4a of the saddle band 4 is placed over the arc part 11, and the fixing part 4c is fixed to the floor surface 5, whereby the composite pipe 1 is installed on the floor surface 5. The same applies when the composite pipe 1 is installed on a wall surface or a ceiling surface.

As described above, when the composite pipe 1 is placed on the floor surface 5 by the saddle band 4, the resin flexible pipe 2 is restrained in the pipe diameter direction by the corrugated pipe 3. That is, the inner surfaces of the central portion 21a (restrained portion) of the arc portion 21 of the small diameter portion 20 and the central portion 22a (restrained portion) of the straight portion 22 are in contact with the outer circumferential surface of the resin flexible pipe 2, so that the resin flexible pipe 2 is restrained in the up-down direction. In addition, the interval between the arc portion 21 and the straight portion 22 becomes narrower from the central portions 21a and 22a toward the left and right, so that the resin flexible pipe 2 is also restrained in the left-right direction. Therefore, even if the pressure, flow rate, temperature, etc. of the fluid such as water or hot water passing through the inside of the resin flexible pipe 2 suddenly changes, the fluttering of the resin flexible pipe 2 can be suppressed, and the generation of abnormal sounds such as water hammer sounds and thermal expansion sounds can be suppressed.

The foamed resin constituting the corrugated pipe 3 absorbs shocks, which further suppresses the generation of abnormal noise.
Since the flexible resin pipe 2 is placed close to the concrete floor surface 5, which has heat storage properties, it is possible to mitigate sudden temperature changes and to attenuate abnormal noise. This also contributes to an improved effect of suppressing the generation of abnormal noise.

Since the distance D1 between the resin flexible tube 2 and the arcuate portion 11 of the large diameter portion 10 is wide, a thick insulating air layer can be formed between them. The distance D3 between the resin flexible tube 2 and the side portion 13 of the large diameter portion 10 is also larger than the distance D2 between the resin flexible tube 2 and the straight portion 12, forming a thick insulating air layer. An insulating air layer is also formed between the resin flexible tube 2 and the left and right side portions 23 of the small diameter portion 20.
Furthermore, the lower half of the internal space of the large diameter section 10 is defined in a rectangular shape by the straight section 12 and the pair of side sections 13, and insulating air layers are formed at both corners of the rectangular shape. Similarly, insulating air layers are formed at both corners of the small diameter section 20.
As described above, since an insulating air layer with a large cross-sectional area can be secured, the heat retention function can be improved.

The straight section 12 of the large diameter section 10 of the corrugated pipe 3 is in contact with the floor surface 5 or faces it with a small gap therebetween, and the gap between the straight section 22 of the small diameter section 20 and the floor surface 5 is also narrow, so it is possible to prevent cold air from entering between these straight sections 12, 22 and the floor surface 5. Furthermore, the concrete of the floor surface 5 functions as a heat insulating material, and the foamed resin layer of the corrugated pipe 3 also functions as a heat insulating layer. This further enhances the heat retention function.

4 shows a manufacturing apparatus 100 for the composite pipe 1. The manufacturing apparatus 100 includes a foaming resin supply section 110, an extrusion nozzle 120, and a corrugated pipe forming section .
Although detailed illustration is omitted, the foaming resin supplying section 110 includes a hopper for receiving the resin that is the raw material for the corrugated pipe 3, a heater for heating and melting the resin, a foaming agent adding section, and a cylinder and a screw for kneading and extruding the resin and the foaming agent. The raw material resin before being charged into the hopper may contain a foaming agent. The foaming resin supplying section 110 may be disposed vertically as shown in the figure, or horizontally.

5, the extrusion nozzle 120 has a passage opening 121 through which the flexible resin tube 2 passes, and an annular extrusion opening 122 formed to surround the passage opening 121. The passage opening 121 is circular, and its diameter is approximately equal to the outer diameter of the flexible resin tube 2.
The extrusion port 122 is so-called horseshoe-shaped and has an arc-shaped first slit portion 122a corresponding to the arc portion 21 of the small diameter portion 20, a straight-line second slit portion 122b corresponding to the straight portion 22 of the small diameter portion 20, and a pair of third slit portions 122c corresponding to a pair of side portions 23 of the small diameter portion 20.
A radially outer surface 122x that defines the extrusion port 122 has approximately the same shape and size as the outer contour of the cross section of the small diameter portion 20 of the above-mentioned corrugated pipe 3. A radially inner surface 122y of the extrusion port 122 is slightly larger than the inner contour of the cross section of the small diameter portion 20, and the centers of the first slit portion 122a and the second slit portion 122b are spaced apart from the passage port 121 by, for example, 0.5 to 2 mm.

The corrugated pipe forming section 130 (corrugator) is located downstream in the extrusion direction of the extrusion nozzle 120 (right side in Figure 4). The corrugated pipe forming section 130 is equipped with two upper and lower elliptical annular tracks 131, 132, and a large number of split dies 133, 134 that are aligned along the annular tracks 131, 132 and circulate as indicated by the arrows. The axis of the extrusion nozzle 120 passes between the two annular tracks 131, 132.

In the figure, the split mold 133 provided on the upper annular track 131 has a molding surface (not shown) for molding approximately the upper half of the corrugated pipe 20 shown in Figures 1 to 3, for example, and the split mold 134 provided on the lower annular track 132 has a molding surface for molding approximately the lower half of the corrugated pipe 20. The upper and lower split molds 133, 134 are joined near the extrusion nozzle 120 to form a cylindrical mold pair, and the molding surfaces can mold large diameter sections 10 and small diameter sections 20 with multiple pitches. In the molding surfaces of each of the split molds 133, 134, a suction port (not shown) is formed in the molding section for molding the large diameter section 10.

Manufacturing Process of Composite Pipe The composite pipe 1 is manufactured as follows.
The flexible resin tube 2 is prepared in advance by molding and hardening it, obtaining it, etc. This flexible resin tube 2 passes through a passage port 121 of the extrusion nozzle 120, and is sent out from the extrusion nozzle 120 to the corrugated pipe forming section 130 at a constant speed, and is sent between split dies 133 and 134 arranged on circulation tracks 131 and 132 and moving at the same speed.

In the foaming resin supply section 110, the resin is heated and melted, and a foaming agent is added in a predetermined compounding ratio to foam at a predetermined expansion ratio (preferably 1.2 to 4 times), and then the resin is supplied to the extrusion nozzle 120, and extruded from the extrusion port 122 of the extrusion nozzle 120 toward the corrugated pipe molding section 32 at the same speed as the flexible resin pipe 2.

The resin has not yet started to foam due to the high pressure inside the extrusion nozzle 120. Since the pressure applied to the resin decreases due to extrusion, foaming starts immediately after extrusion.
The resin is extruded into a tube having a horseshoe-shaped cross section that is substantially the same as that of the extrusion port 122. A gap of 0.5 to 2 mm is formed between the inner surface of the center of the arc portion and the straight portion of the tubular resin and the outer circumferential surface of the flexible resin tube 2.

The tubular resin enters the mated split dies 133 and 134 , and is expanded in diameter by the vacuum from the suction ports of the split dies 133 and 134 , reaching the molding surfaces of the split dies 133 and 134 , where it is molded into the corrugated pipe 3 .
The thickness of the corrugated pipe 3 increases radially inward due to foaming while passing through the corrugated pipe forming section 130. As a result, the central portion 21a of the arc portion 21 and the central portion 22a of the straight portion 22 of the small diameter portion 20 come into contact with the outer circumferential surface of the flexible resin pipe 2, completing the cross-sectional shape shown in Figures 1 to 3.
Except for the fifth embodiment described later, the mating surfaces of the split dies 133 and 134 are provided so as to avoid the restraint portion. Since the parting line cannot be a restraint portion, the restraint portion can obtain the flexibility as designed. In addition, when the corrugated pipe 3 is made first and then the flexible resin pipe 2 is inserted, no burrs are generated.

In this embodiment, the extrusion cross-sectional shape of the tubular resin is made horseshoe-shaped to match the small diameter section 20, so that the amount of expansion of the tubular resin when molding the small diameter section 20 can be essentially reduced to zero, and the large diameter section 10 also expands to a similar shape, improving moldability.
In this embodiment, the cross-sectional shape of the extruded tubular resin is not limited to a horseshoe shape, but may be a circle or other shape.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the same components as those already described, and the description thereof will be omitted.
Second Embodiment
The second embodiment shown in Fig. 6 is basically the same as the first embodiment. The difference is that in the first embodiment, the centers of the arcuate portions 21 of all the small diameter portions 20 contact the flexible resin tube 2 to restrain the flexible resin tube 2, but in this embodiment, the centers of the arcuate portions 21 of every other or every several small diameter portions 20 contact the flexible resin tube 2, and the arcuate portions 21A of the other small diameter portions 20A are separated from the flexible resin tube 2. In this second embodiment, the insulating air layer between the small diameter portions 20 and the flexible resin tube 2 can be increased, and the heat retention can be further improved.

In the embodiment of FIG. 6, the center portions of the straight portions 22 of all small diameter portions 20 contact the flexible resin tube 2 to restrain the flexible resin tube 2, but the center portions of the straight portions 22 of every other or every several small diameter portions 20 may contact the flexible resin tube 2, and the straight portions of the other small diameter portions 20 may be separated from the flexible resin tube 2.

Third Embodiment
7 and 8, the center of the arc portion 21B of the small diameter portion 20B does not contact the flexible resin tube 2. Instead, convex portions 25 (restraining portions) that protrude inward in the tube radial direction are formed on both sides of the arc portion 21B, and these convex portions 25 contact the flexible resin tube 2.
In this embodiment, the flexible resin tube 2 can be stably restrained at three points: the central portion 22a of the straight portion 22 and two protruding portions 25 spaced circumferentially from both ends of the straight portion 22.
In the third embodiment, the protrusions 25 may be formed only on every predetermined number of small diameter portions 20B.

Fourth Embodiment
9, similarly to the third embodiment, convex portions 25 are formed on both sides of the arc portion 21C of the small diameter portion 20C, and convex portions 26 (restraining portions) that protrude inward in the tube diameter direction are also formed on both sides of the straight portion 22C. In this embodiment, the four convex portions 25, 26 spaced apart in the circumferential direction come into contact with the outer circumferential surface of the flexible resin tube 2, thereby stably restraining the flexible resin tube 2 in the tube diameter direction.
In the fourth embodiment as well, the protrusions 25 may be formed only on every other or every several small diameter portions, and the protrusions 26 may be formed only on the other small diameter portions every other predetermined number of small diameter portions.
In this embodiment, the center of the straight portion 22C may be in contact with or separated from the flexible resin tube 2. The basic shape of the small diameter portion 20C does not have to be a horseshoe shape, and may be a circle or a rectangle.

Fifth Embodiment
10, the small diameter portion 20D has a circular cross-sectional shape and is in contact with the outer circumferential surface of the flexible resin tube 2 over its entire circumference. That is, the small diameter portion 20D has a restraining portion over its entire circumference.

The present invention is not limited to the above-described embodiment, and various aspects can be adopted.
The constraint of the flexible resin tube by the small diameter portion includes a constraint in a state where a small gap is provided instead of contact.
The curved convex portion is not limited to the arc portion of a constant radius as in the above embodiment, but may be formed into a mountain shape by three or more straight lines, or may be formed into a mountain shape by joining two parabolas.
The flexible resin tube may have a cross-sectional shape other than a circle. For example, in the first embodiment, the flexible resin tube may be horseshoe-shaped, and the corrugated tube may also be horseshoe-shaped and be in contact with the flexible resin tube over its entire circumference.
The corrugated pipe 3 may be made of a non-foamed resin and may have a multi-layer structure.

The present invention can be applied to water and hot water supply pipes, for example.

1 Composite pipe 2 Flexible resin pipe 3 Corrugated pipe 4 Saddle band (mounting member)
4a Top portion 4c Fixed portion 5 Floor surface (surface of building structure)
10 Large diameter portion 11 Circular arc portion (curved convex portion)
12 Straight portion 13 Side portion 20, 20A, 20B, 20C, 20D Small diameter portion 21 Circular arc portion (second curved convex portion)
21a: Central portion of arc portion (restraint portion)
22 Straight line part (second straight line part)
22a: Central portion of second straight section (restraint section)
25, 26 Convex portion (restraint portion)
100 Manufacturing device 110 Foaming resin supply section 120 Extrusion nozzle 121 Passage port 122 Extrusion port 130 Corrugated tube molding section

Claims (10)

A flexible corrugated pipe covering a resin flexible pipe,
The tube includes a foamed resin and has annular large diameter portions and small diameter portions alternately in a tube axial direction.
a cross-sectional shape of the large diameter portion has a curved convex portion and a straight portion which are spaced apart from each other and face each other in a first direction, and a pair of side portions which are disposed between both ends of the curved convex portion and both ends of the straight portion and face each other in a second direction perpendicular to the first direction,
A corrugated pipe, wherein the small diameter portion has a restraining portion that restrains the flexible resin pipe in a pipe diameter direction. A resin flexible tube;
a flexible corrugated pipe that contains a foamed resin, has annular large diameter portions and small diameter portions alternately arranged in a pipe axial direction, and covers the flexible resin pipe;
A composite pipe comprising:
a cross-sectional shape of the large diameter portion has a curved convex portion and a straight portion which are spaced apart from each other and face each other in a first direction, and a pair of side portions which are disposed between both ends of the curved convex portion and both ends of the straight portion and face each other in a second direction perpendicular to the first direction,
A composite pipe, wherein the small diameter portion has a restraining portion that restrains the flexible resin pipe in a pipe diameter direction. The compound pipe according to claim 2, characterized in that the resin flexible pipe is restrained by the restraining portion of the small diameter portion at a position closer to the straight portion in the first direction than the curved convex portion of the large diameter portion. The compound pipe according to claim 3, characterized in that the flexible resin pipe is restrained in the second direction by the restraining portion at the center between the pair of side portions of the large diameter portion. The compound pipe described in claim 4, characterized in that the cross-sectional shape of the small diameter portion has a second curved convex portion located on the curved convex portion side of the large diameter portion, a second straight portion located on the straight portion side of the large diameter portion and parallel to the straight portion, and a pair of second side portions along the pair of side portions of the large diameter portion, and the center of the second curved convex portion and the center of the second straight portion are provided as the restraint portion. The compound pipe according to claim 4, characterized in that the small diameter portion has at least three restraint portions spaced apart in the circumferential direction. The compound pipe according to claim 6, characterized in that the small diameter section has a second straight section located on the straight section side of the large diameter section and parallel to the straight section, and has two convex sections that protrude radially inwardly from both ends of the second straight section and are spaced apart in the circumferential direction, and the central section of the second straight section and the convex sections are provided as the restraint section. A method for installing a composite pipe, comprising: aligning the straight portion of the large diameter portion of the composite pipe according to any one of claims 2 to 7 along the surface of the building structure; placing the arc-shaped apex of the mounting member over the curved convex portion of the large diameter portion; and fixing a pair of fixing portions of the mounting member to the surface of the building structure, thereby installing the composite pipe on the surface of the building structure. A method for manufacturing a composite pipe including a flexible resin pipe and a flexible corrugated pipe having annular large diameter portions and small diameter portions alternately formed in an axial direction thereof and covering the flexible resin pipe, comprising the steps of:
The flexible resin tube is fed from an opening of an extrusion nozzle to a corrugated tube forming section,
The resin that will become the corrugated pipe is foamed at a predetermined foaming ratio and supplied to the extrusion nozzle, and the resin is extruded into a tubular shape from an annular extrusion port surrounding the passage port of the extrusion nozzle to the corrugated pipe forming section;
the corrugated pipe forming section has a forming surface for forming the large diameter portion and the small diameter portion alternately in a pipe axial direction, and the corrugated pipe is formed by expanding the tubular resin in a pipe radial direction while moving the forming surface in the pipe axial direction;
In the forming process of the corrugated pipe, the cross-sectional shape of the large diameter portion is formed to have a curved convex portion and a straight portion which are spaced apart from each other and opposed to each other in a first direction, and a pair of side portions which are disposed between both ends of the curved convex portion and both ends of the straight portion and which face each other in a second direction perpendicular to the first direction,
A method for manufacturing a composite pipe, characterized in that, in the corrugated pipe molding process, the inner surface of the small diameter portion is displaced radially inward by foaming the resin, thereby forming a restraining portion that restrains the flexible resin pipe in the radial direction. the extrusion port has an arc-shaped first slit portion and a linear second slit portion spaced apart from each other and facing each other in the first direction, and a pair of third slit portions disposed between both ends of the first slit portion and both ends of the second slit portion and facing each other in the second direction,
the corrugated pipe forming portion forms the small diameter portion into a cross-sectional shape having a second curved convex portion located on the curved convex portion side of the large diameter portion, a second straight portion located on the straight portion side of the large diameter portion and parallel to the straight portion, and a pair of second side portions along the pair of side portions of the large diameter portion,
The method for manufacturing a composite pipe according to claim 9, characterized in that, by foaming the resin, a central portion of the second curved convex portion and a central portion of the second straight portion are provided as the restraining portion that restrains the flexible resin pipe.

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