JP2023085570A - Pipe conduit structure and connection method for pipe conduit structure - Google Patents

Abstract

To provide a resin pipe capable of visually recognizing that an outer peripheral surface of a pipe body has been scraped off in a state of being arranged in various directions.SOLUTION: A resin pipe 1 comprises a pipe body 11 made of an olefin-based resin, and a band-shaped part 13 formed on the outer peripheral surface of the pipe body so as to extend over the entire length of the pipe body 11, where a boundary line 13a between the pipe body 11 and the band-shaped part 13 is visible at any position in a circumferential direction of the pipe body 11, and the color difference in the L*a*b* color system defined in JIS Z8781-4:2013 is 1 or more between the colors of the pipe body 11 and the band-shaped part 13.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a pipeline structure and a method for connecting the pipeline structure.

Conventionally, the use of resin pipes (pipe bodies) made of olefinic resins such as polyethylene resins instead of metals has been studied for conveying fluids such as water. Corrosion of the pipe can be suppressed by forming the pipe from an olefin resin.
Since it is difficult for an adhesive to adhere to a resin pipe made of an olefin resin, an electrofusion method is used to extend or branch the resin pipe in the axial direction (see, for example, Patent Document 1). In the electrofusion method, the resin pipe and the electrofusion joint or the like are connected by heating and melting the resin pipe and the electrofusion joint or the like while they are in contact with each other.

An oxide film or the like is formed on the outer surface of the resin pipe. In the state where an oxide film or the like is formed, it is difficult to connect the electric fusion joint to the outer surface of the resin pipe. For this reason, an electric fusion joint or the like is electrically fused to the scraped portion of the outer surface of the resin pipe.

JP-A-2007-268628

In order to make it easier to know whether the outer surface of the resin pipe has been scraped off, a mark is written on the outer surface of the resin pipe with an oil-based pen or the like, and part of the mark is scraped off. If the remaining part of the mark is written on the resin pipe, it is possible to visually recognize that the outer surface of the resin pipe has been scraped off.
However, the work of marking the resin pipe is complicated. Further, it is desired that the mark can be visually recognized even if the resin pipe is arranged in various directions.

The present invention has been made in view of such problems. And it aims at providing the connection method of this pipeline structure.

In order to solve the above problems, the present invention proposes the following means.
The pipeline structure of the present invention is a pipeline structure comprising a resin pipe and an electrofused branch pipe, wherein the resin pipe comprises a pipe main body made of an olefin resin and an outer peripheral surface of the pipe main body. and a band-shaped portion formed to extend over the entire length of the pipe main body, and when the resin pipe is viewed in the axial direction of the pipe main body, it is adjacent to the outer peripheral surface of the resin pipe in the circumferential direction. All of the central angles with respect to portions between a plurality of boundary lines between the pipe body and the belt-shaped portion are 180° or less, and the colors of the pipe body and the belt-shaped portion are in accordance with JIS Z8781-4:2013. The color difference in the specified L*a*b* color system is 1 or more, and the electrofused branch pipe is fixed to the outer peripheral surface of the pipe main body, and the band-shaped portion along the outer peripheral surface of the pipe main body The circumferential length of a portion of the electrofused branch pipe that is in contact with the outer peripheral surface of the pipe body is longer than the circumferential length of the gap.

According to this invention, the color difference between the pipe main body and the band-shaped portion is 1 or more, and the boundary line between the pipe main body and the band-shaped portion can be visually recognized at any position in the circumferential direction. The boundary line between the pipe main body and the belt-like portion can be easily visually recognized in the state of being arranged in the direction.
Therefore, by visually confirming that the belt-like portion has been scraped off, it is possible to visually confirm that the outer peripheral surface of the pipe main body has been scraped off in a state in which the resin pipe is arranged in various directions.
Further, when connecting the resin pipe and the electrofused branch pipe by electrofusion, the outer peripheral surface of the pipe main body is extended along the circumferential direction from the length at which the electrofused branch pipe contacts the outer peripheral surface of the pipe main body. Remove long. Since the circumferential length of the portion of the electrofused branch pipe that is in contact with the outer peripheral surface of the pipe main body is longer than the circumferential length between the belt-shaped portions along the outer peripheral surface of the pipe body, At least a portion is removed. Therefore, it is possible to visually recognize that the outer peripheral surface of the pipe main body to which the electrofusion branch pipe is electrofused is scraped off.

Further, in the pipeline structure described above, the strip portion may have a thickness of 0.02 mm or more and 2.0 mm or less, and the pipe main body may be thicker than the strip portion.

Further, in the pipeline structure described above, a lead angle, which is an angle formed by the belt-like portion with respect to a plane perpendicular to the axis of the pipe body, may be 85° or more.
According to the present invention, it is possible to prevent the band-shaped portion from being inclined with respect to the axis of the pipe body, and the appearance of the band-shaped portion extending over the entire length of the pipe body from deteriorating.

Further, a method for connecting a pipeline structure of the present invention is a method for connecting a resin pipe for connecting any of the resin pipes described above and a tubular electric fusion joint, wherein the band-shaped portion of the resin pipe from the axial end of the pipe body longer than a predetermined insertion length along the axial direction; and after the removing step, inserting the resin pipe into the electric fusion joint and a fusion step of inserting the insertion length and electrically fusion bonding the resin pipe and the electrofusion joint.
According to this invention, the length of scraping off the band-shaped portion is longer than the length of inserting the resin pipe into the electric fusion joint. As a result, even after the resin pipe and the electric fusion joint are connected, the boundary line between the scraped portion and the remaining portion of the band-shaped portion is exposed to the outside, and the outer surface of the resin pipe is scraped off. can be seen.

According to the pipeline structure of the present invention, it is possible to visually recognize that the outer peripheral surface of the pipe body to which the electrofused branch pipe is electrofused is scraped off. Further, according to the pipe structure connection method of the present invention, even after the resin pipe and the electric fusion joint are connected, it is possible to visually recognize that the outer surface of the resin pipe has been scraped off.

1 is a perspective view of a resin pipe according to a first embodiment of the invention; FIG. It is a front view of the same resin pipe. It is an A1 direction arrow directional view in FIG. 3 is a view in the direction of arrow A2 in FIG. 2; FIG. It is a figure which shows typically the manufacturing apparatus of the same resin pipe. It is a side view of a pipeline structure provided with the same resin pipe and an electric fusion joint. FIG. 4 is a perspective view for explaining a removal step in the method for connecting resin pipes according to the first embodiment of the present invention; It is a side view of the resin pipe in the modification of 1st Embodiment of this invention. FIG. 4 is a perspective view of a pipeline structure according to a second embodiment of the present invention; It is the figure which expand|deployed the resin pipe of the same pipeline structure in planar shape. It is a side view explaining the method of measuring the width|variety of the strip|belt-shaped part of the same resin pipe. 1 is a photograph showing a resin pipe of Example 1 of the present invention. It is a photograph which shows the resin pipe of Example 2 of this invention. It is a photograph which shows the resin pipe of Example 3 of this invention. It is a photograph which shows the resin pipe of Example 4 of this invention. It is a photograph which shows the resin pipe of Example 5 of this invention.

(First embodiment)
A first embodiment of a resin pipe according to the present invention will be described below with reference to FIGS. 1 to 8 and 11. FIG.
As shown in FIGS. 1 and 2, the resin pipe 1 of this embodiment includes a pipe main body 11 and four belt-shaped portions 13. As shown in FIG. In the following figures, in order to distinguish between the tube main body 11 and the band-shaped portion 13, the band-shaped portion 13 is hatched with dots.
The pipe main body 11 is formed in a tubular shape using polyethylene resin, which is an olefin resin. The polyethylene resin may be a high density polyethylene resin, a medium density polyethylene resin, or the like. The olefin resin may be polypropylene resin, polybutene resin, or the like, in addition to polyethylene resin. For example, the thickness of the pipe body 11 (the radial length of the pipe body 11) is 5 mm or more and 50 mm or less. The length of the pipe body 11 is 5 m.
The olefin resin may contain inorganic fibers such as glass fibers, carbon fibers, and wollastonite. Furthermore, the pipe body 11 may be a multi-layer pipe in which other layers such as a layer containing inorganic fibers or a layer containing an oxygen barrier material and an olefin resin layer are laminated. When the pipe main body 11 is a multi-layer pipe, the band-shaped portion 13 is formed on the outermost layer for visibility. In order to connect with the electric fusion joint, it is preferable that the olefinic resin layer is positioned on the outer side of the other layers. is formed.
In the following description, the circumferential direction of the pipe body 11 is simply called the circumferential direction, and the radial direction of the pipe body 11 is simply called the radial direction.

The belt-like portion 13 is formed on the outer peripheral surface of the pipe body 11 . The band-shaped portion 13 extends over the entire length of the pipe body 11 . In this example, each strip 13 is arranged along the axis C of the pipe body 11 . The belt-like portions 13 are arranged around the axis C at regular intervals and at equal angles. The thickness of each band-shaped portion 13 (the radial length of the pipe body 11) is appropriately determined according to the thickness of the pipe body 11. For example, it is preferably 0.02 mm or more and 2.0 mm or less, and 0.05 mm or more. 1.0 mm or less is more preferable, and 0.1 mm or more and 0.5 mm or less is even more preferable. By setting the thickness of each band-shaped portion 13 within this range, the thickness is not too large, and the band-shaped portion 13 is eliminated by cutting the surface of the resin pipe 1 when connecting to the electric fusion joint. You can easily check what you have done. In addition, the thickness is not too small, and the color of the pipe body 11 cannot be seen through the band-shaped portion 13 from the outside, so that the band-shaped portion 13 can be distinguished. Note that the thickness of each belt-shaped portion 13 may be 0.3 mm or less. Furthermore, the thickness of the band-shaped portion 13 may be correlated with the thickness of the pipe body 11 . For example, since the thickness T1 of the pipe main body 11 differs for each nominal diameter, the preferred thickness T2 of the strip portion 13 may differ for each corresponding nominal diameter. For example, the ratio T1/T2 between the thickness T1 of the tube main body 11 and the thickness T2 of the band-shaped portion 13 may be 10 or more and 200 or less, preferably 20 or more and 150 or less. When the thickness is equal to or higher than the lower limit of this range, the band-shaped portion 13 does not become too thick with respect to the thickness of the pipe body 11, and the band-shaped portion 13 can be easily scraped off. Further, by making the thickness equal to or less than the upper limit of this range, the band-shaped portion 13 has a sufficient thickness, and the identification ability of the band-shaped portion 13 can be sufficiently exhibited. Further, the band-shaped portion 13 may be formed by co-extrusion with the tube body 11, for example, or may be printed on the surface of the tube body 11 after the tube body 11 is extruded.
It is preferable that the circumferential length of the band-shaped portion 13 is constant regardless of the position of the pipe body 11 in the direction of the axis C. As shown in FIG.

The radial width of the band-shaped portion 13 is appropriately determined according to the outer diameter of the pipe body 11, and is preferably 4 mm or more and 50 mm or less, preferably 8 mm or more and 40 mm or less. Also, the ratio of the width of the band-shaped portion 13 to the outer diameter of the pipe body 11 is 5% or more and 30% or less, preferably 7% or more and 25% or less. The ratio of the width of the band-shaped portion 13 to the outer diameter of the pipe body 11 as used herein means a value obtained by dividing the width of the band-shaped portion 13 by the outer diameter of the pipe body 11, which is 100 times. By setting the width of the band-shaped portion 13 within this range, the band-shaped portion 13 is not too narrow, so that the band-shaped portion 13 can be distinguished from any direction. Moreover, since the width is not too wide, it is possible to suppress an increase in manufacturing cost.

Note that the radial width of the band-shaped portion 13 can be measured using a known vernier caliper 71 as shown in FIG. 11, for example. When the slider 73 is moved along the main body 72 of the vernier caliper 71 and the belt-shaped portion 13 to be measured is in the state shown in FIG. 76a is aligned with each of the first boundary lines 13a of the belt-shaped portion 13, respectively. At this time, it is preferable that the outer measurement surfaces 75 a and 76 a be arranged along the axis C of the pipe body 11 .
The width of the belt-like portion 13 is measured by reading the values and scale displayed on the display portion 77 of the vernier caliper 71 . The width of the band-shaped portion 13 is defined by such a measuring method.

As shown in FIGS. 1 and 2, the exposed surface 11a of the pipe body 11 on which the band-shaped portion 13 is not formed on the outer peripheral surface of the pipe body 11 and the outer surface of the band-shaped portion 13 are flush with each other. The radial step at the connecting portion between the exposed surface 11a of the tube main body 11 and the outer surface of the band-shaped portion 13 is preferably 2.0 mm or less, and substantially no step. In the circumferential direction, the length of the exposed surface 11a of the pipe body 11 and the length of the outer surface of the band-shaped portion 13 may be equal to each other or may be different from each other. It is preferable that the length of the exposed surface 11 a of the pipe body 11 is longer than the length of the outer surface of the band-shaped portion 13 . It should be noted that the four belt-shaped portions 13 do not have to be arranged around the axis C at equal angles. The number of band-shaped portions 13 provided in the resin pipe 1 is not particularly limited, and may be one to three, or may be five or more.

The band-shaped portion 13 is preferably made of the same material as the pipe body 11 .
The color difference (ΔE) in the L*a*b* color system defined in JIS Z8781-4:2013 is 1 or more between the colors of the tube body 11 and the belt-like portion 13 . This color difference is preferably 5 or more, more preferably 10 or more, and even more preferably 30 or more. For example, the tube body 11 is blue and the band 13 is red.
The lightness (L*) in the L*a*b* color system defined in JIS Z8781-4:2013 in the color of the tube body 11 or the color of the band-shaped portion 13 is preferably 20 or more, and 30 or more. is more preferable. When the lightness of the color of the pipe body 11 or the band-shaped portion 13 is 20 or more, the pipe body 11 or the band-shaped portion 13 can be visually recognized even in a dark place such as a pipe space where the resin pipe 1 is installed. In the above color system, when L is 40 or more (preferably 50 or more) and both the absolute value of a and the absolute value of b are 10 or less, the belt-like portion 13 can be gray. A gray resin pipe 1 is used as a drain pipe in a building structure in Japan. Therefore, for example, by making the belt-like portion 13 gray, it is possible to suggest that the resin pipe 1 is used as a drainage pipe without making the pipe main body 11 itself gray. As a result, for example, by adopting a pipe body 11 of a common color (for example, blue) for the water supply pipe and the drain pipe, and adding the band-shaped portion 13 only to the pipe body 11 used as the drain pipe, the water supply pipe and the drain pipe Distinguishment from the drainpipe can be achieved. As a result, for example, the manufacturing cost can be reduced. In the drain pipe, the pressure of the fluid flowing inside is basically low, and the wall thickness of the pipe main body 11 can be made thin.

The color difference can be measured using a spectral color difference meter (handy type spectral color difference meter "NF333" manufactured by Nippon Denshoku Industries Co., Ltd.). It is preferable to measure the color difference in a darkened environment such as a dark room. Here, the color difference (ΔE) is calculated by the following formula (1).
ΔE=√((L1−L2) ² +(a1−a2) ² +(b1−b2) ² ) (1) In equation (1), L1, a1, and b1 are L2, a2, and b2 represent the lightness L, the red chromaticity a, and the yellow chromaticity b, respectively.

3 and 4 show arrow views in directions A1 and A2 in FIG. FIG. 3 is a side view of the resin pipe 1 viewed from a position facing the belt-like portion 13 in the circumferential direction of the pipe main body 11. As shown in FIG. 3 is a side view of the resin pipe 1 viewed from a position facing the exposed surface 11a of the pipe body 11 in the circumferential direction of the pipe body 11. FIG.

As shown in FIGS. 3 and 4, in the resin pipe 1, a first boundary line (boundary line) 13a, which is a boundary line in the circumferential direction between the pipe main body 11 and the strip portion 13, is defined. Two first boundary lines 13a are formed corresponding to each band-shaped portion 13 . The first boundary line 13a can be visually recognized from the outside of the resin pipe 1 when viewed from any position in the circumferential direction by the worker who performs the construction work of the resin pipe 1 .
The reason why the first boundary lines 13a are visible at any position in the circumferential direction is that, for example, the distance along the outer peripheral surface of the resin pipe 1 between the first boundary lines 13a adjacent in the circumferential direction It means less than half the length of the outer peripheral surface over the entire circumference. In other words, as shown in FIG. 2, of the outer peripheral surface of the resin pipe 1, the central angle _θ1 with respect to the portion between the circumferentially adjacent first boundary lines 13a is all 180° or less. do. In this example, since the four belt-shaped portions 13 are arranged at intervals of 90° around the axis C, the first boundary line 13a can be visually recognized at any position in the circumferential direction.

The first boundary line 13a may be visible at any position in the circumferential direction at the end of the pipe body 11 in the direction of the axis C. As shown in FIG. It is more preferable that the first boundary line 13a be visible at any position in the circumferential direction, regardless of the position of the pipe body 11 in the direction of the axis C. As shown in FIG.

As shown in FIG. 1, the exposed surface 11a of the pipe body 11 is provided with a stencil (indicator) 15. As shown in FIG. The stencil 15 represents, for example, the product name, model number, etc. of the resin pipe 1 . The stencil 15 is formed by printing or the like using ink formed of a material or the like similar to that of the pipe body 11 . The stencil 15 is arranged along the axis C. As shown in FIG.

Next, a manufacturing apparatus for manufacturing the resin pipe 1 configured as described above will be described.
As shown in FIG. 5 , the manufacturing apparatus 51 includes a co-extrusion machine 52 , a cooling section 53 , a take-up machine 54 , a printing machine 55 and a cutting machine 56 . In addition, in FIG. 5, a portion of a molding die 52a, which will be described later, that forms a second flow path 52c is indicated by a chain double-dashed line so that the inside can be easily seen. The co-extrusion molding machine 52, the cooling unit 53, the take-up machine 54, the printer 55, and the cutting machine 56 are arranged in this order from the upstream side where the resin pipe 1 (the continuous resin pipe 1A described later) is conveyed toward the downstream side. are arranged side by side.

A molding die 52a of the co-extrusion molding machine 52 is formed with a first flow path 52b and a second flow path 52c. In this embodiment, four second flow paths 52c are formed in the molding die 52a. The four second flow paths 52c merge into the first flow path 52b from the side of the first flow path 52b. The resin material forming the pipe body 11 is supplied to the first flow path 52b in a molten state. The resin material forming the band-shaped portion 13 is supplied to the second flow path 52c in a molten state.
A continuous resin pipe 1A is extruded downstream from the molding die 52a. The continuous resin pipe 1A is formed by continuously connecting the resin pipes 1 in the axis C direction.

The cooling unit 53 is composed of a water tank or the like. The cooling unit 53 cools the continuous resin pipe 1A molded by the co-extrusion molding machine 52 using water or the like.
Although not shown, the take-up machine 54 has a plurality of tracks. The plurality of endless tracks are spaced apart from each other around the axis of the continuous resin pipe 1A. A plurality of endless tracks are in contact with the outer peripheral surface of the continuous resin pipe 1A. When each endless track rotates in a predetermined direction, the continuous resin pipe 1A is pulled downstream.

The printer 55 prints the stencil 15 on the exposed surface 11a and the like of the continuous resin pipe 1A. Note that the printer 55 may be arranged between the cooling section 53 and the take-up machine 54 . The cutting machine 56 cuts the continuous resin pipe 1A into a predetermined length to form the resin pipe 1. As shown in FIG.
The resin pipe 1 is manufactured by the manufacturing apparatus 51 described above.

Next, a method for connecting the resin pipe 1 configured as described above and the electric fusion joint will be described.
Here, the electric fusion joint will be described. As shown in FIG. 6, the electrofusion joint 21 is a known one and is formed in a cylindrical shape. The electric fusion joint 21 has a joint main body 22, a pair of connector mounting portions 23, and a heating wire (not shown).

The joint main body 22 is made of the same resin material as the resin pipe 1 and is formed in a cylindrical shape. The inner diameter of the joint body 22 and the outer diameter of the pipe body 11 are approximately the same. An end of the joint body 22 serves as a socket for the joint body 22 .
A stopper 25 is provided at the axial center of the joint body 22 on the inner peripheral surface of the joint body 22 . For example, the stopper 25 is formed in an annular shape. For example, in the axial direction of the joint main body 22, the length obtained by dividing the value obtained by subtracting the length of the stopper 25 from the length of the joint main body 22 by 2 is the insertion length for inserting the resin pipe 1 into the electric fusion joint 21. is _L1 . The insertion length _L1 is determined in advance according to the specifications of the electric fusion joint 21 and the resin pipe 1, and the like.

The color of the outer surface of the joint main body 22 is substantially the same as the color of either the pipe main body 11 or the band-shaped portion 13 of the resin pipe 1 to be inserted. As a result, it can be easily determined that the application of the electrical fusion joint connecting the resin pipes 1 is the same as that of the resin pipes 1 . In addition, that the color of the outer surface of the joint main body 22 is substantially the same as the color of the pipe main body 11 or the band-shaped portion 13 of the resin pipe 1 means that the mutual color difference is less than 10, and that the color difference is less than 8. Preferably, less than 5 is more preferred.
The color of the inner surface of the joint body 22 may be either the color of the pipe body 11 or the color of the band-shaped portion 13, or may be a different color. Also, the color of the outer surface of the joint body 22 may be the color of both the pipe body 11 and the band-shaped portion 13 . Furthermore, an identification member provided separately from the joint main body 22 may have the color of the pipe main body 11 or the band-shaped portion 13. to the joint body 22.

The heating wire is embedded in the inner peripheral surface of the joint body 22 . A heating wire generates heat when an electric current flows through it.
Each connector attachment portion 23 is attached to the outer peripheral surface of the end portion of the joint body 22 in the axial direction. The connector attachment portion 23 is electrically connected to the end of the heating wire.

Next, a method for connecting the resin pipe 1 will be described.
First, in the removal step (step S1), as shown in FIG. A known scraper is used for scraping. A scraper is a machine that scrapes off the outer peripheral surface of the pipe body 11 .
The length in the direction of the axis C to be removed is the length L ₂ along the direction of the axis C from the end of the pipe body 11 in the direction of the axis C (hereinafter referred to as the removal length L ₂ ). When scraping off the outer peripheral surface of the pipe body 11, all the four band-shaped portions 13 are scraped off in a range corresponding to the scraping length _L2 . That is, for example, about 0.3 mm of the outer peripheral surface of the pipe body 11 is scraped off. As shown in FIG. 6, the scraping length _L2 is longer than the insertion length _L1 .
With a general scraper, the thickness of the pipe body 11 that can be scraped off at one time is about 0.15 mm. When the outer peripheral surface of the pipe main body 11 is scraped twice over the entire circumference with a scraper, the outer peripheral surface of the pipe main body 11 is scraped off by about 0.3 mm.

Next, in the fusion step (step S3) _, as shown in FIG. The electrofusion joint 21 is electrofused. Since the scraping length _L2 is longer than the insertion length _L1 , the second boundary line 13b, which is the boundary line in the direction of the axis C between the scraped portion and the remaining portion of the band-shaped portion 13, is formed. The second boundary line 13b is exposed to the outside and can be visually recognized from the outside.
When electrofusion is performed, a connector of a joining controller (not shown) is connected to the connector mounting portion 23 . By operating the joining controller, current is applied to the heating wire of the electrical fusion joint 21 through the connector and the connector mounting portion 23 . The heating wire generates heat to temporarily melt the joint main body 22 of the electric fusion joint 21 and the pipe main body 11 of the resin pipe 1 , and the pair of resin pipes 1 are connected via the electric fusion joint 21 . This fusing step S3 is performed after the aforementioned removing step S1. All steps of the method for connecting the resin pipe 1 are completed as described above.

As described above, according to the resin pipe 1 of the present embodiment, the color difference between the pipe main body 11 and the band-shaped portion 13 is 1 or more, and the pipe main body 11 and the band-shaped portion 13 are at any position in the circumferential direction. Since the first boundary line 13a of is visible, the first boundary line 13a can be easily visually recognized in a state where the resin pipe 1 is arranged in various directions.
Therefore, by visually confirming that the belt-shaped part 13 has been scraped off, it is possible to visually confirm that the outer peripheral surface of the pipe body 11 has been scraped off in a state in which the resin pipe 1 is arranged in various directions. This can prevent so-called cross-connection in which the resin pipe 1 is connected to another type of resin pipe.

Further, according to the connection method of the resin pipe 1 of the present embodiment, the scraping length _L2 is longer than the insertion length _L1 . As a result, even after the resin pipe 1 and the electrofusion joint 21 are connected, the second boundary line 13b of the band-shaped portion 13 is exposed to the outside, and it is possible to visually recognize that the outer surface of the resin pipe 1 has been scraped off.

In addition, like the resin pipe 1B shown in FIG. The lead angle _θ2 , which is the angle formed, may be 85° or more and less than 90°. When the band-shaped portion 13 is arranged along the axis C of the pipe body 11, the lead angle _θ2 is 90°. By configuring in this way, it is possible to prevent the band-shaped portion 13 from being inclined with respect to the axis C of the pipe body 11 and the deterioration of the appearance of the band-shaped portion 13 extending over the entire length of the pipe body 11 .

The thickness of the band-shaped portion 13 of the resin pipe 1 may be 0.30 mm or less. In general, when using a scraper, the thickness of the resin pipe that can be scraped off at one time is about 0.15 mm. When the resin pipe is scraped with a scraper, unevenness may occur in scraping, so the outer peripheral surface of the resin pipe may be scraped twice. In the work of scraping the resin pipe 1 with a scraper, including measures against unevenness, the outer peripheral surface of the resin pipe 1 is scraped off by about 0.3 mm. The band-shaped portion 13 can be scraped off from the portion.
The thickness of the band-shaped portion 13 of the resin pipe 1 may be 0.15 mm or less. By configuring in this way, the band-shaped portion 13 can be scraped off from the pipe body 11 by scraping the entire outer peripheral surface of the pipe body 11 with a scraper once.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. 9 and 10. Parts that are the same as those of the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. explain.
As shown in FIGS. 9 and 10, the pipe structure 2 of this embodiment includes the resin pipe 1 described above and an electrofused branch pipe 31 . In FIG. 10 , the range where the support plate 32 (described later) of the electrofused branch pipe 31 is in contact with the outer peripheral surface of the pipe main body 11 is indicated by a chain double-dashed line.
The electrofused branch pipe 31 has a support plate 32, a branch pipe 33, a connector mounting portion 34, and a heating wire (not shown).

The support plate 32 is formed in a shape in which a plate material is curved into a semi-cylindrical shape. The inner diameter of the inner surface of the support plate 32 (curvature radius of the pipe body 11 in the circumferential direction) and the outer diameter of the pipe body 11 are approximately the same.
The branch pipe 33 protrudes outward from the outer surface of the support plate 32 . The branch pipe 33 penetrates the support plate 32 . The outer diameter of the branch pipe 33 is smaller than the outer diameter of the pipe main body 11 of the resin pipe 1 . The heating wire is embedded in the inner surface side of the support plate 32 . Each connector attachment portion 34 is attached to the outer surface of the support plate 32 so as to sandwich the branch pipe 33 in the axis C direction. The connector attachment portion 34 is electrically connected to the end of the heating wire.
The support plate 32 of the electrofused branch pipe 31 is fixed to the outer peripheral surface of the pipe main body 11 by electrofusion.

The outer peripheral surface of the resin pipe 1 is partially scraped off in the circumferential direction by a known hand scraper or the like. Here, the circumferential length of the inner surface of the support plate 32, which is the portion of the electrofused branch pipe 31 that is in contact with the outer peripheral surface of the pipe main body 11, is defined as a contact length _L4 . The contact length _L4 is shorter than the removal length _L5 , which is the circumferential length of the removal region R, which is the range where the outer peripheral surface of the resin pipe 1 is removed. Since the support plate 32 of the electrofused branch pipe 31 is arranged in the cutout region R of the resin pipe 1, the contact length _L4 is shorter than the cutout length _L5 . Similarly, the length of the inner surface of the support plate 32 in the axis C direction is shorter than the length of the deletion region R in the axis C direction.
In addition, the contact length _L4 is longer than the inter-band length _L6 , which is the circumferential length between the band-shaped portions 13 along the outer peripheral surface of the pipe body 11 . Therefore, at least a portion of the belt-like portion 13 is scraped off when forming the deletion region R in the resin pipe 1 . Accordingly, a third boundary line 13c is formed between the scraped portion of the band-shaped portion 13 and the remaining portion without being scraped off. This third boundary line 13c can be visually recognized from the outside even after the resin pipe 1 and the electrofusion branch pipe 31 are connected by electrofusion. When the resin pipe 1 and the electrofused branch pipe 31 are connected, the conduit inside the pipe main body 11 of the resin pipe 1 and the conduit inside the branch pipe 33 of the electrofused branch pipe 31 communicate with each other.

As described above, according to the pipeline structure 2 of the present embodiment, when the resin pipe 1 and the electrofusion branch pipe 31 are connected by electrofusion, the outer peripheral surface of the pipe main body 11 is extended along the circumferential direction. Then, the electrofused branch pipe 31 is scraped off over a deleted length L ₅ longer than the contact length L ₄ at which the outer peripheral surface of the pipe main body 11 contacts. Since the contact length _L4 is longer than the length _L6 between the strips, at least part of the strips 13 is scraped off. Therefore, it can be visually recognized from the third boundary line 13c that the outer peripheral surface of the pipe main body 11 to which the electrofusion branch pipe 31 is electrofused is scraped off.

As described above, the first embodiment and the second embodiment of the present invention have been described in detail with reference to the drawings. change, combination, deletion, etc. of Furthermore, it goes without saying that the configurations shown in the respective embodiments can be used in combination as appropriate.
For example, in the first and second embodiments, the stencil 15 may not be provided on the resin pipe.

Next, Examples 1 to 5 of the resin pipe 1 according to the first embodiment will be described. In Examples 1 to 5, as shown in Table 1 to be described later, the diameters (nominal diameters) are different from each other.

Table 1 shows the measured values of the L*a*b* color system in the band-shaped portion 13 of Examples 1 to 5 (resin pipes 10A to 10E). In Table 1, measured values of three types of L*a*b* color system are described for each example. Each of these shows the results of measurements taken at three different locations on the band-shaped portion 13 .

Table 2 shows the measured values of the L*a*b* color system in the pipe bodies 11 of Examples 1 to 5.

Table 3 shows the color difference ΔE between the band-shaped portion 13 and the pipe body 11 of Examples 1 to 5. In addition, in Table 3, three kinds of color difference ΔE are described for each example. These show the results of measurements taken at three different locations on the band-shaped portion 13 and the pipe body 11, respectively.

The resin pipes 10A-10E of Examples 1-5 are shown in FIGS. 12-16. Upon checking with the naked eye, it was recognized that the pipe body 11 was blue and the band-shaped portion 13 was gray, and the boundary line 13a between them could also be recognized.

For reference, Table 4 shows the values of the L*a*b* color system for five specimens of gray resin pipes used for conventional drainage pipes.

Reference Signs List 1, 1B resin pipe 2 pipeline structure 11 pipe main body 13 strip-shaped portion 13a first boundary line (boundary line)
21 electrofusion joint 31 electrofusion branch pipe L ₁ insertion length L ₄ contact length (length)
Length between _L6 strips (length)
P plane θ ₂ lead angle

Claims (4)

a resin pipe;
an electrofused branch pipe;
A pipeline structure comprising
The resin pipe is
a pipe body made of an olefin resin;
a band-shaped portion formed on the outer peripheral surface of the pipe body so as to extend over the entire length of the pipe body;
with
When the resin pipe is viewed in the axial direction of the pipe main body, the center of the outer peripheral surface of the resin pipe between a plurality of boundary lines between the pipe main body and the band-shaped portion that are adjacent in the circumferential direction all angles are 180° or less,
The color difference in the L*a*b* color system defined in JIS Z8781-4:2013 between the colors of the tube body and the strip-shaped portion is 1 or more,
The electrofused branch pipe is fixed to the outer peripheral surface of the pipe body,
The circumferential length of the portion of the electrofused branch pipe that is in contact with the outer peripheral surface of the pipe main body is greater than the circumferential length between the belt-shaped portions along the outer peripheral surface of the pipe main body. long pipeline structure. The strip portion has a thickness of 0.02 mm or more and 2.0 mm or less,
The pipeline structure according to claim 1, wherein the thickness of the pipe body is thicker than the thickness of the belt-like portion. 3. The pipeline structure according to claim 1, wherein a lead angle, which is an angle formed by said belt-like portion with respect to a plane perpendicular to the axis of said pipe body, is 85[deg.] or more. A pipeline structure connection method for connecting the resin pipe of the pipeline structure according to any one of claims 1 to 3 and a cylindrical electric fusion joint,
a removing step of removing the belt-like portion of the resin pipe from the axial end of the pipe body longer than a predetermined insertion length along the axial direction;
a fusion step of inserting the resin pipe into the electric fusion joint by the insertion length after the removal step, and electrically fusion-bonding the resin pipe and the electric fusion joint;
How to connect the pipeline structure.

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