Pipe body

Abstract

To provide a pipe body that allows visual confirmation of a wear state of an internal surface of the pipe body and a flow state in the pipe body from the outside with a simple structure.SOLUTION: A pipe body has a wear detection function. The pipe body is configured to laminate a plurality of inner pipes made of a transparent or translucent synthetic resin. At least one of the laminated inner pipes has a colored line that is partially colored in an axial direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tubular body consisting of a hose, tube, or the like, which is used when transporting a mixture of abrasive materials such as solids and liquid, such as slurry, powder, granules, pellets, etc., using a fluid such as compressed air in manufacturing plants, processing plants, etc., or when transporting a fluid containing granules or powder. [Background technology]

[0002] In the past, this type of tube would wear down over time due to contact with abrasive materials, and as the wear progressed, the hose would eventually crack or break, causing leakage accidents and production problems. However, if the replacement operation was too safe, a hose that was still fully usable would be replaced at an early stage, resulting in waste. Also, depending on the abrasive material and the conditions of use, for example, the wear of the inner layer may progress quickly due to high pressure and high speed flow. If the inner layer is lost due to wear and the wear progresses to the reinforcing layer or outer layer, which can be said to be the limit of the product's life, the pressure resistance may drop drastically, causing serious problems such as the hose body bursting.

[0003] To address these situations, i.e., to make it possible to detect wear, there is a hose that has an axial line on the outer surface of the inner tube, and allows one to visually check from the inside whether the line has become exposed to the inner surface due to progressing wear (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-78008 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the hose described in Patent Document 1 is inspected by shining a light on the inside, which makes the inspection cumbersome and leads to concerns that the inspection may be neglected. Therefore, particularly in usage conditions where wear progresses quickly, by the time the wear of the innermost layer progresses and it is detected that the hose needs to be replaced, cracks or breaks may have already occurred, causing leakage accidents, or in severe cases, there is a high risk of the hose body bursting.

[0006] The present invention is aimed at addressing such problems, and aims to provide a tube with a simple structure that allows visual inspection of both the wear condition on the inside of the tube and the flow condition inside the tube. [Means for solving the problem]

[0007] In order to achieve this objective, the present invention provides a tube body with a wear detection function, which is constructed by stacking multiple inner tubes made of transparent or translucent synthetic resin, and at least one of the stacked inner tubes has a colored line that is partially colored in the axial direction. In addition, in order to achieve the above-mentioned object, the present invention provides a tube body having a wear detection function, which is constructed by stacking a plurality of inner tubes made of transparent or translucent synthetic resin, and some of the stacked inner tubes each have a colored line that is partially colored in the axial direction, and each of the colored lines is arranged at a different position in the circumferential direction. Here, "some of the stacked inner tubes each have a color line that is partially colored in the axial direction" includes, for example, when there are three stacked inner tubes, an embodiment in which two of them are colored and the remaining one is not colored, and an embodiment in which all three are colored, but does not include an embodiment in which only one is colored. [Brief description of the drawings]

[0008] [Figure 1]1A to 1F are explanatory diagrams showing the overall configuration of a tube according to embodiment A of the present invention, where (a) is a front view, (b) is a perspective view, (c) is a side cross-sectional view, and (d) to (f) are side views showing the progress of wear. [Diagram 2] 4A to 4F are explanatory diagrams showing the overall configuration of a tube according to embodiment B of the present invention, where (a) is a front view, (b) is a perspective view, (c) is a side cross-sectional view, and (d) to (f) are side views showing the progress of wear. [Diagram 3] 1A to 1F are explanatory diagrams showing the overall configuration of a tube according to embodiment C of the present invention, where (a) is a front view, (b) is a perspective view, (c) is a side cross-sectional view, and (d) to (f) are side views showing the progress of wear. [Figure 4] 1A to 1F are explanatory diagrams showing the overall configuration of a tube according to embodiment D of the present invention, in which (a) is a front view, (b) is a partially see-through oblique view, (c) is a side cross-sectional view, and (d) to (f) are side views corresponding to the progression of wear. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. (Embodiment A) The tubular body A of embodiment A of the present invention is made of a hose or tube used for transporting a mixture of an abrasive material and liquid, such as a slurry, a powder, a granule, a pellet, etc., using a fluid such as compressed air, and has a wear detection function.

[0010] FIG. 1 is an explanatory diagram showing the overall configuration of a tube according to embodiment A of the present invention, in which FIG. 1(a) is a front view, FIG. 1(b) is a perspective view, FIG. 1(c) is a side cross-sectional view, and FIGS. 1(d) to (f) are side views showing the progress of wear.

[0011] 1(a) and 1(b), the tube A according to the embodiment A of the present invention is configured by laminating a first tube 1A, a second tube 2A, and a third tube 3A, which are made of synthetic resin and made of a transparent or semi-transparent material, in that order from the inside to the outside. That is, the material is not limited to a colorless transparent one, and may be a semi-transparent or colored transparent material that is less transparent than a transparent one, as long as a colored line, which will be described later, can be visually confirmed from the outside of the tube A.

[0012] Each tube has a color line that is partially colored in the axial direction. That is, the first tube 1A has a first color line 11A, the second tube 2A has a second color line 21A, and the third tube 3A has a third color line 31A. Each tube is obtained by simultaneously molding a transparent or semi-transparent part and a color line part by co-extrusion of a thermoplastic resin suitable for extrusion molding such as polyvinyl chloride. As the thermoplastic resin, general-purpose plastic, engineering plastic having a heat resistance of 100°C or more, and super engineering plastic having a heat resistance of approximately 150°C or more are appropriately used depending on the application. In addition, from the viewpoint of preventing abrasion, it is preferable to use a urethane-based material that is resistant to abrasion, especially for the innermost layer of the tube.

[0013] In embodiment A, the first colored line 11A, the second colored line 21A, and the third colored line 31A are arranged adjacent to each other with a small gap therebetween, as shown in FIG. 1(a). Here, as shown by the same hatching, the first colored line 11A, the second colored line 21A, and the third colored line 31A are all the same color. However, the third colored line 31A of the third tube 3A is a carbon line made of a conductive material. In other words, the third colored line 31A serves both the function of identifying wear and the function of earthing.

[0014] A reinforcing layer 4A is provided in a spiral shape on the outside of the third tube 3A. The material may be a reinforcing thread consisting of a single braid or a plurality of reinforcing wires consisting of monofilaments or multifilaments formed of transparent synthetic resin such as polyester or nylon (registered trademark). The shape of the reinforcing layer 4A may be a circular cross section as shown in Fig. 1(b) and Fig. 1(c), or may be an elliptical cross section, a substantially rectangular cross section, a semi-cylindrical cross section with an arc-shaped cross section at the radially outer tip, or a substantially trapezoidal cross section.

[0015] In the tube A with wear detection function according to embodiment A of the present invention, when transporting solids such as granules or powder or fluids containing granules or powder, the first colored line 11A is also worn away depending on the degree of wear on the inner surface of the first tube 1A due to contact with the solids or fluids on the inner surface of the tube A. When the first colored line 11A is completely worn away and disappears, the second tube 2A starts to be worn away next, and the second colored line 21A is also worn away depending on the degree of wear on the inner surface of the second tube 2A. When the second colored line 21A is completely worn away and disappears, the only line remaining is the third colored line 31A on the third tube 3A.

[0016] 1(d) to 1(f) are side views of a tube according to embodiment A of the present invention, showing various stages of wear progression. FIG. 1(d) shows the tube A at the beginning of use, and the first colored line 11A, the second colored line 21A, and the third colored line 31A can all be seen in side view. FIG. 1(e) shows a state in which wear of the tube A has progressed to a certain extent, and in side view, the first colored line 11A has disappeared, and only the second colored line 21A and the third colored line 31A are visible. FIG. 1(f) shows a state in which wear of the tube A has exceeded the limit of use, and in side view, the first colored line 11A and the second colored line 21A have disappeared, and only the third colored line 31A is visible.

[0017] In this way, the degree of wear can be identified by the total width of the colored lines. As shown in Figs. 1(d) to (f), as the wear progresses, the width of the colored lines narrows, so that the degree of wear can be visually confirmed from the outside. In that sense, the colored lines may be arranged adjacent to each other, but since there is a possibility that the change over time may not be correctly recognized when the inspector (observer) is replaced during the inspection, the adjacent colored lines are arranged at a distance from each other in a side view. By doing so, for example, it becomes possible to accurately recognize the degree of wear depending on whether or not the transparent part (or semi-transparent part) between the first colored line 11A and the second colored line 21A can be confirmed. In addition, in embodiment A, it is set so that the replacement time is reached when only the third colored line 31A is visible, that is, when the gap between the colored lines cannot be confirmed.

[0018] Since each colored line is partially colored in the axial direction, most of the circumferential portion of the pipe A is made of a transparent or translucent material. Therefore, each colored line does not impede visibility, and the flow status of the transported material flowing inside the pipe A can be clearly visually confirmed. As a result, accidents such as clogging of the transported material inside the pipe A can be more reliably prevented, improving safety.

[0019] By replacing the hose after checking that only the third colored line 31A is visible, wasteful premature replacement is avoided. Needless to say, this prevents overlooking wear identification and prevents situations such as leakage accidents caused by cracks or breaks or bursting of the hose body.

[0020] (Embodiment B) Next, a description will be given of the tubular body B according to embodiment B of the present invention. The tubular body B according to embodiment B of the present invention is made of a hose or tube used for transporting a mixture of an abrasive material and a liquid such as a slurry, a powder, a granule, or a pellet by a fluid such as compressed air, and has an abrasion detection function.

[0021] FIG. 2 is an explanatory diagram showing the overall configuration of a tube according to embodiment B of the present invention, in which FIG. 2(a) is a front view, FIG. 2(b) is a perspective view, FIG. 2(c) is a side cross-sectional view, and FIGS. 2(d) to (f) are side views showing the progress of wear.

[0022] 2(a) and 2(b), the tube B according to the embodiment B of the present invention is configured by laminating a first tube 1B, a second tube 2B, and a third tube 3B, which are made of synthetic resin and made of a transparent or semi-transparent material, in this order from the inside to the outside. That is, the material is not limited to a colorless transparent one, and may be a semi-transparent or colored transparent one, which has a lower transparency than a transparent one, as long as the colored lines described later can be visually confirmed from the outside of the tube B.

[0023] Each tube has a color line that is partially colored in the axial direction. That is, the first tube 1B has a first color line 11B, the second tube 2B has a second color line 21B, and the third tube 3B has a third color line 31B. Each tube is obtained by simultaneously molding a transparent or semi-transparent part and a color line part by strong extrusion of a thermoplastic resin suitable for extrusion molding such as polyvinyl chloride. As the thermoplastic resin, general-purpose plastic, engineering plastic having a heat resistance of 100°C or more, and super engineering plastic having a heat resistance of approximately 150°C or more are appropriately used depending on the application. In addition, from the viewpoint of preventing abrasion, it is preferable to use a urethane-based material that is resistant to abrasion, especially for the innermost layer of the tube.

[0024] In embodiment B, the first colored line 11B, the second colored line 21B, and the third colored line 31B are arranged adjacent to each other as shown in FIG. 2(a). However, this is sufficient as long as they are seen adjacent to each other in a side view. For example, the first colored line 11B may extend to the area of ​​the second colored line 21B so that they overlap. Similarly, the second colored line 21B may extend to the area of ​​the third colored line 31B so that they overlap. Also, as shown by different hatching, the first colored line 11B, the second colored line 21B, and the third colored line 31B are all different colors. However, the third colored line 31B of the third tube 3B is a carbon line formed of a conductive material. That is, the third colored line 31B has both a function for identifying wear and a function as an earth. It is also possible that the first colored line 11B and the third colored line 31B are the same color, and only the second colored line 21B is a different color. In addition, the shade of the color can be adjusted according to the layer depth, and the degree of identification can be adjusted by changing the color. Even with a darker color, the flow conditions inside the pipe can be visually observed from the outside.

[0025] A reinforcing layer 4B is provided in a spiral shape on the outside of the third tube 3B. The material may be a reinforcing thread consisting of a single braid or a plurality of reinforcing wires consisting of monofilaments or multifilaments formed of transparent synthetic resin such as polyester or nylon (registered trademark). The shape of the reinforcing layer 4B may be a circular cross section as shown in Fig. 2(b) and Fig. 2(c), or may be an elliptical cross section, a substantially rectangular cross section, a semi-cylindrical cross section with an arc-shaped cross section at the radially outer end, or a substantially trapezoidal cross section.

[0026] In the case of the tube B with wear detection function according to the embodiment B of the present invention, when transporting solids such as granules or powder or fluids containing granules or powder, the first colored line 11B is also worn away depending on the degree of wear of the inner surface of the first tube 1B due to contact with the solids or fluids on the inner surface of the tube B. When the first colored line 11B is completely worn away and disappears, the second tube 2B starts to be worn away next, and the second colored line 21B is also worn away depending on the degree of wear of the inner surface of the second tube 2B. When the second colored line 21B is completely worn away and disappears, the only line remaining is the third colored line 31B of the third tube 3B.

[0027] 2(d) to 2(f) are side views of a tube according to embodiment B of the present invention, showing various stages of wear progression. FIG. 2(d) shows the tube B at the beginning of use, and the first colored line 11B, the second colored line 21B, and the third colored line 31B can all be seen in side view. FIG. 2(e) shows a state in which wear of the tube B has progressed to a certain extent, and in side view, the first colored line 11B has disappeared, and only the second colored line 21B and the third colored line 31B are visible. FIG. 2(f) shows a state in which wear of the tube B has exceeded the limit of use, and in side view, the first colored line 11B and the second colored line 21B have disappeared, and only the third colored line 31B is visible.

[0028] In this way, the wear level can be identified by the total width of the colored lines. As shown in Fig. 2(d) to (f), as the wear progresses, the width of the colored lines narrows, so that the wear level can be visually confirmed from the outside. In addition, since the colors of the colored lines are different, the wear level can be more clearly recognized. If the first colored line 11B, the second colored line 21B, and the third colored line 31B are colored blue, yellow, red, etc., respectively, the inspector (observer) can be given an intuitive recognition that while blue is visible, it is safe, when blue disappears and only yellow and red are visible, caution is required, and when only red is visible, replacement is required in a dangerous situation. In this way, in the embodiment B, the state where only the third colored line 31B is visible, that is, the replacement time can be confirmed by the color and width of the colored line. Note that the color scheme of blue, yellow, and red is merely an example, and other color schemes are possible. However, since the inner colored lines are more significant in terms of indicating the wear level, it is advantageous to use darker colors.

[0029] Since each colored line is partially colored in the axial direction, most of the circumferential portion of the pipe B is formed of a transparent or semi-transparent material. Therefore, each colored line does not hinder the view, and the flow condition of the transported material flowing through the pipe B can be clearly visually confirmed. As a result, accidents such as clogging of the transported material in the pipe B can be more reliably prevented, and safety can be improved. By arranging the first to third colored lines in multiple places in the circumferential direction, confirmation can be easily performed. Figures 2(a) and (b) show an example in which two sets of colored lines are arranged relatively to each other.

[0030] By checking the color change and making sure that only the third colored line 31B is visible before replacing the hose, wasteful premature replacement can be avoided. Needless to say, this prevents overlooking wear identification and prevents situations such as leakage accidents caused by cracks or breaks or bursting of the hose body.

[0031] (Embodiment C) Next, a description will be given of the tubular body C according to embodiment C of the present invention. The tubular body C according to embodiment C of the present invention is made of a hose or tube used for transporting a mixture of an abrasive material and a liquid such as a slurry, a powder, a granule, or a pellet by a fluid such as compressed air, and has a wear detection function.

[0032] FIG. 3 is an explanatory diagram showing the overall configuration of a tube according to embodiment C of the present invention, in which FIG. 3(a) is a front view, FIG. 3(b) is a perspective view, FIG. 3(c) is a side cross-sectional view, and FIGS. 3(d) to (f) are side views showing the progress of wear.

[0033] As shown in Figures 3(a) and 3(b), the tube C according to embodiment C of the present invention is constructed by laminating a first tube 1C, a second tube 2C, and a third tube 3C, which are made of synthetic resin and made of a transparent or semi-transparent material, in that order from the inside to the outside. That is, the material is not limited to a colorless transparent one, and may be a semi-transparent or colored transparent material that is less transparent than a transparent one, as long as the colored lines described later can be visually confirmed from the outside of the tube C.

[0034] Of the three tubes, only the second tube 2C has a colored line that is partially colored in the axial direction. That is, the second tube 2C has a colored line 21C, but the first tube 1C and the third tube 3C do not have a colored line. The second tube 2C is obtained by simultaneously molding a transparent or semi-transparent part and a colored line part by strong extrusion of a thermoplastic resin suitable for extrusion molding such as polyvinyl chloride, while the first tube 1C and the third tube 3C are obtained by extrusion molding of a single material. As the thermoplastic resin, general-purpose plastics, engineering plastics having a heat resistance of 100°C or more, and super engineering plastics having a heat resistance of approximately 150°C or more are appropriately used depending on the application. In addition, from the viewpoint of preventing wear, it is preferable to use a urethane-based material that is resistant to wear.

[0035] In the embodiments A and B, the reinforcing layer 4C is provided in a spiral shape on the outside of the third tube 3C, but in the embodiment C, no reinforcing material is provided. Also, as can be understood from the fact that the third tube 3C does not have a colored line, there is no carbon line. The embodiment C is a tube body of a simple laminated structure without a reinforcing material, and has a clean appearance. Of course, it is possible to provide a carbon line on the third tube 3C apart from the viewpoint of the wear detection function.

[0036] In the case of the tube C with wear detection function according to the embodiment C of the present invention, when transporting solids such as granules or powder or fluids containing granules or powder, the first tube 1C is worn down due to contact with the solids or fluids on the inner surface of the tube C. Eventually, the second tube 2C starts to be worn down, and the colored line 21C is also worn down at the same time depending on the degree of wear on the inner surface of the second tube 2C, and the color (density) gradually becomes lighter.

[0037] 3(d)-3(f) are side views of a tube according to embodiment C of the present invention, showing various stages of wear progression. FIG. 3(d) shows tube C at the beginning of use, and colored line 21C can be clearly seen in side view. FIG. 3(e) shows a state in which wear of tube C has progressed to a certain extent, and in side view, colored line 21C' appears lighter than colored line 21C at the beginning. FIG. 3(f) shows a state in which wear of tube C has exceeded the limit of use, and colored line 21C has disappeared in side view.

[0038] In this way, the degree of wear can be visually identified from the outside by the change in the colored line 21C. As shown in Figures 3(d) to (f), as the wear progresses, the appearance of the colored line changes, so the degree of wear can be confirmed.

[0039] Since the colored line 21C is partially colored in the axial direction, most of the circumferential portion of the pipe C is made of a transparent or semi-transparent material. Therefore, the colored line 21C does not impede visibility, and the flow status of the transported material flowing through the pipe C can be clearly visually confirmed. As a result, accidents such as clogging of the transported material in the pipe C can be more reliably prevented, improving safety.

[0040] By replacing the hose after checking that the colored line 21C is no longer visible, waste caused by replacing the hose prematurely can be avoided. Of course, it goes without saying that overlooking wear identification can be prevented, and the occurrence of situations such as leakage accidents caused by cracks or breaks or bursting of the hose body can be prevented.

[0041] (Embodiment D) Next, a description will be given of a tubular body D according to embodiment D of the present invention. The tubular body D according to embodiment D of the present invention is made of a hose or tube used for transporting a mixture of an abrasive material and a liquid, such as a slurry, a powder, a granule, or a pellet, by a fluid such as compressed air, and has a wear detection function.

[0042] FIG. 4 is an explanatory diagram showing the overall configuration of a tube according to embodiment D of the present invention, in which FIG. 4(a) is a front view, FIG. 4(b) is a partially see-through oblique view, FIG. 4(c) is a side cross-sectional view, and FIGS. 4(d) to (f) are side views showing the progress of wear.

[0043] 4(a) and 4(b), the tube D according to the embodiment D of the present invention is configured by laminating a first tube 1D and a second tube 2D, which are made of synthetic resin and made of a transparent or semi-transparent material, in this order from the inside to the outside. That is, the material is not limited to a colorless transparent one, and may be a semi-transparent or colored transparent one that is less transparent than a transparent one, as long as a colored line, which will be described later, can be visually confirmed from the outside of the tube D.

[0044] Of the two tubes, only the second tube 2D has a colored line that is partially colored in the axial direction. That is, the second tube 2D has a colored line 21D, but the first tube 1D does not have a colored line. The second tube 2D is obtained by simultaneously molding a transparent or semi-transparent part and a colored line part by strong extrusion of a thermoplastic resin suitable for extrusion molding such as polyvinyl chloride, but as shown in the front view of FIG. 4(a) and the partially see-through perspective view of FIG. 4(b), the colored line 21D is not arranged over the entire thickness of the second tube 2D. That is, the colored line 21D is arranged on the inside of the second tube 2D but not on the outside. As the thermoplastic resin, general-purpose plastic, engineering plastic having a heat resistance of 100°C or more, and super engineering plastic having a heat resistance of approximately 150°C or more are appropriately used depending on the application. In addition, from the viewpoint of preventing wear, it is preferable to use a urethane-based material that is resistant to wear.

[0045] In the tube D with wear detection function according to the embodiment D of the present invention, when transporting solids such as granules or powder or fluids containing granules or powder, the first tube 1D is worn down due to contact with the solids or fluids on the inner surface of the tube D. Eventually, the second tube 2D starts to be worn down, but the colored line 21D is not worn down at the beginning when the inner surface is being worn down. At a certain point, the colored line 21D starts to be worn down.

[0046] 4(d) to 4(f) are side views of the tube according to embodiment D of the present invention, showing various stages of wear progression. FIG. 4(d) shows the tube D at the beginning of use, and the colored line 21D can be clearly seen in side view. FIG. 4(e) shows the tube D in a state where wear has progressed to a certain extent, and in side view, 21D' appears thinner than the colored line 21D at the beginning. FIG. 4(f) shows the tube D in a state where wear has exceeded the limit of use, and in side view, the colored line 21D has disappeared. However, the second tube 2D still barely remains.

[0047] In this way, the degree of wear can be identified by the change in the colored line 21 D. As shown in Figures 4(d) to (f), as the wear progresses, the state of the colored line changes, so the degree of wear can be confirmed.

[0048] Since the colored line 21D is partially colored in the axial direction, most of the circumferential portion of the pipe D is made of a transparent or semi-transparent material. Therefore, the colored line 21D does not impede visibility, and the flow status of the transported material flowing through the pipe D can be clearly visually confirmed. As a result, accidents such as clogging of the transported material in the pipe D can be more reliably prevented, improving safety.

[0049] By replacing the filter after it is confirmed that the colored line 21D is no longer visible, waste caused by replacing the filter early is avoided. Compared with embodiments A to C, embodiment D is an embodiment suitable for a usage situation in which wear progresses relatively slowly.

[0050] The pipe body having a wear detection function for transporting fluids such as slurry, powder, granules, and pellets, which are mixtures of abrasive materials such as solids and liquids used in manufacturing plants and processing plants for foods including beverages, cosmetics, flavorings, medicines, and other products according to the embodiment of the present invention, has been described in detail with reference to the drawings, and its structure has been described. However, the specific configuration is not limited to these embodiments, and even if there are design changes within the scope of the present invention, they are included in the present invention. That is, the arrangement of the colored lines can be freely set, as shown by the arrangement variations of embodiments A to C. For example, in the drawings, the colored lines are provided in two places, but they may be provided in three or four places. However, since there is a requirement to check the flow condition inside the pipe, it is not appropriate to provide the colored lines in three or four places when they extend over multiple layers. However, when there is only one layer of colored lines, it is fully possible to provide them in four places. [Explanation of symbols]

[0051] A tube body 1A No. 1 tube 11A 1st coloring Riko 2A No. 2 tube 21A 2nd coloring Riko 3A No. 3 tube 31A The 3rd coloring Rino 4A reinforcement layer B tube body 1B No. 1 tube 11B 1st coloring Rino 2B No. 2 tube 21B 2nd coloring Rino 3B No. 3 tube 31B The 3rd coloring Rino 4B reinforcement layer C tube body 1C No. 1 tube 2C No. 2 tube 21C coloring ライン 3C No. 3 tube D tube body 1D No. 1 tube 2D No. 2 Tube 21D coloring ライン 3D No.3 Tube

Claims

1. A tube having a wear detection function, The tube body is configured by laminating a plurality of inner tubes made of transparent or translucent synthetic resin, At least one of the stacked inner tubes has a color line that is partially colored in the axial direction. A tube body characterized by:

2. A tube having a wear detection function, The tube body is configured by laminating a plurality of inner tubes made of transparent or translucent synthetic resin, Some of the stacked inner tubes each have a color line that is partially colored in the axial direction, and each of the color lines is disposed at different positions in the circumferential direction. A tube body characterized by:

3. Among the respective colored lines, adjacent lines are disposed adjacent to each other in a side view. The tube according to claim 2 .

4. Among the respective colored lines, adjacent lines are arranged to be spaced apart from each other in a side view. The tube according to claim 2 .

5. Adjacent lines among the colored lines are colored in different colors. The tube according to claim 2 .

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