Corrugated cladding pipe and composite pipe

Abstract

To avoid that an inner pipe is obliquely cut when cutting a corrugated cladding pipe simultaneously with the inner pipe.SOLUTION: A corrugated cladding pipe 20 for cladding a flexible inner pipe 10 comprises annular crest parts 21 and annular trough parts 22 which are alternately arranged in a pipe axial direction, and a plurality of holding protrusions 23 arranged with internals in the pipe axial direction, protruding radially inward rather than the crest parts, and holding the inner pipe by its tip so as to be substantially coaxial with a pipe axis. Recesses 25 corresponding to the holding protrusions 23 are formed at an external peripheral face of the corrugated cladding pipe 20. Arrangement intervals D of the holding protrusions 23 in the pipe axial direction are set so that the holding protrusions 23 do not interfere with a blade part 44 when the inner pipe is cut by the vertical abutment of the blade part 44 of a pipe cutter 40 on centers of the intervals D of the recesses 25 in the pipe axial direction in a state that the inner pipe 10 is cladded with the corrugated cladding pipe 20.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a corrugated cladding pipe that is fitted over a flexible inner pipe suitable for transporting a fluid, and to a composite pipe that includes this corrugated cladding pipe and the inner pipe. [Background technology]

[0002] A corrugated cladding pipe with alternating peaks and valleys is known as a flexible cladding pipe for protecting a flexible pipe (inner pipe) for hot and cold water supply. This corrugated cladding pipe is easily stretched in the axial direction of the pipe because the inner pipe needs to be exposed when connecting the inner pipe to a joint.

[0003] The following Patent Document 1 discloses a composite pipe in which a corrugated cladding tube having peaks and valleys is placed over an inner pipe. The corrugated cladding tube of this composite pipe has a first valley portion that does not contact the inner pipe, and a second valley portion that protrudes radially inward from the first valley portion and contacts the inner pipe. The second valley portion is arranged between a plurality of first valley portions and peaks in the tube axial direction, and holds the inner pipe concentrically with the tube axis of the corrugated cladding tube by its tip. That is, the second valley portion functions as a holding protrusion.

[0004] In the composite pipe of Patent Document 1, the elasticity of the corrugated cladding pipe and the reduction in the contact area between the corrugated cladding pipe and the inner pipe by the retaining protrusions allow the corrugated cladding pipe to follow the movement of the inner pipe even if the inner pipe moves in the axial direction due to thermal expansion, and friction between the corrugated cladding pipe and the inner pipe is reduced, thereby suppressing the generation of abnormal noise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-210041 A Summary of the Invention [Problem to be solved by the invention]

[0006] The composite pipe of Patent Document 1 is connected to a joint by inserting the inner pipe into the joint. If the tip of the inner pipe is cut at an angle, the water-stopping surface between the inner pipe and the water-stopping rubber ring in the joint is not stable, which may cause problems such as water leakage. Therefore, it is preferable that the inner pipe is cut perpendicular to the pipe axis.

[0007] When cutting the inner pipe together with the corrugated cladding pipe, i.e., the composite pipe, with a manual pipe cutter, the composite pipe is held in one hand and the pipe cutter is operated with the other. When the blade enters the corrugated cladding pipe, if there is a holding protrusion near the blade, the corrugated cladding pipe will be crushed unevenly near the holding protrusion, and the corrugated cladding pipe and the inner pipe will no longer be concentric. If the blade enters the inner pipe in this state, the inner pipe will be cut at an angle. In particular, if the holding protrusion interferes with the blade, the blade will tilt and the inner pipe will be cut at a larger angle.

[0008] Therefore, when cutting a composite pipe, the area around the holding protrusions should be avoided, but with the composite pipe of Patent Document 1, it was difficult to visually determine where the holding protrusions were. As a result, there was a risk that the pipe would be cut near the holding protrusions, resulting in the inner pipe being cut at an angle. If the end of the inner pipe is cut at a large angle, it will be necessary to re-cut it, so there was a need for a way to reduce this effort. [Means for solving the problem]

[0009] The present invention has been made to solve at least one of the above problems, and a corrugated cladding tube according to one aspect of the present invention comprises: A corrugated cladding tube covering a flexible inner tube, annular peaks and valleys alternately arranged in a tube axial direction; a plurality of retaining projections arranged at intervals in a tube axial direction, protruding radially inward from the valley portion, and retaining the inner tube substantially concentrically with the tube axis by their tips; Equipped with A recess corresponding to each of the holding projections is formed on the outer circumferential surface, When the inner tube is covered and the blade portion of a cutting tool is pressed perpendicularly to the tube axis against the center of the spacing in the tube axis direction of the recesses to cut the inner tube, the spacing of the holding protrusions in the tube axis direction is set so that the holding protrusions do not interfere with the blade portion.

[0010] According to the above-mentioned configuration, the recesses formed on the outer peripheral surface of the corrugated cladding tube allow the positions of the retaining protrusions to be confirmed from the outside of the corrugated cladding tube, and the cutting can be performed while avoiding the retaining protrusions. Furthermore, if the inner tube is cut in the center of the arrangement interval of the retaining protrusions in the tube axial direction while the inner tube is covered, the retaining protrusions do not interfere with the blade of the cutting tool, and therefore the inner tube can be prevented from being cut obliquely.

[0011] Preferably, when the cutting is performed, the pipe is supported by a pipe support portion of the cutting tool, and the spacing of the holding protrusions in the pipe axial direction is greater than the combined length of the width of the pipe support portion, the protruding length of the holding protrusion on one side of the pipe support portion, and the protruding length of the holding protrusion on the other side. According to the above configuration, the spacing between the holding protrusions in the pipe axial direction is greater than the combined width of the pipe support part of the cutting tool and the protruding length of the holding protrusions on both sides of it, so that the holding protrusions do not interfere with the blade portion of the cutting tool when cutting at the center of the spacing between the holding protrusions in the pipe axial direction.

[0012] Preferably, the holding projections are arranged at intervals of 50 mm to 70 mm in the axial direction of the tube.

[0013] Preferably, said retaining projections are circumferentially spaced apart. According to the above-mentioned configuration, the recesses formed on the outer peripheral surface corresponding to the respective holding protrusions are spaced apart in the circumferential direction, so that there are recesses and non-recessed portions in the circumferential direction, thereby improving the visibility of the recesses.

[0014] Preferably, the holding protrusion is provided in the valley portion, and a recess corresponding to this holding protrusion has a width greater than the width of the valley portion in the tube axial direction and is formed by cutting out a part of the peak portion. According to the above-mentioned configuration, the width of the recesses is larger than the width of the valleys, so that the valleys aligned in the tube axial direction cause a disturbance in appearance, thereby making it possible to improve the visibility of the recesses.

[0015] Preferably, the foam contains a foamed resin having an expansion ratio of 1.05 to 4 times. According to the above-mentioned configuration, the corrugated cladding tube is made of foamed resin, thereby improving flexibility. By setting the foaming ratio to 1.05 to 4 times, the flattening resistance is effectively reduced when the corrugated cladding tube is cut, and uneven crushing of the corrugated cladding tube can be prevented.

[0016] Preferably, the main component is low density polyethylene.

[0017] Another aspect of the present invention is a composite pipe including a flexible inner pipe and the corrugated cladding pipe that covers the inner pipe. Effect of the Invention

[0018] According to the present invention, when the corrugated cladding tube and the inner tube are cut simultaneously, the inner tube can be prevented from being cut obliquely. [Brief description of the drawings]

[0019] [Figure 1] 1 is a side view showing a cross section of only the upper half of a composite pipe including a corrugated cladding pipe according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged side view showing a main part of FIG. 1, with only the upper half being cross-sectionally shown. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a composite pipe connected to a joint. [Diagram 5] FIG. 2 is a perspective view showing a pipe cutter which is a cutting tool for composite pipes. [Figure 6] 2 is a plan view showing a state in which a composite pipe is supported by a pipe support portion of the pipe cutter and the blade portion is pressed against the pipe support portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a composite pipe 1 includes a flexible inner pipe 10 and a flexible corrugated sheathing pipe 20 (corrugated pipe) that covers the inner pipe 10. The composite pipe 1 is used as a pipe for supplying cold water or hot water, for example. The inside of the inner pipe 10 serves as a fluid passage through which fluids such as cold water and hot water pass.

[0021] The inner pipe 10 is formed with a constant circular cross section over its entire length and is flexible. As the inner pipe 10, a cross-linked polyethylene (PE-X) pipe, a polybutene (PB) pipe, a polyethylene (PE) pipe, a heat-resistant polyethylene (PE-RT) pipe, or a resin pipe containing two or more of these resins can be used. Also, a metal-reinforced resin pipe containing at least one of the above resin pipes and a metal can be used. Furthermore, the inner pipe 10 may be a multi-layer pipe containing multiple resin layers that are stacked without being tightly attached to each other. The above are merely examples, and there are no particular limitations on the material of the inner tube 10 as long as it can ensure the required performance such as flexibility and fluid flowability.

[0022] The corrugated cladding pipe 20 is made of a single-layered resin pipe, and may be a polyethylene (PE) pipe, a cross-linked polyethylene (PE-X) pipe, a polybutene (PB) pipe, a heat-resistant polyethylene (PE-RT) pipe, or a resin pipe containing two or more of these resins. The flexibility of the cladding pipe 20 may be improved by foaming. In this case, it is preferable to use polyethylene (PE) as the main component and to use a low foaming ratio of 1.05 to 4 times, and more preferably, the foaming ratio is 1.2 to 2.5 times. This effectively reduces the flattening resistance when cutting, and prevents the corrugated cladding pipe 20 from being crushed unevenly. More preferably, it is easier to increase the flexibility by using low-density polyethylene as the main component. The above are merely examples, and there are no particular limitations on the material of the corrugated cladding tube 20 as long as it can ensure the required performance such as flexibility and protection for the inner tube 10.

[0023] 1 and 2, the corrugated cladding tube 20 has a corrugated cross section formed by alternately arranging annular peaks 21 and annular valleys 22 in the tube axial direction. As shown in Fig. 2, the peaks 21 are short cylindrical with a constant diameter, and the cross section of the valleys 22 along the tube axial direction is U-shaped or V-shaped. The inner diameter of the valleys 22 may be larger than the outer diameter of the inner tube 10 by more than 2 mm, and may be in a state where so-called ringing noise may occur.

[0024] The corrugated cladding tube 20 further has holding protrusions 23 that are distributed in the tube axial direction and the circumferential direction and are independent of each other. In this embodiment, the holding protrusions 23 are provided in the valley portions 22, but they may be provided in the peak portions 21. The holding protrusions 23 are formed at equal intervals D in the tube axial direction, with four holding protrusions 23 being formed at equal intervals in the circumferential direction, as shown in Fig. 3.

[0025] The holding projection 23 protrudes radially inward beyond the valley portion 22 and has a protruding length L. The tip portion 230 of the holding projection 23 contacts the outer periphery of the inner pipe 10 or faces it at a small distance, thereby holding the inner pipe 10 substantially concentric with the pipe axis of the corrugated cladding pipe 20.

[0026] The corrugated cladding pipe 20 can suppress flapping of the inner pipe 10 and suppress noise by the retaining protrusions 23 concentrically retaining the inner pipe 10. In addition, the air insulation layer 24 formed between the corrugated cladding pipe 20 and the inner pipe 10 can improve heat retention. In this embodiment, the retaining protrusions 23 are distributed in the circumferential direction, so that the air insulation layer 24 is continuous without interruption over the entire area of ​​the composite pipe 1 in the axial direction. Therefore, the heat retention of the composite pipe 1 is improved, and the heat retention of fluids such as water and hot water flowing through the inner pipe 10 of this composite pipe 1 is improved.

[0027] In order to effectively improve the thermal insulation of the composite pipe 1, the protruding length L of the retaining protrusion 23 may be set so that a radial gap with an average value of 4 mm or more is formed between the inner surface of the valley portion 22 of the corrugated cladding pipe 20 and the outer surface of the inner pipe 10. In addition, since the holding protrusions 23 are distributed in the circumferential direction, the risk of structures getting caught can be reduced, making it easier to insert the inner pipe 10 into the corrugated cladding pipe 20. Furthermore, since the holding protrusions 23 are distributed in the axial direction of the pipe, they do not affect the flexibility in the axial direction of the pipe.

[0028] As shown in Fig. 1 and Fig. 2, recesses 25 corresponding to the holding protrusions 23 are formed on the outer peripheral surface of the corrugated cladding tube 20 so as to be recessed radially inward. As shown in Fig. 2, the recesses 25 have a width Wc in the tube axial direction that is larger than the width Wv of the valley portions 22, and are formed by cutting away parts of the peak portions 21. Since the width Wc of the recesses 25 is larger than the width Wv of the valley portions (Wc>Wv), the appearance of the valley portions 22 aligned in the tube axial direction is disturbed. This improves the visibility of the recesses 25. The width Wc of the recesses 25 may be set to 110% or more of the width Wv of the valley portions 22.

[0029] In addition, in this embodiment, since the holding protrusions 23 are arranged at intervals in the circumferential direction, the recesses 25 on the outer circumferential surface of the corrugated cladding tube 80 are also arranged at intervals in the circumferential direction. As a result, since there are recesses 25 and parts that are not recesses 25 in the circumferential direction, the visibility of the recesses 25 can be improved.

[0030] The connection of the compound pipe 1 to the joint 30 will now be described. As shown in FIG. 4, the composite pipe 1 is connected to a joint 30 by shrinking the corrugated cladding pipe 20 at one end in the axial direction to expose the inner pipe 10 and inserting it into the joint 30 . The joint 30 has a joint body 31 , an outer tube 32 , a water-stopping rubber ring 33 , a cap nut 34 , a retaining member 35 , a compression ring 36 , and a jumper pin 37 .

[0031] The joint body 31 is cylindrical and has a fluid flow path 31a formed therein. A first connection part 31b that is connected to a header or a pipe is provided at one end of the joint body 31. A second connection part 31c that is connected to the inner pipe 10 is provided at the other end of the joint body 31.

[0032] An outer tube 32 is provided on the outer periphery of the second connecting part 31c. The outer tube 32 is connected to the base end of the second connecting part 31c so as to form an annular receiving part 31d between the outer tube 32 and the second connecting part 31c. Two rows of water-stopping rubber rings 33 are provided as a sealing member on the outer surface of the second connecting part 31c within the receiving part 31d.

[0033] A cap nut 34 is attached to the tip of the outer tube 32. An annular retaining member 35 is fixed with its outer periphery sandwiched between the tip surface of the outer tube 32 and the inner bottom surface of the cap nut 34. The retaining member 35 allows the inner tube 10 to be inserted into the receiving portion 31d, but prevents the inner tube 10 from being pulled out of the receiving portion 31d.

[0034] A compression ring 36 capable of expanding and contracting in diameter is provided in the receiving portion 31d on the rear side of the retaining member 35. The compression ring 36 is previously expanded by the jumper pin 37, and then narrowed in the radial direction by the tip of the inner tube 10 pushing the jumper pin 37 to the rear and removing it. As a result, the compression ring 36 tightens the inner tube 10, and the inner tube 10 is brought into close contact with the water-stopping rubber ring 33.

[0035] In this manner, the composite pipe 1 is connected to the joint 30. At this time, the end of the corrugated cladding pipe 20 in the contracted state is in close contact with the tip portion of the cap nut .

[0036] When connecting the composite pipe 1 to the fitting 30 as described above, a manual cutting tool such as a pipe cutter 40 shown in Figure 5 can be used to cut the composite pipe 1 to a predetermined length and make the cut surface of the inner pipe 10 flat.

[0037] 5, the pipe cutter 40 has a pair of operating pieces 41, 42. The operating pieces 41, 42 are connected to be rotatable openable and closable by a rotating shaft 43, and have handles 41a, 42a, respectively, at their base ends, and a blade portion 44 and a pipe support portion 45, respectively, at their tip ends.

[0038] The pipe support part 45 is formed in a U-shape when viewed from the axial direction of the rotating shaft 43. The composite pipe 1 is placed and supported on the pipe support part 45, as shown in Fig. 6, with the short side direction of the operating piece 42 being the pipe axis direction. The pipe support part 45 has a short side width Ws capable of supporting the composite pipe 1. A blade receiving groove 45a wider than the thickness of the blade portion 44 is formed in the middle part of the pipe support part 45 in the width Ws direction, so that the blade portion 44 can be inserted up to the bottom of the pipe support part 45.

[0039] Cutting of the compound pipe 1 using the pipe cutter 40 will now be described. First, the composite pipe 1 is grasped with one hand, and the pair of handles 41a, 42a are gripped with the other hand to open the blade portion 44 and the pipe support portion 45. Then, as shown in Fig. 6, the composite pipe 1 is placed and supported on the pipe support portion 45, and the composite pipe 1 is clamped between the blade portion 44 and the pipe support portion 45. At this time, the blade portion 44 is pressed against the composite pipe 1 perpendicular to its pipe axis. Next, when the handles 41a, 42a are gripped to close the blade portion 44 and the pipe support portion 45, the composite pipe 1 including the corrugated cladding pipe 20 and the inner pipe 10 is cut.

[0040] If the holding protrusions 23 of the corrugated cladding pipe 20 are located near the blade portion 44 during cutting, the corrugated cladding pipe 20 may be crushed unevenly, the corrugated cladding pipe 20 may not be concentric with the inner pipe 10, and the inner pipe 10 may be cut at an angle. In particular, if the holding protrusions 23 interfere with the blade portion 44, the inner pipe 10 may be cut at a large angle. If the tip of the inner pipe 10 is cut at an angle, the water-stopping surface between the inner pipe 10 and the water-stopping rubber ring 33 in the joint 30 may not be stable when the composite pipe 1 and the joint 30 are connected as described above, which may cause problems such as water leakage.

[0041] Therefore, the arrangement interval D of the holding projections 23 in the tube axial direction must be set so as to prevent the inner tube 10 from being obliquely cut, and can be set as follows. The interval D may be set to be larger than the combined length of the width Ws of the pipe support portion 45 of the pipe cutter 40, the protruding length L of the holding protrusion 23, and the protruding length L of another holding protrusion 23 located immediately adjacent to this holding protrusion 23 on one side in the pipe axial direction (D>Ws+2L). In this case, if the cutting is performed at the center of the interval D, interference between the holding protrusion 23 and the blade portion 44 and uneven crushing of the corrugated cladding pipe 20 can be avoided.

[0042] In addition, the above-mentioned arrangement distance D may be set by providing an allowance (not shown, but for ease of explanation, designated by the symbol P) for when the blade portion 44 deviates from the center of the distance D in the tube axial direction during cutting (D>Ws+2L+P).

[0043] According to the above embodiment, the recesses 25 corresponding to the holding protrusions 23 can be seen from the outside, and this allows the compound pipe 1 to be cut while avoiding the holding protrusions 23. The installation interval D of the holding protrusions 23 is set so that the holding protrusions 23 do not affect the cutting, and this prevents the inner pipe 10 from being cut at an angle. This reduces the effort required to recut the compound pipe 1 due to the inner pipe 10 being cut at an angle.

[0044] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. In the above embodiment, four holding protrusions 23 are provided distributed in the circumferential direction of the corrugated cladding tube 20, but the number may be five or more or less than four, or one holding protrusion may be provided over the entire circumference. EXAMPLES

[0045] The following examples are provided to illustrate, but are not intended to limit the scope of the present invention. When the pipe cutter 40 does not include a marking function, the width Ws of the pipe support portion 45 is generally around 20 mm, and often at most about 30 mm. The holding projections 23 project radially inward with a protruding length L of 5 mm. In this case, if the arrangement interval D of the holding projections 23 in the pipe axial direction is 50 mm, interference between the blade portion 44 of the pipe cutter 40 and the holding projections 23 can be avoided when the composite pipe 1 is cut at the center of the interval D. This can effectively prevent the inner pipe 10 from being cut obliquely by the blade portion 44, which may occur in the event of interference.

[0046] When the arrangement interval D is set to 50 mm, if the allowable margin P for each deviation of the blade portion 44 from the center of the interval D to one side or the other in the pipe axial direction when cutting the compound pipe 1 is set to 10 mm, the arrangement interval D becomes 70 mm. Therefore, in this embodiment, the arrangement interval D is set to 50 mm to 70 mm. It is preferable to use a large pipe cutter 40 with a long blade portion 44 so that the corrugated cladding pipe 20 can be cut in one go even if the corrugated cladding pipe 20 is crushed during cutting. [Industrial Applicability]

[0047] The present invention can be applied to a corrugated cladding pipe that is fitted over a flexible inner pipe suitable for transporting a fluid, and to a compound pipe that includes this corrugated cladding pipe and an inner pipe. [Explanation of symbols]

[0048] 1 Composite pipe 10 Inner tube 20 Corrugated cladding 21 Yamabe 22 Valley 23 Retaining protrusion 25 Recess 30 Joints 40 Pipe cutter (cutting tool) 44 Blade 45 Pipe support part D Spacing of retaining protrusions L Protruding length of the retaining protrusion Ws Width of tube support Wv Width of valley Wc Recess width

Claims

1. A corrugated cladding tube covering a flexible inner tube, annular peaks and valleys alternately arranged in a tube axial direction; a plurality of retaining projections arranged at intervals in a tube axial direction, protruding radially inward from the valley portion, and retaining the inner tube substantially concentrically with the tube axis by their tips; Equipped with A recess corresponding to each of the holding projections is formed on the outer circumferential surface, a corrugated coated pipe, characterized in that, when the inner pipe is covered and the blade portion of a cutting tool is pressed against the center of the spacing in the axial direction of the recesses perpendicular to the pipe axis to cut the inner pipe, the spacing of the holding protrusions in the axial direction of the pipe is set so that the holding protrusions do not interfere with the blade portion.

2. When the cutting is performed, the pipe is supported by a pipe support part of the cutting tool, 2. The corrugated clad tube according to claim 1, characterized in that the spacing between the retaining protrusions in the tube axial direction is greater than the combined length of the width of the tube support portion, the protruding length of the retaining protrusion on one side of the tube support portion, and the protruding length of the retaining protrusion on the other side of the tube support portion.

3. 3. The corrugated cladding tube according to claim 1, wherein the intervals of the holding projections in the axial direction of the tube are 50 mm to 70 mm.

4. 3. The corrugated cladding tube according to claim 1, wherein the retaining projections are arranged at intervals in the circumferential direction.

5. The holding protrusion is provided in the valley portion, 3. The corrugated cladding tube according to claim 1, wherein the recesses corresponding to the holding protrusions have a width greater than a width of the root portions in the axial direction of the tube and are formed by cutting out a part of the peak portions.

6. 3. The corrugated cladding tube according to claim 1, further comprising a foamed resin having a foaming ratio of 1.05 to 4.

7. 3. The corrugated cladding tube according to claim 1, characterized in that it is mainly composed of low density polyethylene.

8. A composite pipe comprising: a flexible inner pipe; and the corrugated cladding pipe according to claim 1 or 2 that covers the inner pipe.

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