Piping system

Abstract

To provide a piping system capable of improving workability.SOLUTION: A piping system 100 includes a joint 10 having a connection port 11, a pipe 20 connected to the connection port 11, and a cover 30 covering an outer peripheral surface of the joint 10 and an outer peripheral surface of the pipe 20 along a circumferential direction, wherein a circumferential first concave portion 13 is provided on the outer peripheral surface of the joint 10, a circumferential second concave portion 23 is provided on the outer peripheral surface of the pipe 20, and the cover 30 includes a first convex 31A fitted to the first concave portion 13 and a second convex 31B fitted to the second concave portion 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a piping system. [Background technology]

[0002] A known joint uses a clamp to secure the joint to a pipe when connecting the joint to the pipe. For example, Patent Document 1 discloses that the clamp is integrally formed with the joint and clamps the joint to the pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-31840 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, when fixing the fitting and the pipe, it is necessary to tighten the clamp part. Tightening the clamp part requires a fastening operation using a screw or the like. Fastening operation using a clamp part may cause variations in the fitting force depending on the installer, and installation work is difficult in a small space. As such, there is room for improvement in installation work using a clamp part.

[0005] In view of the above-mentioned circumstances, the present disclosure aims to provide a piping system that enables improved workability. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following aspects. <1> A piping system according to one embodiment of the present invention includes: a fitting having a connection port; A pipe connected to the connection port; a cover that covers an outer peripheral surface of the joint and an outer peripheral surface of the pipe along a circumferential direction; Equipped with a first circumferential recess is provided on the outer peripheral surface of the joint; a second circumferential recess is provided on the outer peripheral surface of the pipe; The cover includes a first protrusion that fits into the first recess, and a second protrusion that fits into the second recess. <2> The aforementioned <1> In the piping system described in , the first protrusion and the second protrusion of the cover may include protrusions that protrude in the longitudinal direction of the piping system. <3> The aforementioned <1> or <2> In the piping system described in 1, a length between the first convex portion and the second convex portion of the cover may be equal to or less than a distance between the first recessed portion and the second recessed portion. <4> The aforementioned <1> In the piping system described above, the joint may be an electrofusion joint. <5> The aforementioned <4> The piping system described in A terminal is provided on the outer peripheral surface of the electric fusion joint, The first recess may be formed in the circumferential direction so as to avoid the terminal. <6> The aforementioned <4> or <5> The piping system described in an indicator is provided on the outer peripheral surface of the electric fusion joint; The first recess may be formed in the circumferential direction so as to avoid the indicator. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to achieve the effect of improving workability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a piping system according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of the piping system shown in FIG. [Figure 3] FIG. 2 is a plan view of the joint shown in FIG. [Figure 4]FIG. 2 is a plan view of the piping shown in FIG. [Figure 5] FIG. 3 is a cross-sectional view taken along the arrows VV in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. [Figure 7] FIG. 2 is a plan view of the cover shown in FIG. [Figure 8] FIG. 4 is a partial cross-sectional view showing a piping system according to a second embodiment of the present disclosure. [Figure 9] FIG. 9 is a plan view of the joints and the like shown in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment Hereinafter, a piping system according to a first embodiment of the present disclosure will be described with reference to FIGS. FIG. 1 is a perspective view showing a piping system 100 according to a first embodiment. FIG. 2 is a plan view of the piping system 100 shown in FIG. 1. As shown in FIGS. 1 and 2, the piping system 100 includes a joint 10, a pipe 20, and a cover 30. In this embodiment, as shown in FIGS. 1 and 2, the piping system 100 is configured such that the pipe 20 is connected to one end of the joint 10 along the longitudinal direction of the piping system 100. Alternatively, the piping system 100 may be configured such that the pipe 20 is connected to both ends of the joint 10 along the longitudinal direction of the piping system 100.

[0010] As shown in FIG. 3, the fitting 10 has a fitting body 12 and a connection port (first connection port) 11 provided at an end in the axial direction, which is the direction in which the central axis of the fitting 10 extends. In this embodiment, the first connection port 11 is provided at both ends of the fitting body 12. The first connection port 11 may also be provided at one end of the fitting body 12. In this embodiment, the first connection port 11 of the fitting 10 serves as a socket into which a pipe, described below, is inserted. The fitting 10 is formed in a hollow cylindrical shape. The central axes of the joint 10 and the piping 20 and cover 30 (described later) are arranged coaxially with a common axis. In this embodiment, this common axis is referred to as an axis O1. The axis O1 is the axis of the piping system 100. The direction perpendicular to the axis O1 is called the radial direction, and the direction going around the axis O1 is called the circumferential direction. The shape of the joint 10 is not limited to a hollow cylindrical shape, but may be a square cylindrical shape or the like. Examples of methods for forming the joint 10 include extrusion molding and injection molding. In particular, extrusion molding makes it easy to form the joint 10 into a long shape or with a large diameter.

[0011] The joint 10 is made of, for example, a thermoplastic resin. As the thermoplastic resin, it is preferable to use a polyolefin resin similar to that of the pipe 20 described later.

[0012] As shown in Figures 1 and 2, the pipe 20 is connected to the first connection port 11 of the fitting 10. As shown in Figure 4, the pipe 20 has a pipe main body 22 provided at one end side in the direction of the axis O1, and a connection port (second connection port) 21 provided at the other end side. The second connection port 21 of the pipe 20 is connected to the first connection port 11 of the fitting 10. The pipe main body 22 of the pipe 20 is formed in a hollow cylindrical shape. In this embodiment, the second connection port 21 is a spigot port. The second connection port 21 extends outward in the direction of the axis O1 from the end of the piping main body 22 in the direction of the axis O1. The second connection port 21 is a hollow cylinder coaxial with the piping main body 22. The outer diameter of the second connection port 21 is smaller than the outer diameter of the piping main body 22. The inner circumferential surface of the second connection port 21 is continuous with the inner circumferential surface of the piping main body 22. Note that the second connection port 21 and the piping main body 22 may be butt-welded (welded in a butted state), in which case, a circumferentially extending protrusion (so-called bead) may be provided on each of the inner circumferential surface and outer circumferential surface between them. The end of the piping body 22 on the second connection port 21 side in the axis O1 direction is a stopper portion 22a radially outward from the second connection port 21. The end face of the stopper portion 22a on the second connection port 21 side in the axis O1 direction of the piping body 22 is flat and extends perpendicular to the axis O1 of the piping body 22 and the second connection port 21.

[0013] The second connection port 21 of the pipe 20 is inserted radially inside the first connection port 11 of the fitting 10. Therefore, the fitting body 12 of the fitting 10 has a length and an inner diameter that allow the second connection port 21 of the pipe 20 to be inserted a required length. The second connection port 21 of one of the mating pipes 20 may be inserted into one end (first connection port 11) of the fitting 10, and the second connection port 21 of the other of the mating pipes 20 may be inserted into the other end (first connection port 11) of the fitting 10. In the fitting 10, the side into which the second connection port 21 of one of the pipes 20 is inserted is one first connection port 11, and the side into which the second connection port 21 of the other pipe 20 is inserted is the other first connection port 11. In this way, the pipe 20 has first connection ports 11 at both longitudinal ends. 1 and 2 show a state in which the second connection port 21 of the pipe 20 is inserted into the first connection port 11 on only one side in the longitudinal direction.

[0014] A stopper portion 22a is provided at the end of the piping body 22 on the second connection port 21 side in the direction of the axis O1. The stopper portion 22a can abut against the end of the first connection port 11 of the fitting 10 in the direction of the axis O1 when the second connection port 21 is inserted.

[0015] The outer diameter of fitting 10 may be equal to the outer diameter of pipe body 22 of pipe 20. Of course, the outer diameter of either fitting 10 or pipe 20 may be larger by several millimeters. As shown in FIG. 2, the outer diameter of fitting 10 may be slightly smaller than the outer diameter of pipe 20.

[0016] The pipe 20 is preferably made of a thermoplastic resin such as a polyolefin-based resin. The polyolefin-based resin pipe 20 has a higher tensile breaking elongation measured in accordance with JIS K 6815-1 and JIS K 6815-3 than a rigid polyvinyl chloride pipe. While the tensile breaking elongation of a rigid polyvinyl chloride pipe is 50 to 150%, the tensile breaking elongation of a polyolefin-based resin pipe is 350% or more. In particular, by the extrapolation method specified in ISO / TR9080, a PE100 high-density polyethylene pipe has a tensile breaking elongation of 500% or more, which can better prevent damage caused by earthquakes.

[0017] The polyolefin resin is not particularly limited, but suitable examples include polyethylene, polypropylene, polybutene, atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, poly-α-olefin, etc. Among these, it is desirable to use polyethylene from the viewpoint of strength, etc. When selecting polyethylene, it is desirable to appropriately select any of low-density polyethylene, medium-density polyethylene, high-density polyethylene, etc. depending on the durability desired for the pipe 20. A pipe 20 made of polyethylene resin can be used from the viewpoint of not affecting earthquake resistance, durability, water quality, etc. In particular, when the pipe 20 is used as a drinking water pipe, a high-density polyethylene resin pipe is preferable.

[0018] The specific gravity of the thermoplastic resin is not particularly limited, but is, for example, 942 to 953 kg / m3. The specific heat of the thermoplastic resin is not particularly limited, but is, for example, 1.9 to 2.3 kJ / kg [K]. The thermal conductivity of the thermoplastic resin is not particularly limited, but is, for example, 0.46 to 0.5 W / m K. The thermoplastic resin may be a composition containing additives such as pigments, ultraviolet absorbers, antioxidants, and lubricants. The melting point of the thermoplastic resin (ie, the melting temperature of the pipe 20) is not particularly limited, but is preferably 125 to 260°C, and more preferably 125 to 150°C.

[0019] The pipe 20 may have a multi-layer structure having a surface layer on at least one of the outer circumferential surface and the inner circumferential surface. For example, by having a surface layer containing an ethylene-vinyl alcohol copolymer resin, the pipe 20 may be a pipe for any purpose, such as a drinking water pipe, a gas pipe, or a sewer pipe, because the surface layer containing an ethylene-vinyl alcohol copolymer resin makes it difficult for gases such as hydrogen, oxygen, propane, and butane, and hydrocarbons such as gasoline and benzene, to permeate.

[0020] The surface layer may contain, for example, at least one of inorganic fibers and organic fibers. Examples of inorganic fibers include glass fibers, carbon fibers, silicon-titanium-carbon composite fibers, boron fibers, and metal fibers. Examples of organic fibers include aramid fibers, vinylon fibers, polyester fibers, and polyamide fibers. When the surface layer contains these fibers, the tensile strength of the pipe 20 can be increased and thermal expansion can be further suppressed. The surface layer may also contain a fluororesin. When the surface layer contains fluorine, resistance (chemical resistance) to acids, alkalis, and the like can be improved. Furthermore, a layer similar to the above surface layer may be provided inside the wall of the pipe 20.

[0021] The SDR value, which is the ratio of the outer diameter D to the wall thickness T of the pipe 20, is preferably 13.5 or less. If the SDR value exceeds 13.5, the pipe wall becomes too thin and may not be able to withstand the internal pressure of the fluid when the fluid flows inside. If the SDR value is too low, the pipe wall may become too thick and may not be able to ensure a sufficient flow rate. For this reason, the lower limit of the SDR value is preferably 6 or more, and more preferably 7.4 or more.

[0022] Generally, in pipe thickness design, for pipes with water flowing inside, the relationship that follows the Naday equation shown in equation (1) below is known to represent the tensile circumferential stress (tensile stress generated in the circumferential direction in the cross section of the pipe) generated in the pipe due to the internal water pressure. σ=P(Dt) / 2t …(1) formula In equation (1), σ is the tensile circumferential stress generated in the pipe (MPa), P is the internal water pressure (MPa), D is the outer diameter of the pipe (mm), and t is the thickness of the pipe (mm).

[0023] Based on the Naday equation mentioned above, it is preferable to design the pipe thickness so that the stress generated at the design internal pressure (maximum allowable stress) has a safety factor of 2 for the 50-year creep strength of polyethylene water distribution pipes. For example, this relationship can be expressed by the following equation (2). σ50 / S1=Pd(Dt) / 2t …(2) formula In equation (2), σ50 is the 50-year creep strength of polyethylene water distribution pipe (10 MPa), S1 is the safety factor for σ50 (assumed to be 2 here), and Pd is the maximum allowable pressure (hydrostatic pressure 0.75 × water hammer pressure 0.25 = 1.0 PMa). By modifying the above equation (2), the value of SDR (Standard Dimension Ratio) can be calculated using the following equation (3). SDR=D / t=1+(2σ50) / Pd·S1=1+(2×10) / (1×2)=11…(3) formula

[0024] According to the pipe thickness design for water pipes, which was calculated with the aforementioned safety factor of 2, it is clear that an SDR value of 11 is preferable, but if the purpose is to rehabilitate pipes such as polyethylene sewer pipes, where the internal pressure of the pipe can be estimated to be low, an SDR value of 13.5 or less is desirable. Furthermore, if the standard SDR value for polyethylene water pipes is 11, the SDR value will be less than SDR6 when the flow rate drops by 40% (calculated based on a flow velocity coefficient of 140 and a hydraulic gradient of 3%), so an SDR value of 6 or more is preferable.

[0025] The piping 20 is a pipe housed inside the existing piping 1, but is a self-supporting pipe, unlike the thin, non-self-supporting pipes with inner linings used in conventional technology. Moreover, it is preferable that the piping 20 be a resin pipe with little deformation and an ovality of 4.5 mm or less. The measurement method for the ovality of the pipe 20 should preferably comply with the Japan Water Works Association standard: JWWAK144 (polyethylene pipe for water distribution). Measure each dimension of the resin pipe at 23±2°C with a measuring device such as a vernier caliper 24 hours or more after its manufacture, and allow it to condition for at least four hours before measurement. Furthermore, if the temperature measurement is outside of 23±2°C, such as when measuring dimensions outdoors, it is desirable to convert the measurement value to a dimension at 23°C using the following formula (4).

[0026] L23={1+α×(23-t)}×Lt…(4) formula In equation (4), L23 is the dimension at 23°C (converted value), α is the linear expansion coefficient (1 / °C) (polyethylene pipe for water distribution: 12.0 × 10-5), t is the temperature at the time of measurement (°C), and Lt is the dimension at t°C (measured value). For example, in equation (4), if the outer diameter of a straight pipe with a nominal diameter of 100 is measured at an air temperature of 35°C (the temperature of the resin pipe is also 35°C) and the measured value is 125.9 mm, the converted value at 23°C will be 125.7 mm as calculated by the following formula. D23={1+12.0×10-5×(23-35)}×125.9=125.7mm

[0027] The piping 20 used in this embodiment preferably has a deflection rate of 5% or less. The deflection rate is preferably measured in accordance with the Japan Water Works Association standard: JWWA K144 (polyethylene pipe for water distribution).

[0028] The cover 30 covers the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20 in the circumferential direction. Specifically, as shown in FIG. 6 , when the pipe 20 is inserted into the fitting 10, that is, when the stopper portion 22a of the pipe 20 abuts against the end of the first connection port 11 of the fitting 10, the cover 30 covers the outer peripheral surface of the first connection port 11 of the fitting 10 and the outer peripheral surface of the pipe main body 22 of the pipe 20 in the circumferential direction. As shown in FIG. 5 , the cover 30 has a curved shape when viewed from the direction of the axis O1. When viewed from the arrow in FIG. 5 , the cover 30 is not a circular shape formed continuously all the way around, but is C-shaped. In this way, the cover 30 covers the outer peripheral surface of the fitting 10 and a portion of the outer peripheral surface of the pipe 20 in the circumferential direction.

[0029] A circumferential first recess 13 is provided on the outer peripheral surface of the joint 10. As shown in Figure 3, the first recess 13 is formed in the circumferential direction on the outer peripheral surface of the end 14 of the joint body 12. The first recess 13 may be formed over the entire outer peripheral surface of the end 14 of the joint body 12, or may be formed on a portion of the outer peripheral surface. In the example shown in Figure 3, the first recess 13 is formed on a portion of the outer peripheral surface of the end 14 of the joint body 12. The first recess 13 is preferably disposed in a location that does not affect the performance of the joint 10 when pressure is applied to the inside of the pipe 20 and the joint 10 .

[0030] A circumferential second recess 23 is provided on the outer peripheral surface of the pipe 20. As shown in FIG. 4, the second recess 23 is formed in the circumferential direction on the outer peripheral surface of the end 24 of the pipe 20. The end 24 of the pipe 20 is the end on the stopper portion 22a side of the pipe main body 22 in the direction of the axis O1. The second recess 23 may be formed over the entire outer peripheral surface of the end 24 of the pipe 20, or may be formed on a part of the outer peripheral surface. In the example shown in FIG. 4, the second recess 23 is formed on a part of the outer peripheral surface of the end 24 of the pipe 20.

[0031] 7 (plan view of the cover 30), the cover 30 has protrusions 31 that protrude inward (radially inward) from both ends of the cover body 32. The cross section of the cover 30 is generally U-shaped when viewed from the arrow in FIG. 7. These protrusions 31 fit into the first recess 13 and the second recess 23. In detail, the cover 30 has a first protrusion 31A that fits into the first recess 13 of the fitting 10 and a second protrusion 31B that fits into the second recess 23 of the pipe 20. 6, when the piping 20 is inserted into the fitting 10, that is, when the stopper portion 22a of the piping 20 is in contact with the end of the first connection port 11 of the fitting 10, the first convex portion 31A and the second convex portion 31B of the cover 30 fit into the first recess 13 of the fitting 10 and the second recess 23 of the piping 20, respectively. As a result, the cover 30 serves to fix the fitting 10 and the piping 20 so that they do not come off in the direction of the axis O1. The cover body 32 may be curved on the side of the first protrusion 31A when viewed in the direction of the arrow in FIG.

[0032] It is desirable that the first protrusion 31A and the second protrusion 31B are configured to reliably fit into the first recess 13 of the joint 10 and the second recess 23 of the pipe 20, respectively. For example, it is desirable to set the heights of the first convex portion 31A and the second convex portion 31B appropriately so that the joint 10 and the pipe 20 do not come off. For example, the height 31Ah of the first protrusion 31A that fits into the first recess 13 of the fitting 10 is preferably 3 mm or more and 5 mm or less. If the height 31Ah of the first protrusion 31A is less than 3 mm, the area over which the first protrusion 31A fits into the first recess 13 of the fitting 10 is small, which may cause the fitting 10 and the piping 20 to easily come apart. In addition, the catch portion of the first protrusion 37A, which will be described later, becomes small, which may reduce the fitting force. If the height 31Ah of the first protrusion 31A exceeds 5 mm, the first recess 13 of the fitting 10 must also be formed deep to match the height 31Ah of the first protrusion 31A, which may affect the strength of the fitting 10, and is therefore undesirable. The height 31Ah of the first protrusion 31A is the distance (mm) from the lower surface of the cover body 32 to the tip of the first protrusion 31A at the end of the cover body 32 when viewed from the arrow in FIG.

[0033] Furthermore, for example, the height 31Bh of the second protrusion 31B that fits into the second recess 23 of the pipe 20 is preferably 3 mm or more and 5 mm or less. If the height 31Bh of the second protrusion 31B is less than 3 mm, the area over which the second protrusion 31B fits into the second recess 23 of the pipe 20 becomes small, which may cause the fitting 10 and the pipe 20 to easily come apart. Also, the catch portion of the second protrusion 37B, which will be described later, becomes small, which may reduce the fitting force. If the height 31Bh of the second protrusion 31B exceeds 5 mm, the second recess 23 of the pipe 20 must also be formed deep to match the height 31Bh of the second protrusion 31B, which may affect the strength of the pipe 20, and is therefore undesirable. The height 31Bh of the second protrusion 31B is the distance (mm) from the lower surface of the cover body 32 to the tip of the second protrusion 31B at the end of the cover body 32 when viewed from the arrow in FIG.

[0034] The width 31Aw (mm) of the first protrusion 31A and the width 31Bw (mm) of the second protrusion 31B are, for example, equal to the thickness of the cover 30. The width 31Aw of the first protrusion 31A and the width 31Bw of the second protrusion 31B do not have to be equal to the thickness of the cover 30 and may be thicker than the thickness of the cover 30. The width 31Aw of the first protrusion 31A and the width 31Bw of the second protrusion 31B are the thicknesses of the first protrusion 31A and the second protrusion 31B, respectively, when viewed in the direction of the arrow in FIG.

[0035] The depth 13h (mm) and width 13w (mm) of the first recess 13 of the joint 10 may be set in consideration of the height 31Ah and width 31Aw of the first protrusion 31A of the cover 30. The depth 23h (mm) and width 23w (mm) of the second recess 23 of the pipe 20 may be set taking into consideration the height 31Bh and width 31Bw of the second protrusion 31B of the cover 30. At this time, it is necessary to consider that if the depth 13h of the first recess 13 or the depth 23h of the second recess 23 is too deep, or if the width 13w of the first recess 13 or the width 23w of the second recess 23 is too wide, this may affect the performance of the fitting 10 itself. Because the first recess 13 or the second recess 23 expands slightly when the first protrusion 31A and the second protrusion 31B ride over the catch portion, the width 13w or the width 23w must be equal to or greater than the maximum value when expanded. Methods for measuring the height 31Ah and width 31Aw of the first convex portion 31A of the cover 30, the height 31Bh and width 31Bw of the second convex portion 31B of the cover 30, the depth 13w and width 13h of the first recess 13 of the fitting 10, and the depth 23w and width 23h of the second recess 23 of the piping 20 include, for example, measuring devices such as vernier calipers.

[0036] The cross-sectional shapes of the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 are, for example, angular, as shown in FIGS. 3 and 4 . The cross-sectional shapes of the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 may be, for example, U-shaped, V-shaped, or dovetail-shaped to fit a dovetail groove. A dovetail groove is a groove with a narrow entrance and a wide bottom cross-sectional shape that prevents the protrusion from slipping out. The entrance portion of the dovetail groove may be semicircular, so that the first protrusion 31A, the second protrusion 31B, and the first recess 13 or the second recess 23 are not damaged when the fitting is inserted or removed. Alternatively, only the entrance side may be rounded, and the return portion may be a vertical angular shape that prevents the protrusion from slipping out.

[0037] The first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 are formed as recesses (grooves) by, for example, lathe processing. Alternatively, the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 may be formed as recesses by injection molding.

[0038] The number of covers 30 covering the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20 does not need to be limited. One or more covers 30 may cover the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20 along the circumferential direction. For example, as shown in FIG. 5, two covers 30 may cover the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20. In this case, as shown in FIG. 5, arranging the two covers 30 symmetrically in the view of the arrow in the direction of the axis O1 can achieve balance and improve workability. The number of covers 30 covering the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20 may be three or more. As shown in FIG. 5, in the view of the arrow in FIG. 5 (view of the arrow in the direction of the axis O1), the angle θ1 (°) formed between the cover ends 33, 34 and the center point O of the cover 30 may be less than 180°. 5, the cover end 33 is the innermost end (closer to the center point O) of the protrusions 31 (first protrusion 31A, second protrusion 31B) at one end of the cover 30. The cover end 34 is the innermost end (closer to the center point O) of the protrusions 31 (first protrusion 31A, second protrusion 31B) at the other end of the cover 30. The angle θ1 is the angle (°) formed by a line O-33 connecting the center point O of the cover 30 to the cover end 33 and a line O-34 connecting the center point O of the cover 30 to the cover end 34. The center point O of the cover 30 is disposed as a common point between the centers of the joint 10 and the pipe 20, and passes through the axis O1.

[0039] The cover 30 can be made of a thermoplastic resin such as a polyvinyl chloride resin. Examples of polyvinyl chloride resins include polyvinyl chloride homopolymers, copolymers of vinyl chloride monomers with other monomers having unsaturated bonds copolymerizable with the vinyl chloride monomers, and graft copolymers in which vinyl chloride monomers are graft-copolymerized onto polymers other than polyvinyl chloride resins. The polyvinyl chloride resins may be used alone or in combination of two or more. When a resin such as a thermoplastic resin is used for the cover 30, the thickness of the cover 30 is, for example, 2 mm. When a resin such as a thermoplastic resin is used for the cover 30, the cover 30 is molded by, for example, injection molding or extrusion molding. A metallic material can also be used for the cover 30. An example of a metallic material is SS400. When a metallic material is used for the cover 30, the cover 30 is formed by, for example, press molding or cutting. When the cover 30 is made of a metal material, the thickness of the cover 30 is, for example, 0.5 mm.

[0040] The piping system 100 according to this embodiment is configured such that the cover 30 covers the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20 in the circumferential direction, and the first convex portion 31A and the second convex portion 31B of the cover 30 fit into the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20, respectively. This configuration eliminates the need for processes such as fastening with screws, and the fitting 10 and the pipe 20 can be easily fixed by fitting the cover 30 into the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20. Therefore, the piping system 100 according to this embodiment can improve workability.

[0041] The first protrusion 31A and the second protrusion 31B of the cover 30 preferably include protrusions 37 that protrude in the longitudinal direction (axis O1 direction) of the piping system 100. Specifically, in the view of the arrows in FIG. 7, the first protrusion 31A includes a first protrusion 37A that protrudes inward in the axis O1 direction, and the second protrusion 31B includes a second protrusion 37B that protrudes inward in the axis O1 direction. The first protrusion 37A and the second protrusion 37B protrude toward each other. The first protrusion 37A and the second protrusion 37B are provided at the tips of the first protrusion 31A and the second protrusion 31B, respectively. 7, the first protrusion 31A may include a first protrusion 37A that protrudes outward in the direction of the axis O1, and the second protrusion 31B may include a second protrusion 37B that protrudes outward in the direction of the axis O1. The first protrusion 37A and the second protrusion 37B may be provided around the entire circumferential direction of the cover 30.

[0042] The first recess 13 of the fitting 10 may be provided in the longitudinal direction of the piping system 100 to match the shape of the first protrusion 37A of the cover 30. The second recess 23 of the piping 20 may also be provided in the longitudinal direction of the piping system 100 to match the shape of the second protrusion 37B of the cover 30. 6, when the piping 20 is inserted into the fitting 10, that is, when the stopper portion 22a of the piping 20 is in contact with the end of the first connection port 11 of the fitting 10, the first protrusion 37A and the second protrusion 37B of the cover 30 fit into and press the first recess 13 of the fitting 10 and the second recess 23 of the piping 20, respectively. This enables the cover 30 to better fix the fitting 10 and the piping 20 so that they do not come off in the direction of the axis O1.

[0043] In the piping system 100 according to this embodiment, the first protrusion 31A and the second protrusion 31B of the cover 30 are configured to include protrusions 37 that protrude in the longitudinal direction of the piping system 100. With this configuration, the fitting 10 and the piping 20 can be fixed with an improved fitting force.

[0044] The mating force between the cover 30 and the fitting 10 and the pipe 20 depends on the relationship between the width 32w (mm) of the cover body 32 and the separation width (separation length) 40w (mm) between the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 when the pipe 20 is inserted into the fitting 10 (when the stopper portion 22a of the pipe 20 is abutting against the end of the first connection port 11 of the fitting 10). Specifically, when the width 32w of the cover body 32 is equal to or less than the separation width 40w between the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20, the mating force between the cover 30 and the fitting 10 and the pipe 20 can be improved. The mating force can be further improved by setting the width 32w of the cover body 32 to 0.95 or less of the separation width 40w. The width 32w of the cover body 32 is the length between the first protrusion 31A and the second protrusion 31B when viewed from the arrow in FIG. 7 . The separation width 40w between the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20 is the length between the end face 13a of the first recess 13 and the end face 23a of the second recess 23 when the pipe 20 is inserted into the fitting 10 (when the stopper portion 22a of the pipe 20 is in contact with the end of the first connection port 11 of the fitting 10). The end face 13a is the surface of the first recess 13 on the side to which the pipe 20 is connected. The end face 23a is the surface of the second recess 23 on the side to which the fitting 10 is connected.

[0045] Second Embodiment A piping system according to a second embodiment of the present disclosure will be described below with reference to Figures 8 and 9. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted, with differences being mainly described. In the second embodiment, the joint 10 of the first embodiment is an electrofusion joint 10-E. Fig. 8 shows an example of a piping system 200 according to this embodiment. The piping system 200 employs the configuration of the electrofusion joint 10-E shown in Fig. 8. Fig. 9 is a diagram showing the electrofusion joint 10-E according to this embodiment provided with a first terminal 52, a first indicator 55, a second terminal 57, and a second indicator 59, which will be described later.

[0046] 8, the piping system 200 includes an electrofusion joint 10-E, a pipe 20, and a cover 30. In this embodiment, the piping 20 is connected to one end of the electrofusion joint 10-E along the longitudinal direction of the piping system 200. Alternatively, the piping system 200 may be configured such that the pipe 20 is connected to both ends of the electrofusion joint 10-E along the longitudinal direction of the piping system 200.

[0047] The electric fusion joint 10-E comprises a hollow cylindrical joint body 12-E made of the same resin as that of the pipe 20, and a heating wire (described later) arranged spirally on the inner periphery of the joint body 12-E. The inner periphery of the joint body 12-E is provided with a fusion portion. The fusion portion is formed by inserting a heating wire into a spiral notch formed in the inner periphery of the joint body 12-E. Specifically, the electric fusion joint 10-E includes a joint body 12-E, a first heating portion 51, a first terminal 52, a first indicator 55, a second heating portion 56, a second terminal 57, and a second indicator 59.

[0048] A first heat generating portion 51 is provided on the inner circumferential surface of the joint body 12-E on the first connection port 11 side at one end in the length direction. The first heating portion 51 has a first heating wire 61 inserted into a first notched groove formed in a spiral shape on the inner circumferential surface side of the joint body 12-E. The opening portion of the first notched groove may have a spiral shape with the axis O1 of the joint body 12-E as the central axis and the distance from the central axis to the inner circumferential surface as the radius, for example. However, the first heating wire 61 may also be embedded in the joint body 12-E without the first notched groove.

[0049] The first terminal 52 is provided on the outer peripheral surface of the joint (electrofusion joint 10-E). More specifically, the first terminal 52 is provided on the outer peripheral surface of one of the first connection ports 11 of the electrofusion joint 10-E. The first terminal 52 is provided to pass current through the first heating wire 61 when electrically fusing the connected pipe 20 to the first heating part 51. For simplicity of illustration in Figure 8, the wire withdrawal hole and the first terminal 52 are shown in the same position, but in reality they are formed in positions spaced apart around the circumferential direction of the joint body 12-E. The first terminal 52 is connected to the connection wire 36 of the controller 35 for passing current. In this embodiment, the first heating wire 61 is connected to a second heating wire 62 described below, and a voltage is applied between the first terminal 52 and the second terminal 57. However, if the first heating wire 61 is not connected to the second heating wire 62, a voltage may be applied to the first heating wire 61 via the first terminal 52. In this case, the first terminals 52 may be provided at intervals in the circumferential direction on the peripheral surface of one end of the joint body 12-E on the first connection port 11 side.

[0050] The first indicator 55 is provided on the outer peripheral surface of the joint (electrofusion joint 10-E). More specifically, the first indicator 55 is provided on the outer peripheral surface of the joint body 12-E. The first indicator 55 is embedded in a recess (third recess) 54 provided on the outer peripheral surface of the joint body 12-E. The first indicator 55 protrudes radially outward from the third recess 54 during electrofusion when power is supplied to the first heating wire 61 via the first terminal 52. The protrusion of the first indicator 55 makes it possible to confirm that the first heating element 51 has been reliably electrofused to the pipe 20 to which it is connected. The first indicator 55 may be formed in a color different from that of the electrofusion joint 10-E so that it is easily visible even in dark installation spaces. In this case, the first indicator 55 may be colored by dyeing, printing, imprinting, or the like, and the color may be fluorescent or the like. The first indicator 55 may be integrally molded with the joint body 12-E using the same material, or may be integrally molded with a different material. Alternatively, the first indicator 55 may be formed from a material different from that of the joint body 12-E and attached to the joint body 12-E. The first indicator 55 is provided to confirm whether the first heating portion 51 has fused.

[0051] A second heat generating portion 56 is provided on the inner circumferential surface side of the first connection port 11 at the other end in the length direction of the joint body 12-E. The second heating portion 56 has a second heating wire 62 inserted into a second notched groove formed in a spiral shape on the inner circumferential surface side of the joint body 12-E. The opening portion of the second notched groove may have a spiral shape with the axis O1 of the joint body 12-E as the central axis and the distance from the central axis to the inner circumferential surface as the radius, for example. The second heat generating portion 56 is configured in substantially the same manner as the first heat generating portion 51. In this embodiment, the winding direction and number of turns of the spiral formed by the first heating wire 61 and the second heating wire 62 are not particularly limited.

[0052] The second terminal 57 is provided on the outer peripheral surface of the joint (electrofusion joint 10-E). More specifically, the second terminal 57 is provided on the outer peripheral surface of the other first connection port 11 of the electrofusion joint 10-E. The second terminal 57 is provided to pass current through the second heating wire 62 when electrically fusing the connected pipe 20 to the second heating part 56. For simplicity of illustration, the wire outlet hole and the second terminal 57 are shown in the same position in Fig. 8. The second terminal 57 is connected to the connection wire 36 of the controller 35 for passing current. In this embodiment, the first heating wire 61 is connected to the second heating wire 62, and a voltage is applied between the first terminal 52 and the second terminal 57. However, if the first heating wire 61 is not connected to the second heating wire 62, a voltage may be applied to the second heating wire 62 via the second terminal 57. In this case, the second terminals 57 may be provided at intervals in the circumferential direction on the peripheral surface of the first connection port 11 side of the other end of the joint body 12-E.

[0053] The second indicator 59 is provided on the outer peripheral surface of the joint (electrofusion joint 10-E). More specifically, the second indicator 59 is provided on the outer peripheral surface of the joint body 12-E. The second indicator 59 is embedded in a recess (fourth recess) 60 provided on the outer peripheral surface of the joint body 12-E. The second indicator 59 protrudes radially outward from the fourth recess 60 during electrofusion when power is supplied to the second heating wire 62 via the second terminal 57. The protrusion of the second indicator 59 makes it possible to confirm that the second heating element 56 has been reliably electrofused to the pipe 20 to which it is connected. The second indicator 59 may be formed in a color different from that of the electrofusion joint 10-E so that it is easily visible even in dark installation spaces. In this case, the second indicator 59 may be colored by dyeing, printing, imprinting, or the like, and the color may be fluorescent or the like. The second indicator 59 may be integrally molded with the joint body 12-E using the same material, or may be integrally molded with a different material. Alternatively, the second indicator 59 may be formed from a material different from that of the joint body 12-E and attached to the joint body 12-E. The second indicator 59 is provided to confirm whether the second heating portion 56 has fused. As described above, the second heat generating portion 56 is configured in substantially the same manner as the first heat generating portion 51.

[0054] The first heating wire 61 and the second heating wire 62 may be made of nichrome, iron-chromium alloy, copper-nickel alloy, copper-manganese alloy, iron-nickel alloy, manganese, copper-nickel-manganese alloy, nickel-chromium alloy, chromel, etc. The first heating wire 61 and the second heating wire 62 may be coated or uncoated. 8, the first heating wire 61 is connected to the second heating wire 62. Therefore, it is possible to apply electricity to the first heating wire 61 and the second heating wire 62 using both the first terminal 52 and the second terminal 57.

[0055] As shown in FIG. 8 , the second connection port 21 of the pipe 20 is inserted into the first connection port 11 of the electrofusion joint 10-E, and the connection wire 36 of the power controller 35 is connected to the first terminal 52 and the second terminal 57. Then, the controller 35 applies electricity to the heating wire, causing it to heat up. After applying electricity for a predetermined time with the required amount of power, the electricity is stopped and the electrofusion joint 10-E is cooled, allowing the pipe 20 to be extended and joined via the fused portion created by the electrofusion joint 10-E. The application of electricity to the heating wire fuses the inner surface of the electrofusion joint 10-E and the outer surface of the pipe 20 together, allowing the pipe 20 to be fused as if it were being extended. The fused portion is formed with a predetermined width around the entire circumference of the contact area between the outer surface of the pipe 20 and the inner surface of the electrofusion joint 10-E.

[0056] As with the first embodiment, the piping system 200 according to this embodiment is configured such that the cover 30 covers the outer peripheral surface of the electrofusion joint 10-E and the outer peripheral surface of the pipe 20 in the circumferential direction, and the first convex portion 31A and the second convex portion 31B of the cover 30 fit into the first recess 13 of the joint 10 and the second recess 23 of the pipe 20, respectively. This configuration eliminates the need for processes such as fastening with screws, and the joint 10 and the pipe 20 can be easily fixed by fitting the cover 30 onto the outer peripheral surfaces of the joint 10 and the pipe 20. Therefore, the piping system 200 according to this embodiment makes it possible to improve workability.

[0057] 9, the first recess 13 of the electrofusion joint 10-E is formed in the circumferential direction so as to avoid the first terminal 52. Similarly, the first recess 13 of the electrofusion joint 10-E is formed in the circumferential direction so as to avoid the second terminal 57. The first recess 13 of the electrofusion joint 10-E is desirably positioned in a location that will not affect the performance of the electrofusion joint 10-E when pressure is applied to the piping 20 and the inside of the electrofusion joint 10-E, that is, in a so-called cold zone position outside the electrofusion portion (first heat-generating portion 51). 4, the second recess 23 of the pipe 20 is formed in the circumferential direction so as to avoid a portion corresponding to the position of the first terminal 52 provided in the electrofusion joint 10-E. When the pipe 20 is also connected to the other end side of the electrofusion joint 10-E, the second recess 23 of the pipe 20 is formed in the circumferential direction so as to avoid a portion corresponding to the position of the second terminal 57 provided in the electrofusion joint 10-E. With this configuration, the cover 30 can be installed while avoiding the terminals (first terminal 52, second terminal 57), making installation of the cover 30 easy.

[0058] 9, the first recess 13 of the electrofusion joint 10-E is formed in the circumferential direction so as to avoid the first indicator 55. Similarly, the first recess 13 of the electrofusion joint 10-E is formed in the circumferential direction so as to avoid the second indicator 59. The first recess 13 of the electrofusion joint 10-E is desirably positioned in a location that will not affect the performance of the electrofusion joint 10-E when pressure is applied to the piping 20 and the inside of the electrofusion joint 10-E, that is, in a so-called cold zone position outside the electrofusion portion (second heat-generating portion 56). 4, the second recess 23 of the pipe 20 is formed in the circumferential direction so as to avoid a portion corresponding to the position of the first indicator 55 provided on the electrofusion joint 10-E. When the pipe 20 is also connected to the other end side of the electrofusion joint 10-E, the second recess 23 of the pipe 20 is formed in the circumferential direction so as to avoid a portion corresponding to the position of the second indicator 59 provided on the electrofusion joint 10-E. With this configuration, the cover 30 can be installed while avoiding the indicators (first indicator 55, second indicator 59), making it easy to install the cover 30.

[0059] An example of an outline of a method for constructing the piping system 100 (200) will be described. First, the second connection port 21 of the piping 20 is inserted into the first connection port 11 of the fitting 10 (electro fusion joint 10-E) (insertion step). The piping 20 is inserted into the fitting 10 (electro fusion joint 10-E) until the relative movement of the end of the first connection port 11 of the fitting 10 (electro fusion joint 10-E) is restricted by the stopper portion 22a of the piping 20. Next, in the insertion step, the cover 30 is fixed to the outer peripheral surface of the fitting 10 and the outer peripheral surface of the pipe 20. Specifically, the first convex portion 31A and the second convex portion 31B of the cover 30 are fitted into the first recess 13 of the fitting 10 and the second recess 23 of the pipe 20, respectively (fitting step). After the fitting step, the cover 30 is not removed. In this way, the installation of the piping system 100 is completed through the insertion process and the fitting process.

[0060] If the piping system employs an electrofusion joint 10-E, the surface of the piping 20 to be joined with the electrofusion joint 10-E is scraped with a scraper (scraping process) before the insertion process. The scraped piping 20 can maintain a good joint state for a certain period of time. After the scraping process, the outer surface of the second connection port 21 of the piping 20 and the inner surface of the first connection port 11 of the electrofusion joint 10-E are cleaned (cleaning process). After the fitting step, the connection wire 36 of the power controller 35 is connected to the first terminal 52 and the second terminal 57, and the controller 35 passes current through the heating wire to heat it. By passing current through the heating wire, the inner peripheral surface of the electric fusion joint 10-E and the outer peripheral surface of the pipe 20 are fused to each other (fusion step). The temperature of the heating wire during current passing need only be such that the fused portion melts, and heating is performed at, for example, 230°C. After the fusion step, the electrofusion joint 10-E and the pipe 20 are cooled (cooling step). After the cooling step, the cover 30 is not removed. In this way, the construction of the piping system 200 is completed through the scraping process, cleaning process, insertion process, fitting process, fusion process, and cooling process.

[0061] The technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, in the first and second embodiments, the first connection port 11 of the fitting 10 (electric fusion fitting 10-E) is a socket and the second connection port 21 of the piping 20 is a spigot, but the first connection port 11 of the fitting 10 (electric fusion fitting 10-E) may be a spigot and the second connection port 21 of the piping 20 may be a spigot. [Explanation of symbols]

[0062] 10 Joints 10-E Electric fusion joint 11 First connection port 12, 12-E Fitting body 13 First recess 20 Piping 21 Second connection port 22 Piping body 23 Second recess 30 Cover 31 Convex part 31A First convex part 31B Second convex part 37 Protrusion 37A 1st protrusion 37B 2nd protrusion 52 Terminal 1 55 First Indicator 57 Terminal 2 59 Second Indicator 100,200 Piping System

Claims

1. a fitting having a connection port; A pipe connected to the connection port; a cover that covers an outer peripheral surface of the joint and an outer peripheral surface of the pipe along a circumferential direction; Equipped with a first circumferential recess is provided on the outer peripheral surface of the joint; a second circumferential recess is provided on the outer peripheral surface of the pipe; The cover includes a first protrusion that fits into the first recess and a second protrusion that fits into the second recess. Piping system.

2. the first protrusion and the second protrusion of the cover include protrusions that protrude in the longitudinal direction of the piping system. The piping system of claim 1 .

3. The piping system according to claim 1 or 2, wherein a length between the first convex portion and the second convex portion of the cover is equal to or less than a distance between the first recess and the second recess.

4. The piping system of claim 1 , wherein the joint is an electrofusion joint.

5. A terminal is provided on the outer peripheral surface of the electric fusion joint, The first recess is formed in the circumferential direction so as to avoid the terminal. The piping system of claim 4.

6. an indicator is provided on the outer peripheral surface of the electric fusion joint; The first recess is formed to avoid the indicator in the circumferential direction.

6. The piping system according to claim 4 or 5.

Images