Rehabilitation piping

Abstract

To provide rehabilitation piping capable of rehabilitating existing piping that is difficult to replace by excavation due to its on-site installation condition.SOLUTION: Rehabilitation piping of the present invention is rehabilitation piping for rehabilitating existing piping installed underground or under a structure, the rehabilitation piping housed inside the existing piping and comprising a plurality of resin pipes made of polyolefin resin and an electric fusion joint extending and joining the plurality of resin pipes. It is preferable that the rehabilitation piping of the present invention has a diameter reduction rate expressed by the relation (outer diameter of the resin pipe / inner diameter of the existing piping) of 35% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] When updating existing pipes such as water pipes or gas pipes buried underground, it may not be possible to replace the existing pipes because excavation work cannot be carried out in the surrounding area due to the surrounding road conditions or the circumstances of the installation location. In such cases, a technology is known in which a deformable polyethylene resin pipe or the like is inserted inside the existing pipe while leaving it in place to rehabilitate it. The following Patent Document 1 discloses a method for lining the inside of an existing pipe by inserting a polyethylene resin pipe into the inside of the existing pipe, applying pressure to the inside of the resin pipe while heating it to the softening temperature of polyethylene or higher after insertion, and expanding the diameter of the polyethylene resin pipe. According to the technology described in Patent Document 1, it is described that a polyethylene resin film having a thickness that fits along the inner wall of the existing pipe can be formed, thereby forming an inside pipe lining. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-170367 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, when it is not possible to replace the existing piping, the existing piping is left in place and a thin plastic pipe with a small diameter is inserted into the existing piping to create an internal lining, which is then carried out on-site. For example, a polyethylene pipe material, the cross-sectional shape of which has been reduced in diameter in advance to a circular or heart shape, is inserted while being heated to a temperature above its softening point and below its melting point, and then pressure is applied from the inside to expand the diameter and form it into a tubular shape that fits along the existing piping, creating a rehabilitated pipeline. However, this type of construction requires special equipment, such as the installation of a large steam generator, the installation of a drum wrapped in polyethylene pipe material, a rotating machine specifically for the drum, etc. In addition, space is required to install these large pieces of equipment, and a vertical hole must be formed in the ground to reach the existing piping, so the vertical hole must also be excavated large to accommodate the special equipment, making the construction itself large-scale, limiting the number of sites where it can be carried out, and requiring specialized construction companies, which increases the construction cost.

[0005] In view of the above-mentioned circumstances, the present invention aims to provide a rehabilitation pipe that can be applied when rehabilitating a pipeline by inserting a plastic pipe inside the existing pipe while leaving it in place, and that can be installed as simply as possible without requiring large-scale on-site construction. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention proposes the following aspects. <1> A rehabilitation pipe according to one embodiment of the present invention is a rehabilitation pipe for rehabilitating an existing pipe, and is characterized in that it is housed inside the existing pipe, and is equipped with an electric fusion joint having a plurality of resin pipes made of polyolefin-based resin and a resin pipe body that joins the plurality of resin pipes, and has a diameter reduction rate expressed by the relationship (outer diameter of the resin pipes / inner diameter of the existing pipe) of 35% or less.

[0007] A new rehabilitated pipeline can be formed inside an existing pipe by providing a rehabilitated pipeline consisting of multiple plastic pipes joined together via electric fusion joints inside the existing pipe. Electric fusion joints can adjust the amount of heat generated uniformly by inputting a specific amount of electricity without requiring large-scale equipment. Therefore, plastic pipes can be reliably fused without requiring special equipment, and a rehabilitated pipeline can be obtained that is easy to install and has no defects in the fused parts. In addition, plastic pipes made of polyolefin resin are desirable as materials for constructing rehabilitated pipelines from the viewpoints of earthquake resistance, durability, and not having a negative effect on water quality. The diameter reduction rate is kept to a minimum at 35% or less, providing a piping structure that ensures the necessary flow rate as much as possible even after rehabilitation. In addition, the outer diameter of the electric fusion joint is also equal to or smaller than the inner diameter of the existing pipe, so if a vertical hole is formed to connect to an existing pipe installed underground or under a structure, after joining the plastic pipe inside the vertical hole, it can be pulled into the existing pipe together with the plastic pipe to form a rehabilitated pipeline.

[0008] <2> The above <1> In the rehabilitation piping related to the above, it is preferable that the electric fusion joint comprises a cylindrical plastic pipe body having fitting receptacle portions at both longitudinal ends into which the end of the plastic pipe can be inserted, a first heating portion having an electric heating wire arranged on the inner surface side of one of the fitting receptacle portions, and a second heating portion having an electric heating wire arranged on the inner surface side of the other fitting receptacle portion.

[0009] By inserting a plastic pipe into one fitting socket and the other fitting socket and passing electricity through the first and second heating parts, the two plastic pipes can be fused and extended with an electric fusion joint. By inserting multiple plastic pipes into the inside of an existing pipe and fusing them in sequence with an electric fusion joint, a rehabilitated pipeline can be constructed in which multiple plastic pipes are extended and connected inside the existing pipe.

[0010] <3> The above <1> In the rehabilitation piping related to the above, it is preferable that the electric fusion joint comprises a cylindrical plastic pipe body having a fitting spigot portion at both longitudinal ends which can be inserted into the inside of the plastic pipe, a stopper formed on the outer surface of the plastic pipe body so as to protrude outward and which can regulate the insertion position of the pipe end of the plastic pipe when the fitting spigot portion is inserted into the inside of the plastic pipe, a first heating section having an electric heating wire arranged in one of the fitting spigot portions, and a second heating section having an electric heating wire arranged in the other fitting spigot portion.

[0011] When plastic pipes are joined together using an electric fusion joint having a plastic pipe body with a joint socket that can be inserted inside the plastic pipes to be joined to form a rehabilitated pipeline, the plastic pipes to be used to form the rehabilitated pipeline can be installed in the existing piping with an outer diameter as large as possible. Therefore, when rehabilitating an existing pipe, a piping structure that can easily ensure the necessary flow rate even after rehabilitation can be provided.

[0012] <4> The above <1> In the rehabilitation piping related to the above, it is preferable that the pipe comprises an electric fusion joint having a plastic pipe main body that receives the tip side of the reducer pipe, a plastic pipe connected to the rear end side of the reducer pipe, and a plastic pipe connected to the other end side of the electric fusion joint, and that the pipe comprises a heating section having an electric heating wire provided on the inner side of the plastic pipe main body.

[0013] When the end of a plastic tube is reduced in diameter via a reducer tube and connected to an electric fusion joint, the pressure loss of the fluid flowing inside can be minimized, making it easier to ensure a sufficient flow rate.

[0014] <5> The above <2> or <4> In the rehabilitation pipe according to the above, it is preferable that a terminal connected to the heating wire is provided on an outer periphery of the plastic pipe body. <6> The above <3> In the rehabilitation pipe according to the present invention, it is preferable that the stopper is provided on an outer periphery thereof with a terminal connected to the heating wire.

[0015] Electric power for electric fusion bonding can be supplied to the heating wire via the terminal. By accurately supplying the electric power using a controller, the amount of heat generated can be adjusted to the specified level, and the resin pipe can be bonded via the fusion part without any fusion defects.

[0016] <7> The above <2> or <4> In the rehabilitation pipe according to the present invention, it is preferable that an indicator for confirming fusion is provided on the outer periphery of the plastic pipe body.

[0017] By providing an indicator portion for confirming fusion, it is possible to accurately grasp the completion of fusion with the plastic pipe, and the plastic pipe can be joined via a fusion portion that is not defectively fused. Effect of the Invention

[0018] The rehabilitation pipe of the present invention can form a new pipeline inside an existing pipe by providing a rehabilitation pipeline made of multiple resin pipes made of polyolefin resin joined together via electric fusion joints inside the existing pipe. When multiple resin pipes are fused together using electric fusion joints, the amount of electricity can be easily controlled precisely, and the resin pipes can be joined by reliable fusion. This makes it possible to form a rehabilitation pipeline without defects in the fused parts. In addition, the diameter reduction rate is kept to a minimum at 35%, providing a piping structure that ensures the necessary flow rate as much as possible even after rehabilitation. Furthermore, the outer diameter of the electric fusion joint is also equal to or smaller than the inner diameter of the existing piping, so when a vertical hole is formed to connect to an existing piping installed underground or under a structure, after joining the plastic pipe in the vertical hole, it can be pulled into the existing piping together with the plastic pipe to form a rehabilitated pipeline. [Brief description of the drawings]

[0019] [Figure 1] 1 is a partial cross-sectional view showing a piping structure including a rehabilitation pipe according to a first embodiment of the present invention. [Diagram 2] 2 is a partial cross-sectional view showing the state in which an inlet side vertical hole and an outlet side vertical hole have been formed to create the piping structure shown in FIG. 1. [Diagram 3] FIG. 2 is a partial cross-sectional view showing a state in which multiple plastic pipes are inserted into an existing piping from an inlet side vertical hole to create the piping structure shown in FIG. 1. [Figure 4] 1 is a cross-sectional view showing an example of an electric fusion joint applied to the piping structure of the first embodiment. [Diagram 5] 4 is a side view showing a state in which a plastic pipe to be joined is attached to an electric fusion joint. FIG. [Figure 6] FIG. 4 is a side view showing a state in which electricity is being applied to the electric fusion joint from a controller. [Figure 7] FIG. 4 is a side view showing the state in which plastic pipes are fused to each other using an electric fusion joint. [Figure 8] A cross-sectional view showing the state in which a plastic pipe that has been extended inside an existing piping is moved to the outlet shaft side in order to realize the piping structure shown in Figure 1. [Figure 9] 2 is a cross-sectional view showing the process of moving an additional plastic pipe inside an existing piping to realize the piping structure shown in FIG. 1. [Figure 10] FIG. 2 is a partial cross-sectional view showing the state in which a plastic pipe extended inside an existing piping is fused to a plastic pipe located below the outlet-side vertical hole in order to realize the piping structure shown in FIG. 1. [Figure 11] FIG. 6 is an exploded perspective view of a main part of a rehabilitation pipe according to a second embodiment of the present invention, as viewed from one direction. [Figure 12] FIG. 11 is an exploded perspective view of the main part of the rehabilitation pipe according to the second embodiment, as viewed from another direction. [Figure 13] FIG. 11 is a cross-sectional view showing a main part of a rehabilitation pipe according to a second embodiment. [Figure 14] FIG. 11 is a plan view of an electric fusion joint applied to a rehabilitation pipe according to the second embodiment. [Figure 15] FIG. 11 is an exploded plan view showing a main part of a rehabilitation pipe according to a third embodiment of the present invention. [Figure 16] FIG. 11 is an exploded perspective view of the main part of the rehabilitation pipe according to the third embodiment, as viewed from another direction. [Figure 17] FIG. 11 is a plan view showing a rehabilitation pipe according to the third embodiment. [Figure 18] FIG. 11 is a side view showing a main part of a rehabilitation pipe according to a fourth embodiment of the present invention. [Figure 19] FIG. 13 is a cross-sectional view showing a main part of a rehabilitation pipe according to a fifth embodiment of the present invention. [Figure 20] FIG. 13 is a cross-sectional view showing a connected state of a rehabilitation pipe according to the fifth embodiment. [Figure 21] FIG. 13 is a cross-sectional view showing a main part of a rehabilitation pipe according to a sixth embodiment of the present invention. [Figure 22] FIG. 13 is a cross-sectional view showing a connection state of a rehabilitation pipe according to the sixth embodiment. [Diagram 23] FIG. 13 is a cross-sectional view showing a connection state of a rehabilitation pipe according to a seventh embodiment of the present invention. [Figure 24] FIG. 13 is a cross-sectional view showing a connection state of a rehabilitation pipe according to an eighth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a piping structure using a rehabilitation pipe according to a first embodiment of the present invention and a pipe rehabilitation method for an existing pipe will be described with reference to Figs. First Embodiment FIG. 1 shows a cross section of an existing pipe 1 buried underground, and also shows a state in which a new rehabilitating pipeline (newly installed pipe section) 2 has been formed inside the existing pipe 1 along its length. In the area where the rehabilitated pipeline 2 is formed in Fig. 1, an inlet side pit 3 and an outlet side pit 4 are formed by excavating the ground at a predetermined interval. Also, in an area other than the area between the inlet side pit 3 and the outlet side pit 4, an additional inlet side pit 5 is formed to the side of the inlet side pit 3 shown in Fig. 1.

[0021] Note that Fig. 1 is a cross-sectional view at the time when a rehabilitating pipeline 2 has been formed inside an existing pipe 1, and the rehabilitation work can be completed by backfilling the inlet side vertical hole 3, the outlet side vertical hole 4, and the additional inlet side vertical hole 5 from the state shown in Fig. 1. Also, after forming the rehabilitating pipeline 2 inside the existing pipe 1, a filler such as mortar may be filled into the gaps in the existing pipe 1, or the rehabilitation work may be completed by backfilling the inlet side vertical hole 3, the outlet side vertical hole 4, and the additional inlet side vertical hole 5 from the state shown in Fig. 1 without filling the gaps. The rehabilitating pipeline 2 is constructed by joining together a number of straight plastic pipes 6. In the joined plastic pipes 6, 6 shown in the first embodiment, their ends 6a are joined together via an electric fusion joint 30. The electric fusion joint 30 and the fusion portion will be described in detail later, but first, the plastic pipe 6 will be described.

[0022] The resin pipe 6 is preferably made of a thermoplastic resin such as a polyolefin resin. The resin pipe 6 made of a polyolefin resin has a higher tensile breaking elongation measured according to JIS K 6815-1 and JIS K 6815-3 than a rigid polyvinyl chloride pipe. The tensile breaking elongation of a rigid polyvinyl chloride pipe is 50 to 150%, whereas the tensile breaking elongation of a polyolefin resin pipe is 350% or more. In particular, a high density polyethylene pipe of PE100 has a tensile breaking elongation of 500% or more by the extrapolation method specified in ISO / TR9080, and therefore can be more effectively prevented from being damaged by an earthquake.

[0023] 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 preferable to adopt polyethylene from the viewpoint of strength, etc. When selecting polyethylene, it is preferable to appropriately select one of low density polyethylene, medium density polyethylene, high density polyethylene, etc. according to the required durability desired for the resin pipe 6. A resin pipe 6 made of polyethylene resin can be used from the viewpoint of not affecting earthquake resistance, durability, water quality, etc. In particular, when the resin pipe 6 is used as a drinking water pipe, a resin pipe made of high density polyethylene is preferable.

[0024] The specific gravity of the thermoplastic resin is not particularly limited, but is, for example, 942 to 953 kg / m 3 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 a pigment, an ultraviolet absorber, an antioxidant, and a lubricant. The melting point of the thermoplastic resin (ie, the melting temperature of the resin pipe 6) is not particularly limited, but is preferably 125 to 260°C, and more preferably 125 to 150°C.

[0025] The resin pipe 6 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 ethylene-vinyl alcohol copolymer resin, the resin pipe 6 may be a pipe for any purpose, such as a drinking water pipe, a gas pipe, or a sewer pipe. This is because the surface layer containing 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.

[0026] The surface layer may include 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 includes these fibers, the tensile strength of the resin pipe 6 can be increased and thermal expansion can be further suppressed. The surface layer may also include a fluororesin. When the surface layer includes fluorine, resistance (chemical resistance) to acids, alkalis, and the like can be increased. A layer similar to the above surface layer may also be provided inside the wall of the resin pipe 6.

[0027] The SDR value, which is the ratio of the outer diameter D to the wall thickness T of the resin pipe 6, is preferably 13.5 or less. If the SDR value exceeds 13.5, the pipe thickness becomes too thin and there is a risk that the pipe cannot withstand the internal pressure of the fluid when the fluid flows inside. If the SDR value is too low, the pipe thickness becomes too thick and there is a risk that a sufficient flow rate cannot be ensured. For this reason, the lower limit of the SDR value is preferably 6 or more, and more preferably 7.4 or more.

[0028] Generally, in pipe thickness design, for a pipe through which water flows, the relationship between the tensile circumferential stress generated in the pipe due to the internal water pressure (the tensile stress generated in the circumferential direction in the cross section of the pipe) follows the Naday equation shown in equation (1) below. 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).

[0029] Based on the above-mentioned Naday formula, 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 formula (2). σ 50 / S1=P d (Dt) / 2t …(2) formula However, in equation (2), σ 50 : 50-year creep strength of polyethylene water distribution pipe (10MPa), S1: σ 50 Safety factor for (here assumed to be 2), P d : Maximum allowable pressure (static pressure 0.75 x water hammer pressure 0.25 = 1.0 PMa) By modifying the above formula (2), the SDR (Standard Dimension Ratio) value can be calculated using the following formula (3). SDR = D / t = 1 + (2σ 50 ) / P d ·S1=1+(2×10) / (1×2)=11…(3) formula

[0030] According to the pipe thickness design for water pipes, which was calculated with a safety factor of 2 as mentioned above, it is found that an SDR value of 11 is favorable, but if the pipe is to be rehabilitated 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. Note that if the standard SDR value for polyethylene water pipes is 11, the SDR value when the flow rate drops by 40% (commonly calculated with a flow velocity coefficient of 140 and a hydraulic gradient of 3%) is less than SDR6, so an SDR value of 6 or more is preferable.

[0031] The plastic pipe 6 is a pipe to be housed inside the existing piping 1, but is a self-supporting pipe, unlike the thin, non-self-supporting pipes used in the prior art with inner pipe linings. Moreover, it is preferable that the plastic pipe 6 be a plastic pipe with little deformation, with an ovality of 4.5 mm or less. It is preferable that the method of measuring the ovality of the resin pipe 6 conform to the Japan Water Works Association standard: JWWAK144 (polyethylene pipe for water distribution). Measure each dimension with a measuring device such as a vernier caliper at 23±2°C 24 hours or more after the manufacture of the resin pipe, and condition the pipe for 4 hours or more before measuring. In addition, if the temperature measurement is outside of 23±2°C, such as when measuring dimensions outdoors, it is preferable to convert the measured values ​​to dimensions at 23°C based on the following formula (4).

[0032] L 23 ={1+α×(23-t)}×L t …(4) formula In equation (4), L 23 : Dimensions at 23°C (converted value), α: Linear expansion coefficient (1 / °C) (polyethylene pipe for water supply: 12.0×10 -5 ), t: Temperature at time of measurement (℃), L t : Dimensions (measured value) at t℃ For example, in formula (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 resin pipe temperature 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. D 23 ={1+12.0×10 -5 ×(23-35)}×125.9=125.7mm

[0033] The resin pipe 6 applied to this embodiment preferably has a flexure rate of 5% or less. The flexure rate is preferably measured in accordance with the Japan Water Works Association standard: JWWA K144 (polyethylene pipe for water distribution).

[0034] In the structure shown in Fig. 1, since the rehabilitating pipeline 2 is constructed inside the existing pipe 1, the outer pipe diameter of the plastic pipe 6 (rehabilitating pipeline 2) needs to be smaller than the inner pipe diameter of the existing pipe 1. It is desirable that the outer pipe diameter (mm) of the rehabilitating pipeline 2 and the inner pipe diameter (mm) of the existing pipe 1 have the relationship shown in Table 1 below. Furthermore, when applying this embodiment, the outer pipe diameter is not particularly limited, but it is preferable to apply it to a rehabilitating pipe with an outer diameter of 315 mm or less. With the outer pipe diameter in this range, fusion is possible with a small amount of heat and the electric fusion joint can be made compact, making it easy to install. The inner diameter of the rehabilitated pipeline 2 (plastic pipe 6) is inevitably smaller than the inner diameter of the existing pipe 1. However, considering the current situation at the site where the existing pipe 1 is rehabilitated, the existing pipe 1 is a pipe that has been in place for 30 to 50 years, and in Japan, the current population is overwhelmingly smaller than the current population 30 to 50 years ago. Considering this, it is generally considered that there are no problems in applying the rehabilitated pipeline 2 even if the flow rate is somewhat reduced due to the smaller inner diameter of the rehabilitated pipeline 2. Here, it is preferable that the diameter reduction rate expressed by the relationship (outer diameter of the plastic pipe / inner diameter of the existing pipe) is 35% or less. By maintaining this relationship, the rehabilitated pipeline 2 can ensure the largest possible flow rate.

[0035] [Table 1]

[0036] The nominal diameter (nominal diameter of the resin pipe 6), outer diameter: D, and thickness: t of the rehabilitated pipeline 2 can be selected from the sizes shown in Table 2 below. In Table 2, PTC K 03 indicates the Association standard for polyethylene pipe systems for water distribution (Politec Association standard), and PWA 001 indicates the Association standard for polyethylene pipe systems for building facilities.

[0037] [Table 2]

[0038] The resin pipe 6 preferably has a tensile yield strength of 20 MPa or more, and a tensile elongation at break of 350% or more. The resin pipe 6 preferably has a tensile modulus of 800 to 1100 MPa. The flexural modulus of 1000 to 1200 MPa, and a water pressure breaking strength of 4.0 MPa or more. These specific values ​​can be measured in accordance with the above-mentioned Japan Water Works Association standard: JWWA K144 (polyethylene pipe for water distribution). As will be described later in the rehabilitation method for an existing pipe, since the plastic pipe 6 is pulled and moved a predetermined distance along the length of the existing pipe 1 inside the existing pipe 1 during construction, it is preferable to provide a protective layer on the outer circumferential surface of the plastic pipe 6 to prevent scratches or the like from being caused on the outer circumferential surface of the plastic pipe 6. The protective layer may be provided separately on the outer circumferential surface of the plastic pipe 6, may be integrated therewith, or may be provided separately by a method such as wrapping.

[0039] In the extended resin pipe 6, the fused portion where the end portions 6a are fused to each other is formed, for example, by an electric fusion joint 30 in accordance with the procedure shown in Figs. As a preparation process for the fusion joint made by the electric fusion joint 30, it is preferable to adjust the end surface shape of the end 6a of one plastic pipe 6 to be joined and the end 6a of the other plastic pipe 6 as shown in Figure 5 by a method such as cutting as necessary, and then clean it.

[0040] As an example, the electric fusion joint 30 has a single-tube resin pipe main body 50 made of the same resin as that constituting the resin pipe 6, as shown in Fig. 5, and an electric heating wire, not shown in Fig. 7, which is arranged in a spiral shape on the inner peripheral surface side of the resin pipe main body 50. The resin pipe main body 50 has a length and an inner diameter that allow the end of the resin pipe 6 to be joined to be inserted by the required length. The ends of the heating wire arranged in a spiral shape on the inner peripheral surface of the resin pipe body 50 are connected to terminals 52 and 57 protruding on the outer peripheral side of the resin pipe body 50 .

[0041] As shown in FIG. 5, the end portions 6a of the resin pipes 6, 6 are inserted into one and the other of the resin pipe main body 50 in the length direction, and the connection wires 34 of the controller 33 for current supply are connected to the terminals 52, 57 as shown in FIG. 6. After this, the controller 33 supplies electricity to the heating wire to heat it. After a predetermined time with the necessary amount of electricity is supplied, the electricity supply is stopped and the wire is cooled, and the resin pipes 6, 6 can be joined by adding them through the fusion portion formed by the electric fusion joint 30. By supplying electricity to the heating wire, the inner peripheral surface of the resin pipe main body 50 and the outer peripheral surface of the resin pipe 6 are mutually fused, so that the resin pipes 6, 6 can be fused as if they were being added. Since the inside of the resin pipe main body 50 cannot be shown in FIG. 7, the position of the fusion portion 35 formed between the resin pipe main body 50 and the resin pipe 6 is shown by a chain line. The fusion portion 35 is formed with a predetermined width all around the contact portion between the outer peripheral surface of the resin pipe 6 and the inner peripheral surface of the resin pipe main body 50.

[0042] In the above explanation based on Figs. 5 to 7, the detailed structure of electric fusion joint 30 has been omitted, but as an example, electric fusion joint 30 may employ the detailed structure shown in Fig. 4. The electric fusion joint 30 shown in Fig. 4 has a fusion part on the inner circumferential surface of a resin pipe body 50 made of thermoplastic resin into which a connecting resin pipe is inserted. The fusion part is formed by inserting an electric heating wire into a spiral notched groove formed on the inner circumferential surface of the resin pipe body. More specifically, the electric fusion joint 30 includes a plastic tube body 50, a first heating portion 51, first terminals 52, 53, a first indicator 55, a second heating portion 56, second terminals 57, 58, and a second indicator 59.

[0043] The resin pipe body 50 made of a thermoplastic resin is formed into a hollow cylindrical shape. As the thermoplastic resin constituting the resin pipe body 50, it is preferable to use a polyolefin resin similar to that of the resin pipe 6 described above.

[0044] Examples of methods for molding the resin pipe body 50 include extrusion molding and injection molding. In particular, extrusion molding makes it easy to mold the resin pipe body 50 into a long one with a large diameter. The resin pipe body 50 is formed to have the same inner diameter and the same outer diameter from one end to the other end in the length direction. An end 6a of one of the resin pipes 6 to be connected is inserted into one end of the resin pipe body 50, and an end 6a of the other of the resin pipes 6 to be connected is inserted into the other end of the resin pipe body 50. In the resin pipe body 50, the side into which one of the resin pipes 6 is inserted is one of the joint sockets 50A, and the side into which the other of the resin pipes 6 is inserted is the other joint socket 50B. In this way, the resin pipe body 50 has joint sockets at both ends in the length direction.

[0045] (First heating part) A first heating portion 51 is provided on the inner circumferential surface of the resin pipe main body 50 at one end 50a in the longitudinal direction (the inner circumferential surface on the one joint receiving portion 50A side). 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 peripheral surface side of the plastic pipe body 50. The opening portion of the first notched groove may have a spiral shape with the pipe axis O of the plastic pipe body 50 as the central axis and the distance from the central axis to the inner peripheral surface as the radius, for example.

[0046] The first terminals 52, 53 are provided on the peripheral surface of one end of the resin pipe main body 50 at a distance from each other in the circumferential direction. The first terminals 52, 53 are provided to pass electricity through the first heating wire 61 when electrically fusing the connected plastic pipe 6 to the first heating part 51. For the sake of simplicity in FIG. 4, the wire withdrawal hole and the first terminals 52, 53 are shown in the same positions, but in reality they are formed at positions spaced apart in the circumferential direction of the plastic pipe main body 50.

[0047] The first indicator 55 is embedded in a first recess 54 provided on the outer circumferential surface of the plastic pipe main body 50. The first indicator 55 protrudes radially outward from the first recess 54 during electrical fusion in which power is supplied to the first heating wire 61 via the first terminals 52, 53. The protrusion of the first indicator 55 makes it possible to confirm that the first heating portion 51 has been securely electrically fused to the plastic pipe 6 to be connected. The first indicator 55 may be molded integrally with the resin pipe body 50 using the same material, or may be formed using a material different from that of the resin pipe body 50 and attached to the resin pipe body 50. The first indicator 55 is provided to confirm the fusion of the first heating portion.

[0048] (Second heating part) A second heating portion 56 is provided on the inner circumferential surface of the resin pipe main body 50 on the other end 50b side in the longitudinal direction (the inner circumferential surface on the other joint socket portion 50B side). 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 peripheral surface side of the plastic pipe body 50. The opening portion of the second notched groove may have a spiral shape with the pipe axis O of the plastic pipe body 50 as the central axis and the distance from the central axis to the inner peripheral 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 the number of turns of the spiral formed by the first heating wire 61 and the second heating wire 62 are not particularly limited.

[0049] The second terminals 57, 58 are provided on the peripheral surface of the other end of the resin pipe body 50 at a distance from each other in the circumferential direction. The second terminals 57, 58 are provided to pass electricity through the second heating wire 62 when electrically fusing the connected resin pipe 6 to the second heating part 56. For simplicity of illustration in Fig. 4, the wire withdrawal hole and the second terminals 57, 58 are shown in the same positions. The second indicator 59 is embedded in a second recess 60 provided on the outer circumferential surface of the plastic pipe main body 50. The second indicator 59 protrudes radially outward from the second recess 60 during electrical fusion when power is supplied to the second heating wire 62 via the second terminals 57, 58. The protrusion of the second indicator 59 makes it possible to confirm that the second heating part 56 has been securely electrically fused to the connected plastic pipe 6. The second indicator 59 is provided to confirm fusion of the second heating part. As described above, the second heat generating portion 56 is configured in substantially the same manner as the first heat generating portion 51.

[0050] 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. 4, the first heating wire 61 is arranged in a spiral shape so as to have a folded-back portion at a position toward the center in the longitudinal direction of the resin pipe body 50. Therefore, electricity can be passed through the first heating wire 61 by using the first terminals 52 and 53. The second heating wire 62 is arranged in a similar manner, and electricity can be passed through the second heating wire 62 by using the second terminals 57 and 58.

[0051] The electric fusion joint 30 shown in FIG. 4 can be applied to the welding process previously described with reference to FIGS. 5 to 7, and can be suitably used when extending and fusing and joining resin pipes 6, 6. With this electric fusion joint 30, it is easy to confirm that fusion joining has been performed reliably by checking the protrusions of the indicators 55, 59, so that the plastic pipes 6, 6 can be reliably fusion joined without fusion defects. Therefore, when the existing piping 1 is rehabilitated using the resin pipe 6, the pipe can be rehabilitated reliably without generating any poorly joined portions.

[0052] A method for rehabilitating an existing pipe 1 by forming a rehabilitation pipeline 2 shown in FIG. 1 will be described below. Although the explanation will vary slightly depending on whether the existing pipe 1 is a water pipe, a gas pipe, or a sewer pipe, the following will take as an example a case where the existing pipe 1 is buried underground. Fig. 2 shows a state in which only a portion of an existing pipe 1 has already been rehabilitated with a plastic pipe 6. Fig. 2 is drawn to explain the process of forming a rehabilitated pipeline 2 along the entire existing pipe 1 by sequentially joining other plastic pipes 6 to the partially rehabilitated plastic pipe 6.

[0053] As shown in FIG. 2, an inlet side pit 3 and an outlet side pit 4 are formed at a predetermined interval along an existing pipe 1 buried at a predetermined depth in a ground 11 below ground 10. Regarding the installation environment of the existing pipe 1, it is difficult to excavate a wide area along the existing pipe 1. However, if the environment allows the formation of an inlet side vertical hole 3 and an outlet side vertical hole 4 that reach the ground at intervals along the existing pipe 1 into the ground 11 as shown in Figure 2, the pipeline rehabilitation method described below can be applied. In addition, when the existing piping 1 is a sewer pipe, among a plurality of manholes formed at predetermined intervals along the sewer pipe, adjacent manholes may be used as the inlet shaft 3 or the outlet shaft 4.

[0054] As shown in Fig. 2, the outlet side shaft 4 is formed to include the plastic pipe 6 located at the end of the area already rehabilitated with the plastic pipe 6. As an example, when the end 6a of the rehabilitated plastic pipe 6 is viewed in plan, the end 6a is formed to reach the existing piping 1 from the ground 10 so that it is located a sufficient length inside the outlet side shaft 4. In addition, an outlet side access port 1a is formed in the existing piping 1 below the outlet side shaft 4 so as to communicate with the outlet side shaft 4 and the inside of the existing piping 1. By forming the outlet side access port 1a in the peripheral wall of the existing piping 1, the outlet side shaft 4 and the inside of the existing piping 1 are communicated with each other. Also, an inlet side shaft 3 is formed at a position along the existing piping 1 at a predetermined distance from the outlet side shaft 4. The inlet side shaft 3 is formed so as to reach the existing piping 1 below it from the ground 10. It is preferable that the inner diameter of the inlet side shaft 3 is approximately the same as that of the outlet side shaft 4 or slightly larger. Once the inlet side shaft 3 is formed, an inlet side working port 1b is formed in the existing piping 1 below it so as to communicate between the inlet side shaft 3 and the inside of the existing piping 1. By forming the inlet side working port 1b in the peripheral wall of the existing piping 1, the inlet side shaft 3 and the inside of the existing piping 1 are communicated. The inner diameter of the inlet side vertical hole 3 can be slightly larger than the length of one of the resin pipes 6. If there is sufficient free space at the position where the inlet side vertical hole 3 is to be formed in the installation environment of the existing piping 1, the inner diameter of the inlet side vertical hole 3 may be formed larger.

[0055] After the inlet side vertical hole 3 is formed, for example, two plastic pipes 6 are inserted into the existing piping 1 through the inlet side vertical hole 3. The length of the plastic pipes 6 used here is set to a length that allows them to be inserted into the existing piping 1 through the inlet side vertical hole 3 and the inlet side working port 1b. When inserting two plastic pipes 6 into the existing piping 1, it is preferable to adjust the position of the plastic pipes 6 along the internal space of the existing piping 1 as shown in FIG. 3, and accommodate the ends 6a of the two plastic pipes 6 so that they are located at the center of the inlet-side vertical hole 3. After the ends 6a of the two plastic pipes 6 are aligned, the ends 6a of the two plastic pipes 6 are positioned facing each other using a support 13 such as a stand required for fusion as shown in FIG. 3. After this, the two plastic pipes 6 are fused by the electric fusion joint 30 according to the fusion procedure previously described with reference to FIGS. 5 to 7. By fusion, the two plastic pipes 6 are joined in a state of being extended via the electric fusion joint 30 as shown in FIG. 7.

[0056] Once the fusion of the two plastic pipes 6 is complete, the two plastic pipes 6 are slid from the inlet side vertical hole 3 to the outlet side vertical hole 4. The leading plastic pipe 6 is moved to a position close to the outlet side vertical hole 4, and the two plastic pipes 6 are slid along the existing piping 1 so that the end (rear end) 6c ​​of the rear plastic pipe 6 is positioned at the center of the inlet side vertical hole 3.

[0057] Thereafter, a new plastic pipe 6 is introduced into the existing piping 1 again through the inlet-side vertical hole 3. Then, the newly introduced plastic pipe 6 is fused to the rear end of the rear end side plastic pipe 6 that has been previously fused, according to the fusion procedure using the electric fusion joint 30 previously described with reference to Figures 5 to 7. As a result, a plurality of plastic pipes 6 are introduced and joined into the existing piping 1, for example, as shown in Figure 9. In the manner described above, new plastic pipes 6 are successively introduced from the inlet side vertical hole 3 into the existing piping 1, and the fused plastic pipes 6 are successively fed out toward the outlet side vertical hole 4. Each time a new plastic pipe 6 is fed out, it is fused below the inlet side vertical hole 3, and multiple plastic pipes 6 fused via the electric fusion joints 30 can be continuously installed inside the existing piping 1 extending from the outlet side vertical hole 4 to the inlet side vertical hole 3.

[0058] FIG. 8 shows a drawing device H suitable for use when sliding a plurality of joined resin pipes 6 within an existing piping 1. In FIG. The lead-in device H shown in Fig. 8 includes a winch device 20 housed in the outlet-side vertical hole 4 and a lead-in wire (wire) 22 of a predetermined length wound around a winding drum 21 of the winch device 20. The tip side of the lead-in wire 22 is connected to the leading resin pipe 6 of the resin pipes 6 which are joined together by fusion. In the rehabilitation work of the existing pipe 1, for example, after the outlet side vertical hole 4 and the inlet side vertical hole 3 are formed, the winch device 20 is installed on the bottom side of the outlet side vertical hole 4. Then, the lead-in wire 22 of the winch device 20 is pulled out from the winding drum 21 so that the tip of the lead-in wire 22 reaches the lower side of the inlet side vertical hole 3, and the tip of the lead-in wire 22 is attached to the leading plastic pipe 6 to be connected in a multiple-extension manner. When connecting multiple plastic pipes 6 in a multiple-extension manner, the leading plastic pipe 6 is pulled by the lead-in wire 22 of the winch device 20 while sliding it within the existing pipe 1, whereby the extended plastic pipe 6 can be easily moved along the existing pipe 1.

[0059] When the leading resin pipe 6 that was fused first reaches the resin pipe 6 in the outlet-side vertical hole 4 as shown in Fig. 10, the ends 6a of the two adjacent resin pipes 6 are made to face each other. In this state, the ends 6a of the two resin pipes 6 located below the outlet-side vertical hole 4 are positioned to face each other using a support 13 or the like. Thereafter, the two adjacent resin pipes 6 below the outlet-side vertical hole 4 are fused according to the fusion procedure using the electric fusion joint 30 previously described with reference to Figs. 5 to 7. By the above-mentioned work, the pipe renewal work using a plurality of resin pipes 6 for the existing piping 1 between the inlet side vertical hole 3 and the outlet side vertical hole 4 can be completed.

[0060] After completing the pipeline rehabilitation work of the existing piping 1 by extending and connecting a plurality of plastic pipes 6 from the position of the outlet side vertical hole 4 to the position of the inlet side vertical hole 3, the pipeline rehabilitation work of the remaining area is carried out. That is, the pipeline rehabilitation work of the area to the right of the inlet side vertical hole 3 shown in FIG. 10 is carried out. To achieve this, an additional entrance side vertical hole 5 and an additional entrance side work opening 1c are formed not between the exit side vertical hole 4 and the entrance side vertical hole 3, but on the opposite side of the exit side vertical hole 4 when viewed from the entrance side vertical hole 3 (to the side of the entrance side vertical hole 3 in Figure 10). The work so far has involved introducing a plastic pipe 6 starting from the inlet vertical hole 3 toward the outlet vertical hole 4, thereby rehabilitating the existing piping 1. In the next stage, an additional entrance side pit 5 is formed at a position opposite to the side facing the exit side pit 4 from the entrance side pit 3 previously used as the starting point, and at a predetermined distance from the entrance side pit 3 used as the starting point.

[0061] 2 shown above shows a state in which an additional inlet-side pit 5 has been formed in advance at a position separated from the inlet-side pit 3 in the early stages of rehabilitation work. The additional inlet-side pit 5 may be formed in the early stages of rehabilitation work, or after all the plastic pipes 6 have been laid between the inlet-side pit 3 and the outlet-side pit 4 as shown in FIG. 10, or during the intermediate stage of extending and connecting the plastic pipes 6 between the inlet-side pit 3 and the outlet-side pit 4. In the work up to now, the plastic pipe 6 has been installed by sequentially extending from the inlet side vertical hole 3 toward the outlet side vertical hole 4, but in the work to come, it will be necessary to install a plastic pipe 6 between the additional inlet side vertical hole 5 and the inlet side vertical hole 3 that was previously the starting point.

[0062] In the subsequent work, the inlet side shaft 3 that was previously used as the starting point is regarded as the outlet side shaft, and multiple plastic pipes 6 are sequentially introduced into the existing piping 1 from the additional inlet side shaft 5. Then, multiple plastic pipes 6 are spliced ​​and connected below the additional inlet side shaft 5, and are sequentially sent to the inlet side shaft 3 side. When the head of the spliced ​​plastic pipe 6 reaches the plastic pipe 6 below the inlet side shaft 3, the ends of the plastic pipes 6, 6 that have reached and are facing each other are fused together, as previously explained based on FIG. 10. By these work, multiple plastic pipes 6 can be arranged between the bottom of the additional inlet side shaft 5 and the inlet side shaft 3, and the pipeline rehabilitation of the existing piping 1 in this area is completed. As described above, by forming additional inlet side vertical holes 5 successively and intermittently along the length of the existing pipe 1, the entire pipe line can be rehabilitated for the corresponding length of the existing pipe 1.

[0063] In the example described with reference to Figures 1 to 10, the existing pipe 1 is long. However, when the existing pipe 1 is relatively short, it can be dealt with by providing an outlet side vertical hole 4 at one end in the length direction of the existing pipe 1 to be rehabilitated, and providing an inlet side vertical hole 3 at the other end in the length direction. In this case, the plastic pipe 6 is sequentially introduced from the inlet side vertical hole 3 to extend and connect the plastic pipe 6, and when the tip of the extended plastic pipe 6 reaches the outlet side vertical hole 4, the rehabilitation work of the existing pipe 1 is completed. In addition, in the case of sewer pipes, there may be a structure in which the direction of the sewer pipe changes at the location of a manhole. In this case, it is possible to deal with this by forming an outlet side vertical hole 4 or an inlet side vertical hole 3 at the location of one manhole, and forming an inlet side vertical hole 3 or an outlet side vertical hole 4 at the location of another manhole. Therefore, the rehabilitation work of existing piping described above can also be applied to the rehabilitation of existing piping that has a bent route through a manhole.

[0064] <Second embodiment> 11 to 14 show the structure of an electric fusion joint and a resin pipe for constituting a rehabilitation pipe according to a second embodiment suitable for use in rehabilitation of an existing pipe 1. FIG. The electric fusion joint 70 according to the second embodiment has a cylindrical resin pipe body 73 having joint spigots 71, 72 that can be inserted into the inside of the resin pipes 6, 6 to be fused. A ring-shaped stopper 75 is formed in the center of the resin pipe body 73 in the longitudinal direction, and the joint spigots 71, 72 are formed so as to be located at both ends in the longitudinal direction. The resin pipe body 73 is made of the same material as the material constituting the resin pipe body 50 of the electric fusion joint 30 described above. Therefore, the resin pipe body 73 is made of a polyolefin resin. Stopper 75 is formed between fitting spigot portion 71 and fitting spigot portion 72, and has outer circumferential surface 75a protruding a predetermined height from the outer circumferential surfaces of fitting spigot portion 71 and fitting spigot portion 72. As an example, as shown in Figure 11 etc., when fitting spigot portion 71 and fitting spigot portion 72 are inserted into plastic pipes 6, 6, outer circumferential surface 75a protrudes slightly outward from the outer circumferential surfaces of plastic pipes 6, 6. The pipe end of plastic pipe 6 on the side into which fitting spigot portion 71 is inserted comes into contact with stopper 75 to determine the insertion position, and the pipe end of plastic pipe 6 into which fitting spigot portion 72 is inserted comes into contact with stopper 75 to determine the insertion position, making it possible to regulate the positions of each pipe end.

[0065] A spiral groove (not shown in the figure) is formed on the outer circumferential surface of the joint spigot portions 71, 72 to have a predetermined width along the outer circumferential surface of the joint spigot portions 71, 72. Heating wires 76, 77 are wound along the spiral groove. 14, the winding start end of heating wire 76 on the outer periphery of joint insertion portion 71 is located close to stopper 75. The winding turn-back end is the tip side of joint insertion portion 71, and the winding end is located close to stopper 75. The start end and end end of heating wire 76 each extend toward stopper 75 and are connected to terminals 80, 81 formed to protrude from the outer periphery of stopper 75.

[0066] 14, the winding start end of heating wire 77 on the outer periphery of joint insertion portion 72 is located close to stopper 75. The winding turn-back end is the tip side of joint insertion portion 72, and the winding end is located close to stopper 75. The start and end sides of heating wire 77 extend toward stopper 75 and are connected to terminals 82, 83 that are formed to protrude from the outer periphery of stopper 75. In the resin pipe main body 73 shown in FIG. 14, the side where the heating wire 76 is provided constitutes a first heating portion 76A, and the side where the heating wire 77 is provided constitutes a second heating portion 77A.

[0067] The connection lines 34, 34 of the controller 33 described above with reference to Fig. 6 can be connected to the terminals 80, 81. The connection lines 34, 34 of the controller 33 described above with reference to Fig. 6 can be connected to the terminals 82, 83. Figures 11 and 12 show a state in which only one of the fitting mouth portions 71, 72 is inserted into the end portion 6a of the plastic pipe 6, but to extend and fuse the plastic pipes 6, 6, both fitting mouth portions 71, 72 are inserted into the end portion 6a of the plastic pipe 6.

[0068] In this state, a predetermined amount of electricity is applied from the controller 33, and when it is cooled after application of electricity, the outer peripheral surfaces of the joint socket portions 71, 72 and the inner peripheral surface of the end of the plastic pipe 6 are fused to each other, fusing the plastic pipes 6, 6. The plastic pipe body 73 and the plastic pipe 6 are fused to each other at the first heating portion 76A provided with the heating wire 76, and the plastic pipe body 73 and the plastic pipe 6 are fused to each other at the second heating portion 77A provided with the heating wire 77. By using the electric fusion joint 70 of the second embodiment to extend and connect a plurality of plastic pipes 6 and housing them inside the existing piping 1, the line of the existing piping 1 can be rehabilitated.

[0069] <Third embodiment> 15 to 17 show a resin pipe equipped with an electric fusion joint for constituting a rehabilitation pipe according to a third embodiment suitable for use in rehabilitation of an existing pipe 1. FIG. In the third embodiment, a reduced diameter section 92 is formed at one end in the longitudinal direction of a plastic tube 91, and an electric fusion joint 93 is incorporated at the tip side of this reduced diameter section 92. A receiving opening 94 into which the reduced diameter section 92 can be inserted is formed at the other end in the longitudinal direction of the plastic tube 91. The plastic tube 91 is made of polyolefin-based resin, as in the previous embodiment.

[0070] A heating wire 95 is wound around the outer circumferential surface of the reduced diameter portion 92 along the length of the reduced diameter portion 92 to a predetermined width. A helical groove (not shown) is formed on the outer circumferential surface of the reduced diameter portion 92 in the region where the heating wire 95 is wound, and the heating wire 95 is wound along this helical groove. On the tip side of the reduced diameter portion 92, the part around which the heating wire 95 is wound is a small diameter portion 92a having the same inner diameter and outer diameter. In contrast, on the base end side of the reduced diameter portion 92, a slope portion 92b is formed in which the outer circumferential surface is gradually narrowed to form a tapered shape. Terminals 97, 98 are formed so as to protrude from the outer circumferential surface of the receiving opening 94 of the resin pipe 91. These terminals 97, 98 are formed so as to penetrate the receiving opening 94 in the thickness direction and to protrude slightly on the inner and outer surfaces of the receiving opening 94, respectively.

[0071] 17, two plastic pipes 91 are prepared, and the reduced diameter section 92 of one plastic pipe 91 is inserted into the receiving opening 94 of the other plastic pipe 91, thereby allowing the two plastic pipes 91 to be joined together. At the tip side of the reduced diameter section 92, the entire small diameter section 92a is inserted into the receiving opening 94. However, because the base end side of the reduced diameter section 92 forms a sloped section 92b, when the sloped section 92b is inserted partway into the receiving opening 94, the reduced diameter section 92 cannot be inserted any further. When the reduced diameter portion 92 is inserted into the receiving opening 94 of the resin pipe 91 as described above, the terminals 97, 98 are aligned with a part of the heating wire 95 and are electrically connected thereto.

[0072] Since the resin pipe 91 of the third embodiment has a heating wire 95 in the reduced diameter section 92, the reduced diameter section 92 can be inserted into the socket opening 94, and the controller 33 can be connected to the terminals 97 and 98 in the same manner as in the fusion operation described above with reference to Figure 6. Then, electricity is passed from the controller 33 to the heating wire 95 to generate heat, thereby fusion-splicing the resin pipes 91, 91.

[0073] In the structure of the third embodiment, the terminal pins constituting the terminals 97, 98 can be configured to be freely removed from the surface of the plastic pipe 91. In this case, when the terminal pins are removed after fusion, there is no portion protruding from the outer surface of the plastic pipe 91. In the structure of the third embodiment, the reduced diameter portion (slope portion 92b) in the reduced diameter portion 92 can be made as short as possible, which makes it easy to ensure a flow rate.

[0074] <Fourth embodiment> FIG. 18 shows a resin pipe equipped with an electric fusion joint for constituting a rehabilitation pipe according to a fourth embodiment suitable for use in rehabilitation of an existing pipe 1. In FIG. In the fourth embodiment, the regeneration pipe 100 has a resin pipe 104 equipped with a reducer pipe 103 via a butt fusion part 102 at one end in the longitudinal direction. The regeneration pipe 100 further has a cylindrical electric fusion joint 105 into which the tip of the reducer pipe 103 can be inserted, and a resin pipe 107 fused to the electric fusion joint 105 via a butt fusion part 106. The electric fusion joint 105 has a cylindrical plastic tube body 108 into which the tip of the reducer tube 103 can be inserted, and a spiral groove (not shown) is formed on the inner surface of this plastic tube body 108, and an electric heating wire (not shown) is provided along this spiral groove. The reducer pipe 103, the resin pipe 104, the resin pipe 107, and the resin pipe main body 108 are preferably made of polyolefin resin, as in the previous embodiment.

[0075] The butt fusion parts 102, 106 are fusion parts formed by butting together the parts of the plastic pipes to be fused while they are heated with a heater to a temperature above the softening point and below the melting point. The plastic pipes are heated and held for a predetermined time while a constant pressure is applied in the butting direction, and then cooled to form a butt fusion part. Butt fusion requires special equipment and only a limited number of contractors are able to carry it out, but if the conditions are prepared in advance in a factory or the like, the plastic pipes can be reliably fused and joined together. In addition, for the butt fused portions 102, 106, the outer surface beads protruding from the outer periphery of the resin pipes 104, 107 can be cut off to facilitate insertion of the rehabilitation pipe into the existing pipe.

[0076] The electric fusion joint 105 has a spiral groove on the inner peripheral surface of a plastic pipe body 108, and a heating wire (not shown) is provided along this spiral groove to form a heat generating portion. The plastic pipe body 108 is provided with terminals 110 and 111 each having a terminal pin that penetrates the plastic pipe body 108 in the thickness direction.

[0077] In the structure of the fourth embodiment, the tip of the reducer pipe 103 is inserted into the plastic pipe main body 108, and the controller 33 shown in Fig. 6 is connected to the terminals 110 and 111, and the necessary power is applied to the heating wire to generate heat. When the power application is stopped and the wire is cooled, a rehabilitation pipe can be obtained in which the plastic pipe 104 and the plastic pipe 107 are joined to the reducer pipe 103 via the electric fusion joint 105, as shown in Fig. 18. A plurality of resin pipes 104 equipped with reducer pipes 103 and resin pipes 107 equipped with electric fusion joints 105 are prepared. The tip of the reducer pipe 103 is inserted into the electric fusion joint 105 at the site, and a procedure similar to that described above with reference to Figures 2 to 10 is carried out, and a rehabilitating pipeline can be formed inside the existing piping 1 by sequentially adding on the pipes.

[0078] In the structure of the fourth embodiment, the pipe end of the resin pipe 104 is reduced in diameter via a reducer pipe 103 and connected to an electric fusion joint 105. This makes it possible to minimize the pressure loss of the fluid flowing inside, and makes it easy to ensure the flow rate.

[0079] The existing pipe 1 and the rehabilitation pipeline 2 described above have both been described as examples of pipes that are buried underground, but the present invention can also be applied to cases where the existing pipe 1 is not underground but is installed under a structure or along a bridge, etc. As described above, even if a site does not allow for wide-area excavation along the existing pipe 1, the present invention can be applied without any problems as long as it is possible to form an inlet side vertical hole 3 and an outlet side vertical hole 4, or an additional inlet side vertical hole 5 in addition to these.

[0080] <Fifth embodiment> 19 and 20 show a resin pipe 120 and an electric fusion joint 121 for constituting a rehabilitation pipe according to a fifth embodiment suitable for use in rehabilitation of an existing pipe 1. FIG. In the fifth embodiment, the resin pipe 120 has a pipe body 120A and small diameter portions 120B formed on both ends of the pipe body 120A in the longitudinal direction, and an electric fusion joint 121 is attached to the small diameter portions 120B. The resin pipe 120 is made of a polyolefin resin, similar to the resin pipe 6 of the previous embodiment.

[0081] 19, the electric fusion joint 121 is a socket-type joint having openings 122b, 122d at both ends. Both ends of the electric fusion joint 121 are sockets. The electric fusion joint 121 includes a resin tube main body 122, a stopper (protrusion) 123, a first heating wire 124A, a second heating wire 124B, two first screw portions 125A, two second screw portions 125B, two first terminal units 126A, and two second terminal units 126B. 19 shows only one each of the first screw portion 125A, the second screw portion 125B, the first terminal unit 126A, and the second terminal unit 126B, but in reality, two each of these are formed spaced apart in the circumferential direction of the resin pipe main body 122. The electric fusion joint 121 does not necessarily have to have the stopper 123.

[0082] The resin pipe main body 122 is formed in a cylindrical shape, and the stopper 123 is formed in an annular shape protruding from the inner peripheral surface of the resin pipe main body 122. In the following, the central axes of the resin pipe main body 122 and the stopper 123 are expressed as an axis O1 as a common axis. The stopper 123 is formed at the position of a center line S1 drawn in the center of the resin pipe main body 122 in the longitudinal direction so as to protrude one step from the inner peripheral surface of the resin pipe main body 122. The electric fusion joint 121 is disposed inside the existing piping 1 shown in the previous embodiment. The shape of the resin pipe body 122 is not limited to a cylindrical shape, and may be a square tube shape or the like.

[0083] A first opening 122b is formed at a first end 122a of the resin pipe body 122, and a second opening 122d is formed at a second end 122c. A first heating wire 124A (first heating portion) is provided on the inner surface of the resin pipe main body 122 between the first end 122a and the stopper 123, and a second heating wire (second heating portion) 124B is provided on the inner surface of the resin pipe main body 122 between the second end 122c and the stopper 123.

[0084] The two first screw portions 125A are made of metal tubes and are spaced apart circumferentially around the outer periphery of the resin pipe main body 122, with one first screw portion 125A electrically connected to one end of the first heating wire 124A and the other first screw portion 125A electrically connected to the other end of the first heating wire 124A. The first terminal 129A is formed of a metal rod-shaped member, and is screwed into the first screw portion 125A by a screw portion formed on the outer circumferential surface of the first terminal 129A. One of the first terminals 129A is detachably attached to one end of the first heating wire 124A via one of the first screw portions 125A. The other of the first terminals 129A is detachably attached to the other end of the first heating wire 124A via the other of the first screw portions 125A.

[0085] The first protective member 130A is formed in a cylindrical shape with a bottom, and has a peripheral wall 131A and a bottom wall 132A. The peripheral wall 131A is disposed so as to protrude from the outer peripheral surface of the resin pipe main body 122 coaxially with the first terminal 129A. The outer diameter of the peripheral wall 131A gradually increases as it approaches the outer peripheral surface of the resin pipe main body 122. The inner diameter of the peripheral wall 131A is constant regardless of the radial position of the resin pipe main body 122. The peripheral wall 131A protrudes radially outward from the resin pipe main body 122. The peripheral wall 131A surrounds the first terminal 129A. The peripheral wall 131A may be formed in an angular cylindrical shape such as a rectangular cylindrical shape or a polygonal cylindrical shape. The bottom wall 132A is formed in an annular shape. The bottom wall 132A protrudes from a radially inner end of the peripheral wall 131A toward the first terminal 129A. The protruding tip of the peripheral wall 131A is fixed to the first terminal 129A.

[0086] The structure of the portion where the second screw portion 125B is formed is the same as the portion where the first screw portion 125A is formed. Of the two second screw portions 125B, one is connected to one end of the second heating wire 124B, and the other is connected to the other end of the second heating wire 124B. A second terminal 129B is connected to the second screw portion 125B, and a second protective member 130B is provided to surround the second terminal 129B. The second protective member 130B has a peripheral wall 131B and a bottom wall 132B.

[0087] In the structure of the fifth embodiment, the small diameter portions 120B of the two plastic pipes 120 are arranged facing each other as shown in Fig. 20. Then, the small diameter portion 120B of one plastic pipe 120 is inserted into one opening 122b of the electric fusion joint 121, and the small diameter portion 120B of the other plastic pipe 120 is inserted into the other opening 122d.

[0088] Next, the terminals 52, 53 or the terminals 57, 58 of the controller 33 described above with reference to Figures 4 to 6 are connected to the two first terminals 129A and the two second terminals 129B, respectively, and electricity is passed through them. This causes the first heating wire 124A and the second heating wire 124B to generate heat, making it possible to electrically fuse the plastic pipes 120, 120 in the same manner as in the previous embodiment. In the structure of the fifth embodiment, a required number of resin pipes 120 having small diameter portions 120B on both ends are prepared, and these small diameter portions 120B can be joined together in sequence using electric fusion joints 121. By utilizing the structure of the fifth embodiment, the existing pipe 1 can be rehabilitated in the same manner as the structure of the previous first embodiment.

[0089] The electric fusion joint 121 may have an indicator 140. The indicator 140 has a known configuration. For example, after fusion, this indicator protrudes radially outward from the plastic pipe main body 122, making it possible to check whether fusion has been performed reliably. In order to make the color of the indicator 140 easily visible even in a dark installation space, the color of the indicator 140 may be different from the color of the resin pipe main body 122. The color of the indicator 140 may be colored by coloring, printing, imprinting, or the like, and the color of the indicator 140 may be a fluorescent color, or the like.

[0090] Also, the first screw portion 125A, the first terminal 129A, and the first protective member 130A may be formed in an L-shape, and 129A may be configured to face horizontally in the longitudinal direction of the resin tube 120. A configuration can be adopted in which the terminals 52 and 53 or the terminals 57 and 58 of the controller 33 are connected to the horizontally oriented first terminal 129A.

[0091] Sixth embodiment 21 and 22 show a resin pipe 150 and an electric fusion joint 121 for constituting a rehabilitation pipe according to a sixth embodiment suitable for use in rehabilitation of an existing pipe 1. FIG. In the structure of the sixth embodiment, what is connected using the electric fusion joint 121 is a resin tube 150 having a tube body 150A with a reduced diameter section 150B and a short tube section 150C at both ends. The reduced diameter section 150B constitutes a reducer tube with a tapered tip, and the short tube section 150C is a tube for fusion splicing having the same inner diameter.

[0092] In the structure of the sixth embodiment, the short pipe portions 150C of two plastic pipes 150 are arranged facing each other as shown in Fig. 21. Then, as shown in Fig. 22, the short pipe portion 150C of one plastic pipe 150 is inserted into one opening 122b of the electric fusion joint 121, and the short pipe portion 150C of the other plastic pipe 150 is inserted into the other opening 122d. Next, the terminals 52, 53 or the terminals 57, 58 of the controller 33 described above with reference to Figures 4 to 6 are connected to the two first terminals 129A and the two second terminals 129B, respectively, and electricity is passed through them. This causes the first heating wire 124A and the second heating wire 124B to generate heat, and the resin pipes 150, 150 can be electrically fused together in the same manner as in the previous embodiment. In the structure of the sixth embodiment, a required number of resin pipes 150 having small-diameter short pipe sections 150C at both ends are prepared, and these short pipe sections 150C can be joined together in sequence using electric fusion joints 121. By utilizing the structure of the sixth embodiment, the existing pipe 1 can be rehabilitated in the same manner as the structure of the previous first embodiment.

[0093] Seventh embodiment FIG. 23 shows a resin pipe 160 and an electric fusion joint 161 for constituting a rehabilitation pipe according to a seventh embodiment, which is suitable for use in rehabilitation of the existing pipe 1. In FIG. The resin pipe 160 used in this embodiment has a pipe body 160A, one end of which is formed with a small diameter portion 160B, and the other end of the pipe body 160A is integrated with an electric fusion joint 161. The electric fusion joint 161 of this embodiment is composed of only the components of the electric fusion joint 121 previously described with reference to Figures 19 and 20, from the position where the stopper 123 is formed to the second end 122c side. That is, the electric fusion joint 161 has a cylindrical joint pipe body 162, a second heating wire 124B, two second screw portions 125B, two second protective members 130B, two second terminals 129B, and two second terminal units 126B. The joint pipe body 162 has a length that allows the small diameter portion 160B of the resin pipe 160 to be freely inserted therein.

[0094] A joint pipe body 162 of an electric fusion joint 161 is integrated with the other end side of the plastic pipe 160. Therefore, by inserting the small diameter portion 160B of one plastic pipe 160 into the joint pipe body 162 of the other plastic pipe 160, two plastic pipes 160 can be connected. In the structure of the seventh embodiment, the small diameter portion 160B of one plastic pipe 160 is inserted into the joint pipe body 162 of the other plastic pipe 160, and the terminals 57, 58 of the controller 33 previously described with reference to Figures 4 to 6 are connected to the two second terminals 129B, respectively, and electricity is passed through. This causes the second heating wire 124B to heat up, and the plastic pipes 160, 160 can be electrically fused together in the same manner as in the previous embodiment. In the structure of the seventh embodiment, the required number of plastic pipes 160 having small diameter portions 160B and electric fusion joints 161 are prepared, and these small diameter portions 160B can be sequentially inserted into the electric fusion joints 161 of other plastic pipes 160 and electrically fused to extend and connect them. By utilizing the structure of the seventh embodiment, the existing pipe 1 can be rehabilitated in the same manner as the structure of the previous first embodiment.

[0095] Eighth embodiment FIG. 24 shows a plastic pipe 150 and a plastic pipe 170 equipped with an electric fusion joint 161 for constituting a rehabilitation pipe according to an eighth embodiment suitable for use in rehabilitation of an existing pipe 1. In FIG. The resin pipe 150 is a resin pipe having a configuration similar to that of the resin pipe 150 described with reference to Figures 21 and 22. In the eighth embodiment, the electric fusion joint 161 is integrally provided at one end of a pipe main body 170A.

[0096] In the structure of the eighth embodiment, the short pipe portion 150C of the resin pipe 150 is inserted into the joint body 166 of the electric fusion joint 161 as shown in FIG. Next, the terminals 52, 53 or the terminals 57, 58 of the controller 33 described above with reference to Figures 4 to 6 are connected to the two second terminals 129B, respectively, and electricity is passed through them. This causes the second heating wire 124B to generate heat, making it possible to electrically fuse the plastic pipes 150, 170 in the same manner as in the previous embodiment. In the structure of the eighth embodiment as well, the resin tube 170 having the electric fusion joint 161 and the resin tube 150 can be joined together. By utilizing the structure of the eighth embodiment, the existing pipe 1 can be rehabilitated in the same manner as the previous structures. [Explanation of symbols]

[0097] 1...Existing piping, 2...Rehabilitation pipeline (newly installed piping section), 3... Entrance side pit, 4...Exit side pit, 5…Additional entrance shaft, 6...Resin pipe, 7...Fusion part, 30... Electric fusion joint, 50...Resin pipe body, 50A, 50B...Joint socket, 51...first heating portion, 55, 59…indicator, 56...second heating section, 61, 62...Heating wire, 70... Electric fusion joint, 71, 72...Joint spigot portion, 73...Resin pipe body, 76, 77...heating wire, 76A…First heating section, 77A: Second heating section, 93... Electric fusion joint, 95...Heating wire, 103...reducer tube, 105... Electric fusion joint, 108...Resin pipe body, 120...plastic pipe, 121... Electric fusion joint, 122...Resin pipe body, 123…Stopper, 124A...1st heating wire, 124B…Second heating wire, 140…indicator, 150…Resin pipe, 160…Resin pipe, 161, 165... Electric fusion joint, 170...Plastic pipe.

Claims

1. A rehabilitation pipe for rehabilitating an existing pipe, The electric fusion joint is accommodated in the existing piping and includes a plurality of resin pipes made of polyolefin resin and a resin pipe body that joins the plurality of resin pipes, The diameter reduction rate expressed by the relationship (outer diameter of the resin pipe / inner diameter of the existing piping) is 35% or less. Rehabilitation piping.

2. The electric fusion joint is a cylindrical resin pipe body having a joint receiving portion at both ends in a longitudinal direction into which the end of the resin pipe can be inserted; A first heating portion having a heating wire arranged on an inner peripheral surface side of one of the joint socket portions; A second heating portion having a heating wire arranged on the inner circumferential surface side of the other joint socket portion, The rehabilitation pipe according to claim 1.

3. The electric fusion joint is a cylindrical resin pipe body having a joint spigot portion at both ends in a longitudinal direction thereof that can be inserted into the inside of the resin pipe; a stopper formed on an outer surface of the plastic pipe body so as to protrude outward, the stopper being capable of regulating an insertion position of the pipe end of the plastic pipe when the joint spigot portion is inserted into the inside of the plastic pipe; A first heating portion having a heating wire disposed at one of the joint spigots; A second heating portion having a heating wire arranged in the other joint spigot portion, The rehabilitation pipe according to claim 1.

4. an electric fusion joint having a resin pipe body that receives the tip side of the reducer pipe; a resin pipe connected to a rear end side of the reducer pipe; a resin tube connected to the other end of the electric fusion joint, A heating unit having an electric heating wire provided on the inner circumferential side of the resin pipe body is provided. The rehabilitation pipe according to claim 1.

5. A terminal connected to the heating wire is provided on the outer periphery of the resin pipe body. The rehabilitation pipe according to claim 2 or 4.

6. A terminal connected to the heating wire is provided on the outer periphery of the stopper. The rehabilitation pipe according to claim 3.

7. An indicator for confirming fusion is provided on the outer periphery of the resin pipe body. The rehabilitation pipe according to claim 2 or 4.

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