JP2008075809A - Road heating pipe connection structure, and anticorrosive sleeve to be used for the same and connection method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a road heating pipe connection structure achieving a longer life by improving snow melting efficiency (fuel economy), constructing efficiency, and a facility life, and by applying complete anticorrosive measures to a heat radiating circuit. <P>SOLUTION: The pipe connection structure is provided for a road heating 7 which constructs the heat radiating circuit for circulating heat medium in metal pipes 1, 2 connected to each other at a proper length and embedded. It comprises: a plurality of resin coated metal pipes 1j, 2j formed by applying resin coats to the outer peripheries of the metal pipes 1, 2; a resin sleeve 3 into which the single-side ends of a connection portion between the resin coated metal pipes are fitted through both sides to form a liquid-tight joint; a metal sleeve 4 for covering the resin sleeve at its outer periphery and firmly compression-bonding and holding it; and a thermally contracted tube 5 for covering the metal sleeve. The single-side ends fitted into the resin sleeve through both ends to face each other are held at a predetermined interval. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pipe connection structure for hot water type load heating, a corrosion prevention sleeve, and a connection method therefor, and more particularly, a pipe structure for connecting a plurality of resin-coated metal pipes constituting a heat dissipation circuit while preventing electric corrosion, and a corrosion prevention used for the pipe structure. The present invention relates to a sleeve and a connection method using the sleeve.

  In hot water type road heating (hereinafter simply abbreviated as “road heating”), a heat radiation pipe is embedded in a structural layer such as concrete or asphalt close to the surface layer of the roadbed to increase the heat exchange efficiency. The snow is melted by transferring heat to the roadbed. However, when a metal pipe is used as the heat radiating pipe, it is inevitable that the metal pipe rusts and corrodes and has a short life unless some anticorrosion measures are taken. The difficulty of short-term maintenance due to this rust / corrosion is the reason why it is difficult to adopt a metal tube as a heat-radiating tube for load heating.

  The main cause of metal rusting and corrosion is electrochemical corrosion (hereinafter referred to as “electric corrosion”). Electrolytic corrosion means that when two different metals come into contact with the electrolyte solution at the same time, the electrons move from a metal with a strong tendency to ionize to a weak metal due to the potential difference between the metals, and the metal atoms that have lost their charge dissolve in the solution as ions. This is a phenomenon in which the metal corrodes when released. In addition, when connecting a plurality of metal pipes for a long time, even if they are between the same type of metal, a certain amount of electrolytic corrosion will occur at the connection part. In that case, the connection part should be electrically insulated. It is thought that there is a corrosion protection effect.

  In fact, when metal steel pipes are buried without resin coating, the flow of metal ions through water components such as soil groundwater or concrete, leakage currents leaking from DC rails, and other weak currents There is erosion. The chemical reaction with acid / alkali is considered to be similar to electric corrosion, and it is extremely difficult to eliminate the factors of rust and corrosion caused by electric corrosion.

  In addition, unless the cause of galvanic corrosion is eliminated, the metal melts rapidly in response to the natural phenomenon of electricity flowing through the surface of the buried metal. As a countermeasure, for example, an iron structure coated with a corrosion-resistant paint containing zinc or the like and exhibiting a rust prevention effect is often used. Even such a hot-dip galvanized iron material or the like will be corroded by electric corrosion as long as it is always in a humid state or a condition in which wetting and drying are repeated, like a heat-radiating tube for load heating.

  For this reason, in general road heating, non-metallic materials that are unrelated to electric corrosion are used as heat dissipating piping (hereinafter referred to as “radiating tubes” or “radiating circuits”) that are buried and used. That is, a crosslinked polyethylene pipe, which is a kind of thermoplastic plastic, is frequently used.

  The cross-linked polyethylene refers to an ultra-high molecular weight polyethylene having a three-dimensional network structure by connecting molecules of chain structure polyethylene as a thermoplastic plastic at various places. Accordingly, since the polyethylene has a three-dimensional network structure like a thermosetting resin when the crosslinking reaction is completed, both heat resistance and creep performance (described later) are improved.

  Originally, raw material polyethylene has advantages such as light specific gravity, flexibility, corrosion resistance, impact resistance, low temperature characteristics, and good electrical characteristics (not subject to electric corrosion). These advantages are further improved by crosslinking. In particular, ESC (environmental stress cracking), creep performance, chemical resistance, and heat aging resistance are improved.

  The creep performance is the most important index representing the life and strength of a plastic tube, and indicates a practical strength against creep. Creep means a phenomenon in which deformation with time load on plastic increases.

  If the operating temperature of the cross-linked polyethylene pipe is set to 95 ° C or lower, there will be no generation of bending points over a long period of time, and this characteristic is markedly different from other plastics for piping materials, which is well known in various literatures and standard data. It is.

  Although this cross-linked polyethylene pipe has the above-mentioned advantages, its thermal conductivity λ is as low as about 0.3 [W / mK], and when applied to a heat-radiating pipe for load heating, it is heated from a heat medium. Since the heat exchange efficiency to the roadbed is poor, there is a drawback that some extra fuel consumption such as a hot water boiler is required.

  Note that the thermal conductivity λ here is a physical quantity that quantitatively indicates the ease of heat transmission, also called thermal conductivity, and in heat conduction, heat flux density (heat energy that passes through a unit area per unit time). This is a value obtained by dividing J by the temperature gradient gradT. The SI unit of this thermal conductivity λ is [W / mK], and [W / cmK] is also used.

Thermal conductivity λ = −J / gradT
Heat flux density J = -λgradT
λ: thermal conductivity, J: heat flux density, T: temperature, grad T: temperature gradient

  By the way, the thermal conductivity λ [W / mK] value around room temperature of a general material is the highest value of 420, copper 390, gold 320, aluminum 236, silicon 168, iron 84, platinum 70, crystal 8 , Glass 1, water 0.6, wool 0.05, expanded polystyrene (Styrofoam) 0.03, and so on.

  For this reason, road heating with a heat-dissipating circuit using cross-linked polyethylene pipes has the advantages of easy construction and long service life in terms of processability, strength, chemical resistance, electrical insulation, etc. However, the fuel efficiency is poor.

  As described above, in the case of a crosslinked polyethylene pipe, the low thermal conductivity λ = about 0.3 [W / mK] is a cause of deterioration in fuel consumption. In that respect, the heat conductivity λ of a metal tube, for example, a stainless steel tube, a steel tube, an aluminum tube, a copper tube, etc., that is considered to have good heat exchange efficiency is about 15 to 370 (copper 401 depending on the material) [W / mK]. Yes, it has a thermal conductivity λ of about 50 to 1000 times that of crosslinked polyethylene.

  And as a technique to improve snow melting efficiency and workability, which is a common problem with road heating, in addition to the method of spreading the heat insulation material under the heat radiation pipe, heating with a foam heat insulation material attached to the heat radiation pipe A construction method and a heat radiating pipe are known (Patent Document 1).

  On the other hand, as a technology related to the problem of preventing electrolytic corrosion of piping, there are a corrosion prevention sleeve to be mounted to prevent corrosion of a cutting surface and the like, a mounting tool for the corrosion protection sleeve, and a mounting method for the corrosion protection sleeve when installing water pipes and the like. Known (Patent Document 2).

  The sleeve body is a rubber sleeve in which a resin sleeve having good sliding characteristics and large elongation characteristics is inserted on the inner diameter side of the rubber sleeve. By inserting the metal sleeve, the diameter of the resin sleeve is expanded and, at the same time, the rubber sleeve is expanded. This resin sleeve is provided with a flange on the upper end, a tapered portion on the inner peripheral surface of the opening of the flange, and a protrusion on the inner peripheral surface of the lower end of the resin sleeve.

In addition, there are the following Patent Documents 1 and 2 as known technical documents related to the present invention.
JP-A-11-269809 ([Claims], FIGS. 4 and 5) JP-A-10-306893 ([0012], FIG. 6)

  However, the shape of a rigid, thick metal sleeve such as a rubber sleeve, a resin sleeve, or stainless steel as the anticorrosion sleeve disclosed in Patent Document 2 is a technique suitable for a water pipe or the like, and is not necessarily road load. It is not suitable for ting. Of course, the construction form is completely different.

  Specifically, the lengths of resin-coated metal tubes that are marketed in consideration of efficiency during transportation are, for example, 4 m, 6 m, and 8 m, and connecting means for connecting and extending these as many as appropriate It is necessary to have high performance. That is, there is a problem of quality, cost, and easiness of construction as the performance of the connecting means that secures the total length of the heat radiation circuit by appropriately connecting a number of materials that are actually available at the construction site.

  In view of the above situation, in order to improve the snow melting efficiency (fuel consumption), workability and equipment life, which are common problems in road heating, the present invention adopts a metal tube with high heat exchange efficiency in the heat dissipation circuit, An object of the present invention is to provide a road heating pipe connection structure, a corrosion prevention sleeve used therefor, and a connection method therefor, which are easy to install and have a long service life by taking various anticorrosion measures.

  In order to solve the above-mentioned problems, the invention according to claim 1 is a pipe connection structure of load heating (7) that constitutes a heat dissipation circuit that circulates a heat medium in a metal pipe that is connected to an appropriate length and embedded. And a plurality of resin-coated metal tubes (7c) having a resin coating (1j, 2j) on the outer periphery of the metal tubes (1, 2), and a connection portion (6) of the resin-coated metal tubes (7c). A resin sleeve (3) which inserts one end (1a, 2a) from both sides to form a liquid-tight joint; a metal sleeve (4) which is fitted on the outer periphery of the resin sleeve (3) and held by pressure bonding; A heat-shrinkable tube (5) covering the metal sleeve (4), and the one side ends (1a, 2a) that are respectively inserted and opposed from both ends of the resin sleeve (3) are spaced by a predetermined distance (D). It is characterized by being configured to be held apart only That is a pipe connection structure of the road heating (7).

According to the first aspect of the present invention, the resin-coated metal tube (7c) has better thermal efficiency than the resin tube, and has less electric corrosion.
The resin sleeve (3), which is a joint, is fitted liquid-tightly by fitting one end (1a, 2a) of two resin-coated metal tubes (7c) from both sides. If the one end (1a, 2a) facing each other in the pipe of the resin sleeve (3) is held apart by a predetermined distance (D) by the operator, two resin-coated metal pipes (7c) Electrical insulation is ensured.
If it does so, it will be avoided that it is electrically connected over the full length of the thermal radiation circuit comprised by connecting a some resin coating metal pipe (7c). This prevents the formation of long electrical circuits in the embedded environment and enhances the corrosion protection effect.

The metal sleeve (4) is fitted so as to surround the outer periphery of the resin sleeve (3), and the respective one end (1a, 2a) is firmly pressed and held, so that the connection is not disconnected.
Since the metal sleeve (4) further surrounds the outer periphery of the metal sleeve (4) and is covered with the heat shrinkable tube (5), the outer peripheral surface of the resin-coated metal tube (7c) is waterproofed including the connecting portion (6) and Thus, the metal pipes (1, 2) are not exposed and are electrically insulated.

  In this way, the resin-coated metal tube 7c embedded while retaining electrical insulation has the metal portion embedded because the metal tube (1, 2) is isolated from the acid / alkali component or moisture of the embedded layer. It is possible to prevent the corrosion from proceeding due to the acid / alkali component of the layer.

  In short, in the connection part (6) of the resin-coated metal pipe (7c) that is long connected, the respective one side ends (1a, 2a) are insulated from each other, so that a long electric circuit is formed in the buried layer. You can avoid that. In addition, since the metal pipes (1, 2) constituting the basis of the resin-coated metal pipe (7c) are insulated from the buried layer and the current from the buried layer is cut off, electric corrosion can be prevented.

  The invention according to claim 2 is a corrosion-proof sleeve forming the pipe connection structure of the load heating (7) according to claim 1, and is closely fitted corresponding to the outer diameter of the resin-coated metal tube (7c). A resin sleeve (3) having an inner diameter, a metal sleeve (4) whose outer diameter can be reduced with a crimping tool, and an inner diameter for loosely covering the outer circumference of the reduced-pressure-bonded metal sleeve (4) before thermal contraction And a heat shrinkable tube (5) capable of sealing the entire metal sleeve (4) after heat shrinkage, and at the time of completion of construction, at least the resin sleeve (3), the metal sleeve (4), and the heat shrinkable tube (5) A corrosion-resistant sleeve characterized by being a joint that forms a multilayer structure.

  According to the second aspect of the invention, in addition to the same effects as the first aspect of the invention, since it is possible to deal with easily procured materials and general tools, construction is easy at low cost.

  The invention according to claim 3 is a connection method using the corrosion-resistant sleeve according to claim 2, wherein the resin sleeve (3) having a predetermined length before the two resin-coated metal tubes (7c) are connected. ) And the one end (1a, 2a) are separated by a predetermined distance (D) within the tube of the resin sleeve (3) with the one end (1a, 2a) fitted to each end. A second step of connecting the resin sleeve, a third step of covering the resin sleeve (3) with the metal sleeve (4) having a length close to the resin sleeve (3), and a metal sleeve (4). A connection using a corrosion-resistant sleeve, comprising a fourth step of covering the heat-shrinkable tube (5) so as to be completely covered and then heat-shrinking the heat-shrinkable tube (5). Is the method.

  According to the invention of claim 3, in addition to the same effects as those of the invention of claim 2, because of a small number of man-hours, construction is easy at low cost.

The load heating pipe connection structure according to the present invention, the anticorrosion sleeve used therefor, and the connection method thereby provide the following effects.
1. Snow melting efficiency (fuel consumption) is good.
2. Long life due to anti-corrosion measures.
3. Easy to install at low cost.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an enlarged longitudinal sectional view of a connecting portion of a resin-coated metal tube.
FIG. 2 is a plan view partially showing a construction state of the road heating.
FIG. 3 is an enlarged sectional view taken along line AA in FIG.

First, the present invention will be described from the viewpoint of a load heating pipe connection structure.
The road heating 7 is performed (constructed) immediately below the surface of the target site. As shown in FIG. 3, a protective sheet 7b is stretched on a crushed stone 7a laid in advance, and a resin-coated metal tube 7c is piped in a plane meandering state (FIG. 2) on the upper surface of the protective sheet 7b. Yes.

  Specifically, a mesh 7d is stretched approximately parallel to the upper surface of the meandering resin-coated metal tube 7c with a predetermined interval from the resin-coated metal tube 7c. A concrete 7e is placed on the upper surface of the protective sheet 7b with a predetermined thickness so as to fill the gap with the resin-coated metal tube 7c and the mesh 7d as a core. Furthermore, the construction of the road heating 7 is completed by laminating the asphalt 7f on the upper layer of the concrete 7e. The resin-coated metal tube 7c is connected by a connecting portion 6 (FIGS. 1 and 2).

  In the pipe connection structure of the load heating 7, a heat dissipating circuit that circulates the heat medium through the resin-coated metal pipe 7c that is embedded in an appropriate length is configured. A well-known antifreeze or water is circulated and supplied to the heat radiating circuit with a heating medium (hereinafter referred to as “hot water” including the antifreeze)) heated to an appropriate temperature by a hot water supply boiler (not shown). In addition, if preparation of warm water etc. has already been prepared for other uses, it is often a configuration that uses it.

  The metal pipes 1 and 2 (FIG. 1) constituting the basis of the resin-coated metal pipe 7c (FIGS. 1, 2 and 3) are metal before being connected and constructed by the connecting portion 6, that is, from the material stage. As the resin-coated metal tube 7c with the resin coatings 1j and 2j on the outer circumferences of the tubes 1 and 2, for example, 4m, 6m, and 8m lengths are sold separately. We are using.

  In actual construction, the total length of the heat dissipation circuit is determined according to the size of the target area. Therefore, the one side ends 1a and 2a (FIG. 1) associated with the connecting portions 6 of the plurality of resin-coated metal tubes 7c are fitted from both sides of the resin sleeve 3 which is a joint and are connected in a liquid-tight manner.

  Further, the outer periphery of the resin sleeve 3 after the fitting connection is covered with the metal sleeve 4, and the reduced diameter portions 4a and 4b indicated by the arrows in FIG. ) If it is crimped with a tool, it will be firmly connected and a waterproof seal will be obtained. In addition, it is necessary to prepare by previously fitting the metal sleeve 4 near the connection portion 6 of the resin-coated metal tube 7c.

  Further, the entire metal sleeve 4 is covered with the heat shrinkable tube 5 before heat shrinkage, and then the heat shrinkage is performed. As a result, a completely sealed state is formed. It is necessary to prepare this heat-shrinkable tube 5 by placing it in the vicinity of the connecting portion 6 in advance so that the resin-coated metal tube 7c can be passed through before the heat-shrinkage.

  Also, the resin sleeve 3 is inserted from both ends, and has a structure in which both one-side ends 1a and 2a facing each other in the pipe are held and connected with a predetermined distance D therebetween. In actual construction, the metal sleeve 4 is crimped and the connection portion 6 is fixed by pressing the metal sleeve 4 while maintaining a predetermined distance D (approx. 1 mm or more as appropriate). .

  According to the pipe connection structure of the load heating 7, since the resin-coated metal tube 7c based on the metal tubes 1 and 2 is used, the thermal efficiency is better than that of a resin tube such as crosslinked polyethylene. Moreover, although it is a metal, anticorrosion measures are sufficient.

  If the one-side ends 1a and 2a facing each other in the resin sleeve 3 are held apart by a predetermined distance D without being abutted, electrical insulation between the connected resin-coated metal tubes 7c is secured. . If it does so, it can avoid that the resin-coated metal pipe 7c connected over the full length of the thermal radiation circuit is electrically connected in one line. This prevents the formation of long electrical circuits in the buried environment and increases the corrosion protection effect. That is, it is a measure to make it difficult for a current that causes electric corrosion to flow through the metal to be protected.

  Furthermore, since the outer periphery of the resin sleeve 3 is fitted so as to surround the metal sleeve 4 and is firmly pressed and held, the connection between the metal tubes 1 and 2 is not disconnected. Since the outer periphery of the metal sleeve 4 is further surrounded and sealed by the heat-shrinkable tube 5, the outer peripheral surface of the resin-coated metal tube 7 c is in a liquid-tight state including all the connection portions 6 and is waterproof. ing. That is, the resin-coated metal tube 7c that does not expose the metal to the embedded layer is not corroded by the acid / alkali component of the embedded layer or moisture.

  In short, since one end 1a, 2a of each of the connected resin-coated metal pipes 7c is insulated from each other at the connecting portion 6, it is possible to avoid the formation of a redundant electric circuit in the buried layer. In addition, since all of the resin-coated metal tube 7c is insulated from the buried layer and cuts off the current from the buried layer, electric corrosion can be prevented.

  Next, the present invention will be described from the viewpoint of a corrosion-resistant sleeve that connects the heat radiating pipe of the load heating 7 with the connecting portion 6. This anticorrosion sleeve is a joint that has a multilayer structure when the construction is completed, and each layer is formed by the resin sleeve 3, the metal sleeve 4, and the heat shrinkable tube 5, so that electrical insulation is provided to the concrete 7e that is an embedded layer. It is possible to firmly connect the resin-coated metal pipes 7c (metal pipes 1 and 2) so that they are held and do not leak hot water or the like.

  The resin sleeve 3 is a joint having an inner diameter that fits closely to the outer diameter of the resin-coated metal tube 7c, and has a plurality of resin-coated metal tubes so as to form a heat radiation circuit having a required length without leakage of hot water or the like. 7c (metal pipes 1 and 2) are connected together. The material of the resin sleeve 3 is preferably a crosslinked polyethylene pipe for the reasons described above.

  The diameter-reduced portions 4a and 4b of the metal sleeve 4 are reduced in diameter (crimped) with a crimping tool to prevent the connection portion 6 from coming off, and assist the function and effect as a joint so as to enhance the sealing effect. . As will be described later, the material of the metal sleeve 4 is preferably stainless steel, but other materials may be used. The diameter-reduced portions 4a and 4b have a width of about 10 mm in the longitudinal direction of the resin-coated metal tube 7c and one or more of the one-side ends 1a and 2a.

  The metal sleeve 4 whose diameter has been reduced and crimped in this way is loosely covered with the heat shrinkable tube 5 before heat shrinkage. Since this heat-shrinkable tube 5 is commercially available in various inner diameters, a long one is appropriately cut into a length. That is, a length that can seal the entire metal sleeve 4 after heat shrinkage is sufficient.

  Thus, according to the anticorrosion sleeve of the present invention, in the construction of the load heating 7 using the resin-coated metal tube 7c, it can be constructed at low cost by using an easily procured material and a general tool.

Next, the present invention will be described from the viewpoint of a connection method using the corrosion-resistant sleeve.
As a first step, before connecting the two resin-coated metal tubes 7c (metal tubes 1 and 2), a resin sleeve 3 having a predetermined length suitable as a joint is prepared.

  More specifically, a long cross-linked polyethylene pipe is prepared by cutting it into a predetermined length. That is, the resin-coated metal tube 7c (metal tubes 1 and 2) is inserted into the upper one end 1a of the upper metal tube 1 desired to be connected and the lower end 2a of the lower metal tube 2 so that they can be inserted. The resin sleeve 3 having an appropriate inner diameter commensurate with the outer diameter is cut into a predetermined length. In addition, regarding the arrangement of the metal tubes 1 and 2, the notation of “upper / lower” is for convenience to explain along the arrangement in FIG. 1, and the actual construction form is often horizontal.

  As the second step, the one end 1a, 2a of each of the two resin-coated metal tubes 7c is held in the tube of the resin sleeve 3 fitted at both ends with a predetermined distance D apart. Specifically, the upper piece side end 1a of the upper metal pipe 1 to be inserted into the resin sleeve 3 and the lower piece side end 2a of the lower tree metal pipe 2 are inserted into the resin sleeve 3 with a predetermined distance D between which they do not contact. Connect with. In addition, you may reinforce by apply | coating the seal adhesive for fluid to the part inserted in the pipe | tube of the resin sleeve 3. FIG.

  As a third step, a metal sleeve 4 having a length close to that of the resin sleeve 3 is placed on the resin sleeve 3 and is firmly pressed and held. Specifically, the metal sleeve 4 is cut to substantially the same length as the resin sleeve 3 and is fitted in contact with the outer periphery of the resin sleeve 3. Compress one part (indicated by an arrow) with a crimping tool around the entire circumference to form the reduced diameter portions 4a and 4b (two in FIG. 1 in total) having a sticking action and a sealing action, increasing the pull-out strength and strengthening the seal Plan.

  As a fourth step, the heat-shrinkable tube 5 is covered so that the metal sleeve 4 is completely covered, and then the heat-shrinkable tube 5 is heated and thermally contracted. Specifically, heat shrinkage is required to prevent corrosion caused by completely covering the exposed metal portions of the metal sleeve 4 and the resin-coated metal tube 2 and to prevent a roadbed component such as concrete from entering the resin sleeve 3. The tube 6 completely covers the connecting portion 6 and is thermally contracted to complete the electrical insulation and waterproofing measures. It should be noted that a self-bonding tape may be wound around both ends of the heat shrinkable tube 5 as reinforcement for waterproofing measures.

  Thus, the first to fourth steps are easy to construct at low cost due to a small number of man-hours. Moreover, those skilled in the art can easily cope with this within the scope of ordinary skill. Dare to explain the characteristic process, it is not a difficult process that requires skill, even if it is left to the control of the installer when holding the interval D of about several millimeters related to the second process, and it is surely For this purpose, a spacer (not shown) or the like may be interposed.

As described above, according to the pipe connection structure for load heating according to the present invention, the anticorrosion sleeve used therefor, and the connection method thereby, the following effects can be obtained.
1. Snow melting efficiency (fuel consumption) is good.
2. Long life due to anti-corrosion measures.
3. Easy to install at low cost.

  The technology of the present invention firstly reduces the fuel consumption by using a resin-coated stainless steel pipe or a metal pipe such as a steel pipe, an aluminum pipe, or a copper pipe as a pipe material to replace a crosslinked polyethylene pipe having a low thermal conductivity λ. It is to provide road heating 7 with high snow melting efficiency.

  Secondly, in order to ensure thorough anti-corrosion measures, a non-contact state was ensured so as to electrically insulate between the metal tube 1 and the metal tube 2 at the connection part between the resin-coated metal tubes 1 and 2. That is.

  Thirdly, the metal pipes 1 and 2 are connected by using a multi-layer corrosion-resistant sleeve. In this anticorrosion sleeve, the metal pipes 1 and 2 coated with the resin coatings 1j and 2j are inserted into the resin sleeve 3 at the connecting portion 6, the upper portion is reinforced with the metal sleeve 4, and the main part is used with a crimping tool. The diameter is reduced to prevent it from coming off. Further, the metal sleeve 4 is covered with a heat-shrinkable tube 5 to ensure a waterproof sealing effect.

  And even if it is embodiment which added the variation to the technique shown to the said 1st-3rd, it is considered that it is contained in this invention. The resin-coated metal tube 7c referred to in the present invention is a resin excellent in electrical insulation, chemical resistance (acid / alkali), water resistance, impact resistance, etc. on the entire outer periphery of the metal tubes 1 and 2 as a countermeasure against corrosion. And used for the heat dissipating pipe of the load heating 7. More specifically, the metal pipes 1 and 2 are subjected to a coating treatment (resin coating 1j, 2j) such as nylon or epoxy. As the resin-coated metal tube 7c, a commercially available product may be used, or a product procured by the installer by covering the metal tubes 1 and 2 with a long heat-shrinkable tube as a preliminary process may be used. Absent.

  In the present embodiment, stainless steel pipes are used as the metal pipes 1 and 2 and the metal sleeve 4 constituting the heat radiating pipe. The reason for this is that, in addition to the stability during transportation, the ease of processing due to its excellent rollability during processing, the ease of construction, etc., from the bending strength of the connecting part, etc. It also depends on the anticorrosive effect that can prevent leakage. Other metal materials may be used as long as these conditions are satisfied.

It is the longitudinal cross-sectional view which expanded the connection part of the resin-coated metal pipe. It is a top view which shows a construction state of road heating partially transparently. It is an AA line expanded sectional view in FIG.

Explanation of symbols

1, 2 (Up / Down) metal tube 1a, 2a (Up / Down) one end 1j, 2j Resin coating (Coating metal tubes 1, 2) 3 Resin sleeve 4 Metal sleeve 4a, 4b Reduced diameter part 5 Heat-shrinkable tube 6 Connection 7 Load heating 7a Crushed stone 7b Protection sheet 7c Resin-coated metal tube 7d Mesh 7e Concrete 7f Asphalt

Claims (3)

A pipe connection structure of a load heating (7) that constitutes a heat dissipation circuit that circulates a heat medium in a metal pipe that is connected to an appropriate length and embedded,
A plurality of resin-coated metal tubes (7c) having a resin coating (1j, 2j) on the outer periphery of the metal tubes (1, 2);
A resin sleeve (3) that fits one end (1a, 2a) of the connecting portion (6) of the resin-coated metal pipe (7c) from both sides to form a liquid-tight joint;
A metal sleeve (4) which is fitted on the outer periphery of the resin sleeve (3) and held by pressure bonding;
A heat shrinkable tube (5) covering the metal sleeve (4),
Load heating (7) characterized in that the one end (1a, 2a) fitted and opposed from both ends of the resin sleeve (3) is held at a predetermined distance (D). Piping connection structure. A corrosion-resistant sleeve forming a pipe connection structure of the load heating (7) according to claim 1,
A resin sleeve (3) having an inner diameter closely fitting to the outer diameter of the resin-coated metal tube (7c);
A metal sleeve (4) whose outer diameter can be reduced with a crimping tool;
A heat-shrinkable tube (5) having an inner diameter that loosely covers the outer periphery of the metal sleeve (4) that has been reduced in diameter and pressure-bonded before heat shrinkage and that can seal the entire metal sleeve (4) after heat shrinkage;
A corrosion-resistant sleeve which is a joint that forms a multilayer structure including at least the resin sleeve (3), the metal sleeve (4), and the heat-shrinkable tube (5) at the time of completion of construction. A connection method using the corrosion-resistant sleeve according to claim 2,
A first step of preparing the resin sleeve (3) having a predetermined length before connecting the two resin-coated metal tubes (7c);
A second step of connecting the one side ends (1a, 2a) at a predetermined distance (D) in a pipe of the resin sleeve (3) in which the one side ends (1a, 2a) are fitted at both ends;
A third step of pressing and holding the metal sleeve (4) having a length close to the resin sleeve (3) over the resin sleeve (3);
And a fourth step of heat-shrinking the heat-shrinkable tube (5) after covering the heat-shrinkable tube (5) so that the metal sleeve (4) is completely covered. Connection method using a corrosion resistant sleeve.

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