JP2009036264A - Pipe connecting structure of liquid supplying place - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need of leakage inspection by thermal welding a resin pipe, a metal pipe, and a connecting structure. <P>SOLUTION: The pipe connecting structure 100A is a structure uniting an end portion of the resin pipe 110 and an end portion of the metal pipe 130 by thermal welding through a resin joint 120. After inserting the resin pipe 110 and the metal pipe 130 into the resin joint 120, voltage is applied in electrodes 142, 144. Therefore, an inner wall of the resin joint 120 fitted with the resin pipe 110 and the metal pipe 130 is heated to be high temperature. The inner wall of the resin joint 120 is melted when reaching the melting temperature of resin material, and welded to an outer periphery of an end portion 110a of the resin pipe 110, an outer periphery of an end portion 134a of a resin layer 134 formed on an inner side of the metal pipe 130, and an outer periphery provided with a resin layer 135 of an end portion 132a of a steel pipe 132 formed on an outer side of the metal pipe 130. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe connection structure for a liquid supply station, and more particularly to a pipe connection structure for a liquid supply station configured to connect an underground tank and a ground pipe line via a resin pipe.

  For example, in a liquid supply station, an underground tank for supplying liquid for storing an oil liquid (fuel) to be supplied is buried, and a measuring tank, an injection pipe, a communication pipe installed on the ground for the supplied liquid and the ground. The trachea is connected to the trachea via a pipe. In addition, there are cases where waste oil underground tanks that store used oil are buried in the liquid supply station. Similarly, there are waste oil underground tanks, waste oil recovery ports and waste oil discharge ports arranged on the ground. Connected via piping. Conventionally, these pipes are made of steel pipes, and bolts are inserted between flanges provided at the ends of the pipes, and nuts are screwed into the bolts to fasten the flanges. The connection location of each pipe buried in the ground is liquid-tightly sealed by a seal member, and the seal member between the flanges is compressed by tightening bolts and nuts to prevent liquid leakage.

  In this way, in the case of a flange connection structure, it is necessary to provide a manhole for inspection so that the state of the seal member (presence or absence of leakage) can be checked from the ground, and periodically confirm that there is no liquid leakage between the flanges. Is required. In recent years, the use of resin piping has been promoted as a countermeasure against corrosion by steel pipes.

By the way, the resin pipe can integrally weld (fuse) the ends of the resin pipe by melting and joining the resin materials by heat (for example, see Patent Document 1). According to this joining method by heat welding, it is possible to make a connection without using the flange, and it is not necessary to inspect for liquid leakage between the flanges. Can be reduced.
JP 2006-205501 A

  In the pipe connection structure of the liquid supply station, it is allowed to use a resin pipe for a pipe buried at a depth greater than or equal to a predetermined depth in the basement. The pipes exposed to fire are determined by the Fire Service Act to use metal pipes such as steel pipes that are not easily affected by heat due to problems of resin combustion and deterioration due to fire.

For this reason, since all piping of a liquid supply station cannot be made into resin piping, there existed a problem that it was difficult to switch the connection structure of each piping from a flange connection to a heat welding connection.
Moreover, as a connection method between the resin pipe and the steel pipe, there is a pipe connection structure that does not use a flange. In this method, a screwed metal part for connecting a steel pipe is attached to the resin pipe, or the end of the resin pipe and the outer periphery of the steel pipe are fastened and fixed. Thus, in the method of connecting between the resin pipe and the steel pipe, since the connecting portion is regarded as a joint, a joint inspection manhole or pit for inspecting the joint portion for leakage must be provided.

  Therefore, in view of the above circumstances, an object of the present invention is to provide a pipe connection structure for a liquid supply station that solves the above-described problems.

  In order to solve the above problems, the present invention has the following means.

  The present invention includes an underground tank buried underground in a liquid supply station, a resin pipe having one end connected to the underground tank and the other end extending in the horizontal direction, and a resin layer on at least one of an inner periphery and an outer periphery. One end of the metal pipe formed integrally and having one end connected to the resin pipe through the resin layer and the other end extending to the ground, the other end of the resin pipe and the resin layer A resin joint fitted to the outer periphery of the resin, and a heating wire provided on the resin joint, and by energizing the heating wire, the resin pipe, the resin layer of the metal tube, and the resin joint The above-described problem is solved by melting and fixing the fitting portion.

  The present invention provides an annular flange at one end of the metal pipe and the other end of the resin pipe, and fastens between the pair of annular flanges by a fastening member. The resin pipe, the resin layer of the metal pipe, and the resin joint The above-mentioned problems are solved by melting and fixing the fitting portion.

  The present invention provides a female screw at one end of the metal tube or the other end of the resin pipe, and provides a male screw screwed to the female screw at the other end of the metal tube or the other end of the resin pipe, The above problem is solved by melting and fixing the resin pipe, the resin layer of the metal pipe, and the fitting portion of the resin joint.

  According to the present invention, one end of a metal tube in which a resin layer is integrally formed on at least one of the inner periphery and the outer periphery is connected to the resin pipe via the resin layer, and the other end of the metal tube is on the ground. Because it is provided to extend, the resin pipe buried in the ground and one end of the metal pipe are joined by heat welding connection, and the other end of the metal pipe not formed with the resin layer is exposed to the ground. This makes it possible to simplify the maintenance work by eliminating the need to check the connecting portion between the resin pipe and the metal pipe.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing an underground tank facility of a liquid supply station to which one embodiment of a pipe connection structure of a liquid supply station according to the present invention is applied. As shown in FIG. 1, for example, an underground tank facility 10 installed in a liquid supply station includes an underground tank 12 for storing oil liquid, a weighing machine 14 for supplying liquid, and an opening on the ground surface above the underground tank 12. A manhole (arranged in three places in this embodiment) 16, an unloading pipe 18 to which an unloading hose 28 is connected, a liquid injection pipe 24 communicated with the lower end of the unloading pipe 18, an aeration pipe 26, an underground tank 12, A horizontal pulling pipe 70 that communicates with the ventilation pipe 26 is provided.

  And the other end of the liquid absorption pipe 22 and the liquid injection pipe 24 is connected to each pipe joint 60 provided at the top of the underground tank 12 corresponding to the oil type of the oil liquid passing therethrough.

  The vent pipe 26 has a vent hole 26a at the upper end standing on the ground, and the lower end communicates with one end of a horizontal pull pipe 70 extending in a substantially horizontal direction between the ground surface (reinforced concrete 30) and the top of the underground tank 12. Has been. The other end of the horizontal pipe 70 connected to the ventilation pipe 26 is connected to each pipe joint 60 provided at the top of the underground tank 12.

  The laterally extending portions extending laterally in the ground, such as the liquid absorbing pipe 22, the liquid injection pipe 24, and the horizontal pulling pipe 70, are made of resin pipes. In fact, the underground tank 12 and the weighing machine 14, the unloading pipe 18, and the ventilation pipe 26 are considerably separated according to the site area of the liquid supply station (for example, about 10m to 20m). The pipe 22, the liquid injection pipe 24, and the horizontal pulling pipe 70 are extended accordingly. Therefore, a plurality of resin pipes are connected to the liquid absorption pipe 22, the liquid injection pipe 24, and the horizontal drawing pipe 70 by heat welding connection. In addition, since the connection structure of resin piping is a well-known thing, the description is abbreviate | omitted here.

  The unloading pipe 18 and the ventilation pipe 26 installed on the ground are made of metal pipes such as steel pipes, and the liquid injection pipe 24 and the horizontal pipe 70 buried in the ground are resins made of reinforced plastic such as polyethylene. It consists of piping. The metal pipe and the resin pipe are connected by a pipe connection structure 100 joined by heat welding. Details of the pipe connection structure 100 will be described with reference to FIG.

  The liquid absorption pipe 22, the liquid injection pipe 24 and the horizontal pipe 70 are inclined at a predetermined angle from the horizontal so that the connecting portion with the underground tank 12 is lowered so that the oil liquid in the pipe falls into the underground tank 12. Is provided. In addition, the underground tank 12 is provided with an inspection port, a liquid level gauge (both not shown) and the like in addition to the above-described pipes, but the description thereof is omitted.

  The driver of the tank truck 20 arriving at the liquid supply station confirms the liquid type and the remaining amount in the underground tank 12 and loads and discharges the hatch bottom valve (not shown) loaded with the corresponding liquid type. An unloading hose 28 communicates with the pipe 18. Then, after the driver confirms the liquid type, the bottom valve is opened, so that the oil liquid loaded in the hatch is taken from the unloading hose 28 through the liquid injection pipe 24 using the height difference and the underground tank 12. Unloaded.

In the liquid supply station, the ground surface is formed of reinforced concrete 30 having a thickness of 30 cm, and a soil layer 32 having a thickness of 30 cm is formed below the reinforced concrete 30. Furthermore, the underground tank 12 is embedded in a soil layer 34 formed below the earth and sand layer 32, and is placed on a concrete foundation layer 36 laid in the ground.
Moreover, since the liquid absorption piping 22, the injection piping 24, and the horizontal piping 70 consist of resin piping, they were formed under the earth and sand layer 32 so that it might become a depth more than predetermined depth (for example, about 1 m). It is buried in the soil layer 34. As a result, the liquid absorption pipe 22, the liquid injection pipe 24, and the horizontal pipe 70 are prevented from being damaged by a load from a large vehicle such as an earthquake or a tank truck 20 and are not heated even if a fire occurs on the ground. Buried in

  The manhole 16 is provided at a location where the liquid suction pipe 22, the liquid injection pipe 24, and the horizontal pipe 70 are connected to the upper part of the underground tank 12, and each pipe is individually connected to the internal space of the manhole 16. A pipe joint 60 is accommodated. A liquid absorption insertion pipe 62 into which the underground tank 12 is inserted is connected to the lower end of the pipe joint 60 constituting the liquid absorption system to which the liquid absorption pipe 22 is connected. In addition, a liquid injection pipe 64 into which the underground tank 12 is inserted is connected to the lower end of the pipe joint 60 that constitutes the liquid injection system to which the liquid injection pipe 24 is connected.

  FIG. 2 is a perspective view showing a schematic configuration of the underground tank facility 10 of the liquid supply station. As shown in FIG. 2, the weighing machine 14 is provided with liquid supply nozzles 15 a to 15 c for supplying regular gasoline, high-octane gasoline, and light oil. Moreover, one end of regular gasoline, high-octane gasoline, and light oil absorption pipes 22a to 22c corresponding to the liquid types supplied by the liquid supply nozzles 15a to 15c is connected to the bottom of the weighing machine 14. For example, the inside of the underground tank 12 is divided into two chambers by a partition wall, and stores high-octane gasoline and light oil. Regular gasoline is stored in another single underground tank (not shown).

  The other ends of the liquid suction pipes 22 b and 22 c and the liquid injection pipes 24 b and 24 c are connected to pipe joints 60 disposed in the manhole 16 protruding from the top of the underground tank 12. Moreover, the other end of the liquid absorption pipe 22a and the liquid injection pipe 24a is extended to another underground tank. Further, each pipe joint 60 is connected with a horizontal pipe 70 of the vent pipe 26 and liquid injection pipes 24a to 24c for unloading. The liquid injection pipes 24 a to 24 c are arranged for each liquid type of regular gasoline, high-octane gasoline, and light oil, and one end of the liquid injection pipe 24 a to 24 c is an unloading pipe of the liquid filling port storage unit 80 provided near the unloading position of the tank truck 20. 18 and the other end is connected to a pipe joint 60 disposed in a manhole 16 provided for each liquid type.

  Here, the pipe connection structure 100 will be described.

  FIG. 3A is an enlarged longitudinal sectional view showing the pipe connection structure 100A. As shown in FIG. 3A, the pipe connection structure 100 </ b> A is a structure in which the end of the resin pipe 110 and the end of the metal pipe 130 are joined by thermal welding via the resin joint 120.

  The end of the resin pipe 110 is inserted into one end opening 122 of the resin joint 120 formed in a cylindrical shape. A metal tube 130 is inserted into the other end opening 124 of the resin joint 120. In the metal tube 130, a cylindrical resin layer 134 is formed in close contact with the inner periphery of the steel tube 132 without any gap. Further, the thickness (radial dimension) of the resin layer 134 is formed to be substantially the same as the thickness (radial dimension) of the steel pipe 132.

  In the metal tube 130, the end portion 134 a of the resin layer 134 protrudes in the axial direction (horizontal direction) from the end portion 132 a of the steel tube 132, and the resin layer 135 is also formed on the outer periphery of the steel tube 132. The resin layer 135 is thinner than the resin layer 134, and it is only necessary to secure a melting allowance for ensuring the sealing performance of the joint portion with the resin joint 120. Further, the outer periphery of the metal pipe 130 is fitted to the inner wall of the small diameter portion 126 formed inside the other end opening 124 of the resin joint 120 and the outer periphery provided with the resin layer 135 of the end portion 132a of the steel pipe 132. Is fitted to the inner wall of the other end opening 124.

  The resin joint 120, the resin layer 134, and the resin layer 135 are molded from a reinforced plastic such as polyethylene similarly to the resin pipe 110. A heating wire 140 is insert-molded on the inner peripheral side of the resin joint 120. The heating wire 140 is a heating means for heat welding, and is formed in a spiral shape so as to be close to the inner wall according to the inner wall shape of the resin joint 120, and is an electrode whose both ends are exposed to the outer periphery of the resin joint 120. 142 and 144.

  The resin pipe 110 has an outer diameter that is slightly larger than the inner diameter of the one end opening 122. The outer diameter of the end portion 110 a of the resin pipe 110 is narrowed to a size that is slightly smaller than the inner diameter of the one end opening 122. Therefore, when the end portion 110a of the resin pipe 110 is inserted into the one end opening 122 of the resin joint 120, further insertion of the resin pipe 110 is prevented.

  Further, the outer diameter of the end portion 134 a of the resin layer 134 is formed to be slightly smaller than the inner diameter of the small diameter portion 126, and the outer diameter of the end portion 132 a of the steel pipe 132 provided with the resin layer 135 is equal to that of the other end opening 124. The diameter is slightly smaller than the inner diameter. The metal tube 130 is prevented from being inserted further by the end portion 132a of the steel tube 132 formed on the outer periphery of the resin layer 134 being in contact with the step portion between the small diameter portion 126 and the other end opening 124. .

  A gap S is interposed between the resin pipe 110 inserted into the resin joint 120 and the metal pipe 130, and even if thermal expansion occurs, the expansion amount corresponding to the gap S is absorbed to maintain a non-contact state. Can do.

  As described above, after the resin pipe 110 and the metal pipe 130 are inserted into the resin joint 120, a voltage is applied to the electrodes 142 and 144. Thereby, the inner wall of the resin joint 120 in which the resin pipe 110 and the metal pipe 130 are fitted is heated to a high temperature. The inner wall of the resin joint 120 is melted when the melting temperature of the resin material is reached, and the outer periphery of the end portion 110a of the resin layer 134 formed on the outer periphery of the end portion 110a of the resin pipe 110 and the inner side of the metal tube 130. The outer periphery of the steel pipe 132 formed on the outer side of the metal pipe 130 is welded to the outer periphery provided with the resin layer 135.

  The inner wall of the one end opening 122 of the resin joint 120 is fused and integrally joined to the end portion of the resin pipe 110 by the heating of the heating wire 140. Further, the inner wall of the other end opening 124 of the resin joint 120 is fused and integrally bonded to the outer periphery of the metal pipe 130 on which the resin layer 135 of the end 132a of the steel pipe 132 is provided by heating the heating wire 140. Is done. Further, the inner wall of the small-diameter portion 126 of the resin joint 120 is fused and integrally joined to the outer periphery of the end portion 134 a of the resin layer 134 of the metal tube 130 by the heating of the heating wire 140.

  Thereby, the end of the resin pipe 110 and the end of the metal pipe 130 are coupled via the resin joint 120, and the flow path 112 formed inside the resin pipe 110 and the inside of the metal pipe 130 are connected. The formed flow path 136 is communicated.

  Therefore, according to the pipe connection structure 100A, the end portion of the resin pipe 110 and the end portion of the metal pipe 130 are joined by heat welding through the resin joint 120, so that the conventional flange connection structure is used. There is no need to conduct a leak inspection, and there is no need to provide an inspection manhole for the leak inspection.

  FIG. 3B is an enlarged longitudinal sectional view showing the pipe connection structure 100Aa. In FIG. 3B, the same parts as those in FIG. 3A are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 3B, the pipe connection structure 100 </ b> Aa is formed so that the resin layer 134 is in close contact with the inner wall of the end opening 138 of the steel pipe 132. The resin layer 134 is thermally welded by fitting a portion protruding from the end opening 138 of the steel pipe 132 into the small diameter portion 124 of the resin joint 120. As described above, the resin layer 134 may be formed only on the end portion of the metal tube 130. Also in this example, the resin layer 135 is provided on the outer periphery of the expanded portion of the steel pipe 132 as in FIG. 3A.

  FIG. 4A is an enlarged longitudinal sectional view showing the pipe connection structure 100B. In FIG. 4A, the same parts as those in FIG. As shown in FIG. 4A, the pipe connection structure 100 </ b> B is a structure in which the end of the resin pipe 110 and the end of the metal pipe 230 are joined by thermal welding via a resin joint 220.

  The end of the resin pipe 110 is inserted into the one end opening 222 of the resin joint 220 formed in a cylindrical shape. A metal tube 230 is inserted into the other end opening 224 of the resin joint 220. In the metal tube 230, a cylindrical resin layer 234 is formed in close contact with the outer periphery over the entire length of the steel tube 232 without a gap. Further, the thickness (radial dimension) of the resin layer 234 is formed to be substantially the same as the thickness (radial dimension) of the steel pipe 232.

  The metal pipe 230 is formed such that the resin layer 234 covers the outer periphery of the steel pipe 232, and the end portion 234 a of the resin layer 234 covers the end portion of the steel pipe 232. The inner wall of the end opening 224 is fitted.

  The resin joint 220 and the resin layer 234 are formed of a reinforced plastic such as polyethylene similarly to the resin pipe 110. A heating wire 140 is insert-molded on the inner peripheral side of the resin joint 220.

  Further, the outer diameter of the end portion 234 a of the resin layer 234 is slightly smaller than the inner diameter of the other end opening 224 of the resin joint 220. Since the outer diameter of the resin layer 234 is slightly larger than the inner diameter of the other end opening 224, the metal tube 230 is prevented from being inserted further.

  A gap S is interposed between the resin pipe 110 inserted into the resin joint 220 and the metal pipe 230. Even if thermal expansion occurs, the expansion amount corresponding to the gap S is absorbed to maintain a non-contact state. Can do.

  As described above, after the resin pipe 110 and the metal pipe 230 are inserted into the resin joint 220, a voltage is applied to the electrodes 142 and 144. Thereby, the inner wall of the resin joint 220 into which the resin pipe 110 and the metal pipe 230 are fitted is heated to a high temperature. The inner wall of the resin joint 220 is melted when the melting temperature of the resin material is reached, and the outer periphery of the end portion 234a of the resin layer 234 formed on the outer periphery of the end portion 110a of the resin pipe 110 and the outer side of the metal tube 230. To be welded.

  The inner wall of the one end opening 222 of the resin joint 220 is fused and integrally joined to the end of the resin pipe 210 by the heating of the heating wire 140. Further, the inner wall of the other end opening 224 of the resin joint 220 is fused and integrally joined to the outer periphery of the end portion 234 a of the resin layer 234 of the metal tube 230 by the heating of the heating wire 140.

  As a result, the end of the resin pipe 110 and the end of the metal pipe 230 are coupled via the resin joint 220, and the flow path 112 formed inside the resin pipe 110 and the inside of the metal pipe 230 are connected. The formed flow path 236 is communicated.

  Therefore, according to the pipe connection structure 100B, the end portion of the resin pipe 110 and the end portion of the metal pipe 230 are joined by heat welding via the resin joint 220, so that the conventional flange connection structure is used. There is no need to conduct a leak inspection, and there is no need to provide an inspection manhole for the leak inspection.

  FIG. 4B is an enlarged longitudinal sectional view showing the pipe connection structure 100Ba. In FIG. 4B, the same parts as those in FIG. As shown in FIG. 4B, the pipe connection structure 100Ba is formed so that the resin layer 234 is in close contact with the outer periphery of the end of the steel pipe 232. The resin layer 234 is fitted into the other end opening 224 of the resin joint 220 and thermally welded. As described above, the resin layer 234 may be formed in a portion that fits into the other end opening 224 of the resin joint 220.

  FIG. 5A is an enlarged longitudinal sectional view showing the pipe connection structure 100C. As shown in FIG. 5A, the pipe connection structure 100 </ b> C is a structure in which the end of the resin pipe 310 and the end of the metal pipe 330 are joined by heat welding via a resin joint 320.

The resin pipe 310 has a flange 312 formed in a disc shape on the outer periphery of the end. A female screw 314 for screwing a bolt is provided on the end surface of the flange 312.
In the metal tube 330, the resin layer 334 is closely formed on the outer periphery of the steel tube 332 without any gap. Further, the thickness (radial dimension) of the resin layer 334 is formed to be substantially the same as the thickness (radial dimension) of the steel pipe 332.

The steel pipe 332 of the metal pipe 330 has a flange 336 at the end. The resin layer 334 is formed so as to cover the outer periphery of the steel pipe 332 excluding the flange 336. The flange 336 is provided with a bolt insertion hole 338 at a position facing the female screw 314.
The flange 336 of the metal pipe 330 is opposed to the flange 312 of the resin pipe 310, and the bolt 340 is screwed into the female screw 314 from the bolt insertion hole 338 to tighten the head of the bolt 340. As a result, the packing 350 is interposed between the flange 312 of the resin pipe 310 and the flange 336 of the metal pipe 330 and is fastened by the bolt 340. The packing 350 provides a liquid-tight seal between the flanges 312 and 336, and prevents the flange 312 of the resin pipe 310 from coming into contact with the flange 336 of the metal pipe 330 and deforming.

  The resin joint 320 includes one end opening 322 in which the outer periphery of the flange 312 of the resin pipe 310 is fitted, the other end opening 324 in which the outer periphery of the resin layer 234 of the metal pipe 330 is fitted, and one end opening 322 having a large diameter. And a step portion 326 that connects the other end opening 324 having a small diameter. Further, the step portion 326 forms a space 360 for accommodating the head portion of the bolt 340 between the step portion 326 and the flange 336.

Further, in the resin joint 320, the heating wire 140 is insert-molded in the vicinity of the inner periphery of the one end opening 322 and the other end opening 324 excluding the step portion 326. Electrodes 142 and 144 connected to the heating wire 140 are provided on the outer peripheral side of the one end opening 322 and the outer peripheral side of the other end opening 324, respectively.
After the resin pipe 310 and the metal pipe 330 are inserted into the resin joint 320, the flange 312 of the resin pipe 310 and the flange 336 of the metal pipe 330 are fastened by tightening the bolt 340, and then the one end opening 322 and the other end A voltage is applied to the electrodes 142 and 144 arranged on the outer peripheral side of the opening 324. Thereby, the inner wall of the resin joint 320 into which the resin pipe 310 and the metal pipe 330 are fitted is heated to a high temperature. The inner wall of the resin joint 320 is melted at the time when the melting temperature of the resin material is reached and is welded to the outer periphery of the flange 312 of the resin pipe 310 and the outer periphery of the resin layer 334 formed on the outer side of the metal tube 330.

  The inner wall of the one end opening 322 of the resin joint 320 is fused and integrally joined to the flange 312 of the resin pipe 310 by heating the heating wire 140. Further, the inner wall of the other end opening 324 of the resin joint 320 is fused and integrally joined to the outer periphery of the resin layer 334 of the metal tube 330 by the heating of the heating wire 140.

  As a result, the resin pipe 310 and the metal pipe 330 are coupled via the resin joint 320, and the flow path 316 formed inside the resin pipe 310 and the flow path 339 formed inside the steel pipe 332. And communicated with each other.

  Therefore, according to the pipe connection structure 100C, the flange 312 of the resin pipe 310 and the resin layer 334 of the metal pipe 330 are joined by thermal welding via the resin joint 320, so that the conventional flange connection structure is used. It is not necessary to perform a leak inspection on the door, and it is not necessary to provide an inspection manhole for the leak inspection.

  FIG. 5B is an enlarged longitudinal sectional view showing the pipe connection structure 100Ca. In FIG. 5B, the same parts as those in FIG. As shown in FIG. 5B, the pipe connection structure 100Ca is formed so that the resin layer 334 is in close contact with the outer periphery of the end of the steel pipe 332. The resin layer 334 is fitted into the other end opening 324 of the resin joint 320 and thermally welded. As described above, the resin layer 334 may be formed in a portion that fits into the other end opening 324 of the resin joint 320.

  FIG. 6A is an enlarged longitudinal sectional view showing the pipe connection structure 100D. As shown in FIG. 6A, the pipe connection structure 100 </ b> D is a structure in which the end of the resin pipe 410 and the end of the metal pipe 430 are joined by heat welding via a resin joint 420.

The resin pipe 410 has a large-diameter portion 412 that is thick at the end. A metal nut 414 is insert-molded in the end surface recess 413 of the large diameter portion 412.
In the metal tube 430, the resin layer 434 is formed in close contact with the outer periphery of the steel tube 432 without a gap. Further, the outer periphery of the end portion of the steel pipe 432 is not covered with the resin layer 434 and is formed with a male screw 436 to be screwed into the nut 414.

  The male pipe 430 is screwed into the nut 414 of the resin pipe 410 and tightened. As a result, the resin pipe 410 and the metal pipe 430 are fastened with screws.

  The resin joint 420 has one end opening 422 into which the outer periphery of the large-diameter portion 412 of the resin pipe 410 is fitted, the other end opening 424 into which the outer periphery of the resin layer 434 of the metal pipe 430 is fitted, and one end opening with a large diameter. 422 and a step 426 connecting the other end opening 424 having a small diameter. Further, the stepped portion 426 forms a gap S between the large diameter portion 412.

Further, in the resin joint 420, the heating wire 140 is insert-molded in the vicinity of the inner periphery of the one end opening 422 and the other end opening 424 excluding the step portion 426. Electrodes 142 and 144 connected to the heating wire 140 are provided on the outer peripheral side of the one end opening 422 and the outer peripheral side of the other end opening 424, respectively.
After the male screw 436 of the metal pipe 430 is screwed into the nut 414 of the resin pipe 410 and fastened, the voltage is applied to the electrodes 142 and 144 arranged on the outer peripheral side of the one end opening 422 and the other end opening 424. To do. Thereby, the inner wall of the resin joint 420 into which the resin pipe 410 and the metal pipe 430 are fitted is heated to a high temperature. Then, the inner wall of the resin joint 420 is melted when the melting temperature of the resin material is reached, and is welded to the outer periphery of the large diameter portion 412 of the resin pipe 410 and the outer periphery of the resin layer 434 formed outside the metal tube 430. The

  The inner wall of the one end opening 422 of the resin joint 420 is fused and integrally joined to the large diameter portion 412 of the resin pipe 410 by the heating of the heating wire 140. Further, the inner wall of the other end opening 424 of the resin joint 420 is fused and integrally joined to the outer periphery of the resin layer 434 of the metal tube 430 by the heating of the heating wire 140.

  Thereby, the resin pipe 410 and the metal pipe 430 are coupled via the resin joint 420, and the flow path 416 formed inside the resin pipe 410 and the flow path 439 formed inside the steel pipe 432. And communicated with each other.

  Therefore, according to the pipe connection structure 100D, the large-diameter portion 412 of the resin pipe 410 and the resin layer 434 of the metal pipe 430 are joined by heat welding via the resin joint 420, so that the conventional flange connection structure Thus, it is not necessary to perform a leak inspection as in the above, and it is not necessary to provide an inspection manhole for the leak inspection.

  FIG. 6B is an enlarged longitudinal sectional view showing the pipe connection structure 100Da. 6B, the same parts as those in FIG. 6A are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 6B, the pipe connection structure 100 </ b> Da is formed so that the resin layer 434 is in close contact with the outer periphery of the end of the steel pipe 432. The resin layer 434 is fitted into the other end opening 424 of the resin joint 420 and thermally welded. In this manner, the resin layer 434 may be formed in a portion that fits into the other end opening 424 of the resin joint 420.

  FIG. 7 is a longitudinal sectional view showing a construction example 1 on the other end side exposed to the ground of the metal pipe. In FIG. 7, the metal tube 130 will be described, but the other metal tubes 230, 330, and 430 are the same, and thus the description thereof is omitted. As shown in FIG. 7, the metal tube 130 is embedded in the ground in a state inclined at a predetermined angle with respect to the horizontal direction. The other end 500 of the metal tube 130 is embedded in a concrete layer 510 protruding from the upper surface of the reinforced concrete 30, and a fastening portion having a male screw 520 protrudes from the concrete layer 510.

  Thus, by covering the other end 500 of the metal tube 130 with the concrete layer 510, the other end 500 can be protected from fire, vehicles, and the like. Therefore, when the fire occurs, the other end 500 of the metal tube 130 is prevented from being directly heated, and the heat is not easily conducted to the steel tube 132. Therefore, the resin layer 134 provided on the metal tube 130 is prevented from being melted and deformed by heat conduction due to a fire.

  FIG. 8 is an enlarged longitudinal sectional view showing the other end 500 of the metal tube 130. As shown in FIG. 8, a joint 530 having a female screw 532 that is screwed into a male screw 520 provided on the outer periphery of the other end 500 of the metal tube 130 is screwed. Steel pipes such as the unloading pipe 18 and the ventilation pipe 26 are screwed and connected above the joint 530. Accordingly, the metal pipe 130 is covered with the concrete layer 510 at a lower portion than the male screw 520 to which the joint 530 is connected.

  FIG. 9 is a longitudinal sectional view showing a construction example 2 on the other end side exposed to the ground of the metal pipe. Although the metal tube 130 will be described with reference to FIG. 9, the other metal tubes 230, 330, and 430 are the same, and thus the description thereof is omitted. As shown in FIG. 9, the other end 500 of the metal tube 130 extends in the horizontal direction, and the tip end side thereof is formed in an arc shape curved in the vertical direction, and protrudes upward from the upper surface of the reinforced concrete 30. A heat pipe fitting 600 is attached to the outer periphery of the other end 500 protruding from the upper surface of the reinforced concrete 30. The heat pipe fixture 600 is formed of a metal material having high thermal conductivity such as aluminum, and is coupled to the upper end of the heat pipe 700 embedded vertically in the ground so as to conduct heat.

  The heat pipe 700 is a closed-loop heat conduction member that uses latent heat of liquid evaporation and condensation, and has a configuration capable of conducting a large amount of heat with a small temperature difference. Therefore, when the other end 500 of the metal tube 130 is heated by a fire, the heat of the metal tube 130 can be efficiently released to the ground by the heat pipe 700. Therefore, the resin layer 134 provided on the metal tube 130 is prevented from being deformed by a fire due to heat transfer by the heat pipe 700.

  In the above embodiment, the pipe connection structure of the metal pipe connected to the underground tank for supplying liquid has been described as an example. However, the present invention is not limited to this, and other underground tanks installed in the supplying station (for example, waste oil) Of course, the present invention can be applied to a pipe connection structure of a metal pipe connected to a storage tank or the like.

It is a block diagram which shows the underground tank installation of the liquid supply station where one Example of the pipe connection structure of the liquid supply station by this invention is applied. It is a perspective view which shows schematic structure of the underground tank equipment 10 of a liquid supply station. It is a longitudinal cross-sectional view which expands and shows the piping connection structure 100A. It is a longitudinal cross-sectional view which expands and shows piping connection structure 100Aa. It is a longitudinal cross-sectional view which expands and shows the piping connection structure 100B. It is a longitudinal cross-sectional view which expands and shows piping connection structure 100Ba. It is a longitudinal cross-sectional view which expands and shows the piping connection structure 100C. It is a longitudinal cross-sectional view which expands and shows the piping connection structure 100Ca. It is a longitudinal cross-sectional view which expands and shows the piping connection structure 100D. It is a longitudinal cross-sectional view which expands and shows piping connection structure 100Da. It is a longitudinal cross-sectional view which shows the construction example 1 of the other end side exposed to the ground of a metal pipe. It is a longitudinal cross-sectional view which expands and shows the other end 500 of the metal pipe. It is a longitudinal cross-sectional view which shows the construction example 2 of the other end side exposed to the ground of a metal pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Underground tank equipment 12 Underground tank 14 Weighing machine 16 Manhole 18 Unloading piping 20 Tank truck 22, 22a-22c Absorption piping 24, 24a-24c Injection piping 26 Aeration piping 28 Unloading hose 30 Reinforced concrete 32 Sediment layer 34 Soil layer 60 Piping joint 70 Horizontal piping 100, 100A, 100Aa, 100B, 100Ba, 100C, 100Ca, 100D, 100Da Pipe connection structure 110, 310, 410 Resin piping 120, 220, 320, 420 Resin joint 122, 222 One end opening 124, 224 Other end opening 126 Small diameter portion 130, 230, 330, 430 Metal tube 132, 232, 332, 432 Steel tube 134, 135, 234, 334, 434 Resin layer 140 Heating wire 142, 144 Electrode 312, 336 Flange 340 Bolt 41 4 Nut 436 Male thread 500 Other end 510 Concrete layer 520 Male thread 530 Joint 600 Heat pipe fitting 700 Heat pipe

Claims (3)

An underground tank buried underground in the water supply station;
A resin pipe having one end connected to the underground tank and the other end extending in a horizontal direction;
A resin layer is integrally formed on at least one of the inner periphery and the outer periphery, one end is connected to the resin pipe through the resin layer, and the other end extends to the ground, and
A resin joint fitted to the outer periphery of one end of the metal pipe provided with the other end of the resin pipe and the resin layer;
A heating wire provided in the resin joint;
With
A pipe connection structure for a liquid supply station, wherein the resin pipe, the resin layer of the metal pipe, and the fitting portion of the resin joint are melted and fixed by energizing the heating wire.   An annular flange is provided at one end of the metal pipe and the other end of the resin pipe, the pair of annular flanges are fastened by a fastening member, and the resin pipe, the resin layer of the metal pipe, and the fitting portion of the resin joint The pipe connection structure for a liquid supply station according to claim 1, wherein the pipe is melt-fixed.   One end of the metal tube or the other end of the resin pipe is provided with a female screw, the other end of the metal pipe or the other end of the resin pipe is provided with a male screw that is screwed to the female screw, the resin pipe, The pipe connection structure for a liquid supply station according to claim 1, wherein a resin layer of the metal pipe and a fitting portion of the resin joint are melted and fixed.

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