JP6925949B2 - Piping protection structure - Google Patents

Description

The present invention relates to a pipe protection structure that protects these pipes from sandblasting in an intersection region where two or more pipes intersect in the ground, and in particular, a ground that collects heat in the ground or dissipates heat into the ground. The present invention relates to a pipe protection structure preferably applied to underground pipes of a geothermal heat pump system.

Many pipes are buried underground to support people's lives. As such a pipe buried in the ground, there is a geothermal heat pump system. The pipe protection structure according to the present invention is not limited to this geothermal heat pump system, but is suitably applied to this geothermal heat pump system. The geothermal heat pump system will be described.

This underground heat heat pump system absorbs heat for heating from the ground by burying a heat exchanger consisting of a U-shaped tube in the ground and circulating a heat medium in the heat exchanger to exchange heat. Or to release excess heat in a room equipped with a heat pump into the ground. The heat exchanger in this underground heat heat pump system is also called a heat collection / heat dissipation pipe, and these heat collection pipes (tubes that circulate the heat medium from the lower end to the ground) and two heat dissipation pipes (tubes that circulate the heat medium to the lower end). The lower ends of the tubes are connected to each other via a joint member. In such a configuration, when low-temperature exhaust heat (during heating) is sent from the sending side tube, it absorbs the heat in the ground, and heat circulation occurs that is guided from the returning side tube to the heat pump via the U-shaped pipe joint. .. On the contrary, when high-temperature exhaust heat (during cooling) is sent from the sending side tube, heat is dissipated into the ground, and heat circulation is guided from the returning side tube to the heat pump via the U-shaped pipe joint. Occurs.

Patent No. 5996238 (Patent Document 1) discloses a piping system capable of improving the construction efficiency required for pipe installation by reducing the number of joints and joint connection points in such a ground source heat pump system. ..
In the piping system disclosed in Patent Document 1, the upper ends of two tubes embedded in the ground are connected to each other with the axial direction oriented in the vertical direction, and a first port is provided at one end. A U-shaped pipe joint having a through hole that is bifurcated from one mouth and extends in a substantially U shape, and a U-shaped pipe joint that is arranged substantially parallel to the branch ends located at both ends of the through hole, and each of them is arranged. A pipe joint including a pair of branch pipes having a second port communicating with the upper end of the tube and the pair of branch pipes arranged at intervals is used. The piping system includes a ground pipe for the sending side that feeds the fluid toward the tube and a ground pipe for the return side that feeds the fluid from the tube, and the feeding side tube with the upstream side facing the ground side. And a return side tube arranged with the downstream side facing the ground side, and the feed side tube and the lower end of the return side tube are connected to each other, and the upper end of the feed side tube of the two sets of the tubes is connected. The upper ends of the return pipes and the upper ends of the return pipes are connected to the second port of the pipe joint via a socket, and the first port of the pipe joint connected to the upper end of the feed side tube is the ground pipe for the feed side. The first port of the pipe joint connected to the upper end of the return side tube is connected to the return side ground pipe, and the tube is vertically drilled in the ground in a boring hole. The above-ground pipe for the sending side and the above-ground pipe for the return side are arranged substantially in parallel with each other at intervals, and the boring hole is arranged between the above-ground pipe for the sending side and the above-ground pipe for the return side. It is characterized by being done. In addition, in this Patent Document 1, there is a description that "above ground" means not only above the ground surface but also when it is buried in the ground about 1 to 2 m above the ground surface, for example.

Japanese Patent No. 5996238

In the piping system disclosed in Patent Document 1 described above, the sending-side ground piping and the return-side ground piping are arranged substantially parallel to each other at intervals, and the sending-side ground piping and the return-side ground piping are arranged substantially in parallel. A boring hole is arranged between and. That is, the ground pipe for the sending side and the ground pipe for the return side are buried at the same height position substantially parallel to the ground surface about 1 to 2 m across the boring hole.

However, depending on the construction site, it is difficult to arrange the feed side ground pipe and the return side ground pipe at the same height position with the boring hole in between, so that the feed side ground pipe is not sandwiched. In some cases, the pipe and the ground pipe for the return side must be arranged substantially in parallel and at different height positions. In this case, it is buried in the feed side underground pipe connecting the feed side ground pipe or the feed side ground pipe and the tube buried in the boring hole, and the return side ground pipe or the return side ground pipe and the boring hole. The return side underground pipe that connects to the tube may intersect in the ground.

It is not limited to this ground source heat pump system, but when the pipes are crossed in the ground, it is widely and generally sandblasted by ejecting liquid (water, etc.) in the ground in the unlikely event that the pipes are damaged. Even if this occurs, a certain space should be left between the pipes to prevent damage to other undamaged pipes and to prevent the pipes from rubbing against each other (separation). Take) need. In order to open a certain space between such pipes, the excavation depth and the excavation area are widened, which is not preferable because the excavation cost increases.

The present invention has been developed in view of the above-mentioned problems, and an object of the present invention is a pipe protection structure that can be particularly suitably applied to a ground source heat pump system, and two or more pipes. It is to provide a pipe protection structure that protects these pipes from sandblasting in the intersection area where the pipes intersect in the ground.

In order to achieve the above object, the pipe protection structure according to the present invention takes the following technical measures.
That is, the pipe protection structure according to the aspect according to the present invention is a pipe protection structure used for pipes buried in the ground, and the pipes are blasted from sandblasting in an intersection region where two or more pipes intersect in the ground. A protective member for protection is provided between the two or more pipes.

Preferably, the protective member can be configured to be fixed to the pipe.
More preferably, the protective member can be configured to be provided on the upper pipe and the lower pipe.
More preferably, the protective member can be configured to be provided in contact with the pipe.

More preferably, the protective member has a holding shape along a part of the cross-sectional shape of the pipe and has a three-dimensional shape having a predetermined length in the longitudinal direction of the pipe, and the holding shape portion of the pipe has a holding shape. Can be configured to be in contact with each other.
More preferably, the protective member is further provided with a contact surface on the opposite surface of the holding shape so that the contact surfaces of the protective members provided in the two or more pipes are in contact with each other. be able to.

More preferably, it further includes a holding member for holding the protective member in the pipe.
Each of the two or more pipes may be configured such that the protective members held by the holding members are provided in contact with each other or separated from each other.
More preferably, at least the material on the pipe side of the protective member can be configured to be made of a material softer than the pipe.

The pipe protection structure according to another aspect of the present invention is an underground pipe in which a tube forming a set of a heat collecting pipe and a heat radiating pipe for heat exchange is buried in the ground with the axial direction facing up and down. In the pipe protection structure used in the piping system including It is characterized in that it is provided between the above connecting pipes.

According to the present invention, it is a pipe protection structure that can be particularly suitably applied to a ground source heat pump system, and is a pipe protection structure that protects these pipes from sandblasting in an intersection region where two or more pipes intersect in the ground. Can be provided.

It is a perspective view which shows a part of the pipe structure in the geothermal heat pump system 10 which is an example to which the pipe protection structure which concerns on this invention is preferably applied. FIG. 3 is a plan view and a cross-sectional view of a piping structure in the geothermal heat pump system 10 shown in FIG. It is a perspective view and the side view which shows the pipe protection structure 100 which concerns on 1st Embodiment of this invention. It is a perspective view and the side view which shows the pipe protection structure 200 which concerns on 2nd Embodiment of this invention. It is a perspective view and the side view which shows the pipe protection structure 300 which concerns on 3rd Embodiment of this invention.

Hereinafter, the pipe protection structure according to the present invention will be described in detail with reference to the drawings. Since the pipe protection structure according to the present invention can be suitably applied to the geothermal heat pump system 10 without limitation, the pipe protection structure according to the present invention is applied to the geothermal heat pump system 10. The part to be done will be explained. In this explanation, first, the piping structure of the geothermal heat pump system 10 will be described.

<Geothermal heat pump system 10>
FIG. 1 is a perspective view showing a part of the piping structure in the ground source heat pump system 10, and 2B-2B cross sections in FIGS. 2 (A) and 2 (A) which are plan views of the piping structure shown in FIG. The piping structure in the ground source heat pump system 10 will be described with reference to FIG. 2 (B), which is a diagram.

The geothermal heat pump system 10 is applied to a heat exchanger (heat collecting tube / heat radiating tube) 90 connected to a heat pump 20 provided indoors or outdoors.
Specifically, this underground heat pump system 10 is embedded in a state in which a heat exchanger 90 is inserted into a boring hole 30 drilled in the ground in the vertical direction Y, and the heat exchangers 90 are buried in each other. It is connected to the heat pump 20 via a feed-side underground pipe 50 and a return-side underground pipe 70 extending in parallel. Here, in FIGS. 1 and 2, the direction of the feed side of the heat medium flowing from the heat pump 20 on the ground to the lower end of the heat exchanger 90 underground is set as the feed direction S (Supply), and from the lower end of the heat exchanger 90. The direction on the return side of the heat medium flowing up to the heat pump 20 is shown as the return direction R (Reverse).

The feed-side underground pipe 50 is a pipe for circulating a heat medium (fluid) from the heat pump 20 to the feed-side tube 66 of the heat exchanger 90. On the other hand, the return-side underground pipe 70 is a pipe for circulating the heat medium from the return-side tube 86 toward the heat pump 20. The sending side underground pipe 50 and the return side underground pipe 70 are arranged substantially parallel to each other with a distance (here, ΔL), and are connected to the sending side underground pipe 50 (connected to the return side underground pipe 70). The first branch pipe 76 on the return side is arranged so as to intersect with the first branch pipe 76 on the return side at an interval (ΔH in this case) above and below the intersection region C in the ground, and either the underground pipe 50 on the feed side or the underground pipe 70 on the return side. A boring hole 30 (heat exchanger 90) is arranged on one side (meaning that it is not between the two). The pipes shown in the figure including the underground pipe 50 on the sending side and the underground pipe 70 on the return side (excluding the depth of the boring hole 30) are buried in the ground about 1 to 2 m from the ground surface, for example. ..

Then, for example, when used for indoor heating, the cold heat medium circulates in the feed direction S in the feed side underground pipe 50, and the heat medium collected by the heat exchanger 90 in the return side underground pipe 70. Is distributed in the return direction R.
The heat exchanger 90 is provided with two sets of a pair of feed-side tubes 66 and return-side tubes 86 made of a resin tube such as polyethylene (PE), and these four feed-side tubes 66 and return-side tubes 86 are provided, respectively. The first underground side joint 68 and the second underground joint 68 are arranged so that the axial direction of the pipe is vertically oriented along the boring hole 30 and two lower ends of the feed side tube 66 and the return side tube 86 are connected to each other. It is composed of a side joint 88, a first ground side joint 64 (pipe joint) and a second ground side joint 84 (pipe joint) that connect two upper ends to each other.

The first underground side joint 68 connects the lower ends of the feed side tube 66 (not connected to the second underground side joint 88) and the return side tube 86 of the four tubes, respectively. On the other hand, the second underground side joint 88 connects the lower ends of the feed side tube 66 and the return side tube 86 (not connected to the first underground side joint 68) of the four tubes, respectively. .. That is, when the heat pump 20 is used for heating, the heat medium (feeding direction S) that is sent from the sending side underground pipe 50 arranged on the ground and circulates in the sending side tube 66 is the first underground side joint. It passes through 68 (second underground side joint 88), passes through the return side tube 86 (return direction R), and is sent out toward the return side underground pipe 70. At this time, heat exchange is performed between the feed side tube 66 and the return side tube 86 in the ground.

The first ground side joint 64 connects the upper ends of the feed side tubes 66 of the four tubes, respectively. On the other hand, the second ground side joint 84 connects the upper ends of the return side tubes 86 of the four tubes, respectively. That is, the heat medium (feeding direction S) sent from the underground feeding side underground pipe 50 circulates in the sending side tube 66 from the first ground side joint 64, and flows through the first underground side joint 68 (second underground side joint 68). It passes through the underground side joint 88), passes through the return side tube 86 (return direction R), and is sent out from the second ground side joint 84 toward the return side underground pipe 70.

As shown in FIGS. 1 and 2, the heat medium is circulated through the feed side underground pipe 50 and the return side underground pipe 70 one by one through the plurality of boring holes 30 (heat exchanger 90). As for the feed side, the feed side cheese 52, the feed side socket 54, the feed side first branch pipe 56, the feed side first elbow 58, the feed side second branch pipe 60, and the feed side second elbow 62 are routed. The first ground side joint 64 is connected to the sending side underground pipe 50, and for the return side, the return side cheese 72, the return side socket 74, the return side first branch pipe 76, the return side first elbow 78, and the return side. The second ground side joint 84 is connected to the return side underground pipe 70 via the second branch pipe 80 and the return side second elbow 82. The cheese is a T-shaped pipe joint, and the elbow is an L-shaped pipe joint.

With such a configuration, in the heat exchanger 90, the heat medium fed from the first ground side joint 64 passes through the first ground side joint 64 and is delivered into the pair of feed side tubes 66. On the other hand, the heat medium sent from the pair of return-side tubes 86 passes through the second ground-side joint 84 and is sent out to the return-side underground pipe 70. Then, heat exchange is performed in the process of the heat medium passing through the feed side tube 66 and the return side tube 86.

Therefore, by configuring the geothermal heat pump system 10 using such a heat exchanger 90, the geothermal heat pump system 10 can be constructed, and the room can be effectively cooled and heated.
In the ground source heat pump system 10 having the above piping structure, as described above, tubes (feed side tube 66 and return side tube 86) forming a set of a heat collection tube and a heat dissipation tube for heat exchange are performed. ) Includes underground pipes buried in the ground with the axial direction facing the vertical direction (vertical direction Y). Then, in a part of this underground pipe, there is an intersection region C in which two or more connecting pipes intersect at the top and bottom of the ground. More specifically, as shown in FIGS. 1 and 2, in this geothermal heat pump system 10, the sending side underground pipe 50 (lower side) and the return side first branch pipe 76 (upper side) at the intersection region C. Crosses above and below the ground. The underground pipe 50 on the sending side and the first branch pipe 76 on the returning side intersect at right angles above and below the ground, but the intersection region C to which the pipe protection structure according to the present invention is applied is the ground. It is not limited to the pipes that intersect at right angles at the top and bottom of the inside, and may be any pipe that intersects underground, or any pipe that intersects two or more pipes underground.

<Piping protection structure>
In the following, the pipe protection structure according to the present invention, which is suitably applied to such an intersection region C, is the pipe protection structure 100 according to the first embodiment and the pipe protection structure 200 according to the second embodiment. And the pipe protection structure 300 according to the third embodiment will be described separately.
-Piping protection structure 100 according to the first embodiment
With reference to FIG. 3, in the pipe protection structure 100 according to the first embodiment, at least one of the upper protection member 110 and the lower protection member 120 that protects two or more intersecting pipes in the intersection region C from sandblasting is provided. It is characterized in that it is provided between two or more pipes.

The upper protective member 110 and the lower protective member 120 have a three-dimensional shape having an upper holding shape 112 and a lower holding shape 122 along a part of the cross-sectional shape of the pipe and having a predetermined length in the longitudinal direction of the pipe. To be equipped. These upper protective member 110 and lower protective member 120 have the same shape (however, the pipe diameter may be different). Since the cross-sectional shape of the pipe is circular, the cross-sectional shapes of the upper holding shape 112 of the upper protective member 110 and the lower holding shape 122 of the lower protective member 120 follow half of the circle (semicircle). The shape. That is, these upper protective member 110 and lower protective member 120 have a shape in which one side of a rectangular parallelepiped is cut by half a cylinder. Then, the pipes are provided in contact with the portions of the upper holding shape 112 and the lower holding shape 122. As a result, the upper protective member 110 is fixed to the return side first branch pipe 76, and the lower protective member 120 is fixed to the feed side underground pipe 50, respectively.

Further, these upper protective member 110 and lower protective member 120 further include an upper contact surface 114 and a lower contact surface 124 on opposite surfaces of the upper holding shape 112 and the lower holding shape 122. That is, these upper protective member 110 and lower protective member 120 have a shape in which one side of a rectangular parallelepiped is cut by a cylinder having a semicircular cross section, and the opposite side of the cut surface is a flat upper contact. A surface 114 and a lower contact surface 124 are formed. When the upper protective member 110 and the lower protective member 120 are provided on the two or more pipes, the contact surfaces (upper contact surface 114 and lower contact surface 124) come into contact with each other. The pipe protection structure 100 is formed.

As described above, the pipe protection structure 100 is a return in which protective members (upper protective member 110 and lower protective member 120) shaped like a so-called "tube pillow" intersect vertically in the ground in the intersection region C. The first branch pipe 76 on the side is provided with the upper protective member 110, and the underground pipe 50 on the sending side is provided with the lower protective member 120. If the contact surfaces (upper contact surface 114 and lower contact surface 124), which are the bottom surfaces of the so-called "tube pillow", are brought into contact with each other to construct a pipe protection structure, these pipes have a holding shape (upper side). It is preferable in that it is not necessary to separately fix the (so-called) "tube pillow" to the pipe because it is restrained by the holding shape 112 and the lower holding shape 122).
-Piping protection structure 200 according to the second embodiment
With reference to FIG. 4, in the pipe protection structure 200 according to the second embodiment, at least one of the upper protection member 210 and the lower protection member 220 that protects two or more intersecting pipes in the intersection region C from sandblasting is provided. It is characterized in that it is provided between two or more pipes.

As will be described later, these upper protective member 210 and lower protective member 220 are made of a soft material and are wound around half the circumference of the outer diameter of the pipe, so that they are part of the cross-sectional shape of the pipe. It will have a holding shape along it. Further, as in the first embodiment, the upper protective member 210 and the lower protective member 220 have a three-dimensional shape (thin rectangular parallelepiped shape) having a predetermined length in the longitudinal direction of the pipe. These upper protective member 210 and lower protective member 220 have the same shape. Then, a pipe is provided in contact with the upper protective member 210 and the lower protective member 220. Further, the upper holding member 212 and the lower holding member 222 such as a band for one circumference of the outer diameter of the pipe for holding the upper protective member 210 and the lower protective member 220 in the pipe are further included to hold the upper side. Member 2
The upper protective member 210 is fixed to the return-side first branch pipe 76, and the lower protective member 220 is fixed to the feed-side underground pipe 50 by the 12 and the lower holding member 222. In the pipe protection structure 200, the upper protection member 210 and the lower protection member 220 are provided with a distance G (G> 0) (that is, separated from each other).

Further, it is also preferable to provide a protrusion 230 on the lower protective member 220 so that the lower holding member 222 formed of such a band or the like does not slip off from the lower protective member 220. Although not shown, the upper protective member 210 may be provided with a protrusion (same configuration as the protrusion 230) so that the upper holding member 212 formed of such a band or the like does not slip off from the upper protective member 210. preferable. In this way, since the lower holding member 222 does not slip off from the lower protective member 220, the upper holding member 212 is displaced from the upper protective member 210 so that the lower protective member 220 does not come off from the sending side underground pipe 50. Since it does not fall, the pipe protection structure 200 can be formed so that the upper protection member 210 does not come off from the return side first branch pipe 76.
-Piping protection structure 300 according to the third embodiment
With reference to FIG. 5, in the pipe protection structure 300 according to the third embodiment, at least one of the upper protection member 210 and the lower protection member 220 that protects two or more intersecting pipes in the intersection region C from sandblasting is provided. It has the same configuration as the pipe protection structure 200 according to the second embodiment except that it is provided between two or more pipes, except for the following points. In the above-mentioned pipe protection structure 200, the upper protection member 210 and the lower protection member 220 are provided apart from each other (with a distance G apart), but in this pipe protection structure 300, the upper protection member 210 and the upper protection member 210 are provided. The only difference is that it is provided in contact with the lower protective member 220 (distance G = 0).

The point that the upper protective member 210 and the lower protective member 220 are provided in contact with each other (distance G = 0) in the pipe protection structure 300 according to the third embodiment is related to the second embodiment. It is different from the pipe protection structure 200 and is similar to the pipe protection structure 100 according to the first embodiment.
As described above, in the pipe protection structure 300 in which the protective members are in contact with each other and the pipe protection structure 200 in which the protective members are not in contact with each other apart from each other, protection such as a half-split pipe that fits perfectly with the pipe to be protected is protected. The member is fixed to the pipe by a holding member. As the holding member, as described above, a band is particularly preferable, and a binding band is particularly preferable. Here, it should be noted that the adhesive component may adversely affect the piping resin in the case of tape or the like instead of such a binding band.
-At least the material on the piping side of the protective member The piping protection structure 100 according to the first embodiment, the piping protection structure 200 according to the second embodiment, and the piping protection structure according to the third embodiment described above. In common with 300, at least the material on the pipe side of the protective member is made of a material softer than the pipe to be protected. For example, the following material, which is a softer material so that the high-density polyethylene (high-density PE), which is the material of the piping used in the intersection region C in the above-mentioned geothermal heat pump system 10, is not damaged. Can be mentioned. For example, such materials include rubber, medium-density polyethylene, low-density polyethylene, and wood (sugi, balsa, etc., which are generally considered to be soft and easily available, although the hardness varies depending on the type). Further, even if it is a hard material such as metal, the pipe side may be covered with the above-mentioned soft material. In this respect, at least the material on the piping side of the protective member may be softer than the material of the piping to be protected.

In addition to such softness (flexibility), the thickness is also an issue to prevent sandblasting. That is, the required thickness changes depending on the softness of the material, and the softer the material, the thinner the material, and the harder the material, the thicker the material. For example, rubber may have a thickness of about 3 mm, but medium-density polyethylene, which is harder than rubber, has a thickness of about 10 mm. It is preferable that the type of these materials and their thickness and the like are determined depending on the balance of protection time required in consideration of the durability while realizing sufficient resistance to sandblasting.

As described above, according to the pipe protection structure according to the present embodiment, the following effects are exhibited.
(1) Since a protective member is provided between the two or more pipes in the intersection region C where two or more pipes intersect at the top and bottom of the ground, the protective member provides a liquid in the ground in the unlikely event that the pipes are damaged. Even if sandblasting occurs due to the ejection of (water, etc.), it is possible to prevent damage to other undamaged pipes and prevent rubbing between pipes. As a result, it is not necessary to open a certain space (separate) between the pipes, and the excavation depth and the excavation area do not increase, so that an increase in excavation cost can be suppressed.
(2) If a protective member is fixed to a pipe between two or more pipes in an intersection area C where two or more pipes intersect at the top and bottom of the ground, liquid (water, etc.) should be provided if the pipe is damaged. Since the protective member is fixed to the pipe even if it blows out and hits the protective member, the protective member does not shift or flow, so that the pipe can be suitably protected from sandblasting in the intersection region C.
(3) If a protective member is provided for each of the two or more pipes in the intersection area C where two or more pipes intersect at the top and bottom of the ground (provided for all the pipes to be protected), the pipes should be damaged by any chance. Even if the protective member is damaged (especially when the protective member is in close contact with the pipe), the protective member of the other pipe (undamaged pipe) is installed without being damaged. The pipe can be suitably protected from sandblasting in the intersection region C.
(4) If a protective member is provided in contact with each of the two or more pipes in the intersection region C where two or more pipes intersect at the top and bottom of the ground, earth and sand do not enter between the pipes and the protective member. The piping can be suitably protected from sandblasting in the region C. That is, if there is earth and sand between the pipe and the protective member, it causes a deviation between the pipe and the protective member. There is no deviation.

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The present invention is particularly preferable for a pipe protection structure that protects these pipes from sandblasting in an intersection region where two or more pipes intersect at the top and bottom of the ground, and is particularly preferable in that it can be suitably applied to a geothermal heat pump system. ..

10 Underground heat heat pump system 20 Heat pump 30 Boring hole 50 Feed side underground piping 70 Return side underground piping 90 Heat exchanger 100 Piping protection structure according to the first embodiment 200 Piping protection according to the second embodiment Structure 300 Piping protection structure according to the third embodiment

Claims (8)

A pipe protection structure used in a piping system including underground pipes in which a set of heat collecting pipes and heat radiation pipes for heat exchange is buried in the ground with the axial direction facing up and down. ,
In an intersection area where two or more connecting pipes connected to the underground pipe intersect in the ground, a protective member for protecting the connecting pipe from sandblasting is provided between the two or more connecting pipes. Piping protection structure . The pipe protection structure according to claim 1, wherein the protection member is fixed to the connection pipe. The pipe protection structure according to claim 1 or 2, wherein the protective member is provided on the upper connection pipe and the lower connection pipe. The pipe protection structure according to any one of claims 1 to 3, wherein the protection member is provided in contact with the connection pipe. The protective member is provided with a three-dimensional shape having a predetermined length in the longitudinal direction of the connecting pipe provided with a retention shape along a portion of the cross-sectional shape of the connection pipe,
The pipe protection structure according to claim 4, wherein the connecting pipe is provided in contact with the holding shape portion. The protective member further includes a contact surface on the opposite surface of the holding shape.
The pipe protection structure according to claim 5, wherein the contact surfaces of the protective members provided on the two or more connecting pipes are in contact with each other. A holding member for holding the protective member in the connecting pipe is further included.
The pipe protection structure according to claim 5, wherein the protective members held by the holding members are provided in contact with or separated from each other in each of the two or more connecting pipes. The pipe protection structure according to any one of claims 1 to 7, wherein at least the material on the connecting pipe side of the protective member is made of a material softer than the connecting pipe.

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