JP7751872B2 - Pipe end members and pipe structures - Google Patents

Description

This relates to a pipe end member installed at the end of a double-structure pipe consisting of an outer pipe and an inner pipe, and a pipe structure equipped with this pipe end member.

When existing pipes such as industrial water pipes, agricultural water pipes, drinking water pipes, and gas pipes become deteriorated or the pipe walls become damaged, a lining pipe is sometimes installed inside the existing pipe to line the inner surface of the pipe wall (see, for example, Patent Document 1). In this case, there is a risk that pressurized fluid flowing inside the lining pipe will penetrate into the small gap that occurs between the existing pipe and the lining pipe, causing corrosion of the existing pipe. For this reason, pipe end members have traditionally been installed to prevent pressurized fluid from penetrating into this gap.

Figure 1 is a cross-sectional view showing a conventional method of installing a pipe end member.

1 shows only the upper cross-section of an existing outer pipe 91 and an inner pipe 92, a lining pipe lining the inner surface of the outer pipe 91. In this Figure 1, the pipe end 911 of the outer pipe 91 is shown on the left side of the figure, with the left side being the pipe end side and the right side being the rear side. As shown in Figure 1(a), the inner pipe 92 is positioned on the inner surface 91i side of the outer pipe 91. The inner pipe 92 is formed by inflating it within the outer pipe 91 and hardening it while pressing it against the inner surface of the outer pipe 91. When the inner pipe 92 is fully formed (hardened), its end 921 typically protrudes further toward the end than the end 911 of the outer pipe 91. Therefore, as shown in Figure 1(b), the protruding portion of the inner pipe 92 is first cut off using an electric saw or similar tool so that the position of the end 921 of the inner pipe 92 roughly aligns with the position of the end 911 of the outer pipe 91. Then, as shown in Figure 1(c), the portion of the inner tube 92 facing the tube end 921 is scraped off with a grinder or cut with an electric cutter and peeled off from the outer tube 91 so that the tube end 921 of the inner tube 92 is positioned approximately 50 cm further back than the tube end 911 of the outer tube 91.

After the portion of the inner pipe 92 facing the pipe end 921 has been removed, a cylindrical rubber packing member 931 is attached from the end of the inner circumferential surface 91i of the outer pipe 91 to the end of the inner circumferential surface 92i of the inner pipe 92. The packing member 931 is attached to the entire inner circumferential surface 91i of the outer pipe 91 and the entire inner circumferential surface 92i of the inner pipe 92, although only the upper cross-section of the packing member 931 is shown in Figure 1(c). Similarly, the entire circumference of the portion of the inner pipe 92 facing the pipe end 921 has been removed, but only the upper cross-section of the inner pipe 92 is shown in Figure 1(c). The packing member 931 shown in Figure 1(c) is attached so that the pipe end edge 9311 of the cylindrical packing member 931 is aligned with the pipe end 911 of the outer pipe 91.

The packing member 931 is simply attached by hand, and the seal between the outer pipe 91 and the inner pipe 92 is insufficient. Therefore, an expansion band 932 is used to press the packing member 931. The expansion band 932 is C-shaped and made of stainless steel, and is installed sequentially from the back toward the pipe end. To fit the expansion band 932 from the inside, the C-shaped expansion band 932 is expanded with an expansion tool (not shown), and a fixing plate (not shown) that closes the gap in the C-shape is inserted. By inserting the fixing plate, the expansion band 932 remains expanded even after the expansion tool is removed, and presses the packing member 931 outward. The fixing plate that closes the C-shaped gap is inserted while being struck with a hammer from the pipe end toward the back. The impact of hitting with the hammer inevitably causes the packing member 931 to shift toward the rear along with the expansion band 932 (see the arrow in Figure 1(d)). Furthermore, if multiple expansion bands 932 are fitted in order from the rear, the packing member 931 will shift toward the rear each time a new expansion band 932 is fitted.

Figure 1(d) shows the state after the expansion bands 932 have been fitted in four locations and the installation of the pipe end member 93 has been completed. In the state shown in Figure 1(d), the packing member 931 has shifted to the rear, exposing a portion of the inner circumferential surface 91i of the outer pipe 91 approximately 15 cm from the pipe end 911.

Figure 1(e) shows one end of a coupling member 95 connected to the outer peripheral surface 91o of the outer pipe 91. Another pipe is connected to the other end of the coupling member 95 shown in Figure 1(e), and pressurized fluid flows through the outer pipe 91, which has an inner pipe 92 attached to its inner peripheral surface 91i.

Japanese Patent Application Publication No. 11-179804

However, the task of scraping or peeling off the pipe end 921 side portion of the inner pipe 92 from the outer pipe 91 is a complicated task that requires a worker to carefully insert a tool such as a grinder or electric cutter into the inside of the inner pipe 92 while taking care not to damage the outer pipe 91, resulting in poor workability.

In view of the above circumstances, the present invention aims to provide a pipe end member that is easy to install and a pipe structure that includes the pipe end member.

The tube end member of the present invention that solves the above object comprises:
A pipe end member to be installed at the end of a double-structure pipe having an outer pipe and an inner pipe,
a hollow disk-shaped flange portion extending across both an outer pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the outer pipe and an inner pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the inner pipe;
a cylindrical portion formed continuously with the flange portion and covering the entire circumference of an end portion of an inner circumferential surface of the inner pipe;
a pressing member that presses the cylindrical portion toward an inner circumferential surface of the inner tube;
The present invention is characterized in that it includes a fixing plate that increases the pressing force of the pressing member toward the inner circumferential surface of the inner tube while pressing the pressing member toward the inner side of the inner tube.
Also, a pipe end member to be installed at the end of a double-structure pipe having an outer pipe and an inner pipe,
a hollow disk-shaped flange portion extending across both an outer pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the outer pipe and an inner pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the inner pipe;
a cylindrical portion formed continuously with the flange portion and covering the entire circumference of an end portion of an inner circumferential surface of the inner pipe;
The housing may further include a pressing member that presses the cylindrical portion toward the inner peripheral surface of the outer tube.
Also, a pipe end member to be installed at the end of a double-structure pipe having an outer pipe and an inner pipe,
The outer pipe may have a hollow disk-shaped flange portion extending across both an outer pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the outer pipe and an inner pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the inner pipe .

With this pipe end member, the flange portion can close the small gap between the end of the outer pipe and the end of the inner pipe, preventing the pressurized fluid flowing through the double-walled pipe from entering the gap. This eliminates the need to scrape or strip the end portion of the inner pipe, reducing the complicated work involved in installing this pipe end member and improving workability.

In addition to being used for double-structure pipes in which the outer pipe is an existing pipe and the inner pipe is a lined pipe, the pipe end member of the present invention can also be used for double-structure pipes consisting of a new outer pipe and a new inner pipe, which may or may not be lined.

It is preferable that this tube end member be extensible or elastically deformable.

In addition, in the above-mentioned pipe end member,
The inner pipe may further include a cylindrical portion formed continuously with the flange portion and covering the entire periphery of the end portion of the inner circumferential surface of the inner pipe.

By inserting the cylindrical portion into the inner circumferential surface of the inner pipe, the flange portion can be positioned to extend across both the outer pipe thickness surface and the inner pipe thickness surface, further improving the ease of installation of this pipe end member. Furthermore, the presence of the cylindrical portion makes it difficult for pressurized fluid to enter between the flange portion and the inner pipe thickness surface, thereby improving the sealing performance of this pipe end member.

The cylindrical portion and the flange portion may be integrally molded, or may be formed by joining separate molded portions. The cylindrical portion may also be pressed against the entire circumference of the end of the inner circumferential surface of the inner pipe. Furthermore, the inner pipe thickness surface may be a surface positioned generally in line with the outer pipe thickness surface in the extension direction of the outer pipe.

Furthermore, a pressing member may be provided that presses the cylindrical portion toward the inner circumferential surface of the inner tube. The force with which the pressing member presses the cylindrical portion toward the inner circumferential surface of the inner tube may increase as the pressing member is pushed inward.

The tubular structure of the present invention that solves the above object comprises:
Existing buried pipes and
a lining pipe lining the inner circumferential surface of the existing pipe;
a pipe end member disposed at an end of the lining pipe,
The pipe end member is characterized by comprising: a hollow disk-shaped flange portion extending across both the existing pipe thickness surface between the outer peripheral surface and inner peripheral surface at the pipe end of the existing pipe and the lining pipe thickness surface between the inner peripheral surface and outer peripheral surface at the pipe end of the lining pipe; a cylindrical portion formed contiguous with the flange portion and covering the entire end circumference of the inner peripheral surface of the lining pipe; a pressing member that presses the cylindrical portion toward the inner peripheral surface of the lining pipe; and a fixing plate that increases the pressing force of the pressing member toward the inner peripheral surface of the lining pipe while pressing the pressing member toward the back side of the lining pipe.
In addition, with existing buried pipes,
a lining pipe lining the inner circumferential surface of the existing pipe;
a pipe end member disposed at an end of the lining pipe,
The pipe end member may have a hollow disk-shaped flange portion extending across both the existing pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the existing pipe and the lining pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the lining pipe, a cylindrical portion formed continuously with the flange portion and covering the entire circumference of the end portion on the inner peripheral surface of the lining pipe, and a pressing member pressing the cylindrical portion against the inner peripheral surface of the lining pipe .
In addition, with existing buried pipes,
a lining pipe lining the inner circumferential surface of the existing pipe;
a pipe end member disposed at an end of the lining pipe,
The pipe end member may have a hollow disk-shaped flange portion extending across both the existing pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the existing pipe and the lining pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the lining pipe.

This pipe structure has the pipe end member of the present invention and can be installed without scraping or stripping off the end portion of the lining pipe, making it easy to install. The existing pipe may also have been used as an internal pressure pipe.

In addition, in the above-mentioned tubular structure,
The pipe end member may have a cylindrical portion formed continuously with the flange portion and covering the entire periphery of the end portion on the inner peripheral surface of the lining pipe.

When constructing this pipe structure, the flange portion is positioned in the specified position by inserting the cylindrical portion into the inner surface of the lining pipe, further improving the ease of construction of this pipe end member. Furthermore, the presence of the cylindrical portion makes it difficult for pressurized fluid to enter between the flange portion and the lining pipe thickness surface, thereby improving sealing performance.

Here, the cylindrical portion may be pressed against the entire circumference of the end of the inner circumferential surface of the lining pipe. The pipe end member may have a pressing member that presses the cylindrical portion toward the inner circumferential surface of the lining pipe. The pressing member may be configured such that the force pressing the cylindrical portion toward the inner circumferential surface of the lining pipe increases as it is pressed inward.

In addition, in the above-mentioned tubular structure,
A cylindrical joint member is provided to connect the end of the existing pipe and the end of the separate pipe,
the coupling member has an annular protrusion that protrudes annularly inward from an inner circumferential surface of the coupling member,
The flange portion may be pressed against at least one of the thickness surface of the existing pipe and the thickness surface of the lining pipe by the annular protrusion.

In other words, the flange portion may be sandwiched between the annular protrusion and at least one of the existing pipe thickness surface and the lining pipe thickness surface. The flange portion is pressed by the annular protrusion, thereby improving the sealing performance of the pipe end member.

In addition, a water-stopping material or adhesive may be filled between the thickness surface of the existing pipe and the flange portion. Also, a water-stopping material or adhesive may be filled between the thickness surface of the lining pipe and the flange portion.

The present invention provides a pipe end member that is easy to install and a pipe structure that includes the pipe end member.

FIG. 10 is a cross-sectional view showing a conventional method for installing a pipe end member. FIG. 1 is a plan view schematically showing a site where a tubular structure is constructed. 10A is a flowchart showing a pipe structure construction method, and FIG. 10B is a flowchart showing in detail the pipe end member installation process (step S80) shown in FIG. FIG. 4 is a cross-sectional view schematically illustrating a state in which the lining pipe heating (step S60) shown in FIG. 3(a) is being performed. FIG. 4 is a cross-sectional view showing the state in which the pipe end member of the present embodiment is installed. FIG. 4 is a cross-sectional view showing how a joint member is installed on the outer peripheral surface of a double pipe. 6(a) is a cross-sectional view similar to FIG. 6(c) showing a first modified example of the pipe end member and the pipe structure, and FIG. 6(b) is a cross-sectional view similar to FIG. 6(c) showing a second modified example of the pipe structure. 6(a) is a cross-sectional view similar to FIG. 6(c) showing a third modified example of the tubular structure, and FIG. 6(b) is a cross-sectional view similar to FIG. 6(c) showing a fourth modified example of the tubular structure.

An embodiment of the present invention will now be described with reference to the drawings. In this embodiment, an example will be given in which a pipe structure is constructed by lining a portion of an aging pipe that has been used as an internal pressure pipe and then connecting it to a new pipe.

Figure 2 is a schematic plan view of the construction site for the pipe structure.

Figure 2 shows the scene around intersection IS, where a wide road R1 runs vertically and a narrow road R2 runs horizontally. Wide road R1 has a lot of traffic, making it difficult to close the road or restrict lanes. On the other hand, narrow road R2 has little traffic, making it easy to close the road.

The deteriorated pipe EP runs underneath and along the narrow road R2. Therefore, at intersection IS, it runs across underneath the wide road R1. In Figure 2, the left side is the upstream side and the right side is the downstream side.

Figure 3(a) is a flowchart showing a method for constructing a tubular structure.

In the pipe structure construction method shown in Figure 3(a), first, a new pipe is buried to replace the aged pipe EP (step S10). At the site shown in Figure 2, the narrow road R2 is closed to traffic, and a new pipe is buried alongside the aged pipe EP. The upstream new pipe NP1 is buried in the section of the narrow road R2 upstream of the intersection IS, and the downstream new pipe NP2 is buried in the section downstream of the intersection IS. In Figure 2, soil has been returned to the location where the upstream new pipe NP1 was buried, and soil has also been returned to the location where the downstream new pipe NP2 was buried. In Figure 2, the buried pipes are indicated by dashed double-dashed lines.

Because it is difficult to close roads or restrict lanes on wide road R1, it is not possible to bury a new pipe within intersection IS. Instead, the existing pipe is left buried without being excavated, and a new lining pipe is installed on the inner surface of the existing pipe. The lining pipe is sometimes inserted in reverse into the existing pipe, and sometimes pulled in. When a lining pipe is passed through an existing pipe, the entrance side is referred to as the departure side, and the exit side is referred to as the arrival side. Either the upstream or downstream side relative to intersection IS is the departure side, and the other side is the arrival side. In the following explanation, the upstream side relative to intersection IS is referred to as the departure side, and the downstream side relative to intersection IS is referred to as the arrival side.

In step S20, which follows step S10, a starting-side vertical hole VH1 is excavated at a position offset upstream from the intersection IS, and a destination-side vertical hole VH2 is excavated at a position offset downstream from the intersection IS. Note that either the starting-side vertical hole VH1 or the destination-side vertical hole VH2 may be excavated first, or they may be excavated simultaneously. Also, either step S10 or step S20 may be performed first, or they may be performed simultaneously. In Figure 2, the edges of the vertical holes VH1 and VH2 are indicated by long dashed lines. By providing the upstream vertical hole VH1, the downstream end of the upstream new pipe NP1 is excavated, and the portion of the aged pipe EP upstream of the intersection IS is also excavated. Furthermore, by providing the downstream vertical hole VH2, the upstream end of the downstream new pipe NP2 is excavated, and the portion of the aged pipe EP downstream of the intersection IS is also excavated.

In the following step S30, the aged pipe EP excavated in the vertical holes VH1 and VH2 is cut in each of the vertical holes VH1 and VH2, and a portion of the aged pipe EP is removed. Hereinafter, the portion of the aged pipe EP whose ends are separated by removing the portion of the aged pipe EP will be referred to as the existing pipe EPL. The existing pipe EPL is buried underground at the intersection IS, with its ends opening into the vertical holes VH1 and VH2. In Figure 2, the cross-hatched portions indicate the removed portions. This step S30 involves cutting out the existing pipe EPL to be fitted with the lining pipe, thereby forming the starting end and the destination end. The upstream aged pipe EP1 remains buried upstream of the existing pipe EPL, and the downstream aged pipe EP2 remains buried below the existing pipe EPL. Both the upstream aged pipe EP1 and the downstream aged pipe EP2 will remain buried without being removed.

In step S40, the lining pipe is pulled into the existing pipe EPL.

Here, the lining pipe will be described in detail. The lining pipe is a cylindrical pipe impregnated with an uncured curable resin (e.g., thermosetting resin, photocurable resin, etc.) and is prepared in advance at the factory using the following procedure. In this embodiment, a lining pipe impregnated with thermosetting resin will be described as an example. Note that a lining pipe impregnated with photocurable resin is formed using the same procedure as a lining pipe impregnated with thermosetting resin, except that light is irradiated instead of heat in step S60, described below. First, a cylindrical base hose having an outer film layer on the outside and a substrate layer on the inside of the outer film layer, and a cylindrical calibration hose having an extensible layer on the outside and a substrate layer on the inside of the extensible layer are separately prepared, and each substrate layer is impregnated with thermosetting resin. Next, the calibration hose is inverted and inserted inside the thermosetting resin-impregnated base hose at the factory. Inverting involves inserting the calibration hose inside the base hose, with the base layer facing inward, into the base hose. The calibration hose is inserted into the base hose from one end and then inverted in the factory using air or water. Because the calibration hose is thinner than the base hose, inverting is easy. By inverting the calibration hose, the base layer of the base hose comes into contact with the base layer of the calibration hose, completing a lining pipe in which the two tubular components—the base hose and the calibration hose—are integrated. The outermost surface of the lining pipe is composed of an outer film layer, and the innermost surface is composed of an extension layer. A base layer impregnated with a thermosetting resin is positioned between the outer film layer and the extension layer. A steam supply tube is then inserted inside the extension layer to supply steam for heating the lining pipe. The completed lining pipe can be flattened and stored at low temperatures in a zigzag folded or rolled state. The lining pipe is transported to the construction site in a refrigerated truck in a folded or rolled state and is used in step S40.

In step S40, a winch (not shown) is installed in the vertical hole VH2 on the arrival side. Next, the rear end of the pull-in wire wound around the winch via a pulley is inserted from the arrival side end to the departure side end of the existing pipe EPL, and the pull-in wire is passed through the existing pipe EPL.

The leading end of the lining pipe is tied together with a bundling wire, and the trailing end of the pull-in wire that has been passed through to the starting end of the existing pipe EPL is connected to the bundling wire. The pull-in wire is wound up using a winch (not shown) installed in the vertical hole VH2 on the arrival side, and the lining pipe is pulled into the existing pipe EPL from its starting end. Once the pull-in wire has been wound up until the leading end of the lining pipe, tied together with the bundling wire, emerges from the arrival end of the existing pipe EPL, the winch is stopped and the pulling-in is complete.

In step S50, the bundling wire is removed from the lining pipe, and both open ends of the lining pipe that has penetrated the existing pipe EPL are sealed. A steam supply tube runs inside the lining pipe from the departure end to the arrival end. In step S50, room temperature air is supplied from the steam supply tube into the lining pipe, inflating the lining pipe and expanding its diameter. Once the lining pipe has sufficiently expanded, the outer film layer of the lining pipe is pressed against the inner surface of the existing pipe EPL.

Figure 4 is a cross-sectional view showing the lining pipe heating (step S60) shown in Figure 3(a) in a simplified manner, with the left side of the figure being the departure side and the right side being the arrival side. Figure 4 shows vehicles V1 and V2 travelling along a wide road to and from an intersection IS. It also shows a triangular cone TC to prevent vehicles from entering a narrow road R2.

Figure 4 also shows multiple cracks C1 to C4 that have occurred in the existing pipe EPL.

In addition, Figure 4 also shows the lining pipe LP, which has been expanded while passing through the existing pipe EPL. A steam supply tube 36 runs through the center of this lining pipe LP. The steam supply tube 36 shown in Figure 4 has round holes 362 with a diameter of approximately 1 cm at 1-meter intervals along its length, and a slit hole 361 with a width of several centimeters and a length of approximately 10 to 20 cm at its end. Furthermore, a starting-side jig 34 is disposed at the starting-side end of the lining pipe LP, and a reaching-side jig 35 is disposed at its end. The starting-side jig 34 includes a plug member 341, a starting-side clamping member 342, and a tube clamping member 343. The plug member 341 has a steam supply port 3411 and a steam exhaust port 3412. The plug member 341 is fixed to the starting-side open end of the lining pipe LP by a starting-side clamping member 342 and closes the starting-side opening of the lining pipe LP, except for the steam supply port 3411 and steam exhaust port 3412. The steam supply tube 36 is fixed to the steam supply port 3411 by a tube clamping member 343. The destination-side jig 35 includes a fastening drum 351 and a destination-side clamping member 352. The fastening drum 351 is a rigid cylindrical body. The destination-side end of the lining pipe LP and the destination-side end of the steam supply tube 36 are clamped to the outer circumferential surface of the rigid fastening drum 351 by the destination-side clamping member 352, sealing both the destination-side opening of the lining pipe LP and the destination-side opening of the steam supply tube 36. Note that the destination-side end of the lining pipe LP may be pre-closed. Similarly, the destination-side end of the steam supply tube 36 may be pre-closed.

A boiler 31, compressor 32, mixer 33, and exhaust device 38 are installed near the entrance of the starting-side vertical hole VH1 shown in Figure 4. The boiler 31 discharges superheated steam, for example, heated to above 100°C. The steam discharged from the boiler 31 may be saturated steam. The compressor 32 compresses and discharges outside air. The superheated steam discharged from the boiler 31 and the outside air discharged from the compressor 32 are both supplied to the mixer 33 and mixed. Hereinafter, the mixture of superheated steam and outside air mixed in the mixer 33 and discharged is referred to as heating steam. A steam valve 311 is provided in the piping connecting the boiler 31 and the mixer 33, and an air valve 321 is provided in the piping connecting the compressor 32 and the mixer 33. By adjusting the throttle amount by operating the steam valve 311 and air valve 321, it is possible to adjust the temperature and flow rate of the heating steam sent out from the mixing device 33. The exhaust device 38 has a muffling section 381 and an exhaust duct 382.

A supply hose SH extends from the mixing device 33. This supply hose SH is connected to the steam supply port 3411 of the plug member 341. An exhaust hose CH extends from the steam exhaust port 3412 of the plug member 341. This exhaust hose CH is connected to the silencer 381. An exhaust valve CH1 is provided midway along the exhaust hose CH to adjust the flow rate of fluid flowing through the exhaust hose CH. In the above-mentioned lining pipe diameter expansion process (step S50), this exhaust valve CH1 and steam valve 311 are closed, the air valve 321 is open, and the compressor 32 is operated to supply outside air (air) into the inside of the lining pipe LP.

In the lining pipe heating process (step S60), heating steam (e.g., steam at 80°C to 100°C) is used. Heating steam is blown into the expanded lining pipe LP from slit holes 361 and round holes 362 in the steam supply tube 36. The lining pipe LP is kept pressed against the inner surface of the existing pipe EPL and is heated by the heating steam. As a result, the thermosetting resin impregnated in the lining pipe LP begins to harden.

A drain discharge pipe 37 is inserted into the end of the lining pipe LP on the arrival side. In Figure 4, for convenience of illustration, the drain discharge pipe 37 is shown as being inserted into the upper part of the lining pipe LP, but in reality, the drain discharge pipe 37 is inserted into the lower end part of the lining pipe LP. The heating steam loses a certain amount of heat to the lining pipe LP, and some of it turns into drain inside the lining pipe LP. A pipe equipped with a valve 371 is connected to the drain discharge pipe 37. By opening this valve 371, the drain generated inside the lining pipe LP is discharged outside the lining pipe LP.

The heating steam supplied from the steam supply tube 36 on the arrival side of the lining pipe LP flows through the lining pipe LP toward the steam outlet 3412 in the plug member 341 on the departure side, gradually decreasing in temperature. It then passes from the steam outlet 3412 through the exhaust hose CH and into the muffling section 381. The muffling section 381 has an internal space with a cross-sectional area larger than that of the exhaust hose CH and is also equipped with sound-absorbing material. The heating steam carries sound waves such as the cooking noise of the boiler 31, and also generates noise emitted into the atmosphere. The muffling section 381 muffles these sounds. The heating steam that has passed through the muffling section 381 is exhausted into the atmosphere through the exhaust duct 382.

In step S60, the temperature of the lining pipe LP itself is measured at both the arrival end and departure end of the lining pipe LP. The temperature at each end of the lining pipe LP rises initially due to heat generated by the curing of the thermosetting resin, but then begins to decrease. When the temperature of the lining pipe LP changes from rising to decreasing and settles at an approximately constant temperature, the thermosetting resin has cured to a sufficient level. From this state, heating steam with a higher temperature (e.g., 100°C to 105°C) than the heating steam required to complete the curing is supplied. This increases the strength of the thermosetting resin. The heating time required for increasing strength using heating steam is determined in advance through experimentation, and step S60 ends when that heating time has elapsed.

According to the lining pipe heating process (step S60) described above, while the lining pipe LP is pressed against the inner surface of the existing pipe EPL, the impregnated thermosetting resin hardens and increases in strength, forming a new self-supporting pipeline made of the lining pipe LP inside the inner surface of the existing pipe EPL. The existing pipe EPL is an example of an outer pipe, and the lining pipe LP, formed as a new self-supporting pipeline, is an example of an inner pipe.

Then, the boiler 31 is stopped and the steam valve 311 is closed, supplying outside air (room temperature air) instead of the heating steam to cool the hardened lining pipe LP.

In step S70 shown in Figure 3, the pipe opening is cut to open both ends of the lining pipe LP. The lining pipe LP shown in Figure 4 protrudes from the existing pipe EPL on both the starting and destination sides. In step S70, the protruding portions on both ends of the hardened lining pipe LP are cut so that the ends of the lining pipe LP coincide with the ends of the existing pipe EPL. As a result, the lining pipe LP is completed, lining the inner surface of the existing pipe EPL, which was buried and used as an internal pressure pipe, and whose pipe ends roughly coincide with those of the existing pipe EPL. Steps S40 to S70 correspond to an example of a lining pipe formation process.

Next, the pipe end member installation process (step S80) is carried out.

Figure 3(b) is a flowchart showing in detail the tube end member installation process (step S80) shown in Figure 3(a). Figure 5 is a cross-sectional view showing the installation of the tube end member of this embodiment. In Figure 5, as with Figure 1, the left side of the figure is the tube end side, and the right side of the figure is the rear side.

The pipe end member 10 has a packing member 11 and an expansion band 12. In the installation process, the packing member 11 is first installed (step S81).

Figure 5(a) shows only the upper portion of the cross section of the lining pipe LP, the end of which was cut in step S70, and the existing pipe EPL. The thickness of the wall of the existing pipe EPL varies depending on the diameter of the existing pipe, but is, for example, 5 mm or more and 10 mm or less. The thickness of the wall of the lining pipe LP also varies depending on the diameter of the existing pipe, but is, for example, 10 mm or more and 20 mm or less.

In addition, Figure 5(a) shows only the upper portion of the cross section of the packing member 11 of this embodiment, below the double pipe WP consisting of the lining pipe LP (corresponding to the inner pipe) and the existing pipe EPL (corresponding to the outer pipe). This double pipe WP is an example of a double-structure pipe. The thickness of the packing member 11 is approximately 5 mm, but Figure 5 ignores the relative relationship between the thicknesses of each member. The packing member 11 shown in Figure 5(a) is made of rubber and is extensible and flexible. The packing member 11 has a cylindrical portion 110 and a flange portion 111. The cylindrical portion 110 and the flange portion 111 are molded integrally.

Figure 5(b1) shows the packing member 11 attached with adhesive from the existing pipe thickness surface EPL2 (the outer pipe thickness surface) and the lining pipe thickness surface LP2 (the inner pipe thickness surface) to the entire end circumference of the inner circumferential surface LPi of the lining pipe LP. The existing pipe thickness surface EPL2 is the surface between the inner circumferential surface EPLi and the outer circumferential surface EPLo at the end EPL1 of the existing pipe EPL. The lining pipe thickness surface LP2 is the surface between the inner circumferential surface LPi and the outer circumferential surface LPo at the end LP1 of the lining pipe LP. The flange portion 111 of the packing member 11 is hollow and disk-shaped, extending across both the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, and covering the area between the end EPL1 of the existing pipe EPL and the end LP1 of the lining pipe LP. The flange portion 111 is attached to the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. By being attached to the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, the effectiveness of preventing water from infiltrating into the small gap between the pipe end EPL1 of the existing pipe EPL and the pipe end LP1 of the lining pipe LP is enhanced. Furthermore, the flange portion 111 acts as a locking portion that locks to the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2 when a force moving inward is applied to the packing member 11. When the flange portion 111 acts as a locking portion, the locking force can be increased by having the flange portion 111 attached to the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. However, the flange portion 111 does not have to be attached to the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. The flange portion 111 is made of the same rubber as the cylindrical portion 110, but the locking force can be increased by making the flange portion 111 less extensible than the cylindrical portion 110 (for example, by making it contain a rigid body).

The cylindrical portion 110 is formed contiguous with the flange portion 111 and covers the entire circumference of the end of the inner circumferential surface LPi of the lining pipe LP. As shown in FIG. 5(b1), this cylindrical portion 110 is attached to the entire circumference of the end of the inner circumferential surface LPi of the lining pipe LP. When attaching the packing member 11, adhesive may be applied to the packing member 11, or adhesive may be applied to the existing pipe thickness surface EPL2, the lining pipe thickness surface LP2, and the inner circumferential surface LPi of the lining pipe LP and then the packing member 11 may be attached. Alternatively, adhesive may be applied to both of these surfaces and then the packing member 11 may be attached to the existing pipe thickness surface EPL2, the lining pipe thickness surface LP2, and the inner circumferential surface LPi of the lining pipe LP.

The flange portion 111 shown in Figure 5(b1) bends outward at the edge of the inner surface LPi of the lining pipe LP and extends the total thickness of the lining pipe thickness surface LP2 and the existing pipe thickness surface EPL2. Therefore, the bent tip 1111 of the flange portion 111 coincides with the outer surface EPLo of the existing pipe EPL. While it is sufficient for the flange portion 111 to extend outward from the lining pipe thickness surface LP2, extending it beyond the total thickness of the lining pipe thickness surface LP2 and the existing pipe thickness surface EPL2 can enhance the effectiveness of preventing water from entering between the pipe end EPL1 of the existing pipe EPL and the pipe end LP1 of the lining pipe LP. Note that "outside" refers to the radially outward side when the central axis of the existing pipe EPL is considered the inside.

In the explanation using Figure 5(b1), the packing member installation process was described for the case in which the protruding portion of the end of the lining pipe LP was cut in step S70 so that the position of the end of the lining pipe LP and the position of the end of the existing pipe EPL were aligned. However, in reality, when the protruding portion of the end of the lining pipe LP is cut, the position of the pipe end LP1 of the lining pipe LP and the position of the pipe end LP1 of the existing pipe EPL may be slightly misaligned. However, even if there is a misalignment, the amount of protrusion of the end of the lining pipe LP from the end of the existing pipe EPL is only a few millimeters.

When there is a misalignment between the end of the lining pipe LP and the end of the existing pipe EPL, a method for dealing with the misalignment is explained using Figure 5 (b2). When there is a misalignment, the misaligned portion is filled with caulking material CA before or after the packing member 11 is attached. This caulking material CA is an example of a water-stopping material. Note that an adhesive with a water-stopping effect may be used instead of caulking material CA. In that case, the adhesive is an example of a water-stopping material. Even when filled with this caulking material CA, the flange portion 111 of the packing member 11 extends across both the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. In other words, the concept of the flange portion 111 extending across both the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2 also includes cases where small amounts of inclusions such as caulking material or adhesive exist between the flange portion 111 and the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2.

In the pipe end member installation process (step S80) shown in Figure 3, once the packing member 11 is installed at the ends of the existing pipe EPL and the lining pipe LP, the expansion band 12 is fitted (step S82).

Like the expansion band 932 described with reference to FIG. 1, the expansion band 12 of this embodiment is C-shaped and made of stainless steel. This expansion band 12 is an example of a pressing member. In FIG. 5(c), the expansion band 12 is fitted from the inside onto the cylindrical portion 110 of the packing member 11. To fit the expansion band 12 from the inside, the C-shaped expansion band 12 is expanded using an expansion tool (not shown), and a fixing plate (not shown) is inserted into the C-shaped gap to close the gap. By inserting the fixing plate, the expansion band 12 remains expanded even after the expansion tool is removed, and presses the cylindrical portion 110 of the packing member 11 outward. The fixing plate that closes the C-shaped gap is inserted while being struck with a hammer from the pipe end toward the back. The expansion band 12 is expanded using an expansion tool (not shown), but is further expanded by inserting the fixing plate. Even if the fixing plate is struck with a hammer, the packing member 11 of this embodiment is prevented from shifting backward because the flange portion 111 is engaged with the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. Multiple expansion bands 12 may be fitted into the cylindrical portion 110. In this way, the cylindrical portion 110 of the packing member 11 is pressed against the entire end of the inner surface LPi of the lining pipe LP. The pipe end member 10 is then positioned at the ends of the existing pipe EPL and the lining pipe LP.

Figure 5(c) shows the state when the expansion band 12 is fitted and the installation process of the pipe end member 10 is completed. The packing member 11 shown in Figure 5(c) has the flange portion 111 engaged with the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, and the existing pipe thickness surface EPL2, the lining pipe thickness surface LP2, and the small gap between them are also covered by the flange portion 111. However, the outer diameter of the flange portion 111 may be slightly smaller to cover the lining pipe thickness surface LP2, the small gap, and the inner portion of the existing pipe thickness surface EPL2, while leaving the outer portion of the existing pipe thickness surface EPL2 exposed. Furthermore, the entire circumference of the end of the inner surface LPi of the lining pipe LP is covered by the cylindrical portion 110, with no exposed portion.

The cylindrical portion 110 may have a highly cylindrical shape with a constant diameter along its entire length in the axial direction (extension direction), or it may have a truncated cone shape with a slightly smaller diameter toward the back. The latter cylindrical portion 110 makes it easier to insert the packing member 11 into the inside of the lining pipe LP. The cylindrical portion 110 may also have a combination of parts with a constant diameter and parts with a gradually decreasing diameter, so that the diameter is smaller toward the back than toward the pipe end (near side) when viewed as a whole.

In Figure 2, a lining pipe LP is installed on the inner surface of the cut-out existing pipe EPL, as shown by the dotted line. Pipe end members 10 are installed at each end of the double pipe WP consisting of the lining pipe LP and the existing pipe EPL using the pipe end member installation process described using Figure 3(b), but are not shown in Figure 2.

In the pipe structure construction method shown in Figure 3(a), a process (step S90) is carried out to connect the double pipe WP on which the pipe end member 10 is installed to the new pipe NP.

In step S90, coupling members 20 (see FIG. 6(c)) are installed at both ends of the double pipe WP on which the pipe end members 10 are installed. A coupling member is also installed at the downstream end of the upstream new pipe NP1, which was dug up by excavating the starting-side vertical hole VH1 shown in FIG. 2. A coupling member is also installed at the upstream end of the downstream new pipe NP2, which was dug up by excavating the destination-side vertical hole VH2. Next, a cast iron upstream connecting pipe CP1 (see FIG. 2) is installed between the starting-side coupling member of the double pipe WP and the coupling member installed at the downstream end of the upstream new pipe NP1. A cast iron downstream connecting pipe CP2 (see FIG. 2) is also installed between the destination-side coupling member of the double pipe WP and the coupling member installed at the upstream end of the downstream new pipe NP2. Once the process of connecting the double pipe WP and the new pipe NP (step S90) is complete, the pipe structure PS shown in Figure 2 is constructed, connecting the upstream new pipe NP1, upstream connecting pipe CP1, double pipe WP, downstream connecting pipe CP2, and downstream new pipe NP2. Once the pipe structure PS is constructed, the starting vertical hole VH1 and the arrival vertical hole VH2 are filled in, and the narrow road R2 is paved.

Figure 6 is a cross-sectional view showing how a coupling member is installed on the outer surface of a double pipe. In this figure, the left side is the pipe end side and the right side is the rear side.

As shown in Figure 6(a), an outer peripheral rib EPL3 that protrudes outward extends circumferentially on the outer peripheral surface EPLo of the existing pipe EPL.

As shown in Figure 6(b), in the installation process of the coupling member 20, a half-split fixing flange FR1 is first attached to the rear side of the outer peripheral rib EPL3 provided on the outer peripheral surface EPLo of the existing pipe EPL. The half-split fixing flange FR1 is a flange divided into half arcs so as to sandwich the outer peripheral surface EPLo of the existing pipe EPL from the outside. Furthermore, a loose flange FR2 is fitted onto the pipe end EPL1 side of the outer peripheral surface EPLo of the existing pipe EPL. A threaded rod 26 is then passed through the through holes formed in the loose flange FR2 and the half-split fixing flange FR1. Prior to passing the threaded rod 26, a nut 272 is attached between the loose flange FR2 and the half-split fixing flange FR1. Multiple threaded rods 26 are arranged circumferentially spaced around the entire circumference of each flange. After the threaded rod 26 is passed through the through-hole, a nut 273 is attached to the rear side of the half-split fixed flange FR1. Two O-rings 25 are then fitted onto the outer surface EPLo of the existing pipe EPL, toward the end of the loose flange FR2. If the flange portion 111 has a portion that protrudes outward beyond the outer surface EPLo of the existing pipe EPL and this protruding portion interferes with the fitting of the loose flange FR2, O-ring 25, or coupling member 20 (described below), this portion may be removed as appropriate.

Then, the coupling member 20 is attached. Figure 6(c) shows the coupling member 20 attached to the outer surface EPLo of the existing pipe EPL.

To install the coupling member 20, first, the coupling member 20 is fitted onto the outer circumferential surface EPLo of the existing pipe EPL so that the coupling member 20 faces the loose flange FR2 with two O-rings 25 sandwiched between them. The coupling member 20 is a cylindrical cast iron member with a first flange 21 at one end and a second flange 22 at the other end. The coupling member 20 also has an annular protrusion 24 that protrudes inward from its inner circumferential surface 20i. Furthermore, a stepped portion 23 is formed circumferentially on the inner circumferential surface 20i of the coupling member 20, closer to the pipe end than the annular protrusion 24, to receive the tip of a connecting pipe, such as the upstream connecting pipe CP1 or downstream connecting pipe CP2 shown in Figure 2. This connecting pipe is an example of a separate pipe. The coupling member 20 is used to connect the end of the existing pipe EPL to the end of a connecting pipe.

Once the coupling member 20 is fitted onto the outer periphery EPLo, the threaded rod 26, which passes through the loose flange FR2 and the half-split fixed flange FR1, is also passed through the through-hole formed in the first flange 21. A nut 271 is then attached to the pipe end side of the first flange 21. The coupling member 20 is then pushed toward the rear by tightening the nut 271, installing the coupling member 20 in the double-walled pipe WP. As the nut 271 is tightened, the annular protrusion 24 presses and compresses the flange portion 111 of the packing member 11 against the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2. The first flange 21 also presses and compresses the two O-rings 25 against the loose flange FR2. Once these are compressed, installation of the coupling member 20 is complete. If the flange portion 111 starts to press first and the O-ring 25 cannot be pressed, simply turn the nut 272 to move the loose flange FR2 toward the pipe end and compress the O-ring 25. Conversely, if the O-ring 25 starts to press first and the flange portion 111 cannot be pressed, simply turn the nut 272 to move the loose flange FR2 toward the back and then tighten the nut 271 again.

The tip of the connecting pipe abuts against a step 23 formed on the inner surface 20i of the coupling member 20. The connecting pipe is then connected to the coupling member 20 by connecting the second flange 22 of the coupling member 20 to the flange on the outer surface of the connecting pipe.

The pipe end member 10 and pipe structure PS described above allow the pipe end member 10 to be installed without scraping or stripping off the pipe end LP1 side portion of the lining pipe LP, making installation of the pipe end member 10 easy and efficient. Furthermore, the flange portion 111 seals the small gap between the pipe end EPL1 of the existing pipe EPL and the pipe end LP1 of the lining pipe LP, preventing pressurized fluid flowing through the lining pipe L from entering the gap. Furthermore, because the cylindrical portion 110 of the packing member 11 only needs to be pressed against the lining pipe LP and not against the existing pipe EPL, only one or two expansion bands 12 are required. This reduces the parts cost of the pipe end member 10 and the labor required to install the expansion bands 12. Furthermore, by inserting the cylindrical portion 110 into the inner circumferential surface LPi of the lining pipe LP, the flange portion 111 can be positioned to extend across both the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, making it easy to install the pipe end member 10 in its predetermined position. Furthermore, since the entire circumference of the end of the inner circumferential surface LPi of the lining pipe LP is covered by the cylindrical portion 110, pressure fluid is less likely to enter between the flange portion 111 and the lining pipe thickness surface LP2, improving the sealing performance of the pipe end member 10. Furthermore, by fitting the expansion band 12 into the cylindrical portion 110, pressure fluid is less likely to enter between the inner circumferential surface LPi of the lining pipe LP and the cylindrical portion 110 toward the lining pipe thickness surface LP2, improving the sealing performance of the pipe end member 10. Furthermore, the expansion band 12 firmly secures the packing member 11 to the double pipe WP. In addition, the annular protrusion 24 of the coupling member 20 presses the flange portion 111 of the packing member 11 against the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, improving the sealing performance of the pipe end member 10 in the pipe structure PS.

As mentioned above, in the conventional pipe end member 93 shown in FIG. 1, as the expansion band 932 is fitted, the packing member 931 shifts toward the rear. If the outer pipe 91 is made of iron, such as cast iron, rust on the exposed end of the inner circumferential surface 91i may contaminate the pressurized fluid, causing problems when the pressurized fluid is used. Even if the outer pipe 91 is not made of iron, if it is aged or damaged, a portion of the exposed pipe wall may peel off and contaminate the pressurized fluid, which may also cause problems when the pressurized fluid is used. In contrast, with the pipe end member 10 and pipe structure PS of this embodiment, even if a force is applied to shift the cylindrical portion 110 toward the rear, the flange portion 111 engages with the existing pipe thickness surface EPL2 and the lining pipe thickness surface LP2, preventing it from shifting toward the rear. This prevents the end of the inner circumferential surface EPLi of the existing pipe EPL from being exposed. Also, as mentioned above, fewer expansion bands 12 are required, so the force that tends to shift the cylindrical portion 110 toward the rear when installing the pipe end member 93 is also reduced, making the pipe end member 93 less likely to shift. Furthermore, even if the pipe end member 93 does shift toward the rear, the inner surface EPLi of the existing pipe EPL is covered all the way to the end by the lining pipe LP, so there is no risk of rust or debris from the existing pipe EPL being mixed into the pressurized fluid.

Next, we will explain a modified example of this embodiment. In the following explanation, components with the same names as components explained so far will be assigned the same reference numerals as used so far, and duplicate explanations may be omitted.

Figure 7(a) is a cross-sectional view similar to Figure 6(c) showing a first modified example of the pipe end member and pipe structure. Note that in Figure 7 and Figure 8, which will be described later, only a portion of the pipe structure PS is shown.

As shown in Figure 7(a), the pipe end member 10 and pipe structure PS of this first modified example differ from the previous embodiment shown in Figures 2 to 6 in that they do not have a cylindrical portion 110. In other words, the packing member 11 of this first modified example is composed only of a flange portion 111.

This first variant also achieves the same effects as the pipe end member 10 and pipe structure PS in the previous embodiment. The packing member 11 can also be constructed inexpensively. Furthermore, because the expansion band 12 is not used, the component costs of the pipe end member 10 and the labor required to install the expansion band 12 can be reduced. However, the sealing performance and durability of the pipe end member 10 in the pipe structure PS are higher in the previous embodiment.

Figure 7(b) is a cross-sectional view similar to Figure 6(c) showing a second modified example of the tubular structure.

As shown in Figure 7(b), the tubular structure PS of this second modified example differs from the previous embodiment in that the loose flange FR2 and O-ring 25 are omitted.

This second variant also achieves the same effects as the pipe end member 10 and pipe structure PS in the previous embodiment. Furthermore, by omitting the loose flange FR2 and O-ring 25, the cost of these parts and the installation labor required can be reduced. However, the previous embodiment, which includes the O-ring 25, provides better sealing against pressurized water. Furthermore, sealing performance can be improved by forming an annular recess on the inner circumferential surface 20i of the coupling member 20, fitting an O-ring into the annular recess, and attaching the coupling member 20 to the double pipe WP.

Figure 8(a) is a cross-sectional view similar to Figure 6(c) showing a third modified example of the tubular structure.

As shown in Figure 8(a), the pipe structure PS of this third modified example differs from the previous embodiment in that the protruding length of the annular protrusion 24 is short. The annular protrusion 24 of the third modified example has a protruding length that is approximately the same as or slightly shorter than the thickness of the existing pipe EPL. As a result, the flange portion 111 is pressed by the annular protrusion 24 against the existing pipe thickness surface EPL2 (see Figure 5(a)), and not against the lining pipe thickness surface LP2 (see Figure 5(a)).

This third variant also achieves the same effects as the pipe end member 10 and pipe structure PS in the previous embodiment.

Figure 8(b) is a cross-sectional view similar to Figure 6(c) showing a fourth modified example of the tubular structure.

As shown in Figure 8(b), the pipe structure PS of this fourth modified example differs from the previous embodiment in that the annular protrusion 24 is formed with an L-shaped cross section. The protruding end of the annular protrusion 24 of the fourth modified example has a protruding portion 241 that protrudes toward the back and has a thin thickness that is approximately the same as or slightly shorter than the thickness of the lining pipe LP. This protruding portion 241 is located opposite the lining pipe thickness surface LP2 (see Figure 5(a)). Therefore, the flange portion 111 is pressed against the lining pipe thickness surface LP2 by the protruding portion 241 of the annular protrusion 24, and is not pressed against the existing pipe thickness surface EPL2 (see Figure 5(a)).

This fourth variant also achieves the same effects as the pipe end member 10 and pipe structure PS in the previous embodiment.

The present invention is not limited to the embodiments and modifications described above, and various modifications can be made within the scope of the claims. For example, the pipe end member 10 can be used not only for double-walled pipes in which the outer pipe is an existing pipe and the inner pipe is a lined pipe, but also for double-walled pipes in which a new outer pipe is used and a new inner pipe, whether or not it is lined. As one example, the pipe end member 10 may be used to seal small gaps that may occur between the outer and inner pipes of a double-walled pipe in which the outer pipe is used to ensure rigidity and the inner pipe is made of a material that is not corroded by pressure fluid. Furthermore, if sufficient adhesive strength can be obtained between the flange portion 111 and the lining pipe thickness surface LP2 or the existing pipe thickness surface EPL2 using an adhesive or the like, the annular protrusion 24 may be omitted. In addition, if sufficient adhesive strength can be obtained between the cylindrical portion 110 and the inner circumferential surface LPi of the lining pipe LP using an adhesive or the like, the expansion band 12 may be omitted.

Furthermore, even if a component is included only in the description of the embodiment or the description of the variation described above, that component may also be applied to the embodiment or other variation.

10 Pipe end member 11 Packing member 110 Cylindrical portion 111 Flange portion 12 Expansion band 20 Joint member 24 Annular protrusion EPL Existing pipe (outer pipe)
EPLi: Inner surface EPLo: Outer surface EPL2: Existing pipe thickness surface LP: Lining pipe (inner pipe)
LPi Inner surface LPo Outer surface LP2 Lining pipe thickness surface WP Double pipe PS Pipe structure

Claims (3)

A pipe end member to be installed at the end of a double-structure pipe having an outer pipe and an inner pipe,
a hollow disk-shaped flange portion extending across both an outer pipe thickness surface between the outer peripheral surface and the inner peripheral surface at the pipe end of the outer pipe and an inner pipe thickness surface between the inner peripheral surface and the outer peripheral surface at the pipe end of the inner pipe;
a cylindrical portion formed continuously with the flange portion and covering the entire circumference of an end portion of an inner circumferential surface of the inner pipe;
a pressing member that presses the cylindrical portion toward an inner circumferential surface of the inner tube ;
a fixing plate that increases the pressing force of the pressing member toward the inner circumferential surface of the inner tube while pressing the pressing member toward the inner side of the inner tube . Existing buried pipes and
a lining pipe lining the inner circumferential surface of the existing pipe;
a pipe end member disposed at an end of the lining pipe,
a cylindrical portion formed contiguous with the flange portion and covering the entire end circumference of the inner peripheral surface of the lining pipe; a pressing member that presses the cylindrical portion toward the inner peripheral surface of the lining pipe; and a fixing plate that increases the pressing force of the pressing member toward the inner peripheral surface of the lining pipe while pressing the pressing member toward the inner peripheral surface of the lining pipe . A cylindrical joint member is provided to connect the end of the existing pipe and the end of the separate pipe,
the coupling member has an annular protrusion that protrudes annularly inward from an inner circumferential surface of the coupling member,
3. The pipe structure according to claim 2, wherein the flange portion is pressed against at least one of the thickness surface of the existing pipe and the thickness surface of the lining pipe by the annular protrusion.