Extendable joint device

Abstract

To protect a rubber ring by preventing the rubber ring from swelling, when a water leakage is generated between a first pipe and a second pipe.SOLUTION: An extendable joint device 10 connecting a first pipe 1 and a second pipe 2 includes an inner extendable joint device 20, and an outer extendable joint device 40 provided outside the inner extendable joint device 20. The outer extendable joint device 40 has a rubber ring 41, and a cylindrical cover 50 provided radially outside the rubber ring 41.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an expansion joint device that connects a first pipe and a second pipe and has a rubber ring, and in particular to an expansion joint device that can prevent expansion of the rubber ring and protect the rubber ring. [Background technology]

[0002] BACKGROUND ART Expansion joint devices that connect first and second pipes and have rubber rings have been known.

[0003] Such an expansion joint device has a rubber ring and is installed between a first pipe and a second pipe that transport various fluids such as cooling water and wastewater.

[0004] Incidentally, the expansion joint device is attached between the first pipe and the second pipe as described above, and has a rubber ring disposed between the first pipe and the second pipe.

[0005] In such an expansion joint device, if a water leak occurs between the first and second pipes, the rubber ring may bulge significantly outward in the radial direction, which could lead to the rubber ring coming into contact with an external obstacle and being damaged. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 3-285137 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-91215 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-53317 [Patent Document 4] Japanese Patent Application Laid-Open No. 2004-10355 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] The present disclosure has been made in consideration of these points, and aims to provide an expansion joint device that can prevent the expansion of a rubber ring and protect the rubber ring even if a leak occurs between the first pipe and the second pipe. [Means for solving the problem]

[0008] The present disclosure relates to an expansion joint device that connects a cylindrical first pipe having a first pipe flange and a cylindrical second pipe having a second pipe flange, the expansion joint device comprising: an inner expansion joint connected to the first pipe flange and the second pipe flange; and an outer expansion joint arranged radially outward of the inner expansion joint, wherein the inner expansion joint has a first connection flange connected to the first pipe flange, a second connection flange connected to the second pipe flange, and a cylindrical body extending between the first connection flange and the second connection flange, and the outer expansion joint is arranged between the first connection flange and the second connection flange and has a rubber ring extending in the circumferential direction, and a cylindrical cover attached radially outward of the rubber ring to cover the rubber ring from the outside.

[0009] The present disclosure provides an expansion joint device, wherein when the expansion joint device is viewed in a cross section parallel to an axis, the rubber ring has a wave-shaped portion.

[0010] The present disclosure relates to an expansion joint device in which, when the expansion joint device is viewed in a cross section parallel to the axis, the cylindrical cover is parallel to the axis and has a shape that covers the rubber ring from the outside.

[0011] The present disclosure is an expansion joint device, wherein the cylindrical cover has a plurality of cylindrical cover portions that can be separated in the axial direction.

[0012] Disclosed is an expansion joint device in which a first cylindrical cover portion is radially movable relative to an adjacent second cylindrical cover portion.

[0013] The present disclosure is an expansion joint device, wherein a first mounting flange of the first cylindrical cover portion is joined to a second mounting flange of the second cylindrical cover portion, mounting bolts are inserted into bolt holes of the first mounting flange and bolt holes of the second mounting flange, and inner diameters of the bolt holes of the first mounting bolt and the bolt holes of the second mounting bolt are larger than outer diameters of the mounting bolts. [Effects of the Invention]

[0014] As described above, according to the present disclosure, when water leakage occurs between the first pipe and the second pipe, it is possible to prevent the rubber ring from expanding and to protect the rubber ring. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a side cross-sectional view of an embodiment of an expansion joint device taken along a cross section parallel to an axis, emphasizing the outer expansion joint. [Figure 2] FIG. 2 is a cross-sectional side view taken along a different cross section from FIG. 1, emphasizing the outer expansion joint. [Figure 3] FIG. 3 is a diagram showing the assembly operation of the expansion joint device, emphasizing the outer expansion joint. [Figure 4] Figure 4 shows the expansion joint device viewed from the axial direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Embodiments of the present invention> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0017] 1 to 4 are views showing an embodiment of the present invention, of which Figs. 1 and 2 are cross-sectional views of an expansion joint device taken along a cross section parallel to the axis, with the outer expansion joint emphasized, Fig. 3 is a view showing the operation of the expansion joint device, with the outer expansion joint emphasized, and Fig. 4 is a cross-sectional view of the expansion joint device taken along a cross section perpendicular to the axis.

[0018] As shown in Figures 1 to 3, the expansion joint device 10 connects a cylindrical first pipe 1 having a first pipe flange 1A and a cylindrical second pipe 2 having a second pipe flange 2A in a manner that allows them to expand and contract.

[0019] Such an expansion joint device 10 comprises an inner expansion joint 20 connected to the first pipe flange 1A of the first pipe 1 and the second pipe flange 2A of the second pipe 2, and an outer expansion joint 40 connected to the first pipe flange 1A and the second pipe flange 2A. A sealed space 10A is formed between the inner expansion joint 20 and the outer expansion joint 40.

[0020] Furthermore, a first connection flange 21 and a second connection flange 22 are fixed to the first pipe flange 1A of the first pipe 1 and the second pipe flange 2A of the second pipe 2 by bolts 21A and 22A, respectively. In this case, the outer ends of the bolts 21A and 22A are tightened by nuts 21B and 22B, respectively. The first connection flange 21 and the second connection flange 22 constitute an inner expansion joint 20, as will be described later.

[0021] Next, we will describe the inner expansion joint 20. As described above, the inner expansion joint 20 has the first connection flange 21 connected to the first piping flange 1A, and the second connection flange 22 connected to the second piping flange 2A. The first connection flange 21 is provided with a cylindrical extension part 24 on its radially inward side, extending in the direction of the axis C (see Figure 4) (hereinafter also referred to as the axial direction).

[0022] A cylindrical pipe 25 extends between the first connection flange 21 and the second connection flange 22. In this case, a flange 25a is provided on the cylindrical pipe 25 on the side of the second connection flange 22, and this flange 25a extends between the second piping flange 2A and the second connection flange 22. A first seal member 25b is attached to the flange 25a and is disposed between the flange 25a and the second connection flange 22.

[0023] In this embodiment, a gap 29 is formed radially inward of the second connection flange 22, and the flange 25a of the cylindrical pipe 25 is inserted into this gap 29. Therefore, the flange 25a of the cylindrical pipe 25 is fixed along the axial direction by the second piping flange 2A and the second connection flange 22.

[0024] On the other hand, since a gap 29 is formed along the radial direction on the radially inner side of the second connection flange 22, the cylindrical pipe 25 is movable in the radial direction relative to the second connection flange 22.

[0025] Therefore, even if a radial misalignment occurs between the first pipe 1 and the second pipe 2, the cylindrical pipe 25 can move radially relative to the second connection flange 22, thereby effectively absorbing this radial misalignment.

[0026] A second sealant 37 is interposed between the second connection flange 22 side end 24a of the cylindrical extension 24 of the second connection flange 22 and the cylindrical tube 25, and this second sealant 37 is held by a holder 32 attached to the cylindrical extension 24 with a mounting bolt 34. The mounting bolt 34 is tightened with a nut 35, and a lock nut 36 is further attached to the mounting bolt 34.

[0027] In this case, the cylindrical pipe 25 is able to move axially along the cylindrical extension 24 of the first connection flange 21, so that if an axial misalignment occurs between the first pipe 1 and the second pipe 2, the cylindrical pipe 25 can move axially along the cylindrical extension 24 of the first connection flange 21, thereby effectively absorbing this axial misalignment.

[0028] The first connection flange 21 is provided with a third seal member 21b that abuts against the first piping flange 1A.

[0029] Next, we will describe the outer expansion joint 40. The outer expansion joint 40 is provided between the first connection flange 21 and the second connection flange 22, and has a rubber ring 41 that extends in the circumferential direction, and a cylindrical cover 50 that is attached radially outward of the rubber ring 41, covers the rubber ring 41 from the outside, and extends in the circumferential direction.

[0030] Of these, the rubber ring 41 is made of chloroprene (polychloroprene) rubber. The rubber ring 41 is wrapped cylindrically around the outside of the first connection flange 21 and the second connection flange 22 in a strip-like state, and is attached to the outer peripheries of the first connection flange 21 and the second connection flange 22 in the circumferential direction by butting together both ends of the strip-shaped rubber ring 41 and bonding them together. In this case, both ends of the rubber ring 41 are joined to each other by vulcanization bonding. Alternatively, both ends of the rubber ring 41 may be bonded using an instant adhesive.

[0031] 1 to 3, when the expansion joint device 10 is viewed in a cross section parallel to the axis C (see FIG. 4), the rubber ring 41 has a corrugated portion 41A extending between the first connection flange 21 and the second connection flange 22, and a pair of fixing portions 42 provided on both axial ends of the corrugated portion 41A. The rubber ring 41 prevents the liquid in the sealed space 10A from leaking outward.

[0032] Of these, when water leaks from the inner expansion joint 20 arranged between the first pipe 1 and the second pipe 2 and the leaked liquid flows into the sealed space 10A, the corrugated portion 41A expands radially outward to absorb the pressure of the leaked liquid.

[0033] Furthermore, the fixing portion 42 is a portion that is fixed to the outer periphery of the first connection flange 21 and the outer periphery of the second connection flange 22. In this embodiment, the protruding pieces 42a of the fixing portion 42 engage with the protrusions 21a provided on the outer periphery of the first connection flange 21 and the protrusions 22a provided on the outer periphery of the second connection flange 22, respectively. This allows the fixing portion 42 of the rubber ring 41 to be fixed to the outer periphery of the first connection flange 21 and the outer periphery of the second connection flange 22.

[0034] The cylindrical cover 50 is made entirely of steel, and has a shape parallel to the axis C when the expansion joint device 10 is viewed in a cross section parallel to the axis C.

[0035] Specifically, the cylindrical cover 50 has ten divided portions 50A, 50A divided along the circumferential direction (see FIG. 4). As shown in FIG. 4, the divided portions 50A, 50A divided along the circumferential direction have joining flanges 61, 61 provided on both ends in the circumferential direction. The divided portions 50A and the circumferentially adjacent divided portions 50A are fixed to each other by joining the joining flanges 61, 61, inserting mounting bolts 62 into the joining flanges 61, 61, and tightening the mounting bolts 62 with tightening nuts 63.

[0036] The divided portions 50A of the cylindrical cover 50 have the same shape.

[0037] 1 to 3, the divided portion 50A of the cylindrical cover 50 has a plurality of, for example, three cylindrical cover portions 51, 52, and 53 that can be divided along the direction of the axis C (see FIG. 4). When the expansion joint device 10 is viewed in a cross section parallel to the axis C (see FIG. 1), these three cylindrical cover portions 51, 52, and 53 all have a shape parallel to the axis C and cover the rubber ring 41 from the radially outer side. Also, in FIG. 1, the three cylindrical cover portions 51, 52, and 53 are arranged in a straight line along the axis C.

[0038] Of these, the first cylindrical cover portion 51 is movable in the radial direction relative to the second cylindrical cover portion 52 , and the second cylindrical cover portion 52 is movable in the radial direction relative to the third cylindrical cover portion 53 .

[0039] In addition, an attachment flange 51a is attached to the axial end of the first cylindrical cover portion 51 on the side of the second cylindrical cover portion 52, and an end plate 51c is attached to the axial end of the first cylindrical cover portion 51 on the side of the first connection flange 21.

[0040] Further, the second cylindrical cover portion 52 has mounting flanges 52a attached to the end portion on the first cylindrical cover portion 51 side and the end portion on the third cylindrical cover portion 53 side in the axial direction.

[0041] Furthermore, an attachment flange 53a is attached to the axial end of the third cylindrical cover portion 53 on the second cylindrical cover portion 52 side, and an end plate 53c is attached to the axial end of the third cylindrical cover portion 53 on the second connection flange 22 side.

[0042] Next, the joining relationship between the first cylindrical cover portion 51 and the second cylindrical cover portion 52 will be described. A mounting flange (also referred to as the first mounting flange) 51a of the first cylindrical cover portion 51 and a mounting flange (also referred to as the second mounting flange) 52a of the second cylindrical cover portion 52 are joined together, and mounting bolts 55 are inserted into bolt holes 51b of the mounting flange 51a and bolt holes 52b of the mounting flange 52a via washers 58. The mounting bolts 55 are then tightened with tightening nuts 56 via washers 58, thereby joining and fixing the mounting flanges 51a of the first cylindrical cover portion 51 to the mounting flanges 52a of the second cylindrical cover portion 52.

[0043] In this embodiment, a lock nut 57 is attached to the mounting bolt 55 to prevent the tightening nut 56 from loosening.

[0044] In addition, the inner diameters of bolt holes 51b in mounting flange 51a and bolt holes 52b in mounting flange 52a are larger than the outer diameter of mounting bolt 55 (for example, 1.2 to 2.0 times), which allows first cylindrical cover portion 51 and second cylindrical cover portion 52 to move radially relative to each other.

[0045] Next, the joining relationship between the second cylindrical cover portion 52 and the third cylindrical cover portion 53 will be described.

[0046] An attachment flange 52a (also referred to as the second attachment flange) of the second cylindrical cover portion 52 and an attachment flange 53a (also referred to as the third attachment flange) of the third cylindrical cover portion 53 are joined together, and attachment bolts 55 are inserted into bolt holes 52b of the attachment flange 52a and bolt holes 53b of the attachment flange 53 via washers 58. Then, by tightening the attachment bolts 55 with tightening nuts 56 via washers 58, the attachment flange 52a of the second cylindrical cover portion 52 and the attachment flange 53a of the third cylindrical cover portion 53 are joined and fixed together.

[0047] In this embodiment, a lock nut 57 is attached to the mounting bolt 55 to prevent the tightening nut 56 from loosening.

[0048] In addition, the inner diameters of bolt holes 52b in mounting flange 52a and bolt holes 53b in mounting flange 53a are larger than the outer diameter of mounting bolt 55 (for example, 1.2 to 2.0 times), which allows second cylindrical cover portion 52 and third cylindrical cover portion 53 to move radially relative to each other.

[0049] Next, the operation of this embodiment having the above-described configuration and a specific method for assembling the expansion joint device will be described. (Installation of inner expansion joint 20) First, a first pipe 1 having a first pipe flange 1A and a second pipe 2 having a second pipe flange 2A are prepared.

[0050] Next, the inner expansion joint 20 is installed between the first pipe flange 1A of the first pipe 1 and the second pipe flange 2A of the second pipe 2.

[0051] In this case, the cylindrical pipe 25 is first extended and installed between the cylindrical extension 24 of the first connection flange 21 and the second connection flange 22. Next, the second sealant 37 is placed between the cylindrical pipe 25 and the end 24a of the cylindrical extension 24 of the first connection flange 21 near the second connection flange 22, and the second sealant 37 is held by the holder 32. This holder 32 is attached to the cylindrical extension 24 with mounting bolts 34 and nuts 35. In this case, nuts 35 and lock nuts 36 are attached to the mounting bolts 34 in this order, and the holder 32 is fixed to the cylindrical extension 24.

[0052] Next, the first connection flange 21 is fixed to the first piping flange 1A with bolts 21A and nuts 21B, and the second connection flange 22 is fixed to the second piping flange 2A with bolts 22A and nuts 22B, thus fixing the inner expansion joint 20 between the first piping flange 1A and the second piping flange 2A (see FIG. 1).

[0053] In this case, the first piping flange 1A and the first connection flange 21 are brought into contact with each other, bolts 21A are inserted into the bolt holes of the first piping flange 1A and the first connection flange 21, and the ends of the bolts 21A are tightened with nuts 21B. This fixes the first connection flange 21 to the first piping flange 1A. The first connection flange 21 is also provided with a third seal member 21b in advance to seal the gap between the first piping flange 1A and the first connection flange 21.

[0054] Furthermore, the second piping flange 2A and the second connection flange 22 are brought into contact with each other, bolts 22A are inserted into the bolt holes of the second piping flange 2A and the second connection flange 22, and the ends of the bolts 22A are tightened with nuts 22B. This allows the second connection flange 22 to be fixed to the second piping flange 2A. Furthermore, the flange 25a of the cylindrical pipe 25 is provided in advance with a first sealant 25b that seals the gap between the second piping flange 2A and the flange 25a. In this way, the inner expansion joint 20 can be fixed between the first piping flange 1A and the second piping flange 2A. (Installation of outer expansion joint 40) If a leak occurs between the first pipe 1 and the second pipe 2, the inner expansion joint 20 provided between the first pipe flange 1A and the second pipe flange 2A alone may not be able to completely prevent the leaked liquid from flowing outward.

[0055] Therefore, in this embodiment, when the inner expansion joint 20 is installed between the first piping flange 1A and the second piping flange 2A, the outer expansion joint 40 is installed at the same time, or after several months to several years have passed since the inner expansion joint 20 was installed.

[0056] Specifically, first, a band-shaped rubber ring 41 is prepared.

[0057] Next, a band-shaped rubber ring 41 is wrapped circumferentially around the outer peripheries of the first connection flange 21 and the second connection flange 22. Next, both ends of the rubber ring 41 are butted together and vulcanization bonded, thereby attaching the rubber ring 41 to the outer peripheries of the first connection flange 21 and the second connection flange 22. Alternatively, both ends of the rubber ring 41 may be bonded using an instant adhesive.

[0058] In this case, a pair of fixing portions 42 of the rubber ring 41 are fixed to the outer periphery of the first connecting flange 21 and the outer periphery of the second connecting flange 22. At this time, the protruding pieces 42a of the fixing portions 42 are engaged with the protrusions 21a provided on the outer periphery of the first connecting flange 21 and the protrusions 22a provided on the outer periphery of the second connecting flange 22, respectively. This allows the fixing portions 42 of the rubber ring 41 to be firmly fixed to the outer periphery of the first connecting flange 21 and the outer periphery of the second connecting flange 22.

[0059] Next, a cylindrical cover 50 is placed radially outward of the rubber ring 41 to cover the rubber ring 41 from the outside.

[0060] Specifically, adjacent divided portions 50A, 50A separated along the circumferential direction are joined via their respective joining flanges 61, 61. Then, attachment bolts 62 are inserted into the joining flanges 61, 61, and the attachment bolts 62 are tightened with tightening nuts 63. In this manner, the divided portions 50A, 50A separated along the circumferential direction can be assembled.

[0061] In this case, for each of the divided parts 50A, 50A to be assembled, the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53 are pre-assembled. At this time, the first cylindrical cover part 51 and the second cylindrical cover part 52 are abutted against each other at their mounting flanges 51a, 52a, mounting bolts 55 are inserted into the bolt holes 51b, 52b of the mounting flanges 51a, 52a, and locking nuts 56 are tightened onto the mounting bolts 55.

[0062] Similarly, the second cylindrical cover part 52 and the third cylindrical cover part 53 are abutted against each other by their mounting flanges 52a, 53a, and mounting bolts 55 are inserted into the bolt holes 52b, 53b of the mounting flanges 52a, 53a, and the clamping nuts are tightened onto the mounting bolts 55.

[0063] In this manner, the cylindrical cover 50 that covers the rubber ring 41 from the outside is installed radially outward of the rubber ring 41. In this case, when fixing the divided parts 50A, 50A, the tightening nuts 63 are loosely tightened onto the mounting bolts 62. Similarly, the tightening nuts 56 are loosely tightened onto the mounting bolts 55 for the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53 that make up the divided parts 50A, 50A. This allows the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53 to move relative to each other in the radial direction.

[0064] 3, in each divided portion 50A, 50A, the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 are moved radially relative to one another in response to the radial misalignment between the first pipe 1 and the second pipe 2. In this embodiment, the inner diameters of the bolt holes 51b in the mounting flange 51a of the first cylindrical cover portion 51 and the bolt holes 52b in the mounting flange 52a of the second cylindrical cover portion 52 are larger than the outer diameter of the mounting bolts 55. Also, the inner diameters of the bolt holes 52b in the mounting flange 52a of the second cylindrical cover portion 52 and the bolt holes 53b in the mounting flange 53a of the third cylindrical cover portion 53 are larger than the outer diameter of the mounting bolts 55. This allows the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53 to be easily and reliably moved radially relative to each other in response to radial misalignment between the first piping 1 and the second piping 2.

[0065] After the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 are moved radially relative to each other in this manner in response to the radial displacement between the first pipe 1 and the second pipe 2, the tightening nuts 56 are tightly tightened onto the mounting bolts 55 inserted into the mounting flanges 51a and 52a. The tightening nuts 56 are also tightly tightened onto the mounting bolts 55 inserted into the mounting flanges 52a and 53a. In this manner, the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 are fixed.

[0066] Thereafter, the clamping nuts 63 are tightly tightened onto the mounting bolts 62 that secure the divided parts 50A, 50A together, thereby fixing the divided parts 50A, 50A together.

[0067] In this way, the cylindrical cover 50 that covers the rubber ring 41 from the outside can be installed radially outward of the rubber ring 41 .

[0068] In the above embodiment, an example has been shown in which the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 are moved relative to each other in the radial direction in response to the radial misalignment between the first pipe 1 and the second pipe 2, and then the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 are fixed. However, this is not limiting, and if there is no radial misalignment between the first pipe 1 and the second pipe 2, the first cylindrical cover portion 51, the second cylindrical cover portion 52, and the third cylindrical cover portion 53 may be fixed in advance so as to be aligned in a straight line.

[0069] In this case, there is no need to loosely tighten the fastening nuts 63 onto the mounting bolts 62 that secure the divided parts 50A, 50A together, and the fastening nuts 63 can be firmly tightened onto the mounting bolts 62 in one go.

[0070] As described above, according to this embodiment, even if water leakage occurs from the inner expansion joint 20 arranged between the first pipe 1 and the second pipe 2 and the leaked liquid flows into the sealed space 10A, the rubber ring 41 of the outer expansion joint 40, particularly the corrugated portion 41A of the rubber ring 41, expands radially outward, preventing the fluid in the sealed space 10A from being discharged to the outside. At the same time, the corrugated portion 41A of the rubber ring 41 expands radially outward, and can absorb the pressure of the fluid that has flowed into the sealed space 10A.

[0071] Furthermore, because fixing portions 42 of rubber ring 41 are firmly fixed to the outer peripheries of first connection flange 21 and second connection flange 22, rubber ring 41 will not come off the outer peripheries of first connection flange 21 and second connection flange 22. Furthermore, because protruding pieces 42a of fixing portions 42 engage with protrusions 21a provided on the outer periphery of first connection flange 21 and protrusions 22a provided on the outer periphery of second connection flange 22, rubber ring 41 will not come off the outer peripheries of first connection flange 21 and second connection flange 22, even if first piping 1 and second piping 2 move apart in the axial direction.

[0072] Furthermore, since a cylindrical cover 50 that covers the rubber ring 41 is provided radially outward of the rubber ring 41 of the outer expansion joint 40, when liquid flows into the sealed space 10A and the corrugated portion 41A of the rubber ring 41 expands radially outward, the cylindrical cover 50 can press down on the corrugated portion 41A from the outside. This prevents the corrugated portion 41A of the rubber ring 41 from expanding significantly radially outward.

[0073] In this embodiment, the cylindrical cover 50 is divided in the axial direction into three cylindrical cover portions 51, 52, and 53. When viewed in a cross section parallel to the axis C, each of the cylindrical cover portions has a linear shape parallel to the axis C (see FIG. 1).

[0074] 1, the three cylindrical cover portions 51, 52, and 53 are aligned in a straight line along the axis C. Therefore, the three cylindrical cover portions 51, 52, and 53 can regulate the outer edge of the corrugated portion 41A of the rubber ring 41. In this case, since the cylindrical cover portions 51, 52, and 53 all have a straight line shape, the outer regions of the cylindrical cover portions 51, 52, and 53 can be widely used. In other words, if the cylindrical cover 50 is not installed radially outward of the rubber ring 41, the corrugated portion 41A of the rubber ring 41 may expand radially outward to a large extent and come into contact with a structure installed radially outward of the rubber ring 41.

[0075] According to this embodiment, the cylindrical cover 50 is installed radially outward from the rubber ring 41, and the cylindrical cover portions 51, 52, and 53 of the cylindrical cover 50 have a linear shape, so that the rubber ring 41 does not come into contact with structures installed radially outward from the rubber ring 41, and there is no problem even if structures are installed over a wide range radially outward from the cylindrical cover portions 51, 52, and 53.

[0076] Furthermore, even if a radial misalignment occurs between the first pipe 1 and the second pipe 2, the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53 can be moved radially in response to this radial misalignment, thereby absorbing the radial misalignment that occurs between the first pipe 1 and the second pipe 2 by the first cylindrical cover part 51, the second cylindrical cover part 52, and the third cylindrical cover part 53.

[0077] Furthermore, the outer expansion joint 40 can be retrofitted to the outer periphery of the first connection flange 21 and the second connection flange 22 several months or years after the inner expansion joint 20 is installed between the first pipe 1 and the second pipe 2. Therefore, the outer expansion joint 40 can be installed in a manner that reinforces the existing inner expansion joint 20, utilizing the existing inner expansion joint 20.

[0078] The rubber ring 41 also has a corrugated portion 41A. Therefore, even if water leaks from the inner expansion joint 20 and fluid flows into the sealed space 10A, the corrugated portion 41A can expand and absorb the pressure of the fluid. When attaching the cylindrical cover 50 to the radially outer side of the rubber ring 41, the corrugated portion 41A is pressed radially inward beforehand. This prevents the corrugated portion 41A from getting in the way when attaching the cylindrical cover 50, expanding the working space and making it easier to attach the cylindrical cover 50.

[0079] Furthermore, since the rubber ring 41 is covered radially outward by the cylindrical cover 50, it is not necessary to make the rubber ring 41 particularly strong to withstand the pressure of the fluid within the sealed space 10A.

[0080] Furthermore, since the rubber ring 41 is covered radially outward by the cylindrical cover 50, the rubber ring 41 will not be hit by a structure or subjected to unintended external forces, and the rubber ring 41 will not be deteriorated by direct sunlight, etc. [Explanation of symbols]

[0081] 1. First piping 1A First piping flange 2. Second piping 2A Second piping flange 10 Expansion joint device 20 Inner expansion joint 21 First connection flange 21A Volt 21B Nut 22 Second connection flange 22A Volts 22B Nut 24 Cylindrical extension 24a end 25 Cylindrical tube 25a flange 25b First sealing material 32 Holding body 34 Mounting bolt 35 Nut 37 Second sealing material 40 Outer expansion joint 41 Rubber ring 41A Wave shape section 42 Fixed part 50 Cylindrical cover 50A split part 51 first cylindrical cover portion 51a Mounting flange 51b Bolt hole 52 second cylindrical cover portion 52a Mounting flange 52b bolt hole 53 Third cylindrical cover part 53a Mounting flange 53b Bolt hole 55 Mounting bolt 56 Clamping nut

Claims

1. An expansion joint device connecting a cylindrical first pipe having a first pipe flange and a cylindrical second pipe having a second pipe flange, an inner expansion joint connected to the first piping flange and the second piping flange; an outer expansion joint disposed radially outward of the inner expansion joint; the inner expansion joint has a first connection flange connected to the first piping flange, a second connection flange connected to the second piping flange, and a cylindrical body extending between the first connection flange and the second connection flange, the outer expansion joint is provided between the first connection flange and the second connection flange, and has a rubber ring extending along the circumferential direction, and a cylindrical cover attached radially outward of the rubber ring and covering the rubber ring from the outside, an expansion joint device.

2. 2. The expansion joint device according to claim 1, wherein the rubber ring has a wave-shaped portion when the expansion joint device is viewed in a cross section parallel to the axis.

3. 2. The expansion joint device according to claim 1, wherein, when the expansion joint device is viewed in a cross section parallel to the axis, the cylindrical cover is parallel to the axis and has a shape that covers the rubber ring from the outside.

4. The expansion joint device according to claim 1 , wherein the cylindrical cover has a plurality of cylindrical cover portions that are separable in the axial direction.

5. 5. The expansion joint apparatus of claim 4, wherein the first cylindrical cover portion is radially movable relative to the adjacent second cylindrical cover portion.

6. 6. The expansion joint apparatus of claim 5, wherein a first mounting flange of the first cylindrical cover portion interfaces with a second mounting flange of the second cylindrical cover portion, mounting bolts are inserted through bolt holes in the first mounting flange and bolt holes in the second mounting flange, and inner diameters of the bolt holes for the first mounting bolts and the bolt holes for the second mounting bolts are larger than outer diameters of the mounting bolts.

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