Expansion joints

Abstract

Provided is an expansion joint that, when providing a sensor inside a bellows material of the expansion joint, allows a sensor to be introduced inside the bellows material while maintaining the airtightness of the bellows material. [Solution] An expansion joint 20 that connects an upstream duct 11 and a downstream duct 12 through which a fluid flows and through which the expansion joint 20 has an expansion property and prevents the outflow of the fluid, and is provided between the upstream duct 11 and the downstream duct 12, a heat insulating section 30 that is provided inside the bellows material 23 and insulates the heat of the fluid, and an FBG sensor 40 that is provided inside the bellows material 23, and the bellows material 23 is formed in a cylindrical shape along the circumferential direction, and the FBG sensor 40 of the bellows material 23 is introduced inside the bellows material 23 via a joint 28 of the bellows material 23.

Description

[Technical field]

[0001] This invention relates to expansion joints. [Background technology]

[0002] Expansion joints are used at the connection parts of ducts that transport fluids such as high-temperature gases, which are installed in facilities such as thermal power plants and chemical plants, in order to absorb displacement, vibration, stress, and the like that occurs in the duct itself. As an example of a conventional expansion joint, for example, the expansion joint described in Patent Document 1 is known. This expansion joint is formed by connecting a pair of flanges formed so as to be connectable to a duct, with a cylindrical non-metallic bellows material having expansion and contraction flexibility, and a heat insulating part installed inside the bellows material, and a plurality of thermal fuses are arranged in the heat insulating part. Then, a disconnection state of the thermal fuses is detected via the conductors connected to these thermal fuses, and a decrease in the heat insulating function of the heat insulating part is detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-27189 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the expansion joint described in Patent Document 1, in order to detect the disconnection state of the thermal fuse arranged in the heat insulating part, it is necessary to introduce a conductor wire for connecting to the thermal fuse into the inside of the expansion joint. However, when a through hole for introducing the conductor wire into the inside of the expansion joint is provided in the bellows material, there is a problem in that it becomes difficult to maintain the airtightness of the bellows material.

[0005] The present invention has been made to solve such problems, and has an object to provide an expansion joint that, when a sensor is provided inside the bellows material of an expansion joint, allows the sensor to be introduced inside the bellows material while maintaining the airtightness of the bellows material. [Means for solving the problem]

[0006] In order to solve the above problems, the expansion joint of the present invention is an expansion joint that connects a first duct and a second duct through which a fluid flows and through which a fluid flows, and is equipped with an outflow prevention part that is provided between the first duct and the second duct and has elasticity to prevent the outflow of the fluid, and a sensor provided inside the outflow prevention part, the outflow prevention part is formed in a cylindrical shape along the circumferential direction and has a joint between the ends, and the sensor is introduced from the outside of the outflow prevention part to the inside of the outflow prevention part via the joint of the outflow prevention part.

[0007] The joint may be formed by joining an inner surface of one end of the outflow prevention portion to an inner surface of the other end of the outflow prevention portion, and protruding radially outward from the outflow prevention portion. In addition, the outflow prevention portion may be formed by joining a plurality of outflow prevention members, and at least two joint portions may be formed by joining the ends of adjacent outflow prevention members among the plurality of outflow prevention members. The sensor may be led from the inside of the outflow prevention portion to the outside of the outflow prevention portion via at least one of the joints of the outflow prevention portion. In addition, a plurality of sensors may be provided adjacent to the joint of the outflow prevention portion. Furthermore, a plurality of sensors may be provided at intervals from each other at the joint of the outflow prevention portion. A filler may be filled into the gap between the joint and the sensor. The fluid pipeline may also have a fluid conduit therein through which a heat transfer medium can flow, and the fluid conduit may be introduced from the outside of the outflow prevention part via the joint to the inside of the outflow prevention part, and may be led from the inside of the outflow prevention part to the outside of the outflow prevention part via the joint. Effect of the Invention

[0008] The expansion joint of the present invention comprises an outflow prevention section which is elastic and prevents the outflow of fluid, and a sensor provided inside the outflow prevention section, the outflow prevention section being formed in a cylindrical shape along the circumferential direction and having a joint between the ends, and the sensor being introduced from the outside of the outflow prevention section to the inside of the outflow prevention section via the joint of the outflow prevention section, so that when the sensor is provided inside the bellows material of the expansion joint, the sensor can be introduced inside the bellows material while maintaining the airtightness of the bellows material. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a non-metallic expansion joint in accordance with a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the upstream duct, downstream duct, and expansion joint shown in FIG. [Diagram 3] 1 is a cross-sectional view taken along a radial direction of a protective tube and an FBG sensor according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram of an FBG sensor provided in an expansion joint according to the first embodiment of the present invention. [Diagram 5] FIG. 1 is a schematic perspective view showing a bellows material of an expansion joint according to a first embodiment of the present invention. [Figure 6] 6 is a schematic diagram showing joint surfaces of a first end and a second end of the joint shown in FIG. 5. FIG. [Figure 7] FIG. 11 is a schematic perspective view showing a bellows material of an expansion joint according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a schematic perspective view showing a bellows material of an expansion joint according to embodiment 3 of the present invention. [Figure 9] 9 is a schematic diagram showing a joint surface between a first end and a second end of the joint shown in FIG. 8. FIG. [Figure 10] FIG. 11 is a schematic diagram of an expansion joint and an FBG sensor according to a fourth embodiment of the present invention. [Figure 11] FIG. 11 is a schematic perspective view showing a bellows material of an expansion joint according to embodiment 4 of the present invention. [Figure 12]12 is a schematic diagram showing a joint surface between a first end and a second end of the joint shown in FIG. 11. FIG. [Figure 13] 13 is a schematic diagram showing a joint surface between a first end and a second end of a joint portion of a bellows material according to a fifth embodiment. FIG. [Figure 14] FIG. 13 is a schematic perspective view showing a bellows material of an expansion joint according to a sixth embodiment of the present invention. [Figure 15] 15 is a schematic diagram showing a joint surface between a first end and a second end of the joint portion shown in FIG. 14. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiment 1 Hereinafter, an expansion joint according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a non-metallic expansion joint according to the first embodiment. In the first embodiment, a duct structure 1 arranged in a thermal power generation facility or the like has a cylindrical upstream duct 11 and a downstream duct 12 through which a high-temperature fluid such as exhaust gas flows. An expansion joint 20, which is a non-metallic expansion joint provided in the duct structure 1, is arranged between the upstream duct 11 and the downstream duct 12 to connect the two ducts and prevent the internal fluid from flowing out. In addition, the expansion joint 20 absorbs the variation in the gap between the upstream duct 11 and the downstream duct 12 due to the expansion and contraction of the upstream duct 11 and the downstream duct 12, and also absorbs vibrations and the like that occur in the upstream duct 11 and the downstream duct 12 due to the flow of the fluid. Note that the expansion joint 20 shown in FIG. 1 is exemplified as being cylindrical, but the actual shape is not limited to this, and it is common to have a structure that matches the shape of the duct structure to be connected, and for example, a square tube shape can also be used.

[0011] The expansion joint 20 has a flange 21 connected to the upstream duct 11, a flange 22 connected to the downstream duct 12, and a bellows material 23 provided between the flanges 21 and 22 to airtightly connect these flanges. The pair of flanges 21, 22 and the bellows material 23 are configured in a cylindrical shape to match the cylindrical shapes of the upstream duct 11 and the downstream duct 12. The upstream duct 11 is formed with a duct flange 14, and the flange 21 is formed to correspond to the duct flange 14. The expansion joint 20 and the upstream duct 11 are airtightly connected by connecting the flange 21 and the duct flange 14 (for example, fastening with bolts, etc.). The downstream duct 12 is formed with a duct flange 15, and the flange 22 is formed to correspond to the duct flange 15. The expansion joint 20 and the downstream duct 12 are airtightly connected by connecting the flange 22 and the duct flange 15 (for example, fastening with bolts, etc.). Furthermore, the flanges 21 and 22 can be made of any metal such as stainless steel. The bellows material 23 has a dimension required for the distance between both ends of the expansion joint 20 (the connection surfaces with the upstream duct 11 and the downstream duct 12) to be sufficiently longer than the separation distance between the upstream duct 11 and the downstream duct 12 to be connected. Then, by attaching the expansion joint 20 between the upstream duct 11 and the downstream duct 12 with the bellows material 23 in a slackened state, the thermal expansion and contraction, vibration, and the like of both ducts are absorbed.

[0012] Fig. 2 is a schematic cross-sectional view of the upstream duct 11, downstream duct 12, and expansion joint 20 shown in Fig. 1. A baffle plate 13 formed as a cylindrical body with a tip smaller than the inner diameter of the downstream duct 12 is provided on the downstream side of the upstream duct 11. This baffle plate 13 can be made of a metal such as stainless steel. The expansion joint 20 is disposed so that the presence of the baffle plate 13 prevents it from being directly exposed to the fluid passing through the upstream duct 11 and flowing in the direction of arrow A.

[0013] The expansion joint 20 has a bellows material 23 disposed between the flanges 21 and 22 at the outermost radial position to prevent outflow of the fluid flowing through the upstream duct 11 and the downstream duct 12. The bellows material 23 is a cloth-like member formed by stacking four layered members, namely, a first bellows member 24, a second bellows member 25, a third bellows member 26, and a fourth bellows member 27, in that order from the outer radial position. The bellows material 23 is configured to have flexibility to expand and contract along the outflow direction of the fluid indicated by the arrow A and along a direction intersecting the outflow direction. The bellows material 23 forms an expandable portion.

[0014] The first bellows member 24, the second bellows member 25, the third bellows member 26, and the fourth bellows member 27 constituting the bellows material 23 may include any layer such as a sealing layer for preventing the outflow of fluid, a reinforcing layer for reinforcing the strength of the bellows material 23, and a protective layer for protecting the bellows material 23 from the surrounding environment such as the outside air, moisture, and ultraviolet rays, and the bellows material 23 may be formed by combining such any layer in any suitable order. The bellows material 23 is not limited to a four-layer structure, and may be, for example, a structure of one to three layers, or a structure of five or more layers. The first bellows member 24, the second bellows member 25, the third bellows member 26, and the fourth bellows member 27 may be formed by appropriately adopting any known material, such as PTFE (polytetrafluoroethylene), inorganic fiber cloth such as glass cloth, metal fiber cloth, and film-like resin.

[0015] The expansion joint 20 also has a heat insulating section 30 on the radially inner side of the bellows material 23. The heat insulating section 30 insulates the heat of the fluid flowing through the expansion joint 20 and prevents the heat of the fluid from being directly transmitted to the bellows material 23 provided on the radially outer side. The heat insulating section 30 is configured by stacking five layers of heat insulating members, namely, a first heat insulating member 31, a second heat insulating member 32, a third heat insulating member 33, a fourth heat insulating member 34, and a fifth heat insulating member 35, in order from the radially outer side. The first heat insulating member 31, the second heat insulating member 32, the third heat insulating member 33, the fourth heat insulating member 34, and the fifth heat insulating member 35 constituting the heat insulating section 30 may include any layer as a heat insulating layer for satisfying conditions such as heat insulating performance, and the heat insulating section 30 may be formed by combining such any layer in any suitable order. The heat insulating section 30 is not limited to a configuration in which five layers of members are stacked, and may be configured, for example, by 1 to 4 layers of members, or by 6 or more layers of members.

[0016] The first insulating member 31, the second insulating member 32, the third insulating member 33, the fourth insulating member 34, and the fifth insulating member 35 constituting the insulating section 30 may be formed by appropriately adopting any known material. The first insulating member 31, the second insulating member 32, the third insulating member 33, the fourth insulating member 34, and the fifth insulating member 35 may be formed, for example, by wrapping inorganic fiber felt such as glass felt, ceramic felt, or alumina felt with inorganic fiber cloth such as glass cloth, ceramic cloth, or alumina cloth, and optionally wrapping this with a net (mesh, etc.) woven with appropriate metal wires such as steel wires such as stainless steel wires, Inconel (registered trademark) wires, or copper wires, or alternatively by wrapping with organic fibers or organic films such as PTFE.

[0017] A protective tube 37 made of stainless steel is wound spirally around the circumferential direction of the expansion joint 20 on the radial outside of the first insulating member 31 and the second insulating member 32 of the expansion joint 20, and an FBG sensor 40 is inserted inside the protective tube 37. That is, the FBG sensor 40 is disposed on the radial outside of the insulating part 30 and on the radial inside of the bellows material 23.

[0018] 3 is a cross-sectional view taken along a radial direction of the protective tube 37 and the FBG sensor 40 according to the embodiment 1. That is, the FBG sensor 40 is housed in the protective tube 37 made of stainless steel, and is wound around the radial outside of the thermal insulation part 30 shown in FIG.

[0019] Fig. 4 is a schematic diagram of an FBG sensor 40 provided in the expansion joint 20 according to the first embodiment. For ease of explanation, Fig. 4 omits the illustration of some components of the expansion joint 20, such as the flanges 21 and 22, the bellows material 23, and the protective tube 37. The FBG sensor 40 is disposed on the radially outer side of the thermal insulation section 30 of the expansion joint 20, wound three times in a clockwise spiral shape as viewed from the downstream side in the flow direction of the fluid indicated by the arrow A. That is, the FBG sensor 40 is disposed on the radially inner side of the bellows material 23 (see Fig. 2), wound three times in a spiral shape along the circumferential direction.

[0020] The FBG sensor 40 is an optical fiber temperature sensor having a cladding portion whose surface is covered with polyimide resin and a core portion disposed inside the cladding portion, and a plurality of diffraction gratings 43 formed in the core portion by laser processing at predetermined intervals in the extending direction of the optical fiber. The FBG sensor 40 is spirally wound around the radially outer side of the thermal insulation portion 30, so that a plurality of diffraction gratings 43 are disposed in both the fluid flow direction indicated by the arrow A and the circumferential direction of the thermal insulation portion 30 of the expansion joint 20. Note that a diffraction grating 43 is also disposed in the portion of the FBG sensor 40 hidden by the expansion joint 20 and indicated by the dashed line in FIG. 4.

[0021] The FBG sensor 40 is connected to an interrogator 44 provided outside the expansion joint 20. The interrogator 44 has a light source device that makes light incident on the FBG sensor 40 and a light wavelength measurement device that measures and analyzes the wavelength of the reflected light from each diffraction grating 43, and is disposed in an appropriate weatherproof case.

[0022] FIG. 5 is a schematic perspective view showing the bellows material 23 of the expansion joint 20 according to the first embodiment. The bellows material 23 is formed in a cylindrical shape along the circumferential direction of the expansion joint 20. The bellows material 23 is formed so that the length in the longitudinal direction when cut is longer than the circumferential length of the expansion joint 20. The first end 28a and the second end 28b of the bellows material 23 in the direction along the circumferential direction of the expansion joint 20 are joined together to form an integrated cloth-like joint 28. The joint 28 is provided by joining the faces of the first end 28a and the second end 28b of the bellows material 23 that are continuous with the faces facing the radially inner side of the expansion joint 20, and protruding outward in the radial direction of the expansion joint 20. As a result, the joint 28 is formed to be rotatable so as to turn around along the circumferential direction of the expansion joint 20 with the base as a fulcrum. Between the first end 28a and the second end 28b of the joint 28, a protective tube 37 and an FBG sensor 40 arranged inside the protective tube 37 are provided, and the protective tube 37 and the FBG sensor 40 are introduced into the inside of the expansion joint 20 from the joint 28. That is, the joint 28 constitutes an introduction path for the protective tube 37 and the FBG sensor 40. The protective tube 37 is provided on the outside of the joint 28 by a predetermined length. In the first embodiment, the joint 28 is formed in a cloth shape that can be turned around in the circumferential direction of the expansion joint 20, but the present invention is not limited to this, and may be formed in any configuration and shape that is not fixed in a fixed position as a whole and can be freely moved.

[0023] FIG. 6 is a schematic diagram showing the joint surface between the first end 28a and the second end 28b of the joint portion 28 shown in FIG. 5, as viewed from the radial outside. In a region B of the joint surface between the first end 28a and the second end 28b, where the protective tube 37 is not provided, the first end 28a and the second end 28b are integrated by thermal fusion. In a region C of the joint surface between the first end 28a and the second end 28b, where the protective tube 37 is provided, the first end 28a and the second end 28b are not thermally fused. As a result, the region C of the first end 28a and the second end 28b forms an introduction path through which the protective tube 37 and the FBG sensor 40 can be inserted or removed. In the region C, the first end 28a and the second end 28b may be provided in close contact with the protective tube 37, or may be provided in contact with the protective tube 37 to the extent that they are not in close contact with each other. The joining means for the first end 28a and the second end 28b in region B is not limited to integration by thermal fusion, and any joining means such as adhesion using an adhesive may be used.

[0024] Next, the operation of the expansion joint 20 according to the first embodiment will be described. A thermal power generation facility or the like according to the first embodiment has a duct structure 1 in which the expansion joint 20 shown in Fig. 1 is provided. During operation of the thermal power generation facility or the like, high-temperature gas flows through the duct structure 1 and the expansion joint 20. An interrogator 44 shown in Fig. 4 directs light into the FBG sensor 40 and measures and analyzes the wavelength of the reflected light from each diffraction grating 43.

[0025] During operation of a thermal power plant or the like, if damage occurs to a part of the heat insulating part 30 of the expansion joint 20 shown in FIG. 2 due to aging, abnormal operation, interference of foreign matter in the fluid, or the like, the heat insulating performance that blocks the heat of the fluid flowing inside is partially reduced. Therefore, the temperature of the heat insulating part 30, the bellows material 23, and the surroundings on the radially outer side of the part where the heat insulating performance of the heat insulating part 30 has decreased increases more than before the decrease in heat insulating performance. This increases the temperature of the diffraction grating 43 (see FIG. 4) disposed near the part where the heat insulating performance of the heat insulating part 30 has decreased. Due to this increase in temperature of the diffraction grating 43, the wavelength of the reflected light from the diffraction grating 43 changes (shifts) in response to the temperature increase. The interrogator 44 measures the wavelength of this reflected light, compares the change in wavelength with the wavelength before the change, and analyzes it, thereby making it possible to detect which of the diffraction gratings 43 provided in the FBG sensor 40 has experienced a temperature change. Then, it is possible to identify that the heat insulating part 30 has deteriorated near the diffraction grating 43 where the temperature change has occurred. That is, it is possible to identify the location of the expansion joint 20 where deterioration of the heat insulating section 30 has occurred.

[0026] In addition, damage may occur to a part of the bellows material 23 of the expansion joint 20 shown in FIG. 2 due to heat, external force, or the like, and the airtightness of the bellows material 23 may be impaired. In this case, the internal fluid or external air flows inside and outside the bellows material 23 at the location where the damage occurred, and the temperature of the heat insulating section 30 located radially inside the location where the damage occurred and its surroundings may rise or fall compared to before the damage occurred. This causes the temperature of the diffraction grating 43 (see FIG. 4) disposed near the location where the damage occurred to rise or fall. The rise or fall in temperature of the diffraction grating 43 changes the wavelength of the reflected light from the diffraction grating 43. The interrogator 44 compares the change in the wavelength of the reflected light with the wavelength before the change and analyzes it, thereby detecting which diffraction grating 43 of the FBG sensor 40 has experienced the temperature change. Then, it is possible to identify that the damage to the bellows material 23 has occurred near the diffraction grating 43 where the temperature change occurred. In other words, it is possible to identify the location of the expansion joint 20 where the damage to the bellows material 23 has occurred.

[0027] In conventional expansion joints, a method for providing a sensor such as an FBG sensor inside a bellows material may involve providing a through hole in the bellows material and introducing the sensor itself or a conductor connected to the sensor into the through hole. However, when using such a method, there is a problem in that it is difficult to maintain airtightness even when a filler or the like is used, because the length of the through hole in the radial direction of the expansion joint 20 (i.e., the length from the inlet to the outlet) is only the thickness of the bellows material.

[0028] On the other hand, in the first embodiment, in assembling the expansion joint 20 shown in Fig. 2, the protective tube 37 is wound around the thermal insulation section 30, and the first end 28a and the second end 28b of the bellows material 23 are joined with the vicinity of the end of the protective tube 37 sandwiched between them as shown in Figs. 5 and 6, and the end of the protective tube 37 is provided a predetermined length outside from the joint 28. Then, the FBG sensor 40 is inserted into the protective tube 37 and the FBG sensor 40 is wound around the thermal insulation section 30. As a result, the protective tube 37 and the FBG sensor 40 are introduced into the inside of the bellows material 23 from the joint 28. Furthermore, in region C of the joint surface between the first end 28a and the second end 28b of the joint 28, the first end 28a and the second end 28b are in close contact with the protective tube 37 or the first end 28a and the second end 28b are in contact with the protective tube 37, so that there is no or almost no gap between the first end 28a and the second end 28b and the protective tube 37, and the length from the entrance to the exit of the through hole is long enough to cross the joint 28, so that the FBG sensor 40 is introduced from the outside to the inside of the bellows material 23 while maintaining the airtightness of the bellows material 23.

[0029] Furthermore, in conventional expansion joints, as described above, the length of the through hole in the bellows material in the radial direction of the expansion joint 20 is only equal to the thickness of the bellows material. Therefore, even if a filler or the like is used, it is difficult to maintain strength due to the presence of the through hole, and there is a problem in that damage is likely to occur near the through hole when internal fluid pressure is applied.

[0030] On the other hand, in this embodiment 1, the through hole formed in region C of the joint 28 between the first end 28a and the second end 28b has a length from the inlet to the outlet that crosses the joint 28, so that the strength of the through hole is maintained even when internal fluid pressure is applied, which has the advantage of reducing the possibility of damage to the bellows material 23 near the through hole.

[0031] In addition, in conventional expansion joints, as a means for providing a sensor such as an FBG sensor inside the bellows material, a through hole may be provided in the metal flange that holds the bellows material and the heat insulating material, and the sensor itself or a lead wire connected to the sensor may be introduced into the through hole, or the sensor itself or the lead wire of the sensor may be introduced into the joint surface between the flange and the bellows material. However, in this case, the airtightness of the portion where the sensor itself or the lead wire of the sensor is introduced is compensated for by a gasket or sealant, so there is no freedom in the position or angle of the sensor introduction, and there are problems in that the metal flange becomes hot, accelerating the deterioration rate of the sealant and the sensor. Furthermore, when the sensor itself or a lead wire connected to the sensor is introduced into an expansion joint in this way, the direction of introduction and the direction of expansion and contraction of the expansion joint are roughly the same, and the sensor itself or the lead wire connected to the sensor is firmly fixed. As a result, the sensor is bent due to movement of the bellows material, insulation material, etc. caused by the expansion and contraction of the expansion joint. Also, vibrations of the duct caused by the operation of equipment having piping in which an expansion joint is installed are transmitted to the expansion joint, and distortion due to the vibrations is concentrated at the point where the sensor is fixed to the expansion joint, accelerating the rate of deterioration of the sensor.

[0032] On the other hand, in the first embodiment, the joint 28, which is the introduction path for the protective tube 37 and the FBG sensor 40, is a part of the flexible bellows material 23, and is formed to be rotatable around the base in the radial direction of the expansion joint 20, so that the degree of freedom of the insertion position and angle of the FBG sensor 40 is high. In addition, since the protective tube 37 and the FBG sensor 40 are introduced from this joint 28, the thermal conductivity to the FBG sensor 40 is reduced, and further, the transmission of vibration to the FBG sensor 40 is reduced, so that the possibility of the FBG sensor 40 breaking down due to heat or vibration can be reduced.

[0033] Furthermore, in this embodiment 1, the first end 28a and the second end 28b are not joined in region C of the joint 28 of the bellows material 23. Therefore, if it becomes necessary to replace the FBG sensor 40 or the protective tube 37, the FBG sensor 40 and the protective tube 37 can be easily replaced without disassembling the expansion joint 20.

[0034] In this way, the expansion joint 20 of the first embodiment is an expansion joint 20 that connects between the upstream duct 11 and the downstream duct 12 through which a fluid flows, and through which the fluid flows, and includes a bellows material 23 that is provided between the upstream duct 11 and the downstream duct 12 and has elasticity to prevent the outflow of the fluid, a heat insulating section 30 that is provided inside the bellows material 23 and insulates the heat of the fluid, and an FBG sensor 40 that is provided inside the bellows material 23, and the bellows material 23 is formed in a cylindrical shape along the circumferential direction and has a joint 28 between the first end 28a and the second end 28b, and the FBG sensor 40 of the bellows material 23 is introduced from the outside of the bellows material 23 to the inside of the bellows material 23 via the joint 28 of the bellows material 23, so that it is possible to provide an expansion joint that allows the FBG sensor 40 to be introduced into the inside of the bellows material 23 while maintaining the airtightness of the bellows material 23.

[0035] In addition, the joint 28 is formed by joining the inner surface of the first end 28a of the bellows material 23 to the inner surface of the second end 28b of the bellows material 23, and protruding radially outward from the bellows material 23. This increases the degree of freedom in the insertion position and angle of the FBG sensor 40, reduces the thermal conductivity to the FBG sensor 40, and further reduces the transmission of vibration to the FBG sensor 40, thereby reducing the possibility of the FBG sensor 40 failing due to heat or vibration.

[0036] Embodiment 2 Next, an expansion joint according to a second embodiment of the present invention will be described. In the following embodiments, the same reference characters as those in Fig. 1 to Fig. 6 indicate the same or similar components, and detailed descriptions thereof will be omitted. The expansion joint according to the second embodiment further includes a joint portion in which an output path of the FBG sensor is provided, in addition to the components in the first embodiment. 7 is a schematic perspective view showing the bellows material of the expansion joint 20 according to the second embodiment. A first bellows material 50 and a second bellows material 51 constituting the bellows material are formed in a cylindrical shape along the circumferential direction of the expansion joint 20. The first bellows material 50 is formed so that its longitudinal length when cut is longer than the longitudinal length of the second bellows material 51 when cut. In addition, the total longitudinal length of the first and second bellows materials 50, 51 when cut is longer than the circumferential length of the expansion joint 20.

[0037] The first end 52a of the first bellows material 50 and the second end 52b of the second bellows material 51 in the circumferential direction of the expansion joint 20 are joined together to form a first joint 52. The first joint 52 is provided by joining the surfaces of the first end 52a of the first bellows material 50 and the second end 52b of the second bellows material 51, which are continuous with the surfaces facing the radially inner side of the expansion joint 20, to each other, and protruding outward in the radial direction of the expansion joint 20. As a result, the first joint 52 is formed to be rotatable so as to turn around the base in the radial direction of the expansion joint 20. Between the first end 52a of the first bellows material 50 and the second end 52b of the second bellows material 51, which constitute the first joint 52, the protective tube 37 and the FBG sensor 40 arranged inside the protective tube 37 are introduced from the outside to the inside of the expansion joint 20. That is, the first joint 52 forms an introduction path for the FBG sensor 40. The protective pipe 37 is provided on the outside of the expansion joint 20 by a predetermined length.

[0038] The second end 53a of the first bellows material 50 and the first end 53b of the second bellows material 51 in the circumferential direction of the expansion joint 20 are joined together to form a second joint 53. The second joint 53 is provided by joining the surfaces of the second end 53a of the first bellows material 50 and the first end 53b of the second bellows material 51, which are continuous with the surfaces facing the radially inner side of the expansion joint 20, to each other, and protruding outward in the radial direction of the expansion joint 20. As a result, the second joint 53 is formed to be rotatable so as to turn around the base in the radial direction of the expansion joint 20. Between the second end 53a of the first bellows material 50 and the first end 53b of the second bellows material 51, which constitute the second joint 53, the tip sides of the protective tube 37 and the FBG sensor 40, which were introduced into the inside of the expansion joint 20 from the first joint 52, are led out to the outside of the expansion joint 20. That is, the second joint 53 constitutes an output path for the FBG sensor 40. The protective tube 37 is provided by a predetermined length on the outside of the expansion joint 20. The other configurations are the same as those in the first embodiment.

[0039] In the second embodiment, in assembling the expansion joint 20, the protective tube 37 is wound around the heat insulating section 30, and the first end 52a of the first bellows material 50 and the second end 52b of the second bellows material 51 are joined with the protective tube 37 in between, so that the end of the protective tube 37 is provided outside the first joint 52 by a predetermined length. Also, the second end 53a of the first bellows material 50 and the first end 53b of the second bellows material 51 are joined with the protective tube 37 in between, so that the end of the protective tube 37 is provided outside the second joint 53 by a predetermined length. After that, the FBG sensor 40 is inserted into the protective tube 37 of the first joint 52, and the FBG sensor 40 is wound around the heat insulating section 30. Furthermore, the tip of the FBG sensor 40 can be brought out of the bellows materials 50, 51 from the protective tube 37 of the second joint 53.

[0040] In this way, the protective tube 37 and the FBG sensor 40 are introduced from the outside to the inside of the bellows material 23 through the first joint 52, and the protective tube 37 and the FBG sensor 40 are led from the inside of the bellows material 23 to the outside through the second joint 53. As a result, similar to the first embodiment, the first end 52a and the second end 52b of the first joint 52 are in a state of contact with the protective tube 37 in close contact or not in close contact, and the second end 53a and the first end 53b of the second joint 53 are in a state of contact with the protective tube 37 in close contact or not in close contact, so that the FBG sensor 40 is introduced from the outside to the inside of the first bellows material 50 and the second bellows material 51 while maintaining the airtightness of the first bellows material 50 and the second bellows material 51, and is led from the inside of the first bellows material 50 and the second bellows material 51 to the outside.

[0041] In this way, the bellows material of the expansion joint 20 according to the second embodiment is formed by joining the first bellows material 50 and the second bellows material 51, and the first joint 52 and the second joint 53 are formed in two by joining the first ends 52a and the second ends 52b and the first ends 53b and the second ends 53a of the adjacent bellows materials 50 and 51, respectively. Therefore, it is possible to configure the expansion joint 20 in which the FBG sensor 40 can be introduced from the outside to the inside of the first bellows material 50 and the second bellows material 51, with the first joint 52 serving as an introduction path for the FBG sensor 40 and the second joint 53 serving as an output path for the FBG sensor 40, while maintaining the airtightness of the first bellows material 50 and the second bellows material 51.

[0042] In the second embodiment, two bellows materials, the first bellows material 50 and the second bellows material 51, are used, and two joints, the first joint 52 and the second joint 53, which constitute the inlet and outlet paths of the FBG sensor 40, are provided. However, the number of joints is not limited to two, and three or more bellows materials may be used to provide three or more joints in the bellows, and each of these may be used appropriately as the inlet and outlet paths of the FBG sensor 40.

[0043] Embodiment 3 Next, a description will be given of an expansion joint according to a third embodiment of the present invention. The expansion joint according to the third embodiment differs from the first embodiment in that a plurality of FBG sensors are provided adjacent to each other at the joint of the bellows material. 8 is a schematic perspective view showing a bellows material of an expansion joint 20 according to the third embodiment. At the joint 28 between the first end 28a and the second end 28b of the bellows material 23, a protective tube 37 and an FBG sensor 40 are introduced from the outside to the inside of the expansion joint 20. The tip sides of the introduced protective tube 37 and FBG sensor 40 are led out from the inside to the outside of the expansion joint 20 adjacent to the protective tube 37 and FBG sensor 40 on the introduction side at the joint 28 between the first end 28a and the second end 28b.

[0044] Fig. 9 is a schematic diagram showing the joint surface between the first end 28a and the second end 28b of the joint 28 shown in Fig. 8. In the joint surface between the first end 28a and the second end 28b, in an area C that is not thermally fused, a protective tube 37 and an FBG sensor 40 that are introduced from the outside to the inside of the expansion joint 20, and a protective tube 37 and an FBG sensor 40 that are led from the inside to the outside of the expansion joint 20 are arranged adjacent to each other in parallel. That is, the joint 28 constitutes an introduction path and an extraction path. The other configurations are the same as those of the first embodiment.

[0045] In this way, in the expansion joint 20 according to the third embodiment, multiple FBG sensors 40 are provided adjacent to each other at the joint 28 of the bellows material 23, so that the multiple FBG sensors 40 can be compactly arranged together in the area C where the joint is not thermally fused.

[0046] In the third embodiment, two protective tubes 37 and two FBG sensors 40 are introduced and led out at the joint 28, but three or more protective tubes 37 and three or more FBG sensors 40 may be introduced and led out. In the third embodiment, both the protective tube 37 and the FBG sensor 40 introduced from the outside to the inside of the joint 28 and the protective tube 37 and the FBG sensor 40 led out from the inside to the outside are provided at the joint 28, but only the protective tube 37 and the FBG sensor 40 introduced from the outside to the inside of the expansion joint 20 may be provided, or only the protective tube 37 and the FBG sensor 40 led out from the inside to the outside may be provided.

[0047] Embodiment 4 Next, we will explain an expansion joint according to embodiment 4 of the present invention. The expansion joint according to embodiment 4 differs from embodiment 1 in that multiple FBG sensors are provided at intervals between each other at the joint of the bellows material. FIG. 10 is a schematic diagram of the expansion joint 20 and the FBG sensors 40, 41, 42 according to the fourth embodiment. For convenience of explanation, FIG. 10 omits the illustration of some of the configurations of the expansion joint 20, such as the flanges 21, 22, the bellows material 23, and the protective tube 37. The FBG sensor 40, the FBG sensor 41, and the FBG sensor 42 are provided in this order from the downstream side with respect to the flow direction of the fluid indicated by the arrow A. The FBG sensors 40, 41, 42 are wound in parallel to each other with intervals between them along the circumferential direction on the radially outer side of the thermal insulation section 30 of the expansion joint 20. That is, the FBG sensors 40, 41, 42 are wound in parallel to each other with intervals between them along the circumferential direction on the radially inner side of the bellows material 23 of FIG. 11, which will be described in detail later.

[0048] 11 is a schematic perspective view of the bellows material 23 of the expansion joint 20 according to the embodiment 4. At the joint 28 between the first end 28a and the second end 28b of the bellows material 23, a protective tube 37 and an FBG sensor 40, a protective tube 37 and an FBG sensor 41, and a protective tube 37 and an FBG sensor 42 are introduced from the outside to the inside of the bellows material 23 with a gap therebetween.

[0049] FIG. 12 is a schematic diagram showing the joint surface between the first end 28a and the second end 28b of the joint 28 shown in FIG. 11. The joint surface between the first end 28a and the second end 28b has an area C1, an area C2, and an area C3 that are not thermally fused, which are provided in order at equal intervals. In an area B where the areas C1, C2, and C3 are not provided, the first end 28a and the second end 28b are integrated by thermal fusion. In the area C1, a protective tube 37 and an FBG sensor 40 are provided, which are introduced from the outside to the inside of the expansion joint 20. In the area C2, a protective tube 37 and an FBG sensor 41 are provided, which are introduced from the outside to the inside of the expansion joint 20. In the area C3, a protective tube 37 and an FBG sensor 42 are provided, which are introduced from the outside to the inside of the expansion joint 20. The other configurations are the same as those of the first embodiment.

[0050] In this way, in the expansion joint 20 of this fourth embodiment, multiple FBG sensors 40, 41, 42 are provided at intervals from each other at the joint 28 of the bellows material 23, which makes it easy to wire each sensor when multiple FBG sensors 40, 41, 42 are provided on the expansion joint 20.

[0051] In the expansion joint according to the fourth embodiment, three protective tubes 37 and FBG sensors 40, 41, 42 are provided at equal intervals at the joint 28, but two protective tubes 37 and FBG sensors 40 and 41 may be provided at intervals, or four or more protective tubes 37 and FBG sensors may be provided at intervals. The intervals between the protective tubes 37 and the FBG sensors do not necessarily have to be equal. Furthermore, the protective tubes 37 and the FBG sensors 40, 41, 42 provided at the joint 28 may be introduced from the outside to the inside of the bellows material 23, or may be led from the inside to the outside.

[0052] Embodiment 5. Next, a description will be given of an expansion joint according to a fifth embodiment of the present invention. The expansion joint according to the fifth embodiment differs from the first embodiment in that the introduction path of the FBG sensor is filled with a sealing material. FIG. 13 is a schematic diagram showing a joint surface between the first end 28a and the second end 28b of the joint 28 of the bellows material 23 according to the fifth embodiment. A gap is formed between the first end 28a and the second end 28b and the protective tube 37 inserted in the region C of the joint 28 where the first end 28a and the second end 28b are not heat-fused. The gap is filled with a silicon sealant 60. By filling the gap with the silicon sealant 60, the gap between the protective tube 37 housing the FBG sensor 40 and the first end 28a and the second end 28b is blocked, and the airtightness of the bellows material 23 at the joint 28 can be improved. That is, the silicon sealant 60 constitutes a sealing member that improves the airtightness of the bellows material 23. The other configurations are the same as those of the first embodiment.

[0053] In this way, in the expansion joint according to the fifth embodiment, the silicone sealant 60 is filled between the joint 28 and the FBG sensor 40, thereby making it possible to further improve the airtightness between the joint 28 and the FBG sensor 40 and also to reduce vibrations transmitted to the FBG sensor 40.

[0054] In the fifth embodiment, a silicone sealant is used as a sealing material to fill the gap between the protective tube 37 and the first end 28a and the second end 28b, but the present invention is not limited to this. For example, other sealing materials such as a silylated acrylate-based sealing material may be used, or a cylindrical sealing material made of heat-resistant rubber may be used.

[0055] Embodiment 6 Next, a sixth embodiment of the present invention will be described. The expansion joint according to the sixth embodiment differs from the first embodiment in that a fluid pipeline is provided at the joint of the bellows material. 14 is a schematic perspective view of a bellows material of an expansion joint 20 according to the sixth embodiment. A protective tube 37 and an FBG sensor 40 arranged inside the protective tube 37 are introduced into the inside of the expansion joint 20 between a first end 28a and a second end 28b of a joint 28 of the bellows material 23.

[0056] Further, between the first end 28a and the second end 28b of the joint 28, a refrigerant pipe 71 is provided at a distance from the protective pipe 37 and the FBG sensor 40, and a refrigerant pipe 72 is provided at a distance from the refrigerant pipe 71. The refrigerant pipe 71 and the refrigerant pipe 72 are connected to a heat exchanger 63 provided outside the expansion joint 20, and form a fluid pipeline through which cooling water, which is a fluid, flows as a refrigerant, which is a heat medium.

[0057] FIG. 15 is a schematic diagram showing the joint surface between the first end 28a and the second end 28b of the joint 28 shown in FIG. 14. The joint surface between the first end 28a and the second end 28b has an area C1, an area C2, and an area C3 that are not thermally fused, which are provided in order at equal intervals. In an area B where the areas C1, C2, and C3 are not provided, the first end 28a and the second end 28b are integrated by thermal fusion. The area C1 is provided with a protective tube 37 and an FBG sensor 40 that are introduced from the outside to the inside of the expansion joint 20. The area C2 is provided with a refrigerant pipe 71 that is introduced from the outside to the inside of the expansion joint 20. The area C3 is provided with a refrigerant pipe 72 that is led from the inside to the outside of the expansion joint 20. The other configurations are the same as those of the first embodiment.

[0058] Next, the operation of the expansion joint 20 of the sixth embodiment will be described with reference to Fig. 14 and Fig. 15. During operation of the expansion joint 20, cooling water as a refrigerant sent from the heat exchanger 63 flows through the refrigerant pipe 71. The cooling water flows into the inside of the expansion joint 20, and flows through a cooling pipe (not shown) provided inside the expansion joint 20 to cool the bellows material 23. After that, the cooling water that has flowed through the cooling pipe flows through the refrigerant pipe 72 and flows out of the expansion joint 20, and after heat is dissipated in the heat exchanger 63, flows through the refrigerant pipe 71 and flows into the inside of the expansion joint 20. This makes it possible to efficiently cool the bellows material 23 of the expansion joint 20, and to suppress deterioration of the bellows material 23 due to heat.

[0059] In this way, the expansion joint 20 of the sixth embodiment has refrigerant pipes 71 and 72 through which a refrigerant can flow, and refrigerant pipe 71 is introduced from the outside of bellows material 23 to the inside of bellows material 23 via joint 28, and refrigerant pipe 72 is led from the inside of bellows material 23 to the outside of bellows material 23 via joint 28, so that the bellows material 23 of the expansion joint 20 can be efficiently cooled by the refrigerant flowing through refrigerant pipes 71 and 72.

[0060] In the sixth embodiment, cooling water is used as the refrigerant circulating through the refrigerant pipes 71 and 72, but a known refrigerant gas such as hydrofluorocarbon (HFC) may be used, or other types of liquid refrigerant may be used. Also, instead of the refrigerant pipes 71 and 72, a heat medium pipe may be provided in the expansion joint 20, and a heat medium of 150° C. or higher may be circulated through the bellows material 23 and the inner lower surface parts of the flanges 21 and 22 via the heat medium pipe. In this case, it is possible to suppress the generation of highly acidic drainage due to condensation, and to suppress corrosion of metal parts.

[0061] Furthermore, in the sixth embodiment, there is a configuration including refrigerant pipes 71 and 72, in which the refrigerant that flows through refrigerant pipe 71 and enters the inside of expansion joint 20 flows through a cooling pipe inside expansion joint 20, and the refrigerant flows from the cooling pipe through refrigerant pipe 72 and flows out to the outside of expansion joint 20; however, there may also be a configuration in which refrigerant pipe 71 is introduced into the inside of expansion joint 20, bellows material 23 is cooled by the refrigerant flowing through refrigerant pipe 71, and refrigerant pipe 71 is led out from the inside of expansion joint 20 to the outside of expansion joint 20.

[0062] In addition, in the first to sixth embodiments of the present invention, an FBG sensor is used as the sensor, but the present invention is not limited thereto, and any sensor such as a thermocouple or a temperature fuse may be used as appropriate. In addition, in the first to sixth embodiments of the present invention, the FBG sensor constituting the sensor itself is introduced and led out from the joint of the bellows material to the expansion joint, but a conducting wire, a signal wire, or the like connected to the sensor may be introduced and led out from the joint of the bellows material to the expansion joint.

[0063] In addition, in the first to sixth embodiments of the present invention, the protective tube 37 made of stainless steel is used, but instead of this, a protective tube made of another type of metal may be used, or a protective tube made of a resin such as PTFE, polyether ether ketone, polyphenylene sulfide, or heat-resistant silicone rubber may be used. Furthermore, in the first to sixth embodiments of the present invention, the protective tube 37 made of stainless steel is used, but if the environment inside the expansion joint 20 is an environment that can sufficiently withstand the use of the FBG sensor due to the strength and heat resistance of the FBG sensor itself, the FBG sensor may be introduced and led out from the joint of the bellows material without providing a protective tube.

[0064] Furthermore, in the first to sixth embodiments of the present invention, the FBG sensor is disposed radially outside the insulation section 30 and radially inside the bellows material 23, but the position at which the FBG sensor is disposed is not limited to this, and the FBG sensor may be disposed, for example, between adjacent insulation members, such as between the third insulation member 33 and the fourth insulation member 34, among the first insulation member 31, the second insulation member 32, the third insulation member 33, the fourth insulation member 34 and the fifth insulation member 35 that constitute the insulation section 30.

[0065] The components included in the first to sixth embodiments of the present invention and the components included in the variations thereof can be used in any suitable combination.

[0066] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0067] Various aspects of the present disclosure are summarized below as appendices.

[0068] (Appendix 1) An expansion joint that connects a first duct and a second duct through which a fluid flows, and through which the fluid flows, an outflow prevention part that is provided between the first duct and the second duct and has elasticity to prevent the outflow of the fluid; A sensor provided inside the outflow prevention portion; Equipped with The outflow prevention portion is formed in a cylindrical shape along a circumferential direction and has a joint portion between ends of the outflow prevention portion, The sensor is an expansion joint that is introduced from the outside of the outflow prevention part to the inside of the outflow prevention part via the joint of the outflow prevention part. (Appendix 2) The expansion joint described in Appendix 1, wherein the joint is formed by joining an inner surface of one end of the outflow prevention portion and an inner surface of the other end of the outflow prevention portion, and protrudes radially outward from the outflow prevention portion. (Appendix 3) The expansion joint described in Appendix 1 or 2, wherein the outflow prevention portion is formed by joining a plurality of outflow prevention members, and at least two of the joint portions are formed by joining ends of adjacent outflow prevention members among the plurality of outflow prevention members. (Appendix 4) An expansion joint as described in any one of appendix 1 to 3, wherein the sensor is led from the inside of the outflow prevention part to the outside of the outflow prevention part via at least one of the joints of the outflow prevention part. (Appendix 5) 5. The expansion joint according to claim 1, wherein a plurality of the sensors are provided adjacent to each other at the joint of the outflow prevention portion. (Appendix 6) 5. The expansion joint according to claim 1, wherein a plurality of the sensors are provided at intervals from each other at the joint of the outflow prevention section. (Appendix 7) 7. The expansion joint according to any one of claims 1 to 6, wherein a filler material is filled between the joint and the sensor. (Appendix 8) 8. The expansion joint according to any one of claims 1 to 7, further comprising a fluid pipeline therein through which a heat transfer medium can flow, the fluid pipeline being introduced from the outside of the outflow prevention part through the joint to the inside of the outflow prevention part, and being led from the inside of the outflow prevention part through the joint to the outside of the outflow prevention part. [Explanation of symbols]

[0069] 11 upstream duct (first duct), 12 downstream duct (second duct), 23 bellows material (flow prevention portion), 28 joint portion, 28a first end portion, 28b second end portion, 30 heat insulating portion, 37 protective tube (tubular protective member), 40 FBG sensor (sensor), 41 FBG sensor (sensor), 42 FBG sensor (sensor), 50 first bellows material, 51 second bellows material, 52 first joint portion, 52a first end portion, 52b second end portion, 53 second joint portion, 53a second end portion, 53b first end portion, 60 silicone sealant (filling member), 71 refrigerant pipe (fluid pipe), 72 refrigerant pipe (fluid pipe).

Claims

1. An expansion joint that connects a first duct and a second duct through which a fluid flows, and through which the fluid flows, an outflow prevention part that is provided between the first duct and the second duct, has elasticity, and prevents the outflow of the fluid; A sensor provided inside the outflow prevention portion; Equipped with The outflow prevention portion is formed in a cylindrical shape along a circumferential direction and has a joint portion between ends, The sensor is introduced from the outside of the outflow prevention part to the inside of the outflow prevention part via the joint of the outflow prevention part, The joint is an expansion joint formed by joining the inner surface of one end of the outflow prevention portion to the inner surface of the other end of the outflow prevention portion and protruding radially outward of the outflow prevention portion.

2. The expansion joint according to claim 1, wherein the outflow prevention portion is formed by joining a plurality of outflow prevention members, and at least two of the joint portions are formed by joining ends of adjacent outflow prevention members among the plurality of outflow prevention members.

3. The expansion joint according to claim 1 , wherein the sensor is led from an inside of the outflow prevention portion to an outside of the outflow prevention portion via at least one of the joints of the outflow prevention portion.

4. The expansion joint according to claim 1 , wherein a plurality of the sensors are provided adjacent to each other at the joint of the outflow prevention portion.

5. The expansion joint according to claim 1 , wherein a plurality of the sensors are provided at intervals from each other at the joint of the outflow prevention portion.

6. The expansion joint according to claim 1 , wherein a filler material is filled in a gap between the joint and the sensor.

7. 2. The expansion joint according to claim 1, further comprising a fluid pipeline through which a heat transfer medium can flow, the fluid pipeline being introduced from the outside of the outflow prevention part through the joint to the inside of the outflow prevention part and being led from the inside of the outflow prevention part through the joint to the outside of the outflow prevention part.

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