Expansion joint

Abstract

To provide an expansion joint that can suppress the deterioration of thermal insulation materials. [Solution] The expansion joint 20 connects an upstream duct 11 and a downstream duct 12 through which fluid flows, and includes a bellows material 23 that is provided between the upstream duct 11 and the downstream duct 12 and is expandable to prevent fluid leakage, an insulating member 31 provided inside the bellows material 23, and a flow passage 16 through which fluid flows. The insulating member 31 has a glass felt 40 and a PTFE sheet 43 covering the glass felt 40, so deterioration of the insulating member 31 can be suppressed.

Description

Technical Field

[0001] This invention relates to an expansion joint.

Background Art

[0002] An expansion joint is used at the connection part of ducts that transfer fluids such as high-temperature gases, which are provided in facilities such as thermal power plants and chemical plants, for the purpose of absorbing displacements, vibrations, stresses, etc. generated in the ducts themselves. As an example of a conventional expansion joint, for instance, the expansion joint described in Patent Document 1 is known. This expansion joint has a cylindrical non-metallic bellows material provided on the outermost part to prevent fluid outflow and having expansion and contraction flexibility, and a heat insulation member provided inside the bellows material and composed of glass fiber felt, and the fluid flows through the inside of the heat insulation member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the expansion joint described in Patent Document 1, a temperature difference occurs between the central part where high-temperature fluid flows and the outer peripheral part close to the outside air, and the high-temperature fluid may be cooled at the outer peripheral part of the expansion joint and cause condensation. Also, when the facility where this expansion joint is used stops operating, the temperature inside the expansion joint may drop due to the cessation of fluid flow and cause condensation. Furthermore, for the purpose of cleaning the duct when the facility stops, cleaning water may be flowed through the inside of this expansion joint. In such liquids containing the liquid generated by condensation or the remaining cleaning water, the heat insulation member provided on the lower side of the expansion joint is immersed for a long time, resulting in a decrease in the volume of the glass fiber felt of the heat insulation member, deterioration of the heat insulation performance and flexibility of the heat insulation member, or progress of the deterioration of the glass fiber felt contained in the heat insulation member due to the chemical components of the fluid dissolved in the liquid.

[0005] This invention was made to solve these problems and aims to provide an expansion joint that can suppress the deterioration of the heat insulating material caused by immersion of the heat insulating material in liquid that remains inside the expansion joint. [Means for solving the problem]

[0006] To solve the above problems, the expansion joint according to the present invention is an expansion joint that connects a first duct and a second duct through which a fluid flows, and through which the fluid flows, comprising: an outlet prevention part provided between the first duct and the second duct that is expandable and prevents the outflow of fluid; an internal member provided inside the outlet prevention part; and a flow passage provided inside the internal member through which the fluid flows, wherein the internal member comprises a fiber member and a waterproof member covering the fiber member.

[0007] Furthermore, the waterproofing member may cover the entire fiber member. Furthermore, the waterproofing member may cover a portion of the fiber member that is positioned below the expansion joint. Furthermore, the waterproofing member may cover the radially outer portion of the fiber member. Furthermore, the fibrous member may include a fibrous material formed from polytetrafluoroethylene. Furthermore, the spill prevention section and the internal components may be formed integrally. Furthermore, the fiber material may also be an insulating material. Furthermore, the fiber material may also be a dustproof material. Furthermore, the internal member may be a dent prevention member that prevents the expansion joint from collapsing when the flow passage becomes a negative pressure relative to the outside of the expansion joint. [Effects of the Invention]

[0008] The expansion joint according to the present invention comprises an internal member provided inside the spill-prevention section and a flow passage provided inside the internal member through which fluid flows. The internal member has a fiber member and a waterproof member covering the fiber member. Therefore, it is possible to suppress the deterioration of the heat insulating member caused by immersion of the heat insulating member by liquid stagnating inside the expansion joint. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a non-metallic expansion joint according to Embodiment 1. [Figure 2] Figure 1 shows a cross-sectional view of the upstream duct, downstream duct, and expansion joint. [Figure 3] Figure 2 is a schematic cross-sectional view of the first thermal insulation member. [Figure 4] This is a schematic cross-sectional view of the first heat insulating member provided in the expansion joint according to Embodiment 2. [Figure 5] Figure 4 is a schematic diagram of the first thermal insulation member as viewed along the axial direction. [Figure 6] This is a schematic diagram of the first heat insulating member, as viewed along the axial direction, according to a modified example of Embodiment 2. [Figure 7] This is a schematic cross-sectional view of the first heat insulating member provided in the expansion joint according to Embodiment 3. [Figure 8] This is a schematic cross-sectional view of the first heat insulating member provided in the expansion joint according to Embodiment 4. [Figure 9] This is a schematic cross-sectional view of the first heat insulating member provided in the expansion joint according to a modified example of Embodiment 4. [Figure 10] This is a schematic cross-sectional view of the first heat insulating member provided in the expansion joint according to Embodiment 5. [Figure 11] This is a cross-sectional view of the upstream duct, downstream duct, and expansion joint according to Embodiment 6. [Figure 12] This is a cross-sectional view of the upstream duct, downstream duct, and expansion joint according to Embodiment 7. [Modes for carrying out the invention]

[0010] Embodiment 1. The expansion joint according to Embodiment 1 of the present invention will be described below with reference to the attached drawings. Figure 1 is a schematic diagram of a non-metallic expansion joint according to Embodiment 1. In Embodiment 1, the duct structure 1 installed in a thermal power generation facility, etc., has a cylindrical upstream duct 11 and a downstream duct 12 through which a high-temperature fluid such as exhaust gas flows. The expansion joint 20, which is a non-metallic expansion joint provided in the duct structure 1, is positioned between the upstream duct 11 and the downstream duct 12 to connect the two ducts and prevent the outflow of the fluid inside. The expansion joint 20 also absorbs fluctuations in the distance between the two ducts due to expansion and contraction of the upstream duct 11 and the downstream duct 12, and absorbs vibrations generated in the upstream duct 11 and the downstream duct 12 due to the flow of fluid. Although the expansion joint 20 shown in Figure 1 is exemplified as being cylindrical, 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, for example, a rectangular 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 flange 21 and the flange 22 for hermetically connecting these flanges. The pair of flanges 21, 22 and the bellows material 23 are configured in a cylindrical shape to match the shapes of the cylindrical upstream duct 11 and downstream duct 12. A duct flange 14 is formed on the upstream duct 11, and the flange 21 is formed to correspond to the duct flange 14. By connecting (for example, fastening with bolts, etc.) the flange 21 and the duct flange 14, the expansion joint 20 and the upstream duct 11 are hermetically connected. A duct flange 15 is formed on the downstream duct 12, and the flange 22 is formed to correspond to the duct flange 15. By connecting (for example, fastening with bolts, etc.) the flange 22 and the duct flange 15, the expansion joint 20 and the downstream duct 12 are hermetically connected. Also, the flanges 21 and 22 can be formed of any metal such as stainless steel. The bellows material 23 has dimensions necessary for the distance between both ends of the expansion joint 20 (connection surfaces with the upstream duct 11 and the downstream duct 12) to be sufficiently longer than the separation distance between the connected upstream duct 11 and downstream duct 12. And by installing the expansion joint 20 between the upstream duct 11 and the downstream duct 12 with the bellows material 23 in a relaxed state, the thermal expansion, vibration, etc. of both ducts are absorbed.

[0012] FIG. 2 is a cross-sectional view of the upstream duct 11, the downstream duct 12, and the expansion joint 20 shown in FIG. 1. The arrow Y is an arrow indicating the upper side in the vertical direction. A baffle plate 13 is provided on the downstream side of the upstream duct 11 and is formed as a cylindrical body with a tip smaller than the inner diameter of the downstream duct 12. This baffle plate 13 can be formed of a metal such as stainless steel, for example. The inside of the baffle plate 13 is a flow passage 16 through which the fluid flows. The expansion joint 20 is arranged so as not to be directly exposed to the fluid flowing through the upstream duct 11 and passing through the flow passage 16 in the direction of arrow A due to the presence of the baffle plate 13.

[0013] The expansion joint 20 has a bellows material 23 disposed between the flange 21 and the flange 22 on the outermost side in the radial direction, and prevents the outflow of the fluid flowing through the upstream duct 11 and the downstream duct 12. The bellows material 23 is configured to have expansion and contraction flexibility along the outflow direction of the fluid indicated by the arrow A and the direction intersecting the outflow direction. Note that the bellows material 23 constitutes an expansion and contraction part.

[0014] The bellows material 23 is formed by laminating five layers of sheets, in order from the side closer to the flow passage 16, a sheet material of polytetrafluoroethylene (PTFE), a glass cloth, a sheet material of PTFE, a glass cloth, and a glass cloth. Note that the sheet structure of the bellows material 23 is an example, and the bellows material 23 can include any layer such as a seal layer for preventing the outflow of the fluid, a reinforcing layer for reinforcing the strength, and a protective layer for protecting the bellows material 23 from the surrounding environment such as outside air, moisture, and ultraviolet rays, and can be formed by appropriately adopting any known material such as PTFE, an inorganic fiber cloth such as a glass cloth, a metal fiber cloth, and a film-like resin. Further, the bellows material 23 can be composed of members having any number of layers.

[0015] The expansion joint 20 has a cylindrical heat insulating part 30 on the inner side in the radial direction of the bellows material 23, that is, on the fluid side closer to the flow passage 16. The heat insulating part 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 outer side in the radial direction, that is, on the outside air side. The heat insulating part 30 is composed of three layers of cylindrical heat insulating members, a first heat insulating member 31, a second heat insulating member 32, and a third heat insulating member 33, laminated in order from the outer side in the radial direction. The first heat insulating member 31, the second heat insulating member 32, and the third heat insulating member 33 constituting the heat insulating part 30 contain glass felt. The second heat insulating member 32 and the third heat insulating member 33 are fixed by a fixing bolt 34 penetrating the second heat insulating member 32 and the third heat insulating member 33. Note that the heat insulating part 30 has a function as a dent prevention member for preventing the expansion joint 20 from denting inward when the pressure in the flow passage 16 becomes a negative pressure state lower than the atmospheric pressure around the expansion joint 20.

[0016] Figure 3 is a schematic cross-sectional view of the first thermal insulation member 31 shown in Figure 2. Arrow Y indicates the vertical direction. The first thermal insulation member 31 comprises glass felt 40, which is a felt-like glass fiber material with thermal insulation properties; glass cloth 41, which is a cloth-like glass fiber material covering the glass felt 40; and wire mesh 42, which covers the glass cloth 41. Any metal such as stainless steel or Inconel steel wire can be used as the material for the wire mesh 42.

[0017] Furthermore, the first thermal insulation member 31 has a PTFE sheet 43 covering the wire mesh 42. That is, the entire first thermal insulation member 31, consisting of glass felt 40, glass cloth 41, and wire mesh 42, is wrapped by a waterproof PTFE sheet 43 provided on the outside of the wire mesh 42. In the schematic cross-sectional view of Figure 3, the thicknesses of the glass cloth 41, wire mesh 42, and PTFE sheet 43 are exaggerated relative to the dimensions of the glass felt 40 for the sake of explanation, but the actual thicknesses of the glass cloth 41, wire mesh 42, and PTFE sheet 43 are formed to be thinner than shown and are sufficiently thin relative to the dimensions of the glass felt 40. However, the thicknesses of the glass cloth 41, wire mesh 42, and PTFE sheet 43 may be determined as appropriate according to the need. Also, the first thermal insulation member 31 on the vertical upper side is shown as the first thermal insulation member 311, and the first thermal insulation member 31 on the vertical lower side is shown as the first thermal insulation member 312. The glass felt 40 constitutes the fibrous material, and the PTFE sheet 43 constitutes the waterproof material.

[0018] Next, the operation of the expansion joint 20 will be explained. When a high-temperature fluid flows through the flow passage 16 of the expansion joint 20 shown in Figure 2, the bellows material 23 is in contact with the low-temperature outside air relative to the high-temperature fluid. As a result, the fluid near the bellows material 23 may cool and liquefy, causing condensation. Also, when the equipment in which the duct structure 1 (see Figure 1), which uses the expansion joint 20, is installed is shut down, the temperature of the high-temperature fluid remaining inside the expansion joint 20 decreases, and the fluid may liquefy and condense. Furthermore, if the fluid flowing through the duct structure 1 is corrosive or easily contaminates the inside of the duct structure, cleaning water is circulated through the duct structure to clean the fluid when the equipment is shut down. However, this cleaning water may remain inside the expansion joint 20.

[0019] These condensed or residual cleaning water-containing liquids accumulate inside the lower part of the expansion joint 20. In particular, if the temperature on the radially outer side of the expansion joint 20 is sufficiently lower than the temperature on the radially inner side, or if the temperature inside the expansion joint 20 is low even before the equipment is put into operation, the amount of liquid lost by evaporation will be very small, making it easy for the liquid to accumulate inside the lower part of the expansion joint 20 for a long period of time.

[0020] As shown in Figure 3, the first heat insulating member 31 of this embodiment 1 is constructed by wrapping glass felt 40, glass cloth 41, and wire mesh 42 with a waterproof PTFE sheet 43 provided on the outside of the wire mesh 42. This prevents the glass felt 40, glass cloth 41, and wire mesh 42 from being immersed in the PTFE sheet 43 even if liquids containing condensation and residual cleaning water accumulate inside the lower part of the expansion joint 20.

[0021] In conventional expansion joints, condensation due to cooling of the bellows material, condensation due to liquefaction caused by a decrease in the temperature of the fluid flowing inside, or liquids including cleaning water in the duct structure can accumulate on the lower side of the expansion joint and penetrate the insulation material, which is made of inorganic fibers including glass felt or glass cloth and wire mesh, causing the insulation material to become immersed. This immersion in liquid reduces the volume of the glass felt in the insulation material, degrading its thermal insulation performance and flexibility. Furthermore, if the fluid flowing inside the expansion joint contains a large amount of acidic or alkaline components, the chemical components of the fluid dissolve, making the aforementioned liquid strongly acidic or strongly alkaline. This degrades and dissolves the inorganic fibers such as glass felt or glass cloth that make up the insulation material, and also degrades, corrodes, or dissolves the wire mesh provided on the outside of the inorganic fibers, resulting in damage to the insulation material. Furthermore, immersion of insulating materials in such liquids can lead to deterioration of the insulating performance and flexibility of the insulating materials, or damage, corrosion, or dissolution of the insulating materials, resulting in a deterioration of the insulating performance and flexibility of expansion joints containing insulating materials.

[0022] On the other hand, in the heat insulating member 31 provided on the radially outer side of the heat insulating section 30 of this embodiment 1, the entire glass felt 40, glass cloth 41, and wire mesh 42 are wrapped by a waterproof PTFE sheet 43. Therefore, in the expansion joint 20 of this embodiment 1, even if liquid including the condensation and residual cleaning water mentioned above accumulates inside the lower part of the expansion joint 20, the liquid will not come into contact with the glass felt 40, glass cloth 41, and wire mesh 42 of the heat insulating member 31. Furthermore, since the PTFE sheet 43 has acid and alkali resistance, it can maintain water resistance even if the liquid mentioned above is an acidic or alkaline liquid. Thus, because the heat insulating member 31 of this embodiment 1 is covered with a PTFE sheet 43, immersion of the heat insulating member 31 is prevented, and deterioration of the heat insulating performance and flexibility of the heat insulating member 31, or damage, corrosion, or dissolution of the heat insulating member 31, is prevented. This has the advantage of suppressing deterioration of the heat insulating member 31 and preventing deterioration of the performance of the expansion joint 20, such as heat insulating performance and flexibility.

[0023] Furthermore, the heat insulating member 31 is not provided with fixing bolts 34. Therefore, after the heat insulating member 31 is covered with the PTFE sheet 43, the PTFE sheet 43 will not be perforated by the fixing bolts 34, and the waterproofness of the PTFE sheet 43 is ensured.

[0024] As described above, the expansion joint 20 according to this embodiment 1 is an expansion joint 20 that connects an upstream duct 11 and a downstream duct 12 through which fluid flows, and through which fluid flows, and comprises a bellows material 23 provided between the upstream duct 11 and the downstream duct 12 that is expandable and prevents fluid leakage, a heat insulating member 31 provided inside the bellows material 23, and a flow passage 16 through which fluid flows, and the heat insulating member 31 has a glass felt 40 and a PTFE sheet 43 covering the glass felt 40, so that the glass felt 40 is not immersed in the liquid that remains inside the expansion joint 20 and deterioration of the heat insulating member 31 can be suppressed.

[0025] Furthermore, since the PTFE sheet 43 covers the entire glass felt 40, it is possible to reliably prevent the glass felt 40 from being immersed by the liquid that remains inside the expansion joint 20.

[0026] Furthermore, since the glass felt 40 is an insulating material, it can prevent heat from the fluid flowing through the flow passage 16 from being conducted to the bellows material 23.

[0027] Furthermore, the heat insulating section 30 is a dent prevention member that prevents the expansion joint 20 from denting when the flow passage 16 becomes negative pressure relative to the outside of the expansion joint 20. Therefore, it is possible to easily prevent the expansion joint 20 from denting when the flow passage 16 is under negative pressure.

[0028] In this embodiment 1, the first heat insulating member 31, which is arranged radially outward, was covered with a PTFE sheet 43. However, if the second heat insulating member 32 or the third heat insulating member 33 is not provided with fixing bolts 34, then the second heat insulating member 32 or the third heat insulating member 33 may also be covered with a PTFE sheet 43. Furthermore, in this embodiment 1, the heat insulating section 30 was formed by three layers of heat insulating members: the first heat insulating member 31, the second heat insulating member 32, and the third heat insulating member 33. However, the number of layers of heat insulating members constituting the heat insulating section 30 may be any other number.

[0029] Furthermore, although the duct structure 1 of this embodiment 1 was installed in a thermal power generation facility, it may also be installed in any other facility such as factory equipment or plant equipment.

[0030] Embodiment 2. Next, an expansion joint according to Embodiment 2 of the present invention will be described. In the following embodiments, the same reference numerals as those in Figures 1 to 3 indicate the same or similar components, so a detailed explanation of them will be omitted. The expansion joint according to Embodiment 2 is characterized in that the PTFE sheet is provided only on the vertically downward side compared to Embodiment 1. Figure 4 is a schematic cross-sectional view of the first thermal insulation member 31a provided in the expansion joint according to Embodiment 2. The cylindrical first thermal insulation member 31a is arranged on the radially outer side of the thermal insulation portion of the expansion joint. In Figure 4, the first thermal insulation member 31a on the vertically upper side is shown as the first thermal insulation member 311a, and the first thermal insulation member 31a on the vertically lower side is shown as the first thermal insulation member 312a.

[0031] In the lower vertical half of the first heat insulating member 31a, i.e., the portion shown as the first heat insulating member 312a, a PTFE sheet 43 is provided on the outside of the wire mesh 42, covering the glass felt 40, glass cloth 41, and wire mesh 42. On the other hand, in the upper vertical half of the first heat insulating member 31a, i.e., the portion shown as the first heat insulating member 311a, the PTFE sheet 43 is not provided on the outside of the wire mesh 42, and the glass felt 40, glass cloth 41, and wire mesh 42 are not covered. The other configurations are the same as in Embodiment 1.

[0032] Figure 5 is a schematic diagram of the cylindrical first heat insulating member 31a shown in Figure 4, viewed along the axial direction, i.e., the direction of fluid flow. The first heat insulating member 312a is covered by a PTFE sheet 43 wound around the vertical lower portion of the continuous annular section of the first heat insulating member 31a. As a result, there is a small gap between the PTFE sheet 43 and the first heat insulating member 312a, allowing ambient air to flow in and out between the PTFE sheet 43 and the first heat insulating member 312a through the edges of the PTFE sheet 43. This has the advantage that even if the PTFE sheet 43 comes into contact with a high-temperature fluid or a liquid containing high-temperature condensation and residual washing water, the air inside the PTFE sheet 43 will flow out from the edges of the PTFE sheet 43, preventing the PTFE sheet 43 from expanding.

[0033] Thus, in the expansion joint according to this second embodiment, since the PTFE sheet 43 covers a portion of the glass felt 40 that is disposed on the lower side of the expansion joint, only the portion of the glass felt 40 that is expected to be immersed by the liquid including condensation and residual cleaning water can be covered with the PTFE sheet 43. This reduces the amount of PTFE sheet 43 used in the manufacture of the expansion joint and reduces the parts cost required for manufacturing the expansion joint.

[0034] Next, a modified example of this second embodiment will be described. Figure 6 is a schematic diagram of the cylindrical first heat insulating member 31a shown in Figure 4, as viewed along the axial direction, i.e., the direction of fluid flow, according to a modified example of this second embodiment. The first heat insulating member 31a is formed separately from the first heat insulating member 312a, which is the lower half in the vertical direction, and the first heat insulating member 311a, which is the upper half. The lower portion, the first heat insulating member 312a, is wrapped and sealed with a PTFE sheet 43. This has the advantage that even if a large amount of liquid, including condensation and residual cleaning water, accumulates on the lower vertical side of the expansion joint 20, it is possible to reliably prevent the liquid from entering the first heat insulating member 312a.

[0035] In this embodiment 2 and its modified form, the PTFE sheet 43 covers the outside of the wire mesh 42 on the lower vertical half of the first heat insulating member 31a, but does not cover the outside of the wire mesh 42 on the upper vertical half of the first heat insulating member 31a. However, the embodiment is not limited to this, and the PTFE sheet 43 only needs to be provided on the lower vertical side of the first heat insulating member 31a in an area where immersion by liquids including the aforementioned condensation and residual cleaning water is expected to occur. For example, in the case of a cylindrical first heat insulating member 31a, the PTFE sheet 43 may cover the outside of the wire mesh 42 on the lower vertical side and for one-third of the diameter.

[0036] Embodiment 3. Next, an expansion joint according to Embodiment 3 of the present invention will be described. The expansion joint according to Embodiment 3 is characterized in that the PTFE sheet is provided only on the radially outward side compared to Embodiment 1. Figure 7 is a schematic cross-sectional view of the first thermal insulation member 31b provided in the expansion joint according to Embodiment 3. The cylindrical first thermal insulation member 31b is arranged radially outward of the thermal insulation portion of the expansion joint. In Figure 7, the first thermal insulation member 31b on the vertically upper side is shown as the first thermal insulation member 311b, and the first thermal insulation member 31b on the vertically lower side is shown as the first thermal insulation member 312b.

[0037] In the first heat insulating member 31b, the PTFE sheet 43 is provided only on the radially outer portion of the outside of the wire mesh 42. That is, the PTFE sheet 43 covers only the radially outer portion of the glass felt 40, glass cloth 41, and wire mesh 42 of the first heat insulating member 31b. The other configurations are the same as in Embodiment 1.

[0038] Expansion joints are generally formed in a cylindrical shape where it is difficult or impossible to distinguish the vertical direction. Therefore, when installing expansion joints in a duct structure provided in equipment, the vertical direction of the expansion joint may not be known or may not exist. In this embodiment 3, since the first heat insulating member 31b has a PTFE sheet 43 on its radially outer portion, even if the vertical direction of the expansion joint is not known or does not exist, only the portion where immersion by liquids including condensation and residual cleaning water is expected to occur can be covered with the PTFE sheet 43. This reduces the amount of PTFE sheet 43 used in the manufacture of the expansion joint and reduces the cost of parts required for manufacturing the expansion joint.

[0039] Thus, in the expansion joint according to this third embodiment, since the PTFE sheet 43 covers only the outer portion of the glass felt 40, the PTFE sheet 43 can cover only the portion of the glass felt 40 that is expected to be immersed in the liquid including condensation and residual cleaning water, as described above. This reduces the amount of PTFE sheet 43 used in the manufacture of the expansion joint and reduces the cost of parts required for manufacturing the expansion joint.

[0040] Note that the placement of the PTFE sheet 43 in this embodiment 3, as shown in Figure 7, is merely an example and is not limited thereto. The PTFE sheet 43 may cover only the radially outer portion of the first heat insulating member 31b, or it may cover the radially inner portion of the first heat insulating member 31b as well.

[0041] Embodiment 4. Next, an expansion joint according to Embodiment 4 of the present invention will be described. The expansion joint according to Embodiment 4 is provided with a gas permeable window in the PTFE sheet compared to Embodiment 1. Figure 8 is a schematic cross-sectional view of the first thermal insulation member 31c provided in the expansion joint according to Embodiment 4. The cylindrical first thermal insulation member 31c is arranged radially outward of the thermal insulation portion of the expansion joint. In Figure 8, the first thermal insulation member 31c on the vertically upper side is shown as the first thermal insulation member 311c, and the first thermal insulation member 31c on the vertically lower side is shown as the first thermal insulation member 312c.

[0042] The first insulation member 312c on the vertically lower side has a gas permeable window 44 formed in the PTFE sheet 43. The gas permeable window 44 is made of stretched polytetrafluoroethylene (ePTFE) material and has the property of being permeable to gases such as air but impermeable to liquids. In the configuration of glass felt 40, glass cloth 41 and wire mesh 42 covered with the PTFE sheet 43, the temperature difference between the inside and outside of the PTFE sheet 43 can cause the air inside to expand, which can cause the PTFE sheet 43 to expand and apply pressure to the structure surrounding the insulation member 31c. However, in this embodiment 3, since the PTFE sheet 43 is provided with a gas permeable window 44, the air that has expanded inside the PTFE sheet 43 can be released through the gas permeable window 44, preventing the PTFE sheet 43 from expanding. In addition, since the gas permeable window 44 does not allow liquids to pass through, the waterproofness of the PTFE sheet 43 is ensured.

[0043] The gas permeable window 44 can be placed at any position on the PTFE sheet 43, but in order to more effectively allow gas to permeate between the inside and outside of the PTFE sheet 43, it is preferable to place it at a height where liquids, including condensation and residual cleaning water inside the expansion joint described above, do not accumulate.

[0044] Thus, in this embodiment 4, the expansion joint has a gas permeable window 44 in the PTFE sheet 43 that prevents liquid permeation but allows gas to permeate. Therefore, while ensuring the waterproofness of the PTFE sheet 43, the air that expands inside the PTFE sheet 43 due to the temperature difference between the inside and outside of the PTFE sheet 43 is released through the gas permeable window 44, preventing the PTFE sheet 43 from expanding.

[0045] Figure 9 is a schematic cross-sectional view of a first thermal insulation member 31d provided in an expansion joint according to a modified example of Embodiment 4. In Embodiment 4, both the first thermal insulation member 311c on the vertical upper side and the first thermal insulation member 312c on the vertical lower side were covered with a PTFE sheet 43. However, as shown in Figure 9 of this modified example, in a configuration where the first thermal insulation member 311d on the vertical upper side is not covered with a PTFE sheet 43, and the first thermal insulation member 312c on the vertical lower side is covered with a PTFE sheet 43, a gas permeable window 44 may be provided in the PTFE sheet 43. This makes it possible to prevent the PTFE sheet 43 from expanding while ensuring the waterproofness of the PTFE sheet 43, even in a first thermal insulation member 31d where only the first thermal insulation member 312c on the vertical lower side is covered with a PTFE sheet 43.

[0046] In this embodiment 4 and its modified form, the gas permeable window 44 was formed of ePTFE material, but other materials may be used for the gas permeable window 44 as long as they are waterproof and gas permeable.

[0047] Furthermore, the first heat insulating member 31c of this embodiment 4 and the first heat insulating member 31d of the modified embodiment 4 may be configured such that a PTFE sheet 43 is wound around the vertical lower portion of a continuous annular section, as in embodiment 2, or the lower half and the upper half may be formed separately, with the lower portion being wrapped and sealed by the PTFE sheet 43, as in the modified embodiment 2.

[0048] Embodiment 5. Next, an expansion joint according to Embodiment 5 of the present invention will be described. The expansion joint according to Embodiment 5 uses a PTFE fiber material as the heat insulating member, compared to Embodiment 1. Figure 10 is a schematic cross-sectional view of the first thermal insulation member 31e provided in the expansion joint according to Embodiment 5. The cylindrical first thermal insulation member 31e is arranged radially outward of the thermal insulation portion of the expansion joint. In Figure 10, the first thermal insulation member 31e on the vertically upper side is shown as the first thermal insulation member 311e, and the first thermal insulation member 31e on the vertically lower side is shown as the first thermal insulation member 312e.

[0049] The first thermal insulation member 31e of Embodiment 5 has a felt-like PTFE fiber material 40a as the thermal insulation material, instead of the glass felt of Embodiment 1. The PTFE fiber material 40a has higher resistance to acids and alkalis than glass felt. Therefore, even if the PTFE sheet 43 is damaged and an acidic or alkaline liquid, such as the condensation and residual cleaning water mentioned above, flows into the inside, damage or corrosion of the PTFE fiber material 40a is suppressed, making it easier to maintain the thermal insulation properties of the first thermal insulation member 31e.

[0050] Thus, in this embodiment 5, since the fibrous member includes PTFE fiber material 40a, it is easier to maintain the thermal insulation properties of the first thermal insulation member 31e even if the PTFE sheet 43 is damaged.

[0051] Embodiment 6. Next, an expansion joint according to Embodiment 6 of the present invention will be described. Compared to Embodiment 1, the expansion joint according to Embodiment 6 is provided with an insulating member in the bellows material. Figure 11 is a cross-sectional view of the upstream duct 11, the downstream duct 12, and the expansion joint 20f according to this embodiment 6. The expansion joint 20f, which is a non-metallic expansion joint, connects the upstream duct 11 and the downstream duct 12 and prevents the leakage of fluid from inside. The expansion joint 20f is provided between flanges 21 and 22 and has a bellows material 23f that airtightly connects these flanges. The bellows material 23f houses an insulating section 30f inside. The radially inner side of the bellows material 23f is in contact with the baffle plate 13.

[0052] The heat-insulating section 30f comprises a heat-insulating member 34f made of glass felt, a glass cloth (not shown) provided on the outside of the heat-insulating member 34f, and a wire mesh (not shown) provided on the outside of the glass cloth on the radially inner side. The heat-insulating member 34f insulates the heat of the fluid flowing through the flow passage 16 and prevents the heat of the fluid from being directly transferred to the bellows material 23f provided on the radially outer side. Furthermore, a PTFE sheet 43 is provided on the outside of the glass cloth and wire mesh of the heat-insulating section 30f. That is, the heat-insulating member 34f, glass cloth and wire mesh are wrapped and covered by the PTFE sheet 43. This prevents the heat-insulating member 34f, glass cloth and wire mesh from being immersed in liquids containing condensation and residual cleaning water that remain inside the expansion joint 20f.

[0053] The heat insulating section 30f of this embodiment 6 functions as a dent prevention member that prevents the expansion joint 20f from collapsing inward when the pressure inside the flow passage 16 becomes a negative pressure state, which is lower than the atmospheric pressure around the expansion joint 20f. The other configurations are the same as in embodiment 1.

[0054] As described above, since the bellows material 23f and the heat insulating member 34f are formed integrally, even in a configuration where the heat insulating member 34f is provided on the bellows material 23f, the heat insulating member 34f can be covered with the PTFE sheet 43, similar to Embodiment 1, to suppress deterioration of the heat insulating member 34f.

[0055] Furthermore, the heat insulating section 30f or heat insulating member 34f in this embodiment 6 may function as a dustproof member to prevent dust from entering the flow passage 16 from outside the expansion joint 20f, or it may function as a vibration-damping member to suppress vibrations of the expansion joint 20f, or it may have both dustproof and vibration-damping functions.

[0056] Embodiment 7. Next, an expansion joint according to Embodiment 7 of the present invention will be described. The expansion joint according to Embodiment 7 is provided with a dustproof mat instead of an insulating section compared to Embodiment 1. Figure 12 is a cross-sectional view of the upstream duct 11, the downstream duct 12, and the expansion joint 20g according to this embodiment 7. The expansion joint 20g, which is a non-metallic expansion joint, connects the upstream duct 11 and the downstream duct 12 and prevents the leakage of fluid from inside. Inside the bellows material 23 of the expansion joint 20g, a dustproof mat 30g is provided to prevent dust from entering the flow passage 16 from the outside of the expansion joint 20g. The radially inner side of the dustproof mat 30g is in contact with the baffle plate 13.

[0057] The dustproof mat 30g comprises a fiber member 34g made of glass felt, a glass cloth (not shown) provided on the outside of the fiber member 34g, and a wire mesh (not shown) provided on the outside of the glass cloth. A PTFE sheet 43 is provided on the outside of the glass cloth and the wire mesh. That is, the fiber member 34g, the glass cloth, and the wire mesh are wrapped and covered by the PTFE sheet 43. This prevents the fiber member 34g, the glass cloth, and the wire mesh from being immersed in liquids containing condensation and residual cleaning water that remain inside the expansion joint 20g.

[0058] Furthermore, the dustproof mat 30g of this embodiment 7 functions as a dent prevention member that prevents the expansion joint 20g from collapsing inward when the pressure inside the flow passage 16 becomes a negative pressure state, which is lower than the atmospheric pressure around the expansion joint 20g. The other configurations are the same as in embodiment 1.

[0059] Thus, since the fiber member 34g is provided on the dustproof mat 30g, even in an expansion joint 20g having the dustproof mat 30g, the PTFE sheet 43 prevents the fiber member 34g of the dustproof mat 30g from being immersed in liquids containing condensation and residual cleaning water.

[0060] In Embodiment 7, a dustproof mat 30g was provided on the expansion joint 20g, but a vibration-damping mat may be provided to suppress vibrations of the expansion joint 20g, or a mat that has the functions of both a dustproof mat and a vibration-damping mat may be provided.

[0061] In embodiments 1 to 7 of the present invention, a PTFE sheet 43 was used as the waterproofing member, but the invention is not limited to this, and any sheet made of other waterproofing material may be used as the waterproofing member.

[0062] Furthermore, in Embodiments 1 to 4, the first heat insulating members 31a, 31b, 31c, and 31d are composed of a combination of glass felt 40, glass cloth 41, and wire mesh 42; in Embodiment 5, the first heat insulating member 31e is formed by a combination of PTFE fiber material 40a, glass cloth 41, and wire mesh 42; in Embodiment 6, the heat insulating section 30f is formed by a combination of a heat insulating member 34f made of glass felt, glass cloth, and wire mesh; and in Embodiment 7, the dustproof mat 30g is formed by a combination of glass felt, glass cloth, and wire mesh. However, the combinations of constituent materials for the heat insulating members and dustproof mats described in Embodiments 1 to 7 are merely examples, and any other configuration may be used. For example, any other type of inorganic fiber material may be used instead of the glass felt 40 in Embodiments 1 to 4, any other type of inorganic fiber material may be used instead of the glass felt heat insulating member 34f in Embodiment 6, and any other type of inorganic fiber material may be used for the dustproof mat in Embodiment 7.

[0063] Furthermore, the components included in Embodiments 1 to 7 of the present invention and the components included in their modified forms can be used in appropriate combinations.

[0064] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0065] The various aspects of this disclosure are summarized below as an appendix.

[0066] [Note 1] An expansion joint connecting a first duct and a second duct through which a fluid flows, with the fluid flowing through its interior, An outlet prevention section provided between the first duct and the second duct, which is expandable and prevents the outflow of the fluid, An internal member provided inside the aforementioned spill prevention section, A flow passage is provided inside the internal member through which the fluid flows. Equipped with, The aforementioned internal member is Fiber material and A waterproof member covering the aforementioned fiber member and An expansion joint having [Note 2] The waterproof member is an expansion joint as described in Appendix 1, which covers the entire fiber member. [Note 3] The waterproof member covers a portion of the fiber member that is disposed below the expansion joint, as described in Appendix 1. [Note 4] The waterproof member is an expansion joint as described in Appendix 1, which covers the radially outer portion of the fiber member. [Note 5] The waterproof member is an expansion joint according to any one of the appendices 1 to 4, having a gas permeable portion that prevents liquid permeation and allows gas to permeate. [Note 6] The fibrous member is an expansion joint according to any one of the appendices 1 to 5, comprising a fibrous material formed of polytetrafluoroethylene. [Note 7] An expansion joint according to any one of the appendices 1 to 6, wherein the spill prevention portion and the internal member are formed integrally. [Note 8] The fiber member is an expansion joint as described in any one of the appendices 1 to 7, which is an insulating member. [Note 9] The fiber member is a dustproof member, and is an expansion joint as described in any one of the appendices 1 to 7. [Note 10] The expansion joint according to any one of the appendices 1 to 9, wherein the internal member is a dent prevention member that prevents the expansion joint from denting when the flow passage becomes a negative pressure relative to the outside of the expansion joint. [Explanation of Symbols]

[0067] 16 Flow passage, 23, 23f Bellows material (outflow prevention part), 30, 30f Insulation part (internal material, dent prevention material), 30g Dustproof mat (dustproof material), 31, 31a, 31b, 31c, 31d, 31e First insulation material, 34f Insulation material, 34g Fiber material (dustproof material), 40 Glass felt (insulation material), 43 PTFE sheet (waterproof material), 44 Gas permeable window (gas permeable part).

Claims

1. An expansion joint connecting a first duct and a second duct through which a fluid flows, the fluid flowing through the inside of the joint, An outlet prevention section is provided between the first duct and the second duct, which is expandable and expandable and prevents the outflow of the fluid, An internal member provided inside the aforementioned spill prevention section, A flow passage is provided inside the internal member through which the fluid flows. Equipped with, The aforementioned internal member is Fiber material and A waterproof member covering the aforementioned fiber member and An expansion joint having

2. The expansion joint according to claim 1, wherein the waterproof member covers the entire fiber member.

3. The expansion joint according to claim 1, wherein the waterproof member covers a portion of the fiber member that is disposed below the expansion joint.

4. The expansion joint according to claim 1, wherein the waterproof member covers the radially outer portion of the fiber member.

5. The waterproof member has a gas permeable portion that prevents liquid permeation and allows gas to permeate, as described in any one of claims 1 to 4.

6. The expansion joint according to any one of claims 1 to 4, wherein the fiber member comprises a fiber material formed of polytetrafluoroethylene.

7. The expansion joint according to any one of claims 1 to 4, wherein the spill prevention portion and the internal member are formed integrally.

8. The expansion joint according to any one of claims 1 to 4, wherein the fiber member is a heat insulating member.

9. The expansion joint according to any one of claims 1 to 4, wherein the fiber member is a dustproof member.

10. The expansion joint according to any one of claims 1 to 4, wherein the internal member is a dent prevention member that prevents the expansion joint from denting when the flow passage becomes a negative pressure relative to the outside of the expansion joint.

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