High-temperature corrosion-resistant corrugated pipe expansion joint for liquid metal environment
By designing a high-temperature corrosion-resistant bellows expansion joint and utilizing a combination of limiting components and an inner sleeve, the corrosion problem of bellows in a liquid metal environment was solved, achieving corrosion resistance and flexible connection of the bellows and extending its service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-28
- Publication Date
- 2026-03-13
AI Technical Summary
Existing bellows expansion joints are prone to corrosion and failure in high-temperature, high-density, and corrosive liquid metal environments, especially the problem of internal flow corrosion has not been effectively solved.
Design a high-temperature corrosion-resistant bellows expansion joint for liquid metal environments, including a bellows, a limiting component, and an inner sleeve. The limiting component restricts the deformation of the bellows, and the inner sleeve isolates the flow channel to prevent dynamic corrosion and convert it into static corrosion.
It extends the service life of the bellows, prevents plastic deformation and dynamic corrosion, and maintains the safe and stable operation of the experimental device.
Smart Images
Figure CN223992053U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of corrugated pipe technology, and in particular to a high-temperature corrosion-resistant corrugated pipe expansion joint for use in liquid metal environments. Background Technology
[0002] Liquid metal has been selected as a coolant material for fourth-generation fast reactors due to its high density and high corrosivity. Currently, the thermal-hydraulic properties of liquid metal in experimental and energy fields are still under research. Therefore, designing and constructing high-temperature liquid metal experimental devices is an indispensable research method. Maintaining stress balance in the piping system and ensuring reasonable release of local deformation displacement in high-flow-rate, high-temperature liquid metal experimental devices, and achieving safe and stable operation of the device, requires the use of bellows expansion joints. However, the bellows in these joints must maintain flexible deformation properties, resulting in very thin walls. Long-term operation in highly corrosive liquid metal media poses a risk of corrosion failure.
[0003] Existing bellows expansion joints primarily operate on water and gas, making them unsuitable for high-temperature, high-density, and corrosive liquid heavy metal environments. Furthermore, existing corrosion protection measures for bellows expansion joints mainly target joints and external corrosion, lacking specific design solutions for internal flow corrosion. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a high-temperature corrosion-resistant corrugated pipe expansion joint for use in liquid metal environments.
[0005] The technical solution adopted by this utility model to solve its technical problem is: a high-temperature corrosion-resistant corrugated pipe expansion joint for use in liquid metal environments, used on the main body of a pipe, comprising:
[0006] A corrugated pipe whose two ends are respectively connected to the ports of the main body of the pipe;
[0007] A limiting component is connected to the outer wall of the pipe body at both ends. The limiting component is located outside the bellows to limit the deformation margin of the bellows.
[0008] An inner sleeve is connected to the inner wall of the main pipe body at both ends. The inner sleeve is a telescopic structure, and the entire length of the inner sleeve isolates the corrugated pipe from the internal flow channel of the main pipe body.
[0009] In some embodiments, the inner sleeve includes a first suspension sleeve and a second suspension sleeve, wherein the first suspension sleeve and the second suspension sleeve are disposed opposite to each other and are clearance-fitted.
[0010] In some embodiments, the first suspension sleeve sequentially includes a first docking section, a first isolation section, and a first connecting section welded and fixed to the pipe body, wherein the first docking section and the first isolation section are respectively disposed opposite to the corrugated pipe;
[0011] The second suspension sleeve includes a second docking section, a second isolation section, and a second connecting section welded and fixed to the main body of the pipe. The second docking section and the second isolation section are arranged opposite to the corrugated pipe, and the second docking section is axially clearance-fitted with the first docking section.
[0012] In some embodiments, an axial gap is provided between the first mating section and the second isolation section, and an axial gap is provided between the second mating section and the first isolation section.
[0013] In some embodiments, the first connecting section is provided with at least one first overflow port, the first overflow port extending axially along the pipe body and communicating with the internal flow channel of the pipe body and the static chamber between the inner sleeve and the bellows;
[0014] The second connecting section is provided with at least one second overflow port, which extends axially along the pipe body and connects the internal flow channel of the pipe body and the static chamber between the inner sleeve and the bellows.
[0015] In some embodiments, the limiting assembly includes a first limiting plate, a second limiting plate, and at least four limiting rods, wherein the four limiting rods are symmetrically arranged, and each limiting rod is respectively connected and fixed to the first limiting plate and the second limiting plate.
[0016] In some embodiments, the limiting component further includes a plurality of reinforcing ribs welded and fixed to the main body of the pipe, the reinforcing ribs being welded and fixed to the outer side of the first limiting plate and / or the second limiting plate away from the corrugated pipe.
[0017] In some embodiments, the high-temperature corrosion-resistant bellows expansion joint further includes an outer sleeve, which is disposed on the outer periphery of the bellows;
[0018] The outer sleeve is connected and fixed to the first limiting plate, and a gap is left between it and the second limiting plate; or the outer sleeve is connected and fixed to the second limiting plate, and a gap is left between it and the first limiting plate.
[0019] In some embodiments, the high-temperature corrosion-resistant corrugated pipe expansion joint further includes a heat tracing wire, which is installed on the outer sleeve and close to the corrugated pipe.
[0020] In some embodiments, the corrugated pipe is made of 31608 stainless steel or a high-entropy corrosion-resistant alloy. By implementing this invention, the following beneficial effects are achieved:
[0021] This utility model discloses a high-temperature corrosion-resistant corrugated expansion joint for liquid metal environments, used on a pipeline body. It includes: a corrugated pipe with both ends connected to the ports of the pipeline body; a limiting component with both ends connected to the outer wall of the pipeline body, the limiting component being located outside the corrugated pipe to limit its deformation margin; and an inner sleeve with both ends connected to the inner wall of the pipeline body, the inner sleeve being a telescopic structure and its entire length isolating the corrugated pipe from the internal flow channel of the pipeline body. The limiting component restricts the deformation margin of the corrugated pipe, preventing plastic deformation. The inner sleeve isolates the corrugated pipe from the internal flow channel of the pipeline body, preventing the corrugated pipe from being subjected to dynamic scouring corrosion by the liquid metal medium, changing the dynamic scouring corrosion of the corrugated pipe to static corrosion, thus extending the service life of the corrugated pipe. The limiting component restricts the deformation margin of the corrugated pipe, preventing plastic deformation. By isolating the bellows from the internal flow channel of the main pipe body through the inner sleeve, the bellows is prevented from being dynamically eroded and corroded by liquid metal media. This changes the dynamic erosion corrosion of the bellows to static corrosion, which can extend the service life of the bellows. Attached Figure Description
[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:
[0023] Figure 1 This is a schematic diagram of the structure of a high-temperature corrosion-resistant bellows expansion joint according to an embodiment of the present invention;
[0024] Figure 2 yes Figure 1 A cross-sectional view along the AA direction;
[0025] Figure 3 yes Figure 1 Cross-sectional view along the BB direction;
[0026] Figure 4 yes Figure 1 Enlarged section view of the middle part;
[0027] Figure 5 yes Figure 3 An enlarged schematic diagram of the D-structure. Detailed Implementation
[0028] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0029] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0030] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a chemical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0032] See Figures 1 to 5 One embodiment of this utility model discloses a high-temperature corrosion-resistant corrugated expansion joint for use in liquid metal environments, applied to the pipe body 1. This high-temperature corrosion-resistant corrugated expansion joint is designed for use in experimental devices involving high-temperature, high-density, and corrosive liquid metals. It is corrosion-resistant, high-temperature resistant, and increases pipe flexibility within a limited space. It provides flexible pipe connections in metal medium experimental devices, eliminating the impact of deformation and displacement caused by changes in mass, temperature, etc., which could lead to unstable circuit operation. It also addresses the contradiction between the corrosiveness of the metal medium and the thin wall thickness of the corrugated pipe 2. The pipe body 1 refers to the pipe in the experimental device circuit where the corrugated expansion joint needs to be installed; the wall thickness and nominal dimensions of this pipe serve as the installation boundary for the corrugated pipe 2. The liquid metal environment can refer to a high-temperature, high-flow-rate lead-bismuth metal medium. Understandably, this high-temperature corrosion-resistant corrugated expansion joint can also be used in ordinary environments, such as environments where the working medium is water or gas.
[0033] like Figure 1As shown, the high-temperature corrosion-resistant bellows expansion joint includes a bellows 2, a limiting component 3, and an inner sleeve 4. The bellows 2 is used to maintain the stress balance of the piping system and to reasonably release local deformation displacement, ensuring the safe and stable operation of the experimental device. Both ends of the bellows 2 are connected to the ports of the main pipe body 1, for example, by welding or through flanges, depending on the installation requirements. The bellows 2 is the flexible structure in this high-temperature corrosion-resistant bellows expansion joint. The material selected is based on the operating temperature and pressure of the liquid metal medium, such as lead-bismuth fluid, in the experimental device. When the liquid metal temperature is below 300℃, a bellows 2 made of 31608 stainless steel can be used; if the liquid metal operating temperature is between 300℃ and 600℃, a high-entropy corrosion-resistant alloy or a material containing such an alloy coating can be selected to prevent the bellows 2 structure from failing due to operating temperature.
[0034] The two ends of the limiting component 3 are connected to the outer wall of the pipe body 1, for example, by welding. The limiting component 3 is located on the outside of the bellows 2 to limit the deformation margin of the bellows 2 and prevent the bellows 2 from undergoing plastic deformation. The limiting component 3 is used to enhance the rigidity of the bellows 2, resist the bending stress on the bellows 2, and maintain the shape of the bellows 2 to avoid excessive deformation. The limiting component 3 can be made of a material with the same or similar coefficient of thermal expansion and strength as the material of the pipe body 1.
[0035] The inner sleeve 4 is connected to the inner wall of the pipe body 1 at both ends. The inner sleeve 4 is a telescopic structure, and its entire length isolates the bellows 2 from the internal flow channel of the pipe body 1, preventing direct erosion and corrosion of the bellows 2 by the liquid metal medium. The inner sleeve 4 encloses the bellows 2 with a sufficiently small gap between itself and the inner wall of the bellows 2, forming a static chamber. When the bellows 2 deforms, the inner sleeve 4 deforms along with it. Because the inner sleeve 4 is telescopic, its deformation response to the bellows 2 is its internal expansion and contraction.
[0036] This high-temperature corrosion-resistant corrugated expansion joint can solve the problem of absorbing local deformation and displacement of the piping system in the experimental device. At the same time, the mechanical structure of the corrugated pipe 2 part has been reasonably modified to maintain the flexibility of the corrugated pipe 2 and avoid corrosion failure caused by the direct long-term scouring of the corrugated pipe 2 by liquid metal.
[0037] In some embodiments, such as Figure 4As shown, the inner sleeve 4 includes a first suspension sleeve 41 and a second suspension sleeve 42, which are arranged opposite to each other with a clearance fit. The inner sleeve 4 encloses the bellows 2, and the gap between the inner sleeve 4 and the inner wall of the bellows 2 is sufficiently small, forming a static chamber between the inner sleeve 4 and the inner wall of the bellows 2. When the bellows 2 deforms, the inner sleeve 4 will deform along with the bellows 2, that is, the first suspension sleeve 41 and the second suspension sleeve 42 will shrink, expand, or undergo other deformations relative to each other. By forming a static chamber between the bellows 2 and the inner sleeve 4, the flow-induced scouring corrosion of the bellows 2 by the liquid metal medium is transformed into static corrosion, preventing the high-temperature, high-flow-rate liquid metal medium inside the pipeline body 1 from directly scouring the bellows 2 and reducing the corrosion rate.
[0038] In some embodiments, the first suspension sleeve 41 sequentially includes a first mating section 411, a first insulating section 412, and a first connecting section 413 welded and fixed to the pipe body 1. The first mating section 411 and the first insulating section 412 are respectively disposed opposite to the bellows 2. The second suspension sleeve 42 sequentially includes a second mating section 421, a second insulating section 422, and a second connecting section 423 welded and fixed to the pipe body 1. The second mating section 421 and the second insulating section 422 are disposed opposite to the bellows 2, and the second mating section 421 and the first mating section 411 are axially clearance fitted. The first connecting section 413 and the second connecting section 423 are used for welding and fixing to the pipe body 1. For example, the first connecting section 413 is welded and fixed to the inner wall of the pipe body 1 at the upper part of the bellows 2, avoiding the weld joint between the upper part of the bellows 2 and the pipe body 1; the second connecting section 423 is welded and fixed to the inner wall of the pipe body 1 at the lower part of the bellows 2, avoiding the weld joint between the lower part of the bellows 2 and the pipe body 1. The first isolation section 412 and the second isolation section 422 serve as the main structure for isolating liquid metal, maintaining a sufficiently small gap with the bellows 2. The first mating section 411 and the second mating section 421 are clearance fits to ensure that, under deformations comparable to those of the bellows 2, the internal flow channels of the bellows 2 and the main pipe body 1 remain isolated.
[0039] In some embodiments, an axial gap is provided between the first mating section 411 and the second insulating section 422, and an axial gap is provided between the second mating section 421 and the first insulating section 412. The inner sleeve 4 can move with the deformation of the bellows 2, ensuring the bellows 2's ability to deform with the thermal expansion and contraction of the pipe. That is, the axial gaps between the first mating section 411 and the second insulating section 422, and between the second mating section 421 and the first insulating section 412, can prevent the deformation and movement of the first and second suspension sleeves 41 and 42. The material of this structure is required to be consistent with the material of the bellows 2, and the backflow inner sleeve 4 is required to maintain a sufficiently small gap with the bellows 2. Understandably, a gap can be provided between the first mating section 411 and the second mating section 421 to ensure that the relative movement of the first mating section 411 and the second mating section 421 is not affected by mutual friction forces.
[0040] In some embodiments, such as 2 and Figure 5 As shown, the first connecting section 413 is provided with at least one first overflow port, which extends axially along the pipe body 1 and connects the internal flow channel of the pipe body 1 and the static chamber between the inner sleeve 4 and the bellows 2. The second connecting section 423 is provided with at least one second overflow port 424, which extends axially along the pipe body 1 and connects the internal flow channel of the pipe body 1 and the static chamber between the inner sleeve 4 and the bellows 2. Due to the gap between the first connecting section 411 and the second connecting section 421, some liquid metal medium flows into the static chamber between the bellows 2 and the inner sleeve 4, and can flow out through the overflow port into the internal flow channel of the pipe body 1, preventing long-term static solidification and affecting the normal operation of the bellows 2. Several overflow ports can be provided along the circumference of the first connecting section 413, such as two, three, or four. When the number of overflow ports is two or more, the overflow ports are symmetrically arranged along the circumference of the first connecting section 413. Similarly, several overflow ports can be provided along the circumference of the second connecting section 423, such as two, three, four, etc. When the number of overflow ports is two or more, the overflow ports are symmetrically arranged along the circumference of the first connecting section 413. Understandably, in some other embodiments, the overflow ports provided on the first connecting section 413 and the overflow ports provided on the second connecting section 423 can correspond one-to-one, and the line connecting the two corresponding overflow ports is parallel to the axial direction of the pipe body 1. The first overflow port is not shown in the figure, but can be referred to... Figure 3 and Figure 5 The structure of the second overflow port 424.
[0041] Understandably, when using this utility model, if the bellows expansion joint is placed horizontally, a certain tilt angle needs to be set for the bellows expansion joint to facilitate the discharge of most liquid metal media.
[0042] In some embodiments, such as Figure 1As shown, the limiting assembly 3 includes a first limiting plate 31, a second limiting plate 32, and at least four limiting rods 33. The four limiting rods 33 are symmetrically arranged, and each limiting rod 33 is connected and fixed to the first limiting plate 31 and the second limiting plate 32 respectively. The limiting rods are used to enhance the stiffness and resistance to bending stress of the bellows 2, while limiting the maximum deformation of the bellows 2. That is, the limiting rods 33 can increase the pipe strength at the bellows 2 section and provide limitation for the deformation of the bellows 2. Some or all of the limiting rods 33 are screws. Each limiting rod 33 can be connected and fixed to the first limiting plate 31 by two bolts and to the second limiting plate 32 by two nuts. The limiting rods 33 are detachably connected to the first limiting plate 31 and the second limiting plate 32, and the installation position of the limiting rods 33 can be set according to the length of the bellows 2. The first limiting plate 31 and the second limiting plate 32 can be limiting rings or multiple limiting plates arranged symmetrically.
[0043] In some embodiments, the limiting component 3 further includes a plurality of reinforcing ribs 34 welded and fixed to the pipe body 1. The reinforcing ribs 34 are welded and fixed to the outer side of the first limiting plate 31 and / or the second limiting plate 32 away from the corrugated pipe 2. The number of reinforcing ribs 34 can be one, two, or more. For example, multiple reinforcing ribs 34 may be symmetrically arranged, each reinforcing rib 34 being welded and fixed to the outer side of the first limiting plate 31 away from the corrugated pipe 2 and also welded and fixed to the pipe body 1; or multiple reinforcing ribs 34 may be symmetrically arranged, each reinforcing rib 34 being welded and fixed to the outer side of the second limiting plate 32 away from the corrugated pipe 2 and also welded and fixed to the pipe body 1.
[0044] In some embodiments, the high-temperature corrosion-resistant bellows expansion joint further includes an outer sleeve 5, which is disposed on the outer periphery of the bellows 2. The outer sleeve 5 is connected and fixed to the first limiting plate 31, and a gap is left between it and the second limiting plate 32; or the outer sleeve 5 is connected and fixed to the second limiting plate 32, and a gap is left between it and the first limiting plate 31. At least one end of the outer sleeve 5 is in a free state to prevent affecting the deformation of the bellows 2. The gap between the bellows 2 and the outer sleeve 5 is maintained sufficiently small to provide a foundation for installing the heating structure without affecting the deformation of the bellows 2.
[0045] In some embodiments, to achieve the purpose of heating to prevent solidification, the high-temperature corrosion-resistant bellows expansion joint further includes a heating structure installed on the outer sleeve 5 and close to the bellows 2, for indirect preheating of the bellows 2. For example, the heating structure is a heat tracing wire, which is installed on the outer sleeve 5 and close to the bellows 2. This can provide a temperature environment for the filling of liquid metal media, preheating the bellows to a specified temperature before injecting the liquid metal media, thus preventing the liquid metal from solidifying and clogging the pipe. The heat tracing wire is not shown in the diagram.
[0046] By implementing this utility model, the following beneficial effects can be achieved:
[0047] This invention relates to a high-temperature corrosion-resistant bellows expansion joint for use in liquid metal environments. The limiting component 3 restricts the deformation margin of the bellows 2, preventing plastic deformation. The inner sleeve 4 isolates the bellows 2 from the internal flow channel of the pipe body 1, preventing dynamic scouring corrosion of the bellows 2 by the liquid metal medium. This changes the dynamic scouring corrosion of the bellows 2 to static corrosion, thus extending its service life.
[0048] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, without departing from the concept of the present utility model, the above embodiments or technical features can be freely combined, and several modifications and improvements can be made. These all fall within the protection scope of the present utility model, that is, the embodiments described "in some embodiments" can be freely combined with any of the embodiments above and below. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.
Claims
1. A high temperature corrosion resistant bellows expansion joint for use in liquid metal environments for use on a pipe body (1) characterised in that, The utility model relates to a kind of pipe structures, including: Corrugated pipe (2) is connected with the port of the pipeline body (1) respectively at both ends; Limiting component (3) is connected with the outer wall of the pipeline body (1) respectively at both ends, the limiting component (3) is located at the outside of the corrugated pipe (2) to limit the transformation margin of the corrugated pipe (2); Inner sleeve (4) is connected with the inner wall of the pipeline body (1) respectively at both ends, the inner sleeve (4) is telescopic structure, and the inner sleeve (4) full length separates the internal flow passage of the corrugated pipe (2) and the pipeline body (1), prevent corrugated pipe from being subjected to liquid metal medium dynamic scouring corrosion; The inner sleeve (4) includes first suspension sleeve (41) and second suspension sleeve (42), the first suspension sleeve (41) is oppositely arranged with the second suspension sleeve (42) and gap fits; Static chamber is formed between the inner sleeve (4) and the inner wall of the corrugated pipe (2); The corrugated pipe (2) is made of 31608 stainless steel material or high-entropy corrosion-resistant alloy.
2. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 1, wherein, The first suspension sleeve (41) includes first docking section (411), first insulation section (412) and first connecting section (413) welded fixed with the pipeline body (1) in sequence, the first docking section (411) and the first insulation section (412) are oppositely arranged with the corrugated pipe (2) respectively; The second suspension sleeve (42) includes second docking section (421), second insulation section (422) and second connecting section (423) welded fixed with the pipeline body (1) in sequence, the second docking section (421) and the second insulation section (422) are oppositely arranged with the corrugated pipe (2), and the second docking section (421) and the first docking section (411) are axially gap fitted.
3. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 2, wherein, There is axial gap between the first docking section (411) and the second insulation section (422), and there is axial gap between the second docking section (421) and the first insulation section (412).
4. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 2, wherein, The first connecting section (413) is provided with at least one first overflow port, and the first overflow port extends along the axial direction of the pipeline body (1) and communicates the internal flow passage of the pipeline body (1) with the static chamber between the inner sleeve (4) and the corrugated pipe (2); The second connecting section (423) is provided with at least one second overflow port (424), and the second overflow port (424) extends along the axial direction of the pipeline body (1) and communicates the internal flow passage of the pipeline body (1) with the static chamber between the inner sleeve (4) and the corrugated pipe (2).
5. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 1, wherein, The limiting component (3) includes first limiting plate (31), second limiting plate (32) and at least four limiting rods (33), four limiting rods (33) are symmetrically arranged, and each limiting rod (33) is connected and fixed with the first limiting plate (31) and the second limiting plate (32) respectively.
6. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 5, wherein, The limiting assembly (3) further comprises a plurality of reinforcing ribs (34) welded to the pipeline body (1), and the reinforcing ribs (34) are welded to the outer side of the first limiting plate (31) and / or the second limiting plate (32) away from the bellows (2).
7. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 5, wherein, The high-temperature corrosion-resistant bellows expansion joint further comprises an outer sleeve (5) arranged on the outer periphery of the bellows (2). The outer sleeve (5) is connected and fixed with the first limiting plate (31) and has a gap with the second limiting plate (32); or the outer sleeve (5) is connected and fixed with the second limiting plate (32) and has a gap with the first limiting plate (31).
8. The high temperature corrosion resistant bellows expansion joint for liquid metal environments of claim 7, wherein, The high-temperature corrosion-resistant bellows expansion joint further comprises a heat tracing wire installed on the outer sleeve (5) and close to the bellows (2).