A bend pressure balanced bellows expansion joint

Abstract

This invention provides a bend-type pressure-balanced bellows expansion joint, comprising a first bend, a connecting pipe, and a second bend. One end of the first bend is connected to the first end of the connecting pipe, and the other end is connected to one end of a first working bellows to form a first pipeline. One end of the second bend is connected to the second end of the connecting pipe, and the other end is connected to one end of the second working bellows to form a second pipeline. The first pipeline is positioned above the second pipeline. The vertical distance from the central axis of the first working bellows to the center of the connecting pipe is A, and the effective area of ​​the first working bellows is Ag1. The vertical distance from the central axis of the second working bellows to the center of the connecting pipe is B, and the effective area of ​​the second working bellows is Ag2, where A × Ag1 = B × Ag2. The first working bellows being positioned above the second working bellows reduces the required length of the bend-type pressure-balanced expansion joint. By satisfying A × Ag1 = B × Ag2, the torque at both ends of the connecting pipe is balanced when the expansion joint is filled with a pressure medium, thus achieving balanced pressure thrust.

Description

Technical Field

[0001] This invention relates to the field of bellows expansion joint technology, and in particular to a bend pressure-balanced bellows expansion joint. Background Technology

[0002] Corrugated pipe expansion joints are pipeline compensation components widely used in power, petrochemical, heating, steel, and urban construction industries. They are used to compensate for positional shifts in pipeline systems or equipment caused by temperature differences or mechanical movement, and to eliminate vibrations, through axial expansion and contraction or angular changes in connections between equipment and pipelines in power or heating networks.

[0003] Commonly used bend pressure balanced bellows expansion joint structures, such as Figure 1 As shown, it includes a working end 31, a large tie rod 33, an elbow assembly 34, and a guide rod 35. Along the length direction, a working bellows 32 and a balancing bellows 36 are respectively installed on both sides of the elbow assembly 34, resulting in a relatively large required dimension in the length direction. For spaces with limited length, the arrangement of this bellows expansion joint is difficult, hindering its widespread use. Summary of the Invention

[0004] In view of this, the present invention aims to propose a bend-pressure balanced bellows expansion joint to solve the problems of the large required length dimension and limited application scenarios of existing bend-pressure balanced bellows expansion joints.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A bend-pressure balanced bellows expansion joint includes a first bend, a connecting pipe, and a second bend. One end of the first bend is connected to the first end of the connecting pipe, and the other end of the first bend is connected to one end of a first working bellows to form a first pipeline. One end of the second bend is connected to the second end of the connecting pipe, and the other end of the second bend is connected to one end of the second working bellows to form a second pipeline. The first pipeline is located above the second pipeline. The vertical distance from the center axis of the first working bellows to the center of the connecting pipe is A, the effective area of ​​the first working bellows is Ag1, the vertical distance from the center axis of the second working bellows to the center of the connecting pipe is B, the effective area of ​​the second working bellows is Ag2, and A×Ag1=B×Ag2. By adding a first elbow and a second elbow at each end of the connecting pipe, the first working bellows is positioned above the second working bellows, meaning the first and second working bellows are parallel. This reduces the length required for traditional elbow pressure-balanced expansion joints. Furthermore, by satisfying the relationship A×Ag1=B×Ag2, the torque at both ends of the connecting pipe is balanced when the expansion joint is filled with a medium at pressure p, thus balancing the pressure thrust and solving the displacement compensation problem for pipelines with limited length.

[0007] Furthermore, the other end of the first working bellows is connected to the first end pipe, and the other end of the second working bellows is connected to the second end pipe. The medium enters the expansion joint through the first end pipe, passes through the first working bellows, the first elbow, the connecting pipe, the second elbow, and the second working bellows in sequence, and then flows out from the second end pipe.

[0008] Furthermore, the bend pressure-balanced bellows expansion joint includes a first hinge plate, a second hinge plate, and a fifth hinge plate. The outer side of the first end pipe is connected to a first vertical plate, and the first vertical plate and the first hinge plate are hinged together. The outer side of the second end pipe is connected to a second vertical plate, and the second vertical plate and the second hinge plate are hinged together. The first hinge plate is disposed on the outside of the first working bellows and has a gap with the first working bellows. The second hinge plate is disposed on the outside of the second working bellows and has a gap with the second working bellows. The upper end of the fifth hinge plate is connected to the end of the first hinge plate away from the first end pipe, and the lower end of the fifth hinge plate is connected to the end of the second hinge plate away from the second end pipe.

[0009] Furthermore, the fifth hinge plate is provided with an upper through hole, a middle through hole, and a lower through hole from top to bottom. The middle through hole is located in the middle of the fifth hinge plate. The first hinge plate is provided with a corresponding first through hole, and the axes of the first through hole and the upper through hole coincide. A first pin passes through the first through hole and the upper through hole to realize the hinged connection between the first hinge plate and the fifth hinge plate. The second hinge plate is provided with a corresponding second through hole, and the axes of the second through hole and the lower through hole coincide. A second pin passes through the second through hole and the lower through hole to realize the hinged connection between the second hinge plate and the fifth hinge plate.

[0010] Furthermore, the fifth hinge plate is connected by a bracket and a connecting pipe. One end of the bracket is connected to the outer wall of the connecting pipe, and the other end passes through the central through hole and the bracket via a fifth pin, thus realizing the hinged connection between the fifth hinge plate and the bracket. The bracket not only provides stable support and positioning for the fifth hinge plate, but also allows the fifth hinge plate and the bracket to rotate relative to each other.

[0011] Furthermore, the first pipeline connects multiple working bellows in series, with each working bellows having an equal effective area Ag1. Similarly, the second pipeline connects multiple working bellows in series, with each working bellows having an equal effective area Ag2. By connecting multiple working bellows with equal effective areas in the same pipeline, the needs of different application scenarios can be met, allowing the pipeline to have greater expansion and contraction space during thermal expansion, and ensuring torque balance at both ends of the connecting pipe, thus achieving balanced pressure thrust.

[0012] Furthermore, the first pipeline includes a first working bellows and a third working bellows connected in series, the effective areas of the first working bellows and the third working bellows being equal; the second pipeline includes a second working bellows and a fourth working bellows connected in series, the effective areas of the second working bellows and the fourth working bellows being equal.

[0013] Furthermore, the first pipeline includes a first connecting pipe, one end of which is connected to a first working bellows, and the other end of which is connected to a third working bellows. The second pipeline includes a second connecting pipe, one end of which is connected to a second working bellows, and the other end of which is connected to a fourth working bellows. The first connecting pipe is used to achieve a series connection between the first and third working bellows, and the second connecting pipe is used to achieve a series connection between the second and fourth working bellows.

[0014] Furthermore, a third hinge plate is provided on the outer side of the first connecting pipe. One end of the first hinge plate is connected to the first vertical plate, and the other end of the first hinge plate is hinged to the third hinge plate. A fourth hinge plate is provided on the outer side of the second connecting pipe. One end of the second hinge plate is connected to the second vertical plate, and the other end of the second hinge plate is hinged to the fourth hinge plate. Providing multiple hinge mechanisms on both sides of the connecting pipe helps compensate for deformation and displacement in the pipeline system, allowing stress to be more dispersed on the bellows expansion joint, reducing damage or fatigue caused by stress concentration.

[0015] Furthermore, a sealing plate is provided at the end of the second end pipe away from the second working bellows to close the second end pipe. The connecting pipe is a tee, including a first opening, a second opening, and a third opening. The first opening is connected to a first pipeline, the second opening is connected to a second pipeline, and the third opening is connected to the outside. The medium enters through the first end pipe and fills the bend-pipe pressure-balanced bellows expansion joint, and then flows out from the third opening. The pressure thrust is balanced at the first opening and the second opening.

[0016] Compared with the prior art, the bend pressure-balanced bellows expansion joint of the present invention has the following advantages:

[0017] (1) While reducing the length required by the traditional bend pressure balance expansion joint, it ensures that the torque at both ends of the connecting pipe is balanced when the expansion joint is filled with pressure medium, thereby achieving balanced pressure thrust and solving the displacement compensation problem of pipelines with limited length direction.

[0018] (2) Multiple hinge mechanisms are set on both sides of the connecting pipe, which is beneficial to compensate for deformation and displacement in the pipeline system, so that the stress is more dispersed on the bellows expansion joint, reducing damage or fatigue caused by stress concentration.

[0019] (3) By connecting multiple working bellows with equal effective area in series on the same pipeline, the needs of different application scenarios can be met, so that the pipeline has a larger expansion and contraction space when thermally expanding, and the torque balance at both ends of the connecting pipe can be ensured to achieve balanced pressure thrust. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of a pressure-balanced bellows expansion joint for bends in existing technology.

[0022] Figure 2 This is a schematic diagram of a bend pressure-balanced bellows expansion joint structure according to Embodiment 1 of the present invention;

[0023] Figure 3 for Figure 2 View at point C;

[0024] Figure 4 This is a schematic diagram of a bend pressure-balanced bellows expansion joint structure according to Embodiment 2 of the present invention;

[0025] Figure 5 A schematic diagram of a bend pressure-balanced bellows expansion joint structure according to Embodiment 3 of the present invention;

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. First end pipe; 2. First vertical plate; 3. First working bellows; 4. First hinge plate; 5. First elbow; 6. First pin; 7. Fifth hinge plate; 8. Fifth pin; 9. Connecting pipe; 10. Second end pipe; 11. Second vertical plate; 12. Second working bellows; 13. Second hinge plate; 14. Second pin; 15. Second elbow; 16. Support; 17. Third working bellows; 18. Fourth working bellows; 19. First connecting pipe; 20. Second connecting pipe; 21. Sealing plate; 22. Third hinge plate; 23. Fourth hinge plate; 24. Third pin; 25. Fourth pin; 31. Working end; 32. Working bellows; 33. Large tie rod; 34. Elbow assembly; 35. Guide rod; 36. Balance bellows. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The embodiments described herein are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] It should be noted that the terms "upper," "lower," "left," "right," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Example 1

[0031] like Figures 2-3As shown, a bend-pressure balanced corrugated pipe expansion joint of the present invention includes a first bend 5, a connecting pipe 9, and a second bend 15. One end of the first bend 5 is connected to the first end of the connecting pipe 9, and the other end of the first bend 5 is connected to one end of the first working corrugated pipe 3 to form a first pipeline. One end of the second bend 15 is connected to the second end of the connecting pipe 9, and the other end of the second bend 15 is connected to one end of the second working corrugated pipe 12 to form a second pipeline. The first pipeline is disposed on the upper side of the second pipeline. The vertical distance from the central axis of the first working corrugated pipe 3 to the center of the connecting pipe 9 is A, and the effective area of ​​the first working corrugated pipe 3 is Ag1. The vertical distance from the central axis of the second working corrugated pipe 12 to the center of the connecting pipe 9 is B, and the effective area of ​​the second working corrugated pipe 12 is Ag2. A×Ag1=B×Ag2. By adding a first elbow 5 and a second elbow 15 to both ends of the connecting pipe 9, the first working bellows 3 is positioned above the second working bellows 12, i.e., the first working bellows 3 and the second working bellows 12 are parallel. This reduces the length required for a traditional bend-type pressure-balanced expansion joint. At the same time, by satisfying the following relationship A×Ag1=B×Ag2, it ensures that when the expansion joint is filled with a medium with pressure p, the torque at both ends of the connecting pipe 9 is balanced, thus achieving balanced pressure thrust and solving the displacement compensation problem of pipelines with limited length direction.

[0032] The other end of the first working bellows 3 is connected to the first end pipe 1, and the other end of the second working bellows 12 is connected to the second end pipe 10. The medium enters the expansion joint through the first end pipe 1, passes through the first working bellows 3, the first elbow 5, the connecting pipe 9, the second elbow 15, and the second working bellows 12 in sequence, and then flows out from the second end pipe 10.

[0033] The bend-pipe pressure-balanced bellows expansion joint includes a first hinge plate 4, a second hinge plate 13, and a fifth hinge plate 7. The outer side of the first end pipe 1 is connected to a first vertical plate 2, and the first vertical plate 2 and the first hinge plate 4 are hinged together. The outer side of the second end pipe 10 is connected to a second vertical plate 11, and the second vertical plate 11 and the second hinge plate 13 are hinged together. The first hinge plate 4 is located outside the first working bellows 3 and has a gap with it. The second hinge plate 13 is located outside the second working bellows 12 and has a gap with it. The upper end of the fifth hinge plate 7 is connected to the end of the first hinge plate 4 away from the first end pipe 1, and the lower end of the fifth hinge plate 7 is connected to the end of the second hinge plate 13 away from the second end pipe 10. The first hinge plate 4 and the fifth hinge plate 7 are hinged together and can rotate relative to each other. The second hinge plate 13 and the fifth hinge plate 7 are also hinged together and can rotate relative to each other.

[0034] Furthermore, the fifth hinge plate 7 is provided with an upper through hole, a middle through hole, and a lower through hole from top to bottom. The middle through hole is located in the middle of the fifth hinge plate 7. The first hinge plate 4 is provided with a corresponding first through hole. The axes of the first through hole and the upper through hole coincide. A first pin 6 passes through the first through hole and the upper through hole to achieve a hinged connection between the first hinge plate 4 and the fifth hinge plate 7. The second hinge plate 13 is provided with a corresponding second through hole. The axes of the second through hole and the lower through hole coincide. A second pin 14 passes through the second through hole and the lower through hole to achieve a hinged connection between the second hinge plate 13 and the fifth hinge plate 7.

[0035] The fifth hinge plate 7 is connected to the connecting pipe 9 via a bracket 16. One end of the bracket 16 is connected to the outer wall of the connecting pipe 9, and the other end passes through the central through hole and the bracket 16 via a fifth pin 8, thus achieving a hinged connection between the fifth hinge plate 7 and the bracket 16. By setting the bracket 16, not only can the fifth hinge plate 7 be stably supported and positioned, but the fifth hinge plate 7 and the bracket 16 also form a hinged relationship, allowing them to rotate relative to each other.

[0036] In the installed state, the center lines of the first hinge plate 4 and the second hinge plate 13 are parallel and located in the same plane. The center line of the first hinge plate 4 is perpendicular to the center line of the fifth hinge plate 7, and the center line of the second hinge plate 13 is perpendicular to the center line of the fifth hinge plate 7. The distance A between the upper through hole and the middle through hole is denoted as A, and the distance B between the lower through hole and the middle through hole is denoted as B. This invention has multiple hinge mechanisms. At the upper end of the central hole, the first hinge plate 4 and the first vertical plate 2 form a hinge mechanism, and the first hinge plate 4 and the fifth hinge plate 7 form a hinge mechanism. At the lower end of the central hole, the second hinge plate 13 and the second vertical plate 11 form a hinge mechanism, and the second hinge plate 13 and the fifth hinge plate 7 form a hinge mechanism. These multiple hinge mechanisms allow the bellows expansion joint to deform with a certain degree of freedom when subjected to axial, lateral, or angular displacement, thereby compensating for deformation and displacement in the pipeline system. At the same time, it better disperses stress on the bellows expansion joint, reducing damage or fatigue caused by stress concentration.

[0037] Example 2

[0038] Based on Embodiment 1, the first pipeline connects multiple working bellows in series, with each working bellows having an equal effective area Ag1. Similarly, the second pipeline connects multiple working bellows in series, with each working bellows having an equal effective area Ag2. By connecting multiple working bellows with equal effective areas in the same pipeline, the needs of different application scenarios can be met, allowing the pipeline to have greater expansion and contraction space during thermal expansion, and ensuring torque balance at both ends of the connecting pipe 9, thus achieving balanced pressure thrust.

[0039] Specifically, regarding this application Figure 4In the first pipeline, there are a first working bellows 3 and a third working bellows 17 connected in series, with the effective areas of the first working bellows 3 and the third working bellows 17 being equal. The second pipeline includes a second working bellows 12 and a fourth working bellows 18 connected in series, with the effective areas of the second working bellows 12 and the fourth working bellows 18 being equal.

[0040] Furthermore, the first pipeline includes a first connecting pipe 19, one end of which is connected to the first working bellows 3, and the other end of which is connected to the third working bellows 17. The second pipeline includes a second connecting pipe 20, one end of which is connected to the second working bellows 12, and the other end of which is connected to the fourth working bellows 18. The first connecting pipe 19 is used to connect the first working bellows 3 and the third working bellows 17 in series, and the second connecting pipe 20 is used to connect the second working bellows 12 and the fourth working bellows 18 in series.

[0041] The third working corrugated pipe 17 is connected to the first elbow 5. The first working corrugated pipe 3, the first connecting pipe 19, the third working corrugated pipe 17 and the first elbow 5 are connected in series to form a first pipeline. The fourth working corrugated pipe 18 is connected to the second elbow 15. The second working corrugated pipe 12, the second connecting pipe 20, the fourth working corrugated pipe 18 and the second elbow 15 are connected in series to form a second pipeline.

[0042] A third hinge plate 22 is provided on the outer side of the first connecting pipe 19. One end of the first hinge plate 4 is connected to the first vertical plate 2, and the other end of the first hinge plate 4 is hinged to the third hinge plate 22. A fourth hinge plate 23 is provided on the outer side of the second connecting pipe 20. One end of the second hinge plate 13 is connected to the second vertical plate 11, and the other end of the second hinge plate 13 is hinged to the fourth hinge plate 23. The first hinge plate 4 and the third hinge plate 22 are connected together and are located on the outer side of the first pipe, with a gap between them. The second hinge plate 13 and the fourth hinge plate 23 are connected together and are located on the outer side of the second pipe, with a gap between them. Furthermore, the first hinge plate 4 and the third hinge plate 22 are hinged by a third pin 24, and the second hinge plate 13 and the fourth hinge plate 23 are hinged by a fourth pin 25. For the third hinge plate 22, one end is hinged to the first hinge plate 4 and the other end is hinged to the fifth hinge plate 7. For the fourth hinge plate 23, one end is hinged to the second hinge plate 13 and the other end is hinged to the fifth hinge plate 7. Multiple hinge mechanisms are set on both sides of the connecting pipe 9, which is beneficial to compensate for deformation and displacement in the pipeline system, so that the stress is more dispersed on the bellows expansion joint and the damage or fatigue caused by stress concentration is reduced.

[0043] The bend pressure-balanced bellows expansion joint of the present invention significantly reduces the length dimension requirements while increasing the number of working bellows, and can meet the requirements of pressure bearing, compensation for axial and radial displacement, and balancing pressure thrust, thus solving the problem of displacement compensation in pipelines with limited length.

[0044] Example 3

[0045] Based on Example 1 or Example 2, such as Figure 5 As shown, a sealing plate 21 is provided at the end of the second end pipe 10 away from the second working bellows 12 to close the second end pipe 10. The connecting pipe 9 is a tee and includes a first opening, a second opening, and a third opening. The first opening is connected to the first pipeline, the second opening is connected to the second pipeline, and the third opening is connected to the outside. The medium enters through the first end pipe 1 and fills the bend pressure-balanced bellows expansion joint, and then flows out from the third opening. The pressure thrust is balanced at the first opening and the second opening.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bend-pressure balanced bellows expansion joint, characterized in that, Includes a first elbow (5), a connecting pipe (9), and a second elbow (15). One end of the first elbow (5) is connected to the first end of the connecting pipe (9), and the other end of the first elbow (5) is connected to one end of the first working corrugated pipe (3) to form a first pipeline. One end of the second elbow (15) is connected to the second end of the connecting pipe (9), and the other end of the second elbow (15) is connected to one end of the second working corrugated pipe (12) to form a second pipeline. The first pipeline is located on the upper side of the second pipeline. The vertical distance from the center axis of the first working corrugated pipe (3) to the center of the connecting pipe (9) is A, and the effective area of ​​the first working corrugated pipe (3) is Ag1. The vertical distance from the center axis of the second working corrugated pipe (12) to the center of the connecting pipe (9) is B, and the effective area of ​​the second working corrugated pipe (12) is Ag2. A×Ag1=B×Ag2. The other end of the first working bellows (3) is connected to the first end pipe (1), and the other end of the second working bellows (12) is connected to the second end pipe (10). The bend pressure balance type bellows expansion joint includes a first hinge plate (4), a second hinge plate (13), and a fifth hinge plate (7). The outer side of the first end pipe (1) is connected to the first vertical plate (2), and the first vertical plate (2) and the first hinge plate (4) are hinged together. The outer side of the second end pipe (10) is connected to the second vertical plate (11), and the second vertical plate (11) and the second hinge plate (13) are hinged together. The first hinge plate (4) is located on the outside of the first working bellows (3) and has a gap with the first working bellows (3). The second hinge plate (13) is located on the outside of the second working bellows (12) and has a gap with the second working bellows (12). The fifth hinge plate (7) The upper end of the hinge plate (7) is connected to the end of the first hinge plate (4) away from the first end tube (1), and the lower end of the fifth hinge plate (7) is connected to the end of the second hinge plate (13) away from the second end tube (10). The fifth hinge plate (7) is provided with an upper through hole, a middle through hole and a lower through hole from top to bottom. The middle through hole is located in the middle of the fifth hinge plate (7). The first hinge plate (4) is provided with a first through hole. The axes of the first through hole and the upper through hole coincide. The first pin (6) passes through the first through hole and the upper through hole to realize the hinge connection between the first hinge plate (4) and the fifth hinge plate (7). The second hinge plate (13) is provided with a second through hole. The axes of the second through hole and the lower through hole coincide. The second pin (14) passes through the second through hole and the lower through hole to realize the hinge connection between the second hinge plate (13) and the fifth hinge plate (7).

2. The bend-pressure balanced bellows expansion joint according to claim 1, characterized in that, The fifth hinge plate (7) is connected to the bracket (16) and the connecting pipe (9). One end of the bracket (16) is connected to the outer wall of the connecting pipe (9), and the other end passes through the central through hole and the bracket (16) through the fifth pin (8) to realize the hinge connection between the fifth hinge plate (7) and the bracket (16).

3. The bend-pressure balanced bellows expansion joint according to claim 1, characterized in that, The first pipeline has multiple working bellows connected in series, and the effective area Ag1 of each working bellows on the first pipeline is equal. The second pipeline has multiple working bellows connected in series, and the effective area Ag2 of each working bellows on the second pipeline is equal.

4. The bend-pressure balanced bellows expansion joint according to claim 3, characterized in that, The first pipeline includes a first working bellows (3) and a third working bellows (17) connected in series, with the effective areas of the first working bellows (3) and the third working bellows (17) being equal. The second pipeline includes a second working bellows (12) and a fourth working bellows (18) connected in series, with the effective areas of the second working bellows (12) and the fourth working bellows (18) being equal.

5. The bend-pressure balanced bellows expansion joint according to claim 3, characterized in that, The first pipeline includes a first connecting pipe (19), one end of which is connected to a first working corrugated pipe (3) and the other end is connected to a third working corrugated pipe (17). The second pipeline includes a second connecting pipe (20), one end of which is connected to a second working corrugated pipe (12) and the other end is connected to a fourth working corrugated pipe (18).

6. The bend-pressure balanced bellows expansion joint according to claim 5, characterized in that, A third hinge plate (22) is provided on the outside of the first connecting pipe (19). One end of the first hinge plate (4) is connected to the first upright plate (2), and the other end of the first hinge plate (4) is hinged to the third hinge plate (22). A fourth hinge plate (23) is provided on the outside of the second connecting pipe (20). One end of the second hinge plate (13) is connected to the second upright plate (11), and the other end of the second hinge plate (13) is hinged to the fourth hinge plate (23).

7. The bend-pressure balanced bellows expansion joint according to claim 1, characterized in that, A sealing plate (21) is provided at the end of the second end pipe (10) away from the second working corrugated pipe (12) to seal the second end pipe (10). The connecting pipe (9) is a tee and includes a first opening, a second opening and a third opening. The first opening is connected to the first pipeline, the second opening is connected to the second pipeline, and the third opening is connected to the outside.

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