A constrained expansion joint for straight pipe section compensation

Abstract

The present invention provides a constrained expansion joint for straight pipe section compensation, which includes at least three deformation units. An end pipe is connected to the end of the first deformation unit. A ring plate is arranged on the circumferential outer side of the end pipe. A universal ring is arranged on the circumferential outer side of the bellows of the first deformation unit. The first deformation unit further includes a first universal hinge plate, which is arranged parallel to the axial direction. One end of the first universal hinge plate is connected to the ring plate, and the other end of the first universal hinge plate is connected to the universal ring through a first pin shaft. The first deformation unit and the second deformation unit are connected through an intermediate pipe. The first deformation unit and the second deformation unit are mirror-symmetrical. The universal ring of the first deformation unit and the universal ring of the second deformation unit are connected through a second universal hinge plate, and the second universal hinge plate is arranged parallel to the axial direction of the expansion joint. It can compensate for the axial, transverse, and angular displacements of the straight pipe section, has a small external dimension, is suitable for flexible compensation of high-pressure pipelines in narrow spaces, reduces pipeline stress, and reduces the forces on the brackets and equipment nozzles.

Description

Technical Field

[0001] The present invention relates to the field of metal bellows expansion joints, and more particularly, to a restraint type expansion joint for straight pipe section compensation. Background Art

[0002] For high-pressure straight pipe sections, restraint type expansion joints that can restrain the pressure thrust of the bellows are generally selected for compensation, which can reduce the forces on the pipe supports and equipment nozzles. The existing restraint type expansion joints selected for high-pressure straight pipe sections mainly include: straight pipe pressure balance type expansion joints, a combination of 3 single hinge type expansion joints, external pressure straight pipe pressure balance type expansion joints, bypass straight pipe pressure balance type expansion joints, and composite straight pipe balance type expansion joints. Among them, the straight pipe pressure balance type expansion joints, external pressure straight pipe pressure balance type expansion joints, and composite straight pipe balance type expansion joints have large external dimensions, about 2 times the pipe diameter, occupy a large space, and this type of expansion joint has a large weight and high stiffness, and the pipe supports or equipment connected to it are subjected to large forces during compensation. The combination of 3 single hinge type expansion joints is only suitable for compensation of long straight pipe sections, occupies a large space, and requires the setting of guide supports. The bypass straight pipe pressure balance type expansion joints also have relatively large external dimensions, about 2 times the pipe diameter, occupy a large space, have a large weight of the expansion joint, and are only limited to the compensation of straight pipe sections with low flow rates and relatively low requirements for pressure drop. Thus, the existing expansion joint structures cannot effectively meet the requirements for straight pipe section compensation and application environments that are demanding for the self-weight, external dimensions, and stiffness of the expansion joints. Summary of the Invention

[0003] In view of this, the present invention aims to provide a restraint type expansion joint for straight pipe section compensation to solve the problem that the existing expansion joint structures cannot effectively meet the requirements for straight pipe section compensation that are demanding for the self-weight, external dimensions, and stiffness of the expansion joints in the prior art.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows:

[0005] A constrained expansion joint for straight pipe section compensation, comprising at least 3 deformation units. The first deformation unit, the second deformation unit and the third deformation unit are sequentially connected along the axial direction of the expansion joint. An end pipe is connected to the end of the first deformation unit. A ring plate is arranged on the circumferential outer side of the end pipe. A universal ring is arranged on the circumferential outer side of the bellows of the first deformation unit. The first deformation unit further includes a first universal hinge plate. The first universal hinge plate is arranged parallel to the axial direction of the expansion joint. One end of the first universal hinge plate is connected to the ring plate. The other end of the first universal hinge plate is connected to the universal ring through a first pin shaft. The first deformation unit and the second deformation unit are connected through an intermediate pipe. The first deformation unit and the second deformation unit are mirror-symmetrical. The universal ring of the first deformation unit and the universal ring of the second deformation unit are connected through a second universal hinge plate. The second universal hinge plate is arranged parallel to the axial direction of the expansion joint.

[0006] Further, an intermediate ring plate is arranged on the circumferential outer side of the intermediate pipe. The intermediate ring plate is used to fix the second universal hinge plate.

[0007] Further, first limiting plates are arranged on both the universal ring of the first deformation unit and the universal ring of the second deformation unit. Both ends of the second universal hinge plate are connected to the first limiting plates through second pin shafts.

[0008] Further, the expansion joint comprises 5 deformation units. Taking the midpoint in the axial direction as the center, both ends of the expansion joint are symmetrical. Both ends of the third deformation unit are connected to the second deformation units.

[0009] Further, a first single hinge plate and a second single hinge plate are arranged on the circumferential outer side of the third deformation unit. One end of the first single hinge plate is connected to one end of the second single hinge plate through a third pin shaft. The other end of the first single hinge plate is connected to the ring plate of the second deformation unit. The other end of the second single hinge plate is connected to the ring plate of the other second deformation unit.

[0010] Further, a second limiting plate is further arranged between the first single hinge plate and the second single hinge plate. The second limiting plate is used to limit the rotation angle of the first single hinge plate and the second single hinge plate.

[0011] Further, when the constrained expansion joint only compensates for axial displacement, during installation, angular pre-displacements of θ = 0.5 - 1° are pre-performed on the deformation units at both ends of the expansion joint.

[0012] Further, the bellows is selected as a reinforced U-shaped bellows. The reinforced U-shaped bellows is provided with a reinforcing ring at the wave trough of the bellows.

[0013] Further, two first universal hinge plates are connected to the same first pin shaft, and the two first universal hinge plates are respectively located on the inner and outer sides of the universal ring.

[0014] Further, the first universal hinge plate is welded to the ring plate.

[0015] Compared with the prior art, the restraint type expansion joint for straight pipe section compensation of the present invention has the following advantages:

[0016] When the straight pipe section where the expansion joint is located and the connected equipment need to be compensated by the expansion joint due to thermal expansion caused by temperature rise, each deformation unit of the expansion joint rotates around the pin shaft, and through the appropriate angular deformation of the corrugated pipe, the center line between two adjacent deformation units becomes a broken line relative to the initial axis, and the combination of broken lines in different directions realizes the compensation of displacement in any direction (axial, transverse, angular) of the straight pipe section.

[0017] Based on the principle of coordinated deformation of the corrugated pipe and the universal structure member, through the ingenious combination design of the corrugated pipe and the structure member, the expansion joint of the present invention can effectively compensate and absorb multi-directional displacements in the axial, transverse, and angular directions of the straight pipe section, and has a small external dimension and stiffness, which can effectively reduce the external installation space. At the same time, the expansion joint of the present invention is provided with a corrugated pipe deformation limiting device, which can control the deformation amount of each corrugated pipe, ensure that each corrugated pipe will not become unstable due to excessive deformation, effectively reduce the pipeline stress, and reduce the pipeline and equipment nozzle stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the compensation scheme of the straight pipe pressure balance type expansion joint in the prior art;

[0019] Figure 2 It is a schematic diagram of the combined compensation scheme of 3 single hinge type expansion joints in the prior art;

[0020] Figure 3 It is a schematic diagram of the compensation scheme of the external pressure straight pipe pressure balance type expansion joint in the prior art;

[0021] Figure 4 It is a schematic diagram of the compensation scheme of the bypass straight pipe pressure balance type expansion joint in the prior art;

[0022] Figure 5 It is a schematic diagram of the compensation scheme of the composite straight pipe balance type expansion joint in the prior art;

[0023] Figure 6 It is a schematic diagram of the structure of the restraint type expansion joint described in the embodiment of the present invention;

[0024] Figure 7 It is a schematic diagram of the pre-displacement of the restraint type expansion joint described in the embodiment of the present invention;

[0025] Figure 8 Schematic diagram of a restraint type expansion joint for a high-pressure straight pipe section according to an embodiment of the present invention;

[0026] Figure 9 Schematic diagram of a restraint type expansion joint for compensating small axial and lateral displacements according to an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 1 - end pipe, 2 - ring plate, 3 - first universal hinge plate, 4 - universal ring, 5 - first pin shaft, 6 - bellows, 7 - second universal hinge plate, 8 - intermediate pipe, 9 - intermediate ring plate, 10 - first limit plate, 11 - first single hinge plate, 12 - second limit plate, 13 - second single hinge plate, 14 - reinforcing ring, 15 - second pin shaft, 16 - third pin shaft Detailed implementation manners

[0029] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the accompanying drawings. It should be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] As Figures 6 to 9As shown in the figure, a constrained expansion joint for straight pipe section compensation includes at least three deformation units. The first deformation unit, the second deformation unit, and the third deformation unit are sequentially connected along the axial direction of the expansion joint. A terminal pipe 1 is connected to the end of the first deformation unit. A ring plate 2 is arranged on the circumferential outer side of the terminal pipe 1. A universal ring 4 is arranged on the circumferential outer side of the bellows 6 of the first deformation unit. The first deformation unit further includes a first universal hinge plate 3. The first universal hinge plate 3 is arranged parallel to the axial direction of the expansion joint. One end of the first universal hinge plate 3 is connected to the ring plate 2, and the other end of the first universal hinge plate 3 is connected to the universal ring 4 through a first pin shaft 5. The first deformation unit and the second deformation unit are connected through an intermediate pipe 8. The first deformation unit and the second deformation unit are mirror-symmetrical. The universal ring 4 of the first deformation unit and the universal ring 4 of the second deformation unit are connected through a second universal hinge plate 7. The second universal hinge plate 7 is arranged parallel to the axial direction of the expansion joint. When the temperature of the pipeline rises and thermal expansion occurs, the constrained expansion joint is subjected to the displacement change thrust caused by thermal expansion from the pipeline or equipment. The bellows of the deformation unit of the constrained expansion joint will generate angular deformation around the pin shaft based on the direction of the displacement. The intermediate pipe of the constrained expansion joint deflects accordingly, making the center line between adjacent two deformation units become a broken line relative to the initial axis. The combination of different directions of the broken line realizes the compensation and absorption of axial, lateral, and angular displacements, effectively meeting the compensation requirements of high-pressure straight pipe sections in narrow spaces with high requirements for the external dimensions of the expansion joint and the force on the pipe support. That is, a metal bellows expansion joint with a smaller external dimension is used to compensate for the multi-directional thermal expansion deformation of the pipeline and equipment, reducing the space occupation and reducing the stress at the pipe orifice of the pipeline and equipment. It can be used for flexible compensation of straight pipe sections in narrow spaces.

[0031] Further, the first universal hinge plate 3 is welded to the ring plate.

[0032] Both ends of the second universal hinge plate 7 are respectively connected to the universal rings 4 of the first deformation unit and the second deformation unit. An intermediate ring plate 9 is arranged on the circumferential outer side of the intermediate pipe 8. The intermediate ring plate 9 is used to fix the second universal hinge plate 7. Preferably, the intermediate ring plate 9 is welded to the second universal hinge plate 7 during use.

[0033] Further, first limit plates 10 are arranged on both the universal ring 4 of the first deformation unit and the universal ring 4 of the second deformation unit. Both ends of the second universal hinge plate 7 are connected to the first limit plates 10 through second pin shafts 15. Thus, the universal ring 4 is fixed on the outer side of the deformation unit through the first universal hinge plate 3 and the second universal hinge plate 7, forming upper and lower fixation and left and right fixation. At the same time, the first limit plates 10 limit the rotation angle of the second universal hinge plate 7, thereby limiting the bending angle of the expansion joint.

[0034] As part of the embodiments of the present invention, the expansion joint of the present invention may include five deformation units. Centered on the midpoint in the axial direction, the two ends of the expansion joint are symmetrical. Both ends of the third deformation unit are connected to the second deformation unit. A first single hinge plate 11 and a second single hinge plate 13 are arranged on the circumferential outer side of the third deformation unit. One end of the first single hinge plate 11 is connected to one end of the second single hinge plate 13 through a third pin 16. The other end of the first single hinge plate 11 is connected to the ring plate 2 of the second deformation unit, and the other end of the second single hinge plate 13 is connected to the ring plate 2 of the second deformation unit at the other end. Further, a second limiting plate 12 is also arranged between the first single hinge plate 11 and the second single hinge plate 13, and the second limiting plate 12 is used to limit the rotation angle of the single hinge plate.

[0035] Further, when the restrained expansion joint only compensates for axial displacement, it is necessary to Figure 7 perform an angular pre-displacement of θ = 0.5 - 1° on the deformation units at both ends of the expansion joint during installation as shown, so as to prompt the expansion joint to quickly respond to the coordinated deformation of the pipeline due to thermal expansion and effectively absorb axial displacement.

[0036] Further, according to the pressure magnitude of the straight pipe section compensated by the restrained expansion joint, when the pressure of the straight pipe section compensated by the restrained expansion joint is relatively large, a reinforced U-shaped bellows can be selected, such as Figure 8 shown, where the reinforced U-shaped bellows is provided with a reinforcing ring 14 at the trough of the bellows.

[0037] Further, two first universal hinge plates 3 are connected by the same first pin 5, and the two first universal hinge plates 3 are respectively located inside and outside the universal ring 4, forming a clamping and fixing effect on the universal ring.

[0038] As part of the embodiments of the present invention, when the axial and lateral displacements to be compensated are relatively small, the expansion joint of the present invention can be designed into a structure including three deformation units, such as Figure 9 shown.

[0039] Through the rotation of the hinge plate around the pin, each bellows generates a moderate angular deformation, and the direct linear connection between the deformation units becomes a broken line connection, shortening the distance between the deformation units, thereby shortening the length of the expansion joint and absorbing the axial displacement of the deformed pipeline; when the pin rotates to drive one end of the expansion joint to rotate downward and the other end to rotate upward, the lateral displacement of the deformed pipeline is absorbed; when the pin rotates to drive the included angle between the two ends of the expansion joint to change, the angular displacement of the deformed pipeline is absorbed. The axial force that pushes the restrained expansion joint to deform is equal to the axial stiffness of one of the bellows multiplied by the axial displacement; the lateral force is equal to the lateral stiffness of two adjacent bellows multiplied by the lateral displacement; the angular deformation force is equal to the angular stiffness of one of the bellows multiplied by the angular displacement.

[0040] The restraint type expansion joint for straight pipe section compensation according to the present invention is based on the principle of coordinated deformation of the bellows and the universal structure member. Through the ingenious combination design of the bellows and the structure member, the expansion joint of the present invention can effectively compensate and absorb the multi-directional displacements in the axial, transverse, and angular directions of the straight pipe section, and has a smaller external dimension and stiffness, which can effectively reduce the external installation space. At the same time, the expansion joint of the present invention is provided with a bellows deformation limiting device, which can control the deformation amount of each bellows, ensure that each bellows will not become unstable due to excessive deformation, effectively reduce the pipeline stress, and reduce the stress of the pipeline and the equipment nozzle.

[0041] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A constrained expansion joint for straight pipe section compensation, characterized in that It includes at least three deformation units. The first deformation unit, the second deformation unit and the third deformation unit are sequentially connected along the axial direction of the expansion joint. A terminal pipe (1) is connected to the end of the first deformation unit. A ring plate (2) is arranged on the circumferential outer side of the terminal pipe (1). A universal ring (4) is arranged on the circumferential outer side of the corrugated pipe (6) of the first deformation unit. The first deformation unit further includes a first universal hinge plate (3). The first universal hinge plate (3) is arranged parallel to the axial direction of the expansion joint. One end of the first universal hinge plate (3) is welded to the ring plate (2). The other end of the first universal hinge plate (3) is connected to the universal ring (4) through a first pin shaft (5). The first deformation unit and the second deformation unit are connected through an intermediate pipe (8). The first deformation unit and the second deformation unit are mirror-symmetrical. The universal rings (4) of the first deformation unit and the second deformation unit are connected through a second universal hinge plate (7). The second universal hinge plate (7) is arranged parallel to the axial direction of the expansion joint. A first single hinge plate (11) and a second single hinge plate (13) are arranged on the circumferential outer side of the third deformation unit. One end of the first single hinge plate (11) is connected to one end of the second single hinge plate (13) through a third pin shaft (16). The other end of the first single hinge plate (11) is connected to the ring plate (2) of the second deformation unit.

2. The constrained expansion joint for straight pipe section compensation according to claim 1, characterized in that, An intermediate ring plate (9) is arranged on the circumferential outer side of the intermediate pipe (8). The intermediate ring plate (9) is used to fix the second universal hinge plate (7).

3. The constrained expansion joint for straight pipe section compensation according to claim 1, wherein First limiting plates (10) are arranged on both the universal rings (4) of the first deformation unit and the second deformation unit. The two ends of the second universal hinge plate (7) are connected to the first limiting plates (10) through second pin shafts (15).

4. The restraint type expansion joint for straight pipe section compensation according to claim 1, characterized in that The expansion joint includes five deformation units. The two ends of the expansion joint are symmetrical with the midpoint in the axial direction as the center. Both ends of the third deformation unit are connected to the second deformation unit.

5. The restraint type expansion joint for straight pipe section compensation according to claim 4, wherein The other end of the second single hinge plate (13) is connected to the ring plate (2) of the second deformation unit at the other end.

6. The restraint type expansion joint for straight pipe section compensation according to claim 1, wherein, A second limiting plate (12) is further arranged between the first single hinge plate (11) and the second single hinge plate (13). The second limiting plate (12) is used to limit the rotation angle of the first single hinge plate (11) and the second single hinge plate (13).

7. The restraint type expansion joint for straight pipe section compensation according to claim 4, characterized in that, When the restraint type expansion joint only compensates for axial displacement, during installation, angular pre-displacements of θ = 0.5~1° are pre-performed on the deformation units at both ends of the expansion joint.

8. The constrained expansion joint for straight pipe section compensation according to claim 1, characterized in that, The corrugated pipe is selected as a reinforced U-shaped corrugated pipe. The reinforced U-shaped corrugated pipe is provided with a reinforcing ring (14) at the wave trough of the corrugated pipe.

9. The restraint type expansion joint for straight pipe section compensation according to claim 1, wherein Two first universal hinge plates (3) are connected by the same first pin shaft (5). The two first universal hinge plates (3) are respectively located on the inner and outer sides of the universal ring (4).

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