Bellows expansion joint and bellow expansion joint manufacturing method

Abstract

The invention belongs to the technical field of pipelines, and particularly relates to a bellow expansion joint and a bellow expansion joint manufacturing method. The corrugated expansion joint comprises a corrugated pipe, the corrugated pipe comprises a plurality of inner concave parts which are concave towards the central axis direction of the corrugated pipe, the inner concave parts are arranged in the circumferential direction of the corrugated pipe, the inner concave parts are connected side by side in the axial direction of the corrugated pipe, and the outer diameter of the corrugated pipe at the root positions of the inner concave parts is equal to the outer diameters of ports at the two ends of the corrugated pipe. By using the corrugated expansion joint in the technical scheme, when the pipeline expands axially, the corrugated pipe can contract axially, so that the axial expansion of the pipeline is compensated, the internal stress of a pipeline system during working is reduced, the overall quality of the pipeline system is effectively improved, the safety and stability of the pipeline system are protected, and the service life of the pipeline system is prolonged. The service life of the pipeline system is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipelines, and particularly relates to a corrugated expansion joint and a manufacturing method thereof. Background Art

[0002] In a pipeline system for transporting high-temperature and high-pressure media, the pipeline will undergo radial and axial dimensional expansion due to temperature rise. If the axial expansion of the pipeline is not properly compensated, excessive stress will be generated in the pipeline system, which will in turn cause excessive deformation of the pipeline, affecting normal use and even damaging the entire pipeline. By arranging a corrugated expansion joint in the pipeline, the dimensional changes caused by factors such as thermal expansion in the pipeline system can be compensated. The corrugated expansion joint can achieve the telescopic function mainly through the corrugated pipe.

[0003] As Figure 1 shown, the corrugated pipe in the prior art (hereinafter referred to as the outward convex corrugated pipe 10) is outward convex, its inner diameter is close to the inner diameter of the two ends of the pipeline, and the outer diameter is significantly larger than the inner diameter of the pipeline. The outward convex corrugated pipe 10 has a simple structure and is convenient to process, and has been widely used in the field of expansion joints. In previous expansion joint designs, when the pressure of the medium in the pipe can be ignored, engineers have selected the outward convex corrugated pipe 10 as the main compensation element in the expansion joint and adjusted its compensation ability by changing the shape of the corrugations in the outward convex corrugated pipe 10. However, in actual pipeline routes, internal pressure in the pipeline is ubiquitous. When the pipeline is in a state of being filled with internal pressure, the outward convex corrugated pipe 10 itself will undergo lateral and axial expansion, which will lead to two problems: one is to weaken the axial compensation ability during the operation of the expansion joint, which requires a larger-sized expansion joint, increasing the mass of the overall structure; the other is to increase the stress inside the expansion joint, and the increased wall thickness of the outward convex corrugated pipe 10 required for this will also increase the total mass of the structure, and at the same time reduce the service life of the corrugated pipe.

[0004] Currently, inventions regarding corrugated expansion joints focus on aspects such as the sealing performance of the structure, the stress level of the structure, and the stability of the structure. For the problem of poor axial expansion compensation efficiency of pipelines, it is generally only solved by increasing the axial dimension of the expansion joint or increasing the distance between the wave peaks and wave valleys of the corrugated pipe. These methods cannot better meet the usage requirements.

[0005] Therefore, there is an urgent need to propose a corrugated expansion joint and a manufacturing method thereof to solve the problem of pipeline axial expansion. Summary of the Invention

[0006] The purpose of the present invention is to at least solve the problem of how to effectively compensate the axial expansion of the pipeline. This purpose is achieved through the following technical solutions:

[0007] The first aspect of the present invention proposes a corrugated expansion joint, including:

[0008] A bellows, comprising a plurality of inner recesses sunken toward the central axis of the bellows, the inner recesses being arranged circumferentially around the bellows, the plurality of inner recesses being connected side by side along the axial direction of the bellows, the outer diameter of the bellows at the root of the inner recesses being equal to the outer diameter of the ports at both ends of the bellows.

[0009] The present technical solution proposes a concave bellows expansion joint, in which the setting of the concave part makes the bellows have a certain elasticity, so that it can absorb axial, lateral and angular displacements through its own elastic deformation. Therefore, the bellows expansion joint can flexibly respond to external shocks and internal pressures under complex pressure environments. For example, when the bellows expansion joint is working, under the action of the internal pressure of the pipeline, the setting of the concave part makes the bellows produce an axial contraction effect, which can compensate for the axial expansion of the pipeline and reduce the internal stress of the pipeline system when it is working. While the pipeline is radially expanding, the bellows can produce radial expansion at the same time as the pipeline, thereby ensuring the consistency of the structure. In the event of external impact, the concave part on the bellows can alleviate the vibration and pressure waves in the pipeline system and reduce the noise and vibration of the pipeline system. Therefore, the bellows expansion joint provided by the present technical solution can effectively improve the overall quality of the pipeline system, protect the safety and stability of the pipeline system, and extend the service life of the pipeline system.

[0010] In addition, the bellows expansion joint of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, a support structure is provided on the side of the inner recessed portion away from the central axis of the corrugated tube, and the support structure includes a first support portion and a second support portion respectively connected to the two roots of the inner recessed portion, and the first support portion and the second support portion are arranged along the axial direction of the corrugated tube, and there is a gap between the first support portion and the second support portion.

[0012] In some embodiments of the present invention, the cross-sectional shape of the inner recess in the axial direction of the bellows is U-shaped, trapezoidal, S-shaped or Ω-shaped.

[0013] In some embodiments of the present invention, the bellows expansion joint further includes two flanges and two connecting end pipes, each end of the bellows is connected to the flange via the connecting end pipe, and the flange is used to connect to an external component.

[0014] In some embodiments of the present invention, the bellows and the connecting end pipe are threadedly connected.

[0015] In some embodiments of the present invention, a flanging is provided at one end of the connecting end pipe away from the bellows, the flanging is arranged circumferentially around the connecting end pipe, a positioning ring groove is provided on the side of the flange away from the bellows, the flange is sleeved on the connecting end pipe, the flanging is located inside the positioning ring groove, and the flanging and the flange are connected by bolts.

[0016] In some embodiments of the present invention, the bellows expansion joint further includes a plurality of guide shafts arranged axially along the bellows, both ends of the guide shaft pass through the two flanges respectively, and at least one of the flanges can move axially along the guide shaft.

[0017] In some embodiments of the present invention, first nuts and second nuts are provided at both ends of the guide shaft, the first nuts and the second nuts are respectively threadedly connected to the guide shaft, the first nuts are located on the side of the flange away from the bellows, the second nuts are located on the side of the flange facing the bellows, and there is a gap between at least one of the second nuts and the flange. When the bellows contracts, the gap allows the flange to move axially along the guide shaft.

[0018] In some embodiments of the present invention, a lining pipe is arranged inside the bellows, and the first end or the second end of the lining pipe is fixedly connected to the connecting end pipe.

[0019] In a second aspect of the present invention, a method for manufacturing a bellows expansion joint is provided. The method for manufacturing a bellows expansion joint is used to manufacture the above-mentioned bellows expansion joint, and the method for manufacturing a bellows expansion joint includes:

[0020] Printing the bellows by using a metal additive manufacturing method, and the additive manufacturing direction is the axial direction of the bellows;

[0021] On the side away from the central axis of the bellows, a support ring is printed between two adjacent inner concave portions, and the two adjacent inner concave portions are connected by the support ring;

[0022] After printing is completed, the middle part of the support ring is removed to form a first support portion and a second support portion arranged at intervals. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0024] Figure 1 Schematically shows a cross-sectional view of an outwardly convex bellows in the prior art;

[0025] Figure 2 Schematically shows a cross-sectional view of a corrugated pipe (the cross-sectional shape of the concave portion in the axial direction of the corrugated pipe is U-shaped) according to an embodiment of the present invention;

[0026] Figure 3 Schematically shows a cross-sectional view of a corrugated pipe (the cross-sectional shape of the concave portion in the axial direction of the corrugated pipe is trapezoidal) according to an embodiment of the present invention;

[0027] Figure 4 Schematically shows a cross-sectional view of a corrugated pipe (the cross-sectional shape of the concave portion in the axial direction of the corrugated pipe is S-shaped) according to an embodiment of the present invention;

[0028] Figure 5 Schematically shows a cross-sectional view of a corrugated pipe (the cross-sectional shape of the concave portion in the axial direction of the corrugated pipe is Ω-shaped) according to an embodiment of the present invention;

[0029] Figure 6 Schematically shows a cross-sectional view of a partial structure of a corrugated pipe according to an embodiment of the present invention;

[0030] Figure 7 Schematically shows a cross-sectional view of a partial structure of a metal additive manufacturing component according to an embodiment of the present invention;

[0031] Figure 8 Schematically shows a structural view of a corrugated expansion pipe according to an embodiment of the present invention;

[0032] Figure 9 Schematically shows a structural view of a lining pipe according to an embodiment of the present invention;

[0033] Figure 10 Partial structural view of the outwardly convex corrugated pipe used for calculation;

[0034] Figure 11 Partial structural view of the inwardly concave corrugated pipe used for calculation;

[0035] Figure 12 Schematically shows a graph of the relationship between the axial length of the outwardly convex corrugated pipe and the inwardly concave corrugated pipe and the internal pressure of the pipeline.

[0036] The reference numerals in the drawings are represented as follows:

[0037] 10. Outwardly convex corrugated pipe; 11. Outwardly convex portion; 11a. Top of the outwardly convex portion; 11b. Root of the outwardly convex portion;

[0038] 100, Bellows; 110, Concave portion; 111, Top; 112, Root; 120, Support ring; 130, Support structure; 131, First support portion; 132, Second support portion; 140, Spacing;

[0039] 200, Flange; 210, Annular structure; 220, Connection portion; 300, Connecting end pipe; 400, Guide shaft; 500, Liner tube; 510, Straight pipe section; 520, Reducing pipe section. Detailed implementation manners

[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0041] It should be understood that the terms used herein are for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless otherwise clearly specified in the context, the singular forms "a", "an" and "the" as used herein may also include the plural forms. The terms "include", "comprise", "contain" and "have" are inclusive and thus specify the presence of the stated features, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the execution order is explicitly stated. It should also be understood that additional or alternative steps may be used.

[0042] Although the terms first, second, third, etc. may be used herein to describe multiple elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless explicitly stated in the context, terms such as "first", "second", and other numerical terms do not imply an order or sequence when used herein. Therefore, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0043] For ease of description, spatially relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure with respect to another element or feature. Such relative relationship terms include, for example, "inner", "outer", "inner side", "outer side", "below", "beneath", "above", "over" and the like. Such spatially relative relationship terms are intended to include different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figure is flipped, an element described as "below" or "beneath" another element or feature will then be oriented "above" or "over" the other element or feature. Thus, the exemplary term "below" can include both an orientation above and below.

[0044] Figure 1 A schematic cross-sectional view of a bellows 10 in the prior art is shown. As Figure 1 shown, the externally convex bellows 10 in the prior art includes a plurality of externally convex portions 11 protruding in a direction away from the central axis of the bellows 10. The externally convex portions 11 are arranged circumferentially around the externally convex bellows 10, and the plurality of externally convex portions 11 are arranged side by side along the axial direction of the externally convex bellows 10. The outer diameter of the externally convex bellows 10 at the top 11a position of the externally convex portion 11 is larger than the outer diameter of both ends, and the inner diameter of the externally convex bellows 10 at the root 11b position of the externally convex portion 11 is equal to the inner diameter of both ends of the externally convex bellows 10. When the corrugated expansion joint uses the externally convex bellows 10, it can only be applied to the case where there is no internal pressure in the pipeline. When the pipeline conveys high-temperature and high-pressure media, the externally convex bellows 10 cannot provide a good compensation effect for the axial expansion of the pipeline, and the protection effect on the pipeline system is poor. The corrugated expansion joint provided by the present technical solution can effectively solve the problems existing in the prior art.

[0045] Figure 2 A schematic structural view of a corrugated expansion tube according to an embodiment of the present invention is shown. As Figure 2 shown, the present invention provides a corrugated expansion joint, which includes a bellows 100. The bellows 100 includes a plurality of concave portions 110 recessed in a direction towards the central axis of the bellows 100. The concave portions 110 are arranged circumferentially around the bellows 100, and the plurality of concave portions 110 are connected side by side along the axial direction of the bellows 100. The outer diameter of the bellows 100 at the root 112 position of the concave portion 110 is equal to the outer diameter of both ends of the bellows 100.

[0046] This technical solution proposes an in - concave corrugated expansion joint. The setting of the in - concave part 110 endows the corrugated pipe 100 with certain elasticity, so that it can absorb axial, lateral and angular displacements through its own elastic deformation. Therefore, this corrugated expansion joint can flexibly cope with external impacts and internal pressures in a complex pressure environment. For example, when the corrugated expansion joint is working, under the action of the internal pressure of the pipeline, the setting of the in - concave part 110 causes the corrugated pipe 100 to produce an axial contraction effect, which can compensate for the axial expansion of the pipeline and reduce the internal stress during the operation of the pipeline system. When the pipeline expands radially, the corrugated pipe 100 can expand radially simultaneously with the pipeline, thus ensuring the structural consistency. In the case of external impact, the in - concave part 110 on the corrugated pipe 100 can relieve the vibration and pressure waves in the pipeline system, reducing the noise and vibration of the pipeline system. Therefore, the corrugated expansion joint provided by this technical solution can effectively improve the overall quality of the pipeline system, maintain the safety and stability of the pipeline system, and extend the service life of the pipeline system.

[0047] It can be understood that since the in - concave part 110 is recessed towards the inside of the corrugated pipe 100, the inner diameter of the corrugated pipe 100 at the top 111 position of the in - concave part 110 is significantly smaller than the inner diameters of the two ends of the corrugated pipe 100. The size of the in - concave part 110 in the radial direction of the corrugated pipe 100, the size of the in - concave part 110 in the axial direction of the corrugated pipe 100, and the number of the in - concave parts 110 can be set according to the structure of the pipeline and the internal pressure of the pipeline during the actual working process, ensuring that the corrugated pipe 100 can effectively compensate for the axial expansion of the pipeline, ensuring that it will not deform and fail under extreme conditions, and at the same time having good fatigue resistance. In the pipeline system where the corrugated pipe 100 is located, the outer diameter of the corrugated pipe 100 is similar to the outer diameters of the two - end pipelines, while the inner diameter of the corrugated pipe 100 is significantly smaller than the inner diameter of the pipeline. Optionally, the material of the corrugated pipe 100 can be a metal material such as stainless steel or alloy.

[0048] Furthermore, referring to Figures 2 to 5 , the cross - sectional shape of the in - concave part 110 in the axial direction of the corrugated pipe 100 can be U - shaped, trapezoidal, S - shaped or Ω - shaped. Figure 2 As shown, the cross - sectional shape of the in - concave part 110 of the corrugated pipe 100 is U - shaped, with its top 111 and root 112 being arc - shaped and the part between the top 111 and the root 112 being linear. Figure 3 As shown, the cross - sectional shape of the in - concave part 110 of the corrugated pipe 100 is trapezoidal, with its top 111 and root 112 both being linear and the part between the top 111 and the root 112 being linear. Figure 4 As shown, the cross - sectional shape of the in - concave part 110 of the corrugated pipe 100 is S - shaped, with its top 111 and root 112 being arc - shaped and the part between the top 111 and the root 112 being transitioned through an S - shaped curve. Figure 5The cross-sectional shape of the concave portion 110 of the bellows 100 shown is Ω-shaped, its top 111 is arc-shaped, its root 112 is linear, and the top 111 and the root 112 are transitioned by an arc. Of course, the shape of the concave portion 110 is not limited to this and can be set according to specific usage requirements.

[0049] Furthermore, Figure 6 Schematically shown is a schematic cross-sectional view of a partial structure of the bellows 100 according to an embodiment of the present invention. Refer to Figure 6 , on the side of the concave portion 110 facing away from the central axis of the bellows 100, a support structure 130 is provided. The support structure 130 includes a first support portion 131 and a second support portion 132 respectively connected to the two roots 112 of the concave portion 110. The first support portion 131 and the second support portion 132 are arranged along the axial direction of the bellows 100, and there is a gap 140 between the first support portion 131 and the second support portion 132.

[0050] It can be understood that during the axial contraction of the bellows 100, the concave portion 110 is squeezed, and its two roots 112 approach each other, so that the first support portion 131 and the second support portion 132 will approach each other, and the gap between them gradually decreases. In the case of a relatively large amount of shrinkage deformation, the first support portion 131 and the second support portion 132 will abut against each other. Therefore, by providing the first support portion 131 and the second support portion 132 at the roots 112 of the concave portion 110, a support and limiting effect can be exerted on the concave portion 110, avoiding the problem of being crushed due to excessive shrinkage deformation of the bellows 100 and further causing structural failure.

[0051] In this embodiment, both the first support portion 131 and the second support portion 132 are annular structures 210, and the lengths of the first support portion 131 and the second support portion 132 in the axial direction of the bellows 100 are the same, so as to avoid different deformation amounts of different concave portions 110 during contraction, thereby avoiding uneven force among the concave portions 110. In other embodiments, the first support portion 131 and the second support portion 132 may also be a plurality of protrusions or arc-shaped ribs arranged at intervals 140 along the outer circumference of the roots 112 of the concave portion 110, as long as they can play a role in support and limitation during the large deformation process of the bellows 100.

[0052] Optionally, the corrugated pipe 100 provided by this technical solution is made by metal additive manufacturing technology. Metal additive manufacturing technology uses metal powder or wire as raw materials and melts and deposits the materials layer by layer through high-energy beams (such as lasers, electron beams, etc.) to manufacture high-performance metal components. This technology is based on a computer three-dimensional CAD (Computer Aided Design) data model. Using the principle of discrete-packing, through the control of software and numerical control systems, the materials are melted and deposited layer by layer to finally form the required metal parts. Different from traditional manufacturing methods, metal additive manufacturing technology is almost not limited by shape and can print metal components with complex structures and geometries, which is very suitable for the production of the corrugated pipe 100. Using metal additive manufacturing technology can directly convert metal powder or wire into the structure of the corrugated pipe 100, thus greatly reducing the generation of waste. Moreover, metal additive manufacturing technology can achieve extremely high printing accuracy and can print the corrugated pipe 100 with precise dimensions.

[0053] Furthermore, Figure 7 Schematically shows a partial structural cross-sectional view of a metal additive manufacturing formed component according to an embodiment of the present invention. Refer to Figure 7 , in this technical solution, the additive manufacturing direction is the axial direction of the corrugated pipe 100 (the X-axis direction in the figure). During the printing process, a support ring 120 is formed between the roots 112 of the concave portion 110, and the support ring 120 connects the two roots 112 of the concave portion 110. The support ring 120 can support the concave portion 110 during the printing process to prevent the concave portion 110 from collapsing, bending or other uncontrollable deformations. After printing, the middle part of the support ring 120 is removed by machining, so that the support ring 120 is divided into a first support portion 131 and a second support portion 132. Machining can use numerical control machining technology and cut the support ring 120 through numerical control equipment such as a laser cutting machine. Of course, in some embodiments, the support ring 120 can also be completely removed by machining means.

[0054] Furthermore, Figure 8 Schematically shows a structural view of a corrugated expansion pipe according to an embodiment of the present invention. Refer to Figure 8 , the corrugated expansion joint further includes two flanges 200 and two connecting end pipes 300. Each end of the corrugated pipe 100 is connected through the connecting end pipe 300 and the flange 200, and the flange 200 is used to connect to external components (such as pipes).

[0055] Understandably, the provision of the connecting end pipe 300 enables the connection of the corrugated pipe 100 and the flange 200, and the flange 200 enables the connection of the corrugated expansion joint and the pipeline. Optionally, the connection between the corrugated pipe 100 and the connecting end pipe 300 is detachable, and the connection between the connecting end pipe 300 and the flange 200 is also detachable, thus facilitating the maintenance and servicing of the corrugated expansion joint. When the components in the corrugated expansion joint become aged or damaged, they can be removed for replacement. Additionally, the connection between the corrugated pipe 100 and the connecting end pipe 300, as well as the connection between the connecting end pipe 300 and the flange 200, should be a sealed connection to prevent the leakage of the medium in the pipeline system. To enhance the structural sealing performance, sealing structures such as sealing rings or gaskets can be provided.

[0056] Furthermore, the corrugated pipe 100 and the connecting end pipe 300 are connected by threads.

[0057] The corrugated pipe 100 and the connecting end pipe 300 are connected by threads, which is convenient for loading and unloading, provides stable connection, and can ensure good sealing performance between the two. Exemplarily, external threads are provided at both ports of the corrugated pipe 100, and internal threads are provided at the end of the connecting end pipe 300 for connecting with the corrugated pipe 100. The corrugated pipe 100 and the connecting end pipe 300 are threadedly connected through the external threads and the internal threads.

[0058] Furthermore, a flanging (not shown in the figure) is provided at the end of the connecting end pipe 300 away from the corrugated pipe 100. The flanging is provided circumferentially along the connecting end pipe 300. A positioning ring groove is provided on the side of the flange 200 facing away from the corrugated pipe 100. The flange 200 is sleeved on the connecting end pipe 300, and the flanging is located inside the positioning ring groove. The flanging and the flange 200 are connected by bolts.

[0059] The connection through the flanging and the flange 200 can enhance the sealing performance between the flange 200 and the connecting end pipe 300 and prevent the leakage of the internal medium. Threaded holes are provided on both the flange 200 and the flanging, and the threaded holes on the flange 200 and the threaded holes on the flanging are correspondingly arranged, so that they can be locked by bolts. Optionally, a sealing ring is provided between the flanging and the flange 200 to enhance the sealing performance between the flanging and the flange 200 by providing the sealing ring. Optionally, a sealing ring positioning groove is provided on the side of the flanging facing the flange 200 or at the bottom of the positioning ring groove. The sealing ring is partially located in the sealing ring positioning groove, thereby limiting the position of the sealing ring and preventing the sealing ring from shifting during the assembly process or the working process.

[0060] Furthermore, continuing to refer to Figure 8 , the corrugated expansion joint further includes a plurality of guide shafts 400 arranged axially along the corrugated pipe 100. Both ends of the guide shafts 400 pass through the two flanges 200 respectively, and at least one flange 200 can move axially along the guide shafts 400.

[0061] The guide shaft 400 is used to constrain the lateral movement of the bellows 100 and guide the movement of the flange 200 to prevent the bellows expansion joint from becoming unstable during operation. It can be understood that at least one flange 200 can move along the axial direction of the guide shaft 400, that is, when the bellows 100 contracts axially, the flange 200 on at least one side can move with the bellows 100, thereby meeting the need for the bellows expansion tube to shrink and deform as a whole.

[0062] Optionally, the flange 200 includes an annular structure 210 and a plurality of connecting parts 220, wherein the annular structure 210 is used to connect to the connecting end pipe 300, the plurality of connecting parts 220 are connected to the outside of the annular structure 210, the plurality of connecting parts 220 are arranged at intervals of 140 along the outer periphery of the annular structure 210, and the guide shaft 400 is passed through the connecting parts 220. The connecting parts 220 on the two flanges 200 are arranged one by one, so as to ensure that the guide shaft 400 is parallel to the central axis of the corrugated tube 100. In this embodiment, each flange 200 is provided with four connecting parts 220, and the two flanges 200 are connected by four guide shafts 400. In other embodiments, the number of connecting parts 220 and guide shafts 400 is set according to the use requirements, and is not specifically limited here.

[0063] Further, both ends of the guide shaft 400 are provided with a first nut and a second nut, which are respectively threadedly connected to the guide shaft 400, the first nut is located on the side of the flange 200 away from the bellows 100, and the second nut is located on the side of the flange 200 facing the bellows 100, and there is a gap between at least one second nut and the flange 200, and when the bellows 100 contracts, the gap allows the flange 200 to move along the axial direction of the guide shaft 400. It can be understood that the size of the gap limits the moving distance of the flange 200, and therefore, the size of the gap can be set according to the actual required contraction amount of the bellows 100, and preferably, the size of the gap is greater than or equal to the maximum contraction amount of the bellows 100.

[0064] Optionally, the guide shaft 400 may be a threaded rod, or an external thread may be provided only at the portion where the guide shaft 400 and the nut are connected. It is understandable that the flange 200 may be locked on the guide shaft 400 by the first nut and the second nut. By reserving a certain gap between the second nut and the flange 200, the flange 200 may be allowed to move along the guide shaft 400. The first nut and the second nut are arranged so that the assembly is convenient and the disassembly is easy, and the position of the nut can be flexibly adjusted according to the actual use requirements, so that it plays a role of locking or limiting.

[0065] Further, Figure 9 The structure diagram of the liner pipe 500 according to the embodiment of the present invention is schematically shown. Figure 8 andFigure 9 Inside the corrugated pipe 100, a lining pipe 500 is arranged, and the first end or the second end of the lining pipe 500 is fixedly connected to the connecting end pipe 300.

[0066] The lining pipe 500 is mainly used to prevent the medium from directly contacting the corrugated pipe 100, so as to reduce the corrosion effect of the medium on the corrugated pipe 100. Therefore, the lining pipe 500 is preferably made of high-temperature resistant and corrosion-resistant materials such as stainless steel, so that the high-temperature resistant and corrosion-resistant performance of the pipeline system can be greatly improved. Optionally, the material of the lining pipe 500 can be non-metallic materials such as polyethylene and polypropylene with good corrosion resistance and friction performance.

[0067] It can be understood that the lining pipe 500 is only connected to the connecting end pipe 300 at one end, so that the connecting end pipe 300 not connected to the lining pipe 500 can move relative to the lining pipe 500 to meet the contraction requirement of the corrugated expansion joint. Optionally, which specific connecting end pipe 300 is connected to the lining pipe 500 can be determined according to the flow direction of the medium. Preferably, connecting the medium inlet end of the lining pipe 500 to the connecting end pipe 300 can play a good guiding role for the medium, reduce the residue of the medium between the corrugated pipe 100 and the lining pipe 500, and thus extend the service life of the corrugated expansion joint and even the entire pipeline system.

[0068] Furthermore, according to the structure of the corrugated pipe 100 in the present technical solution, the inner diameter at the position of the top 111 of the concave part 110 is smaller than the inner diameters of the two ends of the corrugated pipe 100. Therefore, the outer diameter of the middle part of the lining pipe 500 is smaller than the outer diameters of the two ends of the lining pipe 500, so as to avoid interference between the lining pipe 500 and the top 111 of the concave part 110. Exemplarily, the lining pipe 500 includes a straight pipe section 510 and reduced-diameter pipe sections 520 respectively connected to both ends of the straight pipe section 510, and one of the reduced-diameter pipe sections 520 is used to connect to the connecting end pipe 300. The inner diameter of the end of the reduced-diameter pipe section 520 connected to the straight pipe section 510 is smaller than the inner diameter of the end of the reduced-diameter pipe section 520 far from the straight pipe section 510. Optionally, the reduced-diameter pipe section 520 is an arc surface in the axial direction, so that the flow of the medium can be smoother, effectively reducing fouling and blockage, and extending the service life of the pipeline system.

[0069] Furthermore, the axial lengths of the externally convex corrugated pipe 10 in the prior art and the internally concave corrugated pipe 100 in the present technical solution under a certain pipeline internal pressure are calculated by means of numerical simulation. The externally convex corrugated pipe 10 and the internally concave corrugated pipe 100 used in the calculation are applicable to the same pipeline system. Figure 10 It is a partial structural schematic diagram of the externally convex corrugated pipe 10 used in the calculation, Figure 11 It is a partial structural schematic diagram of the internally concave corrugated pipe 100 used in the calculation, and its main structural parameters are as follows:

[0070]

[0071]

[0072] Figure 12 The relationship diagram between the axial length of the convex bellows 10 and the concave bellows 100 and the internal pressure of the pipeline is schematically shown. Among them, ① represents the relationship between the axial length of the convex bellows 10 and the internal pressure of the pipeline, and the relationship is: L = 23P + L0; ② represents the relationship between the axial length of the concave bellows 100 and the internal pressure of the pipeline, and the relationship is: L = -25P + L0. It can be seen that as the internal pressure of the pipeline increases, the axial length of the concave bellows 100 provided by the present technical solution gradually decreases, while the axial length of the convex bellows 10 in the prior art gradually increases, that is, the concave bellows 100 can play a good role in compensating for the axial expansion of the pipeline.

[0073] At present, there are five main forming methods for metal bellows: hydraulic forming, rolling forming, spinning forming, expansion forming, and welding forming. The first four are cold forming, and welding forming is hot forming. However, these traditional methods are not suitable for processing the concave bellows 100 proposed in this technical solution, especially the special-shaped concave bellows 100. Therefore, this technical solution also provides a bellows expansion joint manufacturing method to solve the above problems.

[0074] The bellows expansion joint manufacturing method is used to manufacture the bellows expansion joint in the above embodiment, and the bellows expansion joint manufacturing method comprises:

[0075] The bellows 100 is printed by a metal additive manufacturing method, the additive manufacturing direction is the axial direction of the bellows 100, and a support ring 120 is printed between two adjacent inner recesses 110 on the side away from the central axis of the bellows 100, and the two adjacent inner recesses 110 are connected by the support ring 120;

[0076] After printing is completed, the middle portion of the support ring 120 is removed to form a first support portion 131 and a second support portion 132 disposed at an interval 140 .

[0077] Optionally, the corrugated pipe 100 is prepared by using the laser powder bed fusion technology in the metal additive manufacturing method. The core of the laser powder bed fusion technology is laser melting. During the manufacturing process, first, the metal powder is evenly spread on the manufacturing platform, and then, a laser beam is used to scan the metal powder, locally heating and melting it. The power and scanning speed of the laser beam can be controlled to achieve precise control of the melting process. Once the melting is completed, the molten metal will quickly solidify to form a solid layer, and then the metal powder is laid on it, repeating the above steps until the entire part is printed. The laser powder bed fusion technology has unique advantages such as high flexibility, fast processing speed, and no restrictions on the size and shape of the sample, and is very suitable for the production and manufacturing of the corrugated pipe 100.

[0078] During the printing process, the support ring 120 can play a role in supporting the root 112 of the concave portion 110, thereby preventing the concave portion 110 from collapsing, bending or other uncontrollable deformations due to being suspended, ensuring the stability of the overall structure of the corrugated pipe 100, and effectively improving the yield.

[0079] Since the corrugated pipe 100 needs to have a certain ability of axial shrinkage deformation, after printing, a part of the support ring 120 can be removed to create a gap for shrinkage. The first support portion 131 and the second support portion 132, as the axial limiting structures of the corrugated pipe 100, can approach and even abut against each other during the shrinkage process of the corrugated expansion joint, thereby preventing the corrugated pipe 100 from failing due to excessive deformation. Preferably, the middle position of the support ring 120 is removed to ensure the symmetry of the first support portion 131 and the second support portion 132, thereby ensuring the balanced force of the overall structure during the shrinkage process. Of course, in some embodiments, the support ring 120 can also be completely removed. Optionally, the removal of the support ring 120 is carried out by machining. For example, a numerical control device such as a laser cutting machine can be used to make the processing process efficient and convenient.

[0080] After cutting is completed, the corrugated pipe 100 is assembled with the connecting end pipe 300, the inner lining pipe 500, the flange 200, and the guide shaft 400 to form a complete corrugated expansion joint structure.

[0081] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A corrugated expansion joint, characterized in that, The corrugated expansion joint includes: A corrugated pipe (100), the corrugated pipe (100) includes a plurality of concave portions (110) recessed toward the central axis direction of the corrugated pipe (100), the concave portions (110) are arranged around the circumferential direction of the corrugated pipe (100), and the plurality of concave portions (110) are connected side by side along the axial direction of the corrugated pipe (100). The outer diameter of the corrugated pipe (100) at the root (112) position of the concave portion (110) is equal to the outer diameter of both ends of the corrugated pipe (100).

2. The corrugated expansion joint according to claim 1, wherein On the side of the concave portion (110) facing away from the central axis of the corrugated pipe (100), a support structure (130) is provided. The support structure (130) includes a first support portion (131) and a second support portion (132) respectively connected to the two roots (112) of the concave portion (110). The first support portion (131) and the second support portion (132) are arranged along the axial direction of the corrugated pipe (100), and there is a gap (140) between the first support portion (131) and the second support portion (132).

3. The corrugated expansion joint according to claim 1, wherein The cross-sectional shape of the concave portion (110) in the axial direction of the corrugated pipe (100) is U-shaped, trapezoidal, S-shaped or Ω-shaped.

4. The corrugated expansion joint according to claim 1, characterized in that, The corrugated expansion joint further includes two flanges (200) and two connecting end pipes (300). Each end of the corrugated pipe (100) is connected through the connecting end pipe (300) and the flange (200), and the flange (200) is used to connect with external components.

5. The corrugated expansion joint according to claim 4, characterized in that, The corrugated pipe (100) and the connecting end pipe (300) are threadedly connected.

6. The corrugated expansion joint according to claim 4, characterized in that, One end of the connecting end pipe (300) away from the corrugated pipe (100) is provided with a flanging. The flanging is arranged around the circumferential direction of the connecting end pipe (300). On the side of the flange (200) facing away from the corrugated pipe (100), a positioning ring groove is provided. The flange (200) is sleeved on the connecting end pipe (300), the flanging is located inside the positioning ring groove, and the flanging and the flange (200) are connected by bolts.

7. The corrugated expansion joint according to claim 6, characterized in that, The corrugated expansion joint further includes a plurality of guide shafts (400) arranged along the axial direction of the corrugated pipe (100). Both ends of the guide shaft (400) pass through the two flanges (200) respectively, and at least one flange (200) can move along the axial direction of the guide shaft (400).

8. The corrugated expansion joint according to claim 7, wherein, Both ends of the guide shaft (400) are provided with a first nut and a second nut. The first nut and the second nut are respectively threadedly connected to the guide shaft (400). The first nut is located on the side of the flange (200) facing away from the corrugated pipe (100), and the second nut is located on the side of the flange (200) facing the corrugated pipe (100). There is a gap between at least one second nut and the flange (200). When the corrugated pipe (100) contracts, the gap allows the flange (200) to move along the axial direction of the guide shaft (400).

9. The bellows expansion joint according to any one of claims 4-8, characterized in that, An inner lining tube (500) is inserted into the interior of the corrugated tube (100), and the first end or the second end of the inner lining tube (500) is fixedly connected to the connecting end tube (300).

10. A manufacturing method of a corrugated expansion joint, characterized in that, Used to manufacture a corrugated expansion joint according to any one of claims 1 to 9, the corrugated expansion joint manufacturing method comprising: The bellows (100) is printed using a metal additive manufacturing method, the additive manufacturing direction is the axial direction of the bellows (100), a support ring (120) is printed between two adjacent inner recesses (110) on a side away from the central axis of the bellows (100), and the two adjacent inner recesses (110) are connected via the support ring (120); After printing is completed, the middle portion of the support ring (120) is removed, so that the support ring (120) forms a first support portion (131) and a second support portion (132) arranged at a distance (140).

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