Double-layer damping bellows with locking groove

Abstract

The present application relates to the technical field of vibration control and isolation of extra-high voltage reactor oil tank body and manifold system, and particularly relates to a double-layer damping corrugated pipe with locking grooves, which comprises a corrugated pipe body, flanges at both ends of the corrugated pipe body, and a flexible connecting piece connected between the two flanges, the corrugated pipe body comprises a double-layer distributed metal outer pipe and rubber inner pipe, the metal outer pipe is a double omega corrugated pipe with rubber strips at both wave crests and wave troughs, the double omega corrugated pipe comprises a female pipe and a male pipe which are flexibly connected through a locking mechanism, the locking mechanism comprises locking grooves, pre-tightening springs and spherical balls, the locking grooves are distributed axially along the female pipe, and the spherical balls are tightly pressed in the locking grooves by the pre-tightening springs. The present application can meet the requirements of strength and rigidity while having flexibility, significantly improve the compensation deviation performance, and reduce the internal vibration.

Description

Technical Field

[0001] This invention relates to the field of vibration control and vibration isolation technology for the tank body and connecting pipe system of ultra-high voltage reactors, specifically to a vibration-damping bellows with a combination structure of embedded rubber and double Ω-shaped double-layer bellows with locking groove. Background Technology

[0002] Ultra-high voltage (UHV) reactors are key reactive power compensation devices in UHV transmission systems, and their stable operation is crucial for grid security. Corrugated pipes, as key components of oil pipelines, require control over volume changes caused by vibration, temperature variations, and internal pressure fluctuations. During operation, the corrugated pipe is subjected to: 1. Mechanical vibration: from the magnetostriction of the reactor core and the electromagnetic force of the windings; 2. Thermal cycling: oil temperature fluctuations caused by changes in ambient temperature and load; 3. Internal pressure fluctuations: pressure changes caused by changes in oil level and the start / stop of the oil pump.

[0003] These alternating loads can easily cause fatigue cracks in stress concentration areas such as the root of the bellows, ultimately leading to rupture, oil leakage, unplanned equipment shutdowns, and even serious safety accidents. Therefore, optimizing the structural design of bellows has significant practical engineering implications.

[0004] In practical applications, traditional metal bellows have relatively high stiffness, which affects their ability to compensate for displacement in axial, lateral, bending, and torsional directions. In addition, metal bellows and flanges are generally welded structures. At the welding position, annealing caused by high temperature reduces the strength of the heat-affected zone of the weld. The residual thermal stress generated by welding further leads to stress concentration, resulting in a reduced fatigue life and easy cracking. Furthermore, since metal bellows are all-metal structures with low internal resistance, they are prone to local resonance under high-frequency excitation, which cannot be effectively suppressed. Finally, the pipe sections connecting the two ends of the bellows may sometimes experience large axial displacement and torsional motion around the axis under extreme working conditions. Traditional bellows do not compensate enough in these two directions, which can easily cause direct damage to the bellows. Summary of the Invention

[0005] To address the problems of existing metal corrugated pipes, such as high stiffness affecting displacement compensation capabilities, internal vibration during high-frequency vibration, and cracking due to excessively high welding temperatures, this invention provides a rubber-embedded double-Ω-shaped double-layer vibration-damping corrugated pipe that can meet strength and stiffness requirements while also possessing flexibility, significantly improving deviation compensation performance and reducing internal vibration.

[0006] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: A rubber-embedded double-Ω-shaped double-layer vibration-damping bellows with locking grooves comprises two main modules: the bellows body and the connectors. The bellows body includes a double-layered metal outer tube and a rubber inner tube, and the connectors include flexible connectors. By combining flexible and rigid materials, it achieves the characteristics of compensating for deviations, reducing its own internal vibration, and meeting the requirements for strength and stiffness.

[0007] The metal outer tube is a double Ω-shaped bellows, including a male and female tube. The rubber outer tube is a rubber bellows, with rubber strips built into the double Ω-shaped bellows. The double Ω-shaped bellows has a wave-like shell shape, which reduces its own stiffness. The rubber strips embedded at the crests and troughs increase damping. Using a rubber bellows (inner tube) improves resistance to deformation and damage. The overall use of double Ω-shaped double-layer bellows significantly improves resistance to deformation and pressure. It is used to connect two adjacent sections of oil pipe and withstand various forces caused by mechanical vibration, temperature changes, and internal pressure fluctuations.

[0008] The connectors consist of three parts: flange-to-flange connections, flange-to-bellows connections, and male-to-female bellows connections. Four steel wire ropes are used to connect the flanges and secure them with nuts, arranged evenly and symmetrically around the bellows. The flanges are connected to the outer metal pipe using a combination of flared rubber rings and clamps. Rubber strips are embedded in the flange cones, and a rubber ring is placed under each clamp to increase damping. The outer metal pipe is connected to the inner rubber pipe using a combination of movable retaining rings and screws. A movable retaining ring is fitted at the inner rubber pipe interface, and screws are used to connect at the pre-drilled holes at the top and bottom. The rubber interface undergoes a conical deformation due to compression.

[0009] The male and female pipes of the double Ω-type corrugated pipe are flexibly connected by a locking mechanism (a sliding locking spring ball). When the axial force on the corrugated pipe is small, the male and female pipes undergo small deformations, and their locking grooves maintain a statically balanced connection. When the axial force on the corrugated pipe is large, the small deformation of the male and female pipes is insufficient to achieve the required large displacement compensation. At this time, the male and female pipes tend to slide left and right. The ball experiences significant pressure on the side of the female pipe's locking groove, generating a large component force along the axis of the compression spring. When this force increases to a certain extent, the compressed ball retracts, and the ball slides along the locking groove. When the contact force on the ball exceeds a critical value, it momentarily "jumps" from the initial locking groove to an adjacent locking groove. The male and female pipes move alternately on a macroscopic scale, achieving the required displacement compensation and protecting the corrugated pipe from damage. When the corrugated pipe is subjected to torque along the axial direction and undergoes torsional deformation, the ball slides circumferentially along the female pipe's locking groove, thereby compensating for the large axial torsion.

[0010] The flexible connector (steel wire rope) absorbs axial and torsional internal forces and limits lateral displacement, increases tensile stiffness, and the end nut can adjust the axial prestress.

[0011] In order to reduce stress concentration and large deformation at individual defects in the bellows, the rubber strip in this invention can promote the deformation to be more uniform and improve the fatigue life of the bellows.

[0012] To reduce the impact of sudden stiffness changes at metal-to-metal connection points, a rubber strip is embedded inside the flange cone to lower the natural frequency and resonance amplitude, thereby reducing the risk of fatigue fracture.

[0013] To reduce the impact of sudden stiffness changes at metal-to-metal connection points, a rubber ring is placed under the clamp to prevent direct contact between the clamp and corrugated pipes and flanges, thereby reducing the natural frequency and resonance amplitude and improving the safety and stability of the clamp connection.

[0014] The beneficial effects of this invention are: (1) Compensation for deviation: The metal outer tube is a double Ω-shaped corrugated pipe with relatively small longitudinal stiffness and bending stiffness, making it easy to deform. Its enhanced flexibility is beneficial for compensating for deviation. The male and female tubes are connected by a locking groove, which can prevent large deformation damage and is beneficial for compensating for deviation.

[0015] (2) Reduce self-vibration: By adding flexible contacts such as rubber rings at the connection point, the natural frequency and resonance amplitude are reduced, the risk of fatigue fracture is reduced, and better vibration reduction performance is obtained.

[0016] (3) No welding: The flange and the double Ω-type bellows are connected by a combination of tapered pipe connection and clamp connection. The flange and the rubber bellows are connected by a combination of movable circlip and screw. The flange and flange are connected by wire rope connection. There is no welding and it is not easy to crack.

[0017] (4) Prefabricated structure: The prefabricated design is adopted, and the support and connection widely adopt standard parts and conventional processes, which greatly facilitates processing and manufacturing, on-site assembly and later maintenance, and is conducive to technology promotion and practical application. Attached Figure Description

[0018] Figure 1 A schematic diagram of a double-layer vibration-damping corrugated pipe; Figure 2 This is a cross-sectional view of a double-layer vibration-damping corrugated pipe. Figure 3 This is a schematic diagram of a double Ω-shaped bellows. Figure 4 This is a schematic diagram of the steel wire rope structure; Figure 5 This is a schematic diagram of the flange structure; Figure 6 This is a schematic diagram of the clamp structure; Figure 7 This is a schematic diagram of the rubber inner tube. Figure 8 This is a partial enlarged view of the locking mechanism; In the diagram: 1. Metal outer tube, 101. Female tube, 102. Male tube, 103. Small rubber ring, 104. Rubber sealing ring, 105. Flared rubber ring, 106. Large rubber ring, 107. Preload spring, 108. Steel ball, 109. Locking groove, 110. Connecting part, 111. Blind hole; 2. Steel wire cable, 201. Steel wire rope, 202. Double-ended stud, 203. Nut, 204. Nut; 3. Connecting part, 301. Flange lug, 302. Flange body, 303. Flange cone; 4. Clamp, 401. Bolt, 402. Nut, 403. Clamp body; 5. Rubber inner tube, 501. Corrugated pipe body, 502. Set screw, 503. Moving retaining ring. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 This embodiment discloses a double-layer vibration-damping bellows with locking grooves, such as... Figure 1 As shown, it includes a corrugated pipe body, flanges 3 located at both ends of the corrugated pipe body, and a flexible connector connecting the flanges 3 at both ends. In this embodiment, the flexible connector is a steel wire cable 2. The corrugated pipe body includes a double-layered metal outer pipe 1 and a rubber inner pipe 5. The metal outer pipe 1 is a double Ω-shaped corrugated pipe with rubber strips at both the crests and troughs, and the rubber inner pipe 5 is a rubber corrugated pipe.

[0021] like Figure 2 , 3 As shown, the double Ω-shaped corrugated pipe includes a female pipe 101 and a male pipe 102 that are flexibly connected by a locking mechanism. A large rubber ring 106 is provided at the crest of the double Ω-shaped corrugated pipe, and a small rubber ring 103 is provided at the trough. A flared rubber ring 105 is provided on the outer side of the end of the double Ω-shaped corrugated pipe, which compresses the end of the double Ω-shaped corrugated pipe into a tapered shape. A rubber sealing ring 104 is provided on the inner side of the double Ω-shaped corrugated pipe. (Combined with...) Figure 8 The mother tube 101 and the male tube 102 are provided with a connecting part 110. The locking mechanism is provided on the connecting part 110 and includes a locking groove 109, a pre-tightening spring 107 and a ball. Multiple locking grooves 109 are distributed along the axial direction of the mother tube 101. The ball is a steel ball 108 and is pressed against the locking groove 109 by the pre-tightening spring 107.

[0022] In this embodiment, a blind hole 111 is opened on the male tube 102. One end of the preload spring 107 is located in the blind hole 111, and the other end pushes the steel ball 108 into the locking groove 108. In order to achieve compensation during torsional deformation, the locking groove 108 is annular and distributed along the circumference of the female tube 101.

[0023] The locking mechanism enables a flexible connection between the female pipe 101 and the male pipe 102, compensating for bellows deformation caused by external forces. Even with significant external forces, the male and female pipes will not detach, as the number of locking grooves required to prevent detachment can be determined experimentally, and the number of locking grooves can be appropriately set to ensure no detachment. In this embodiment, the female pipe has two or more sets of locking grooves, and the male pipe has two sets of blind holes.

[0024] like Figure 4 As shown, the steel wire cable 2 includes a steel wire rope 201, double-ended studs 202 located at both ends of the steel wire rope 201, and nuts 203 and 204 fastened to the double-ended studs 202.

[0025] like Figure 5 As shown, flange 3 includes flange ears 301, flange body 302, and flange cone 303. The flange ears 301 are evenly distributed along the circumference of flange body 302. Flange cone 303 is located in the center of flange body 302 and has a hole through which the rubber inner tube 5 passes. The steel wire cable is fastened to the flange ears 301 by nuts. Specifically, double-ended studs 202 pass through flange ears 301 and are fastened by nuts 203 and 204.

[0026] like Figure 6 As shown, the clamp includes a clamp body 403, a bolt 401 and a nut 402. The clamp body 403 is annular with protrusions at both ends. The bolt 401 passes through the protrusions and is fastened by the nut 402.

[0027] like Figure 7 As shown, the inner rubber tube 5 is a rubber corrugated tube, including a corrugated tube body 501, a movable retaining ring 503 and a fastening screw 502. The movable retaining ring 503 is sleeved on both ends of the corrugated tube body 501, and the fastening screw 502 passes through the movable retaining ring 503 and the corrugated tube body 501.

[0028] In this embodiment, the double Ω-shaped corrugated pipe (metal outer pipe 1) and the flange 3 are connected by a flared rubber ring 105 and a clamp 4. The flange cone 303 is sleeved on the end of the double Ω-shaped corrugated pipe. The flared rubber ring 105 is on the outside of the double Ω-shaped corrugated pipe, and the clamp is fixed to the outside of the flared rubber ring 105. Specifically, the contracted part of the flared rubber ring 105 faces the inside of the double Ω-shaped corrugated pipe (midpoint direction), and the expanded part faces the outside of the double Ω-shaped corrugated pipe. The flared rubber ring 105 squeezes the end of the double Ω-shaped corrugated pipe into an outwardly expanding conical tube. A rubber sealing ring 104 is provided inside the double Ω-shaped corrugated pipe.

[0029] The outer metal tube 1 and the inner rubber tube 5 are connected together by a flared rubber ring 105, a fastening screw 502 and a movable retaining ring 503. The movable retaining ring 503 is fitted over both ends of the corrugated pipe body 501. The fastening screw 502 passes through the movable retaining ring 503 and the corrugated pipe body 501. The contraction part of the flared rubber ring 105 covers the outside of the fastening screw 502, thus realizing the connection between the outer metal tube 1 and the inner rubber tube 5.

[0030] In this embodiment, the corrugated pipe is designed with inner and outer double layers, and the outer layer is a male and female pipe structure, which reduces the stiffness of the corrugated pipe and enhances the ability to compensate for deviations. Rubber strips are added at the crests and troughs to increase damping and enhance the ability to absorb resonance energy, thereby achieving a vibration reduction effect.

[0031] The bellows mainly consists of two modules: the bellows body and the connectors. Its working principle is based on displacement compensation and flexible connection: it utilizes the elastic deformation of its corrugated thin-walled structure to transmit, compensate, convert, or measure physical quantities such as force, displacement, and pressure, cleverly combining rigid sealing / connection functions with flexible displacement compensation functions.

[0032] The flexible deformation and force / displacement transmission mechanism of bellows: The most basic characteristics of bellows are axial flexibility and axial extensibility. When force or displacement is applied to its ends, it does not resist like a rigid pipe, but absorbs these forces or displacements through elastic deformation (mainly bending deformation) of its corrugated walls.

[0033] Imagine a bellows as a very stiff spring: if you compress it, it shortens, with the troughs and crests of the corrugations moving closer together; if you stretch it, it elongates, with the troughs and crests moving further apart. This unique structure allows it to effectively convert changes in pressure, axial force, or temperature into displacement; conversely, it can also convert axial displacement into changes in force or pressure.

[0034] Operating conditions under different combined loads: 1. Under the "pressure + displacement" condition, the internal pressure generates a force that causes the bellows to elongate, while changes in temperature or air pressure exert an expansion / compression displacement on the pipe. The superposition of these two factors means that the bellows bears both the membrane stress caused by pressure and the bending stress caused by displacement. The total stress is the sum of the two, which is the so-called superposition effect. Fatigue life is calculated based on this combined stress. The double Ω-shaped pipe has relatively low longitudinal and bending stiffness, absorbing more energy from stress or displacement. The male and female bellows move alternately when the stress and displacement are significantly large, thus improving displacement compensation capability. Rubber strips can reduce stress concentration and large deformation at individual defects in the bellows, promoting more uniform deformation distribution and thus improving the fatigue life of the bellows.

[0035] 2. In the case of "pressure + displacement + vibration," such as in the field of vibration control and isolation technology for the UHV reactor tank body and connecting pipe system, the bellows bears system pressure, pipeline thermal displacement, and mechanical vibration generated by the reactor. This vibration superimposes a high-cycle fatigue stress on top of the low-cycle fatigue stress caused by displacement, potentially inducing resonance and leading to rapid fatigue. The inner bellows is made of rubber, providing high damping and effectively resisting deformation and vibration. The rubber strips embedded in the outer bellows further increase damping, reducing resonance amplitude. The steel wire rope, as a flexible connector, also increases overall damping of the bellows, further reducing resonance amplitude and improving torsional displacement compensation, thus lowering the risk of fatigue fracture.

[0036] This invention, through an innovative corrugated pipe structure design, combines the flexibility of rubber and steel wire rope with the low stiffness of a double-Ω-shaped corrugated pipe, successfully constructing a rubber-embedded double-Ω-shaped double-layer vibration-damping corrugated pipe with locking grooves. Those skilled in the art will understand that, without departing from the principles of this invention, the performance of the corrugated pipe can be adjusted by changing the specific dimensions of the corrugated pipe wall and connectors, the prestress of the steel wire rope, the number of locking grooves, etc., and these improvements and modifications should all be included within the scope of protection of this invention.

Claims

1. A double-layer vibration-damping bellows with locking grooves, comprising a bellows body, flanges located at both ends of the bellows body, and a flexible connector connecting the flanges at both ends, characterized in that: The corrugated pipe body includes a double-layered metal outer tube and a rubber inner tube. The metal outer tube is a double Ω-shaped corrugated pipe with rubber strips at both the crests and troughs. The double Ω-shaped corrugated pipe includes a female pipe and a male pipe that are flexibly connected by a locking mechanism. The locking mechanism includes locking grooves, pre-tensioning springs and balls. Multiple locking grooves are distributed along the axial direction of the female pipe, and the balls are pressed against the locking grooves by the pre-tensioning springs.

2. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The male tube has a blind hole. One end of the preload spring is located in the blind hole, and the other end pushes the ball into the locking groove.

3. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The locking groove is annular and distributed along the circumference of the main pipe.

4. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The female and male pipes are provided with connecting parts, and the locking mechanism is provided on the connecting parts.

5. The double-layer vibration-damping bellows with locking groove according to claim 2, characterized in that: The female tube has two or more sets of locking grooves, and the male tube has two sets of blind holes.

6. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The double Ω-shaped bellows and the flange are connected by a flared rubber ring and a clamp. The flange cone is sleeved on the end of the double Ω-shaped bellows, the flared rubber ring is sleeved on the outside of both ends of the double Ω-shaped bellows, and the clamp is fixed on the outside of the flared rubber ring.

7. The double-layer vibration-damping bellows with locking groove according to claim 6, characterized in that: The flared rubber ring squeezes the end of the double Ω-shaped corrugated pipe into an outwardly expanding conical tube, and a sealing rubber ring is provided on the inside of the conical tube.

8. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The outer metal tube and the inner rubber tube are connected together by a flared rubber ring, a fastening screw, and a movable retaining ring. The movable retaining ring is fitted onto the end of the inner rubber tube, and the fastening screw passes through the movable retaining ring and the inner rubber tube. The flared rubber ring is fitted onto the end of the outer metal tube, and its contracted part covers the outside of the fastening screw.

9. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: A flange includes flange ears, a flange body, and a flange cone. The flange ears are evenly distributed along the circumference of the flange body. The flange cone is located in the center of the flange body and has a hole through which the inner rubber tube passes. The flexible connector is fastened to the flange ears by nuts.

10. The double-layer vibration-damping bellows with locking groove according to claim 1, characterized in that: The flexible connector is a steel wire cable, and both ends of the steel wire cable are connected to the flange via nuts.

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