Cam balanced bellows compensator
The cam-balanced bellows compensator solves the problems of excessive bellows and thrust output in existing technologies by welding a mandrel and a groove plate onto the outer circle of the ring plate and using the reaction force of the cam groove to counteract the thrust of the fluid medium, thereby reducing the size and cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU WUXING BELLOWS CO LTD
- Filing Date
- 2023-10-04
- Publication Date
- 2026-07-31
AI Technical Summary
Existing balanced bellows compensators require the use of three bellows, which increases their length and outer diameter, and the output thrust can damage external equipment.
A cam-balanced bellows compensator is adopted. Multiple mandrels are welded on the outer circle of the second ring plate. The mandrels are fitted with grooved plates with cam grooves. A column is inserted and connected to a crossbar. The cam groove generates a reaction force on the movement of the column to counteract the axial thrust of the fluid medium.
The number of bellows used is reduced, the size and production cost of the compensator are lowered, and the thrust of the fluid medium is effectively offset, reducing damage to external equipment.
Smart Images
Figure CN117366371B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a bellows compensator used to compensate for the thermal expansion and contraction of pipelines. Background Technology
[0002] A bellows compensator comprises a bellows with connecting pipes at both ends. These connecting pipes are connected in series in a pipeline. The fluid medium in the bellows exerts a thrust on the bellows, which is transmitted through the pipeline to connected external equipment, potentially causing damage. To prevent this thrust from being output outward, existing technology often employs a balanced bellows compensator, which has three bellows: a first working bellows, a second working bellows, and a balanced bellows. The right end of the first working bellows is connected to the left end of the balanced bellows, and the right end of the balanced bellows is connected to the left end of the second working bellows. A tie rod connects the left ends of the first and second working bellows, and another tie rod connects the right ends of the first and second working bellows. The average cross-sectional area of the balanced bellows is twice that of the first working bellows, and the first and second working bellows have identical structures. Balanced bellows compensators require the use of three bellows, which greatly increases their length and outer diameter. Summary of the Invention
[0003] The purpose of this invention is to reduce the number of bellows used and the volume of the bellows compensator while reducing the outward output thrust of the compensator.
[0004] The technical solution of the present invention is a cam-balanced bellows compensator, which includes a first bellows 4, a second bellows 13, a second ring plate 11 welded between the first bellows 4 and the second bellows 13, a first ring plate 2 welded to the left end of the first bellows 4, and a third ring plate 15 welded to the right end of the second bellows 13. The feature is that multiple mandrels 9 are symmetrically welded on the outer circle of the second ring plate 11, each mandrel having a flange 10 at its root. A groove plate 7 is fitted onto the mandrel, and a first cam groove 17 and a second cam groove 18 are symmetrically provided on the groove plate. A first column 6 is inserted into the first cam groove and is fixedly connected to the first ring plate 2 via a first crossbar 5. A second column 12 is inserted into the second cam groove and is fixedly connected to the third ring plate 15 via a second crossbar 14.
[0005] The present invention is characterized in that the cam groove has a reaction force on the movement of the column, which can counteract the axial thrust generated by the fluid medium in the bellows, thereby greatly reducing the thrust output by the compensator.
[0006] Its advantages include eliminating the balance bellows, which helps reduce production costs, and reducing the size of the compensator, making it easier to transport and install. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of the structure of the present invention.
[0008] Figure 2 This is a schematic diagram of the forces acting on the first cam groove.
[0009] Reference numerals in the attached diagram: 1-First connecting pipe, 2-First ring plate, 3-Adjusting nut, 4-First bellows, 5-First crossbar, 6-First column, 7-Slot plate, 8-Butterfly spring, 9-Mandrel, 10-Flange, 11-Second ring plate, 12-Second column, 13-Second bellows, 14-Second crossbar, 15-Third ring plate, 16-Second connecting pipe, 17-First cam groove, 18-Second cam groove. Implementation
[0010] A cam-balanced bellows compensator includes a first bellows 4 and a second bellows 13. The right end of the first bellows 4 is welded to the left end of a second ring plate 11, and the left end of the second bellows 13 is welded to the right end of the second ring plate 11. A first connecting pipe 1 is welded to the left end of the first bellows 4, and a first ring plate 2 is welded to the first connecting pipe 1. A second connecting pipe 16 is welded to the right end of the second bellows 13, and a third ring plate 15 is welded to the second connecting pipe.
[0011] Multiple mandrels 9 are symmetrically arranged on the outer circle of the second ring plate 11. The flanges 10 at the root of the mandrels are welded to the outer circle of the second ring plate. A groove plate 7 is fitted on the mandrel. A first cam groove 17 and a second cam groove 18 are symmetrically arranged on the groove plate. The first cam groove and the second cam groove do not penetrate the groove plate, but are recessed into the groove plate. A first column 6 is inserted into the first cam groove. The first column is fixedly connected to the right end of the first crossbar 5. The left end of the first crossbar is fixedly connected to the first ring plate 2 by a nut 3. A second column 12 is inserted into the second cam groove. The second column is fixedly connected to the left end of the second crossbar 14. The right end of the second crossbar 14 is fixedly connected to the third ring plate 15 by a nut.
[0012] This compensator can eliminate the axial thrust of the fluid medium in the bellows, such as Figure 2 As shown, Figure 2 The diagram shows the forces acting on the first cam groove. The expression for the curve of the first cam groove is as follows:
[0013] r =R+Cα
[0014] Where r is the radius between each point on the first cam groove curve and the center of the groove plate, R is the base circle radius (set manually), C is a proportional constant (set manually), and α is the angle of rotation of the groove plate around the mandrel; r varies with α.
[0015] The axial thrust F generated by the fluid medium in the bellows causes the bellows to elongate axially, moving the first column 6 to the left and the second column 19 to the right. The axial thrust F acts on the first cam groove 17 through the first column, and the first cam groove has a restraining force on the movement of the first column. The magnitude of the restraining force is related to C.
[0016] When C is zero, the curve of the first cam groove is a circle. The axial thrust F of the fluid medium acts on the first cam groove and will not generate a tangential component force Fa. There is only a normal component force Fb. The normal component force Fb is equal in magnitude and opposite in direction to the axial thrust F. The groove plate cannot rotate and the column cannot move. The axial thrust F is absorbed by the first cam groove.
[0017] When C is not zero, the axial thrust F on the first cam groove can be decomposed into a normal component Fb and a tangential component Fa. The groove plate can rotate, and the column can move, meaning the compensator has thrust output. According to the law of reaction, the axial component Fz of the normal component Fb is opposite in direction to the axial thrust F. The thrust Fout output by the compensator is the difference between the axial component Fz and the axial thrust F.
[0018] That is, Fout = F - Fz
[0019] Choosing a smaller C value will make Fz close to but less than F, thus reducing the output thrust Fout.
[0020] The second cam groove is symmetrically arranged with the first cam groove and has the same structure. The second column and the second cam groove can also eliminate the axial thrust of the fluid medium in the bellows.
[0021] The principle of thermal expansion and contraction compensation is as follows: When the pipeline expands due to thermal expansion, it can be considered that an external force has intervened. The first and second bellows are compressed, the first and second columns move towards the mandrel, and the channel plate rotates. That is, the rotation of the channel plate is synchronized with the displacement of the pipeline. Most of the axial thrust generated by the fluid medium in the bellows is absorbed by the channel plate, and the thrust acting on the pipeline is very small. When the pipeline contracts due to thermal expansion, the first and second bellows are stretched, the first and second columns move away from the mandrel, and the channel plate rotates. Most of the axial thrust of the medium in the compensator is absorbed by the channel plate, and the thrust acting on the pipeline is very small.
[0022] To completely eliminate the axial thrust in the bellows, a butterfly spring 8 is provided between the flange 10 and the groove plate. A nut is screwed on the top of the mandrel, and the nut is in contact with the groove plate. When the nut is tightened, the groove plate presses against the butterfly spring, increasing the friction force for the rotation of the groove plate. If the friction force is equal to or greater than the tangential component force Fa, the axial thrust in the bellows will not cause the groove plate to rotate.
[0023] When the pipe expands or contracts due to heat, the stress in the pipe only needs to overcome the friction of the disc spring to achieve displacement.
Claims
1. A cam-balanced bellows compensator, comprising a first bellows (4), a second bellows (13), a second ring plate (11) welded between the first bellows (4) and the second bellows (13), a first ring plate (2) welded to the left end of the first bellows (4), and a third ring plate (15) welded to the right end of the second bellows (13), characterized in that, Multiple mandrels (9) are symmetrically welded on the outer circle of the second ring plate (11). The root of the mandrel has a flange (10). A groove plate (7) is fitted on the mandrel. A first cam groove (17) and a second cam groove (18) are symmetrically provided on the groove plate. A first column (6) is inserted in the first cam groove. The first column is fixedly connected to the first ring plate (2) through a first crossbar (5). A second column (12) is inserted in the second cam groove. The second column is fixedly connected to the third ring plate (15) through a second crossbar (14).
2. The cam-balanced bellows compensator according to claim 1, characterized in that, A butterfly spring (8) is provided between the flange (10) and the slot plate, and a nut is screwed on the top of the mandrel, with the nut in contact with the slot plate.