A low-frequency, multi-directional, broadband vibration absorber for pipelines

Abstract

The present invention discloses a low-frequency, multi-directional, broadband vibration absorber for pipelines, comprising a frame, an elastic element, a base mass, an additional mass, and a mounting fixture. The frame is in the shape of a ring, and a plurality of layers of periodically arranged circular holes are provided on the surface, and the diameters of the circular holes in each layer are different. The elastic element is composed of an inner ring, an outer ring, and a connecting beam. A connecting beam is provided between the inner ring and the outer ring. The outer ring is embedded in the circular hole of the frame and its size corresponds one-to-one to the circular hole on the frame. The base mass is detachably installed in the inner ring. The additional mass is attached to the base mass. By selectively installing the base mass and the additional mass, the resonant frequency of the vibration absorber can be adjusted to achieve regulation of the vibration absorption frequency band; by rotating the elastic element as a whole in the circular hole of the frame to change the bending vibration direction of the connecting beam, the vibration reduction direction of the vibration absorber and the coordinated control of multi-directional vibration can be achieved. The present invention has a compact structure, occupies a small space, is simple to process, has a low manufacturing cost, and has good low-frequency, multi-directional, broadband vibration reduction capabilities.

Description

Technical Field

[0001] The invention relates to the field of pipeline vibration noise control, in particular to a pipeline low-frequency multi-directional broadband vibration absorber. Background Art

[0002] Piping systems are often connected to various rotating and reciprocating equipment. When these devices are operating, the pipelines experience complex, low-frequency, broadband vibrations in multiple directions. While installing flexible pipes in series, elastic braces, or damping materials can reduce mid- and high-frequency vibrations to some extent, they are less effective at controlling low-frequency vibrations. Dynamic vibration absorbers offer excellent attenuation of low-frequency line spectra, and several published patents have demonstrated their use in pipeline vibration control.

[0003] Patent CN106122605A discloses a pipeline vibration absorber that uses an inner and outer double-ring design. The inner and outer rings are connected by a screw. The vibration absorption frequency can be adjusted by adjusting the stiffness of the spring wrapped around the screw and the mass of the slider mounted on the screw. Patent CN103470902A discloses a dynamic vibration absorber and design method for reducing pipeline vibration levels. The design includes 3-6 spring plates evenly distributed on the outside of a pair of pipe clamps. Additional mass blocks are installed at the ends of the spring plates. By changing the installation angle of the mass blocks on the spring plates, the natural frequency of each mass-spring plate is made different. The vibration absorber disclosed in the above patent has a certain frequency adjustment capability, but cannot flexibly and quickly adjust the vibration absorption direction.

[0004] Patent CN215488333U discloses a pipeline vibration absorber consisting primarily of an elastic component and a mass component. Both components are annular, maintaining consistent stiffness and mass in any radial direction. This ensures consistent vibration absorption performance in all directions along the pipeline path, thereby reducing linear vibrations along the pipeline path. While this invention can control multi-directional vibrations in the pipeline, the absorber's absorption frequency band is relatively narrow, significantly reducing its performance when the vibration frequency shifts. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-frequency, multi-directional, broadband vibration absorber for pipelines in response to the above situation. The absorber has a compact structure, occupies a small space, is simple to process, has a low manufacturing cost, and has good low-frequency, multi-directional, broadband vibration reduction capability.

[0006] The technical solutions of the present invention are as follows:

[0007] A low-frequency, multi-directional, broadband vibration absorber for a pipeline, comprising a frame, an elastic element, a base mass, an additional mass, and a mounting fixture;

[0008] The frame is annular, and has multiple layers of circular holes arranged periodically on its surface;

[0009] The elastic element includes an inner ring, an outer ring, and a connecting beam. A connecting beam is provided between the inner and outer rings. The outer ring is embedded in the circular hole of the frame and its size corresponds one-to-one with the circular hole on the frame. A basic mass is detachably installed in the inner ring, and the additional mass is attached to the basic mass. By selectively installing the basic mass and the additional mass, the resonance frequency of the vibration absorber can be adjusted to achieve regulation of the vibration absorption frequency band.

[0010] The bending vibration direction of the connecting beam can be changed by rotating the elastic element as a whole in the circular hole of the frame, thereby changing the effective action direction of the vibration absorber, thereby realizing the regulation of the vibration reduction direction of the vibration absorber and the coordinated control of multi-directional vibration;

[0011] A mounting fixture is provided in the middle of the frame, and the mounting fixture is used to fix the frame to the pipeline.

[0012] Furthermore, the diameters of the circular holes arranged on the surface of the frame are in the order of inner layer < outer layer < middle layer.

[0013] Furthermore, the inner ring is interference fit with a base mass of corresponding size, and the outer ring is interference fit with a frame circular hole of corresponding size.

[0014] Furthermore, the frame is made of aluminum material.

[0015] Furthermore, the elastic element is made of resin, nylon, plastic or thermoplastic TPU material.

[0016] Furthermore, the basic mass and the additional mass are made of metal, glass or ceramic materials.

[0017] Furthermore, the additional mass is in a cylindrical, square or other regular shape.

[0018] Furthermore, the mounting fixture includes an annular clamp, a connecting stud and a sleeve. The clamp is fixed to both sides of the frame through the connecting stud. The sleeve is arranged between the frame and the clamp to reserve installation space for the resonance unit.

[0019] Furthermore, the mounting fixture is made of steel or aluminum.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) By attaching additional masses of varying sizes to the base mass, the mass parameters of the resonant units can be detuned. After introducing the detuning parameters, the resonant frequencies of the resonant units are distributed over a wide frequency range, thereby forming a local resonant mode group. The resonant units have impedance peaks within the local resonant mode group. By adjusting the parameters, the absorber impedance can be stabilized at a high amplitude, thereby achieving good broadband vibration reduction capabilities.

[0022] (2) Resonant units of appropriate size are installed in the circular holes of each layer. Each resonant unit has an elastic element and a base mass that matches its own size, which makes the resonant units of each layer have different resonant frequencies when not detuned. After the detuning parameters are introduced, the local resonant mode groups formed by the resonant units of each layer are distributed in different frequency bands. By properly designing the parameters of the resonant units, the different local resonant mode groups can be controlled to be continuously distributed in the frequency domain, thereby further widening the vibration absorption frequency band.

[0023] (3) The effective vibration reduction direction of the resonant unit is the bending vibration direction of the connecting beam. Due to the interference fit between the outer ring of the elastic element and the circular hole of the frame, the elastic element can be flexibly rotated to a suitable angle, thereby changing the bending vibration direction of the connecting beam and realizing rapid regulation of the vibration reduction direction. In actual use, the number of resonant units in the corresponding direction can be reasonably allocated according to the vibration magnitude of the pipeline in different directions. The rotation angle of the resonant unit can also be controlled so that it has a reaction force component in different vibration directions of the pipeline, thereby realizing coordinated control of multi-directional vibration of the pipeline.

[0024] (4) The present invention has a compact structure, occupies a small space, is simple to process, and has a low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 This is a structural front view of the present invention;

[0027] Figure 3 Schematic diagram of the installation fixture structure;

[0028] Figure 4 It is the main view of the elastic element;

[0029] Figure 5 is a top view of the elastic element;

[0030] Figure 6 Schematic diagram of the vertical vibration absorption effect of the present invention;

[0031] Figure 7 It is a schematic diagram of the lateral vibration absorption effect of the present invention.

[0032] The meanings of the reference numerals in the accompanying drawings are as follows:

[0033] 1. Frame, 1-1. Inner circular hole, 1-2. Middle circular hole, 1-3. Outer circular hole, 2. Elastic element, 2-1. Large elastic element, 2-2. Medium elastic element, 2-3. Small elastic element, 3. Foundation mass, 3-1. Large foundation mass, 3-2. Medium foundation mass, 3-3. Small foundation mass, 4. Additional mass, 5. Mounting fixture, 6. Ring hoop, 7. Connecting stud, 8. Sleeve, 9. Inner ring, 10. Outer ring, 11. Connecting beam. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. The accompanying drawings described below are intended to provide a further understanding of the present invention and are not intended to limit the present invention.

[0035] Reference Figures 1 to 5 The technical solution of the pipeline low-frequency multi-directional broadband vibration absorber of the present invention includes a frame 1, an elastic element 2, a basic mass 3, an additional mass 4 and a mounting fixture 5.

[0036] The frame 1 is annular and has multiple layers of periodically arranged circular holes on its surface. The positions of the circular holes can be divided into inner circular holes 1-1, middle circular holes 1-2 and outer circular holes 1-3 according to the diameter of the central reference circle.

[0037] The elastic element 2 comprises an inner ring 9, an outer ring 10, and a connecting beam 11. The connecting beam 11 is disposed between the inner and outer rings 9 and 10. The outer ring 10 is inserted into the circular hole of the frame 1 and its dimensions correspond one-to-one with the circular hole of the frame 1. A base mass 3 is detachably mounted within the inner ring 9, and the additional mass 4 is affixed to the base mass 3. By selectively mounting the base mass 3 and the additional mass 4, the resonant frequency of the vibration absorber can be adjusted, thereby achieving control over the vibration absorption frequency band.

[0038] The bending vibration direction of the connecting beam 11 can be changed by rotating the elastic element 2 as a whole in the circular hole of the frame 1, thereby changing the effective action direction of the vibration absorber, thereby achieving the regulation of the vibration reduction direction of the vibration absorber and the coordinated control of multi-directional vibration;

[0039] A mounting fixture 5 is provided in the middle of the frame 1 , and the mounting fixture 5 is used to fix the frame 1 to the pipeline.

[0040] The diameters of the circular holes arranged on the surface of the frame 1 are in the order of inner layer < outer layer < middle layer.

[0041] The elastic element 2 is categorized by size into a large elastic element 2-1, a medium elastic element 2-2, and a small elastic element 2-3. The base mass 3 is categorized by size into a large base mass 3-1, a medium base mass 3-2, and a small base mass 3-3. The inner ring 9 of the elastic element 2 is interference-fitted with the base mass 3 of corresponding size, while the outer ring 10 is interference-fitted with the circular hole of the frame 1 of corresponding size.

[0042] The frame 1 is made of aluminum material, which has the characteristics of low density and high strength, and can reduce the overall weight of the structure while avoiding large deformation of the structure.

[0043] The elastic element 2 is made of resin, nylon, plastic or thermoplastic TPU material.

[0044] The basic mass 3 and the additional mass 4 are made of metal, glass or ceramic materials.

[0045] The additional mass 4 is cylindrical, square or other regular shapes.

[0046] The mounting fixture 5 includes an annular clamp 6, a connecting stud 7 and a sleeve 8. The clamp 6 is fixed to both sides of the frame 1 through the connecting stud 7. The sleeve 8 is arranged between the frame 1 and the clamp 6 to reserve installation space for the resonance unit.

[0047] The installation fixture 5 is made of steel or aluminum.

[0048] The specific method of use of the present invention is as follows:

[0049] Step 1: Obtain the vibration characteristics of the pipeline in different directions. Perform vibration testing on the target pipeline to extract the pipeline's multi-directional vibration signals and determine the frequencies and locations where vibration is most pronounced in different directions. When using a pipeline vibration absorber, adjust the absorber's effective vibration reduction frequency band to the frequency range of the pipeline to be dampened. Install the absorber in a location where vibration is most pronounced to achieve optimal vibration control.

[0050] Step 2: Determine the parameters of the frame 1, elastic element 2, and foundation mass 3. When the additional mass 4 is not attached, the resonant units of each layer are not detuned in theory. At this time, the resonant frequency f of the resonant unit satisfies the relationship between the equivalent stiffness k of the connecting beam and the foundation mass m. When designing parameters, the resonant frequency of each layer of resonance unit should be distributed near the frequency at which the pipeline needs to be damped.

[0051] Step 3: Determine the size of the additional mass 4 of each resonant unit. When the detuning parameter is introduced, the resonant frequency of each resonant unit is distributed over a wide frequency range, thus forming a local resonant mode group. By changing the size of the additional mass 4, the mass detuning intensity of each layer of resonant unit can be adjusted, thereby controlling the resonant frequency distribution range. The mass detuning intensity of each layer of resonant unit can be calculated as follows: Where N is the number of resonant units in each layer, m i is the vibration-absorbing mass of each resonant unit layer, and μ is the average vibration-absorbing mass of each resonant unit layer. When determining the value of the additional mass 4, the local resonant mode groups formed by each resonant unit layer should be distributed as continuously as possible to achieve the goal of widening the vibration absorption frequency band. Furthermore, the detuning strength should be appropriately selected. Too low a detuning strength will cause the local resonant mode groups to be distributed over a narrow frequency band, resulting in a less pronounced vibration absorption band widening. Too high a detuning strength will increase the spacing between the resonant frequencies, which is not conducive to stable vibration absorption.

[0052] Step 4: Determine the rotation angle of the resonant unit based on the vibration characteristics of the pipeline in different directions. When the pipeline vibrates significantly in a single direction, all elastic elements 2 can be rotated to the same position so that the bending vibration direction of the connecting beam 11 aligns with the pipeline vibration direction, thereby maximizing the vibration reduction capability of the resonant unit. When the pipeline vibrates significantly in multiple directions, one method of using the present invention is to reasonably allocate the number of resonant units in the corresponding directions based on the amplitude of the pipeline vibration in each direction. Generally speaking, the greater the vibration amplitude, the more resonant units need to be allocated. Another method is to rotate the elastic element 2 to an inclined position so that the bending vibration direction of the connecting beam 11 maintains a certain angle with the pipeline vibration direction. This ensures that the resonant unit has a reaction force component in different vibration directions of the pipeline, achieving coordinated control of the pipeline's multi-directional vibration. In addition, when the pipeline vibrates significantly in multiple different frequency bands, multiple pipeline vibration dampers with different vibration reduction frequency bands can be used in combination to further reduce the overall vibration level of the pipeline.

[0053] To further verify the vibration reduction effect of the present invention, a short pipe was selected for testing. The pipe parameters were as follows: length L = 150 mm, outer diameter D = 80 mm, wall thickness t = 5 mm, material was 6061 aluminum alloy, and rubber isolators were used for elastic support below the pipe.

[0054] In this embodiment, the frame 1 is machined with three layers of circular holes of varying diameters. The inner diameters of the inner, middle, and outer holes are 15mm, 17mm, and 16mm, respectively. Each layer contains 10 holes, resulting in a total of 30 resonant units in the pipeline low-frequency, multi-directional, broadband vibration absorber. The elastic elements 2 are made of resin. The inner rings 9 of the large, medium, and small elastic elements 2-1, 2-2, and 2-3 have inner diameters of 9mm, 8mm, and 7mm, respectively, and outer diameters of 11mm, 10mm, and 9mm, respectively. The outer rings 10 have inner diameters of 15mm, 14mm, and 13mm, respectively, and outer diameters of 17mm, 16mm, and 15mm, respectively. The connecting beams 11 are all 2mm long, 1mm thick, and 2.4mm, 2mm, and 1.6mm wide, respectively. The cylindrical base mass 3 is made of high-purity tungsten, with a height of 10mm. The base diameters of the base masses 3 of varying sizes match the inner diameter of the inner ring 9 of the elastic element 2. The additional mass 4 is made of stainless steel circular sheets. In this embodiment, the additional mass 4 has three different sizes, which match the corresponding sizes of the basic mass 3. The thickness of the additional mass 4 attached to each layer of the resonant unit increases in equal intervals from 0 to 9 mm in the clockwise direction.

[0055] During the test, a hammer was used to apply vertical and lateral excitations to one end of the pipeline, comparing the vibration characteristics of the pipeline before and after the vibration absorber was installed. To better observe the vibration absorption effect of the present invention, the elastic elements 2 were all rotated to the horizontal position during vertical excitation and to the vertical position during lateral excitation. This maximized the effective effect of the resonant unit under different excitation directions.

[0056] Figure 6 、 Figure 7 The vertical and lateral vibration absorption effects of the low-frequency multi-directional broadband vibration absorber of the pipeline are shown respectively. In the analysis, the basic structure consisting of pipeline + mass block is selected for comparison. The mass block used is equivalent to the mass of the vibration absorber. Figure 6 and Figure 7 It can be seen that after installing the low-frequency, multi-directional, broadband vibration absorber, the pipeline vibration is well controlled. Within the design frequency band of the vibration absorber, 80Hz-120Hz, the pipeline vibration response fluctuates significantly. Under vertical excitation, the foundation structure's peak value at 94.5Hz is 127.0dB. After installing the pipeline vibration absorber, the peak value drops to 115.0dB, and the actual effective vibration reduction bandwidth of the vibration absorber is approximately 26.5Hz. Under lateral excitation, the foundation structure's peak value at 74.0Hz is 142.4dB. After installing the pipeline vibration absorber, the peak value drops to 123.4dB, and the actual effective vibration reduction bandwidth of the vibration absorber is approximately 34.0Hz. The present invention demonstrates excellent low-frequency, multi-directional, broadband vibration reduction capabilities.

[0057] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art should understand that the technical method of the present invention may be modified and varied. However, any modification, equivalent substitution, improvement, etc. made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A low-frequency, multi-directional, broadband vibration absorber for pipelines, characterized in that: Includes frame, elastic elements, base mass, additional mass and mounting fixtures; The frame is annular, and has multiple layers of circular holes arranged periodically on its surface; The elastic element includes an inner ring, an outer ring, and a connecting beam. A connecting beam is provided between the inner and outer rings. The outer ring is embedded in the circular hole of the frame and its size corresponds one-to-one with the circular hole on the frame. A basic mass is detachably installed in the inner ring, and the additional mass is attached to the basic mass. By selectively installing the basic mass and the additional mass, the resonance frequency of the vibration absorber can be adjusted to achieve regulation of the vibration absorption frequency band. The bending vibration direction of the connecting beam can be changed by rotating the elastic element as a whole in the circular hole of the frame, thereby changing the effective action direction of the vibration absorber, thereby realizing the regulation of the vibration reduction direction of the vibration absorber and the coordinated control of multi-directional vibration; A mounting fixture is provided in the middle of the frame, and the mounting fixture is used to fix the frame to the pipeline.

2. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The diameters of the circular holes arranged on the surface of the frame are in the order of inner layer < outer layer < middle layer.

3. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The inner ring is interference-fitted with a base mass of corresponding size, and the outer ring is interference-fitted with a frame circular hole of corresponding size.

4. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The frame is made of aluminum material.

5. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The elastic element is made of resin, nylon, plastic or thermoplastic TPU material.

6. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The basic mass and the additional mass are made of metal, glass or ceramic materials.

7. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The additional mass is in a cylindrical, square or other regular shape.

8. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The mounting fixture includes an annular hoop, a connecting stud and a sleeve. The hoop is fixed to both sides of the frame through the connecting stud. A sleeve is provided between the frame and the hoop to reserve installation space for the resonance unit.

9. The pipeline low-frequency multi-directional broadband vibration absorber according to claim 1, characterized in that: The installation fixture is made of steel or aluminum.

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