Magnetic force damping dynamic vibration absorber for pipelines

Abstract

The application discloses a pipeline magnetic force damping dynamic vibration absorber, which comprises a shell, a clamp, a vibration absorbing mechanism and a magnetic force damping mechanism arranged in the shell, the vibration absorbing mechanism comprises a sliding rod fixed on the shell and a mass block slidingly arranged on the sliding rod, the magnetic force damping mechanism comprises a conductor plate arranged on the mass block and a magnet fixed on the shell, and the magnet is arranged correspondingly to the conductor plate. The material of the conductor plate is a metal with good conductivity, preferably copper. The pipeline magnetic force damping dynamic vibration absorber has the advantages that it does not need to be rooted in other structures except the pipeline, and has low requirement on installation space; and the magnetic force damping structure is a non-contact structure, so that the damping effect is not attenuated or the service life is not shortened due to friction and other factors, compared with other contact damping structures.

Description

Technical Field

[0001] This invention belongs to the field of industrial pipeline vibration control, specifically relating to a magnetic damping dynamic vibration absorber for pipelines. Background Technology

[0002] Pipeline vibration is a common problem in nuclear power, thermal power, petrochemical and aerospace industries. It often leads to damage to the pipeline itself, pipeline connecting equipment, pipeline accessories and pipeline supports, and sometimes even requires shutdown for maintenance, resulting in significant economic losses and seriously affecting safe production.

[0003] Conventional solutions for pipeline vibration mitigation mainly involve altering the pipeline layout and adding restraint supports, but these methods suffer from large-scale modifications and difficulties in securing the supports. Installing dynamic vibration absorbers on the pipeline is another vibration reduction method that requires no additional support locations and has low space requirements. The advantage of dynamic vibration absorbers is that they transfer the pipeline's vibration energy to their own mass; however, existing dynamic vibration absorbers cannot effectively dissipate this vibration energy. Summary of the Invention

[0004] In view of this, in order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a magnetic damping dynamic vibration absorber for pipelines, which can realize the transfer and dissipation of pipeline vibration energy, thereby reducing pipeline vibration.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A magnetically damped dynamic vibration absorber for pipelines includes a housing, a clamp, a vibration absorption mechanism and a magnetic damping mechanism disposed within the housing. The vibration absorption mechanism includes a slide rod fixed to the housing and a mass block slidably disposed on the slide rod. The magnetic damping mechanism includes a conductor plate disposed on the mass block and a magnet fixed to the housing, the magnet being positioned corresponding to the conductor plate. The conductor plate is made of a highly conductive metal, preferably copper. The distance between the conductor plate and the magnet is generally set to 3mm to 6mm.

[0007] The working principle of a magnetic damping mechanism is as follows: when a closed conductor moves relative to a magnetic pole, electromagnetic resistance is generated between them, hindering the relative motion. Specifically, when a closed conductor moves and cuts magnetic field lines with a magnetic pole, the magnetic flux penetrating the closed conductor changes, generating an induced current, or motional current; the magnetic field generated by this current hinders the relative motion between the two.

[0008] According to some preferred embodiments of the invention, the sliding rod extends perpendicularly to the extension direction of the pipe; the sliding rod passes through the mass block. That is, the direction of movement of the mass block is perpendicular to the extension direction of the pipe.

[0009] According to some preferred embodiments of the invention, the slide bar includes a smooth section in the middle and threaded sections at both ends. The smooth section is used for sliding of the mass block, and the ends of the threaded sections away from the smooth section are connected to the housing. The two ends of the slide bar are fixed to the housing, and the smooth section is located in the middle of the slide bar. When the pipe vibrates, the mass block moves on the smooth section.

[0010] According to some preferred embodiments of the present invention, a nut is provided on the threaded section, and an elastic element is provided between the nut and the mass block. That is, one end of the elastic element acts on the nut, and the other end acts on the mass block.

[0011] According to some preferred embodiments of the invention, the mass block is provided with two sliding rods; elastic elements are provided on both sides of the mass block. When the pipeline vibrates, the mass block moves on the smooth section, and by placing the mass block between the elastic elements on both sides, the mass block is confined on the smooth section to absorb vibration.

[0012] According to some preferred embodiments of the present invention, two conductor plates are provided on the mass block, and the arrangement direction of the two conductor plates is the same as the extension direction of the slide bar; two magnets are provided on the housing corresponding to the conductor plates.

[0013] According to some preferred embodiments of the present invention, a horizontal plate is provided on the upper part of the housing, and the magnet is disposed on the horizontal plate.

[0014] According to some preferred embodiments of the invention, a vertical plate is provided on the side of the housing, and the end of the slide rod is connected to the vertical plate. That is, in some embodiments, the housing is hollowed out, having a cavity for accommodating the vibration absorption mechanism and the magnetic damping mechanism, a horizontal plate for fixing the magnet at the top, and vertical plates for fixing the slide rod on the side. Preferably, the vertical plate has a groove extending through its thickness direction. The groove allows adjustment of the slide rod's height, enabling the groove and fasteners to fix the slide rod in a suitable position, facilitating adjustment of the distance between the conductor plate and the magnet. The hollowed-out design of the housing minimizes the overall mass of the dynamic vibration absorber, thereby reducing the impact on the pipe's inherent modes.

[0015] According to some preferred embodiments of the present invention, the conductor plate is fixed to the upper surface of the mass block by fasteners, and insulating pads are respectively provided between the conductor plate, the fasteners, and the mass block. The insulating pads can reduce the influence of metal structures such as the mass block on the magnetic damping structure.

[0016] According to some preferred embodiments of the invention, the clamp is used to fix the dynamic vibration absorber to the pipe, the clamp includes an upper clamp and a lower clamp, the top of the upper clamp being fixedly connected to the bottom of the housing.

[0017] According to some preferred embodiments of the present invention, the mass m of the mass block, the spring stiffness k, and the magnetic damping coefficient c in the dynamic vibration absorber are calculated by the following formulas:

[0018] m = μM

[0019]

[0020]

[0021] In the formula, M is the equivalent mass of the main vibration system; K is the equivalent stiffness of the main vibration system; and μ is the mass ratio of the vibration absorber to the main vibration system.

[0022] According to some preferred embodiments of the present invention, the magnetic damping mechanism is determined according to the following formula:

[0023]

[0024] In the formula, 'a' represents the magnetic pole area of ​​the magnet, in meters (m²). 2 ; t is the thickness of the conductor plate, in meters; B is the magnetic flux density, in volts (T); ρ is the conductor resistance, in ohms (Ω); K m For the conductor area A (m 2 ) and magnetic pole area a(m 2 The coefficient is determined by the ratio of ).

[0025] Due to the adoption of the above technical solutions, the advantages of this invention compared with the prior art are as follows: First, the magnetic damping dynamic vibration absorber for pipelines of this invention does not require anchoring in any structure other than the pipeline, thus requiring less installation space; second, the magnetic damping structure is a non-contact structure, which, compared with other contact damping, will not cause the damping effect to decrease or the lifespan to be shortened due to factors such as friction. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a three-dimensional structural schematic diagram of a magnetic damping dynamic vibration absorber for pipelines according to a preferred embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the cross-sectional structure of a magnetically damped dynamic vibration absorber for pipelines according to a preferred embodiment of the present invention;

[0029] Figure 3This is a schematic diagram illustrating the principle of the magnetic damping mechanism of the magnetic damping dynamic vibration absorber for pipelines according to a preferred embodiment of the present invention.

[0030] In the attached diagram: lower clamp-1, upper clamp-2, housing-3, horizontal plate-31, vertical plate-32, sliding groove-33, nut-4, sliding rod-5, threaded section-51, elastic element-6, conductor plate-7, magnet-8, mass block-9, fastener-10. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] See Figure 1-2 As shown, the magnetically damped dynamic vibration absorber for pipelines in this embodiment includes a housing 3, clamps, a vibration absorption mechanism, and a magnetic damping mechanism disposed within the housing 3. The surface of the housing 3 is hollowed out, and it has cavities for accommodating the vibration absorption mechanism and the magnetic damping mechanism. The hollowed-out design of the housing can minimize the overall mass of the dynamic vibration absorber, thereby reducing its impact on the natural modes of the pipeline. The clamps are used to fix the dynamic vibration absorber to the pipeline, and the clamps include an upper clamp 2 and a lower clamp 1, with the top of the upper clamp 2 fixedly connected to the bottom of the housing 3. The vibration absorption mechanism transfers the vibration of the pipeline to the mass block 9, and the energy is dissipated through the magnetic damping mechanism.

[0033] The vibration damping mechanism includes a slide rod 5 fixed to the housing 3, a mass block 9 slidably disposed on the slide rod 5, and elastic elements 6 located on both sides of the mass block 9. In this embodiment, the elastic element 6 is preferably a spring, which is sleeved on the slide rod 5.

[0034] Two sliding rods 5 are provided on the mass block 9, and the extension direction of the sliding rods 5 is perpendicular to the extension direction of the pipe; that is, the movement direction of the mass block 9 is perpendicular to the extension direction of the pipe. The sliding rods 5 pass through the mass block 9, and a sliding hole is opened in the mass block 9 for assembly with the sliding rods 5. The sliding rod 5 includes a smooth section in the middle and threaded sections 51 at both ends. The smooth section is used for the mass block 9 to slide, and the end of the threaded section 51 away from the smooth section is connected to the housing 3. The two ends of the sliding rod 5 are fixed to the housing 3, and the smooth section is located in the middle position of the sliding rod 5. When the pipe vibrates, the mass block 9 moves on the smooth section.

[0035] A nut 4 is installed on the threaded section 51, and an elastic element 6 is positioned between the nut 4 and the mass block 9. That is, one end of the elastic element 6 acts on the nut 4, and the other end acts on the mass block 9. Elastic elements 6 are installed on both sides of the mass block 9, fastened around its perimeter. When the pipeline vibrates, the mass block 9 moves on the smooth section. By positioning the mass block 9 between the elastic elements 6 on both sides, it is confined on the smooth section to absorb vibration.

[0036] The magnetic damping mechanism includes a conductor plate 7 mounted on a mass block 9 and magnets 8 fixed to a housing 3, with the magnets 8 corresponding to the conductor plate 7. The conductor plate 7 is made of a highly conductive metal, preferably copper. Two conductor plates 7 are mounted on the mass block 9, and their arrangement direction is the same as the extension direction of the slide bar 5. Two magnets 8 are mounted on the housing 3 corresponding to the conductor plates 7. The conductor plates 7 are fixed to the upper surface of the mass block 9 by fasteners 10, and insulating pads are provided between the conductor plates 7, the fasteners 10, and the mass block 9. The insulating pads reduce the influence of the mass block and other metal structures on the magnetic damping structure.

[0037] A horizontal plate 31 is provided on the upper part of the housing 3, and the magnet 8 is mounted on the horizontal plate 31. A vertical plate 32 is provided on the side of the housing 3, and the end of the slide rod 5 is connected to the vertical plate 32. That is, the top of the housing 3 has a horizontal plate 31 for fixing the magnet 8, and the side has a vertical plate 32 for fixing the slide rod 5. In this embodiment, the vertical plate 32 has a groove 33 extending through its thickness direction, and the extension direction of the groove 33 is the same as the extension direction of the vertical plate 32. The groove 33 can adjust the height of the slide rod 5 so that the groove 33 and the fastener 10 can fix the slide rod 5 in a suitable position, which facilitates the adjustment of the distance between the conductor plate 7 and the magnet 8. Generally, the distance between the conductor plate and the magnet is set to 3mm to 6mm.

[0038] In this embodiment, the parameters of the components in the magnetic damping dynamic vibration absorber for pipelines are determined by the following formulas, which must satisfy the optimal harmony condition and the optimal damping condition, as detailed below:

[0039] 1. Optimal Cohomology

[0040]

[0041] 2. Optimal damping ratio

[0042]

[0043] 3. The maximum amplitude ratio that satisfies the above conditions

[0044]

[0045] In the formula, γ is the ratio of the natural angular frequency of the vibration absorber to that of the main vibration system (the pipe being treated); μ is the mass ratio of the vibration absorber to that of the main vibration system; ζopt X represents the optimal damping ratio of the dynamic vibration absorber; X represents the maximum vibration deformation (m) of the main vibration system; X represents... st The static deformation (m) of the main vibration system.

[0046] After determining the mass ratio μ, the design formulas for the three elements of the dynamic vibration absorber (mass of the mass block, spring stiffness, and damping coefficient) are as follows:

[0047] 1. The mass m of the mass block in the dynamic vibration absorber

[0048] m=μM(kg) (4)

[0049] 2. Spring stiffness k in a dynamic vibration absorber

[0050]

[0051] 3. The magnetic damping coefficient c of the magnetic damping structure

[0052]

[0053] In the formula, M is the equivalent mass (kg) of the main vibration system; K is the equivalent stiffness (N / m) of the main vibration system.

[0054] Conductor plate design formula:

[0055] The basic structure of magnetic damping is as follows: Figure 3 As shown, it mainly consists of a permanent magnet (magnet) 8 and a conductor (conductor plate 7). The magnetic damper has good linearity, is not easily affected by temperature, has no friction caused by the mechanical foundation, and is easy to install. When the conductor plate 7 moves transversely in the magnetic field generated by the permanent magnet 8, eddy currents will be generated in the conductor, thus generating a magnetic braking force in the opposite direction to the direction of motion, i.e., magnetic damping force. The damping coefficient c of the magnetic damper is calculated by equation (7).

[0056]

[0057] In the formula, 'a' represents the magnetic pole area, in meters (m²). 2 ; t is the thickness of the conductor plate, in meters; B is the magnetic flux density, in volts (T); ρ is the conductor resistance, in ohms (Ω); K m For the conductor area A (m 2 ) and magnetic pole area a(m 2 The coefficient determined by the ratio of A / a can be taken as K when A / a is much greater than 1. m =0.5, when A / a = 4, K m =0.45.

[0058] The modal parameters of the main vibration system in this embodiment are shown in Table 1. The optimized design parameters of the dynamic vibration absorber shown in Table 2 can be obtained by formulas (1) to (6). According to the optimized design parameters, a mass block and spring that meet the requirements are selected and configured, and a magnetic damping structure that meets the damping coefficient requirements is configured according to formula (7).

[0059] Table 1 Modal parameters of the main vibration system

[0060] Natural frequency / Hz <![CDATA[Natural angular frequency / rad.s -1 > Equivalent mass / kg <![CDATA[Equivalent stiffness / N.m -1 > 19.5 122.4 27.0 404938.4

[0061] Table 2 Optimized design parameters for dynamic vibration absorbers

[0062] <![CDATA[Natural angular frequency / rad.s -1 > Mass of mass block / kg <![CDATA[Stiffness / N.m -1 > <![CDATA[Damping coefficient / N.s.m -1 > 116.0 1.5 20173.7 48.9

[0063] The magnetic damping dynamic vibration absorber for pipeline vibration provided by this invention can transfer and dissipate pipeline vibration energy, thereby reducing pipeline vibration. It effectively addresses the problem of high vibration in industrial pipelines, and is easy to install with low construction costs. It can effectively ensure the safe operation of industrial pipelines, reduce unplanned downtime for maintenance, and has high economic benefits.

[0064] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A magnetically damped dynamic vibration absorber for a pipe, characterized by The power vibration absorber comprises a shell, a clamp, a vibration absorbing mechanism arranged in the shell and a magnetic damping mechanism, the vibration absorbing mechanism comprises a slide rod fixed on the shell and a mass block slidingly arranged on the slide rod, and the magnetic damping mechanism comprises a conductor plate arranged on the mass block and a magnet fixed on the shell, and the magnet is arranged corresponding to the conductor plate; The extending direction of the slide rod is perpendicular to the extending direction of the pipeline; the slide rod penetrates the mass block; the slide rod comprises a smooth section in the middle and threaded sections at two ends, the smooth section is used for sliding of the mass block, and the threaded sections are connected to the shell away from the ends of the smooth section; a nut is arranged on the threaded section, and an elastic member is arranged between the nut and the mass block; Two conductor plates are arranged on the mass block, and the arrangement direction of the two conductor plates is the same as the extending direction of the slide rod; two magnets are arranged on the shell corresponding to the conductor plates; an upper portion of the shell is provided with a horizontal plate, and the magnets are arranged on the horizontal plate; The conductor plates are fixed on the upper surface of the mass block through fasteners, and insulating pads are arranged between the conductor plates, the fasteners and the mass block respectively; The clamp is used for fixing the power vibration absorber on the pipeline, and the clamp comprises an upper clamp and a lower clamp, and the top of the upper clamp is fixedly connected to the bottom of the shell.

2. The dynamic absorber of claim 1, wherein Two slide rods are arranged on the mass block; elastic members are arranged on the two sides of the mass block.

3. The dynamic absorber of claim 1, wherein A vertical plate is arranged on the side of the shell, and the end of the slide rod is connected to the vertical plate.

4. The dynamic absorber of claim 1, wherein The mass m, the spring stiffness k and the magnetic damping coefficient c of the mass block in the power vibration absorber are calculated through the following formulas respectively: m=μM In the formula, M is the equivalent mass of the main vibration system; K is the equivalent stiffness of the main vibration system; μ is the mass ratio of the vibration absorber to the main vibration system.

5. The power absorber according to claim 1, wherein The magnetic damping mechanism is determined according to the following formula: In the formula, a is the pole area of the magnet, in m2 2 ; t is the thickness of the conductor plate, in meters; B is the magnetic flux MI, in Tesla; ρ R = resistance of conductor, in ohms; K m R = resistance of conductor, in ohms; K 2 R = resistance of conductor, in ohms; K 2 R = resistance of conductor, in ohms; K

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