Dynamic vibration absorber for small-diameter natural gas pipeline

Abstract

The invention belongs to the technical field of vibration control of fluid pipelines, and particularly relates to a dynamic vibration absorber for a small-diameter natural gas pipeline, which comprises a connecting bolt, a connecting joint, a rubber elastic body, a base and a mass block, the connecting joint is fixedly connected with the center of the lower bottom surface of the base, and the rubber elastic body is fixed with the upper surface of the base; the mass block is located on the upper surface of the rubber elastic body and fixed to the base through a connecting bolt. The dynamic vibration absorber for the small-diameter natural gas pipeline is convenient to install, and limitation of terrains and space does not need to be considered; and the effect is remarkable, pipeline vibration can be reduced by 50%, and the service life is prolonged by more than 5 times.

Description

Technical Field

[0001] This invention belongs to the field of vibration control technology for fluid pipelines, and specifically relates to a dynamic vibration absorber for small-diameter natural gas pipelines. Background Technology

[0002] With the continuous expansion and rapid development of urban construction, the consumption of natural gas has continued to grow rapidly, resulting in a significant increase in the daily processing and supply of natural gas at some stations. Due to the throttling effect at the throttling parts or pressure regulating branches of the gas transmission pipeline, flow-induced vibration occurs, causing the gas transmission pipeline to generate significant vibration and noise. The small-diameter thin-walled pipelines connected to it are more prone to excessive vibration due to their large length-to-diameter ratio. This will exacerbate fatigue damage to the pipe wall material, causing local fatigue fracture, resulting in gas leakage and safety accidents.

[0003] For small-diameter pipes, vibration damping supports are usually installed to form a stable support connection with the ground, thereby suppressing excessive vibration of the small-diameter pipes. However, this simple vibration damping method of adding supports is limited by space in many densely packed pipeline conditions and cannot be installed. Summary of the Invention

[0004] The purpose of this invention is to provide a dynamic vibration absorber for small-diameter natural gas pipelines to solve the above-mentioned technical problems.

[0005] The technical solution adopted in this invention is as follows:

[0006] A dynamic vibration absorber for small-diameter natural gas pipelines includes connecting bolts, a connecting joint, a rubber elastomer, a base, and a mass block. The connecting joint is fixedly connected to the center of the lower bottom surface of the base, the rubber elastomer is fixed to the upper surface of the base, and the mass block is located on the upper surface of the rubber elastomer. The mass block and the rubber elastomer are fixed together by connecting bolts.

[0007] Furthermore, the dynamic vibration absorbers are provided in multiple sets, with two in each set. Connectors are fixed on the natural gas pipeline, and the two dynamic vibration absorbers in each set are fixed to both ends of the connectors through connecting joints.

[0008] Furthermore, the connector includes an upper component and a lower component. The middle section of both the upper and lower components is a semi-circular arc plate that fits into the natural gas pipeline, and the two ends are straight plates. The upper and lower components are fixed together through threaded holes opened on the straight plates.

[0009] Furthermore, the mass block has a circular barrel structure with a hollow interior, and a rubber gasket is provided between the connecting bolt and the mass block.

[0010] Furthermore, a removable cover plate is provided at the upper opening of the mass block of the circular barrel structure.

[0011] Furthermore, a metal shell is provided above the base, and the mass block and the rubber elastomer are both placed inside the metal shell.

[0012] Furthermore, the mass ratio of the mass block to the main vibration system is 0.39 to 0.44.

[0013] The beneficial technical effects of the present invention are as follows:

[0014] The dynamic vibration absorber for small-diameter natural gas pipelines provided by this invention is easy to install, without considering terrain and space limitations; it is highly effective, and the optimal damping ratio can be obtained through pipeline vibration measurement and calculation. The dynamic vibration absorber designed and manufactured according to the above parameters can reduce pipeline vibration by more than 50%. It extends the service life of pipelines by more than 5 times, reduces the risk of safety leaks, and significantly saves maintenance costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the connection of the dynamic vibration absorber of the present invention on the pipeline;

[0016] Figure 2 This is a schematic diagram of the internal structure of a dynamic vibration absorber;

[0017] Figure 3 This is a force analysis diagram of the dynamic vibration absorber model.

[0018] Among them, 1-metal shell, 2-mass block, 3-connecting bolt, 4-rubber gasket, 5-rubber elastomer, 6-base, 7-connecting joint, 8-connecting piece. Detailed Implementation

[0019] 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 are within the scope of protection of the present invention.

[0020] Example:

[0021] like Figure 2 As shown, a dynamic vibration absorber for small-diameter natural gas pipelines includes a metal shell 1, connecting bolts 3, connecting joints 7, a rubber elastomer 5, a base 6, and a mass block 2. The connecting joint 7, rubber elastomer 5, and base 6 are integrally formed by compression molding and vulcanization. The mass block 2 is fixed to the rubber elastomer 5 by the connecting bolts 3, and a rubber gasket 4 is provided between the connecting bolts 3 and the mass block 2. The metal shell 1 is positioned above the base 6, and both the mass block 2 and the rubber elastomer 5 are housed inside the metal shell 1.

[0022] Mass block 2 is a circular barrel structure with a hollow interior, and rubber elastomer 5 is also hollow inside.

[0023] like Figure 1 As shown, the dynamic vibration absorber is provided in multiple sets, with two in each set. A connector 8 is fixed on the natural gas pipeline. The two dynamic vibration absorbers in each set are fixed to both ends of the connector 8 through the connecting joint 7. The connector 8 includes an upper component and a lower component. The middle section of the upper and lower components are semi-circular arc plates that fit against the natural gas pipeline, and the two ends are straight plates. The upper and lower components are fixed together through threaded holes opened on the straight plates.

[0024] The rubber elastomer 5 provides elastic stiffness and damping; the mass block 2 is equivalent to the mass of the vibration system. In the entire dynamic vibration absorber system, the rubber elastomer 5 acts as a spring and a damper. Therefore, it is necessary to perform finite element simulation analysis on the stiffness value and repeatedly adjust the structure and material hardness of the rubber part to make the stiffness of the vibration absorber reach the design value.

[0025] Invention principle:

[0026] like Figure 3 As shown, the dynamic vibration absorber model neglects damping in the main vibration system, and the system's differential equation of motion is:

[0027]

[0028] (1)

[0029] In the formula: M and m are the masses of the main vibration system and the dynamic vibration absorber, respectively; k1 and k2 are the stiffnesses of the main vibration system and the dynamic vibration absorber, respectively; c is the damping of the dynamic vibration absorber; x1 and x2 are the displacements of the main vibration system and the dynamic vibration absorber, respectively; and F(t) is the excitation force of the main vibration system.

[0030] From equation (1), the dynamic amplification factor of the displacement of the main vibration system with respect to the excitation force is derived as follows:

[0031] (2)

[0032] In the formula: g = ω / ω n For frequency ratio, ω n The natural circular frequency of the main oscillation system; f=ω a / ω n For the tuning ratio, ω a The natural frequency of the vibration absorber; μ = m / M is the mass ratio; η a This is the damping ratio of the vibration absorber.

[0033] The optimal tuning ratio is: f = 1 / (1+μ) (3)

[0034] The optimal damping ratio is:

[0035] (4)

[0036] Substituting equations (3) and (4) into equation (2), we can obtain

[0037] (5)

[0038] As can be seen from equation (5), the larger the mass ratio, the better the vibration absorption effect of the dynamic vibration absorber. However, in the initial design stage, the selection is usually based on actual requirements. According to experimental verification, the optimal value is between 0.39 and 0.44, which can reduce the vibration acceleration to below 50%. If the mass of the dynamic vibration absorber is too large, it is not very meaningful to use the dynamic vibration absorber scheme to suppress the vibration of the main system.

[0039] The rubber elastomer 5 between the mass block 2 and the base 6 is fixed to the base 6 by calculating the optimal damping ratio and by molding and vulcanization.

[0040] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

Claims

1. A dynamic vibration absorber for small-diameter natural gas pipelines, characterized in that: It includes connecting bolts (3), connecting joints (7), rubber elastomers (5), base (6) and mass block (2). The connecting joints (7) are fixedly connected to the center of the bottom surface of the base (6). The rubber elastomers (5) are fixed to the upper surface of the base (6). The mass block (2) is located on the upper surface of the rubber elastomers (5). The mass block (2) and the rubber elastomers (5) are fixed together by connecting bolts (3).

2. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 1, characterized in that: The dynamic vibration absorber is provided in multiple sets, with two in each set. A connector (8) is fixed on the natural gas pipeline. The two dynamic vibration absorbers in each set are fixed to both ends of the connector (8) through a connector (7).

3. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 2, characterized in that: The connector (8) includes an upper component and a lower component. The middle section of the upper and lower components are semi-circular arc plates that fit with the natural gas pipeline, and the two ends are straight plates. The upper and lower components are fixed together through threaded holes opened on the straight plates.

4. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 3, characterized in that: The mass block (2) is a circular barrel structure with a hollow interior, and a rubber gasket (4) is provided between the connecting bolt (3) and the mass block (2).

5. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 4, characterized in that: A removable cover plate is provided at the upper opening of the mass block (2) of the circular barrel structure.

6. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 5, characterized in that: A metal shell (1) is provided above the base (6), and the mass block (2) and the rubber elastomer (5) are both placed inside the metal shell (1).

7. The dynamic vibration absorber for small-diameter natural gas pipelines according to claim 6, characterized in that: The mass ratio of the mass block (2) to the main vibration system is 0.39 to 0.44.

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