Pipe damping acoustic superstructure and method for regulating damping

Abstract

The present application relates to the field of pipeline vibration and noise reduction, and particularly relates to a pipeline vibration and noise reduction acoustic superstructure, which comprises a bottom plate, a plurality of strong magnets are mounted on the lower surface of the bottom plate and fixed to the outer surface of the pipeline through the strong magnets, a top cover is arranged on the upper surface of the bottom plate, a damping sheet is attached to the inner side of the top cover, a plurality of local resonance units are arranged in an array in the closed space formed by the top cover and the bottom plate, handles are arranged in the middle of the two sides of the bottom plate and detachably connected to the pipeline; the local resonance unit is an integrated structure composed of a mass block and a connecting rod, one end of the connecting rod is fixed to the annular bottom plate, the other end is connected to the mass block, and a damping strip is arranged between every two rows of local resonance units. For different noise spectra, the mass is changed by changing the size of the mass block or the size of the connecting rod, so as to adjust the resonance frequency and realize vibration reduction and regulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pipeline vibration and noise reduction, and particularly relates to a pipeline vibration and noise reduction acoustic superstructure and a regulation and control vibration reduction method. BACKGROUND

[0002] With the continuous expansion and rapid development of urban construction, the urban population has been increasing in recent years, and the efforts to control pollution and haze and protect the blue sky have been intensified. The consumption of natural gas has been growing rapidly, resulting in a substantial increase in the daily processing capacity and gas supply of some stations. The noise generated at the throttling device or pressure regulating branch of the gas pipeline is as high as 110 dB. The continuous full load, high flow rate and large flow rate of the pressure regulating branch cause the vibration of the gas pipeline and equipment in the pressure regulating branch, and the high-intensity noise and vibration exacerbate the frequent equipment failures, such as valve core fracture, valve body perforation, needle valve vibration and equipment heating, causing the interruption of winter transportation of natural gas every year, and the economic loss of equipment maintenance of a single gas station reaching the order of magnitude of millions. The high-intensity noise also has a great impact on the surrounding environment of the station, and the disputes and economic losses caused by the noise problem are becoming increasingly serious, which also affects the quality of life of the surrounding residents and violates the relevant noise regulations. For the station maintenance personnel, the noise is harmful to the hearing system, nervous system and cardiovascular system, and causes serious harm to the physical and mental health of the personnel. Therefore, the vibration and noise reduction of the natural gas pipeline is not only a key means to ensure the safety of natural gas transportation and improve economic benefits, but also an urgent need for environmental governance and a guarantee for personnel health and safety.

[0003] In order to reduce the noise of the gas pipeline branch of the station, traditional vibration and noise reduction materials such as rubber damping and porous materials are usually used for overall coating, which cannot achieve efficient vibration and noise reduction for specific frequency and frequency band, and is not conducive to personnel maintenance and station inspection. The use of traditional vibration and noise reduction materials is a challenge due to the particularity of the space quality and working environment of the natural gas branch pipeline. Although the traditional internal vibration and noise reduction measures, such as the use of porous plates and small hole jet flow, can reduce the internal flow field pulsation and thus reduce the vibration and noise, they will cause pressure loss to the internal gas flow of the natural gas pipeline, affecting the overall gas transportation efficiency. Therefore, the existing vibration and noise reduction methods cannot meet the complex environmental working requirements of the gas pipeline branch, and cannot achieve compact and efficient vibration and noise reduction. Therefore, a new vibration reduction structure is needed to suppress the vibration and noise of the pipeline. SUMMARY

[0004] Therefore, the present application provides a pipeline vibration and noise reduction acoustic superstructure, which is designed and attached to a resonant acoustic superstructure material module corresponding to the frequency band by targeting the vibration characteristics of different parts of the natural gas pipeline branch, so as to give a distributed arrangement of the pipeline vibration reduction design, and to achieve the suppression of the overall vibration of the natural gas pipeline and the reduction of the pipeline sound radiation noise.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] A pipeline damping acoustic superstructure, comprising a bottom plate, a plurality of strong magnets are mounted on the lower surface of the bottom plate, and the strong magnets are fixed to the outer surface of the pipeline, a top cover is arranged on the upper surface of the bottom plate, a damping sheet is attached to the inner side of the top cover, a plurality of local resonance units are arranged in an array in the closed space formed by the top cover and the bottom plate, a handle is arranged in the middle of the two sides of the bottom plate, and the handle is detachably connected to the pipeline;

[0007] The local resonance unit is an integrated structure composed of a mass block and a connecting rod, one end of the connecting rod is fixed to the annular bottom plate, and the other end is connected to the mass block, and a damping strip is arranged between every two rows of local resonance units.

[0008] Further, the size of the local resonance units in each row or column of the local resonance unit array is the same, the size of the mass blocks is the same, and the size of the connecting rods is the same.

[0009] Further, the strong magnets are fixed to the bottom plate by non-magnetic metal connecting screws.

[0010] Further, the bottom plate is an arc-shaped plate made of non-magnetic metal, which is attached to the pipeline, and the local resonance units are arranged in a ring shape and concentrically aligned with the center of the arc-shaped bottom plate.

[0011] Further, the bottom plate and the top cover are provided with through holes corresponding to each other, and bolts are arranged in the through holes.

[0012] Further, the damping strip and the damping sheet are made of rubber material, and one side is attached with adhesive tape for adhesion of the damping strip to the bottom plate and the damping sheet to the top cover, and the damping sheet is L-shapedly attached to the top cover.

[0013] Further, a reinforcing rib is attached to the center of the top cover.

[0014] A method for regulating damping according to the foregoing pipeline damping acoustic superstructure, characterized in that: for different noise spectra, the mass of the mass block is changed by changing the size of the mass block, so as to adjust the resonance frequency to achieve damping regulation.

[0015] A method for regulating damping according to the foregoing pipeline damping acoustic superstructure, characterized in that: for different noise spectra, the resonance frequency is adjusted by changing the size of the connecting rod to achieve damping regulation.

[0016] Further, a method for regulating damping of a pipeline damping acoustic superstructure, the expression of the first-order resonance frequency f of the local resonance unit is:

[0017]

[0018] Wherein, E is the Young's modulus of the material, unit is pascal, I is the moment of inertia of the connecting rod, I = bh 3 / 12, b and h are the width and height of the section, l is the length of the connecting rod, b, h and l are all units of meters, m is the mass of the mass block, unit is kilogram.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] Compared with traditional noise reduction materials such as rubber and porous materials, it has low, medium and high frequency designability, and by changing the size of the local resonance unit composed of the mass block and the connecting rod and arranging it on the bottom plate, it can be designed to be adjustable and controllable.

[0021] Compared with the overall pipe covering noise reduction measure of rubber and porous materials, the present application realizes distributed design, each noise reduction module is connected with the pipe using strong magnetism, and has detachability, facilitating pipe maintenance and station inspection, in addition, damping materials are attached on the top of the bottom plate and in the top cover, which can be used to increase the vibration and noise reduction effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a cross-sectional structure diagram of the noise reduction module A of the embodiment of the present application.

[0023] Figure 2 is a top view of the noise reduction module A after removing the top cover and damping sheet.

[0024] Figure 3 is a schematic diagram of the geometric parameters of the local resonance unit.

[0025] Figure 4 is a cross-sectional structure diagram of the noise reduction module B of the embodiment of the present application.

[0026] Figure 5 is a top view of the noise reduction module B after removing the top cover and damping sheet.

[0027] Figure 6 is a schematic diagram of the distributed arrangement of the noise reduction module A and the noise reduction module B in the pipe.

[0028] Figure 7 is a comparison diagram of the pipe surface vibration response before and after the distributed arrangement of the noise reduction module A and the noise reduction module B.

[0029] Figure 8 is a comparison diagram of the pipe radiation sound field response before and after the distributed arrangement of the noise reduction module A and the noise reduction module B.

[0030] In the figure: 1, mass block; 2, connecting rod; 3, top cover; 4, damping sheet; 5, strong magnet; 6, bottom plate; 7, damping strip; 8, handle; 9, noise reduction module A; 10, noise reduction module B. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application are further described below with reference to the accompanying drawings. The illustrative embodiments of the present application and their description serve the purpose of explaining the present application. They are not intended to limit the scope of the present application. It will be understood that modifications or combinations of this structure can be made for other embodiments without departing from the scope of the present application.

[0032] A pipeline damping acoustic superstructure, comprising a bottom plate 6, a plurality of strong magnets 5 are mounted on the lower surface of the bottom plate 6, and the strong magnets 5 are fixed to the outer surface of the pipeline, a top cover 3 is arranged on the upper surface of the bottom plate 6, a damping sheet 4 is attached to the inner side of the top cover 3, a plurality of local resonance units are arranged in an array in the closed space formed by the top cover 3 and the bottom plate 6, a handle 8 is arranged in the middle of the two sides of the bottom plate 6, and the handle 8 is detachably connected between the pipeline;

[0033] The local resonance unit is an integrated structure composed of a mass block 1 and a connecting rod 2, one end of the connecting rod 2 is fixed to the annular bottom plate 6, and the other end is connected to the mass block 1, and a damping strip 7 is arranged between every two rows of local resonance units.

[0034] As shown in Figure 1 , Figure 2 , the local resonance units composed of the connecting rod 2 and the mass block 1 are uniformly welded on the bottom plate 6, the damping strips 7 are arranged between the units, three grooves for the strong magnets 5 are opened below the bottom plate 6, the bottom plate 6 is provided with threaded holes for connecting the strong magnets, the side edges are provided with through holes for connecting the top cover 3, and the two end sides are welded with the handle 8. The top cover 3 is processed by sheet metal, the front and rear panels are welded, the side edges are provided with through holes for bolting with the bottom plate 6, the center is welded with a reinforcing rib to increase the structural strength, and the damping sheets 4 are attached to the two sides of the internal reinforcing rib to increase the damping and noise reduction capacity.

[0035] The annular arrangement of the local resonance units composed of the connecting rod 2 and the mass block 1 is concentrically aligned with the center of the arc of the bottom plate, so as to reduce the size error caused by the connection of the connecting rod and the bottom plate.

[0036] First, the local resonance unit composed of a single mass block 1 and a connecting rod 2 should be designed, which can be regarded as a system of mass block and spring. Since the first-order resonance frequency is often the strongest, the first-order resonance frequency of the local resonance unit composed of the mass block 1 and the connecting rod 2 is designed to be consistent with the target frequency, and the noise spectrum has multiple characteristic frequencies or frequency bands, which can be changed by adjusting the size of the mass block 1 or the length and cross-sectional size of the connecting rod 2 to change the first-order resonance frequency.

[0037] As shown in Figure 3Considering small elastic deformation, the moment of force at any point x of the cantilever beam in transverse vibration is defined as M(x) = 3EI(w1-w0)(l-x) / l 3 , where I = bh 3 / 12, l, b and h are the length, width and height of the connecting rod, respectively, in meters, E is the Young's modulus of the material, in pascal, and w1 and w0 are the longitudinal displacements of the mass and the connecting rod, respectively, in meters. The elastic potential energy U m and the kinetic energy T m of the mass-beam system are defined as: It is assumed that the displacement w0 of the connecting rod and the displacement w1 of the mass have the following form: w0 = Ae -iωt , w1 = Be -iωt , where A, B are constants, e is the natural logarithm, and ω is the circular frequency. Ignoring the phase difference between w0 and w1, when only the mass-beam system is considered, the longitudinal displacement of the rod w0 = 0, and the conservation of mechanical energy is expressed as: U m -T m = 0. By substituting w1 = Be -iωt into the expression of the conservation of mechanical energy, the following equation can be solved: And through the relationship between the circular frequency and the frequency ω = 2πf, the first-order resonance frequency of the structure can be obtained: , in Hz.

[0038] A plurality of local resonance units of different sizes are arranged on the bottom plate 6. The sizes of the local resonance units in the axial direction of the bottom plate 6 are consistent, and five identical local resonance units are uniformly arranged in the circumferential direction. The size of the connecting rod 2 remains unchanged, and the height of the mass block 1 is changed to adjust the resonance frequency. The specific structural parameters and characteristic frequencies are shown in Table 1. It can be seen that the designed frequency points are between 1000 Hz and 2000 Hz, which are referred to as noise reduction module A. In order to broaden the vibration reduction and noise reduction effect, 2000 Hz-3200 Hz local resonance type vibration absorbers are also added in this embodiment, as shown in Figure 4 , Figure 5 . Compared with the 1000 Hz-2000 Hz vibration absorber, the size is changed, but the adjustment method is consistent. The size of the connecting rod 2 remains unchanged, the height of the mass block 1 is changed to adjust the first-order resonance frequency of the local resonance unit, and the sizes of the remaining structural parts do not change. Only the number of vibrators increases from 5x5 to 6x6, and the coordinate position changes. The specific structural parameters and characteristic frequencies are shown in Table 2, which are referred to as noise reduction module B.

[0039] Table 1 Geometric parameters of local resonance units of noise reduction module A

[0040]

[0041] Table 2 Geometric parameters of local resonance units of noise reduction module B

[0042]

[0043]

[0044] The noise reduction module A and the noise reduction module B are arranged circumferentially on the pipeline with an interval of 90°, and three groups are arranged circumferentially because the pipeline is generally supported from below in actual conditions. The noise reduction module A and the noise reduction module B are further arranged in three groups in the axial direction of the pipeline, so that a total of nine noise reduction module A and nine noise reduction module B are arranged on the pipeline, and the arrangement schematic diagram is shown in Figure 6 Such a modular and distributed design, in which a single noise reduction module contains multiple local resonance units with different design frequencies, can suppress vibrations of multiple frequencies. In addition, by using the detachability of the strong magnetic adsorption pipeline, multiple different noise reduction modules can be designed for vibration reduction and noise reduction of the same pipeline, which further widens the noise reduction frequency.

[0045] Based on the above design structure, the sound and vibration response of the pipeline structure shown in Figure 6 can be calculated. As shown in Figure 7 , the total sound pressure level of the radiated sound field changes as shown in Figure 8 . As can be seen from Figure 7 , the vibration acceleration of the pipeline is significantly reduced after distributed vibration reduction, especially at high frequencies, benefiting from the loss of the vibrator and the damping material. As can be seen from Figure 8 , the sound pressure level of the radiated sound field is significantly reduced at the main peak, and the sound pressure level in the remaining frequency band outside the peak frequency is also reduced to a certain extent, and the overall noise reduction effect is good.

[0046] In the above detailed description, under the condition that no other special description is made, the orientation words such as “up, middle, down, positive, negative, inner, outer” generally refer to the up, middle, down, positive, negative, inner, outer in the drawings. The components of the embodiments in the present application can be placed in various different orientations, which do not constitute an improper limitation on the present application.

Claims

1. A pipeline vibration-damping acoustic superstructure, characterized in that: Includes a base plate (6), with several strong magnets (5) installed on the lower surface of the base plate (6), which are fixed to the outer surface of the pipe through the strong magnets (5). A top cover (3) is provided on the upper surface of the base plate (6), and a damping sheet (4) is attached to the inner side of the top cover (3). Several local resonant units are arranged in an array in the closed space formed by the top cover (3) and the base plate (6). Handles (8) are provided in the middle of both sides of the base plate (6), and the handles (8) are detachably connected to the pipe. The local resonance unit is an integral structure composed of a mass block (1) and a connecting rod (2). One end of the connecting rod (2) is fixed on the annular base plate (6), and the other end is connected to the mass block (1). A damping strip (7) is provided between every two rows of local resonance units. Several local resonant units contain multiple different resonant frequencies.

2. The pipeline vibration-damping acoustic superstructure according to claim 1, characterized in that: In the local resonant unit array, the local resonant units in each row or column are the same size, the mass blocks (1) are the same size, and the connecting rods (2) are the same size.

3. The pipeline vibration-damping acoustic superstructure according to claim 2, characterized in that: The strong magnet (5) is fixed to the base plate (6) by connecting screws made of non-magnetic metal.

4. The pipeline vibration-damping acoustic superstructure according to claim 3, characterized in that: The base plate (6) is an arc-shaped plate made of non-magnetic metal, which is attached to the pipe. The circumferential arrangement of the local resonance unit is aligned with the arc center of the base plate.

5. The pipeline vibration-damping acoustic superstructure according to claim 4, characterized in that: The bottom plate (6) and the top cover (3) are respectively provided with through holes, and bolts are installed in the through holes.

6. The pipeline vibration-damping acoustic superstructure according to claim 5, characterized in that: The damping strip (7) and damping sheet (4) are made of rubber material, with adhesive tape attached to one side for bonding the damping strip (7) to the base plate (6) and the damping sheet (4) to the top cover (3). The damping sheet (4) is attached to the top cover (3) in an L-shape.

7. The pipeline vibration-damping acoustic superstructure according to claim 6, characterized in that: The top cover (4) has a reinforcing rib attached to its center.

8. A method for controlling vibration reduction via acoustic superstructure in pipelines according to claim 1, characterized in that: For different noise spectra, the mass of the mass block (1) is changed by changing its size, thereby adjusting the resonant frequency to achieve vibration reduction control.

9. A method for controlling vibration reduction via acoustic superstructure in pipelines according to claim 1, characterized in that: For different noise spectra, the resonant frequency can be adjusted by changing the size of the connecting rod (2) to achieve vibration reduction control.

Images