Multi-stage pressure reduction and noise reduction structure and silencer

Abstract

The multistage pressure reduction and noise reduction structure comprises a shell, the shell is provided with an air inlet section, a reducing section and an air outlet section which are sequentially connected, the air inlet section, the reducing section and the air outlet section form a flow channel for fluid to pass through, and a plurality of pressure reduction and noise reduction units are arranged in the flow channel. The pressure reduction and noise reduction unit comprises a pressure reduction layer and a noise reduction layer, the pressure reduction layer is close to the air inlet section relative to the noise reduction layer, a preset gap is formed between the pressure reduction layer and the noise reduction layer, a plurality of throttling holes are formed in the pressure reduction layer and the noise reduction layer, and the number of the throttling holes in the noise reduction layer is larger than that of the throttling holes in the pressure reduction layer. According to the multi-stage pressure reduction and noise reduction structure and the silencer, the requirement for large pressure difference can be met, meanwhile, the jet flow speed of fluid at the pressure reduction position is reduced, and noise is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of gas transportation, and further relates to a multi-stage pressure reduction and noise reduction structure and a silencer. Background Art

[0002] The gas pipeline transmission and distribution system is a crucial component of the entire natural gas transportation process from production sites to end users. This system generally consists of several key links, including gate stations, high-pressure pipelines, medium-pressure pipeline networks, and users. Gas pressure fluctuates during the transportation of any section of a gas pipeline, and gas pressure regulating facilities are crucial for stabilizing and regulating the pressure of the gas pipeline network system. During the pressure regulation process of high-pressure or medium-pressure gas, strong noise is generated. Firstly, after the high-pressure or medium-pressure gas passes through the valve port of the pressure regulating valve, the gas pressure drops sharply and the gas volume expands rapidly. As it passes through the valve port and the outlet flow channel, the gas impacts the inner wall of the pressure regulating valve, causing micro-gas clusters to squeeze and collide with each other, forming strong local turbulence and vortices, which in turn cause air cluster oscillations and generate intense noise. Secondly, after the high-pressure or medium-pressure gas is pressure-regulated, the gas velocity at the outlet of the pressure regulating valve is very high. Utility Model Content

[0003] In response to the above technical problems, the purpose of the present invention is to provide a multi-stage pressure reduction and noise reduction structure, which can meet the requirements of large pressure differences while reducing the jet flow rate of the fluid at the pressure reduction point, thereby significantly reducing noise.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a multi-stage pressure reduction and noise reduction structure, including a shell, the shell having an air inlet section, a reducing section and an air outlet section connected in sequence, the air inlet section, the reducing section and the air outlet section forming a flow channel for fluid to pass through, a plurality of pressure reduction and noise reduction units are provided in the flow channel, the pressure reduction and noise reduction units include a pressure reduction layer and a noise reduction layer, the pressure reduction layer is close to the air inlet section relative to the noise reduction layer, there is a predetermined gap between the pressure reduction layer and the noise reduction layer, a plurality of throttling holes are provided on the pressure reduction layer and the noise reduction layer, and the number of throttling holes on the noise reduction layer is more than the number of throttling holes on the pressure reduction layer.

[0005] In some embodiments, the gap between the pressure reduction layer and the noise reduction layer is no more than 5 mm.

[0006] In some embodiments, the diameter of the restricted hole is ≤4 mm.

[0007] In some embodiments, the number of throttle holes on the noise reduction layer is at least 1.5 times the number of throttle holes on the pressure reduction layer.

[0008] In some embodiments, a plurality of the voltage reduction and noise reduction units are stacked side by side.

[0009] In some embodiments, a plurality of the pressure reduction and noise reduction units are distributed at intervals along the flow channel.

[0010] In some embodiments, the pressure reduction layer and the noise reduction layer are separate components.

[0011] In some embodiments, the pressure reduction and noise reduction unit is generally a plate-shaped component with a silencer cavity provided therein. Throttling holes are provided on both sides of the silencer cavity to form the pressure reduction layer and the noise reduction layer on the plate-shaped component.

[0012] In some embodiments, the inner diameter of the variable diameter section gradually increases in a direction from the air inlet section to the air outlet section.

[0013] The utility model also provides a muffler, which adopts any one of the multi-stage pressure reduction and noise reduction structures described above.

[0014] Compared with the prior art, the multi-stage pressure reduction and noise reduction structure and muffler provided by the present invention have the following beneficial effects:

[0015] After the multi-stage pressure reduction and noise reduction structure is connected to the gas pipeline, the gas will pass through the pressure reduction layer and the noise reduction layer in sequence. Due to the small number of throttling holes in the pressure reduction layer and the large flow resistance, a large pressure differential will be generated. When the gas passes through the throttling holes in the pressure reduction layer, the volume expands due to the pressure drop. At the same time, the pressure energy of the gas is converted into kinetic energy of the gas, which will cause the jet flow rate of the gas after flowing through the throttling holes in the pressure reduction layer to be too high. If there is no noise reduction layer, the excessively high jet flow rate will generate a lot of noise. With the noise reduction layer, the gas will be diverted when it encounters the noise reduction layer and then flow out from the throttling holes in the noise reduction layer. Since the number of throttling holes in the noise reduction layer exceeds that of the pressure reduction layer, the jet flow rate of the gas is greatly reduced when it flows through the throttling holes in the noise reduction layer, thereby reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The preferred embodiments will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0017] Figure 1 It is a structural diagram of a multi-stage voltage reduction and noise reduction structure in a preferred embodiment of the present utility model.

[0018] Figure 2 yes Figure 1 Schematic diagram of the structure of the medium voltage reduction and noise reduction unit.

[0019] Figure 3 The present invention is a structural diagram of the part where the pressure reducing component of a muffler is located.

[0020] The reference numerals are as follows;

[0021] Air inlet section 1; diameter reducing section 2; air outlet section 3; pressure reduction and noise reduction unit 4; pressure reduction layer 41; noise reduction layer 42; throttle hole 43. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without inventive work.

[0023] refer to Figure 1 and Figure 2 According to a preferred embodiment of the present invention, a multi-stage pressure reduction and noise reduction structure comprises a tubular housing having an air inlet section 1, a reducing section 2, and an air outlet section 3. The reducing section 2 is located between the air inlet section 1 and the air outlet section 3, and the inner diameter of the reducing section 2 gradually increases in the direction from the air inlet section 1 to the air outlet section 3. The air inlet section 1, the reducing section 2, and the air outlet section 3 form a flow channel for gas circulation. The flow channel is provided with multiple pressure reduction and noise reduction units 4, each having a throttle hole 43 for gas circulation. The multiple pressure reduction and noise reduction units 4 can be stacked side by side or arranged separately in the flow channel, which is not limited in this embodiment.

[0024] According to this embodiment's multi-stage pressure-reduction and noise-reduction structure, after the inlet section 1 and outlet section 3 are connected to the gas pipeline via flanges and other components, sound waves propagating through the reducing section 2 generate interference and reflection, reducing the sound wave energy and thus noise. Furthermore, the pressure-reduction and noise-reduction unit 4 in the flow channel can also reduce the gas flow rate, significantly reducing noise.

[0025] like Figure 2 As shown, the pressure reduction and noise reduction unit 4 includes a pressure reduction layer 41 and a noise reduction layer 42. Pressure reduction layer 41 is closer to the air intake section 1 than noise reduction layer 42, with a predetermined gap of no more than 5 mm between them. Multiple throttle holes 43 with a diameter of 4 mm or less are defined in each of the pressure reduction layer 41 and the noise reduction layer 42. The number of throttle holes 43 in the noise reduction layer 42 is at least 1.5 times the number of throttle holes 43 in the pressure reduction layer 41.

[0026] After the multi-stage pressure reduction and noise reduction structure is connected to the gas pipeline, the gas will pass through the pressure reduction layer 41 and the noise reduction layer 42 in sequence. Because the number of throttle holes 43 on the pressure reduction layer 41 is small and the flow resistance is large, a large pressure differential will be generated. When the gas passes through the throttle holes 43 on the pressure reduction layer 41, the volume expands due to the pressure drop. At the same time, the pressure energy of the gas is converted into kinetic energy of the gas, resulting in an excessively high jet velocity after the gas flows through the throttle holes 43 of the pressure reduction layer 41. Without the noise reduction layer 42, the excessively high jet velocity will generate a lot of noise. With the noise reduction layer 42, the gas will be diverted when encountering the noise reduction layer 42, and then flow out from the throttle holes 43 of the noise reduction layer 42. Because the number of throttle holes 43 in the noise reduction layer 42 far exceeds the number of throttle holes 43 in the pressure reduction layer 41, the jet velocity of the gas is greatly reduced when it flows through the throttle holes 43 of the noise reduction layer 42, thereby reducing noise.

[0027] The pressure reduction layer 41 and the noise reduction layer 42 can be designed independently of each other, that is, the pressure reduction layer 41 and the noise reduction layer 42 are separate components. It is understood that the pressure reduction layer 41 and the noise reduction layer 42 can also be an integrated structure. As an example, the pressure reduction layer 41 and the noise reduction layer 42 are an integrated structure. Specifically, the pressure reduction and noise reduction unit 4 is generally a plate-shaped component, and a silencer cavity is provided in the plate-shaped component. Both sides of the silencer cavity are penetrated by throttle holes 43. The number of throttle holes 43 on one side of the silencer cavity is at least 1.5 times the number of throttle holes 43 on the other side, thereby forming the pressure reduction layer 41 and the noise reduction layer 42 on both sides of the plate-shaped component.

[0028] Flow coefficient C V The flow coefficient is an indicator of the flow capacity of the valve. It usually needs to be measured through testing, but the test is time-consuming and costly. Therefore, it is very important to know the size of the flow coefficient before the test. The IEC60534-2-1 standard provides an estimation method for the flow coefficient of the valve trim with a single-stage multi-porous cage, that is, the flow coefficient C V =0.0489×An, where An is the sum of the areas of all throttle holes 43 in the cage (unit: mm 2 ).

[0029] For multi-stage pressure reducing components, as the number of pressure reducing components increases, the comprehensive flow coefficient will gradually decrease. If there are n pressure reducing components (first stage pressure reducing component, second stage pressure reducing component, third stage pressure reducing component...nth stage pressure reducing component), the flow coefficients of these individual pressure reducing components are C V1 、C V2 、C V3 …C Vn , when the fluid flows through these pressure reducing parts in sequence, its comprehensive flow coefficient C V It can be estimated by the following formula:

[0030]

[0031] Figure 3 The present invention shows a variable diameter muffler which does not adopt a multi-stage pressure reduction and noise reduction structure. The muffler includes four pressure reducing parts, namely the first stage pressure reducing part to the fourth stage pressure reducing part. The size of the throttle hole 43 on the pressure reducing part is The quantities are 100, 200, 300, and 400. According to the IIEC60534-2-1 standard, the flow coefficients of the 1st to 4th level pressure reducing components are:

[0032] C V1 =0.0489×100×π×3×3÷4=34.57

[0033] C V2 =0.0489×200×π×3×3÷4=69.13

[0034] C V3 =0.0489×300×π×3×3÷4=103.70

[0035] C V4 =0.0489×400×π×3×3÷4=138.26

[0036] The comprehensive flow coefficient of the variable diameter silencer is:

[0037]

[0038] Figure 1 The variable diameter silencer adopting the multi-stage pressure reduction and noise reduction structure is shown, which includes two pressure reduction and noise reduction units 4. For the convenience of distinction and description, the two pressure reduction and noise reduction units 4 are defined as the first pressure reduction and noise reduction unit 4 and the second pressure reduction and noise reduction unit 4. Among them, the number of throttle holes 43 on the pressure reduction layer 41 of the first pressure reduction and noise reduction unit 4 is 130, and the number of throttle holes 43 on the noise reduction layer 42 is 200. The number of throttle holes 43 on the pressure reduction layer 41 of the second pressure reduction and noise reduction unit is 130, and the number of throttle holes 43 on the noise reduction layer 42 is 400. The sizes of the above throttle holes 43 are all

[0039] For the first pressure reduction and noise reduction unit 4, the flow coefficient C of the pressure reduction layer 41 V11、 Noise reduction layer 42 flow coefficient C V12 And the comprehensive flow coefficient C V1 As shown below:

[0040] C V11 =0.0489×130×π×3×3÷4=44.93

[0041] C V12 =0.0489×200×π×3×3÷4=69.13

[0042]

[0043] For the second pressure reduction and noise reduction unit 4, the flow coefficient C of the pressure reduction layer 41 V21、 Noise reduction layer 42 flow coefficient C V22 And the comprehensive flow coefficient C V2 As shown below:

[0044] C V21 =0.0489×130×π×3×3÷4=44.93

[0045] C V22 =0.0489×400×π×3×3÷4=138.26

[0046]

[0047] The comprehensive flow coefficient of the variable diameter silencer is:

[0048]

[0049] As can be seen above, the combined flow coefficients of the two mufflers are nearly identical. However, for the muffler without a multi-stage pressure-reduction and noise-reduction structure, the pressure differential is largely concentrated in the first-stage pressure-reducing element because the flow coefficient is much smaller than that of the other pressure-reducing elements, resulting in higher noise levels. In contrast, for the muffler with a multi-stage pressure-reduction and noise-reduction structure, the pressure differential is not excessively concentrated because the flow capacities of the first and second pressure-reducing and noise-reducing elements 4 are similar, resulting in lower noise levels.

[0050] In summary, the multi-stage pressure-reduction and noise-reduction structure and muffler proposed in this utility model can meet the requirements of large pressure differentials while reducing the jet velocity of the fluid at the pressure-reduction point, significantly reducing noise. Furthermore, this embodiment provides an estimation formula for the comprehensive flow coefficient, which can be used to estimate the flow capacity of a single pressure-reduction unit and evaluate the overall comprehensive flow capacity. By using this estimation formula, the flow capacity of each pressure-reduction unit can be made similar during the design phase, thus avoiding the phenomenon of concentrated large pressure differentials and reducing noise.

[0051] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-stage voltage reduction and noise reduction structure, characterized in that: The invention comprises a shell, wherein the shell has an air inlet section, a reducing section and an air outlet section connected in sequence, the air inlet section, the reducing section and the air outlet section forming a flow channel for fluid to pass through, a plurality of pressure reduction and noise reduction units are provided in the flow channel, the pressure reduction and noise reduction units include a pressure reduction layer and a noise reduction layer, the pressure reduction layer is closer to the air inlet section than the noise reduction layer, a predetermined gap is provided between the pressure reduction layer and the noise reduction layer, a plurality of throttling holes are provided on the pressure reduction layer and the noise reduction layer, and the number of throttling holes on the noise reduction layer is greater than the number of throttling holes on the pressure reduction layer.

2. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The gap between the pressure reduction layer and the noise reduction layer does not exceed 5 mm.

3. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The diameter of the throttle hole is ≤4mm.

4. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The number of throttle holes on the noise reduction layer is at least 1.5 times the number of throttle holes on the pressure reduction layer.

5. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: A plurality of the voltage reduction and noise reduction units are stacked side by side.

6. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The plurality of pressure reduction and noise reduction units are distributed at intervals along the flow channel.

7. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The pressure reduction layer and the noise reduction layer are separate components.

8. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: The pressure reduction and noise reduction unit is generally a plate-shaped component with a silencer cavity provided therein. Throttling holes are provided on both sides of the silencer cavity to form the pressure reduction layer and the noise reduction layer on the plate-shaped component.

9. The multi-stage voltage reduction and noise reduction structure according to claim 1, characterized in that: In the direction from the air inlet section to the air outlet section, the inner diameter of the variable diameter section gradually increases.

10. A muffler, characterized in that: A multi-stage voltage reduction and noise reduction structure as described in any one of claims 1 to 9 is adopted.

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