Silencing and rectifying device for ultrasonic flowmeter
By combining a multi-stage chamber structure with sound-absorbing materials, the direction of airflow and sound propagation is changed, solving the problem that traditional silencers cannot effectively reduce high-frequency ultrasonic noise, and achieving efficient noise reduction and low pressure loss.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN ZHENCHENG TECH CO LTD
- Filing Date
- 2025-06-12
- Publication Date
- 2026-04-28
AI Technical Summary
Traditional silencers cannot effectively reduce high-frequency ultrasonic noise during pipeline gas transmission and also suffer from significant pressure loss.
The noise reduction and rectification device adopts a multi-chamber structure. Through the rectification element composed of the outer and inner shells, combined with sound-absorbing materials, it changes the direction of airflow and sound flow propagation, forming a propagation difference between airflow and sound flow. The multi-chamber structure and sound-absorbing materials absorb sound energy and reduce the propagation of sound flow driven by airflow.
Effective noise reduction of high-frequency ultrasonic noise was achieved, with a noise reduction of ≥70dB and a pressure loss of ≤20kPa, meeting the installation requirements of ultrasonic flow meters.
Smart Images
Figure CN224175911U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of ultrasonic flow meter technology, specifically relating to a noise reduction and rectification device for ultrasonic flow meters. Background Technology
[0002] In pipeline gas transmission, the main sources of ultrasonic noise include regulating valves, throttle valves, pressure reducing valves, and pumps. These devices may adversely affect the accurate measurement of ultrasonic flow meters. During design and installation, the flow meter should be kept as far away from the noise source as possible, or measures should be taken to eliminate noise interference. Traditional tubular or plate-type silencers, due to their excessively large cross-sectional dimensions, may experience high-frequency failures. Since the failure frequency is lower than the ultrasonic frequency, the silencer may fail to achieve its noise reduction target. Utility Model Content
[0003] To address the aforementioned technical problems, this invention provides a silencing and rectifying device for ultrasonic flow meters. This silencing and rectifying device exhibits excellent sound absorption for high-frequency ultrasonic waves and minimizes pressure loss.
[0004] To achieve the objective of this utility model, the technical solution adopted is as follows:
[0005] A noise-reducing and rectifying device for an ultrasonic flow meter includes a tube body and a rectifying element disposed within the tube body. The rectifying element includes a rectifying outer shell and a rectifying inner shell with numerous small holes. The rectifying outer shell is composed of multiple identical chambers connected together. The chambers are sequentially connected along the airflow direction, consisting of an expansion section, a horizontal section, and a contraction section. The air inlet of the expansion section of the first-stage chamber is connected to the air inlet of the tube body, and the air outlet of the contraction section of the last-stage chamber is connected to the air outlet of the tube body. The cavity wall of the expansion section diffuses outward from the air inlet, the cavity wall of the horizontal section is parallel to the central axis of the tube body, and the cavity wall of the contraction section contracts towards the center and connects to the expansion sections of adjacent chambers. Sound-absorbing material is filled between the tube body and the rectifying outer shell, as well as inside the rectifying inner shell. The rectifying inner shell is located inside the rectifying outer shell, and the outer wall of the rectifying inner shell is parallel to the inner wall of the rectifying outer shell.
[0006] The noise reduction and rectification device of this utility model leads the airflow outward circumferentially in the expansion section. The purpose is to change the co-propagation of airflow and sound flow, form a propagation difference between airflow and sound flow, reduce the propagation of sound flow driven by airflow, and absorb more sound energy that has not been redirected by the sound-absorbing material of the rectification inner shell. At the same time, there are no right-angle reversals or bends in the airflow direction to lengthen the propagation channel. There are no filtering obstacles in the channel, which reduces regenerated noise and improves the noise reduction.
[0007] A horizontal section is added between the expansion and contraction sections to reduce the angle of change in airflow direction and decrease pressure loss. Simultaneously, the airflow experiences a smoother flow as it passes through the horizontal section, reducing regenerated noise from boundary layer shedding. The airflow turns inward in the contraction section, again creating a difference in air and sound propagation. Sound energy that did not turn in the horizontal and contraction sections is further absorbed by the sound-absorbing material of the rectifier shell. The airflow then turns outward again through the expansion section. This multi-stage airflow sequentially passes through multiple chambers, and the multi-stage structure repeats the above process, ensuring sufficient absorption of sound energy. The number of chamber stages can be set according to noise reduction requirements, and the air is finally discharged from the outlet, maintaining the same inlet and outlet directions.
[0008] In the process of airflow propagation, the airflow flows in a metastable state in an unobstructed channel with small angle changes, resulting in only low pressure loss. The propagation of sound waves is decomposed into two paths at the inlet: one is straight-line propagation through the sound-absorbing material and then being absorbed; the other is propagation along with the airflow in the channel, but it will enter the surrounding sound-absorbing material at an angle as small as possible with the direction of the sound-absorbing surface and be absorbed more.
[0009] The two ends of the rectifying inner shell of this invention are not planar. This avoids the airflow direction being reflected back by a planar surface.
[0010] The cross-sectional area of the airflow channel between the inner and outer shells of the rectifier described in this invention is not less than 1.2 times the cross-sectional area of the air inlet. The pressure loss of the silencing rectifier can be comparable to that of a straight-through pipe, avoiding unnecessary pressure loss due to an excessively small cross-sectional area.
[0011] In this invention, the distance from the connection point of adjacent chambers to the central axis is less than the distance from the maximum inner diameter point of the rectifier inner shell to the central axis. This distance difference creates a certain obstruction within the channel, ensuring that the airflow will always pass through the expansion section of the next-stage chamber and will not directly enter the horizontal section of the next-stage chamber from the contraction section of the upper-stage chamber without turning, thereby preventing the high-frequency ultrasonic noise frequency from exceeding the upper limit failure frequency.
[0012] The inclination angle between the cavity walls of the expansion and contraction sections and the horizontal section of this invention is no greater than 60 degrees. If the angle is greater than 60 degrees, the obstruction effect on airflow is greater than the diversion effect on sound flow, resulting in excessive pressure loss.
[0013] The outer wall of the rectifier inner shell and the inner wall of the rectifier outer shell of this utility model are connected by a circumferentially arranged connecting rod.
[0014] This utility model's silencing and rectifying device is a cascaded disc design. During airflow propagation, the airflow flows in a metastable state within an unobstructed channel with small angle changes, resulting in only low pressure loss. The airflow channel features multi-stage bends, altering the co-directional propagation of airflow and sound flow, creating a propagation difference between air and sound flows, and reducing the airflow's influence on sound flow propagation. At each bend, the sound wave is decomposed into two paths: one is linear propagation through the sound-absorbing material and absorption, and the other is propagation within the channel with the airflow, but it enters the surrounding sound-absorbing material at a minimal angle to the sound-absorbing surface, resulting in greater absorption. The use of multi-chamber rectifying elements ensures that the sound wave is repeatedly and fully absorbed within the shortest straight-line distance. For natural gas transmission, with a pipe length ≤ 2 times the total diameter, and meeting the installation requirements for ultrasonic flowmeter silencing and rectifying devices, a two-stage cascade achieves a noise reduction of ≥ 70 dB, while maintaining a pressure loss of ≤ 20 kPa. Attached Figure Description
[0015] Figure 1 A cross-sectional view of a silencing and rectifying device for a two-stage cascaded ultrasonic flow meter.
[0016] Figure 2 A cross-sectional view of a silencing and rectifying device for a three-stage cascaded ultrasonic flow meter.
[0017] Figure 3 The diagram shows the structure and airflow pattern of a silencing and rectifying device for a two-stage cascaded ultrasonic flowmeter.
[0018] Figure 4 This is a schematic diagram of the rectifier element end face of the silencing and rectifying device for the ultrasonic flow meter of this utility model.
[0019] Figure 5 This is a three-dimensional cross-sectional view of a two-stage cascaded ultrasonic gas flow meter.
[0020] Reference numerals: 1. Tube body; 2. Rectifier outer shell; 3. Rectifier inner shell; 4. Sound-absorbing material; 5. Connecting rod; 6. Airflow channel; 11. Air inlet; 12. Air outlet; 21. Primary chamber; 22. Secondary chamber; 23. Tertiary chamber; 31. Expansion section; 32. Horizontal section; 33. Contraction section. Detailed Implementation
[0021] To more clearly and in detail illustrate the objective technical solution of this utility model, the present utility model will be further described below through relevant embodiments. The following embodiments are merely illustrative of the implementation methods of this utility model and do not limit the scope of protection of this utility model. Example 1
[0022] like Figure 1 and 3As shown in Figure 5, a noise reduction and rectification device for an ultrasonic flow meter includes a tube body 1 and a rectification element disposed within the tube body 1. The rectification element includes a rectification outer shell 2 with numerous small holes and a rectification inner shell 3. The rectification outer shell 2 is composed of two identical chambers connected together. The chambers are composed of an expansion section 31, a horizontal section 32, and a contraction section 33 connected sequentially along the airflow direction. The air inlet of the expansion section 31 of the first-stage chamber 21 is connected to the air inlet 11 of the tube body 1, and the contraction section of the second-stage chamber 22... The air outlet 33 is connected to the air outlet 12 of the tube body 1; the cavity wall of the expansion section 31 expands outward from the air inlet, the cavity wall of the horizontal section 32 is parallel to the central axis of the tube body 1, and the cavity wall of the contraction section 33 contracts towards the center and connects to the expansion section 31 of the adjacent cavity; the tube body 1 and the rectifier outer shell 2, as well as the interior of the rectifier inner shell 3, are filled with sound-absorbing material 4, the rectifier inner shell 3 is located inside the rectifier outer shell 2, and the outer wall of the rectifier inner shell 3 is parallel to the inner wall of the rectifier outer shell 2.
[0023] The noise-reducing and rectifying device is installed at the front end of the flow meter, and the airflow enters the flow meter after noise reduction. The airflow enters the expansion section 31 of the first-stage chamber 21 from the inlet 11, and turns outward for the first time, changing the same direction of airflow and sound flow, forming a propagation difference between airflow and sound flow, reducing the propagation of sound flow driven by airflow, and the sound energy that has not turned is more absorbed by the sound-absorbing material 4 of the rectifier inner shell 3. The airflow enters the horizontal section 32, reducing the angle of change of airflow direction and reducing pressure loss. At the same time, the airflow is smoothed, reducing the regenerated noise from boundary layer shedding. The airflow turns inward in the contraction section 33, again forming a propagation difference between airflow and sound flow. The sound energy that has not turned in the horizontal section 32 and the contraction section 33 is more absorbed by the sound-absorbing material 4 of the rectifier outer shell 2. The airflow enters the second-stage chamber 22, and turns outward again through the expansion section. The airflow flows through the two-stage chambers in sequence, and the two-stage structure repeats the above process, finally exiting from the outlet, keeping the inlet and outlet directions unchanged. Example 2
[0024] like Figure 2As shown, a noise reduction and rectification device for an ultrasonic flow meter includes a tube body 1 and a rectification element disposed within the tube body 1. The rectification element includes a rectification outer shell 2 with numerous small holes and a rectification inner shell 3. The rectification outer shell 2 is composed of three identical chambers connected together. The chambers are composed of an expansion section 31, a horizontal section 32, and a contraction section 33 connected sequentially along the airflow direction. The air inlet of the expansion section 31 of the first-stage chamber 21 is connected to the air inlet 11 of the tube body 1. The contraction section 33 of the third-stage chamber 23... 3. The air outlet is connected to the air outlet 12 of the tube body 1; the cavity wall of the expansion section 31 expands outward from the air inlet, the cavity wall of the horizontal section 32 is parallel to the central axis of the tube body 1, and the cavity wall of the contraction section 33 contracts towards the center and connects to the expansion section 31 of the adjacent cavity; the tube body 1 and the rectifier outer shell 2, as well as the interior of the rectifier inner shell 3, are filled with sound-absorbing material 4. The rectifier inner shell 3 is located inside the rectifier outer shell 2, and the outer wall of the rectifier inner shell 3 is parallel to the inner wall of the rectifier outer shell 2. Example 3
[0025] This embodiment is based on embodiment 1:
[0026] The cross-sectional area of the airflow channel 6 between the rectifier inner shell 3 and the rectifier outer shell 2 is 1.2 times the cross-sectional area of the air inlet 11.
[0027] The distance from the connection point of adjacent chambers to the central axis is less than the distance from the point with the largest inner diameter of the rectifier inner shell to the central axis.
[0028] The two ends of the rectifier inner shell 3 are not planar. Example 4
[0029] This embodiment is based on embodiment 1:
[0030] The cross-sectional area of the airflow channel 6 between the rectifier inner shell 3 and the rectifier outer shell 2 is 1.5 times the cross-sectional area of the air inlet 11.
[0031] The distance from the connection point of adjacent chambers to the central axis is less than the distance from the point with the largest inner diameter of the rectifier inner shell to the central axis.
[0032] The two ends of the rectifier inner shell 3 are not planar.
[0033] The inclination angle between the cavity walls of the expansion section 31 and the contraction section 33 and the horizontal section 32 is 60 degrees.
[0034] The sound-absorbing material 4 is a porous sound-absorbing material. It can be porous fiber sound-absorbing material, porous medium-to-high density sound-absorbing cotton, porous polyurethane foam, or other sound-absorbing materials.
[0035] The perforation rate of the rectifier outer shell 2 and the rectifier inner shell 3 is greater than 20%.
[0036] like Figure 3 and Figure 4 As shown, the rectifier inner shell 3 is connected to the inner wall of the rectifier outer shell 2 by a connecting rod 5 provided on its outer surface. Example 5
[0037] This embodiment is based on embodiment 2:
[0038] The cross-sectional area of the airflow channel 6 between the rectifier inner shell 3 and the rectifier outer shell 2 is 1.6 times the cross-sectional area of the air inlet 11.
[0039] The distance from the connection point of adjacent chambers to the central axis is less than the distance from the point with the largest inner diameter of the rectifier inner shell to the central axis.
[0040] The inclination angle between the cavity walls of the expansion section 31 and the contraction section 33 and the horizontal section 32 is 50 degrees.
[0041] The perforation rate of the rectifier outer shell 2 and the rectifier inner shell 3 is greater than 20%.
[0042] The two ends of the rectifier inner shell 3 are not planar.
[0043] The sound-absorbing material 4 is a porous fiber sound-absorbing material.
[0044] The embodiments described above merely illustrate specific implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.
Claims
1. A noise reduction and rectification device for an ultrasonic flow meter, characterized in that: The device includes a tube body and a rectifier element disposed within the tube body. The rectifier element comprises a rectifier outer shell and a rectifier inner shell, both perforated with small holes. The rectifier outer shell is composed of multiple interconnected chambers of identical structure. Each chamber is composed of an expansion section, a horizontal section, and a contraction section connected sequentially along the airflow direction. The air inlet of the expansion section of the first-stage chamber is connected to the air inlet of the tube body, and the air outlet of the contraction section of the last-stage chamber is connected to the air outlet of the tube body. The cavity wall of the expansion section diffuses outward from the air inlet, the cavity wall of the horizontal section is parallel to the central axis of the tube body, and the cavity wall of the contraction section contracts towards the center and connects to the expansion sections of adjacent chambers. Sound-absorbing material is filled between the tube body and the rectifier outer shell, as well as inside the rectifier inner shell. The rectifier inner shell is located inside the rectifier outer shell, and its outer wall is parallel to the inner wall of the rectifier outer shell.
2. The silencing and rectifying device for ultrasonic flowmeters according to claim 1, characterized in that: The two ends of the rectifier inner shell are not planar.
3. The silencing and rectifying device for an ultrasonic flow meter according to claim 1, characterized in that: The cross-sectional area of the airflow channel between the inner and outer shells of the rectifier is not less than 1.2 times the cross-sectional area of the air inlet.
4. The silencing and rectifying device for ultrasonic flowmeters according to claim 1, characterized in that: The distance from the connection point of adjacent chambers to the central axis is less than the distance from the point with the largest inner diameter of the rectifier inner shell to the central axis.
5. The silencing and rectifying device for an ultrasonic flow meter according to claim 1, characterized in that: The inclination angle between the cavity walls of the expansion and contraction sections and the horizontal section is no greater than 60 degrees.
6. The silencing and rectifying device for an ultrasonic flow meter according to claim 1, characterized in that: The outer wall of the rectifier inner shell is connected to the inner wall of the rectifier outer shell by a circumferentially arranged connecting rod.