Gas flow metering device

Abstract

The utility model belongs to the field of gas flow metering, and particularly relates to a gas flow metering device. The gas flow metering device comprises a cover body, a shell, a rectification part and a metering assembly, an opening is formed in the shell, the cover body covers the opening and forms an inner cavity, a flow passing opening is formed in the rectification part, the rectification part divides the inner cavity into a gas inlet cavity and a rectification cavity, the gas inlet cavity and the rectification cavity are communicated through the flow passing opening, and the metering assembly comprises a gas flow inlet. And the airflow inlet and the overflowing opening are staggered. According to the gas flow metering device, the reasonable layout of the rectification part and the staggered arrangement of the rectification part and the gas flow inlet act together to reduce the pressure loss of the gas flow in the metering process, so that the overall gas flow transmission efficiency and the metering accuracy are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas flow measurement, and in particular relates to a gas flow measurement device. Background Art

[0002] In the ultrasonic gas industry, gas meters are key devices for measuring and controlling gas flow. They must accurately measure the amount of gas flowing through them. To achieve this, gas meters are often equipped with internal rectifiers. These rectifiers stabilize the incoming airflow and reduce turbulence, thereby improving measurement accuracy. However, existing technologies for these rectifiers present the following issues, which hinder their efficiency and cost-effectiveness.

[0003] First, the existing rectification structure includes baffles or guide vanes, which may cause the gas to slow down when passing through the rectification structure, thereby causing a large pressure loss after intake.

[0004] Secondly, existing gas flow metering devices need to be assembled and fixed to the air inlet of the base meter or the air outlet of the valve using screws. This assembly method makes the entire structure complicated, not only time-consuming and labor-intensive installation, but also difficult to maintain and disassemble. Utility Model Content

[0005] The purpose of the present invention is to at least solve the problem of large gas pressure loss after the gas flow meter is fed into the gas flow meter. This purpose is achieved through the following technical solutions:

[0006] The utility model proposes a gas flow metering device, comprising:

[0007] a cover body, wherein the cover body is provided with an air inlet;

[0008] A shell, wherein the shell is provided with an opening, the cover is provided on the opening to form an inner cavity, and the inner wall of the inner cavity is provided with a support structure;

[0009] a rectifying portion, the rectifying portion being provided in the inner cavity and being mounted between the cover and the top of the support structure, the rectifying portion being provided with an overflow opening, the rectifying portion dividing the inner cavity into an air inlet cavity and a rectifying cavity, the air inlet cavity and the rectifying cavity being connected via the overflow opening, and the air inlet being connected to the air inlet cavity;

[0010] The metering component includes an air flow inlet, and the metering component is arranged in the rectification cavity. Along the axial direction perpendicular to the flow outlet, the air flow inlet and the flow outlet are staggered.

[0011] According to the gas flow metering device of the present invention, the rectifying part is located in the inner cavity and is mounted between the cover body and the top of the support structure. The rectifying part divides the inner cavity into an air inlet cavity and a rectifying cavity. The air inlet cavity helps to stabilize the airflow and reduce the turbulence generated when the airflow enters the rectifying cavity, so that the airflow entering the rectifying cavity is more uniform. By setting the flow port, the flow rate can be controlled and optimized, thereby reducing the pressure loss caused by excessive flow rate. The airflow inlet of the metering component and the flow port are staggered, which helps to reduce the airflow that directly impacts the airflow inlet, thereby reducing the dynamic pressure loss when the airflow enters the airflow inlet. The staggered layout further optimizes the dynamic characteristics of the airflow and ensures that the flow direction of the gas is more stable when flowing through the metering component. Therefore, the gas flow metering device of the present application can solve the problem of large pressure loss after gas intake mentioned in the prior art. The reasonable layout of the rectifying part and the staggered setting with the airflow inlet work together to reduce the pressure loss of the airflow during the metering process, thereby improving the overall airflow transmission efficiency and metering accuracy.

[0012] In addition, the gas flow metering device according to the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, the metering assembly includes a valve assembly and a guide flow channel, the metering assembly and the valve assembly are connected through the guide flow channel, a limiter is provided on the rectifying part, the limiter is a boss, the boss is arranged to protrude from the edge of the rectifying part, and the side of the boss facing the guide flow channel is in contact with the guide flow channel.

[0014] In some embodiments of the present invention, a limiting structure is provided at one end of the support structure facing the rectifying portion, the limiting structure is chamfered, and the limiting structure abuts against an edge of the rectifying portion.

[0015] In some embodiments of the present invention, a pressing piece is provided on a side of the rectifying portion facing the cover body, and the pressing piece abuts against the cover body.

[0016] In some embodiments of the present invention, the pressing member is block-shaped, and there are at least two pressing members, and at least two pressing members are spaced apart and arranged on the circumferential edge of the rectifying portion.

[0017] In some embodiments of the present invention, the rectifying portion is plate-shaped, and at least part of the edge of the rectifying portion is provided with a flow baffle, which extends in the thickness direction of the rectifying portion and is used to enclose the rectifying portion to form a recessed structure, the flow port is located at the bottom of the recessed structure, and the air inlet is located at the top of the recessed structure.

[0018] In some embodiments of the present invention, the air inlet and the flow opening are staggered along an axial direction perpendicular to the flow opening.

[0019] In some embodiments of the present invention, the cover body is provided with a groove along its thickness direction, and the air inlet is connected to the groove.

[0020] In some embodiments of the present invention, the cross-sectional area of ​​the support structure gradually decreases along the direction from the shell to the cover.

[0021] In some embodiments of the present invention, the metering component includes an ultrasonic module, the ultrasonic module is arranged in the rectification cavity, the ultrasonic module includes the air flow inlet, and the air flow inlet is connected to the rectification cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference numerals are used throughout the accompanying drawings to denote the same components. In the accompanying drawings:

[0023] Figure 1 The exploded structure diagram of the gas flow metering device according to the embodiment of the present utility model is schematically shown;

[0024] Figure 2 The following schematically shows a structural diagram of a gas flow metering device according to an embodiment of the present utility model;

[0025] Figure 3 Schematically shows a front view of a gas flow metering device according to an embodiment of the present utility model;

[0026] Figure 4 Schematically shows a right side view of a gas flow metering device according to an embodiment of the present utility model;

[0027] Figure 5 for Figure 4 Sectional view of the AA plane;

[0028] Figure 6 for Figure 5 Cross-sectional view of the middle BB surface;

[0029] Figure 7 Schematically shows a structural diagram of a housing according to an embodiment of the present utility model;

[0030] Figure 8 for Figure 7 A partial enlarged view of point C in the middle;

[0031] Figure 9 Schematically shows a front view of a cover according to an embodiment of the present utility model;

[0032] Figure 10 Schematically shows a bottom view of a cover according to an embodiment of the present utility model;

[0033] Figure 11 The figure schematically shows the structure of the rectifying part according to the embodiment of the present utility model.

[0034] The reference numerals are as follows:

[0035] 100. Gas flow metering device;

[0036] 10. Cover; 101. Air inlet cavity; 11. Air inlet; 12. Air outlet; 13. Groove; 14. Limiting groove; 15. First screw hole;

[0037] 20. Rectification unit; 201. Flow outlet; 21. Position limiting member; 22. Pressing member; 23. Flow blocking member;

[0038] 30. Housing; 301. Opening; 302. Rectification cavity; 31. Support structure; 311. Limiting structure; 32. Limiting protrusion; 33. Second screw hole;

[0039] 40. Ultrasonic module; 41. Air flow inlet;

[0040] 50. Valve assembly; 51. Valve; 52. Valve motor; 53. Guide channel. DETAILED DESCRIPTION

[0041] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0042] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0043] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0044] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped over, an element described as "below" or "beneath" another element or feature would then be oriented "above" or "above" the other element or feature. Thus, the example term "below" can encompass both above and below orientations.

[0045] like Figures 1 to 6As shown, according to the embodiment of the present invention, a gas flow metering device 100 is proposed, which includes a cover 10, a shell 30, a rectifier 20 and a metering assembly. The cover 10 is provided with an air inlet 11 and an air outlet 12, and the shell 30 is provided with an opening 301. The cover 10 is covered on the opening 301. The cover 10 and the shell 30 are combined to form an inner cavity. The inner wall of the inner cavity is provided with a support structure 31. The rectifier 20 is provided in the inner cavity. The rectifier 20 is mounted on the cover. 10 and the supporting structure 31, an overflow port 201 is provided on the rectifying portion 20, and the rectifying portion 20 divides the inner cavity into an air inlet cavity 101 and a rectifying cavity 302. The air inlet cavity 101 and the rectifying cavity 302 are connected through the overflow port 201, the air inlet 11 is connected to the air inlet cavity 101, and the air outlet 12 is connected to the metering component. The metering component is arranged in the rectifying cavity 302, and the metering component includes an air flow inlet 41. The air flow inlet 41 and the overflow port 201 are staggered along the axial direction perpendicular to the flow port 201.

[0046] According to the gas flow metering device 100 of the present invention, the rectifying part 20 is located in the inner cavity and is mounted between the cover body 10 and the top of the support structure 31. The rectifying part 20 divides the inner cavity into an air inlet chamber 101 and a rectifying chamber 302. The air inlet chamber 101 helps to stabilize the airflow and reduce the turbulence generated when the airflow enters the rectifying chamber 302, so that the airflow entering the rectifying chamber 302 is more uniform. By setting the flow port 201, the gas flow rate can be controlled and optimized, thereby reducing the pressure loss caused by too fast or too slow flow rate. The airflow inlet 41 of the metering component is staggered with the flow port 201, which helps to reduce the airflow that directly impacts the airflow inlet 41, thereby reducing the dynamic pressure loss when the airflow enters the airflow inlet 41. The staggered layout further optimizes the dynamic characteristics of the airflow, ensuring that the gas flows more smoothly when flowing through the metering component. In addition, the rectifier 20 effectively provides additional support points by setting a support structure 31 in the inner cavity formed between the cover body 10 and the shell 30. The structure is simple, which reduces the sinking or tilting of the rectifier 20 due to uneven load or improper installation, further enhances the stability of the gas flow metering device 100, and simplifies the installation process, making the installation and maintenance work more convenient and efficient. In summary, the gas flow metering device 100 of the present application can solve the problem of large pressure loss after gas intake mentioned in the prior art. The reasonable layout of the rectifier 20 and the staggered setting with the airflow inlet 41 work together to reduce the pressure loss of the airflow during the metering process, and by setting the support structure 31, an additional support point is effectively provided. The structure is simple, which reduces the sinking or tilting of the rectifier 20 due to uneven load or improper installation, and further enhances the stability of the gas flow metering device 100.

[0047] It will be appreciated that the air inlet 11 and the flow opening 201 are also staggered in a direction perpendicular to the axis of the flow opening 201. This staggered arrangement allows the airflow more space in the air inlet cavity 101 to adjust its speed and direction before entering the flow opening 201. This helps to more evenly distribute the airflow, ensuring that the airflow enters the next flow section at a more appropriate speed and direction. This uniform distribution is crucial for ensuring the accuracy and repeatability of the flowmeter.

[0048] like Figure 11 As shown, in some embodiments, the rectifying portion 20 is plate-shaped, and baffles 23 are provided around the edges of the rectifying portion 20. The baffles 23 are used to change the flow direction of the gas entering the rectifying cavity 302 from the air inlet cavity 101. The baffles 23 are baffles, which are arranged along the circumferential edge of the rectifying portion 20. The baffles extend upward along the thickness direction of the rectifying portion 20 and form a recessed structure with the rectifying portion 20. The flow opening 201 is located at the bottom of the recessed structure, and the air inlet 11 is located at the top of the recessed structure. This design allows the baffles to be effectively distributed around the rectifying portion 20 to evenly change the flow direction of the gas entering the rectifying cavity 302, ensuring uniformity and stability of the gas flow as it passes through the flow opening 201. By evenly disposing the baffles along the circumference, the flow path of the gas within the rectifying portion 20 can be effectively controlled, reducing the possibility of the gas directly impacting the rectifying portion 20, thereby reducing turbulence and pressure loss generated during gas flow.

[0049] like Figure 9 and Figure 10 As shown, in some embodiments, the cover 10 has a groove 13 formed along its thickness, and the air inlet 11 is connected to the groove 13. The cooperation between the groove 13 and the rectifying portion 20 improves the compactness and overall stability of the entire gas flow metering device 100, while optimizing the utilization efficiency of the internal space and ensuring smooth gas flow. The introduction of the groove 13 helps to reduce the volume of the overall structure, making the gas flow metering device 100 more suitable for installation requirements in compact spaces.

[0050] In some embodiments, the airflow inlet 41 is trumpet-shaped. The trumpet-shaped design of the airflow inlet 41 helps to more smoothly guide the airflow into the metering assembly. The trumpet-shaped shape increases the area receiving the airflow, thereby reducing the intake velocity without adding additional resistance, effectively reducing turbulence during gas inflow. The inner wall of the trumpet-shaped airflow inlet 41 should be designed to be smooth to minimize friction and vortex generation during airflow.

[0051] In some embodiments, the metering assembly includes a valve assembly 50, which includes a guide channel 53. A stopper 21 is provided on the rectifying portion 20. The stopper 21 is a boss that protrudes from the edge of the rectifying portion 20, and abuts against the guide channel 53 on the side of the boss facing the guide channel 53. The direct contact between the boss and the guide channel 53 provides a simple and effective positioning and restraining method, ensuring that the rectifying portion 20 is precisely aligned during assembly and remains stable during use, preventing it from sinking or tilting.

[0052] It is understood that the valve assembly 50 is detachably connected to the inner wall of the housing 30. The valve assembly 50 includes an L-shaped guide channel 53, a valve 51, a valve motor 52, a mounting platform, and connecting ribs. One end of the guide channel 53 is connected to the airflow outlet of the ultrasonic module 40. The guide channel 53 is in communication with the mounting platform. The interior of the mounting platform is used to mount the valve motor 52 and the valve 51. The guide channel 53 is connected to the inner wall of the housing 30 via connecting ribs. For example, the connecting ribs can be connected to the inner wall of the housing 30 by screwing.

[0053] In other embodiments, the limiter 21 may be a buckle, and a protrusion is provided on the guide channel 53 at a position that cooperates with the buckle. By utilizing the interaction between the buckle mechanism and the protrusion on the guide channel 53, the rectifier 20 is quickly and reliably positioned and fixed, aiming to improve the assembly efficiency and use stability of the gas flow metering device 100. The main advantage of the buckle design is that it provides an assembly method that can be completed quickly without tools, and it is also convenient when disassembling. When the buckle is pressed into place, it will form a tight fit with the protrusion on the guide channel 53, thereby ensuring that the rectifier 20 will not be displaced or fall off due to vibration or airflow pressure during operation. This physical locking mechanism also helps to maintain the sealing inside the gas flow metering device 100 and prevent gas leakage, thereby maintaining the accuracy of the measurement and the safety of the system.

[0054] like Figure 7 and Figure 8As shown, in some embodiments, a limiting structure 311 is provided at one end of the support structure 31 facing the rectifying portion 20, and the limiting structure 311 abuts against the edge of the rectifying portion 20. The support structure 31 is a reinforcing rib arranged along the axial direction of the shell 30. The top of the support structure 31 is provided with a limiting structure 311. The limiting structure 311 is chamfered, and the material of the limiting structure 311 can be an elastic material, specifically rubber. First, the limiting structure 311 adopts a chamfered design, which can reduce resistance during installation and make it easier to position and abut the rectifying portion 20. The chamfered edge also helps to reduce damage caused by installation errors, especially when the rectifying portion 20 or the support structure 31 is made of a softer material. The limiting structure 311 is made of an elastic material, which allows a certain amount of elastic deformation space during the installation process, thereby absorbing the impact or pressure during the installation process and reducing damage to the rectifying portion 20. The choice of elastic material also helps maintain good contact and positioning performance during temperature fluctuations or long-term use, as elastic materials generally have good temperature resistance and resilience. The support structure 31 is a reinforcing rib that not only provides support for the rectifier 20 but also serves as a reinforcing rib arranged along the axis of the shell 30. This not only increases the rigidity and stability of the entire shell 30 structure but also ensures the stability and deformation resistance of the rectifier 20 when subjected to gas flow pressure. The design of the reinforcing rib also helps evenly distribute the loading force, reduce local stress concentration, and extend the service life of the gas flow metering device.

[0055] like Figure 6 and Figure 11 As shown, in some embodiments, a pressing piece 22 is provided on the side of the rectifier 20 facing the cover body 10, and the pressing piece 22 abuts against the cover body 10. The pressing piece 22 abuts against the cover body 10 in order to enhance the fixation between the rectifier 20 and the cover body 10, and to ensure that the rectifier 20 can be stably maintained in a predetermined position during long-term use or when experiencing vibrations and pressure changes caused by the flow of gas. The introduction of the pressing piece 22 not only improves the reliability and stability of the entire gas flow metering device, but also simplifies the assembly process, because the pressing piece 22 can achieve quick and accurate positioning and fixation. In addition, the direct contact design of the pressing piece 22 and the cover body 10 also helps to optimize the sealing performance inside the gas flow metering device, prevent gas leakage, and thus ensure the accuracy of the measurement and the safety of the system.

[0056] Specifically, the pressing member 22 is block-shaped, one end of the block-shaped pressing member 22 is disposed on the rectifying portion 20 , and the other end faces the cover 10 and is used to abut against the cover 10 .

[0057] Specifically, the rectifying portion 20 is designed as a plate-like structure and is equipped with at least three pressing members 22, which are respectively arranged on the three edges of the plate-like rectifying portion 20. Specifically, these pressing members 22 abut against the periphery of the groove 13 on the cover body 10, and fix and position the rectifying portion 20 through physical contact, while enhancing the stability and sealing of the overall structure. The choice of setting the pressing members 22 on the three edges of the rectifying portion 20 is based on the consideration of providing uniform force distribution and ensuring the stability of the rectifying portion 20 in the groove 13. This layout can effectively avoid any skew or displacement of the rectifying portion 20 during operation and maintain the constant shape of the gas flow channel.

[0058] like Figure 5 As shown, in some embodiments, the cross-sectional area of ​​the support structure 31 gradually decreases along the direction from the housing 30 to the cover 10. By gradually reducing the cross-sectional area of ​​the support structure 31 along the direction of gas flow, the gas can be better guided to flow smoothly below the rectifying portion 20. It can be understood that by gradually reducing the cross-sectional area of ​​the support structure 31 along the direction toward the rectifying portion 20, the rectifying cavity 302 is formed into a funnel-like shape, which helps reduce the turbulence of the airflow before entering the airflow inlet 41 of the ultrasound module 40, thereby reducing the energy consumption of the entire system.

[0059] Specifically, such as Figure 7 and Figure 10 As shown, the cover 10 is provided with a plurality of first screw holes 15 , and the shell 30 is provided with a plurality of second screw holes 33 corresponding to the first screw holes 15 , respectively. Bolts enter the first screw holes 15 and the second screw holes 33 to screw the cover 10 and the shell 30 together.

[0060] Specifically, such as Figure 7 and Figure 10 As shown, a limiting protrusion 32 is provided on the shell 30 along its axial direction, and a limiting groove 14 is provided on the cover body 10. The limiting protrusion 32 is accommodated in the limiting groove 14, which further improves the positioning accuracy when the cover body 10 and the shell 30 are assembled, ensuring that the two can be accurately aligned during the assembly process, thereby enhancing the stability and sealing of the entire device.

[0061] In some embodiments, the gas flow metering device 100 further includes an ultrasonic module 40, which is disposed within the rectifying cavity 302 and communicates with the guide channel 53. Specifically, the ultrasonic module 40 includes an airflow inlet 41 and an airflow outlet, wherein the airflow inlet 41 communicates with the rectifying cavity 302, and the airflow outlet communicates with the guide channel 53.

[0062] Specifically, the ultrasonic module 40 includes at least one pair of ultrasonic transmitters and receivers. By measuring the time difference between ultrasonic waves traveling through the gas flow path, the gas flow velocity and the corresponding flow rate are calculated. The ultrasonic module 40 should have high precision and high stability to adapt to various environmental conditions.

[0063] Specifically, the valve assembly 50 includes a valve 51 and a valve motor 52. The valve motor 52 is connected to the valve 51 in a transmission manner. By precisely controlling the opening of the valve 51, the valve motor 52 can adjust the flow rate of the gas, thereby ensuring that the measurement is performed within a predetermined flow range, thereby improving the accuracy and repeatability of the measurement.

[0064] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A gas flow metering device, characterized in that: include: A cover body, wherein an air inlet is formed on the cover body; A shell body, wherein the shell body is provided with an opening, the cover body is provided on the opening to form an inner cavity, and the inner wall of the inner cavity is provided with a supporting structure; A rectifying part, the rectifying part is arranged in the inner cavity, the rectifying part is erected between the cover body and the top of the supporting structure, the rectifying part is provided with a flow opening, the rectifying part divides the inner cavity into an air inlet cavity and a rectifying cavity, the air inlet cavity and the rectifying cavity are connected through the flow opening, and the air inlet is connected to the air inlet cavity; A metering component, wherein the metering component comprises an air flow inlet, and the metering component is arranged in the rectifying cavity, and along an axial direction perpendicular to the flow opening, the air flow inlet and the flow opening are staggered.

2. The gas flow metering device according to claim 1, characterized in that: The metering component includes a valve component and a guide flow channel, the metering component and the valve component are connected through the guide flow channel, a limiter is provided on the rectifying part, the limiter is a boss, the boss is protruding from the edge of the rectifying part, and the side of the boss facing the guide flow channel is in contact with the guide flow channel.

3. The gas flow metering device according to claim 1, characterized in that: A limiting structure is provided at one end of the supporting structure facing the rectifying portion. The limiting structure is chamfered and abuts against an edge of the rectifying portion.

4. The gas flow metering device according to claim 1, characterized in that: A pressing piece is provided on a side of the rectifying portion facing the cover body, and the pressing piece abuts against the cover body.

5. The gas flow metering device according to claim 4, characterized in that: The pressing piece is block-shaped, and the number of the pressing pieces is at least two, and at least two of the pressing pieces are arranged at intervals on the circumferential edge of the rectifying portion.

6. The gas flow metering device according to any one of claims 1 to 5, characterized in that: The rectifying portion is in the shape of a plate, and a flow baffle is provided on at least part of the edge of the rectifying portion. The flow baffle extends in the thickness direction of the rectifying portion and is used to enclose the rectifying portion to form a recessed structure. The flow port is located at the bottom of the recessed structure, and the air inlet is located at the top of the recessed structure.

7. The gas flow metering device according to any one of claims 1 to 5, characterized in that: Along an axial direction perpendicular to the flow opening, the air inlet and the flow opening are staggered.

8. The gas flow metering device according to any one of claims 1 to 5, characterized in that: The cover body is provided with a groove along the thickness direction thereof, and the air inlet is communicated with the groove.

9. The gas flow metering device according to any one of claims 1 to 5, characterized in that: Along the direction from the shell to the cover, the cross-sectional area of ​​the support structure gradually decreases.

10. The gas flow metering device according to any one of claims 1 to 5, characterized in that: The metering component includes an ultrasonic module, which is arranged in the rectification cavity. The ultrasonic module includes the airflow inlet, which is communicated with the rectification cavity.

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