Air volume meter

Abstract

The utility model discloses an air volume meter which comprises a collecting module, a pressure measuring module and a control module, a base body of the collecting module forms two independent spaces through a partition plate, the collecting module is provided with a plurality of air inlets, a pressure taking opening and an air inlet pipe with air holes in the windward direction and the leeward direction, multi-point pressure taking is achieved, and the pressure measuring module comprises a pressure taking pipe and a pressure difference sensor. The control module can measure pressure in different ranges, calculates air volume data according to pressure difference information output by the pressure difference sensor, and automatically switches the measuring ranges. Compared with the prior art, through wide-range multi-site pressure taking and component range measurement, the large-tuyere air volume measurement precision is improved, and the large-tuyere air volume measurement device can adapt to complex tuyere environments and can be widely applied to the fields needing air volume measurement such as mine ventilation, petrochemical engineering and environment detection.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of air volume measuring equipment, especially relates to a kind of air volume meter for the air duct air volume measurement of air port in heating, air conditioning, purification technology and other industries. BACKGROUND

[0002] Air volume meter is widely used in many important fields and plays a key role, but the existing technology has certain limitations. Air volume meter is indispensable in mine ventilation, petroleum chemical industry, metallurgy, environmental detection and many other fields. In mine ventilation, accurate measurement of air volume can ensure air circulation underground, provide a safe working environment for miners and effectively prevent safety hazards such as gas accumulation. In the field of petroleum chemical industry, accurate measurement of air volume is crucial for process control and optimization, and is related to product quality and production efficiency. In the metallurgical industry, air volume measurement is used for combustion control of furnaces and other equipment, affecting energy utilization efficiency and product quality. In environmental detection, air volume measurement is an important source of data for assessing air quality and monitoring pollution source diffusion. At the same time, in the heating, air conditioning and purification technology industries, air volume meter is used to measure the air duct air volume of air port to ensure that the indoor environment is comfortable and the air quality meets the standard, meeting the needs of people's life and work.

[0003] Currently common air volume meters include pitot tube type air speed and air volume meter and thermal type air speed and air volume meter. The pitot tube type air volume meter has obvious shortcomings, with a single pressure point. When measuring the air speed and air volume of a large air port, the air speed at different positions of the large air port differs, and a single pressure point cannot accurately reflect the air speed and air volume of the entire air port, resulting in the need for improved measurement accuracy. In addition, existing air volume meters are usually single-range products designed for specific measurement environments, making it difficult to cope with complex and variable air port environments.

[0004] Therefore, how to solve the above-mentioned shortcomings of the prior art has become the subject of research and solution of the utility model. INVENTION CONTENTS

[0005] Therefore, the utility model aims to provide an air volume meter.

[0006] To achieve the above-mentioned purpose, the utility model adopts the technical scheme of:

[0007] An air volume meter comprises:

[0008] The collecting module comprises a base body with a cavity, the cavity is divided into a first space and a second space which are not communicated with each other by a partition plate, a first pressure taking port is arranged on the upper wall of the base body with the first space, a second pressure taking port is arranged on the lower wall of the base body with the second space, a plurality of first air inlets and a plurality of second air inlets are arranged on the cavity wall of the base body, the first space obtains airflow flowing from the air inlet direction through the first air inlets; the second space obtains airflow flowing away from the air inlet direction through the second air inlets; each first air inlet is communicated with the first pressure taking port through the first space, and each second air inlet is communicated with the second pressure taking port through the second space;

[0009] The pressure measuring module comprises a first pressure taking pipe, a second pressure taking pipe and a first differential pressure sensor, the first pressure taking pipe is connected with the first pressure taking port and the first differential pressure sensor, and the second pressure taking pipe is connected with the second pressure taking port and the first differential pressure sensor.

[0010] The control module is electrically connected with the first differential pressure sensor and is configured to calculate air volume data according to a differential pressure signal output by the first differential pressure sensor.

[0011] Preferably, the collecting module further comprises a plurality of first air inlets and a plurality of second air inlets, each first air inlet is communicated with each first air inlet one by one, each second air inlet is communicated with each second air inlet one by one, one end of each first air inlet away from the first air inlet is not communicated with the outside, and one end of each second air inlet away from the second air inlet is not communicated with the outside.

[0012] Preferably, a plurality of first air holes are arranged on the side of the first air inlet facing the air inlet direction, and a plurality of second air holes are arranged on the side of the second air inlet away from the air inlet direction.

[0013] Preferably, the pressure measuring module comprises a third pressure taking pipe, a fourth pressure taking pipe and a second differential pressure sensor, one end of the third pressure taking pipe is connected with the first pressure taking port, and the other end of the third pressure taking pipe is connected with the second differential pressure sensor.

[0014] One end of the fourth pressure taking pipe is connected with the second pressure taking port, and the other end of the fourth pressure taking pipe is connected with the second differential pressure sensor.

[0015] Preferably, the second differential pressure sensor is electrically connected with the control module.

[0016] Preferably, the first three-way valve has an inlet connected with the first pressure tapping port, and two outlets connected with the first pressure tapping pipe and the third pressure tapping pipe respectively; and the second three-way valve has an inlet connected with the second pressure tapping port, and two outlets connected with the second pressure tapping pipe and the fourth pressure tapping pipe respectively.

[0017] The first three-way valve and the second three-way valve are both connected with the control module, the control module controls the first pressure tapping port to be connected with or disconnected from the first pressure tapping pipe and the third pressure tapping pipe through the first three-way valve, and the control module controls the second pressure tapping port to be connected with or disconnected from the second pressure tapping pipe and the fourth pressure tapping pipe through the second three-way valve.

[0018] Preferably, the first inlet pipe and the second inlet pipe are both distributed symmetrically along the circumference of the base body.

[0019] Preferably, the first pressure tapping port and the second pressure tapping port are oppositely arranged.

[0020] Compared with the prior art, the beneficial effects of the utility model lie in that: multiple first inlet pipes and second inlet pipes and multiple air holes opened on the first inlet pipes and the second inlet pipes are arranged to realize multi-point air inlet, to obtain air from two directions of air inlet and air outlet at multiple angles and multiple positions, and then to uniformly mix the air sampled from the two directions of air inlet and air outlet in the first space and the second space respectively, so that the pressure of the air volume meter used for calculating the air flow of the air inlet direction is more accurate, compared with the single pressure tapping point pitot tube type air volume meter in the prior art, the air volume meter can more comprehensively reflect the air speed conditions at different positions of the air inlet, effectively improves the measurement accuracy, and is particularly suitable for air speed and air volume measurement of large air inlets. By selecting different pressure tapping pipes and differential pressure sensors through the control module, the air volume meter can cope with complex air inlet environments with large air volume range changes, can accurately measure in low air volume or high air volume scenes, overcomes the limitations of the single range air volume meter in the prior art, and expands the application range of the air volume meter. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0022] ATTACHMENT Fig. 1 It is the overall structure schematic diagram of the air volume meter of the present application.

[0023] ATTACHMENT Fig. 2Structure diagram of the collection module of the present application;

[0024] Figure Fig. 3 Principle diagram of the pressure measurement module of the present application.

[0025] Explanation of the reference signs and components involved in the drawings:

[0026] 1, collection module; 11, base body; 111, partition; 112, first space; 113, second space; 114, first pressure tapping port; 115, second pressure tapping port; 116, first air inlet; 117, second air inlet; 12, first air inlet pipe; 121, first air hole; 13, second air inlet pipe; 131, second air hole; 2, pressure measurement module; 21, first pressure tapping pipe; 22, second pressure tapping pipe; 23, first differential pressure sensor; 24, third pressure tapping pipe; 25, fourth pressure tapping pipe; 26, second differential pressure sensor; 27, first three-way valve; 28, second three-way valve; 3, control module. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely in the following detailed description. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] Referring to Figure Figs. 1-3 The air volume meter of the present application includes a collection module 1, a pressure measurement module 2, and a control module 3. The collection module 1, i.e. the collection core, includes a base body 11 as its core component. The base body 11 is generally made of high-strength, corrosion-resistant metal or alloy material. Such material not only ensures the structural stability of the base body 11 in complex environments, but also effectively resists chemical erosion, prolonging the service life of the air volume meter.

[0029] The base body 11 is internally provided with a cavity, and the cavity is provided with a partition 111. The partition 111 divides the cavity into a first space 112 and a second space 113 that are not in communication with each other in the base body 11. Fig. 1When the air inlet direction is defined as from top to bottom, the structure of the collection module is as follows relative to the air inlet direction: the first space 112 is located above the second space 113, and the design of the partition plate 111 needs to ensure good sealing to prevent air flow between the two spaces from interfering with each other. The partition plate 111 can be made of the same material as the base body 11 and can be tightly connected to the base body 11 by means of integrated molding, welding or sealant. The upper wall of the base body 11 with the first space 112 is provided with a first pressure tapping port 114, and the lower wall of the base body 11 with the second space 113 is provided with a second pressure tapping port 115. Preferably, the first pressure tapping port 114 and the second pressure tapping port 115 are oppositely arranged, which helps to more accurately measure the pressure difference between the air inlet direction and the direction away from the air inlet direction. The diameter and shape of the pressure tapping port need to be optimized according to the actual measurement requirements and air flow characteristics. Generally, the diameter of the pressure tapping port should not be too large or too small to ensure that the pressure signal can be effectively collected.

[0030] A plurality of first air inlets 116 and a plurality of second air inlets 117 are provided on the cavity wall of the base body 11. The first space 112 obtains air flow from the air inlet direction through the first air inlets 116, and the second space 113 obtains air flow from the direction away from the air inlet direction through the second air inlets 117, so that air from the air inlet direction and air from the direction away from the air inlet direction can enter different spaces and ultimately be transmitted to the corresponding pressure tapping port, thereby realizing the measurement of the pressure difference between the first pressure tapping port 114 and the second pressure tapping port 115 of the collection module. The first air inlets 116 are located on the cavity wall of the base body 11 with the first space 112, and the second air inlets 117 are located on the cavity wall of the base body 11 with the second space 113. Each first air inlet 116 is in communication with the first pressure tapping port 114 through the first space, and each second air inlet 117 is in communication with the second pressure tapping port 115 through the second space 113, so that air can enter the first space 112 or the second space 113 from different positions, providing a basis for multi-point pressure measurement.

[0031] The pressure measurement module 2 includes a first pressure tapping pipe 21, a second pressure tapping pipe 22 and a first pressure difference sensor 23. One end of the first pressure tapping pipe 21 is connected to the first pressure tapping port 114, and the other end is connected to the first pressure difference sensor 23. One end of the second pressure tapping pipe 22 is connected to the second pressure tapping port 115, and the other end is connected to the first pressure difference sensor 23. The first pressure difference sensor 23 is connected to the control module 3, and the control module 3 calculates the air volume data according to the pressure difference information output by the first pressure difference sensor 23 and according to the formula stored in the internal memory.

[0032] The collecting module further comprises a plurality of first air inlet pipes 12 and a plurality of second air inlet pipes 13. Each first air inlet pipe 12 is in one-to-one correspondence with each first air inlet 116, and each second air inlet pipe 13 is in one-to-one correspondence with each second air inlet 117. The material and pipe diameter of the first air inlet pipe 12 and the second air inlet pipe 13 need to be selected according to the expected air flow to be monitored. Generally, the same material as the base body 11 is used, and the pipe diameter should be moderate to ensure smooth airflow. The end of each first air inlet pipe 12 away from the first air inlet 116 is not connected to the outside, and the end of each second air inlet pipe 13 away from the second air inlet 117 is not connected to the outside, which can avoid the overflow of the air flow obtained by the first air inlet pipe 12 and the second air inlet pipe 13 and the interference of external air flow, and ensure that the air flow in the first air inlet pipe 116 comes from the air inlet direction, and the air flow in the second air inlet pipe 117 comes from the direction away from the air inlet direction.

[0033] The first air inlet pipe 12 and the second air inlet pipe 13 are symmetrically arranged along the circumference of the base body 11. For example, a plurality of first air inlet pipes 12 are arranged in a uniform array around the base body, and a plurality of second air inlet pipes 13 are arranged in a uniform array around the base body. In addition, one first air inlet pipe 12 and one second air inlet pipe 13 can also be symmetrically distributed in the horizontal direction as shown. Fig. 1

[0034] The first air inlet pipe 12 is provided with a plurality of first air holes 121 on the side facing the air inlet direction, and the second air inlet pipe 13 is provided with a plurality of second air holes 131 on the side away from the air inlet direction. The number of first air holes 121 and second air holes 131 is not specifically limited, for example, 3-5 first air holes 121 are arranged on one first air inlet pipe 12, and 3-5 second air holes 131 are arranged on one second air inlet pipe 13. The size, number and distribution of the first air holes 121 and the second air holes 131 need to be optimized according to the actual measurement requirements. The size of the air hole should be moderate to ensure that the air flow pressure can be effectively collected, while avoiding too large air holes causing too much air flow into the corresponding first air inlet pipe 12 or second air inlet pipe 13. The number and distribution of the air holes should be uniform to ensure that the air flow at different positions can be fully collected. For example, the first air hole 121 and the second air hole 131 have an opening less than 6mm, such as 0.3mm, 1mm, 2mm, 3mm, 4mm, 5mm, etc., and the inlet cross-sectional area of the first air inlet 116 and the second air inlet 117 is 1-30cm 2 , for example, 3cm 2 , 6cm 2 , 10cm 2 , 15cm 2 , 20cm 2 , 25cm 2 ​Of course, no specific limitation is made to the opening size and number of the first air holes 121 and the second air holes 131, and no specific limitation is made to the inlet opening cross-sectional area of the first air inlet 116 and the second air inlet 117, which can be larger or smaller on the basis of the above, and the specific size is determined according to the size of the air volume meter, the size of the air outlet to be measured, and other factors.

[0035] It can be understood that, as a first implementable manner, each first air inlet 116 and each second air inlet 117 can be formed in the side wall of the base body 11, at this time, the first air inlet pipe 12 and the second air inlet pipe 13 can be straight pipes, and each first air inlet pipe 12 and each second air inlet pipe 13 are placed horizontally and connected in communication with the corresponding each first air inlet 116 and each second air inlet 117; as a second implementable manner, each first air inlet 116 can be formed in the upper wall of the base body 11 and surround the first pressure tapping 114, and each second air inlet 117 can be formed in the lower wall of the base body 11 and surround the second pressure tapping 115, at this time, the airflow in the air inlet direction can be obtained through each first air inlet 116, and the airflow away from the air inlet direction can be obtained through each second air inlet 117, but this will make the airflow sampling position range smaller, therefore, each first air inlet 116 can still be connected to the first air inlet pipe 12, and each second air inlet 117 can still be connected to the second air inlet pipe 13, at this time, at least part of the pipe segments of the first air inlet pipe 12 and the second air inlet pipe 13 are pipe segments perpendicular to the air inlet direction, and the first air holes 121 and the second air holes 131 are also formed on the pipe segments perpendicular to the air inlet direction, for example, the first air inlet pipe 12 and the second air inlet pipe 13 are L-shaped, which is not specifically limited here.

[0036] In addition, the first air inlet pipe 12 and the second air inlet pipe 13 can be independent of each other; or one first air inlet pipe 12 and one second air inlet pipe 13 can be taken as a group, and after one or more air inlet pipe partition plates are arranged in one air inlet pipe, one first air inlet pipe 12 and one second air inlet pipe 13 are obtained by partitioning the pipe, and the first air inlet pipe 12 and the second air inlet pipe 13 obtained after partitioning are connected in communication with the corresponding first air inlet 116 and second air inlet 117, and the first air inlet pipe 12 and the second air inlet pipe 13 obtained after partitioning are not connected to each other.

[0037] In addition, the pressure measuring module 2 can further include a third pressure tapping pipe 24, a fourth pressure tapping pipe 25 and a second differential pressure sensor 26. One end of the third pressure tapping pipe 24 is connected with the first pressure tapping pipe 21, and the other end is connected with the second differential pressure sensor 26. One end of the fourth pressure tapping pipe 25 is connected with the second pressure tapping pipe 22, and the other end is connected with the second differential pressure sensor 26. The second differential pressure sensor 26 is also electrically connected with the control module 3, for calculating the air volume data according to the differential pressure signal output by the second differential pressure sensor 26. By setting two groups of differential pressure sensors and corresponding pressure tapping pipes, and combining the control of the subsequent control module 3 on the conduction state thereof, the component range pressure measurement can be realized, and the measurement requirements of different air volume ranges can be adapted.

[0038] In addition, the first pressure tapping pipe 21, the second pressure tapping pipe 22, the third pressure tapping pipe 24 and the fourth pressure tapping pipe 25 can be sample hoses, which are not specifically limited here.

[0039] Preferably, the first differential pressure sensor 23 and the second differential pressure sensor 26 are connected with the control module 3 through wires, which are not specifically limited here, such as shielded wires. The shielded wires can effectively prevent external electromagnetic interference and ensure the accuracy of the differential pressure signal transmission. The first differential pressure sensor 23 or the second differential pressure sensor 26 transmits the detected differential pressure signal to the control module 3. The control module 3 calculates the air volume data according to the formula based on the specific structure of the air volume meter stored in advance.

[0040] The control module 3 is the core control component of the entire air volume meter, which can include a single-chip microcomputer, a microprocessor and the like. Of course, the first differential pressure sensor 23 and the second differential pressure sensor 26 can also include a circuit for processing the differential pressure signal between the chip, which is not specifically limited here. The circuit is used to receive the differential pressure signal from the first differential pressure sensor 23 or the second differential pressure sensor 26 and calculate the air volume data according to the signals. At the same time, the control module 3 also has the function of selecting the conduction of the first pressure tapping pipe 21 and the second pressure tapping pipe 22 with the base body 11 or the conduction of the third pressure tapping pipe 24 and the fourth pressure tapping pipe 25 with the base body 11 according to the air volume range. The control module 3 integrates an intelligent algorithm therein, which can monitor the size of the differential pressure signal in real time and automatically switch different pressure tapping pipes and differential pressure sensor combinations according to a preset threshold value, realize component range pressure measurement, and thus improve the measurement accuracy and meet the measurement requirements in different air volume environments.

[0041] Preferably, referring to the accompanying drawings, Fig. 3As shown, the air volume meter is further provided with a first three-way valve 27 and a second three-way valve 28, the inlet of the first three-way valve 27 is connected with the first pressure tapping port 114, and the two outlets thereof are respectively connected with the first pressure tapping pipe 21 and the third pressure tapping pipe 24, the inlet of the second three-way valve 28 is connected with the second pressure tapping port 115, and the two outlets thereof are respectively connected with the second pressure tapping pipe 22 and the fourth pressure tapping pipe 25. The first three-way valve 27 and the second three-way valve 28 are both connected with the control module, the control module 3 controls the first three-way valve 27 to control the on-off between the first pressure tapping port 114 and the first pressure tapping pipe 21 and the third pressure tapping pipe 24, and controls the second three-way valve 28 to control the on-off between the second pressure tapping port 115 and the second pressure tapping pipe 22 and the fourth pressure tapping pipe 25.

[0042] In use, the application is first installed at a suitable measuring position to ensure that the windward surface and the leeward surface of the collection core can accurately obtain the gas pressure. When the air volume of the air inlet is small and belongs to a preset small range, the control module 3 controls the first three-way valve 27 to make the first pressure tapping port 114 conductive with the first pressure tapping pipe 21, and the second three-way valve 28 makes the second pressure tapping port 115 conductive with the second pressure tapping pipe 22, and the measurement is performed by the first differential pressure sensor 23. At this time, the gas enters the first space 112 through each first gas hole 121 on each first air inlet pipe 12, and then is transmitted from the first pressure tapping port 114 to the position connected with the first differential pressure sensor 23 through the first pressure tapping pipe 21, and simultaneously, the gas enters the second space 113 through each second gas hole 131 on each second air inlet pipe 13, and then is transmitted from the second pressure tapping port 115 to the position connected with the first differential pressure sensor 23 through the second pressure tapping pipe 22, and the first differential pressure sensor 23 transmits the detected pressure difference signal to the control module 3, and the control module 3 calculates the current air volume data according to the formula stored therein.

[0043] When the air volume of the air inlet increases to a preset large range, exceeding the accurate measurement range of the first differential pressure sensor 23, the control module 3 controls the first three-way valve 27 to make the first pressure tapping port 114 conductive with the third pressure tapping pipe 24, and the second three-way valve 28 makes the second pressure tapping port 115 conductive with the fourth pressure tapping pipe 25, and the measurement is performed by the second differential pressure sensor 26, and the gas is transmitted to the position connected with the second differential pressure sensor 26 through the fourth pressure tapping pipe 25 and the third pressure tapping pipe 24, and the second differential pressure sensor 26 transmits the pressure difference signal to the control module 3, and the control module 3 calculates the air volume data at this time according to the corresponding formula again.

[0044] The connection of the pipes of the application can be direct connection such as welding, gluing, integrated forming, plug-in connection, etc., or can be connected through a connecting piece, such as through a connector, a three-way valve, etc., and here no specific limitation is made, and the differential pressure sensor and the control module are directly or indirectly electrically connected.

[0045] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An air volume meter characterized by comprising: The application relates to a wind volume acquisition device. The acquisition module comprises a base body with a cavity, the cavity is divided into a first space and a second space which are not communicated with each other by a partition plate, a first pressure taking port is arranged on the upper wall of the base body with the first space, a second pressure taking port is arranged on the lower wall of the base body with the second space, a plurality of first air inlets and a plurality of second air inlets are arranged on the cavity wall of the base body, the first space obtains airflow from the air inlet direction through the first air inlets; the second space obtains airflow from the direction away from the air inlet direction through the second air inlets; each first air inlet is communicated with the first pressure taking port through the first space; each second air inlet is communicated with the second pressure taking port through the second space; The pressure measurement module comprises a first pressure taking pipe, a second pressure taking pipe and a first differential pressure sensor, the first pressure taking pipe is connected with the first pressure taking port and the first differential pressure sensor, the second pressure taking pipe is connected with the second pressure taking port and the first differential pressure sensor; The control module is electrically connected with the first differential pressure sensor and is configured to calculate the air volume data according to the differential pressure signal output by the first differential pressure sensor.

2. An air volume meter according to claim 1, wherein The acquisition module further comprises a plurality of first air inlets and a plurality of second air inlets, each first air inlet is communicated with each first air inlet one by one, each second air inlet is communicated with each second air inlet one by one, one end of each first air inlet away from the first air inlet is not communicated with the outside, one end of each second air inlet away from the second air inlet is not communicated with the outside.

3. An air volume meter according to claim 2, wherein The first air inlet is provided with a plurality of first air holes on the side facing the air inlet direction; the second air inlet is provided with a plurality of second air holes on the side away from the air inlet direction.

4. The air volume meter of claim 1, wherein The pressure measurement module comprises a third pressure taking pipe, a fourth pressure taking pipe and a second differential pressure sensor, one end of the third pressure taking pipe is connected with the first pressure taking port, and the other end is connected with the second differential pressure sensor; One end of the fourth pressure taking pipe is connected with the second pressure taking port, and the other end is connected with the second differential pressure sensor.

5. An air volume meter according to claim 4, wherein The second differential pressure sensor is electrically connected with the control module.

6. An air volume meter according to claim 4, wherein Further comprising a first three-way valve and a second three-way valve, the inlet of the first three-way valve is connected with the first pressure taking port, two outlets of the first three-way valve are connected with the first pressure taking pipe and the third pressure taking pipe respectively; the inlet of the second three-way valve is connected with the second pressure taking port, two outlets of the second three-way valve are connected with the second pressure taking pipe and the fourth pressure taking pipe respectively; The first three-way valve and the second three-way valve are connected with the control module, the control module controls the on-off between the first pressure taking port and the first pressure taking pipe and the third pressure taking pipe through the first three-way valve; the control module controls the on-off between the second pressure taking port and the second pressure taking pipe and the fourth pressure taking pipe through the second three-way valve.

7. An air volume meter according to claim 2, wherein The first air inlet and the second air inlet are symmetrically distributed along the circumference of the base body.

8. The air volume meter of claim 1, wherein, The first pressure taking port and the second pressure taking port are oppositely arranged.

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