A capacitive gas flow meter

Abstract

The present invention relates to the field of flow measurement technology, and in particular to a capacitive gas flowmeter, which comprises a collection component, a measuring component and a circuit control module, wherein the circuit control module is connected to the measuring component through a signal, the collection component comprises a main pipe and an inner pipe arranged in the main pipe, and the main pipe and the inner pipe are independently arranged, the measuring component comprises a test chamber body, a compensation chamber body and a cover plate assembly covered on the test chamber body, the air inlet channel of the main pipe is connected to the test chamber body, and the inner pipe is connected to the compensation chamber body; the capacitive gas flowmeter provided by the present invention can accurately measure the flow of various gases in flow channels such as circular pipes and rectangular pipes, and is used for accurately measuring the gas flow in the pipeline, and the flowmeter is relatively independent of the system to be measured when measuring the flow of the system to be measured, and will not affect the internal environment of the system to be measured.

Description

Technical Field

[0001] The present invention relates to the technical field of flow measurement, and in particular to a capacitive gas flow meter. Background Art

[0002] Capacitive film gas flowmeter is a flowmeter used for precise measurement of gas flow in pipelines. Capacitive film gas flowmeter mainly consists of two parts, the first part is the sensor collection pipeline assembly; the second part is the measurement assembly that obtains the output electrical signal caused by the pressure difference between the two ends of the capacitor diaphragm deformation. When the gas flows in the forward direction, it first enters the collection pipeline. Over time, the gas diffuses into the entire system, and the measurement chamber and the compensation chamber form a pressure difference. When it reaches the capacitor film, it becomes a steady-state flow and measures the gas flow at this time. Capacitive film gas flowmeter can accurately measure the flow of various gases in circular pipes, rectangular pipes and other flow channels. Capacitive film flowmeter is widely used in power plants, petrochemicals, metallurgy, water treatment, fine chemicals, nuclear industry and environmental protection industries, providing accurate flow metering instruments for various industries to ensure safe production. In the prior art, the reverse detection signal is small due to different gas fluxes, which affects the stability and accuracy of the sensor measurement assembly. In the prior art, there will be large particulate matter, aerosols and some interfering gases in the measurement environment that interfere with the normal operation of the sensor and reduce the life of the sensor. Patent document with application number 201521027763.1 discloses a device for measuring gas flow in oilfield gas storage reservoirs. The temperature difference is used to obtain the temperature of each point on the inner wall of the gas test channel through a temperature sensor array, and the gas flow is obtained by instrument calibration. The measurement result is inaccurate. Summary of the invention

[0003] In order to solve the problem of inaccurate gas flow measurement in the prior art, the present invention provides a capacitive gas flow meter.

[0004] In order to achieve the above-mentioned purpose, the present invention proposes a capacitive gas flowmeter, comprising: a collection component, a measuring component and a circuit control module, the circuit control module is connected to the measuring component through a signal, the collection component comprises a main pipe and an inner pipe arranged in the main pipe, and the main pipe and the inner pipe are arranged independently of each other, the measuring component comprises a test chamber body, a compensation chamber body and a cover plate assembly covered on the test chamber body, the air inlet channel of the main pipe is connected to the test chamber body, and the inner tube is connected to the compensation chamber body.

[0005] As an optional implementation, in the capacitive gas flowmeter provided by the present invention, at least two particle catchers are provided between the inner wall of the main pipe and the outer wall of the inner pipe, and the particle catchers are sleeved on the outer side of the inner pipe.

[0006] As an optional implementation, in the capacitive gas flowmeter provided by the present invention, the particle trap is in the shape of a circular column.

[0007] As an optional implementation, in the capacitive gas flowmeter provided by the present invention, a gap is provided in the particle trap, the gaps of two adjacent particle traps are arranged correspondingly, and a filter element is provided in the gap.

[0008] As an optional embodiment, in the capacitive gas flowmeter provided by the present invention, a plurality of first air flow inlets are opened on the side of the main pipe to connect to the air inlet channel of the main pipe, and a second air flow inlet is opened at a corresponding position on the main pipe facing away from the first air flow inlet, and the second air flow inlet is connected to the inner pipe.

[0009] As an optional embodiment, in the capacitive gas flowmeter provided by the present invention, the measuring component also includes an instrument seat arranged in the test chamber, the instrument seat has a built-in accommodating cavity, and the instrument seat has a plurality of first through holes connected to the test chamber.

[0010] As an optional embodiment, in the capacitive gas flowmeter provided by the present invention, the measuring component also includes a flat plate capacitor, the flat plate capacitor includes a fixed electrode and a capacitor diaphragm, the fixed electrode and the capacitor diaphragm are installed in the accommodating cavity of the instrument base, and the capacitor diaphragm is arranged at the lower end of the fixed electrode, a second through hole connected to the accommodating cavity is opened on the fixed electrode, the upper end surface of the capacitor diaphragm is connected to the test cavity body, and the lower end surface of the capacitor diaphragm is connected to the compensation cavity body.

[0011] As an optional implementation, in the capacitive gas flow meter provided by the present invention, the capacitive gas flow meter further includes a shell, and the shell is arranged on the cover plate assembly.

[0012] As an optional implementation, in the capacitive gas flowmeter provided by the present invention, a data interface connector is provided on the housing, and the data interface connector is signal-connected to the circuit control module.

[0013] As an optional implementation, in the capacitive gas flowmeter provided by the present invention, a flange is connected to the outer side of the test chamber body.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: in the capacitive gas flowmeter provided by the present invention, the flowmeter is used to accurately measure the gas flow in the pipeline; the air inlet channel of the main pipe is connected to the test chamber cavity, and the air inlet channel of the inner tube is connected to the compensation chamber cavity, so as to solve the problem that the reverse detection signal is small due to different gas fluxes, affecting the stability and accuracy of the sensor; by setting a particle catcher, the problem of large particulate matter, aerosols and some interfering gases appearing in the measurement environment of the flowmeter interfering with the normal operation of the sensor and shortening the life of the sensor is solved; the capacitive gas flowmeter provided by the present invention can accurately measure the flow of various gases in flow channels such as circular pipes and rectangular pipes, and is used to accurately measure the gas flow in the pipeline. When the flowmeter measures the flow of the system to be measured, it is relatively independent of the system to be measured and will not affect the internal environment of the system to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a capacitive gas flow meter provided by the present invention;

[0017] Figure 2 This is a cross-sectional schematic diagram of the capacitive gas flow meter provided by the present invention.

[0018] [Description of Reference Numerals]

[0019] 1: collection component; 11: main pipe; 111: air inlet; 112: first air flow inlet; 12: inner pipe; 121: second air flow inlet;

[0020] 2: measuring assembly; 21: test chamber body; 22: compensation chamber body; 23: cover assembly; 24: instrument seat; 25: accommodating chamber; 26: first through hole; 27: flat plate capacitor; 271: fixed plate; 272: capacitor diaphragm; 28: second through hole;

[0021] 3: Circuit control module;

[0022] 4: particle trap; 41: filter element;

[0023] 5: Housing; 6: Data interface connector; 7: Flange. DETAILED DESCRIPTION

[0024] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0025] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0026] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention provides a capacitive gas flow meter, such as Figure 1 As shown, it comprises: a collection component 1, a measurement component 2 and a circuit control module 3, wherein the circuit control module 3 is connected to the measurement component 2 through signals, the collection component 1 comprises a main pipe 11 and an inner pipe 12 arranged in the main pipe 11, and the main pipe 11 and the inner pipe 12 are arranged independently of each other, the measurement component 2 comprises a test chamber body 21, a compensation chamber body 22 and a cover plate assembly 23 covered on the test chamber body 21, the air inlet channel 111 of the main pipe 11 is connected to the test chamber body 21, and the inner pipe 12 is connected to the compensation chamber body 22. Among them, the outer side of the test chamber body 21 is connected with a flange 7 for connecting with the pipeline to be tested.

[0029] In the capacitive gas flowmeter provided by the present invention, the air inlet channel 111 of the main pipe 11 is connected to the test chamber body 21, and the air inlet channel 111 of the inner pipe 12 is connected to the compensation chamber body 22, so as to solve the problem that the reverse detection signal is small due to different gas fluxes, which affects the stability and accuracy of the sensor; by setting a particle catcher 4, the problem of interference with the normal operation of the sensor and shortening the life of the sensor caused by large particulate matter, aerosols and some interfering gases in the measurement environment of the flowmeter is solved; the capacitive gas flowmeter provided by the present invention can accurately measure the flow of various gases in flow channels such as circular pipes and rectangular pipes, and is used for accurately measuring the gas flow in the pipeline. When the flowmeter measures the flow of the system to be measured, it is relatively independent of the system to be measured and will not affect the internal environment of the system to be measured.

[0030] As an optional embodiment, in the capacitive gas flowmeter provided by the present invention, a plurality of first airflow inlets 112 are provided on the side of the main pipe 11 to connect the air inlet channel 111 of the main pipe 11, and a second airflow inlet 121 is provided on the corresponding position of the main pipe 11 opposite to the first airflow inlet 112, and the second airflow inlet 121 is connected to the inner pipe 12. The main pipe 11 of the sensor collection element part has a plurality of first airflow inlets 112 of the same size in the incoming flow direction of the measured gas, and the sum of their areas is the incoming flow channel area; the main pipe 11 has a second airflow inlet 121 in the backflow direction of the measured gas, and the second airflow inlet 121 is directly connected to the inner pipe 12 and is not conductive with the inside of the main pipe 11, and the area of ​​the second airflow inlet 121 is the backflow channel area. The error signal, the beneficial signal and the reaction time are determined according to the structure of the sensor itself. According to the research of the present invention, the ratio of the error signal to the beneficial signal is related to the ratio of the area of ​​the incoming flow channel and the backflow channel of the main pipe 11. When the area of ​​the incoming flow channel of the main pipe 11: the area of ​​the backflow channel of the main pipe 11 is between 14:1 and 50:1, the error signal can be lower than the threshold voltage ±0.5V, the beneficial signal is greater than 4.2V and the reaction time is less than 1s. At this time, the error signal voltage will not exceed the threshold voltage to cause a false alarm; the generated beneficial signal is large and easy to be detected, which significantly improves the stability and accuracy of the sensor detection. When the area of ​​the incoming flow channel of the main pipe 11: the area of ​​the backflow channel of the main pipe 11 is less than 14:1, the beneficial signal will be too small, which is not conducive to the collection of the beneficial signal, and the reaction time is long; when the area of ​​the incoming flow channel of the main pipe 11: the area of ​​the backflow channel of the main pipe 11 is greater than 50:1, the reaction time is long, the error signal is too large, and it exceeds the threshold voltage of the sensor alarm, causing the sensor to falsely alarm and affect normal safety production.

[0031] In addition, the measuring assembly 2 further comprises an instrument seat 24 disposed in the test chamber body 21 . The instrument seat 24 has a built-in accommodating cavity 25 . The instrument seat 24 is provided with a plurality of first through holes 26 communicating with the test chamber body 21 .

[0032] Furthermore, the measuring component 2 also includes a flat plate capacitor 27, which includes a fixed electrode 271 and a capacitor diaphragm 272. The fixed electrode 271 and the capacitor diaphragm 272 are installed in the accommodating cavity 25 of the instrument seat 24, and the capacitor diaphragm 272 is arranged at the lower end of the fixed electrode 271. The fixed electrode 271 is provided with a second through hole 28 connected to the accommodating cavity 25. The upper end surface of the capacitor diaphragm 272 is connected to the test cavity body 21, and the lower end surface of the capacitor diaphragm 272 is connected to the compensation cavity body 22. Specifically, the test chamber body 21 and the compensation chamber body 22 are separated by a capacitor diaphragm 272. The capacitor diaphragm 272 adopts a specific heat treatment and aging treatment process. The fixed plate 271 above the capacitor diaphragm 272 and the capacitor diaphragm 272 form a flat capacitor 27. According to the change of the pressure difference between the test chamber and the compensation chamber, the capacitor diaphragm 272 produces different deformations. When the gas in the pipeline flows in from the first air flow inlet 112 and the gas suddenly flows in from the second air flow inlet 121, the capacitor film produces different deformations and different capacitance values, and outputs a voltage signal after conversion by the circuit control module 3. The data interface connector 6 set on the shell 5 is connected to the circuit control module 3 signal, and calculates the gas flow rate according to the ideal gas equation, the internal structure parameters of the flowmeter, the deformation law parameters of the special capacitor diaphragm 272, etc. The flowmeter is used to accurately measure the gas flow rate in the pipeline. It can measure the flow rate of the gas in the first direction while detecting the airflow in the opposite direction and issuing an early warning. When the gas flows in the opposite direction, a DC voltage electrical signal is generated to serve as a warning.

[0033] like Figure 2As shown, in the capacitive gas flowmeter provided by the present invention, at least two particle catchers 4 are arranged between the inner wall of the main pipe 11 and the outer wall of the inner pipe 12, and the particle catchers 4 are in the shape of an annular column, and are sleeved on the outer side of the inner pipe 12; a gap is arranged in the particle catcher 4, and the gaps of two adjacent particle catchers 4 are arranged correspondingly, and a filter element 41 is arranged in the gap. The particle catcher 4 is arranged between the inner wall of the main pipe 11 and the outer wall of the inner pipe 12 in a transitional matching manner, and the filter element 41 inside the particle catcher 4 is replaceable, which is suitable for airflow monitoring requirements under various working conditions; and a controllable resistance wire original is also arranged in the hollow ceramic base frame of the particle catcher 4, which can be heated to 400°C without disassembly to achieve regeneration of the filter element 41 of the particle catcher 4. The particle catcher 4 with an annular columnar hollow ceramic base structure can effectively filter out large particulate matter, aerosols and some interfering gases in the measurement environment that interfere with the normal operation of the sensor, thereby improving the sensor life, which can reach 20 years. Among them, the heating time of the sensor after being connected is not less than 1 hour, the working state of the sensor measurement component 2 is vertical, the connector is facing upward, and the vertical deviation is not greater than 5°; the pipeline gas pressure of the measurement environment is not greater than 11.97KPa, and when the flow density of the prohibited reverse direction airflow increases from 0 to 5mg·cm-2·s-1, the time for the output voltage of the sensor measurement component 2 to increase from 0 to 24mV does not exceed 4s.

[0034] As an optional implementation, in the capacitive gas flow meter provided by the present invention, the capacitive gas flow meter further includes a housing 5 , and the housing 5 is disposed on the cover plate assembly 23 .

[0035] It should be understood that the above description of the specific embodiments of the present invention is only for illustrating the technical route and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but the present invention is not limited to the above specific implementation methods. Any changes or modifications made within the scope of the claims of the present invention should be included in the protection scope of the present invention.

Claims

1. A capacitive gas flow meter, characterized in that: The invention comprises a collection component (1), a measuring component (2) and a circuit control module (3), wherein the circuit control module (3) is connected to the measuring component (2) via signals, the collection component (1) comprises a main pipe (11) and an inner pipe (12) arranged in the main pipe (11), and the main pipe (11) and the inner pipe (12) are arranged independently of each other, the measuring component (2) comprises a test chamber body (21), a compensation chamber body (22) and a cover plate component (23) arranged on the test chamber body (21), the air inlet channel (111) of the main pipe (11) is in communication with the test chamber body (21), and the inner pipe (12) is in communication with the compensation chamber body (22).

2. The capacitive gas flow meter according to claim 1, characterized in that: At least two particle catchers (4) are arranged between the inner wall of the main pipe (11) and the outer wall of the inner pipe (12), and the particle catchers (4) are sleeved on the outer side of the inner pipe (12).

3. The capacitive gas flow meter according to claim 2, characterized in that: The particle catcher (4) is in the shape of a circular column.

4. The capacitive gas flow meter according to claim 3, characterized in that: A gap is provided in the particle trap (4), the gaps of two adjacent particle traps (4) are arranged correspondingly, and a filter element (41) is provided in the gap.

5. The capacitive gas flow meter according to any one of claims 1 to 4, characterized in that: A plurality of first airflow inlets (112) are provided on the side of the main pipe (11) to connect with the air inlet channel (111) of the main pipe (11); a second airflow inlet (121) is provided at a corresponding position of the main pipe (11) facing away from the first airflow inlet (112); and the second airflow inlet (121) is butt-jointed with the inner pipe (12).

6. The capacitive gas flow meter according to any one of claims 1 to 4, characterized in that: The measuring assembly (2) further comprises an instrument seat (24) arranged in the test chamber body (21), the instrument seat (24) having a built-in accommodating cavity (25), and the instrument seat (24) having a plurality of first through holes (26) in communication with the test chamber body (21).

7. The capacitive gas flow meter according to claim 6, characterized in that: The measuring assembly (2) further comprises a flat plate capacitor (27), the flat plate capacitor (27) comprising a fixed electrode plate (271) and a capacitor diaphragm (272), the fixed electrode plate (271) and the capacitor diaphragm (272) being installed in a receiving cavity (25) of the instrument seat (24), and the capacitor diaphragm (272) being arranged at the lower end of the fixed electrode plate (271), the fixed electrode plate (271) being provided with a second through hole (28) communicating with the receiving cavity (25), the upper end surface of the capacitor diaphragm (272) being communicated with the test cavity body (21), and the lower end surface of the capacitor diaphragm (272) being communicated with the compensation cavity body (22).

8. The capacitive gas flow meter according to any one of claims 1 to 4, characterized in that: The capacitive gas flow meter further comprises a housing (5), wherein the housing (5) is arranged on the cover plate assembly (23).

9. The capacitive gas flow meter according to claim 8, characterized in that: The housing (5) is provided with a data interface connector (6), and the data interface connector (6) is signal-connected to the circuit control module (3).

10. The capacitive gas flow meter according to any one of claims 1 to 4, characterized in that: The outer side of the test chamber body (21) is connected with a flange (7).

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