Electrode air flow sensor coupling cleaning structure

Abstract

The application relates to the technical field of gas detection, in particular to an electrode type airflow sensor coupling cleaning structure which comprises an air duct assembly, an adsorption assembly and a detection channel; the air duct assembly is arranged in a blocking cavity; the adsorption assembly is connected with the air duct assembly; the detection channel is connected with the air duct assembly; the flue gas entering into the sensor is subjected to cyclone, and at the same time, the particulate matters are made to carry negative charges by using an electric field, so that the particulate matters are subjected to electrostatic force in the same direction as centrifugal force, submicron-level particulate matters can be effectively separated, meanwhile, a Faraday cage is formed under the grounding effect of a collection electrode, the influence of an electric field on a working electrode is shielded, NO2 affecting detection precision in flue gas is eliminated by using high temperature of the flue gas and an activated carbon layer, and detection precision is guaranteed; the problems that micron-level and submicron-level particulate matters are difficult to separate in a mechanical way and that alternating electric field separation of particulate matters affects normal detection of the sensor are solved.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and more specifically to a coupling and cleaning structure for an electrode-type airflow sensor. Background Technology

[0002] Electrode-type airflow sensors are sensors that detect gas concentration by generating an electric current signal through the oxidation-reduction reaction of gas on the electrode surface. Due to increasingly serious air pollution, electrode-type airflow sensors are currently mostly used in chemical plants or flues to detect gases that need to be monitored. Only when the composition of the gas meets the standards can it be discharged into the atmosphere.

[0003] When electrode-type airflow sensors are used for flue gas emission monitoring, the presence of tiny particles in the flue gas causes some of these particles to adhere to the electrode surface of the sensor as the flue gas passes through. This significantly reduces the sensor's detection accuracy. Furthermore, filter-like structures are not suitable for airflow sensors to prevent particle entry. Filters capable of capturing micron-sized particles have high air resistance, and these filters quickly become saturated and clogged when exposed to high concentrations of particles, requiring frequent replacement due to their difficulty in cleaning. Existing technologies have proposed effective solutions to this problem, such as the gas flow sensor and gas flow detection method described in patent publication CN117490785A. By incorporating a self-cleaning chip and an auxiliary flow channel, the paired electrodes on the self-cleaning chip can generate an alternating electric field. This alternating electric field causes gas particles to enter the auxiliary flow channel, thereby preventing tiny particles from adhering to the electrodes of the detection chip.

[0004] While existing technologies have solved the problem of fine particulate matter in flue gas easily adhering to the electrode surface of the detection chip, the following issues remain: When using an alternating electric field to drive particle movement, the driving force on the particles is proportional to the amount of charge and the magnitude of the electric field strength. For particles smaller than 1μm in flue gas, their charge is low, requiring a larger electric field strength to move them. However, a large electric field strength and an alternating electric field frequency close to the operating frequency can interfere with the detection electrode, causing fluctuations in the sensor output signal and affecting the accurate monitoring of gas concentration. For particles larger than 10μm in flue gas, they will drift randomly due to inertia, escaping the electric field control. When large particles are not discharged but instead impact the electrode surface under the driving force of the electric field, the detection accuracy will also decrease. Furthermore, in CO concentration detection, the high-voltage electric field will ionize the gas, producing O3 and NO2, which can affect CO concentration detection, further reducing the detection accuracy.

[0005] In view of the above, in order to overcome the above technical problems, the present invention designs an electrode-type airflow sensor coupling cleaning structure. Summary of the Invention

[0006] This invention provides an electrode-type airflow sensor coupling cleaning structure, solving the problems of the difficulty in mechanically separating micron- and submicron-sized particles and the impact of alternating electric fields on normal sensor detection. By setting up an Archimedean spiral air cavity, the flue gas enters the spiral air cavity and flows spirally with a gradually increasing velocity, causing the particles to be subjected to centrifugal force. The central electrode at the center of the spiral air cavity generates a corona discharge, causing the particles to become negatively charged. The inner wall of the spiral air cavity is a grounded collecting electrode. At this time, the particles will be subjected to an electrostatic force in the same direction as the centrifugal force, ensuring that submicron-sized particles can be effectively separated. At the same time, the collecting electrode forms a Faraday cage under the grounding effect, shielding the electric field from the influence of the working electrode. Furthermore, due to the high temperature of the flue gas itself, the O3 and NO2 generated by ionization, as well as the NO2 originally in the flue gas, react with the activated carbon layer in the detection channel to eliminate the influence of O3 and NO2 on CO detection, further improving the detection accuracy.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An electrode-type airflow sensor coupling cleaning structure includes a sensor housing, a working chamber, a circuit board, and a working electrode; it also includes a barrier chamber, an air duct assembly, an adsorption assembly, and a detection channel; the barrier chamber is located inside the sensor housing; the air duct assembly is disposed within the barrier chamber, and flue gas enters the air duct assembly and undergoes swirling upward motion; the adsorption assembly is connected to the air duct assembly, and after the flue gas enters, the adsorption assembly is energized to form an electric field within the air duct assembly, causing the particulate matter in the flue gas to be subjected to an electric field force in the same direction as the swirling centrifugal force; the detection channel is connected to the air duct assembly, and the detection channel connects the barrier chamber and the working chamber.

[0009] Preferably, the air duct assembly includes a spiral air cavity, an air inlet channel, a spiral plate, and a collection groove; the spiral air cavity is formed inside the barrier cavity; the air inlet channel is connected between the spiral air cavity and the outer wall of the barrier cavity, and is tangentially connected to the spiral air cavity; the spiral plate is arranged in a spiral array inside the spiral air cavity; and the collection groove is located at the bottom of the spiral air cavity.

[0010] In the above scheme, after the flue gas enters the spiral cavity, it can undergo swirling motion, and the spiral plate can enhance the swirling motion and assist the flue gas to rise. During this process, the particulate matter will move towards the inner wall of the spiral cavity under the action of centrifugal force and gravity, and will fall into the collection tank under the action of gravity, thereby completing the separation from the flue gas.

[0011] Preferably, the cross-section of the spiral air cavity is an Archimedean spiral structure; the size of the spiral plate decreases sequentially along the air inlet direction and spirals upward.

[0012] In the above scheme, the Archimedes spiral structure can gradually increase the flue gas velocity and enhance the swirling effect of the flue gas, so that the centrifugal force on the particulate matter gradually increases, thereby effectively separating the particulate matter from the flue gas. The flue gas itself is a high-temperature gas and flows upward. The spiral plate can match the flue gas flow direction to further increase the flue gas velocity, thereby improving the separation effect.

[0013] Preferably, the cross-sectional area of ​​the air inlet channel gradually decreases along the air inlet direction, and a coarse filter screen is provided at the connection position between the air inlet channel and the outer wall of the barrier cavity.

[0014] In the above solution, the large opening of the air inlet channel ensures that the flue gas can easily enter. After entering, the flow velocity will gradually increase as the flow area decreases. The coarse filter can filter out excessively large particles. These large particles are easier to clean than micron-sized particles. Furthermore, the coarse filter can be designed to be detachable for easy cleaning and replacement. This reduces the content of large particles in the flue gas entering the spiral air chamber, thereby reducing the amount of particles accumulated in the spiral air chamber after each use and reducing the frequency of disassembly and cleaning of the spiral air chamber.

[0015] Preferably, the adsorption assembly includes a collecting electrode, a central electrode, a power supply module, and a DC boost module; the collecting electrode is connected to the inner wall of the spiral air cavity; the central electrode is located at the center of the spiral air cavity; the power supply module is mounted on a circuit board; and the DC boost module is mounted on the circuit board and electrically connected to the power supply module and the central electrode.

[0016] In the above scheme, when a sufficiently high negative voltage is applied to the central electrode, the surrounding air molecules will ionize to generate free electrons and negative ions. These electrons and negative ions will attach to the particles, making them negatively charged. The collecting electrode, by grounding (or applying a positive high voltage), can subject the charged particles to Coulomb force (electrostatic force), firmly adsorbing them onto the inner wall of the collecting electrode. The adsorption effect generated by electrostatic force can effectively prevent large particles from bouncing off the wall and returning to the working electrode position with the gas. For submicron-sized particles, the combined effect of electrostatic adsorption and centrifugal force can greatly improve the separation effect. Compared with simple centrifugal separation, particles adsorbed on the collecting electrode wall by electrostatic force are less likely to be re-entrained by the airflow, significantly reducing the "re-entry phenomenon". In addition, the implementation of two separation mechanisms in the same cavity can reduce the size of the sensor and improve its integration.

[0017] Preferably, the collecting electrode is made of stainless steel and is grounded.

[0018] In the above scheme, the grounded collecting electrode can adsorb negatively charged particles. At the same time, since the cavity formed by the collecting electrode is grounded, it can form a Faraday cage, which confines the high-voltage electric field within this area. In addition, the detection channel is connected to the collecting electrode and is also grounded. There is a certain distance between the detection channel and the working electrode, which allows the electric field to decay exponentially in the detection channel, ensuring that it will not affect the normal detection of the working electrode.

[0019] Preferably, the central electrode includes an insulating column and a discharge tungsten wire; the insulating column is installed at the center of the spiral air cavity; the discharge tungsten wire is installed inside the insulating column, and the portion extending out of the insulating column has a sharp shape and is arranged in a multi-layer circumferential array; the spiral plate and the detection channel are both made of insulating material.

[0020] In the above scheme, the extended part of the discharge tungsten wire has a sharp structure, low corona initiation voltage, and stable discharge, which can ensure the generation of corona and thus effectively generate free electrons, allowing the free electrons to attach to the particles. In addition, the multi-layer circumferential array can make the electric field coverage wide and can charge the particles evenly and continuously. The insulating pillar is made of insulating material to prevent high voltage short circuits and breakdown. Furthermore, the insulation between the central electrode and the collecting electrode can prevent short circuits and ensure the normal operation of the entire system.

[0021] Preferably, the detection channel includes a channel body and an activated carbon layer; the channel body is connected between the working chamber and the spiral air chamber; the activated carbon layer is disposed within the channel body.

[0022] In the above scheme, the gas after electrostatic adsorption and spiral separation will enter the detection channel. The gas will pass through the activated carbon layer to adsorb the remaining particulate matter for the last time and slow down the flow rate of the flue gas, ensuring that the flue gas reaching the working electrode can make full contact with the working electrode, thereby ensuring detection accuracy. During the ionization process, some O3 and NO2 will be generated. Since the flue gas temperature is relatively high, and O3 will decompose rapidly and cannot exist stably above 100°C, it will not affect the CO concentration monitoring. NO2 will react with the activated carbon layer under high temperature conditions and become NO and N2, which have no effect on CO monitoring.

[0023] Preferably, the channel body includes a bending section and a diffuser section; the bending section is connected to the spiral air cavity; and the diffuser section is connected between the bending section and the working cavity.

[0024] In the above scheme, the bending section can enhance the electric field shielding effect, the diffusion section can slow down the flue gas flow speed, and make the flue gas evenly distributed, increasing the contact area and contact uniformity with the working electrode.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. Compared to existing electrode-type airflow sensors, this invention utilizes an Archimedean spiral structure with a spiral cavity and spiral plate to force the flue gas into an accelerated swirling flow, thereby enhancing the centrifugal force on particulate matter in the flue gas and improving the separation effect between particulate matter and flue gas. A collecting electrode is set on the inner wall of the spiral cavity, and a central electrode is set at the center of the spiral cavity. By applying a sufficiently high negative voltage to the central electrode to generate a corona discharge, the particulate matter in the flue gas can be negatively charged. The negatively charged particulate matter can be attracted by the collecting electrode, further improving the separation effect. Under the combined action of electrostatic adsorption force and centrifugal force, it can be ensured that large particulate matter is electrostatically adsorbed on the wall of the collecting electrode and is difficult to be re-entered or rebounded by the airflow, significantly reducing the "re-entry phenomenon". For submicron-sized particulate matter, the separation effect can be greatly improved, ensuring that the flue gas reaching the working electrode does not carry particulate matter and avoiding the decrease in detection accuracy caused by particulate matter adhering to the working electrode.

[0027] 2. By grounding the collecting electrode, the present invention can form a Faraday cage, which confines the high-voltage electric field within this area. The "exit" of the entire Faraday cage is the detection channel. There is a certain distance between the detection channel and the working electrode, and the bends in the detection channel can enhance the electric field shielding effect, so that the electric field will exhibit exponential decay in the detection channel, ensuring that it will not affect the normal detection of the working electrode, thereby ensuring the accuracy of the working electrode in detecting CO concentration.

[0028] 3. This invention incorporates an activated carbon layer within the channel body, enabling a final adsorption of residual particulate matter in the flue gas, ensuring cleaner flue gas. The activated carbon layer also slows the flow rate of the flue gas, ensuring sufficient contact between the flue gas reaching the working electrode and the electrode, thereby guaranteeing detection accuracy. Under the high temperature conditions of the flue gas itself, O3 decomposes rapidly, and the activated carbon catalyzes this decomposition. The flue gas flowing out after the bend will no longer contain O3. NO2, under high temperature conditions, reacts with the activated carbon layer to become NO and N2, which have no effect on CO detection. This process also removes the NO2 originally present in the flue gas, further improving the accuracy of CO concentration detection. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is an overall structural diagram of the present invention;

[0031] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0032] Figure 3 This is a cross-sectional view of the air duct assembly of the present invention;

[0033] Figure 4 This is a cross-sectional view of the central electrode of the present invention;

[0034] Figure 5 for Figure 4 Enlarged view of the structure at point A in the middle;

[0035] Figure 6 This is an exploded view of the present invention;

[0036] Figure 7 This is a schematic diagram of the detection channel structure of the present invention;

[0037] Figure 8 This is a diagram showing the flue gas flow direction when the present invention is used;

[0038] In the diagram: 1. Sensor housing; 2. Working chamber; 3. Circuit board; 4. Working electrode; 5. Barrier chamber; 6. Air duct assembly; 61. Spiral air chamber; 62. Air inlet channel; 621. Coarse filter; 63. Spiral plate; 64. Collection tank; 7. Adsorption assembly; 71. Collection electrode; 72. Central electrode; 721. Insulating column; 722. Discharge tungsten wire; 73. Power module; 74. DC boost module; 8. Detection channel; 81. Channel body; 811. Bending section; 812. Diffusion section; 82. Activated carbon layer. Detailed Implementation

[0039] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0040] Please see Figures 1 to 8 This invention provides an electrode-type airflow sensor coupling cleaning structure, the technical solution of which is as follows:

[0041] As a specific embodiment of the present invention, refer to Figure 1 and Figure 2An electrode-type airflow sensor coupling cleaning structure is disclosed, comprising a sensor housing 1, a working chamber 2, a circuit board 3, and a working electrode 4; it also includes a barrier cavity 5, an air duct assembly 6, an adsorption assembly 7, and a detection channel 8; the barrier cavity 5 is located inside the sensor housing 1; the air duct assembly 6 is disposed within the barrier cavity 5, and flue gas enters the air duct assembly 6 and undergoes swirling upward motion; the adsorption assembly 7 is connected to the air duct assembly 6, and after the flue gas enters, the adsorption assembly 7 is energized to form an electric field within the air duct assembly 6, causing the particulate matter in the flue gas to be subjected to an electric field force in the same direction as the swirling centrifugal force; the detection channel 8 is connected to the air duct assembly 6, and the detection channel 8 connects the barrier cavity 5 and the working chamber 2.

[0042] As a specific embodiment of the present invention, refer to Figure 2 and Figure 3 The air duct assembly 6 includes a spiral air chamber 61, an air inlet channel 62, a spiral plate 63, and a collection trough 64. The spiral air chamber 61 is located within the barrier cavity 5. The air inlet channel 62 connects the spiral air chamber 61 and the outer wall of the barrier cavity 5, and is tangentially connected to the spiral air chamber 61. The spiral plate 63 is arranged in a spiral array within the spiral air chamber 61. The collection trough 64 is located at the bottom of the spiral air chamber 61. After the flue gas enters the spiral air chamber 61, it undergoes swirling motion, and the spiral plate 63 enhances the swirling motion and assists the flue gas to rise. During this process, particles are subjected to centrifugal force and gravity, moving towards the inner wall of the spiral air chamber 61 and falling into the collection trough 64 under gravity, thus separating from the flue gas. The spiral air chamber 61 can be designed as a detachable structure. After a period of use, the spiral air chamber 61 can be disassembled to remove particles from the collection trough 64, thereby reducing replacement costs.

[0043] As a specific embodiment of the present invention, refer to Figure 2 and Figure 3 The spiral air chamber 61 has an Archimedean spiral structure in cross-section; the size of the spiral plate 63 decreases sequentially along the air inlet direction and spirals upward. The Archimedean spiral structure allows the flue gas velocity to gradually increase and enhances the swirling effect of the flue gas, gradually increasing the centrifugal force on the particulate matter, thereby effectively separating the particulate matter from the flue gas. The flue gas itself is a high-temperature gas and flows upward; the spiral plate 63, in conjunction with the flue gas flow direction, further increases the flue gas velocity, thereby improving the separation effect.

[0044] As a specific embodiment of the present invention, refer to Figure 2 and Figure 3The cross-sectional area of ​​the air inlet channel 62 gradually decreases along the air inlet direction. A coarse filter 621 is provided at the connection between the air inlet channel 62 and the outer wall of the barrier cavity 5. The air inlet channel 62 has a large opening, which ensures that the flue gas can easily enter. After entering, the flow velocity will gradually increase due to the decrease in flow area. The coarse filter 621 can filter out excessively large particles. These large particles are easier to clean than micron-sized particles. Furthermore, the coarse filter 621 can be designed to be detachable for easy cleaning and replacement. This reduces the content of large particles in the flue gas entering the spiral air chamber 61, thereby reducing the amount of particles accumulated in the spiral air chamber 61 after each use and reducing the frequency of disassembly and cleaning of the spiral air chamber 61.

[0045] As a specific embodiment of the present invention, refer to Figure 3 , Figure 4 and Figure 6The adsorption assembly 7 includes a collecting electrode 71, a central electrode 72, a power supply module 73, and a DC boost module 74. The collecting electrode 71 is connected to the inner wall of the spiral air cavity 61. The central electrode 72 is located at the center of the spiral air cavity 61. The power supply module 73 is mounted on the circuit board 3. The DC boost module 74 is mounted on the circuit board 3 and electrically connected to the power supply module 73 and the central electrode 72. When a sufficiently high negative voltage is applied to the central electrode 72, the surrounding air molecules will ionize to generate free electrons and negative ions. These electrons and negative ions will attach to the particles, making them negatively charged. The collecting electrode 71, by grounding (or applying a positive high voltage), can subject the charged particles to Coulomb force (electrostatic force), firmly adsorbing them onto the inner wall of the collecting electrode 71. The adsorption effect generated by electrostatic force can effectively prevent large particles from hitting the wall and rebounding, causing the particles to return to the working electrode 4 with the gas. For submicron-sized particles, the electrostatic force... The combined effect of adsorption and centrifugal force significantly improves the separation effect. Compared to simple centrifugal separation, particles adsorbed by electrostatic force on the wall of the collecting electrode 71 are less likely to be re-entrained by the airflow, significantly reducing the "re-entry phenomenon." Furthermore, the implementation of two separation mechanisms within the same cavity reduces the size of the sensor and increases integration. The power module 73 (AC / DC module) converts alternating current to direct current, while the DC boost module 74 can boost the original low voltage to over 3kV, enabling the central electrode 72 to generate corona discharge. The collecting electrode 71 is made of stainless steel and is grounded. The grounded collecting electrode 71 can adsorb negatively charged particles. Since the cavity formed by the collecting electrode 71 is grounded, it forms a Faraday cage, confining the high-voltage electric field within this area. Furthermore, the detection channel 8, connected to the collecting electrode 71 and also grounded, maintains a certain distance from the working electrode 4, causing the electric field to decay exponentially within the detection channel 8, ensuring it does not affect the normal detection of the working electrode 4. The adsorption component 7 can be switched on and off in several ways. First, it can be manually controlled via the Internet of Things (IoT) to open when specific emissions need to be detected. Second, because the current generated by the central electrode 72 during corona discharge is only in the microampere range, the power consumption is very low even when it is constantly on, ensuring that particles are electrostatically adsorbed whenever flue gas enters. Third, an additional electrode can be set on an external sensor to detect CO; it automatically powers on and applies a negative voltage to the central electrode 72 whenever a sudden increase in concentration is detected.

[0046] As a specific embodiment of the present invention, refer to Figure 4 and Figure 5The central electrode 72 includes an insulating pillar 721 and a discharge tungsten filament 722. The insulating pillar 721 is installed at the center of the spiral air chamber 61. The discharge tungsten filament 722 is installed inside the insulating pillar 721, and the portion extending out of the insulating pillar 721 has a sharp shape and is arranged in a multi-layer circumferential array. The spiral plate 63 and the detection channel 8 are both made of insulating material. The sharp structure of the extended portion of the discharge tungsten filament 722 results in a low corona initiation voltage and stable discharge, ensuring the generation of corona and effectively generating free electrons that attach to the particulate matter. The multi-layer circumferential array provides a wide electric field coverage, allowing for uniform and continuous charging of the particulate matter. The insulating pillar 721, being made of insulating material, prevents high-voltage short circuits and breakdowns. Insulation between the central electrode 72 and the collecting electrode 71 prevents short circuits, ensuring the normal operation of the entire system. Here, the insulating pillar 721, spiral plate 63, and detection channel 8 can all be made of ceramic material. Ceramic material has good insulation capabilities and can withstand high temperatures, ensuring a long service life in high-temperature flue gas environments.

[0047] As a specific embodiment of the present invention, refer to Figure 7 and Figure 8The detection channel 8 includes a channel body 81 and an activated carbon layer 82. The channel body 81 is connected between the working chamber 2 and the spiral air chamber 61. The activated carbon layer 82 is disposed inside the channel body 81. Gas that has undergone electrostatic adsorption and spiral separation will enter the detection channel 8. The gas passes through the activated carbon layer 82, where it will adsorb the remaining particulate matter for the last time and slow down the flow rate of the flue gas, ensuring that the flue gas reaching the working electrode 4 can make sufficient contact with the working electrode 4, thereby ensuring detection accuracy. During ionization, some O3 and NO2 will be generated. Since the flue gas temperature is relatively high (around 200℃-350℃), and O3 decomposes rapidly and becomes unstable above 100℃, it will not affect CO concentration monitoring. NO2, however, will react with the activated carbon layer 82 at high temperatures, transforming into NO and N2, which have no effect on CO monitoring. The reaction begins above 100℃, with NO as the main product between 100℃ and 300℃, and NO and N2 as the main products above 300℃. Furthermore, this process can also... Effectively eliminates the influence of NO2 present in the flue gas on CO concentration monitoring (when using the redox reaction of the electrode to monitor CO concentration, it is mainly obtained by the change between the current value and the standard value. If NO2 is present, it will react with the working electrode 4 to generate a negative current, thereby canceling out part of the positive current signal generated by CO, thus interfering with the detection result); the channel body 81 includes a bending section 811 and a diffusion section 812; the bending section 811 is connected to the spiral air cavity 61; the diffusion section 812 is connected to the channel body between the bending section 811 and the working cavity 2. The bending section 811 can enhance the electric field shielding effect, so that the electric field can be fully attenuated. The diffusion section 812 can slow down the flue gas flow speed and make the flue gas evenly distributed, increasing the contact area and contact uniformity with the working electrode 4, thereby ensuring the accuracy of the detection result.

[0048] Workflow: After the flue gas enters the spiral vortex 61, it is accelerated and swirled, causing the particulate matter to be subjected to centrifugal force. At the same time, the central electrode 72 generates a corona discharge, causing the particulate matter to carry a negative charge. At this time, the particulate matter will be subjected to electrostatic adsorption force in the same direction as the centrifugal force and move towards the collecting electrode 71. After separating the particulate matter, the flue gas enters the detection channel 8, where O3 and NO2 that will affect the detection results are eliminated and the flow speed is slowed down. Finally, it enters the working chamber 2 and comes into contact with the working electrode 4 for detection.

[0049] The flue gas undergoes initial sieving through the coarse filter 621, removing large particles. These particles then enter the spiral cavity 61 through the inlet channel 62. Since the flow area of ​​the inlet channel 62 gradually decreases along the airflow direction, the gas undergoes initial acceleration. Upon entering the spiral cavity 61, the flue gas is forced into a swirling flow under the guidance of the Archimedean spiral structure and the spiral plate 63, and the flow velocity gradually increases. During this swirling process, the power module 73 converts AC to DC, which is then boosted to over 3kV by the DC boost module 74. A negative voltage is applied to the central electrode 72, causing the tungsten filament 722 to generate a corona discharge, ionizing the surrounding air to produce free electrons and negative ions. These electrons and negative ions attach to the particles, giving them a negative charge. The collecting electrode 71, grounded, allows the charged particles to be subjected to Coulomb forces, thus firmly adhering to the inner wall of the collecting electrode 71, effectively preventing large particles from colliding with it. The impact on the wall causes the particles to bounce back and return to the working electrode 4 with the gas. For submicron particles, the combined effect of electrostatic adsorption and centrifugal force can greatly improve the separation effect. Compared with simple centrifugal separation, the particles adsorbed by electrostatic force on the wall of the collecting electrode 71 are difficult to be re-entrained by the airflow, significantly reducing the "re-entry phenomenon". The separated flue gas will carry some O3 and NO2 due to ionization. Since the flue gas temperature is around 200℃ to 350℃, O3 will decompose rapidly and cannot exist stably, so it will not affect the CO concentration monitoring. After the flue gas enters the channel body 81, it will come into contact with the activated carbon layer 82. At this time, NO2 will react and become NO and N2, which have no effect on CO monitoring. When the flue gas passes through the activated carbon layer 82, the flow rate will decrease significantly, and the diffusion section 812 will make the flue gas evenly distributed, increasing the contact area and contact uniformity with the working electrode 4, thereby ensuring the accuracy of the detection results.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. A coupling cleaning structure for an electrode-type airflow sensor, comprising a sensor housing (1), a working chamber (2), a circuit board (3), and a working electrode (4); characterized in that: It also includes a barrier cavity (5), a duct assembly (6), an adsorption assembly (7), and a detection channel (8); the barrier cavity (5) is located inside the sensor housing (1); the duct assembly (6) is located inside the barrier cavity (5), and the flue gas enters the duct assembly (6) and undergoes a swirling upward motion; the adsorption assembly (7) is connected to the duct assembly (6), and after the flue gas enters, the adsorption assembly (7) is energized to form an electric field in the duct assembly (6), causing the particulate matter in the flue gas to be subjected to an electric field force in the same direction as the centrifugal force of the swirling flow; the detection channel (8) is connected to the duct assembly (6). The detection channel (8) connects the barrier cavity (5) and the working cavity (2); the air duct assembly (6) includes a spiral air cavity (61), an air inlet channel (62), a spiral plate (63), and a collection groove (64). The spiral air cavity (61) is opened inside the barrier cavity (5). The air inlet channel (62) is connected between the spiral air cavity (61) and the outer wall of the barrier cavity (5), and is tangentially connected to the spiral air cavity (61). The spiral plate (63) is arranged in a spiral array inside the spiral air cavity (61). The collection groove (64) is arranged in the spiral air cavity (61). The bottom of the spiral air chamber (61) has an Archimedean spiral structure in cross-section, and the size of the spiral plate (63) decreases sequentially along the air inlet direction and spirals upward; the adsorption assembly (7) includes a collecting electrode (71), a central electrode (72), a power module (73), and a DC boost module (74). The collecting electrode (71) is connected to the inner wall of the spiral air chamber (61), the central electrode (72) is located at the center of the spiral air chamber (61), the power module (73) is mounted on the circuit board (3), and the DC boost module (74) is mounted on the bottom of the spiral air chamber (61). The circuit board (3) is electrically connected to the power module (73) and the center electrode (72); the collecting electrode (71) is made of stainless steel and is grounded; the center electrode (72) includes an insulating post (721) and a discharge tungsten wire (722), the insulating post (721) is installed at the center of the spiral air cavity (61), the discharge tungsten wire (722) is installed inside the insulating post (721), and the part extending out of the insulating post (721) has a sharp shape and is arranged in a multi-layer circumferential array; the spiral plate (63) and the detection channel (8) are both made of insulating material.

2. The electrode-type airflow sensor coupling cleaning structure according to claim 1, characterized in that: The cross-sectional area of ​​the air inlet channel (62) gradually decreases along the air inlet direction, and a coarse filter screen (621) is provided at the connection position between the air inlet channel (62) and the outer wall of the barrier cavity (5).

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