Coupling cleaning structure of electrode type airflow sensor

Abstract

The invention 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 the blocking cavity; the adsorption assembly is connected with the air duct assembly; the detection channel is connected with the air duct assembly; smoke entering the sensor is subjected to rotational flow, an electric field is used for enabling particulate matter to carry negative charges during rotational flow, the particulate matter is subjected to electrostatic force in the same direction as centrifugal force, it is guaranteed that submicron-level particulate matter can be effectively separated, meanwhile, a Faraday cage can be formed under the grounding effect of a collecting electrode, and therefore the particulate matter can be effectively separated. The influence of an electric field on a working electrode is shielded, and the high temperature of the flue gas is matched with an activated carbon layer to eliminate NO2 which can influence the detection precision in the flue gas, so that the detection precision is ensured; the problems that micron-order and submicron-order particulate matters are difficult to separate in a mechanical mode and normal detection of a sensor is affected when the particulate matters are separated by an alternating electric field are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas detection, in particular to an electrode type airflow sensor coupling cleaning structure. BACKGROUND

[0002] The electrode type airflow sensor is a sensor for detecting the concentration of a gas by generating an electric current signal through the oxidation-reduction reaction of the gas on the surface of an electrode; due to the increasingly serious air pollution, the electrode type airflow sensor is currently mainly used in chemical plants or flues to detect the gas to be monitored, and only when the content of the components in the gas meets the standard can the gas be discharged into the atmosphere.

[0003] When the electrode type airflow sensor is used for flue gas emission monitoring, due to the presence of particulate matter with a small particle size in the flue gas, when the flue gas passes through the electrode surface of the electrode type airflow sensor, part of the particulate matter will adhere to the surface, resulting in a significant decrease in the detection accuracy of the sensor, and a filter screen type structure cannot be used on the airflow sensor to prevent the entry of particulate matter, and the filter screen capable of capturing micrometer-level particulate matter has a large air resistance, and such a filter screen will quickly saturate and be blocked when it comes into contact with high-concentration particulate matter, and it is difficult to clean and needs to be replaced frequently. The prior art has proposed a good solution to this problem, such as the gas flow sensor and gas flow detection method disclosed in patent CN117490785A, in which a self-cleaning chip and an auxiliary flow channel are provided, and the electrodes on the self-cleaning chip can generate an alternating electric field, which can make the particulate matter in the gas enter the auxiliary flow channel, thereby avoiding the adhesion of small particulate matter on the electrodes of the detection chip.

[0004] Although the prior art has solved the problem of easy adhesion of small particulate matter in flue gas on the surface of the electrodes of the detection chip, it still has the following problems: when the alternating electric field is used to drive the movement of the particles, the driving force on the particles is proportional to the charge quantity and the electric field strength, and for particulate matter smaller than 1 μm in flue gas, the charge quantity is low, and a larger electric field strength is required to move it, and a large electric field strength and an alternating electric field frequency close to the working frequency will interfere with the detection electrode, causing fluctuations in the sensor output signal and affecting the accurate monitoring of the gas concentration, and for particulate matter larger than 10 μm in flue gas, it will drift irregularly under the action of inertia without being controlled by the electric field, and when the large particles are not discharged but hit the surface of the electrode under the driving force of the electric field, it will also cause a decrease in the detection accuracy, and for CO concentration detection, the high-voltage electric field will ionize the gas to produce O3 and NO2 which will affect the CO concentration detection, resulting in a further decrease in the detection accuracy.

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

[0006] The application provides an electrode type airflow sensor coupling cleaning structure, which solves the problem that micrometer and submicron particles are difficult to separate mechanically and that the alternating electric field separating the particles affects normal detection of the sensor, by setting a spiral wind cavity with an Archimedes spiral structure, smoke entering the spiral wind cavity spirally flows and the flow rate gradually increases, so that the particles are subjected to centrifugal force, and a central electrode at the center of the spiral wind cavity can generate a corona to make the particles carry negative charges, and the inner wall of the spiral wind cavity is a collecting electrode grounded, at this time, the particles will be subjected to electrostatic force in the same direction as the centrifugal force, ensuring that submicron particles can be effectively separated, and the collecting electrode will form a Faraday cage under the action of grounding, shielding the influence of the electric field on the working electrode, and because of the high temperature condition of the smoke itself, O3 and NO2 generated by ionization and NO2 in the original smoke can 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 precision.

[0007] To achieve the above object, the application provides the following technical scheme.

[0008] An electrode type airflow sensor coupling cleaning structure comprises a sensor shell, a working cavity, a circuit board and a working electrode, further comprises a barrier cavity, an air duct assembly, an adsorption assembly and a detection channel, the barrier cavity is arranged in the sensor shell, the air duct assembly is arranged in the barrier cavity, smoke enters the air duct assembly and performs cyclone upward motion, the adsorption assembly is connected with the air duct assembly, and the smoke enters the adsorption assembly to form an electric field in the air duct assembly and make the particles in the smoke subjected to electric field force in the same direction as the cyclone centrifugal force, and the detection channel is connected with the air duct assembly and communicates the barrier cavity with the working cavity.

[0009] Preferably, the air duct assembly comprises a spiral wind cavity, an air inlet channel, a spiral plate and a collection groove, the spiral wind cavity is arranged in the barrier cavity, the air inlet channel is connected between the spiral wind cavity and the outer wall of the barrier cavity and is tangentially connected with the spiral wind cavity, the spiral plate is spirally arranged in the spiral wind cavity, and the collection groove is arranged at the bottom of the spiral wind cavity.

[0010] In the above scheme, the smoke can perform cyclone motion after entering the spiral wind cavity, and the spiral plate can strengthen the cyclone and assist the smoke to rise, in the process, the particles subjected to centrifugal force and gravity will move to the inner wall of the spiral wind cavity and fall into the collection groove under the action of gravity, so as to complete separation from the smoke.

[0011] Preferably, the cross section of the spiral wind cavity is an Archimedes spiral structure, and the size of the spiral plate gradually decreases along the air inlet direction and spirally rises.

[0012] In the above scheme, the Archimedes spiral structure can gradually increase the flue gas flow rate and enhance the cyclone 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 is a high-temperature gas and flows upward. The spiral plate can cooperate with the flue gas flow direction to further increase the flue gas flow rate, thereby improving the separation effect.

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

[0014] In the above scheme, the air inlet channel has a large opening, which can ensure easy entry of flue gas. After entering, the flow rate will gradually increase due to the reduced flow area. The coarse filter screen can screen out large particulate matter. Compared with micron-sized particulate matter, large particulate matter is easier to clean. The coarse filter screen can be arranged in a detachable structure for easy cleaning and replacement. This reduces the content of large particulate matter in the flue gas entering the spiral wind cavity, thereby reducing the accumulation of particulate matter in the spiral wind cavity after each use and reducing the frequency of disassembly and cleaning of the spiral wind cavity.

[0015] Preferably, the adsorption assembly includes a collection electrode, a center electrode, a power supply module, and a DC voltage booster module. The collection electrode is connected to the inner wall of the spiral wind cavity. The center electrode is arranged at the center position of the spiral wind cavity. The power supply module is installed on a circuit board. The DC voltage booster module is installed on the circuit board and electrically connected to the power supply module and the center electrode.

[0016] In the above scheme, when a high enough negative voltage is applied to the center electrode, the surrounding air molecules will ionize to produce free electrons and negative ions. These electrons and negative ions will attach to the particulate matter, making it negatively charged. The collection electrode is grounded (or a positive high voltage is applied) to make the charged particulate matter subject to Coulomb force (electrostatic force), which firmly adsorbs the particulate matter on the inner wall of the collection electrode. The adsorption effect generated by the electrostatic force can effectively prevent large particulate matter from bouncing off the wall and re-entering the working electrode position with the gas. For sub-micron-sized particulate matter, the combination of electrostatic adsorption force and centrifugal force can greatly improve the separation effect. Compared with simple centrifugal separation, the particulate matter adsorbed on the collection electrode wall by electrostatic force is difficult to be re-voluted by the gas flow, significantly reducing the "re-entry phenomenon". In addition, two separation mechanisms are realized in the same cavity, which can reduce the volume and improve the integration of the sensor.

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

[0018] In the scheme, the ground setting of the collecting electrode can produce adsorption effect on the negatively charged particles, and the cavity formed by the collecting electrode is also set to be grounded, so that a Faraday cage is formed to limit the high-voltage electric field in the cavity, and the detection channel is connected with the collecting electrode, so that the detection channel is also grounded, and there is a certain distance between the detection channel and the working electrode, so that the electric field in the detection channel will be exponentially attenuated, and the normal detection of the working electrode will not be affected.

[0019] Preferably, the central electrode comprises an insulating column and a discharge tungsten wire; the insulating column is installed at the center of the spiral wind cavity; the discharge tungsten wire is installed in the insulating column and protrudes from the insulating column in a sharp structure 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 scheme, the protruding part of the discharge tungsten wire is in a sharp structure, has low corona voltage and stable discharge, can ensure the generation of corona, thereby effectively generating free electrons, and the free electrons are attached to the particles, and the multi-layer circumferential array can cover a wide range of electric field, so that the particles can be uniformly and continuously charged, the insulating column is made of insulating material, which can prevent high-voltage short circuit and breakdown, and the insulation between the central electrode and the collecting electrode can prevent short circuit, thereby ensuring the normal operation of the whole system.

[0021] Preferably, the detection channel comprises a channel body and an activated carbon layer; the channel body is connected between the working cavity and the spiral wind cavity; and the activated carbon layer is arranged in the channel body.

[0022] In the scheme, the gas after the electrostatic adsorption and spiral separation will enter the detection channel, the gas will be adsorbed by the activated carbon layer for the last time, and the flow rate of the flue gas is slowed down, so that the flue gas reaching the working electrode can fully contact the working electrode, thereby ensuring the detection accuracy, and part of O3 and NO2 will be generated in the ionization process, but the temperature of the flue gas is relatively high, and O3 will quickly decompose and cannot exist stably when the temperature is greater than 100 DEG C, so it will not affect the CO concentration monitoring, and NO2 will react with the activated carbon layer under high temperature conditions to become NO and N2 which have no effect on CO monitoring.

[0023] Preferably, the channel body comprises a bending section and a diffusion section; the bending section is connected with the spiral wind cavity; and the diffusion section is connected between the bending section and the working cavity.

[0024] In the scheme, the bending section can strengthen the electric field shielding effect, the diffusion section can slow down the flow rate of the flue gas and make the flue gas uniformly distributed, thereby increasing the contact area and uniformity of the flue gas with the working electrode.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1、Compared with the existing electrode type gas flow sensor, the application is forced to accelerate the cyclone after the flue gas enters through the spiral wind cavity and the spiral plate of the Archimedes spiral structure, thereby enhancing the centrifugal force on the particulate matter in the flue gas and improving the separation effect of the particulate matter and the flue gas; a collection electrode is arranged on the inner wall of the spiral wind cavity, and a center electrode is arranged at the center of the spiral wind cavity; a high negative voltage is applied to the center electrode to generate a corona, so that the particulate matter in the flue gas can be charged negatively, and the negatively charged particulate matter can be attracted by the collection electrode, thereby further improving the separation effect; under the combined action of the electrostatic adsorption force and the centrifugal force, it is difficult for large particulate matter to be re-coiled or bounced by the airflow after being adsorbed on the collection electrode wall by the electrostatic force, thereby significantly reducing the "re-entry phenomenon", and the separation effect of submicron particulate matter is greatly improved, so that the flue gas reaching the working electrode does not carry particulate matter, and the particulate matter adhering to the working electrode is avoided to cause the detection precision to decrease.

[0027] 2、The application can form a Faraday cage by grounding the collection electrode, so as to limit the high-voltage electric field in this area; the "exit" of the entire Faraday cage is a detection channel, and there is a certain distance between the detection channel and the working electrode; and the bending section of the detection channel can strengthen the electric field shielding effect, so that the electric field in the detection channel will present exponential decay, so as to ensure that the normal detection of the working electrode is not affected, thereby ensuring the accuracy of the CO concentration detection of the working electrode.

[0028] 3、The application can perform the last adsorption of the residual particulate matter in the flue gas by arranging the activated carbon layer in the channel body, so as to ensure that the flue gas is cleaner, and the activated carbon layer can also slow down the flow rate of the flue gas, so as to ensure that the flue gas reaching the working electrode position can fully contact the working electrode, thereby ensuring the detection precision; under the condition of high temperature of the flue gas itself, O3 will decompose quickly, and the activated carbon can catalyze the decomposition of O3; the flue gas flowing out after the bending section will not contain O3 any more; and NO2 will react to NO and N2 which have no influence on the CO detection by contacting the activated carbon layer under the condition of high temperature, and the process can also remove the original NO2 in the flue gas, thereby further improving the accuracy of the CO concentration detection. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 It is the overall structure diagram of the present application.

[0031] Figure 2 The internal structure of the present application is shown in the figure;

[0032] Figure 3 The cross-sectional view of the air duct assembly of the present application is shown in the figure;

[0033] Figure 4 The cross-sectional view of the central electrode of the present application is shown in the figure;

[0034] Figure 5 The Figure 4 The structure at point A in the figure is enlarged;

[0035] Figure 6 The exploded view of the present application is shown in the figure;

[0036] Figure 7 The structure of the detection channel of the present application is shown in the figure;

[0037] Figure 8 The smoke flow direction when the present application is used is shown in the figure;

[0038] In the figure: 1, sensor shell; 2, working cavity; 3, circuit board; 4, working electrode; 5, barrier cavity; 6, air duct assembly; 61, spiral air cavity; 62, air inlet channel; 621, coarse filter screen; 63, spiral plate; 64, collection groove; 7, adsorption assembly; 71, collection electrode; 72, central electrode; 721, insulating column; 722, discharge tungsten wire; 73, power module; 74, DC voltage booster module; 8, detection channel; 81, channel body; 811, bending section; 812, diffusion section; 82, activated carbon layer. DETAILED DESCRIPTION

[0039] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings in the specification and specific embodiments.

[0040] Please refer to Figures 1 to 8 The present application provides an electrode type air flow sensor coupling cleaning structure, and the technical solutions are as follows:

[0041] As a specific embodiment of the present application, refer to Figure 1 and Figure 2The utility model provides a kind of electrode type airflow sensor coupling cleaning structure;Including sensor shell 1, working cavity 2, circuit board 3 and working electrode 4;It further includes barrier cavity 5, air duct component 6, adsorption component 7 and detection channel 8;The barrier cavity 5 is opened in sensor shell 1;The air duct component 6 is arranged in barrier cavity 5, and flue gas enters air duct component 6 and carries out cyclone rising motion;The adsorption component 7 is connected with air duct component 6, and flue gas enters and adsorption component 7 is powered in air duct component 6 to form electric field and makes that particulate matter in flue gas receives electric field force in same direction with cyclone centrifugal force;The detection channel 8 is connected with air duct component 6, and detection channel 8 communicates barrier cavity 5 with working cavity 2.

[0042] As a specific embodiment of the present application, refer to Figure 2 And Figure 3 The air duct component 6 includes spiral wind cavity 61, air inlet channel 62, spiral plate 63 and collection groove 64;The spiral wind cavity 61 is opened in barrier cavity 5;The air inlet channel 62 is connected between spiral wind cavity 61 and the outer wall of barrier cavity 5, and is tangentially connected between spiral wind cavity 61;The spiral plate 63 is spirally arranged in spiral wind cavity 61;The collection groove 64 is arranged at the bottom of spiral wind cavity 61.By flue gas entering spiral wind cavity 61, cyclone motion can be carried out, and spiral plate 63 can strengthen cyclone and assist flue gas to rise, and particulate matter will move to the inner wall of spiral wind cavity 61 under the action of centrifugal force and gravity, and will fall to collection groove 64 under the action of gravity, thereby completing separation from flue gas;Spiral wind cavity 61 can be arranged in a detachable structure, and after being used for a period of time, spiral wind cavity 61 is disassembled, and particulate matter in collection groove 64 can be removed, thereby reducing replacement cost.

[0043] As a specific embodiment of the present application, refer to Figure 2 And Figure 3 The cross section of the spiral wind cavity 61 is an Archimedes spiral structure;The size of the spiral plate 63 gradually decreases along the air inlet direction and spirally rises.By Archimedes spiral structure, flue gas flow rate can be gradually increased, and cyclone effect of flue gas can be enhanced, so that centrifugal force on particulate matter gradually increases, thereby effectively separating particulate matter from flue gas;Flue gas itself is a high-temperature gas, and rises in flow, and spiral plate 63 can cooperate with the flow direction of flue gas, further increasing the flow rate of flue gas, thereby improving separation effect.

[0044] As a specific embodiment of the present application, refer to Figure 2 And Figure 3The air inlet channel 62 is gradually reduced in cross-sectional area along the air inlet direction, and a coarse filter screen 621 is arranged at the position where the air inlet channel 62 is connected to the outer wall of the blocking cavity 5. The air inlet channel 62 has a large opening, which can ensure that the flue gas is easy to enter, and after entering, the flow rate will gradually increase under the reduction of the flow area. The coarse filter screen 621 can screen out large particles, which are easier to clean than micron-sized particles. The coarse filter screen 621 can be arranged in a detachable structure for easy cleaning and replacement, so that the content of large particles in the flue gas entering the spiral wind cavity 61 is reduced, thereby reducing the accumulation amount of particles in the spiral wind cavity 61 after each use, and reducing the frequency of disassembly and cleaning of the spiral wind cavity 61.

[0045] As a specific embodiment of the present application, reference is made to Figure 3 , Figure 4 and Figure 6The adsorption assembly 7 includes a collection electrode 71, a center electrode 72, a power module 73 and a direct current boosting module 74; the collection electrode 71 is connected with the inner wall of the spiral wind cavity 61; the center electrode 72 is arranged at the center position of the spiral wind cavity 61; the power module 73 is installed on the circuit board 3; the direct current boosting module 74 is installed on the circuit board 3 and electrically connected with the power module 73 and the center electrode 72. When a high enough negative voltage is applied to the center electrode 72, the surrounding air molecules are ionized to generate free electrons and negative ions, and these electrons and negative ions will adhere to the particulate matter to make it carry a negative charge, and the collection electrode 71 can make the charged particulate matter be subjected to the coulomb force (electrostatic force) by grounding (or applying a positive high voltage), so that the particulate matter is firmly adsorbed on the inner wall of the collection electrode 71. The adsorption effect generated by the electrostatic force can effectively avoid the rebound of the large particulate matter hitting the wall, so that the particulate matter reaches the working electrode 4 position again with the gas. For submicron particles, under the joint action of electrostatic adsorption force and centrifugal force, the separation effect can be greatly improved, and compared with simple centrifugal separation, the particulate matter adsorbed on the wall of the collection electrode 71 by the electrostatic force is difficult to be rolled up again by the gas flow, thereby significantly reducing the "reentry phenomenon". In addition, two separation mechanisms are realized in the same cavity, which can reduce the volume sensor and improve the integration. The power module 73 (AC / DC module) can convert alternating current into direct current, and the direct current boosting module 74 can boost the original low voltage to above 3kV, so that the center electrode 72 can generate corona. The collection electrode 71 is made of stainless steel and is grounded. The ground setting of the collection electrode 71 can produce an adsorption effect on the negatively charged particulate matter. Since the cavity formed by the collection electrode 71 is grounded, a Faraday cage can be formed to limit the high-voltage electric field in this area. In combination with the detection channel 8 connected with the collection electrode 71, the detection channel 8 is also grounded, and there is a certain distance between the detection channel 8 and the working electrode 4, so that the electric field in the detection channel 8 will present exponential decay, which can ensure that the normal detection of the working electrode 4 will not be affected. The adsorption assembly 7 can be switched by various ways. The first way is to manually control the opening through the Internet of Things when the specific exhaust gas needs to be detected. The second way is that the current generated by the corona of the center electrode 72 is only microamperes, so even if it remains in the open state, the power consumption is also very low, which can ensure that the particulate matter can be subjected to the electrostatic adsorption force at any time. The third way is to set an additional electrode by an external sensor to detect CO. Only when an abnormal change of concentration is detected, the power supply is automatically turned on to apply a negative voltage to the center electrode 72.

[0046] As a specific embodiment of the present application, reference is made to Figure 4 and Figure 5The center electrode 72 comprises an insulating column 721 and a discharge tungsten wire 722; the insulating column 721 is installed at the center position of the spiral wind cavity 61; the discharge tungsten wire 722 is installed in the insulating column 721 and the protruding part of the insulating column 721 is in a sharp structure and arranged in a multi-layer circumferential array; the spiral plate 63 and the detection channel 8 are both made of insulating material. The protruding part of the discharge tungsten wire 722 is in a sharp structure, has low corona voltage, stable discharge, can ensure the generation of corona, thereby effectively generating free electrons, allowing the free electrons to adhere to the particulate matter, and the multi-layer circumferential array can make the electric field cover a wide range, which can uniformly and continuously charge the particulate matter; the insulating column 721 is made of insulating material, which can prevent the generation of high-voltage short circuit and breakdown phenomenon, and the insulation between the center electrode 72 and the collecting electrode 71 can avoid short circuit, thereby ensuring the normal operation of the whole system; here, the insulating column 721, the spiral plate 63 and the detection channel 8 can all be made of ceramic material, which has good insulation capacity and can withstand high temperature, and can ensure the service life when used in high-temperature flue gas and other scenes.

[0047] As a specific embodiment of the present application, reference is made 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 cavity 2 and the spiral wind cavity 61; and the activated carbon layer 82 is arranged in the channel body 81. After electrostatic adsorption and spiral separation, the gas enters the detection channel 8, and the gas passes through the activated carbon layer 82 to adsorb the remaining particulate matters for the last time, slow down the flow rate of the flue gas, ensure that the flue gas reaching the working electrode 4 can fully contact the working electrode 4, thereby ensuring the detection accuracy. During the ionization process, part of O3 and NO2 are generated. Since the flue gas is originally at a high temperature (about 200-350°C), O3 will quickly decompose and cannot exist stably when the temperature is greater than 100°C, so it will not affect the CO concentration monitoring. NO2 will react with the activated carbon layer 82 under high temperature conditions to become NO and N2, which have no effect on CO monitoring. When the temperature is greater than 100°C, the main reaction product is NO when the temperature is 100-300°C, and the reaction product is NO and N2 when the temperature is greater than 300°C. This process can also effectively eliminate the influence of NO2 originally existing in the flue gas on CO concentration monitoring (when using the redox reaction of the electrode to monitor the CO concentration, the change between the current value and the standard value is mainly used to obtain the result. If NO2 exists, it will react with the working electrode 4 to produce a negative current, thereby offsetting part of the positive current signal generated by CO, thereby 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 with the spiral wind cavity 61; and the diffusion section 812 is connected between the bending section 811 and the working cavity 2. The bending section 811 can strengthen the electric field shielding effect, so that the electric field can be fully attenuated. The diffusion section 812 can slow down the flow rate of the flue gas and make the flue gas uniformly distributed, thereby increasing the contact area and uniformity with the working electrode 4, thereby ensuring the accuracy of the detection result.

[0048] Workflow: After the flue gas enters the spiral wind cavity 61, it is accelerated to rotate, so that the particulate matters are subjected to centrifugal force, and the central electrode 72 generates corona, so that the particulate matters carry negative charges. At this time, the particulate matters will be subjected to electrostatic adsorption force in the same direction as the centrifugal force, and move towards the collecting electrode 71. After the flue gas separates the particulate matters, it enters the detection channel 8, eliminates O3 and NO2 affecting the detection result, slows down the flow rate, and finally enters the working cavity 2 to contact the working electrode 4 for detection.

[0049] The flue gas passes through the coarse filter screen 621 to be preliminarily screened to remove large particles, at this time, the particles will enter the spiral wind cavity 61 from the air inlet channel 62, since the flow area of the air inlet channel 62 gradually decreases along the air inlet direction, the gas will be preliminarily accelerated, when the gas enters the spiral wind cavity 61, under the Archimedes spiral structure of the spiral wind cavity 61 and the flow guiding effect of the spiral plate 63, the flue gas will be forced to rotate and the flow rate will gradually increase; in the process of flue gas rotation, the power module 73 converts alternating current into direct current, and then the direct current boosting module 74 boosts the voltage to above 3kV, and applies a negative voltage to the central electrode 72, the corona generated by the discharge tungsten wire 722 ionizes the surrounding air to generate free electrons and negative ions, these electrons and negative ions will adhere to the particles to make them carry negative electricity, and the collecting electrode 71 is grounded, so that the charged particles are subjected to the coulomb force, thereby being firmly adsorbed on the inner wall of the collecting electrode 71, effectively avoiding the rebound of large particles hitting the wall to cause the particles to reach the working electrode 4 position again with the gas, and for submicron particles, under the joint action of electrostatic adsorption force and centrifugal force, the separation effect can be greatly improved, and compared with simple centrifugal separation, the particles adsorbed on the wall of the collecting electrode 71 by the electrostatic force are difficult to be rolled up again by the gas flow, thereby significantly reducing the "reentry phenomenon", and the separated flue gas will carry part of O3 and NO2 due to ionization, since the temperature of the flue gas itself is about 200-350℃, O3 will quickly decompose and cannot exist stably, and will not affect the CO concentration monitoring, when the flue gas enters the channel body 81, it will contact the activated carbon layer 82, at this time, NO2 will react to 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 be significantly reduced, and the diffusion section 812 will make the flue gas uniformly distributed, thereby expanding the contact area and uniformity with the working electrode 4, so as to ensure the accuracy of the detection result.

[0050] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application, the scope of protection of the present application is 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) and causes 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 duct assembly (6), and the detection channel (8) connects the barrier cavity (5) and the working chamber (2).

2. The electrode-type airflow sensor coupling cleaning structure according to claim 1, characterized in that: 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 in 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 in the spiral air cavity (61); the collection groove (64) is located at the bottom of the spiral air cavity (61).

3. The electrode-type airflow sensor coupling cleaning structure according to claim 2, characterized in that: The cross-section of the spiral air cavity (61) is an Archimedes spiral structure; the size of the spiral plate (63) decreases sequentially along the air inlet direction and spirals upward.

4. The electrode-type airflow sensor coupling cleaning structure according to claim 2, 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).

5. The electrode-type airflow sensor coupling cleaning structure according to claim 2, characterized in that: The 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 chamber (61); the central electrode (72) is located at the center of the spiral air chamber (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 is electrically connected to the power supply module (73) and the central electrode (72).

6. The electrode-type airflow sensor coupling cleaning structure according to claim 5, characterized in that: The collecting electrode (71) is made of stainless steel and is grounded.

7. The electrode-type airflow sensor coupling cleaning structure according to claim 5, characterized in that: The central electrode (72) includes an insulating column (721) and a discharge tungsten wire (722); the insulating column (721) is installed at the center of the spiral air cavity (61); the discharge tungsten wire (722) is installed inside the insulating column (721), and the part extending out of the insulating column (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.

8. The electrode-type airflow sensor coupling cleaning structure according to claim 2, characterized in that: The 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).

9. The electrode-type airflow sensor coupling cleaning structure according to claim 8, characterized in that: The channel body (81) includes a bent section (811) and a diffuser section (812); the bent section (811) is connected to the spiral air chamber (61); the diffuser section (812) is connected between the bent section (811) and the working chamber (2).

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