Continuous monitoring device and monitoring method for concentration of VOCs (Volatile Organic Compounds) in air

Abstract

The invention relates to the technical field of FID detectors, in particular to a continuous monitoring device and monitoring method for the concentration of VOCs in air, and the continuous monitoring device for the concentration of VOCs in air comprises a detector body, an ignition assembly and a one-way transmission mechanism; a gas outlet is formed in the detector body, a collector is arranged in the detector body, and the ignition assembly comprises an insulating ring and a conductive part; a plurality of heating wires are uniformly distributed in the circumferential direction of the insulating ring; the conductive part is used for electrifying the heating wire, the conductive part is provided with a first end and a second end which are distributed in the horizontal direction, the first end is slidably arranged on the detector body in the horizontal direction, and the second end is rotationally connected with the insulating ring; the one-way transmission mechanism can drive the insulation part to rotate around the axis of the insulation part by a set angle, so that the conductive part can be conductively connected with the next adjacent heating wire, and the service life can be prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of FID detectors, in particular to a continuous monitoring device and method for air VOCs concentration. BACKGROUND

[0002] VOCs belong to volatile organic compounds, and high concentration of VOCs gas can cause serious harm to human health, so monitoring the concentration of air VOCs is very important. In the prior art, a hydrogen flame ionization detector (FID) is usually used for monitoring. The hydrogen flame ionization detector is the most commonly used detector in gas chromatographs, and its working principle is to burn carbon-containing organic matter in a hydrogen flame and detect the ions generated by combustion.

[0003] The patent document with publication number CN221124414U discloses a portable FID detector that avoids extinguishing, wherein a mounting block is mounted on the side wall of the detector, the mounting block is threadedly connected with the detector, and an ignition wire is mounted in the mounting block. The ignition wire is used for ignition. Since the ignition wire is in a high-temperature and oxygen-rich environment for a long time, the ignition wire is prone to oxidation and aging, which leads to failure of the ignition wire and affects the service life of the FID detector. SUMMARY

[0004] Therefore, it is necessary to provide a continuous monitoring device and method for air VOCs concentration to solve the technical problem that the ignition wire in the FID detector is prone to failure and affects the service life.

[0005] The above-mentioned purpose is achieved by the following technical solutions: The application discloses a continuous monitoring device for air VOCs concentration, which comprises a detector body, an ignition assembly and a one-way transmission mechanism; the detector body is provided with a gas outlet for burning and discharging sample gas containing VOCs; the inside of the detector body is provided with a collecting electrode in a cylindrical shape, and the axis of the collecting electrode extends in the up-down direction; the ignition assembly is located in the gas outlet and above the collecting electrode, and the ignition assembly comprises an insulating ring and a conductive piece; the axis of the insulating ring extends in the up-down direction, and a plurality of heating wires are uniformly distributed in the circumferential direction of the insulating ring; the conductive piece is used for electrifying the heating wires, and the electrified heating wires can ignite the sample gas containing VOCs; the conductive piece has a first end and a second end which are distributed in the horizontal direction, the first end is arranged on the detector body in the horizontal direction, and the second end is rotationally connected with the insulating ring; when the sample gas containing VOCs is ignited and flows through the conductive piece, the conductive piece can pull the insulating ring to move in the horizontal direction, so that the insulating ring moves from a first limit position to a second limit position, at the first limit position, the axis of the insulating ring is located on one side of the axis of the collecting electrode, and at the second limit position, the axis of the insulating ring coincides with the axis of the collecting electrode; the one-way transmission mechanism is arranged between the insulating ring and the inner wall of the gas outlet, and when the insulating ring moves from the first limit position to the second limit position, the one-way transmission mechanism can drive the insulating ring to rotate around the axis thereof by a set angle, so that the conductive piece can be in conductive connection with the adjacent next heating wire.

[0006] Further, a plurality of conductive parts are uniformly distributed in the circumferential direction of the insulating ring, the heating wire is located between adjacent two conductive parts, and the two ends of the heating wire are respectively in conductive connection with the two conductive parts; the second end of the conductive piece is provided with two conductive sheets which are in the shape of inverted U and are clamped on the insulating ring; the interval between adjacent two conductive sheets is equal to the interval between adjacent two conductive parts, and the two conductive sheets can be in conductive contact with the adjacent two conductive parts at the same time, so as to realize electrification of the heating wire.

[0007] Further, the conductive piece further comprises an insulating plate which extends in the vertical direction, and the two conductive sheets are fixedly arranged on the same side surface of the insulating plate; the insulating plate is provided with a guide plate which is arranged in an inclined manner relative to the up-down direction and can push the guide plate to move in the horizontal direction after the sample gas containing VOCs is ignited, so as to pull the insulating ring to move in the horizontal direction through the conductive sheet.

[0008] Further, the upper end of the detector body is detachably connected with an end cover, two guide holes are arranged on the end cover, the first end of the conductive part is provided with two conductive rods, the two conductive rods are fixedly arranged on the side of the insulating plate away from the conductive sheet, the conductive rods are in one-to-one correspondence with the guide holes and are in sliding connection, a first reset spring is sleeved on the conductive rod, and the first reset spring has a tendency to make the insulating ring in the first limit position.

[0009] Further, the one-way transmission mechanism comprises a rack and a gear, the rack extends in the horizontal direction, the gear is coaxially arranged on the insulating ring, the rack is arranged on the inner wall of the end cover through a second reset spring, and the second reset spring has a tendency to make the rack close to the gear; when the insulating ring moves from the first limit position to the second limit position, the gear and the rack can be engaged, so that the insulating ring can rotate around its own axis; when the insulating ring moves from the second limit position to the first limit position, the gear and the rack can be in sliding fit in the horizontal direction, so that the insulating ring can slide along the horizontal direction relative to the rack.

[0010] Further, the cleaning assembly comprises a cleaning ring, the cleaning ring is coaxially arranged with the collecting electrode and is supported on the upper end surface of the collecting electrode, the bottom of the cleaning ring is provided with a plurality of support rods which are uniformly distributed around the circumference of the cleaning ring, the support rods extend in the up-down direction and are located in the collecting electrode, and the outer circumferential surface of the support rod is provided with a scraping ring, the scraping ring is coaxial with the collecting electrode and is in close contact with the inner wall of the collecting electrode, and when the cleaning ring slides in the up-down direction, the scraping ring can clean the inner wall of the collecting electrode.

[0011] Further, the bottom of the insulating plate is provided with a blocking plate extending in the horizontal direction, when the insulating ring is in the first limit position, the blocking plate is in abutting fit with the cleaning ring in the up-down direction, so as to prevent the cleaning ring from moving upward, and when the insulating ring moves to the second limit position, the cleaning ring can move upward.

[0012] Further, the detector body is also provided with a containing groove, and the containing groove is located on one side of the collecting electrode; a telescopic bag is arranged in the containing groove, the lower end of the telescopic bag is connected with the bottom of the containing groove, and the upper end of the telescopic bag is connected with the bottom of the cleaning ring; the telescopic bag can extend and contract in the up-down direction, so as to drive the cleaning ring to move in the up-down direction.

[0013] Further, the inside of the telescopic bag is filled with a low-boiling-point liquid, and the low-boiling-point liquid can expand and contract with heat, so as to drive the telescopic bag to extend and contract.

[0014] A continuous monitoring method of air VOCs concentration, which adopts the continuous monitoring device of air VOCs concentration, comprises the following steps: S1, sample gas containing VOCs is introduced into the detector body; S2. The heating wire is energized through a conductive component, causing the heating wire to ignite the sample gas containing VOCs; S3. The collecting electrode continuously monitors the ions generated during the combustion of sample gas containing VOCs and generates a micro-current signal; S4. Calculate the concentration of VOCs in the air based on the microcurrent signal.

[0015] The beneficial effects of this invention are: The present invention provides a continuous monitoring device and method for VOCs concentration in the air. First, when a sample gas containing VOCs is ignited and flows through a conductive element, the conductive element can pull an insulating ring to move horizontally, causing the insulating ring to move from a first limit position to a second limit position. When the insulating ring moves from the first limit position to the second limit position, the unidirectional transmission mechanism can drive the insulating ring to rotate around its own axis by a set angle, thereby enabling the conductive element to make a conductive connection with the next adjacent heating wire. In this way, when the sample gas containing VOCs is ignited again, it is achieved by energizing the next heating wire, avoiding damage caused by repeated use of a single heating wire and extending the service life of the continuous monitoring device for VOCs concentration in the air.

[0016] Secondly, by setting up a cleaning component, pollutants adhering to the inner wall of the collecting electrode can be scraped off and carried away by the airflow, thereby preventing pollutants from affecting the monitoring of the collecting electrode and improving the monitoring accuracy of the continuous monitoring device for air VOCs concentration. Attached Figure Description

[0017] Figure 1 A three-dimensional structural schematic diagram of a continuous monitoring device for air VOCs concentration provided in an embodiment of the present invention; Figure 2 A side view schematic diagram of a continuous monitoring device for air VOCs concentration provided in an embodiment of the present invention. Figure 1 ; Figure 3 A side view schematic diagram of a continuous monitoring device for air VOCs concentration provided in an embodiment of the present invention. Figure 2 ; Figure 4 for Figure 3 Sectional view of AA; Figure 5 for Figure 4 Enlarged view of the structure at point C (the insulating ring is in the first extreme position); Figure 6 for Figure 5 Another schematic diagram of the state (the insulating ring is in the second extreme position); Figure 7 for Figure 3 BB section view; Figure 8 The explosion schematic view of the continuous monitoring device for air VOCs concentration provided by an embodiment of the present application; Figure 9 The structure schematic view of the ignition assembly in the continuous monitoring device for air VOCs concentration provided by an embodiment of the present application; Figure 10 The side view schematic view of the ignition assembly in the continuous monitoring device for air VOCs concentration provided by an embodiment of the present application; Figure 11 The structure schematic view of the cleaning assembly in the continuous monitoring device for air VOCs concentration provided by an embodiment of the present application.

[0018] Wherein: 101, base; 1011, hydrogen gas inlet; 1012, oxygen gas inlet; 102, nozzle; 103, nut; 104, gas chromatographic column; 105, collector; 106, insulating sheet; 107, support seat; 108, compression seat; 109, end cover; 110, rack; 1101, second reset spring; 201, heating wire; 202, insulating ring; 203, conductive part; 204, gear; 301, conductive sheet; 302, insulating plate; 3021, blocking plate; 3022, guide plate; 303, conductive rod; 304, first reset spring; 401, cleaning ring; 402, support rod; 403, scraping ring; 404, telescopic bag. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below by embodiments and in conjunction with the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0020] The serial numbers of components in this paper, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any sequence or technical meaning. And the "connection" and "coupling" in the present application, unless otherwise specified, include direct and indirect connection (coupling). In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0021] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0022] As shown in Figures 1 to 11 An embodiment of the present application provides a continuous monitoring device for air VOCs concentration, which comprises a detector body, an ignition assembly and a one-way transmission mechanism.

[0023] The detector body is provided with a gas outlet for burning and discharging sample gas containing VOCs, and the inside of the detector body is provided with a collector 105 in a cylindrical shape, and the axis of the collector 105 extends in the upward and downward direction; the ignition assembly is located in the gas outlet and above the collector 105.

[0024] The ignition assembly comprises an insulating ring 202 and a conductive part; the axis of the insulating ring 202 extends in the upward and downward direction, and a plurality of heating wires 201 are uniformly distributed in the circumferential direction of the insulating ring 202; the conductive part is used to electrify the heating wires 201, and the heating wires 201 can ignite the sample gas containing VOCs after electrification; the conductive part has a first end and a second end distributed in the horizontal direction, the first end is slidingly arranged on the detector body in the horizontal direction, and the second end is rotationally connected with the insulating ring 202; when the sample gas containing VOCs is ignited and flows through the conductive part, the conductive part can pull the insulating ring 202 to move in the horizontal direction, so that the insulating ring 202 moves from the first limit position to the second limit position, at the first limit position, the axis of the insulating ring 202 is located on one side of the axis of the collector 105, and at the second limit position, the axis of the insulating ring 202 coincides with the axis of the collector 105.

[0025] When the insulating ring 202 moves from the first limit position to the second limit position, the one-way transmission mechanism can drive the insulating ring 202 to rotate around its own axis by a set angle, so that the conductive part can be electrically connected with the adjacent next heating wire 201.

[0026] Specifically, the detector body includes a base 101, a support seat 107, and a compression seat 108 connected in sequence from bottom to top by threads, and the collector 105 is arranged inside the support seat 107 and the compression seat 108, and the outside of the collector 105 is provided with an insulating sheet 106, which is located between the end face of the support seat 107 and the end face of the compression seat 108, and the insulating sheet 106 insulates the collector 105 arranged inside the support seat 107 and the compression seat 108.

[0027] The insulating ring 202 is provided with N heating wires, so that the set angle of the rotation of the insulating ring 202 around its own axis is 360° / N. In this embodiment, N is equal to 6. In other embodiments, N can be 4, 5, 7, etc.

[0028] The base 101 is provided with an oxygen inlet 1012 and a hydrogen inlet 1011, and a nozzle 102 is threadedly connected inside the base 101, the oxygen inlet 1012 corresponds to the upper position of the nozzle 102, and the hydrogen inlet 1011 corresponds to the position of the outer periphery of the nozzle 102. The bottom of the base 101 is connected with a nut 103, and the nut 103 is provided with a gas chromatographic column 104, which corresponds to the inside of the nozzle 102, and the gas chromatographic column 104 is used to introduce a carrier gas (nitrogen or helium) and a sample gas containing VOCs. Hydrogen flows through the bottom of the nozzle 102 into the nozzle 102 through the hydrogen inlet 1011 and corresponds to the position of the outer periphery of the gas chromatographic column 104, and finally mixes with the sample gas containing VOCs at the end of the nozzle 102. When the heating wire 201 of the ignition assembly heats to the ignition temperature, the heating wire 201 can ignite the sample gas containing VOCs, and under the combustion-supporting action of oxygen, a flame is generated at the position of the nozzle 102, the sample gas containing VOCs can continue to burn and generate ions in the collector 105, the collector 105 can collect the ions generated in the flame and generate a micro-current signal, and transmit it to the data processing system, so as to calculate the concentration of air VOCs.

[0029] When the sample gas containing VOCs is ignited and flows through the conductive part, the conductive part can pull the insulating ring 202 to move in the horizontal direction, so that the insulating ring 202 moves from the first limit position to the second limit position, and when the insulating ring 202 moves from the first limit position to the second limit position, the one-way transmission mechanism can drive the insulating ring 202 to rotate around its own axis by a set angle, so that the conductive part can be in conductive connection with the next adjacent heating wire 201, so that when the sample gas containing VOCs is ignited again, it is realized by the power supply of the next heating wire 201, avoiding the damage caused by the repeated use of a single heating wire 201, and prolonging the service life of the continuous monitoring device for air VOCs concentration.

[0030] Further, the insulating ring 202 is uniformly distributed with a plurality of conductive parts 203 in the circumferential direction, the heating wire 201 is located between two adjacent conductive parts 203, and the two ends of the heating wire 201 are respectively in conductive connection with two conductive parts 203, the second end of the conductive part is provided with two conductive sheets 301, the two conductive sheets 301 are inverted U-shaped and are arranged on the insulating ring 202, the interval between two adjacent conductive sheets 301 is equal to the interval between two adjacent conductive parts 203, and the two conductive sheets 301 can be in conductive contact with two adjacent conductive parts 203 at the same time, so as to realize the power supply of the heating wire 201.

[0031] In this way, the conductive connection stability of the conductive sheet 301 and the conductive part 203 can be ensured, and the heating effect of the heating wire 201 can be ensured.

[0032] Further, the conductive part further comprises an insulating plate 302, the insulating plate 302 extends in the vertical direction, and the two conductive sheets 301 are fixedly arranged on the same side surface of the insulating plate 302, the insulating plate 302 is provided with a guide plate 3022, the guide plate 3022 is arranged in an inclined manner with respect to the up-down direction, and after the sample gas containing VOCs is ignited, the guide plate 3022 can be pushed to move in the horizontal direction, and then the insulating ring 202 is pulled to move in the horizontal direction through the conductive sheet 301.

[0033] In this way, the thrust generated by the combustion of the sample gas containing VOCs can be utilized to automatically realize the movement of the insulating ring 202 pulled by the conductive part, without manual operation.

[0034] The pressing seat 108 is provided with a avoiding opening for avoiding the insulating plate 302, and the insulating plate 302 can block the dust from entering the inside of the collecting electrode 105.

[0035] Further, the upper end of the detector body is detachably connected with an end cover 109, the end cover 109 is provided with two guide holes, the first end of the conductive part is provided with two conductive rods 303, the two conductive rods 303 are fixedly arranged on the side surface of the insulating plate 302 away from the conductive sheet 301, the conductive rod 303 is in one-to-one correspondence with the guide hole and is in sliding connection, the first reset spring 304 is sleeved on the conductive rod 303, and the first reset spring 304 is located between the inner wall of the end cover 109 and the insulating plate 302, and the first reset spring 304 has a tendency to make the insulating ring 202 in the first limit position.

[0036] Specifically, the end cover 109 is threadedly connected above the pressing seat 108. The conductive rod 303 and the guide hole can guide the conductive part 303 to move in the horizontal direction. The first reset spring 304 is arranged to facilitate the reset of the insulating ring 202.

[0037] Further, the one-way transmission mechanism comprises a rack 110 extending in the horizontal direction and a gear 204 coaxially arranged on the insulation ring 202, the rack 110 is arranged on the inner wall of the end cover 109 through a second reset spring 1101, the second reset spring 1101 has a tendency to make the rack 110 close to the gear 204; when the insulation ring 202 moves from the first limit position to the second limit position, the gear 204 can mesh with the rack 110, so that the insulation ring 202 can rotate around its own axis; when the insulation ring 202 moves from the second limit position to the first limit position, the gear 204 and the rack 110 can be slidingly fitted in the horizontal direction, so that the insulation ring 202 can slide in the horizontal direction relative to the rack 110.

[0038] As shown in Figure 7 The gear 204 is provided with a plurality of first teeth in the circumferential direction, one side of the first teeth is designed as a first inclined surface, and the other side is designed as a curved surface. The rack 110 is provided with second teeth, one side of the second teeth is designed as a second inclined surface, and the other side is designed as a curved surface. When the insulation ring 202 moves from the first limit position to the second limit position, the gear 204 and the rack 110 are normally meshed through the curved surface. When the insulation ring 202 moves from the second limit position to the first limit position, the first inclined surface of the gear 204 and the second inclined surface of the rack 110 are slidingly fitted, so that the insulation ring 202 can slide in the horizontal direction relative to the rack 110.

[0039] This design can ensure that the plurality of heating wires 201 are used in turn, and prolong the service life of the heating wire 201.

[0040] Further, the cleaning assembly comprises a cleaning ring 401 coaxially arranged with the collecting electrode 105 and supported on the upper end surface of the collecting electrode 105, the bottom of the cleaning ring 401 is provided with a plurality of support rods 402 uniformly distributed in the circumferential direction thereof, the support rods 402 extend in the up-down direction and are located in the collecting electrode 105, and the outer circumferential surface of the support rod 402 is provided with a scraping ring 403 coaxial with the collecting electrode 105 and abutting against the inner wall of the collecting electrode 105, when the cleaning ring 401 slides in the up-down direction, the scraping ring 403 can clean the inner wall of the collecting electrode 105.

[0041] By arranging the cleaning assembly, the pollutants adhered to the inner wall of the collecting electrode 105 can be scraped off and carried away by the airflow, so that the pollutants do not affect the monitoring of the collecting electrode 105, and the monitoring accuracy of the continuous monitoring device of the air VOCs concentration is improved.

[0042] Furthermore, the bottom of the insulating plate 302 is provided with a horizontally extending baffle plate 3021. When the insulating ring 202 is in the first extreme position, the baffle plate 3021 and the cleaning ring 401 are in a blocking engagement in the vertical direction, thereby preventing the cleaning ring 401 from moving upward. When the insulating ring 202 moves to the second extreme position, the cleaning ring 401 can move upward. This can prevent the cleaning ring 401 from cleaning the inner wall of the collecting electrode 105 prematurely.

[0043] Furthermore, the detector body is also provided with a receiving groove located on one side of the collecting electrode 105; a telescopic bladder 404 is provided in the receiving groove, the lower end of the telescopic bladder 404 is connected to the bottom of the receiving groove, and the upper end of the telescopic bladder 404 is connected to the bottom of the cleaning ring 401. The telescopic bladder 404 can extend and retract in the vertical direction, thereby driving the cleaning ring 401 to move in the vertical direction. Specifically, the receiving groove is set on the clamping seat 108. The cleaning ring 401 is moved up and down by the telescopic bladder 404, which has a simple structure.

[0044] Furthermore, the interior of the telescopic bladder 404 is filled with a low-boiling-point liquid, which is capable of thermal expansion and contraction, thereby causing the telescopic bladder 404 to expand and contract. The low-boiling-point liquid is ethanol or acetone, etc.

[0045] In this way, after the temperature of the detector body rises due to the combustion of sample gas containing VOCs, the low-boiling-point liquid will expand, thereby automatically causing the expansion and contraction of the telescopic bladder 404. After the temperature of the detector body decreases, the low-boiling-point liquid will contract, thereby automatically causing the expansion and contraction of the telescopic bladder 404, thus automatically cleaning the inner wall of the collecting electrode 105 without manual operation.

[0046] Based on the above embodiments, the usage principle and working process of the embodiments of the present invention are as follows: In the initial state, such as Figure 5 As shown, the insulating ring 202 is in the first extreme position. A carrier gas and a sample gas containing VOCs are introduced into the gas chromatography column 104, allowing the VOCs-containing sample gas to be delivered into the nozzle 102. Hydrogen gas flows through the hydrogen inlet 1011, passes through the bottom of the nozzle 102, and enters the nozzle 102 at a position corresponding to the outer periphery of the gas chromatography column 104. Finally, it mixes with the VOCs-containing sample gas at the end of the nozzle 102. Connected to an external power source via a conductive component, the heating wire 201 of the ignition assembly is heated to its ignition temperature. The heating wire 201 ignites the VOCs-containing sample gas. With the aid of oxygen, a flame is generated at the nozzle 102. The VOCs-containing sample gas continues to burn, generating ions in the collecting electrode 105. The collecting electrode 105 collects the ions generated in the flame and generates a micro-current signal, which is transmitted to the data processing system to calculate the air VOCs concentration.

[0047] Wherein, when the sample gas containing VOCs is ignited and flows through the conductive piece, the conductive piece can pull the insulating ring 202 to move in the horizontal direction, so that the insulating ring 202 moves from the first limit position to the second limit position. As shown in Figure 6 The insulating ring 202 is in the second limit position. When the insulating ring 202 moves from the first limit position to the second limit position, the gear 204 can engage with the rack 110, so that the insulating ring 202 can rotate around its own axis by a set angle, so that the two conductive pieces 301 of the conductive piece can be conductively connected with the conductive part 203 corresponding to the next heating wire 201 adjacent to it. When the sample gas containing VOCs is ignited again, it is realized by the energization of the next heating wire 201, avoiding the damage caused by the multiple use of a single heating wire 201, and prolonging the service life of the continuous monitoring device of air VOCs concentration.

[0048] Due to the combustion of the sample gas containing VOCs, the temperature of the detector body is increased, so that the gas in the telescopic bag 404 is gasified and expanded, and when the insulating ring 202 moves to the second limit position, the blocking plate 3021 at the bottom of the insulating plate 302 no longer blocks the cleaning ring 401, so that the cleaning ring 401 can move upward under the push of the telescopic bag 404, and in turn drive the scraping ring 403 to clean the inner wall of the collecting electrode 105. The scraped pollutants are discharged with the gas.

[0049] Finally, after stopping supplying the gas to the nozzle 102, the temperature of the detector body is reduced, the telescopic bag 404 is liquefied and shrinks, and the cleaning ring 401 is reset downward. Under the action of the first reset spring 304, the insulating ring 202 and the conductive piece are restored to the initial state, and the insulating ring 202 moves from the second limit position to the first limit position without rotating the insulating ring 202.

[0050] An embodiment of a continuous monitoring method of air VOCs concentration, which adopts the continuous monitoring device of air VOCs concentration described above, comprises the following steps: S1, supplying the sample gas containing VOCs into the detector body; S2, energizing the heating wire 201 through the conductive piece, so that the heating wire 201 ignites the sample gas containing VOCs; S3, the collecting electrode 105 continuously monitors the ions generated when the sample gas containing VOCs is burned, and generates a micro-current signal; S4, calculating the air VOCs concentration according to the micro-current signal.

[0051] Any combination of the technical features in the above embodiments can be made, and for the sake of brevity, not all possible combinations are described above. However, any combination of the technical features is deemed to be within the scope of the present disclosure as long as such a combination does not result in an inconsistency.

[0052] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the present application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A continuous monitoring device of air VOCs concentration, characterized in that, The application relates to a device for continuously monitoring the concentration of VOCs in air, which comprises: a detector body, which is provided with a gas outlet for burning and discharging sample gas containing VOCs, and which is internally provided with a collecting electrode in the form of a cylinder, the axis of the collecting electrode extending in the up-down direction; an ignition assembly located in the gas outlet and above the collecting electrode, which comprises an insulating ring and an electrically-conductive piece; the axis of the insulating ring extends in the up-down direction, and a plurality of heating wires are uniformly distributed in the circumferential direction of the insulating ring; the electrically-conductive piece is used for electrifying the heating wires, and the electrified heating wires can ignite the sample gas containing VOCs; the electrically-conductive piece has a first end and a second end which are distributed in the horizontal direction, the first end is arranged in sliding mode on the detector body in the horizontal direction, and the second end is rotationally connected with the insulating ring; when the sample gas containing VOCs is ignited and flows through the electrically-conductive piece, the electrically-conductive piece can pull the insulating ring to move in the horizontal direction, so that the insulating ring moves from a first limit position to a second limit position, at the first limit position, the axis of the insulating ring is located on one side of the axis of the collecting electrode, and at the second limit position, the axis of the insulating ring coincides with the axis of the collecting electrode; a one-way transmission mechanism, which can drive the insulating ring to rotate around its axis by a set angle when the insulating ring moves from the first limit position to the second limit position, so that the electrically-conductive piece can be in electrically-conductive connection with the adjacent next heating wire.

2. The apparatus for continuous monitoring of air VOCs concentration according to claim 1, wherein, The circumferential direction of the insulating ring is uniformly provided with a plurality of electrically-conductive parts, the heating wire is located between two adjacent electrically-conductive parts, and the two ends of the heating wire are in electrically-conductive connection with the two electrically-conductive parts respectively, the second end of the electrically-conductive piece is provided with two electrically-conductive sheets which are in the form of inverted U and are clamped on the insulating ring, the interval between two adjacent electrically-conductive sheets is equal to the interval between two adjacent electrically-conductive parts, so that the two electrically-conductive sheets can be in electrically-conductive contact with two adjacent electrically-conductive parts at the same time, thereby realizing the electrification of the heating wire.

3. The apparatus for continuous monitoring of air VOCs concentration according to claim 2, wherein, The electrically-conductive piece further comprises an insulating plate which extends in the vertical direction, the two electrically-conductive sheets are fixedly arranged on the same side surface of the insulating plate, the insulating plate is provided with a guide plate which is arranged in an inclined mode relative to the up-down direction, and the guide plate can push the insulating ring to move in the horizontal direction after the sample gas containing VOCs is ignited, thereby pulling the insulating ring to move in the horizontal direction through the electrically-conductive sheets.

4. The device for continuously monitoring the concentration of VOCs in air according to claim 3, characterized in that: an end cover is detachably connected to the upper end of the detector body, the end cover is provided with two guide holes, the first end of the electrically-conductive piece is provided with two electrically-conductive rods which are fixedly arranged on the same side surface of the insulating plate away from the electrically-conductive sheets, the electrically-conductive rods are in one-to-one correspondence with the guide holes and are in sliding connection, a first reset spring is sleeved on the electrically-conductive rod, and the first reset spring has a tendency to make the insulating ring be in the first limit position.

5. The apparatus for continuous monitoring of air VOCs concentration according to claim 4, wherein, The one-way transmission mechanism comprises a rack and a pinion, the rack extends in the horizontal direction, the pinion is coaxially arranged on the insulation ring, the rack is arranged on the inner wall of the end cover through the second reset spring, the second reset spring has a tendency to make the rack close to the pinion; when the insulation ring moves from the first limit position to the second limit position, the pinion can engage with the rack, so that the insulation ring can rotate around its axis; when the insulation ring moves from the second limit position to the first limit position, the pinion and the rack can be slidingly engaged in the horizontal direction, so that the insulation ring can slide in the horizontal direction relative to the rack.

6. The apparatus for continuous monitoring of air VOCs concentration according to claim 5, wherein, Further comprising a cleaning assembly, the cleaning assembly comprises a cleaning ring, the cleaning ring is coaxially arranged with the collecting electrode and is supported on the upper end surface of the collecting electrode, the bottom of the cleaning ring is provided with a plurality of support rods uniformly distributed around the circumference thereof, the support rods extend in the up-down direction and are located in the collecting electrode, the outer circumferential surface of the support rod is provided with a scraping ring, the scraping ring is coaxially arranged with the collecting electrode and is in close contact with the inner wall of the collecting electrode, when the cleaning ring slides in the up-down direction, the scraping ring can clean the inner wall of the collecting electrode.

7. The apparatus for continuous monitoring of air VOCs concentration according to claim 6, wherein, The bottom of the insulation plate is provided with a blocking plate extending in the horizontal direction, when the insulation ring is in the first limit position, the blocking plate is in abutting engagement with the cleaning ring in the up-down direction, so as to prevent the upward movement of the cleaning ring; when the insulation ring moves to the second limit position, the cleaning ring can move upward.

8. The apparatus for continuous monitoring of air VOCs concentration according to claim 7, wherein, The detector body is further provided with a containing groove, the containing groove is located on one side of the collecting electrode; the containing groove is provided with an expansion bag, the lower end of the expansion bag is connected with the bottom of the containing groove, the upper end of the expansion bag is connected with the bottom of the cleaning ring, the expansion bag can expand and contract in the up-down direction, so as to drive the cleaning ring to move in the up-down direction.

9. The apparatus for continuous monitoring of air VOCs concentration according to claim 8, wherein, The inside of the expansion bag is filled with a low-boiling-point liquid, the low-boiling-point liquid can expand and contract with heat, so as to drive the expansion bag to expand and contract.

10. A method for continuously monitoring the concentration of VOCs in air using the apparatus for continuously monitoring the concentration of VOCs in air according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: S1, sample gas containing VOCs is introduced into the detector body; S2, the heating wire is electrified through the conductive part, so that the heating wire ignites the sample gas containing VOCs; S3, the collecting electrode continuously monitors the ions generated when the sample gas containing VOCs burns, and generates a micro-current signal; S4, according to the micro-current signal, the concentration of air VOCs is calculated.

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