Online automatic detection device and method for atmospheric pollutants of stationary pollution source

Abstract

The invention discloses a stationary pollution source atmospheric pollutant online automatic detection device and method, and belongs to the technical field of pollutant detection, the stationary pollution source atmospheric pollutant online automatic detection device comprises a lower collecting pipe, the bottom end of the lower collecting pipe is provided with a frequency conversion fan, and the input end of the bottom of the frequency conversion fan is provided with an air inlet mechanism. A plurality of groups of gas inlet mechanisms are arranged at the bottom of the lower collecting pipe, and a wide-range first concentration sensor is arranged on the side edge of the lower collecting pipe, so that multi-point sampling can be carried out in the use process, the concentration of a pollution source in flue gas is preliminarily detected, and then the concentration of the pollution source in the flue gas is accurately measured by utilizing a dilution mechanism on the upper collecting pipe. A certain amount of clean gas is injected into flue gas, the concentration of the flue gas is reduced in a certain proportion, finally, the flue gas is discharged from a plurality of groups of detection pipes, and a small-range second concentration sensor is used for detection, so that the device not only can perform multi-point sampling measurement in the use process, and data is more representative; in addition, through the second concentration sensor with a small measuring range, the detection precision is ensured.

Description

Technical Field

[0001] The present invention relates to an automatic detection device, in particular to an online automatic detection device for atmospheric pollutants from fixed pollution sources. The present invention also relates to an online automatic detection method for atmospheric pollutants from fixed pollution sources, in particular to a detection method, and belongs to the technical field of pollutant detection. Background Art

[0002] Online automatic detection of atmospheric pollutants from fixed pollution sources is the process of real-time and continuous monitoring of atmospheric pollutants such as sulfur dioxide, nitrogen oxides, particulate matter, and volatile organic compounds from fixed emission sources such as industrial enterprises and coal-fired power plants through automated technical means. It utilizes high-precision sensors, spectral analysis and other technologies, combined with on-site monitoring equipment, data transmission systems and cloud monitoring platforms to achieve real-time collection, transmission and analysis of pollutant concentrations. It has core functions such as excessive warning, enterprise governance optimization and regional air quality decision support, and is an important technical guarantee for China's atmospheric pollution prevention and control and refined environmental management.

[0003] In the prior art, for example, a patent with application number 201810655010.7 discloses an online automatic detection device for atmospheric pollutants from fixed pollution sources, comprising: a sampling part for collecting flue gas from a flue gas channel; a bypass pipeline for receiving the flue gas collected by the sampling part; a return air pipeline for transmitting the flue gas in the bypass pipeline back to the flue gas channel; an online sensor device, which is arranged in the bypass pipeline, for measuring the concentration of pollutants contained in the flue gas passing through the bypass pipeline. By setting up multiple sampling pipelines and corresponding solenoid valves, accurate detection of flue gas pollutants that exceed the range can be performed without setting up a large-range sensor.

[0004] Similar to the above application, there are still some shortcomings: During the sampling process, only the gas sample at a single position can be sampled. The smoke concentration at a single sampling position will fluctuate to a certain extent, and the data is not representative enough, which affects the accuracy of the detection. In addition, in the prior art, a large range and a small range are used. The accuracy of the equipment is higher when detecting low-concentration smoke, but the accuracy of the equipment is lower when detecting high-concentration smoke.

[0005] Therefore, an online automatic detection device and method for atmospheric pollutants from fixed pollution sources are designed to optimize the above-mentioned problems. Summary of the invention

[0006] The main purpose of the present invention is to provide an online automatic detection device and method for atmospheric pollutants from fixed pollution sources. By arranging multiple groups of air intake mechanisms at the bottom of the lower manifold and arranging a first concentration sensor with a large range on the side of the lower manifold, multi-point sampling can be performed during use, and the concentration of the pollution source in the flue gas can be preliminarily detected. Then, a certain amount of clean gas is injected into the flue gas by using the dilution mechanism on the upper manifold to reduce the concentration of the flue gas by a certain proportion, and finally the flue gas is discharged from multiple groups of detection tubes and detected by using a second concentration sensor with a small range, so that the device can not only perform multi-point sampling and measurement during use, but also make the data more representative. In addition, The second concentration sensor with a small measuring range ensures the accuracy of detection. The air intake mechanism consisting of the conduit, mounting sleeve, flange, mounting tube, sampling tube, hose, slip ring, first spring, first rack, first gear, and protective shell is evenly installed on the outside of the flue gas duct, so that the collected samples are more representative. In addition, during the installation process, the sampling tube can be automatically adjusted to be parallel to the flue gas flow direction, which is more practical and more convenient to install. The expansion mechanism consisting of the cover plate, sliding sleeve, straight rod, screw, fixing ring, second spring, baffle, second rack, and second gear can automatically expand with the change of gas flow during the flue gas dilution process, so it is more convenient to use.

[0007] The purpose of the present invention can be achieved by adopting the following technical solutions: An online automatic detection device for atmospheric pollutants from a fixed pollution source comprises a lower manifold, a variable frequency fan is installed at the bottom end of the lower manifold, an air intake mechanism is arranged at the input end of the bottom of the variable frequency fan, the number of the air intake mechanisms is not less than three groups, and a first wind speed sensor is installed on each of the air intake mechanisms, a first concentration sensor is arranged on the side of the lower manifold and located on the top of the variable frequency fan, a second gas flow sensor is arranged on the side of the first concentration sensor, a controller is installed on the top of the outer side of the lower manifold, an upper manifold is installed on the top of the lower manifold, the inner diameter of the upper manifold is larger than the inner diameter of the lower manifold, and the upper manifold is provided at the top of the lower manifold. A dilution mechanism is provided on the manifold, and the top of the upper manifold is evenly installed with detection tubes of the same number as the air intake mechanism, and the tops of the sides of the detection tubes are all installed with second concentration sensors, and the sides of the detection tubes and below the second concentration sensors are all provided with second wind speed sensors, and the tops of the detection tubes are fixed with circulation tubes, and the circulation tubes are installed on the flue gas duct, and the top of the upper manifold is provided with an expansion mechanism, and the variable frequency fan, the first concentration sensor, the first wind speed sensor, the dilution mechanism, the second wind speed sensor, the second concentration sensor and the second gas flow sensor are all electrically connected to the controller through wires.

[0008] Preferably: the air intake mechanism includes a duct, a mounting sleeve, a flange, a mounting tube, a sampling tube, a hose and a rotating assembly, the top of the duct is connected to the input end of the variable frequency fan, the outer sleeve of the bottom end of the duct is provided with a mounting sleeve, the end of the mounting sleeve is fixed with a flange, the side of the duct is fixedly connected to the flange, the mounting tube is rotatably installed at the end of the mounting sleeve away from the flange, the sampling tube is fixedly installed inside the mounting tube, the first wind speed sensor is installed on the side of the sampling tube, a hose is provided between the end of the sampling tube and the end of the duct, a rotating assembly for controlling the rotation of the mounting tube is provided on the outside of the mounting sleeve, and the maximum rotation angle of the mounting tube is 90°.

[0009] Preferably: the rotating assembly includes a slip ring, a first spring, a first rack, a first gear and a protective shell, the slip ring sleeve is arranged on the outside of the mounting sleeve, the first spring is fixed between the side of the mounting sleeve and the flange, the first rack is symmetrically arranged on the side of the slip ring, the first gear is symmetrically rotatably installed on both sides of the mounting sleeve near one end of the mounting tube, the first gear is connected to the mounting tube through a shaft rod, and the first rack is meshed with the first gear.

[0010] Preferably, a protective shell is symmetrically arranged on the outer side of the installation sleeve, the first gear is located inside the protective shell, and the first rack passes horizontally through the inside of the protective shell.

[0011] Preferably: the dilution mechanism includes an air filter assembly, an annular tube and an air hole, the annular tube is horizontally fixed on the outer side of the upper manifold, an air hole is opened between the inner side of the annular tube and the upper manifold, the interior of the annular tube is connected to the interior of the upper manifold through the air hole, an air filter assembly is installed on the outer side of the upper manifold, and the air filter assembly is connected to the interior of the annular tube.

[0012] Preferably: the air filter assembly includes a mounting frame, a filter cartridge, a filter element, an air pump, a straight pipe and a first gas flow sensor; the mounting frame is fixed to the side of the upper manifold, the filter cartridge is installed on the mounting frame, the filter element is installed on the inner top of the filter cartridge, the air pump is installed on the top of the filter cartridge, a straight pipe is installed between the output end of the air pump and the annular pipe, the first gas flow sensor is provided inside the straight pipe, and the air pump and the first gas flow sensor are electrically connected to the controller through a wire.

[0013] Preferably: a rotating rod is vertically installed at the middle position inside the upper manifold, a blade is rotatably installed on the top of the rotating rod, and the blade and the air hole are located in the same horizontal plane.

[0014] Preferably: the expansion mechanism includes a cover plate, a sliding sleeve and a lifting assembly, the cover plate is arranged on the top of the upper manifold, and the cover plate is vertically slidably connected to the detection tube, a sliding sleeve is fixed to the bottom of the cover plate, the sliding sleeve is located inside the upper manifold and is slidably connected to the upper manifold, and a lifting assembly is provided on the outer side of the cover plate.

[0015] Preferably: the lifting assembly includes a straight rod, a screw rod, a fixing ring, a second spring, a baffle, a second rack and a second gear. The straight rod is horizontally fixed to the outer side of the cover plate, and a screw rod is threadedly installed on the straight rod. The screw rod is parallel to the straight direction of the upper collecting pipe, and the bottom end of the screw rod extends to the inside of the second gear rod, and the screw rod and the straight pipe are rotatably connected. The second gear rod is fixed to the bottom end of the screw rod, and a fixing ring is fixed to the inner side of the straight pipe. A second spring is fixed to the side of the fixing ring close to the annular pipe, and a baffle is installed at the end of the second spring, and a second rack meshing with the second gear rod is installed on the side of the baffle.

[0016] The present invention also provides an online automatic detection method for atmospheric pollutants from fixed pollution sources, comprising the following steps: Step 1: Install the air intake mechanism evenly in the circumferential direction of the flue gas duct, and avoid the sampling point at the unstable airflow area such as elbows and reducers. Then fix the side of the lower manifold vertically on the flue gas duct. Finally, connect the circulation pipe with the flue gas duct to return the tested flue gas to the inside of the flue gas duct. Step 2: The flow rate of the gas inside the smoke duct is measured by the first wind speed sensor, and then the variable frequency fan is started by the controller to extract the smoke, and the extraction rate is the same as the flow rate of the smoke inside the smoke duct. The samples sampled at multiple points enter the lower manifold for mixing; Step 3: The first concentration sensor performs a rough check on the concentration of flue gas pollutants inside the lower manifold. When the detected concentration is greater than the maximum threshold of the second concentration sensor, the controller controls the dilution mechanism to inject clean gas into the upper manifold to dilute the flue gas concentration by a certain multiple. The diluted gas then enters the detection tube, and the flow rate of the flue gas inside the detection tube is the same as that inside the flue gas duct. The second concentration sensor is then used to accurately detect the concentration of pollutants in the flue gas, and the detected flue gas flows back to the flue gas duct. Step 4: If the pollutant concentration is high and the air intake volume during the dilution process of the dilution mechanism is large, resulting in the gas flow rate detected by the second wind speed sensor being greater than the flow rate during the air intake, the expansion mechanism is used to expand the upper manifold to ensure that the exhaust rate of the detection tube during the detection process is equal to the rate when the smoke enters; Step 5: Obtain an accurate measurement result based on the product of the dilution multiple of the flue gas by the dilution mechanism and the measurement result of the second concentration sensor.

[0017] The beneficial effects of the present invention are: The present invention provides an online automatic detection device and method for atmospheric pollutants from a fixed pollution source. By arranging multiple groups of air intake mechanisms at the bottom of a lower manifold and arranging a first concentration sensor with a large range on the side of the lower manifold, multi-point sampling can be performed during use, and the concentration of the pollution source in the flue gas can be preliminarily detected. Then, a certain amount of clean gas is injected into the flue gas by using the dilution mechanism on the upper manifold to reduce the concentration of the flue gas by a certain proportion, and finally the flue gas is discharged from multiple groups of detection tubes and detected by using a second concentration sensor with a small range. Therefore, the device can not only perform multi-point sampling and measurement during use, but also make the data more representative. In addition, the second concentration sensor with a small range can ensure the accuracy of the detection. By evenly installing the air intake mechanism consisting of the conduit, the mounting sleeve, the flange, the mounting pipe, the sampling pipe, the hose, the slip ring, the first spring, the first rack, the first gear, and the protective shell on the outside of the flue gas duct, the collected samples are more representative. In addition, during the installation process, the sampling pipe can be automatically adjusted to be parallel to the flue gas flow direction, which is more practical and more convenient to install. The expansion mechanism composed of a cover plate, a sliding sleeve, a straight rod, a screw rod, a fixing ring, a second spring, a baffle, a second rack and a second gear can automatically expand the capacity as the gas flow changes during the flue gas dilution process, making it more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a front view of a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention; Figure 2 It is a top-sectional view of the distribution of the air intake mechanism on the flue gas duct of a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention; Figure 3 This is a diagram of the initial state of the air intake mechanism of a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention; Figure 4 This is a sampling state diagram of an intake mechanism in a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention; Figure 5 This is a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention. Figure 4 Enlarged view of point A in the middle; Figure 6 A dilution mechanism diagram of a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention; Figure 7 This is a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention. Figure 6Enlarged view of point B in the middle; Figure 8 This is a structural diagram of a sliding sleeve of a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention.

[0019] In the figure: 1. Lower manifold; 2. Variable frequency fan; 3. First concentration sensor; 4. air intake mechanism; 401. conduit; 402. mounting sleeve; 403. flange; 404. mounting pipe; 405. sampling pipe; 406. hose; 407. slip ring; 408. first spring; 409. first rack; 410. first gear; 411. protective shell; 5. First wind speed sensor; 6. Controller; 7. upper manifold; 701. rotating rod; 702. blades; 8. dilution mechanism; 801. mounting frame; 802. filter cartridge; 803. filter element; 804. air pump; 805. annular tube; 806. straight tube; 807. air hole; 808. first gas flow sensor; 9. Detection tube; 10. Second wind speed sensor; 11. Second concentration sensor; 12. Circulation tube; 13. Expansion mechanism; 1301. Cover plate; 1302. Sliding sleeve; 1303. Straight rod; 1304. Screw rod; 1305. Fixed ring; 1306. Second spring; 1307. Baffle; 1308. Second rack; 1309. Second gear; 14. Second gas flow sensor. DETAILED DESCRIPTION

[0020] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below in conjunction with embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0021] like Figure 1-Figure 8As shown, the present embodiment provides an online automatic detection device for atmospheric pollutants from a fixed pollution source, comprising a lower manifold 1, a variable frequency fan 2 is installed at the bottom end of the lower manifold 1, an air intake mechanism 4 is provided at the input end of the bottom of the variable frequency fan 2, the number of the air intake mechanisms 4 is not less than three groups, and a first wind speed sensor 5 is installed on each of the air intake mechanisms 4, a first concentration sensor 3 is provided on the side of the lower manifold 1 and located at the top of the variable frequency fan 2, a second gas flow sensor 14 is provided on the side of the first concentration sensor 3, a controller 6 is installed on the top of the outer side of the lower manifold 1, an upper manifold 7 is installed on the top of the lower manifold 1, the inner diameter of the upper manifold 7 is larger than the inner diameter of the lower manifold 1, and the upper manifold 7 is provided at the top of the lower manifold 1. A dilution mechanism 8 is provided on the flow tube 7. The top of the upper conduit 7 is evenly installed with detection tubes 9 of the same number as the air intake mechanism 4. The top of the side of the detection tube 9 is installed with a second concentration sensor 11. The side of the detection tube 9 and below the second concentration sensor 11 are provided with a second wind speed sensor 10. A circulation tube 12 is fixed to the top of the detection tube 9, and the circulation tube 12 is installed on the flue gas duct. An expansion mechanism 13 is provided on the top of the upper conduit 7. The variable frequency fan 2, the first concentration sensor 3, the first wind speed sensor 5, the dilution mechanism 8, the second wind speed sensor 10, the second concentration sensor 11 and the second gas flow sensor 14 are all electrically connected to the controller 6 through wires.

[0022] The overall working principle is as follows: first, the air intake mechanism 4 is evenly installed in the circumferential direction of the smoke duct, the angles between adjacent air intake mechanisms 4 are the same, and the sampling points avoid unstable airflow areas such as elbows and reducers, and then the side of the lower manifold 1 is vertically fixed on the smoke duct, and finally the circulation pipe 12 is connected to the smoke duct to return the detected smoke to the inside of the smoke duct. After the device is installed, when it is necessary to detect, first measure the flow rate of the gas inside the smoke duct through the first wind speed sensor 5, and then use the controller 6 to control the start of the variable frequency fan 2 to extract the smoke, and the extraction rate is the same as the flow rate of the smoke inside the smoke duct. The samples sampled at multiple points enter the lower manifold 1 for mixing, and the first concentration sensor 3 performs a rough inspection on the concentration of smoke pollutants inside the lower manifold 1. When the detected concentration is greater than the maximum threshold value of the second concentration sensor 11, the controller 6 controls the dilution mechanism 8 to inject clean gas into the upper manifold 7 to adjust the smoke concentration. A certain multiple dilution is performed, and then the diluted gas enters the interior of the detection tube 9, and the flow rate of the flue gas in the detection tube 9 is the same as the flow rate inside the flue gas duct, Qintake = Qdetection + Qdilution, and then the second concentration sensor 11 is used to accurately detect the concentration of pollutants in the flue gas. The flue gas after detection flows back to the interior of the flue gas duct. If the pollutant concentration is high, the air intake volume during the dilution process of the dilution mechanism 8 is large, resulting in the gas flow rate detected by the second wind speed sensor 10 being greater than the flow rate during intake. At this time, the expansion mechanism 13 is used to expand the upper manifold 7 to ensure that the exhaust rate of the detection tube 9 during the detection process is equal to the rate when the flue gas enters. According to the dilution multiple of the flue gas by the dilution mechanism 8 and the product of the measurement result of the second concentration sensor 11, an accurate measurement result is obtained, Creal = Cdetection × (Qsmoke + Qdilution) / Qsmoke. The flue gas flow is monitored by the second gas flow sensor 14, and the first gas flow sensor 808 monitors the diluted gas flow.

[0023] In this embodiment, the air intake mechanism 4 includes a conduit 401, a mounting sleeve 402, a flange 403, a mounting tube 404, a sampling tube 405, a hose 406 and a rotating assembly. The top of the conduit 401 is connected to the input end of the variable frequency fan 2, the outer sleeve of the bottom end of the conduit 401 is provided with a mounting sleeve 402, the end of the mounting sleeve 402 is fixed with a flange 403, the side of the conduit 401 is fixedly connected to the flange 403, the end of the mounting sleeve 402 is rotatably installed with the mounting tube 404 away from the flange 403, the inside of the mounting tube 404 is fixedly installed with the sampling tube 405, the first wind speed sensor 5 is installed on the side of the sampling tube 405, a hose 406 is provided between the end of the sampling tube 405 and the end of the conduit 401, and a rotating assembly for controlling the rotation of the mounting tube 404 is provided on the outer side of the mounting sleeve 402, and the maximum rotation angle of the mounting tube 404 is 90°.

[0024] Local working principle: During the installation of the air intake mechanism 4, in its initial form, the air intake mechanism 4 is linear. Align the air intake mechanism 4 with the installation port on the side of the flue gas duct, and then insert the sampling tube 405 and the installation sleeve 402 into it. Then use bolts to fix the flange 403 on the flange at the installation port, and use the sealing ring between the flanges to seal. After the insertion is completed, use the rotating assembly to flip the sampling tube 405 downward by ninety degrees. The sampling tube 405 is parallel to the gas flow direction, and the flue gas enters from the bottom end of the sampling tube 405.

[0025] In this embodiment, the rotating assembly includes a slip ring 407, a first spring 408, a first rack 409, a first gear 410 and a protective shell 411. The slip ring 407 is sleeved on the outside of the mounting sleeve 402. The first spring 408 is fixed between the side of the mounting sleeve 402 and the flange 403. The first rack 409 is symmetrically arranged on the side of the slip ring 407. The first gear 410 is symmetrically rotatably installed on both sides of the mounting sleeve 402 near one end of the mounting tube 404. The first gear 410 is connected to the mounting tube 404 through a shaft, and the first rack 409 is meshed with the first gear 410.

[0026] Local working principle: During the insertion of the mounting sleeve 402, the slip ring 407 will be blocked at the end of the mounting port. As the mounting sleeve 402 is continuously inserted, the first rack 409 slides relative to the linear direction of the mounting sleeve 402. The movement of the first rack 409 drives the first gear 410 to rotate, thereby controlling the mounting tube 404 and the sampling tube 405 inside it to rotate downward. After the flange 403 is fixed, the rotation angle of the sampling tube 405 is also fixed.

[0027] In this embodiment, a protective shell 411 is symmetrically arranged on the outer side of the installation sleeve 402 , the first gear 410 is located inside the protective shell 411 , and the first rack 409 passes horizontally through the inside of the protective shell 411 .

[0028] Partial working principle: The use of the protective shell 411 can protect the meshing position of the first gear 410 and the first rack 409.

[0029] In this embodiment, the dilution mechanism 8 includes an air filter assembly, an annular tube 805 and an air hole 807. The annular tube 805 is horizontally fixed on the outer side of the upper collector pipe 7. The air hole 807 is opened between the inner side of the annular tube 805 and the upper collector pipe 7. The interior of the annular tube 805 is connected to the interior of the upper collector pipe 7 through the air hole 807. The air filter assembly is installed on the outer side of the upper collector pipe 7, and the air filter assembly is connected to the interior of the annular tube 805.

[0030] Local working principle: When the flue gas inside the upper collector 7 needs to be diluted, the air filter assembly is used to filter the outside air to remove substances in the air that are the same as the detected flue gas components, so as to avoid the diluted air from affecting the pollutant concentration. The gas is then injected into the interior of the annular tube 805 and then enters the interior of the upper collector 7 through the air hole 807 to dilute the flue gas.

[0031] In this embodiment, the air filter assembly includes a mounting frame 801, a filter cartridge 802, a filter element 803, an air pump 804, a straight pipe 806 and a first gas flow sensor 808. The mounting frame 801 is fixed to the side of the upper manifold 7, the filter cartridge 802 is installed on the mounting frame 801, the filter element 803 is installed on the inner top of the filter cartridge 802, the air pump 804 is installed on the top of the filter cartridge 802, a straight pipe 806 is installed between the output end of the air pump 804 and the annular pipe 805, the first gas flow sensor 808 is arranged inside the straight pipe 806, and the air pump 804 and the first gas flow sensor 808 are electrically connected to the controller 6 through a wire.

[0032] Partial working principle: Controller 6 controls the start of air pump 804, which extracts gas from the inside of filter cartridge 802, and the gas passes through filter element 803 to filter out substances with the same components as the detected flue gas. Filter element 803 material: PTFE membrane with a pore size of 0.1 μm, which is effective for SO 2 The removal rate of target pollutants such as NOx is ≥99.9%, and the filtration efficiency is still ≥95% after 1000 hours of continuous operation. Then, the interior of the annular tube 805 is injected through the straight tube 806, and the first gas flow sensor 808 detects the amount of injected gas to ensure the accurate ratio of flue gas to dilution gas.

[0033] In this embodiment, a rotating rod 701 is vertically installed at the middle position inside the upper manifold 7, and a blade 702 is rotatably installed at the top of the rotating rod 701. The blade 702 and the air hole 807 are located at the same horizontal plane.

[0034] Local working principle: After the diluted gas enters the interior of the upper manifold 7, the gas will blow on the blades 702 to control the rotation of the blades 702. The blades 702 will mix and stir the flue gas with the absorption gas to ensure that the gas pollutant content discharged from the detection tube 9 is uniform.

[0035] In this embodiment, the expansion mechanism 13 includes a cover plate 1301, a sliding sleeve 1302 and a lifting assembly. The cover plate 1301 is arranged on the top of the upper manifold 7, and the cover plate 1301 is vertically slidably connected to the detection tube 9. The sliding sleeve 1302 is fixed to the bottom of the cover plate 1301. The sliding sleeve 1302 is located inside the upper manifold 7 and is slidably connected to the upper manifold 7. A lifting assembly is provided on the outer side of the cover plate 1301.

[0036] Partial working principle: When the concentration of pollutants is too high and a large amount of dilution gas is required to reach the detection range of the second concentration sensor 11, the lifting assembly is used to control the cover plate 1301 and the sleeve 1302 to move upward. The side of the sleeve 1302 adopts a double-lip sealing ring structure, the material is fluororubber, the sealing pressure requirement is 0.1-0.5MPa, and the graphite coating is self-lubricated. The volume inside the sleeve 1302 and the upper manifold 7 increases, thereby reducing the flow rate of the gas flowing out of the detection tube 9 after dilution, ensuring that it is the same as the flow rate during intake. When the diameter of the detection tube 9 remains unchanged, the exhaust rate (volume flow rate) is determined by the flow rate. According to the small hole flow rate formula (Ignoring viscosity and temperature changes), an increase in the pressure P on the upper manifold 7 will cause an increase in the flow velocity v, thereby increasing the exhaust rate. A decrease in the pressure on the upper manifold 7 will reduce the flow velocity and the exhaust rate. During the detection process, the capacity of the upper manifold 7 increases to a greater extent, the pressure drops, and the exhaust rate decreases, thereby achieving a reduction in the rate when flowing out of the detection tube 9.

[0037] In this embodiment, the lifting assembly includes a straight rod 1303, a screw rod 1304, a fixing ring 1305, a second spring 1306, a baffle 1307, a second rack 1308 and a second gear 1309. The straight rod 1303 is horizontally fixed on the outer side of the cover plate 1301. The screw rod 1304 is threadedly mounted on the straight rod 1303. The screw rod 1304 is parallel to the straight direction of the upper manifold 7. The bottom end of the screw rod 1304 extends to the second gear 1309. 9, and the screw rod 1304 is rotatably connected with the straight tube 806, a second gear 1309 is fixed to the bottom end of the screw rod 1304, a fixing ring 1305 is fixed to the inner side of the straight tube 806, a second spring 1306 is fixed to the side of the fixing ring 1305 close to the annular tube 805, a baffle 1307 is installed at the end of the second spring 1306, and a second rack 1308 meshing with the second gear 1309 is installed on the side of the baffle 1307.

[0038] Local working principle: When a large amount of diluted gas is discharged from the inside of the straight pipe 806, a large thrust will be applied to the baffle 1307. At this time, the baffle 1307 will drive the second rack 1308 to move in a straight line, and the second rack 1308 will drive the second gear 1309 to rotate. The second gear 1309 controls the rotation of the screw 1304, thereby lifting the position of the cover 1301. When the airflow decreases, the baffle 1307 will return to its original position under the reset action of the second spring 1306.

[0039] like Figure 1-Figure 8 As shown, this embodiment provides a method for online automatic detection of atmospheric pollutants from fixed pollution sources, and the process is as follows: Step 1: Install the air intake mechanism 4 evenly in the circumferential direction of the flue gas duct, and avoid the sampling point at the unstable airflow area such as elbows and reducers, and then vertically fix the side of the lower manifold 1 on the flue gas duct, and finally connect the circulation pipe 12 with the flue gas duct to return the detected flue gas to the inside of the flue gas duct; Step 2: The flow rate of the gas inside the smoke duct is measured by the first wind speed sensor 5, and then the variable frequency fan 2 is controlled by the controller 6 to start, and the smoke is extracted, and the extraction rate is the same as the flow rate of the smoke inside the smoke duct, and the samples sampled at multiple points enter the lower manifold 1 for mixing; Step 3: The first concentration sensor 3 performs a rough check on the concentration of flue gas pollutants inside the lower manifold 1. When the detected concentration is greater than the maximum threshold of the second concentration sensor 11, the controller 6 controls the dilution mechanism 8 to inject clean gas into the upper manifold 7 to dilute the flue gas concentration by a certain multiple. The diluted gas then enters the detection tube 9, and the flow rate of the flue gas inside the detection tube 9 is the same as the flow rate inside the flue gas duct. The second concentration sensor 11 is then used to accurately detect the concentration of pollutants in the flue gas, and the detected flue gas flows back to the flue gas duct. Step 4: If the pollutant concentration is high and the air intake volume during the dilution process of the dilution mechanism 8 is large, resulting in the gas flow rate detected by the second wind speed sensor 10 being greater than the flow rate during the intake, the expansion mechanism 13 is used to expand the upper manifold 7 to ensure that the exhaust rate of the detection tube 9 during the detection process is equal to the rate when the smoke enters; Step 5: Obtain an accurate measurement result based on the product of the dilution multiple of the flue gas by the dilution mechanism 8 and the measurement result of the second concentration sensor 11.

[0040] The above description is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which belong to the protection scope of the present invention.

Claims

1. An online automatic detection device for atmospheric pollutants from a fixed pollution source, comprising a lower manifold (1), characterized in that: A variable frequency fan (2) is installed at the bottom end of the lower manifold (1), an air intake mechanism (4) is provided at the input end of the bottom of the variable frequency fan (2), the number of the air intake mechanisms (4) is not less than three groups, and a first wind speed sensor (5) is installed on each of the air intake mechanisms (4), a first concentration sensor (3) is provided on the side of the lower manifold (1) and located on the top of the variable frequency fan (2), a second gas flow sensor (14) is provided on the side of the first concentration sensor (3), a controller (6) is installed on the top of the outer side of the lower manifold (1), an upper manifold (7) is installed on the top of the lower manifold (1), the inner diameter of the upper manifold (7) is larger than the inner diameter of the lower manifold (1), a dilution mechanism (8) is provided on the upper manifold (7), and the upper manifold (7) has a The same number of detection tubes (9) as the air intake mechanism (4) are evenly installed at the top, the top of the side of the detection tube (9) is installed with a second concentration sensor (11), the side of the detection tube (9) and below the second concentration sensor (11) is provided with a second wind speed sensor (10), the top of the detection tube (9) is fixed with a circulation tube (12), and the circulation tube (12) is installed on the flue gas duct, the top of the upper confluence pipe (7) is provided with an expansion mechanism (13), and the variable frequency fan (2), the first concentration sensor (3), the first wind speed sensor (5), the dilution mechanism (8), the second wind speed sensor (10), the second concentration sensor (11) and the second gas flow sensor (14) are all electrically connected to the controller (6) through wires.

2. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 1 is characterized by: The air intake mechanism (4) comprises a conduit (401), a mounting sleeve (402), a flange (403), a mounting pipe (404), a sampling pipe (405), a hose (406) and a rotating assembly. The top end of the conduit (401) is connected to the input end of the variable frequency fan (2). The outer sleeve of the bottom end of the conduit (401) is provided with a mounting sleeve (402). The end of the mounting sleeve (402) is fixed with a flange (403). The side of the conduit (401) is fixedly connected to the flange (403). The mounting sleeve A mounting tube (404) is rotatably mounted on one end of the mounting sleeve (402) away from the flange (403), a sampling tube (405) is fixedly mounted inside the mounting tube (404), a first wind speed sensor (5) is mounted on the side of the sampling tube (405), a hose (406) is provided between the end of the sampling tube (405) and the end of the conduit (401), a rotating assembly for controlling the rotation of the mounting tube (404) is provided on the outside of the mounting sleeve (402), and the maximum rotation angle of the mounting tube (404) is 90°.

3. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 2 is characterized by: The rotating assembly comprises a slip ring (407), a first spring (408), a first rack (409), a first gear (410) and a protective shell (411); the slip ring (407) is sleeved on the outside of the mounting sleeve (402); a first spring (408) is fixed between the side of the mounting sleeve (402) and the flange (403); a first rack (409) is symmetrically arranged on the side of the slip ring (407); first gears (410) are symmetrically rotatably mounted on both sides of the mounting sleeve (402) near one end of the mounting tube (404); the first gear (410) is connected to the mounting tube (404) via a shaft rod; and the first rack (409) is meshed with the first gear (410).

4. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 3 is characterized by: A protective shell (411) is symmetrically arranged on the outer side of the mounting sleeve (402), the first gear (410) is located inside the protective shell (411), and the first rack (409) passes horizontally through the inside of the protective shell (411).

5. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 1 is characterized by: The dilution mechanism (8) comprises an air filter assembly, an annular tube (805) and an air hole (807); the annular tube (805) is horizontally fixed to the outer side of the upper manifold (7); an air hole (807) is provided between the inner side of the annular tube (805) and the upper manifold (7); the interior of the annular tube (805) is connected to the interior of the upper manifold (7) through the air hole (807); an air filter assembly is installed on the outer side of the upper manifold (7); the air filter assembly is connected to the interior of the annular tube (805).

6. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 5 is characterized by: The air filter assembly comprises a mounting frame (801), a filter cartridge (802), a filter element (803), an air pump (804), a straight pipe (806) and a first gas flow sensor (808); the mounting frame (801) is fixed to the side of an upper manifold (7); the filter cartridge (802) is mounted on the mounting frame (801); the filter element (803) is mounted on the inner top of the filter cartridge (802); the air pump (804) is mounted on the top of the filter cartridge (802); a straight pipe (806) is mounted between the output end of the air pump (804) and the annular pipe (805); a first gas flow sensor (808) is arranged inside the straight pipe (806); and the air pump (804) and the first gas flow sensor (808) are electrically connected to a controller (6) via a wire.

7. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 6 is characterized by: A rotating rod (701) is vertically mounted at the middle position inside the upper manifold (7), and a blade (702) is rotatably mounted on the top of the rotating rod (701), wherein the blade (702) and the air hole (807) are located at the same horizontal plane.

8. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 7 is characterized by: The expansion mechanism (13) comprises a cover plate (1301), a sliding sleeve (1302) and a lifting assembly. The cover plate (1301) is arranged on the top of the upper manifold (7), and the cover plate (1301) is vertically slidably connected to the detection tube (9). The bottom of the cover plate (1301) is fixed with a sliding sleeve (1302), and the sliding sleeve (1302) is located inside the upper manifold (7) and is slidably connected to the upper manifold (7). The lifting assembly is arranged on the outside of the cover plate (1301).

9. The online automatic detection device for atmospheric pollutants from fixed pollution sources according to claim 8 is characterized by: The lifting assembly comprises a straight rod (1303), a screw rod (1304), a fixing ring (1305), a second spring (1306), a baffle (1307), a second rack (1308) and a second gear (1309). The straight rod (1303) is horizontally fixed on the outside of the cover plate (1301). The screw rod (1304) is threadedly mounted on the straight rod (1303). The screw rod (1304) is parallel to the straight direction of the upper manifold (7). The bottom end of the screw rod (1304) extends to the inside of the second gear (1309). The screw rod (1304) and the straight tube (806) are rotatably connected, a second gear (1309) is fixed to the bottom end of the screw rod (1304), a fixing ring (1305) is fixed to the inner side of the straight tube (806), a second spring (1306) is fixed to the side of the fixing ring (1305) close to the annular tube (805), a baffle (1307) is installed at the end of the second spring (1306), and a second rack (1308) meshing with the second gear (1309) is installed on the side of the baffle (1307).

10. An online automatic detection method for atmospheric pollutants from stationary pollution sources, based on an online automatic detection device for atmospheric pollutants from stationary pollution sources according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: The air intake mechanism (4) is evenly installed in the circumferential direction of the flue gas duct, and the sampling point is away from the unstable air flow area such as the elbow and the reducer, and then the side of the lower manifold (1) is vertically fixed on the flue gas duct, and finally the circulation pipe (12) is connected to the flue gas duct to return the detected flue gas to the inside of the flue gas duct; Step 2: The flow rate of the gas inside the smoke duct is measured by a first wind speed sensor (5), and then the variable frequency fan (2) is started by a controller (6) to extract the smoke, and the extraction rate is the same as the flow rate of the smoke inside the smoke duct. The samples sampled at multiple points enter the lower manifold (1) for mixing; Step 3: The first concentration sensor (3) performs a rough check on the concentration of the flue gas pollutants inside the lower manifold (1). When the detected concentration is greater than the maximum threshold value of the second concentration sensor (11), the controller (6) controls the dilution mechanism (8) to inject clean gas into the upper manifold (7) to dilute the flue gas concentration by a certain multiple. The diluted gas then enters the detection tube (9), and the flow rate of the flue gas inside the detection tube (9) is the same as the flow rate inside the flue gas duct. The second concentration sensor (11) is then used to accurately detect the concentration of the pollutants in the flue gas, and the flue gas after detection flows back into the flue gas duct. Step 4: If the pollutant concentration is high and the air intake volume during the dilution process of the dilution mechanism (8) is large, resulting in the gas flow rate detected by the second wind speed sensor (10) being greater than the flow rate during air intake, the upper manifold (7) is expanded using the expansion mechanism (13) to ensure that the exhaust rate of the detection tube (9) during the detection process is equal to the rate when the smoke enters; Step 5: Obtain an accurate measurement result based on the product of the dilution factor of the flue gas by the dilution mechanism (8) and the measurement result of the second concentration sensor (11).

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