An online automatic detection device and method for atmospheric pollutants from fixed pollution sources

Abstract

The present invention discloses an online automatic detection device and method for atmospheric pollutants from fixed pollution sources, belonging to the field of pollutant detection technology. The device comprises a lower manifold, a variable frequency fan is installed at the bottom end of the lower manifold, and an air intake mechanism is provided at the input end of the bottom of the variable frequency fan. The present invention provides multiple sets of air intake mechanisms at the bottom of the lower manifold, and a first concentration sensor with a large range is provided on the side of the lower manifold. During use, the device can perform multi-point sampling and preliminary detection of the concentration of the pollution source in the flue gas. Then, a certain amount of clean gas is injected into the flue gas using the dilution mechanism on the upper manifold to reduce the concentration of the flue gas by a certain proportion. Finally, the flue gas is discharged from the multiple detection tubes and detected using a second concentration sensor with a small range. This allows the device to not only perform multi-point sampling and measurement during use, but also to obtain more representative data. In addition, the second concentration sensor with a small range ensures the accuracy of the detection.

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 stationary pollution sources is a process of real-time and continuous monitoring of atmospheric pollutants such as sulfur dioxide, nitrogen oxides, particulate matter, and volatile organic compounds from stationary emission sources such as industrial enterprises and coal-fired power plants through automated technology. It utilizes high-precision sensors, spectral analysis and other technologies, combined with on-site monitoring equipment, data transmission systems and cloud-based monitoring platforms to achieve real-time collection, transmission and analysis of pollutant concentrations. It has core functions such as warning of exceeding standards, 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, the patent with application number 201810655010.7 discloses an online automatic detection device for atmospheric pollutants from fixed pollution sources, which includes: a sampling part for collecting flue gas from a flue gas channel; a bypass pipe for receiving the flue gas collected by the sampling part; a return air pipe for transmitting the flue gas in the bypass pipe back to the flue gas channel; an online sensing device, which is arranged in the bypass pipe and is used to measure the concentration of pollutants contained in the flue gas passing through the bypass pipe. By setting up multiple sampling pipes and corresponding solenoid valves, flue gas pollutants that exceed the range can be accurately detected without setting up a large-range sensor.

[0004] Similar to the above application, there are still some deficiencies:

[0005] During the sampling process, only gas samples at a single location can be sampled. The smoke concentration at a single sampling location will fluctuate to a certain extent, and the data is not representative enough, which affects the accuracy of the detection. In addition, in the existing technology, 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.

[0006] Therefore, an online automatic detection device and method for atmospheric pollutants from fixed pollution sources are designed to optimize the above problems. Summary of the Invention

[0007] 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 a first concentration sensor with a large range is arranged 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. Finally, the flue gas is discharged from the multiple groups of detection tubes and detected by the second concentration sensor with a small range. In this way, 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 a conduit, a mounting sleeve, a flange, a mounting tube, a sampling tube, a hose, a slip ring, a first spring, a first rack, a first gear, and a 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 direction of flue gas flow, which is more practical and more convenient to install. The expansion mechanism consisting of a cover plate, a sliding sleeve, a straight rod, a screw, a fixing ring, a second spring, a baffle, a second rack, and a second gear can automatically expand as the gas flow changes during the flue gas dilution process, making it more convenient to use.

[0008] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0009] 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 provided 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 provided on the side of the lower manifold and located on the top of the variable frequency fan, a second gas flow sensor is provided 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 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. A second concentration sensor is installed on the top of the side of the detection tube, and a second wind speed sensor is provided on the side of the detection tube and below the second concentration sensor. A circulation tube is fixed on the top of the detection tube, and the circulation tube is installed on the flue gas duct. An expansion mechanism is provided on the top of the upper manifold, 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.

[0010] Preferably: the air intake mechanism includes a conduit, a mounting sleeve, a flange, a mounting tube, a sampling tube, a hose and a rotating assembly, the top of the conduit is connected to the input end of the variable frequency fan, the outer sleeve of the bottom end of the conduit is provided with a mounting sleeve, the end of the mounting sleeve is fixed with a flange, the side of the conduit 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 conduit, 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°.

[0011] 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 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, and the first rack is meshed with the first gear.

[0012] Preferably, a protective shell is symmetrically arranged on the outer side of the mounting sleeve, the first gear is located inside the protective shell, and the first rack passes horizontally through the inside of the protective shell.

[0013] 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 edge 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.

[0014] 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.

[0015] Preferably, a rotating rod is vertically installed at the middle position inside the upper manifold, and a blade is rotatably installed on the top end of the rotating rod, and the blade and the air hole are located at the same horizontal plane.

[0016] 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 outside of the cover plate.

[0017] Preferably: the lifting assembly includes a straight rod, a screw, 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 is threadedly installed on the straight rod. The screw is parallel to the straight direction of the upper manifold, and the bottom end of the screw extends to the inside of the second gear, and the screw and the straight pipe are rotatably connected. The second gear is fixed to the bottom end of the screw, and a fixing ring is fixed to the inner side of the straight pipe. The second spring is fixed on the side of the fixing ring close to the annular pipe, and a baffle is installed on the end of the second spring. The side of the baffle is installed with a second rack meshing with the second gear.

[0018] The present invention also provides an online automatic detection method for atmospheric pollutants from fixed pollution sources, comprising the following steps:

[0019] Step 1: Install the air intake mechanism evenly around the circumference of the flue gas duct, and avoid sampling points at areas with unstable airflow, such as elbows and reducers. Then, vertically fix the side of the lower manifold to the flue gas duct. Finally, connect the circulation pipe to the flue gas duct to return the tested flue gas to the inside of the flue gas duct.

[0020] Step 2: The flow rate of the gas inside the flue gas duct is measured by the first wind speed sensor. Then, the controller is used to control the variable frequency fan to start and extract the flue gas. The extraction rate is the same as the flow rate of the flue gas inside the flue gas duct. The samples collected at multiple points enter the lower manifold for mixing.

[0021] 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 the flow rate inside the flue gas duct. The second concentration sensor is then used to accurately detect the concentration of pollutants in the flue gas. The detected flue gas then flows back into the flue gas duct.

[0022] Step 4: If the pollutant concentration is high and the dilution mechanism has a large intake volume during dilution, causing the gas flow rate detected by the second wind speed sensor to be greater than the intake flow rate, 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 flue gas enters;

[0023] 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.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides an online automatic detection device and method for atmospheric pollutants from fixed pollution sources. Multiple groups of air intake mechanisms are provided at the bottom of a lower manifold, and a first concentration sensor with a large range is provided on the side of the lower manifold. This allows for multi-point sampling during use, and preliminary detection of the concentration of the pollutant source in the flue gas. A dilution mechanism on the upper manifold is then used to inject a certain amount of clean gas into the flue gas, reducing the flue gas concentration by a certain proportion. The flue gas is finally discharged from the multiple detection tubes and detected using a second concentration sensor with a small range. This allows the device to not only perform multi-point sampling and measurement during use, but also to provide more representative data. Furthermore, the second concentration sensor with a small range ensures detection accuracy.

[0026] By evenly installing the air intake mechanism consisting of a conduit, a mounting sleeve, a flange, a mounting pipe, a sampling pipe, a hose, a slip ring, a first spring, a first rack, a first gear, and a 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.

[0027] The expansion mechanism composed of a cover plate, a sliding sleeve, a straight rod, a screw, 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

[0028] Figure 1 This 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;

[0029] Figure 2 This is a top-down cross-sectional view of the air intake mechanism distribution 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;

[0030] Figure 3 This is a diagram showing the initial state of the air 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;

[0031] 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;

[0032] 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;

[0033] Figure 6This is a diagram of a dilution 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;

[0034] 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 6 Enlarged view of point B in the middle;

[0035] Figure 8 This is a structural diagram of a sliding sleeve in a preferred embodiment of an online automatic detection device and method for atmospheric pollutants from a fixed pollution source of the present invention.

[0036] In the figure: 1. Lower manifold; 2. Variable frequency fan; 3. First concentration sensor;

[0037] 4. Inlet mechanism; 401. Conduit; 402. Mounting sleeve; 403. Flange; 404. Mounting tube; 405. Sampling tube; 406. Hose; 407. Slip ring; 408. First spring; 409. First rack; 410. First gear; 411. Casing;

[0038] 5. First wind speed sensor; 6. Controller;

[0039] 7. Upper manifold; 701. Rotating rod; 702. Blades;

[0040] 8. Dilution mechanism; 801. Mounting frame; 802. Filter cartridge; 803. Filter element; 804. Air pump; 805. Ring tube; 806. Straight tube; 807. Air hole; 808. First gas flow sensor;

[0041] 9. Detection tube; 10. Second wind speed sensor; 11. Second concentration sensor; 12. Circulation tube;

[0042] 13. Expansion mechanism; 1301. Cover plate; 1302. Sliding sleeve; 1303. Straight rod; 1304. Screw; 1305. Fixing ring; 1306. Second spring; 1307. Baffle; 1308. Second rack; 1309. Second gear;

[0043] 14. Second gas flow sensor. DETAILED DESCRIPTION

[0044] 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 described in further detail below with reference to embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0045] like Figures 1-8As shown, this 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 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, and the upper manifold A dilution mechanism 8 is provided on the flow tube 7. The top of the upper manifold 7 is evenly installed with detection tubes 9 of the same number as the air intake mechanism 4. A second concentration sensor 11 is installed on the top of the side of the detection tube 9. A second wind speed sensor 10 is provided on the side of the detection tube 9 and below the second concentration sensor 11. 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 manifold 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.

[0046] The overall working principle is: first, the air intake mechanism 4 is evenly installed in the circumferential direction of the flue gas duct, the angles between adjacent air intake mechanisms 4 are the same, and the sampling points avoid elbows, reducers and other areas with unstable airflow, then the side of the lower manifold 1 is vertically fixed to the flue gas duct, and finally the circulation pipe 12 is connected to the flue gas duct, and the flue gas after detection is returned to the inside of the flue gas duct. After the device is installed, when detection is required, the flow rate of the gas inside the flue gas duct is first measured by the first wind speed sensor 5, and then the controller 6 is used to control the start of the variable frequency fan 2 to extract the flue gas, and the extraction rate is the same as the flow rate of the flue gas inside the flue gas duct. The samples sampled at multiple points enter the interior of the lower manifold 1 for mixing, and the first concentration sensor 3 performs a rough inspection on the concentration of 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 interior of the upper manifold 7 to adjust the flue gas concentration A certain multiple of dilution is performed, and then the diluted gas enters the interior of 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, 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 of the dilution mechanism 8 is large during the dilution process, 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 × (Qflue + Qdilution) / Qflue. 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.

[0047] 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, and 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 tube 404 is rotatably installed on the end of the mounting sleeve 402 away from the flange 403. The sampling tube 405 is fixedly installed inside the mounting tube 404. 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. A rotating assembly for controlling the rotation of the mounting tube 404 is provided on the outside of the mounting sleeve 402. The maximum rotation angle of the mounting tube 404 is 90°.

[0048] Partial 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 for sealing. 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.

[0049] 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 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.

[0050] Partial 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 continues to be inserted, the first rack 409 slides in the straight direction relative to the mounting sleeve 402. The movement of the first rack 409 will drive 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.

[0051] In this embodiment, a protective shell 411 is symmetrically provided 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 .

[0052] 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.

[0053] 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 edge 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, and the air filter assembly is connected to the interior of the annular tube 805.

[0054] Local working principle: When the flue gas inside the upper manifold 7 needs to be diluted, the air filter component is used to filter the outside air to remove substances in the air that have the same components as the detected flue gas, 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 manifold 7 through the air hole 807 to dilute the flue gas.

[0055] 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, and 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, and 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 provided inside the straight pipe 806. The air pump 804 and the first gas flow sensor 808 are electrically connected to the controller 6 through a wire.

[0056] Partial working principle: Controller 6 controls the start-up of air pump 804, which extracts gas from the inside of filter cartridge 802, and the gas is filtered out of substances with the same components as the detected flue gas through filter element 803. Material of filter element 803: PTFE membrane with a pore size of 0.1μm is used, and the removal rate of target pollutants such as SO2 and NOx is ≥99.9%. After 1000 hours of continuous operation, the filtration efficiency is still ≥95%. Then, the gas is injected into the inside of the annular tube 805 through the straight tube 806. At the same time, the first gas flow sensor 808 detects the amount of injected gas to ensure the accurate ratio of flue gas to dilution gas.

[0057] 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 on the top of the rotating rod 701 . The blade 702 and the air hole 807 are located at the same horizontal plane.

[0058] Local working principle: After the diluted gas enters the interior of the upper manifold 7, the gas will blow on the blade 702 to control the rotation of the blade 702. The blade 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.

[0059] 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 outside of the cover plate 1301.

[0060] 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 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 the flow velocity v to increase, 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 more significantly, the pressure drops, and the exhaust rate decreases, thereby reducing the rate of flow out of the detection tube 9.

[0061] 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 to 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 second gear 1309. 9, and the screw 1304 is rotatably connected to the straight tube 806, the bottom end of the screw 1304 is fixed with a second gear 1309, the inner side of the straight tube 806 is fixed with a fixing ring 1305, the side of the fixing ring 1305 close to the annular tube 805 is fixed with a second spring 1306, the end of the second spring 1306 is installed with a baffle 1307, and the side of the baffle 1307 is installed with a second rack 1308 meshing with the second gear 1309.

[0062] Local working principle: When a large amount of dilution 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.

[0063] like Figures 1-8 As shown, this embodiment provides a method for online automatic detection of atmospheric pollutants from fixed pollution sources. The process is as follows:

[0064] Step 1: Install the air intake mechanism 4 evenly around the circumference of the flue gas duct, and avoid sampling points at areas with unstable airflow, such as elbows and reducers. Then, vertically fix the side of the lower manifold 1 to the flue gas duct. Finally, connect the circulation pipe 12 to the flue gas duct to return the tested flue gas to the interior of the flue gas duct.

[0065] Step 2: The flow rate of the gas inside the flue gas duct is measured by the first wind speed sensor 5. Then, the controller 6 controls the variable frequency fan 2 to start and extract the flue gas. The extraction rate is the same as the flow rate of the flue gas inside the flue gas duct. The samples collected at multiple points enter the lower manifold 1 for mixing.

[0066] 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. The detected flue gas then flows back into the flue gas duct.

[0067] Step 4: If the pollutant concentration is high and the dilution mechanism 8 has a large intake volume during dilution, causing the gas flow rate detected by the second wind speed sensor 10 to be greater than the intake flow rate, 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 of the flue gas entering;

[0068] 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.

[0069] The above is only a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which fall within the scope of protection 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 plurality of air flow sensors (14) arranged on the upper manifold (7). The top of the detection tube (9) is evenly installed with 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) 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 pipeline, the top of the upper confluence pipe (7) is provided with an expansion mechanism (13), 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; 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 bottom of the cover plate (1301) is fixed with a sliding sleeve (1302). The sliding sleeve (1302) is located inside the upper manifold (7) and is slidably connected to the upper manifold (7). The outer side of the cover plate (1301) is provided with a lifting assembly. 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 outside of the cover plate (1301). The screw rod (1304) is threadedly installed 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 inner side 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).

2. The online automatic detection device for atmospheric pollutants from stationary 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 (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 stationary pollution sources according to claim 2 is characterized by: 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 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) through 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 stationary 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 stationary 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). The outer side of the upper manifold (7) is equipped with an air filter assembly, and the air filter assembly is connected to the interior of the annular tube (805).

6. The online automatic detection device for atmospheric pollutants from stationary 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 the 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). The first gas flow sensor (808) is arranged inside the straight pipe (806). The air pump (804) and the first gas flow sensor (808) are electrically connected to the controller (6) via a wire.

7. The online automatic detection device for atmospheric pollutants from stationary pollution sources according to claim 6, characterized in that: 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 end of the rotating rod (701). The blade (702) and the air hole (807) are located at the same horizontal plane.

8. A method for online automatic detection of 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 7, characterized in that: The steps include: Step 1: Install the air intake mechanism (4) evenly in the circumferential direction of the flue gas duct, and avoid the sampling point in the unstable airflow area, 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 tested flue gas to the inside of the flue gas duct; Step 2: The flow rate of the gas inside the flue gas 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 extract the flue gas. The extraction rate is the same as the flow rate of the flue gas inside the flue gas duct. The samples collected at multiple points enter the lower manifold (1) for mixing. Step 3: The first concentration sensor (3) performs a rough inspection 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 interior of the upper manifold (7) to dilute the flue gas concentration by a certain multiple. The diluted gas then enters the interior of 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 the intake, the upper manifold (7) is expanded by 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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