A kind of extractable particulate matter monitor sample gas isokinetic system and its working method

Abstract

The application discloses an extractable particulate matter monitor sample gas equal-velocity system and a working method thereof, wherein a flue gas flow velocity measuring device and a Venturi flow differential pressure measuring device are connected with a control unit, the control unit can calculate the difference between the flue gas flow velocity and the target sample gas flow velocity in the Venturi flow differential pressure measuring device in real time; a second air inlet of a jet pump power device is connected with an air outlet of a target sample gas equal-velocity control device, the target sample gas equal-velocity control device can provide stable and adjustable airflow for the jet pump power device, a first air inlet of the jet pump power device is connected with an air outlet of the Venturi flow differential pressure measuring device, and the jet pump power device can provide stable and adjustable negative pressure for the Venturi flow differential pressure measuring device by using the airflow input by the target sample gas equal-velocity control device. The application can track and correct the flow velocity of the sampling target sample gas entering a measuring chamber and the flow velocity in a pollution source in real time, and ensure the accuracy of the target sample gas measurement result.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of on-line analysis extraction type ultra-low concentration particulate matter detector for flue gas pretreatment of stationary source flue gas emission, and particularly relates to a sample gas constant velocity system of extraction type particulate matter monitor and a working method thereof. BACKGROUND

[0002] At present, researchers in this field study the technical defects of the known technology of the existing measuring instrument device. Since the concentration distribution of flue dust in the flue is uneven, the sampling position is specified by the determination standard. In order to reduce the influence of the inertia force of particulate matter, the standard requires constant velocity sampling. The previous constant velocity sampling method is to use the predicted flow rate method. The gas flow rate, pressure, temperature, moisture content and other parameters at the sampling point are measured in advance, and the sampling nozzle diameter and sampling flow required for constant velocity sampling are calculated. The sampling instrument samples at the point according to the calculated flow. According to the regulations, ten sampling points are often required on each determination section, and the measurement and calculation process is quite cumbersome, so the sampling ratio sometimes lags behind for tens of minutes. The gas flow rate in the flue is constantly changing, and it is difficult to ensure constant velocity sampling using the predicted flow rate method, and the reliability of the determination result is not high. At present, this problem in the field has not been solved, and therefore there is an urgent need for a constant velocity sampling system that can solve the problem, improve the accuracy of the determination, and reduce the determination operation. SUMMARY

[0003] In order to solve the problems in the prior art, the purpose of the present application is to provide a sample gas constant velocity system of extraction type particulate matter monitor and a working method thereof. The present application can track and correct the flow rate of the target sample gas entering the measurement gas chamber in real time, and ensure the accuracy of the target sample gas measurement result.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] A sample gas constant velocity system of extraction type particulate matter monitor, comprising a flue gas flow rate measuring device, a control unit, a Venturi flow differential pressure measuring device, a jet pump power device and a target sample gas constant velocity control device, the flue gas flow rate measuring device and the Venturi flow differential pressure measuring device are connected with the control unit, the control unit can calculate the difference between the flue gas flow rate and the target sample gas flow rate in the Venturi flow differential pressure measuring device in real time; the jet pump power device is provided with a first gas inlet, a second gas inlet and a gas outlet, the second gas inlet of the jet pump power device is connected with the gas outlet of the target sample gas constant velocity control device, the target sample gas constant velocity control device can provide stable and adjustable airflow for the jet pump power device, the first gas inlet of the jet pump power device is connected with the gas outlet of the Venturi flow differential pressure measuring device, and the jet pump power device can provide stable and adjustable negative pressure for the Venturi flow differential pressure measuring device by using the airflow input by the target sample gas constant velocity control device.

[0006] Preferably, the jet pump power device comprises a jet pump power body and a power source nozzle, the jet pump power body is a structure with a cavity, the first inlet and the outlet of the jet pump power device are arranged on the jet pump power body and communicate with the inner cavity of the jet pump power body, the outlet of the power source nozzle is inserted into the inner cavity of the jet pump power body, the outlet of the power source nozzle extends to the outlet on the jet pump power body, a gap is left between the outlet of the power source nozzle and the outlet on the jet pump power body, the power source inlet of the power source nozzle serves as the second inlet of the jet pump power device, and the power source inlet is connected with the outlet of the target sample gas isokinetic control device.

[0007] Preferably, the outlet on the jet pump power body is in the shape of a circular truncated cone, the axis between the first inlet and the outlet on the jet pump power body is vertical, the outlet of the power source nozzle is in the shape of a cylinder, and the outlet of the power source nozzle is coaxially arranged with the outlet on the jet pump power body.

[0008] Preferably, the outlet of the power source nozzle extends into the inside of the large end of the outlet on the jet pump power body, and the outlet of the power source nozzle is provided with an outer chamfer.

[0009] Preferably, the target sample gas isokinetic control device comprises a precision flow regulating valve and a driving mechanism, the driving mechanism is connected with the control valve core of the precision flow regulating valve, the outlet of the precision flow regulating valve serves as the outlet of the target sample gas isokinetic control device, and the outlet of the precision flow regulating valve is connected with the second inlet of the jet pump power device.

[0010] Preferably, the driving mechanism comprises a target sample gas isokinetic control device base, a speed reducer and a shaft coupling, the speed reducer, the precision flow regulating valve and the stroke distance switch are all fixed on the target sample gas isokinetic control device base, the output shaft of the speed reducer is connected with the control valve core of the precision flow regulating valve through the shaft coupling, a stroke flange is fixedly sleeved on the shaft coupling, and stroke distance switches for detecting the position of the stroke flange are arranged on both sides of the stroke flange on the target sample gas isokinetic control device base.

[0011] Preferably, the sample gas isokinetic system of the extractable particulate matter monitor further comprises a compressed gas source and a pressure-adjusting water-liquid separator, the outlet of the compressed gas source is connected with the inlet of the pressure-adjusting water-liquid separator, and the outlet of the pressure-adjusting water-liquid separator is connected with the inlet of the target sample gas isokinetic control device.

[0012] Preferably, a buffer bottle is arranged on the pipeline connecting the outlet of the pressure-adjusting water-liquid separator with the inlet of the target sample gas isokinetic control device, and the buffer bottle is arranged in a heat preservation and heating device.

[0013] Preferably, the particle measuring device is installed on the pipeline connecting the first air inlet of the ejector power device with the air outlet of the Venturi flow differential pressure measuring device.

[0014] The working method of the extractable particle monitor gas sampling isokinetic system is as follows:

[0015] The flue gas flow rate in the pollution source is measured in real time by the flue gas flow rate measuring device.

[0016] The target gas isokinetic control device provides airflow for the ejector power device from the second air inlet of the ejector power device, the airflow provided by the target gas isokinetic control device for the ejector power device flows out from the air outlet of the ejector power device, and a negative pressure is formed in the inner cavity of the ejector power device; through the negative pressure, the target gas enters the inner cavity of the Venturi flow differential pressure measuring device from the target gas inlet of the Venturi flow differential pressure measuring device, then enters the inner cavity of the ejector power device from the first air inlet of the ejector power device, and then flows out from the air outlet of the ejector power device.

[0017] The flow rate of the target gas is measured in real time by the Venturi flow differential pressure measuring device.

[0018] The control unit compares the flue gas flow rate in the pollution source and the flow rate of the target gas in real time, and if the difference between the flue gas flow rate in the pollution source and the flow rate of the target gas is within a preset value range, it is considered that the flue gas flow rate in the pollution source and the flow rate of the target gas are isokinetic.

[0019] If the difference between the flue gas flow rate in the pollution source and the flow rate of the target gas is greater than the preset value, the flow rate of the target gas isokinetic control device for the ejector power device is adjusted until the difference between the flue gas flow rate in the pollution source and the flow rate of the target gas is within the preset value range.

[0020] The present application has the following advantages:

[0021] In the sample gas isokinetic system of the extractable particulate matter monitor, the flue gas flow rate can be measured in real time through the flue gas flow rate measuring device, the target sample gas flow rate can be measured in real time through the Venturi flow differential pressure measuring device, and the difference between the flue gas flow rate and the target sample gas flow rate in the Venturi flow differential pressure measuring device can be calculated in real time by using the control unit; the target sample gas isokinetic control device can provide stable and adjustable flow rate air flow for the jet pump power device, the air flow provided by the target sample gas isokinetic control device enters the second air inlet of the jet pump power device and then flows out from the air outlet of the jet pump power device, at this time, negative pressure is formed at the air outlet of the jet pump power device, by using the negative pressure, the jet pump power device can suck the target sample gas in the Venturi flow differential pressure measuring device from the first air inlet of the jet pump power device and spray it out from the air outlet of the jet pump power device, realizing the flow of the target sample gas in the Venturi flow differential pressure measuring device, thereby realizing the purpose of measuring the target sample gas flow rate in real time by the Venturi flow differential pressure measuring device, and since the negative pressure in the jet pump power device can be adjusted by the target sample gas isokinetic control device, the adjustable target sample gas flow rate can be realized, when the difference between the flue gas flow rate and the target sample gas flow rate in the pollution source is within the preset value range, it is considered that the flue gas flow rate and the target sample gas flow rate in the pollution source are isokinetic, and in summary, the present application can realize real-time tracking and calibration of the flow rate of the sample target sample gas entering the measuring chamber and the flow rate in the pollution source emission, thereby ensuring the accuracy of the target sample gas measurement result. BRIEF DESCRIPTION OF DRAWINGS

[0022] The following drawings are further detailed description of the present application.

[0023] Figure 1 is a structural schematic diagram of the sample gas isokinetic system of the extractable particulate matter monitor of the present application.

[0024] Figure 2 is Figure 1 is an enlarged sectional view of the structure of serial number 1A.

[0025] Figure 3 is Figure 1 is an enlarged sectional view of the structure of serial number 1B.

[0026] Figure 4 is Figure 1 is an enlarged sectional view of the structure of serial number 1C.

[0027] Figure 5 is a front view of the target sample gas isokinetic control device of the present application.

[0028] In the figure, 1-pollution source emission, 2-Pitot tube, 3-flange cover, 4-pollution source flow rate positive pressure sampling tube, 5-pollution source flow rate negative pressure sampling tube, 6-isokinetic measurement circuit board, 7-external input signal, 8-data cable, 9-main control circuit board, 10-target sample gas inlet, 11-venturi flow differential pressure measuring device, 12-target sample gas positive pressure sampling tube, 13-target sample gas negative pressure sampling tube, 14-optical measurement gas chamber, 15-thermostatic heating sheet, 16-jet pump power device, 17-target sample gas isokinetic control device, 18-buffer bottle, 19-pressure regulating water liquid separator, 20-compressed gas source, 21-target sample gas exhaust port, 22-venturi flow differential pressure measuring body, 23-target sample gas pressure sampling nozzle, 24-first sealing ring, 25-jet pump power body, 26-second sealing ring, 27-power gas source nozzle, 28-third sealing ring, 29-power gas source sealing cover, 30-fourth sealing ring, 31-power gas source inlet, 32-target sample gas isokinetic control device base, 33-deceleration motor, 34-stroke flange, 37-precision flow regulating valve, 38-stroke distance switch. DETAILED DESCRIPTION

[0029] The application will be further described below in conjunction with the drawings and examples.

[0030] Referring to Figures 1-5 , the sample gas isokinetic system of the extractable particulate matter monitor includes a flue gas flow rate measuring device, a control unit, a venturi flow differential pressure measuring device 11, a jet pump power device 16 and a target sample gas isokinetic control device 17. The flue gas flow rate measuring device and the venturi flow differential pressure measuring device 11 are connected with the control unit. The control unit can calculate the difference between the flue gas flow rate and the target sample gas flow rate in the venturi flow differential pressure measuring device 11 in real time. The jet pump power device 16 is provided with a first gas inlet, a second gas inlet and a gas outlet. The second gas inlet of the jet pump power device 16 is connected with the gas outlet of the target sample gas isokinetic control device 17. The target sample gas isokinetic control device 17 can provide stable and adjustable airflow for the jet pump power device 16. The first gas inlet of the jet pump power device 16 is connected with the gas outlet of the venturi flow differential pressure measuring device 11. The jet pump power device 16 can provide stable and adjustable negative pressure for the venturi flow differential pressure measuring device 11 by using the airflow input by the target sample gas isokinetic control device 17.

[0031] Referring to Figure 1 , Figures 3-5 , the working principle of the sample gas isokinetic system of the extractable particulate matter monitor as described above is as follows:

[0032] The flue gas flow rate in the pollution source is measured in real time by the flue gas flow rate measuring device;

[0033] The target sample gas equal velocity control device 17 is connected with a compressed air source, and the target sample gas equal velocity control device 17 provides the jet pump power device 16 with air flow from the second air inlet of the jet pump power device 16. The air flow provided by the target sample gas equal velocity control device 17 flows out from the air outlet of the jet pump power device 16, and a negative pressure is formed in the inner cavity of the jet pump power device 16. Through the negative pressure, the target sample gas enters the inner cavity of the Venturi flow differential pressure measuring device 11 from the target sample gas inlet 10 of the Venturi flow differential pressure measuring device 11, and then enters the inner cavity of the jet pump power device 16 from the first air inlet of the jet pump power device 16, and then flows out from the air outlet of the jet pump power device 16.

[0034] The flow velocity of the target sample gas is measured in real time by the Venturi flow differential pressure measuring device 11.

[0035] The control unit compares the flow velocity of the flue gas in the pollution source and the flow velocity of the target sample gas in real time. If the difference between the flow velocity of the flue gas in the pollution source and the flow velocity of the target sample gas is within a preset value range, it is considered that the flow velocity of the flue gas in the pollution source and the flow velocity of the target sample gas are equal.

[0036] If the difference between the flow velocity of the flue gas in the pollution source and the flow velocity of the target sample gas is greater than the preset value, the flow of the target sample gas equal velocity control device 17 to the jet pump power device 16 is adjusted until the difference between the flow velocity of the flue gas in the pollution source and the flow velocity of the target sample gas is within the preset value range.

[0037] Referring to Figure 3The jet pump power device 16 comprises a jet pump power body 25 and a power gas source nozzle 27. The jet pump power body 25 is a structure with a cavity. The first inlet and the outlet of the jet pump power device 16 are arranged on the jet pump power body 25 and communicate with the inner cavity of the jet pump power body 25. The outlet of the power gas source nozzle 27 is inserted into the inner cavity of the jet pump power body 25. The outlet of the power gas source nozzle 27 extends to the outlet on the jet pump power body 25. There is a gap between the outlet of the power gas source nozzle 27 and the outlet on the jet pump power body 25. The power gas source inlet 31 of the power gas source nozzle 27 serves as the second inlet of the jet pump power device 16 and is connected with the outlet of the target sample gas constant velocity control device 17. The compressed air provided by the target sample gas constant velocity control device 17 enters the power gas source inlet 31 and is sprayed from the outlet of the power gas source nozzle 27. The compressed air sprayed from the outlet of the power gas source nozzle 27 continues to flow to the left and is sprayed from the outlet on the left side of the jet pump power body 25. Since there is a gap between the outlet of the power gas source nozzle 27 and the outlet on the jet pump power body 25, a negative pressure is formed in the inner cavity of the jet pump power body 25. Due to the negative pressure, the target sample gas in the Venturi flow differential pressure measuring device 11 is sucked into the inner cavity of the jet pump power body 25 from the first inlet (the upper port) of the jet pump power body 25, passes through the gap between the outlet of the power gas source nozzle 27 and the outlet on the jet pump power body 25, and finally flows out from the outlet on the jet pump power body 25, thereby realizing the flow of the target sample gas. By controlling the flow of the compressed air provided by the target sample gas constant velocity control device 17, the size of the negative pressure in the jet pump power body 25 can be controlled, and the flow rate of the target sample gas in the Venturi flow differential pressure measuring device 11 can be adjusted.

[0038] As Figure 3As shown, the gas outlet on the jet pump power body 25 can be provided in a circular truncated cone shape, the corresponding cone angle of the circular truncated cone being 30°-60°, the axis before the first gas inlet and the gas outlet on the jet pump power body 25 is perpendicular, the outlet of the power gas source nozzle 27 is in a cylindrical shape, and the outlet of the power gas source nozzle 27 is coaxially arranged with the gas outlet on the jet pump power body 25. In this structure, the circular truncated cone-shaped gas outlet is beneficial to ensure that the gas flow velocity of the gas outlet of the jet pump power body 25 remains stable, thereby ensuring the stable flow rate of the target sample gas. The outlet of the power gas source nozzle 27 extends into the inside of the large end of the gas outlet on the jet pump power body 25, which can prevent the gas flow of the outlet of the power gas source nozzle 27 from directly flowing back to the Venturi flow differential pressure measuring device 11 from the first gas inlet of the jet pump power body 25, and can also reduce the disturbance to the gas flow of the first gas inlet of the jet pump power body 25 as much as possible, thereby ensuring the stability of the flow rate of the target sample gas. The outlet of the power gas source nozzle 27 is provided with an outer chamfer, which can prevent the gas flow of the outlet of the power gas source nozzle 27 from being violently entrained at the outlet of the power gas source nozzle 27, thereby reducing the influence on the smoothness and stability as much as possible, and ensuring the stability of the flow rate of the target sample gas.

[0039] Referring to Figure 4 and Figure 5 , the target sample gas constant velocity control device 17 comprises a precision flow regulating valve 37 and a driving mechanism, the driving mechanism is connected with the control valve core of the precision flow regulating valve 37, the outlet of the precision flow regulating valve 37 serves as the gas outlet of the target sample gas constant velocity control device 17, the gas outlet of the precision flow regulating valve 37 is connected with the second gas inlet of the jet pump power device 16, and the control valve core of the precision flow regulating valve 37 is driven by the driving mechanism to move along the axial direction, thereby realizing the regulation of the gas flow entering the jet pump power device 16.

[0040] Referring to Figure 4 and Figure 5 , the driving mechanism of the present application comprises a target sample gas constant velocity control device base 32, a speed reducer motor 33 and a shaft coupling, the speed reducer motor 33, the precision flow regulating valve 37 and the stroke distance switch 38 are all fixed on the target sample gas constant velocity control device base 32, the output shaft of the speed reducer motor 33 is connected with the control valve core of the precision flow regulating valve 37 through the shaft coupling, the shaft coupling is variable in length in the axial direction (i.e. the length can be elongated or shortened), a stroke flange 34 is fixedly sleeved on the shaft coupling, and the stroke distance switch 38 for detecting the position of the stroke flange 34 is arranged on both sides of the stroke flange 34 on the target sample gas constant velocity control device base 32. When regulating the flow of the precision flow regulating valve 37, the speed reducer motor 33 drives the control valve core of the precision flow regulating valve 37 to rotate through the shaft coupling, the control valve core and the valve body are threadedly connected, and the control valve core can move left and right along the valve body after rotating (see Figure 4), the left and right movement of the control valve core can realize the size of the outlet gas flow of the precision flow regulating valve 37, so as to realize the flow regulation. By setting the stroke flange 34 and the stroke distance switch 38, the stroke flange 34 will move left and right with the movement of the control valve core during the rotation of the shaft coupling, and the speed reducer motor 33 can be controlled to stop rotating when the stroke flange 34 is located at the detection position of the stroke distance switch 38, so as to prevent the control valve core from being damaged by over-regulation.

[0041] The sample gas isodense system of the extractable particulate matter monitor can also be equipped with a compressed gas source 20 and a pressure-adjusting water-liquid separator 19, the outlet of the compressed gas source 20 is connected with the gas inlet of the pressure-adjusting water-liquid separator 19, and the gas outlet of the pressure-adjusting water-liquid separator 19 is connected with the gas inlet of the target sample gas isodense control device 17. The compressed air in the compressed gas source 20 enters the target sample gas isodense control device 17 after being separated from water by the pressure-adjusting water-liquid separator 19, so as to prevent the influence of water vapor on the stability of the target sample gas flow rate. Meanwhile, a buffer bottle 18 can be arranged on the pipeline connecting the gas outlet of the pressure-adjusting water-liquid separator 19 with the gas inlet of the target sample gas isodense control device 17, and the buffer bottle 18 is arranged in a heat preservation and heating device. The buffer bottle 18 as a gas buffer helps to stabilize the outlet compressed air flow rate of the target sample gas isodense control device 17, and can also heat and preserve the gas in the buffer bottle 18 by the heat preservation and heating device, so as to prevent the external temperature field from greatly influencing the stability of the gas flow.

[0042] In the present application, the particulate matter measuring device (such as the optical measuring chamber 14) can be installed on the pipeline connecting the first gas inlet of the jet pump power device 16 with the gas outlet of the Venturi flow differential pressure measuring device 11, so as to detect the particulate matter in the target sample gas.

[0043] Embodiment

[0044] Reference Figures 1-5 The sample gas isodense system of the extractable particulate matter monitor includes a Pitot tube 2, a flange sleeve 3, a pollution source flow rate positive pressure sampling pipe 4, a pollution source flow rate negative pressure sampling pipe 5, an isodense measuring circuit board 6, a data wire 8, a main control circuit board 9, a target sample gas positive pressure sampling pipe 12, a target sample gas negative pressure sampling pipe 13, a Venturi flow differential pressure measuring device 11, a jet pump power device 16, a target sample gas isodense control device 17, a buffer bottle 18, a pressure-adjusting water-liquid separator 19 and a compressed gas source 20.

[0045] Wherein, the pitot tube 2, the flange sleeve 3, the pollution source flow rate positive pressure sampling pipe 4, the pollution source flow rate negative pressure sampling pipe 5, the constant speed measurement circuit board 6 constitute the flue gas flow rate measuring device of the application, of course the flue gas flow rate measuring device of the application can also adopt other structures, the application does not make specific limitation. The pitot tube 2 and the flange sleeve 3 are fastened integrally, the pitot tube 2 is connected with the constant speed measurement circuit board 6 through the pollution source flow rate positive pressure sampling pipe 4 and the pollution source flow rate negative pressure sampling pipe 5, the constant speed measurement circuit board 6 can obtain the flow rate of flue gas in the pollution source discharge 1 through the flue gas introduced by the pollution source flow rate positive pressure sampling pipe 4 and the pollution source flow rate negative pressure sampling pipe 5. The venturi flow differential pressure measuring device 11 and the main control circuit board 9 are connected through the target sample gas positive pressure sampling pipe 12 and the target sample gas negative pressure sampling pipe 13. The main control circuit board 9 and the constant speed measurement circuit board 6 are connected through the data wire harness 8. When the equipment does not need the pitot tube 2, the external input signal 7 is connected with the constant speed measurement circuit board 6.

[0046] In the embodiment, the optical measurement gas chamber 14 is used as a particulate matter monitoring device, which is installed on the pipeline between the venturi flow differential pressure measuring device 11 and the first inlet of the jet pump power device 16. The venturi flow differential pressure measuring device 11, the optical measurement gas chamber 14 and the jet pump power device 16 are fastened integrally. The jet pump power device 16, the target sample gas constant speed control device 17, the heated gas storage bottle 18, the pressure regulating water liquid separator 19 and the compressed gas source 20 are connected in series through pipelines.

[0047] The compressed gas source 20 generates a power gas source, which is adjusted to a constant pressure gas source through the pressure regulating water liquid separator 19, enters the jet pump power device 16 through the heated gas storage bottle 18 and the target sample gas constant speed control device 17 to generate a power gas source, and the power gas source makes the target sample gas enter the jet pump power device 16 through the target sample gas inlet 10, the venturi flow differential pressure measuring device 11 and the optical measurement gas chamber 14, while the target sample gas exhaust port 21 discharges.

[0048] Referring to Figure 2The structure of the Venturi flow differential pressure measuring device 11 includes a Venturi flow differential pressure measuring body 22, a target sample gas differential pressure sampling nozzle 23, and a first sealing ring 24. The internal structure of the Venturi flow differential pressure measuring body 22 is stepped, with the positive pressure aperture multiple greater than the negative pressure aperture, forming a target sample gas differential pressure. The target sample gas inlet 10 enters the Venturi flow differential pressure measuring device 11 to form a target sample gas differential pressure, which is input into the main control circuit board 9 through the target sample gas pressure sampling nozzle 23, the target sample gas positive pressure sampling tube 12, and the target sample gas negative pressure sampling tube 13, and the target sample gas flow rate value between 0-40 m / s is calculated. The target sample gas positive pressure sampling tube 12 is connected to the upper target sample gas differential pressure sampling nozzle 23, and the target sample gas negative pressure sampling tube 13 is connected to the lower target sample gas differential pressure sampling nozzle 23. The upper port of the Venturi flow differential pressure measuring device 11 is the target sample gas inlet 10, and the lower port of the Venturi flow differential pressure measuring device 11 is in communication with the gas inlet of the optical measurement gas chamber 14.

[0049] Referring to Figure 3 The jet pump power device 16 includes a jet pump power body 25 and a power gas source nozzle 27. The power gas source nozzle 27 includes a power gas source inlet 31, a gas chamber, and an outlet tube. The gas chamber is integrally formed with the jet pump power body 25. The outlet tube of the power gas source nozzle 27 is a circular tube with a chamfered end. The outlet tube of the power gas source nozzle 27 is sealed and connected to the jet pump power body 25 through a third sealing ring 28 and is in communication with the gas chamber. The power gas source inlet 31 is in communication with the gas chamber. A power gas source sealing cover 29 is installed on the gas chamber through a fourth sealing ring 30. The upper port of the jet pump power body 25 is in communication with the gas outlet of the optical measurement gas chamber 14. The upper port of the jet pump power body 25 is provided with a second sealing ring 26 for sealed connection. The conical angle of the circular cone corresponding to the gas outlet of the jet pump power body 25 is 45°.

[0050] The target sample gas constant speed control device 17 includes a target sample gas constant speed control device base 32, a speed reduction motor 33, a stroke flange 34, a precision flow regulating valve 37, and a stroke distance switch 38. Referring to Figure 4 The speed reduction motor 33, the stroke flange 34, and the precision flow regulating valve 37 are coaxially fastened to the target sample gas constant speed control device base 32 through locking screws. The stroke flange 34 and the precision flow regulating valve 37 form an axial transmission through the speed reduction motor 33, which can adjust the gas source flow size of the precision flow regulating valve 37. The stroke distance switches 38 are distributed on the left and right sides of the stroke flange 34. The rotation stroke distance of the stroke flange 34 is 0-15 mm. The stroke distance switches 38 are installed at the minimum stroke and maximum stroke positions of the stroke flange. The distance between the stroke distance switches 38 and the stroke flange is 2.5-3 mm, which ensures that the stroke flange 38 stops rotating immediately when it reaches the minimum or maximum value.

[0051] The constant temperature heating sheet 15 is fastened with the optical measuring gas chamber 14. The constant temperature heating sheet 15 is used for heating the target sample gas at the entrance of the optical measuring gas chamber 14. The constant temperature heating sheet 15 can keep the temperature of the target sample gas at 80-100℃, and keep the target sample gas entering the optical measuring gas chamber 14 as dry target sample gas.

[0052] The isokinetic system of the extractable particulate matter monitor of the embodiment can ensure that the flow rate of the target sample gas entering the optical measuring gas chamber 14 is equal to the flow rate in the pollution source discharge 1, so as to realize the real-time isokinetic effect of the target sample gas sampling, and ensure the accuracy of the particulate matter concentration measurement. The deficiencies of the devices in the industry are solved.

[0053] The working method of the isokinetic system of the extractable particulate matter monitor of the embodiment includes the following processes:

[0054] The compressed gas source 20 generates a power gas source, a constant pressure gas source is discharged through the pressure regulating water separator 19, and a power gas source is generated in the jet pump power device 16 through the heated gas storage bottle 18 and the target sample gas isokinetic control device 17. The power gas source passes through the jet pump power device 16 to make the target sample gas pass through the target sample gas inlet 10, the venturi flow differential pressure measuring device 11, and the optical measuring gas chamber 14 into the jet pump power device 16, and at the same time, the target sample gas exhaust port 21 is discharged.

[0055] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , in the isokinetic system of the extractable particulate matter monitor of the embodiment, the isokinetic measuring circuit board 6 measures the pollution source flow rate value between 0-40m / s in the pollution source discharge through the pitot tube 2, the pollution source flow rate positive pressure sampling tube 4, and the pollution source flow rate negative pressure sampling tube 5. The pollution source flow rate value between 0-40m / s in the pollution source discharge is measured as a raw fixed value, and the data cable 8 is input into the main control circuit board 9.

[0056] Target sample gas enters the Venturi flow differential pressure measuring device 11 through the target sample gas inlet 10, and the main control circuit board 9 obtains the target sample gas flow rate value between 0-40 m / s through the Venturi flow differential pressure measuring device 11, the target sample gas positive pressure sampling pipe 12, and the target sample gas negative pressure sampling pipe 13. The main control circuit board 9 compares the data by taking the pollution source flow rate value between 0-40 m / s in the pollution source emission received as the original fixed value and the target sample gas flow rate value between 0-40 m / s measured by the Venturi flow differential pressure measuring device 11, and the error range is 0.5-1 m / s. When the target sample gas flow rate value between 0-40 m / s measured by the Venturi flow differential pressure measuring device 11 has deviation, the target sample gas constant velocity control device 17 is used to adjust the size of the power source of the jet pump power device 16. The target sample gas flow rate value between 0-40 m / s measured by the Venturi flow differential pressure measuring device 11 is equal to the pollution source flow rate value between 0-40 m / s in the pollution source emission, and the error range is 0.5-1 m / s. The pollution source flow rate value between 0-40 m / s in the pollution source emission is equal to the target sample gas flow rate value between 0-40 m / s measured by the Venturi flow differential pressure measuring device 11 when the target sample gas enters the optical measuring gas chamber 14, and the error range is 0.5-1 m / s, that is, the flow rate value of the equipment is in a constant velocity state.

Claims

1. A draw-ee particulate matter monitor sample gas isokinetic system characterized by, The device comprises a flue gas flow rate measuring device, a control unit, a Venturi flow differential pressure measuring device (11), a jet pump power device (16) and a target sample gas constant speed control device (17). The flue gas flow rate measuring device and the Venturi flow differential pressure measuring device (11) are connected with the control unit, and the control unit can calculate the difference between the flue gas flow rate and the target sample gas flow rate in the Venturi flow differential pressure measuring device (11) in real time. The jet pump power device (16) is provided with a first air inlet, a second air inlet and an air outlet. The second air inlet of the jet pump power device (16) is connected with the air outlet of the target sample gas constant speed control device (17). The target sample gas constant speed control device (17) can provide stable and adjustable airflow for the jet pump power device (16). The first air inlet of the jet pump power device (16) is connected with the air outlet of the Venturi flow differential pressure measuring device (11). The jet pump power device (16) can provide stable and adjustable negative pressure for the Venturi flow differential pressure measuring device (11) by using the airflow input by the target sample gas constant speed control device (17). The jet pump power device (16) comprises a jet pump power body (25) and a power gas source nozzle (27). The jet pump power body (25) is a structure with a cavity. The first air inlet and the air outlet of the jet pump power device (16) are arranged on the jet pump power body (25) and are in communication with the inner cavity of the jet pump power body (25). The outlet of the power gas source nozzle (27) is inserted into the inner cavity of the jet pump power body (25). The outlet of the power gas source nozzle (27) extends to the air outlet on the jet pump power body (25). There is a gap between the outlet of the power gas source nozzle (27) and the air outlet on the jet pump power body (25). The power gas source inlet (31) of the power gas source nozzle (27) serves as the second air inlet of the jet pump power device (16). The power gas source inlet (31) is connected with the air outlet of the target sample gas constant speed control device (17). A particulate matter measuring device is installed on the pipeline connecting the first air inlet of the jet pump power device (16) with the air outlet of the Venturi flow differential pressure measuring device (11).

2. The extractable particulate monitor constant velocity sample gas system of claim 1, wherein, The air outlet on the jet pump power body (25) is in the shape of a circular truncated cone. The axis before the first air inlet and the air outlet on the jet pump power body (25) is perpendicular. The outlet of the power gas source nozzle (27) is in the shape of a cylinder. The outlet of the power gas source nozzle (27) is coaxially arranged with the air outlet on the jet pump power body (25).

3. The extractable particulate monitor isokinetic system of claim 2, wherein, The outlet of the power gas source nozzle (27) extends into the interior of the large end of the air outlet on the jet pump power body (25). The outlet of the power gas source nozzle (27) is provided with an outer chamfer.

4. The extractable particulate monitor isokinetic system of claim 1, wherein, The target sample gas constant speed control device (17) comprises a precision flow regulating valve (37) and a driving mechanism. The driving mechanism is connected with the control valve core of the precision flow regulating valve (37). The outlet of the precision flow regulating valve (37) serves as the air outlet of the target sample gas constant speed control device (17). The air outlet of the precision flow regulating valve (37) is connected with the second air inlet of the jet pump power device (16).

5. A draw-out particle monitor isokinetic system according to claim 4, characterized in that, The driving mechanism comprises a target sample gas constant velocity control device base (32), a speed reducer motor (33) and a shaft coupling, the speed reducer motor (33), a precision flow regulating valve (37) and a stroke distance switch (38) are all fixed on the target sample gas constant velocity control device base (32), the output shaft of the speed reducer motor (33) is connected with the control valve core of the precision flow regulating valve (37) through the shaft coupling, a stroke flange (34) is fixedly sleeved on the shaft coupling, and the target sample gas constant velocity control device base (32) is provided with the stroke distance switch (38) for detecting the position of the stroke flange (34) on the two sides of the stroke flange (34).

6. The extractable particulate monitor isokinetic system of claim 1, wherein, The device further comprises a compressed gas source (20) and a pressure regulating water liquid separator (19), the outlet of the compressed gas source (20) is connected with the gas inlet of the pressure regulating water liquid separator (19), and the gas outlet of the pressure regulating water liquid separator (19) is connected with the gas inlet of the target sample gas constant velocity control device (17).

7. A draw-out particle monitor isokinetic system according to claim 6, wherein, A buffer bottle (18) is arranged on the pipeline connecting the gas outlet of the pressure regulating water liquid separator (19) with the gas inlet of the target sample gas constant velocity control device (17), and the buffer bottle (18) is arranged in a heat preservation and heating device.

8. The method of claim 1-7, wherein the method further comprises: The device comprises the following processes: Real-time measurement of the flow velocity of the flue gas in the pollution source is performed through a flue gas flow velocity measuring device; The target sample gas constant velocity control device (17) provides the airflow for the jet pump power device (16) from the second gas inlet of the jet pump power device (16), the airflow provided by the target sample gas constant velocity control device (17) for the jet pump power device (16) flows out from the gas outlet of the jet pump power device (16), and a negative pressure is formed in the inner cavity of the jet pump power device (16); through the negative pressure, the target sample gas enters the inner cavity of the Venturi flow differential pressure measuring device (11) from the target sample gas inlet (10) of the Venturi flow differential pressure measuring device (11), and then enters the inner cavity of the jet pump power device (16) from the first gas inlet of the jet pump power device (16), and then flows out from the gas outlet of the jet pump power device (16); Real-time measurement of the flow velocity of the target sample gas is performed through the Venturi flow differential pressure measuring device (11); The control unit compares the flow velocities of the flue gas in the pollution source and the target sample gas in real time, and if the difference between the flow velocities of the flue gas in the pollution source and the target sample gas is within a preset value range, it is considered that the flow velocities of the flue gas in the pollution source and the target sample gas are constant; If the difference between the flow velocities of the flue gas in the pollution source and the target sample gas is greater than the preset value, the flow of the target sample gas constant velocity control device (17) for the jet pump power device (16) is adjusted until the difference between the flow velocities of the flue gas in the pollution source and the target sample gas is within the preset value range; The adjustment process of the flow velocity of the target sample gas comprises: The compressed air provided by the target sample gas constant velocity control device (17) enters through the power gas source inlet (31) and is sprayed out from the outlet of the power gas source nozzle (27). The compressed air sprayed out from the outlet of the power gas source nozzle (27) continues to flow to the left and is sprayed out from the gas outlet on the left side of the jet pump power body (25). At this time, a negative pressure is formed in the inner cavity of the jet pump power body (25). Through the negative pressure, the target sample gas in the Venturi flow differential pressure measuring device (11) is sucked into the inner cavity of the jet pump power body (25) from the first gas inlet of the jet pump power body (25) and flows out from the gap between the outlet of the power gas source nozzle (27) and the gas outlet on the jet pump power body (25) and finally from the gas outlet on the jet pump power body (25), realizing the flow of the target sample gas. By controlling the flow of the compressed air provided by the target sample gas constant velocity control device (17), the size of the negative pressure in the jet pump power body (25) can be controlled, and the flow rate of the target sample gas in the Venturi flow differential pressure measuring device (11) can be adjusted.

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