A pipeline cross-section gas velocity and concentration testing system

Abstract

The present application relates to a kind of pipeline cross section gas velocity, concentration test system, including the symmetric insertion flue in n probe rod testing device, each probe rod testing device is uniformly arranged with m test points along the depth direction of pipeline cross section;Probe rod testing device includes probe rod assembly, measurement cavity component, heat preservation shell, measurement and control module and box;Probe rod assembly includes base section and m-1 lengthening section, base section and lengthening section all include pitot tube, connecting piece, outer sleeve, pressure transmission pipe and gas concentration transmission pipe;Measurement cavity component includes measurement cavity, jet component and gas concentration sensor.In the present application, the gas velocity field and concentration field of multiple test points can be simultaneously tested in real time online, with high testing accuracy, and without the need to lay a large number of pipelines, which can be assembled according to the site arrangement of test points, reducing the difficulty of construction, maintenance and maintenance.

Description

Technical Field

[0001] This invention relates to a testing system, specifically a gas velocity and concentration testing system for a pipeline cross-section, belonging to the field of environmental monitoring technology. Background Technology

[0002] Flue gas emissions from power plant boilers, industrial kilns, and heating boilers are major sources of air pollution in most parts of my country, with sulfur dioxide (SO2) and nitrogen oxides (NOx) being the primary pollutants. To monitor and control flue gas pollutant emissions, it is necessary to accurately test the concentration and velocity field distributions at different measuring points within the flue gas duct cross-section. Based on the test data, the flue gas flow field within the duct should then be optimized. Therefore, the test data from each measuring point within the flue gas duct is crucial for the monitoring and control of flue gas pollutants.

[0003] Traditional continuous flue gas composition monitoring systems can only measure at a single point. Due to the large size of the flue and the uneven distribution of the flow field, it is difficult to ensure that the true average concentration of each component in the flue gas is reflected under all operating conditions. This results in a certain deviation between the measured data and the actual data, and the sampling points are not representative.

[0004] Existing methods for measuring gas velocity and concentration in flue gas duct sections mostly employ multi-point sampling and sequential measurement to achieve grid-like measurements of the flue gas duct section. For example, solenoid valves are installed on the sampling pipelines at each measuring point, and measurements are taken sequentially by controlling the opening and closing of each solenoid valve. However, this method usually lags behind the rapid changes in boiler operation, and cannot obtain accurate flue gas duct section parameters. Velocity and concentration measurements cannot be performed simultaneously. Furthermore, this method often only arranges measuring points along the circumference of the flue gas duct, while the gas concentration and velocity vary greatly from the center point to the edge of the flue gas duct. Therefore, the measurement results obtained by this method are not representative and cannot provide accurate data for subsequent data analysis, monitoring, and control, making it difficult to meet the requirements for accurate measurement of flue gas emissions.

[0005] Another method is to achieve multi-point measurement by using a matrix grid measurement along the depth direction and circumferential direction of the flue. For example, multiple sampling tubes are arranged along different depth directions. Then, all sampling tubes are led out of the flue gas through flue gas transmission pipelines to the flue gas analyzer for concentration analysis. Then, the flue gas enters the gas pressure sensor through the pressure transmission pipeline to detect the pressure information of the flue gas at each sampling point. Each sampling point is equipped with a separate sampling pipeline, and each sampling pipeline is further equipped with a pressure transmission pipeline and a flue gas transmission pipeline. For example, if 3 sampling points are arranged along the depth direction and 4 groups are arranged along the width direction of the flue cross section, then 3x4 sampling pipelines are required, as well as 3x4x2 pressure transmission pipelines and flue gas transmission pipelines. When the flue size is large, more sampling pipelines need to be arranged. The pipeline layout is very complex, the data transmission path is long, which not only makes maintenance and repair inconvenient but also increases the testing time. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a gas velocity and concentration testing system for pipeline cross-sections. The gas velocity and concentration fields at multiple measuring points can be tested simultaneously and in real time online with high accuracy. Moreover, it does not require the laying of a large number of pipelines and can be assembled on-site according to the arrangement of measuring points, reducing the difficulty of construction, maintenance and repair.

[0007] A gas velocity and concentration testing system for a pipe section includes n probe testing devices symmetrically inserted into a flue, n≥4, each probe testing device having m test points evenly distributed along the depth direction of the pipe section, m≥2, and the m×n test points are arranged in a grid-like distribution on the pipe measurement section. The probe testing device includes a probe assembly, a measuring cavity assembly, an insulation shell, a measurement and control module, and a housing. The probe assembly is installed outside the housing and connected to the measuring cavity assembly. The measuring cavity assembly and the measurement and control module are both located inside the housing, and the insulation shell is installed outside the measuring cavity assembly. The probe assembly includes a base section and m-1 extension sections. Both the base section and the extension sections include a Pitot tube, a connector, an outer sleeve, a pressure transmission tube, and a gas concentration transmission tube. The Pitot tube is fixed between the two outer sleeves by the connector. The Pitot tube is provided with two pressure measuring ports and a gas inlet. The opening direction of the two pressure measuring ports is arranged back and forth along the flue gas flow direction. The pressure transmission tube and the gas concentration transmission tube are both installed inside the outer sleeve. The measurement chamber assembly includes a measurement chamber, a jet assembly, and a gas concentration sensor. The measurement chamber has a pressure test chamber connected to the pressure transmission pipes of each measurement point and a gas concentration test chamber connected to the gas concentration transmission pipes of each measurement point. The pressure difference of each measurement point is sequentially led to the measurement and control module through the two pressure test ports on the Pitot tube, the pressure transmission pipe, and the pressure test chamber. The gas at each measurement point is sequentially led to the measurement and control module through the gas inlet on the Pitot tube, the gas concentration transmission pipe, the gas concentration test chamber, and the gas concentration sensor. The negative pressure channel of the jet assembly is connected to each gas concentration test chamber to form a negative pressure to introduce gas at each measurement point.

[0008] Furthermore, each connector has several through holes, which are used to connect the pressure measuring port on the pitot tube to the pressure transmission tube and the gas inlet to the gas concentration transmission tube, respectively.

[0009] Furthermore, the measurement and control module includes a differential pressure sensor module, a gas concentration analysis module, a main controller module, a power supply module, and a wireless transmission module. The differential pressure at each measuring point is simultaneously transmitted to the differential pressure sensor module through the pressure measuring port on each pitot tube, and the gas concentration at each measuring point is simultaneously transmitted to the gas concentration analysis module through the gas inlet on each pitot tube. The differential pressure sensor module and the gas concentration analysis module are respectively connected to the main controller module. The main controller module sends the speed signal and gas concentration signal of each measuring point to an external computer through the wireless transmission module. The power supply module is connected to the differential pressure sensor module, the gas concentration analysis module, the main controller module, and the wireless transmission module.

[0010] Furthermore, the jet assembly includes a jet cavity, m jet elements, and m jet outlet pipes. A negative pressure channel on the jet cavity is connected to the gas concentration test chamber in the measurement cavity, and the negative pressure channel is correspondingly located above the nozzle of the jet element. The jet outlet pipe is installed at the outlet of the nozzle. The jet elements are installed in the jet cavity, and the jet elements have multiple jet blowing ports along the circumference. The jet cavity has an air source hole that communicates with the jet blowing ports of each jet element for blowing compressed gas into the jet element.

[0011] Furthermore, the Pitot tube includes a base, a total pressure measuring tube, and a static pressure measuring tube. The total pressure measuring tube faces the airflow direction, and the static pressure measuring tube faces away from the airflow direction. The side of the base closest to the two measuring tubes is set as an arc surface, and the radius of the arc surface is consistent with the outer diameter of each outer tube. Each connector includes a side connection part and a middle connection part. The side connection part is a circular plate with the same outer diameter as the outer tube, and the middle connection part is installed in conjunction with the base of the Pitot tube.

[0012] Furthermore, a seal is provided between the base of the Pitot tube and the middle connection of the connector, a seal is provided between the side connection of the connector and the outer tube, and a seal is provided between the outer tube of the base section and the measuring cavity.

[0013] Furthermore, it also includes a backflush system, which includes backflush pipelines and a solenoid valve assembly. The measuring chamber has m sets of backflush pipelines, which are simultaneously connected to the compressed gas pipeline. The solenoid valve assembly includes m solenoid valves, each of which is connected between the compressed gas pipeline and each backflush pipeline. Each backflush pipeline is connected to the pressure transmission pipe and gas concentration transmission pipe of each measuring point. The solenoid valve assembly is signal-connected to the main controller module.

[0014] Furthermore, the negative pressure channel is equipped with stepped holes and a spring ball structure. When the backflush system is started, the pressure of the compressed gas forces the ball to move downward to block the negative pressure channel. Under normal test conditions, the spring ball is suspended in the negative pressure channel to allow airflow.

[0015] Furthermore, it also includes a compressed gas heating pipeline, the inlet of which is located on the measuring chamber, and a gas heating hole is provided in the measuring chamber. Each outer sleeve and each connector is provided with a gas heating circuit, and the outlet of the gas heating circuit is connected to the compressed gas pipeline in the measuring chamber. The compressed gas pipeline is used to introduce compressed gas into the backflush system and the jet assembly.

[0016] Furthermore, a heating rod is installed near the compression pipeline inside the measuring chamber to heat the compressed gas.

[0017] The method and system provided by this invention test the gas velocity and concentration fields on the flue gas cross-section using a gridded measurement point arrangement. Multiple measurement points can be tested simultaneously in real time. Compared with multi-point sampling and surveying, this method can more accurately reflect the current flue gas state within the pipe cross-section, and the collected data is more precise. This provides accurate data for subsequent data analysis, monitoring, and control, meeting the requirements for precise measurement of flue gas emissions. The entire system is linked by n probe testing devices, each with its own testing system. This results in a short data transmission path and fast response speed. Each probe testing device has its pressure transmission pipe and gas concentration transmission pipe installed inside an outer casing, allowing direct measurement of pressure and concentration. Differential signals and gas concentration signals are transmitted to each individual testing system, eliminating the need for extensive piping like traditional methods, thus saving costs and facilitating later maintenance. Each probe testing device can be assembled on-site, and the length of the probe assembly can be customized by selecting the number of extension sections based on the pipe size, with customizable lengths for easy transportation and greater flexibility than traditional fixed-length sampling pipe network layouts. The jet assembly, in conjunction with the measuring chamber structure, allows the sample gas from each measuring point to be directly introduced into the testing system for gas concentration testing. Heating pipes or heating rods are installed to heat the compressed gas entering the jet chamber, preventing blockage caused by water vapor condensation at the jet outlet. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system measurement point layout provided by the present invention; Figure 2 This is a three-dimensional structural diagram of the probe testing device provided by the present invention; Figure 3 This is a three-dimensional structural diagram of the probe testing device provided by the present invention with the housing in the open state. Figure 4 A schematic diagram of the measurement and control module provided by the present invention; Figure 5 Exploded view of the probe assembly provided by this invention; Figure 6 for Figure 5 Enlarged structural diagrams at points A, B, and C in the middle; Figure 7A schematic diagram of the three-dimensional structure of the Pitot tube provided by the present invention; Figure 8 A three-dimensional structural diagram of the base segment connector and the pitot tube in a specific embodiment of the present invention; Figure 9 A three-dimensional structural diagram of the first connector and the pitot tube in a specific embodiment of the present invention; Figure 10 A three-dimensional structural diagram of the second connector and the pitot tube in a specific embodiment of the present invention; Figure 11 A three-dimensional structural diagram of the measuring cavity assembly provided by the present invention; Figure 12 A three-dimensional structural diagram of the measuring cavity assembly provided by the present invention from another direction; Figure 13 This is a front view of the measurement cavity assembly provided by the present invention; Figure 14 Provided by the present invention Figure 13 Sectional view along axis AA; Figure 15 A three-dimensional structural diagram of the jetting component provided by the present invention; In the diagram: 1. Flue; 2. Probe testing device; 21. Probe assembly; 211. Pitot tube; 211-1. Pressure testing port; 211-2. Gas inlet; 211-3. Base; 211-4. Total pressure testing tube; 211-5. Static pressure testing tube; 212. Connector; 212a. Base section connector; 212b. First connector; 212c. Second connector; 213. Outer sleeve; 213a. Base section outer sleeve; 213b. First outer sleeve; 213c. Second outer sleeve; 214. Pressure transmission pipe; 214a. Base section pressure transmission pipe; 214b. First pressure transmission pipe; 214c. Second pressure transmission pipe; 215. Gas concentration transmission pipe; 215a. Base section gas concentration transmission pipe; 215b. First gas concentration transmission pipe; 215c. Second gas concentration transmission pipe; 216. Connecting flange; 22. Measuring chamber assembly; 221. Measuring chamber; 222. Jet assembly; 222-1. Jet chamber; 222-2. Jet component; 222-2a. Jet outlet; 222-2b. Nozzle; 222-3. Jet outlet pipe; 222-4. Negative pressure channel; 222-5. Spring ball structure; 223. Gas concentration sensor; 23. Insulation shell; 24. Measurement and control module; 25. Box body. Detailed Implementation

[0019] To more clearly illustrate the present invention, the invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] A gas velocity and concentration testing system for a pipeline cross-section includes n probe testing devices 2 symmetrically inserted into a flue 1, where n ≥ 4. Each probe testing device 2 has m measuring points evenly distributed along the depth direction of the pipeline cross-section, where m ≥ 2. The measuring points are arranged in a grid on the pipe measuring section; In this embodiment, a rectangular pipe is used, such as... Figure 1 As shown, n is 12, meaning that 6 probe testing devices 2 are symmetrically arranged on the upper and lower sides of the rectangular pipe. Each probe testing device 2 inserted into the flue has 3 measuring points evenly distributed along the depth direction of the pipe cross-section. The measuring points are arranged in a grid on the pipe cross-section.

[0021] like Figure 2 and Figure 3 As shown, the probe testing device 2 includes a probe assembly 21, a measuring cavity assembly 22, an insulation shell 23, a measurement and control module 24, and a housing 25. The probe assembly 21 is installed outside the housing 25 and connected to the measuring cavity assembly 22. The measuring cavity assembly 22 and the measurement and control module 24 are both located inside the housing 25, and the insulation shell 23 is installed outside the measuring cavity assembly 22. like Figure 5 and Figure 6 As shown, the probe assembly 21 includes a base section and m-1 extension sections. Both the base section and the extension sections include a Pitot tube 211, a connector 212, an outer tube 213, a pressure transmission tube 214, and a gas concentration transmission tube 215. The Pitot tube 211 is fixed between the two outer tubes 213 by the connector 212. The Pitot tube 211 is provided with two pressure measuring ports 211-1 and a gas inlet 211-2. The opening direction of the two pressure measuring ports 211-1 is arranged back and forth along the flue gas flow direction. The pressure transmission tube 214 and the gas concentration transmission tube 215 are both arranged inside the outer tube 213. like Figures 11 to 14 As shown, the measuring chamber assembly 22 includes a measuring chamber 221, a jet assembly 222, and a gas concentration sensor 223. The measuring chamber 221 has a pressure test chamber connected to the pressure transmission pipe 214 of each measuring point and a gas concentration test chamber connected to each gas concentration transmission pipe 215. The pressure difference of each measuring point is led to the measurement and control module 24 through the two pressure measuring ports 211-1 on the Pitot tube 211, the pressure transmission pipe 214, and the pressure test chamber in sequence. The gas at each measuring point is led to the measurement and control module 24 through the gas inlet 211-2 on the Pitot tube 211, the gas concentration transmission pipe 215, the gas concentration test chamber, and the gas concentration sensor 223 in sequence. The negative pressure channel 222-4 of the jet assembly 222 is connected to each gas concentration test chamber to form a negative pressure to introduce gas at each measuring point.

[0022] like Figures 5 to 10 As shown, in this embodiment, the probe assembly 21 includes a base section and two extension sections. The base section includes a Pitot tube 211, a base section connector 212a, a base section outer sleeve 213a, a connecting flange 216, a base section pressure transmission pipe 214a, and a base section gas concentration transmission pipe 215a. The first extension section includes a Pitot tube 211, a first connector 212b, a first outer sleeve 213b, a first pressure transmission pipe 214b, and a first gas concentration transmission pipe 215b. The second extension section includes a Pitot tube 211, a second connector 212c, a second outer sleeve 213c, a second pressure transmission pipe 214c, and a second gas concentration transmission pipe 215c. One end of the base section outer sleeve 213a is sealed and fixed to the outside of the housing 25 via a connecting flange 216. The other end of the base section outer sleeve 213a is sealed and connected to one end of the first outer sleeve 213b via a base section connector 212a. The other end of the first outer sleeve 213b and one end of the second outer sleeve 213c are sealed and connected via a first connector 212b. The second connector 212c is sealed and connected to the other end of the second outer sleeve 213c. Three Pitot tubes 211 are fixed to the base section connector 212a, the first connector 212b, and the second connector 212c, respectively. Six base section pressure transmission pipes 214a and three base section gas concentration transmission pipes 215a are evenly arranged inside the base section outer sleeve 213a. Four first pressure transmission pipes 214b and two first gas concentration transmission pipes 215b are evenly arranged inside the first outer sleeve 213b. Two second pressure transmission pipes 214c and one second gas concentration transmission pipe 215c are evenly arranged inside the second outer sleeve 213c. With the above structural arrangement, the pressure signal and gas concentration signal of each measuring point have their own independent transmission path, without interfering with or affecting each other. There is no need to set up separate solenoid valves for sequential on / off switching, which simplifies the control and improves the measurement accuracy and efficiency.

[0023] In this application, one flue section can be simultaneously subjected to... The system performs real-time online testing of gas concentration and velocity fields at multiple measuring points. The gridded layout of the measuring points allows for precise data acquisition. The entire system is interconnected via n probe testing devices 2, each with its own control module 24. This results in short data transmission paths and fast response times. Pressure transmission pipes 214 and gas concentration transmission pipes 215 are both housed within the outer casing 213, directly transmitting differential pressure and gas concentration signals to each control module 24. This eliminates the need for extensive piping, saving costs and facilitating future maintenance. Each probe testing device 2 can be assembled on-site, and the length of the probe assembly 21 can be adjusted according to... The number of extension sections is selected according to the pipeline size, and the length of the extension sections can also be customized, which facilitates transportation and is more flexible in terms of network layout than traditional fixed-length sampling pipes. The differential pressure signal and gas concentration signal of each measuring point can be transmitted to each measurement and control module 24 at the same time. The measurement and control module 24 performs gas concentration analysis and calculates the instantaneous gas velocity at each measuring point according to the differential pressure formula. It also sends the velocity field and concentration field data of each measuring point to an external computer at the same time. Compared with multi-point sampling and survey, it can truly reflect the flue gas state in the current pipeline section. The collected data is more accurate and can provide accurate data for subsequent data analysis, monitoring and control, thus meeting the requirements for accurate measurement of flue gas emissions.

[0024] Specifically, each connector 212 has several through holes, which are used to connect the pressure measuring port 211-1 on the Pitot tube 211 to the pressure transmission tube 214 and the gas inlet 211-2 to the gas concentration transmission tube 215, respectively.

[0025] As shown in the figure, in this embodiment, the base section connector 212a includes six sets of left-right interconnecting through holes A and three sets of L-shaped through holes B. The through holes A are used to connect the base section pressure transmission pipe 214a and the first pressure transmission pipe 214b, and the base section gas concentration transmission pipe 215a and the first gas concentration transmission pipe 215b, respectively. The through holes B are used to connect the remaining base section pressure transmission pipes 214a to the two pressure measuring ports 211-1, and the remaining base section gas concentration transmission pipes 215a to the gas inlet 211-2. Similarly, the first connector 212b includes three sets of left-right interconnecting through holes A and three sets of L-shaped through holes B. The first pressure transmission pipe 214b and the second pressure transmission pipe 214c, as well as the first gas concentration transmission pipe 215b and the second gas concentration transmission pipe 215c, are connected by through holes B and A, respectively. Through holes B are used to connect the remaining first pressure transmission pipes 214b with the two pressure measuring ports 211-1 and the remaining first gas concentration transmission pipes 215b with the gas inlet 211-2. The second connector 212c includes three sets of L-shaped through holes B, which are used to connect the second pressure transmission pipes 214c with the two pressure measuring ports 211-1 and the second gas concentration transmission pipes 215c with the gas inlet 211-2.

[0026] Specifically, such as Figure 4 As shown, the measurement and control module 24 includes a differential pressure sensor module, a gas concentration analysis module, a main controller module, a power supply module, and a wireless transmission module. The differential pressure at each measuring point is simultaneously transmitted to the differential pressure sensor module through the pressure measuring port 211-1 of each pitot tube 211. The gas concentration at each measuring point is simultaneously transmitted to the gas concentration analysis module through the gas inlet 211-2 on each pitot tube 211. The differential pressure sensor module and the gas concentration measurement sensor module are respectively connected to the main controller module. The main controller module sends the speed signal and gas concentration signal of each measuring point to an external computer through the wireless transmission module. The power supply module is connected to the differential pressure sensor module, the gas concentration measurement sensor module, the main controller module, and the wireless transmission module.

[0027] The wireless transmission module in this embodiment can also be replaced by a wired transmission mode.

[0028] like Figure 14 and Figure 15 As shown, the jet assembly 222 includes a jet cavity 222-1, m jet elements 222-2, and m jet outlet pipes 222-3. A negative pressure channel 222-4 is opened on the jet cavity 222-1 and communicates with the gas concentration test chamber in the measurement cavity. The negative pressure channel 222-4 is correspondingly arranged above the nozzle 222-2b of the jet element 222-2. The jet outlet pipe 222-3 is installed at the outlet of the nozzle 222-2b. The jet element 222-2 is installed in the jet cavity 222-1. The jet element 222-2 has multiple jet blowing ports 222-2a opened in the circumferential direction. The jet cavity 222-1 has an air source hole that communicates with the jet blowing ports 222-2a of each jet element 222-2 for blowing compressed gas into the jet element 222-2.

[0029] In this embodiment, the jet assembly 222 includes three jet elements 222-2 and three jet outlet pipes 222-3. The three negative pressure channels 222-4 opened in the jet cavity 222-1 correspond to the area above the nozzle 222-2b of each jet element 222-2. Compressed gas enters the jet blowing port 222-2a of each jet element 222-2 from the jet cavity 222-1 and is blown out from the nozzle 222-2b, forming a negative pressure area around the nozzle. Three gas concentration sensors 223 are installed in the measuring cavity 221. The gas sensing holes of the gas concentration sensors 223 are correspondingly set in the gas path connecting the gas concentration testing chamber and the negative pressure channel 222-4. Under the action of negative pressure, the gas at each measuring point enters the gas concentration sensor 223 for gas concentration measurement.

[0030] like Figures 7 to 10As shown, the Pitot tube 211 includes a base 211-3, a total pressure measuring tube 211-4, and a static pressure measuring tube 211-5. The total pressure measuring tube 211-4 faces the airflow direction, and the static pressure measuring tube 211-5 faces away from the airflow direction. The side of the base 211-3 closest to the two measuring tubes is set as an arc surface, and the radius of the arc surface is the same as the outer diameter of each outer tube 213. Each connector 212 includes a side connection part and a middle connection part. The side connection part is a circular plate with the same outer diameter as the outer tube 213. The middle connection part is installed in conjunction with the base 211-3 of the Pitot tube 211.

[0031] The above structural design allows the pitot tube 211 to form a cylinder with the same outer diameter as the outer sleeve 213 after being connected to the connector 212. The probe assembly 21 forms an integral long cylindrical rod structure, avoiding disturbances during flue gas flow and further improving measurement accuracy.

[0032] A seal is provided between the base 211-3 of the Pitot tube 211 and the middle connecting part of the connector 212, a seal is provided between the side connecting part of the connector 212 and the outer tube 213, and a seal is provided between the outer tube 213a of the base section and the measuring cavity 221.

[0033] Furthermore, the gas velocity and concentration testing system for the pipeline cross-section also includes a backflushing system. The backflushing system comprises backflushing pipelines and a solenoid valve assembly. The measuring chamber 221 has m sets of backflushing pipelines, all connected to the compressed gas pipeline. The solenoid valve assembly includes m solenoid valves, each connected between the compressed gas pipeline and each backflushing pipeline. Each backflushing pipeline is connected to the pressure transmission pipe 214 and gas concentration transmission pipe 215 of each measuring point. The solenoid valve assembly is signal-connected to the main controller module. The main controller module sequentially controls the opening and closing of each solenoid valve, causing the compressed gas to backflush the gas inlet and pressure port of each measuring point sequentially, preventing pipeline blockage.

[0034] Furthermore, such as Figure 14 As shown, a stepped hole is provided in the negative pressure channel 222-4, and a spring ball structure 222-5 is installed. When the backflush system is started, the pressure of the compressed gas forces the ball to move downward to block the negative pressure channel 222-4. Under normal test conditions, the spring ball is suspended in the negative pressure channel 222-4 to allow airflow. This mechanical structure prevents compressed gas from entering the jet assembly during backflush, eliminating the need for separate electronic control components to select the compressed gas path, making the structure simpler and more convenient.

[0035] The gas velocity and concentration testing system for pipeline cross-sections also includes a compressed gas heating pipeline. The inlet of the compressed gas heating pipeline is located on the measuring chamber 221, and a gas heating hole is opened inside the measuring chamber 221. Each outer sleeve 213 and each connector 212 is equipped with a gas heating circuit, and the outlet of the gas heating circuit is connected to the compressed gas pipeline inside the measuring chamber 221. Compressed gas enters through the inlet of the compressed gas heating pipeline, and sequentially passes through the gas heating hole and the gas heating circuit into the compressed gas pipeline.

[0036] Through the above path design, the high temperature inside the flue can be used to heat the compressed gas entering the system, avoiding condensation of the compressed gas in the backflushing system and jet assembly 222, which would affect the operation of the entire test system.

[0037] Alternatively, as another preferred option, a heating rod can be installed near the compression line inside the measuring chamber 221 to heat the compressed gas.

[0038] Those skilled in the art should understand that, in the description of this invention, the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the purpose of facilitating the description of this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0039] In this invention, unless otherwise explicitly specified and limited, for example, it can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements or an interaction between two elements. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this invention. For those skilled in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this invention. The scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A system for testing gas velocity and concentration in a pipeline cross-section, characterized in that, It includes n probe testing devices symmetrically inserted into the flue, n≥4, each probe testing device has m test points evenly distributed along the depth direction of the pipe section, m≥2, and the m×n test points are arranged in a grid on the pipe measurement section; The probe testing device includes a probe assembly, a measuring cavity assembly, an insulation shell, a measurement and control module, and a housing. The probe assembly is installed outside the housing and connected to the measuring cavity assembly. The measuring cavity assembly and the measurement and control module are both located inside the housing, and the insulation shell is installed outside the measuring cavity assembly. The probe assembly includes a base section and m-1 extension sections. Both the base section and the extension sections include a Pitot tube, a connector, an outer sleeve, a pressure transmission tube, and a gas concentration transmission tube. The Pitot tube is fixed between the two outer sleeves by the connector. The Pitot tube is provided with two pressure measuring ports and a gas inlet. The opening direction of the two pressure measuring ports is arranged back and forth along the flue gas flow direction. The pressure transmission tube and the gas concentration transmission tube are both installed inside the outer sleeve. The measurement chamber assembly includes a measurement chamber, a jet assembly, and a gas concentration sensor. The measurement chamber has a pressure test chamber connected to the pressure transmission pipes of each measurement point and a gas concentration test chamber connected to the gas concentration transmission pipes of each measurement point. The pressure difference of each measurement point is sequentially led to the measurement and control module through the two pressure test ports on the Pitot tube, the pressure transmission pipe, and the pressure test chamber. The gas at each measurement point is sequentially led to the measurement and control module through the gas inlet on the Pitot tube, the gas concentration transmission pipe, the gas concentration test chamber, and the gas concentration sensor. The negative pressure channel of the jet assembly is connected to each gas concentration test chamber to form a negative pressure to introduce gas at each measurement point.

2. The pipeline cross-section gas velocity and concentration testing system according to claim 1, characterized in that, Each connector has several through holes, which are used to connect the pressure measuring port on the pitot tube to the pressure transmission tube and the gas inlet to the gas concentration transmission tube, respectively.

3. The gas velocity and concentration testing system for pipeline cross-sections according to claim 2, characterized in that, The measurement and control module includes a differential pressure sensor module, a gas concentration analysis module, a main controller module, a power supply module, and a wireless transmission module. The differential pressure at each measuring point is simultaneously transmitted to the differential pressure sensor module through the pressure measuring port on each pitot tube, and the gas concentration at each measuring point is simultaneously transmitted to the gas concentration analysis module through the gas inlet on each pitot tube. The differential pressure sensor module and the gas concentration analysis module are respectively connected to the main controller module. The main controller module sends the velocity signal and gas concentration signal of each measuring point to an external computer through the wireless transmission module. The power supply module is connected to the differential pressure sensor module, the gas concentration analysis module, the main controller module, and the wireless transmission module.

4. The pipeline cross-section gas velocity and concentration testing system according to claim 3, characterized in that, The jet assembly includes a jet cavity, m jet elements, and m jet outlet pipes. A negative pressure channel on the jet cavity is connected to the gas concentration test chamber in the measurement cavity, and the negative pressure channel is correspondingly located above the nozzle of the jet element. The jet outlet pipe is installed at the outlet of the nozzle. The jet elements are installed in the jet cavity, and the jet elements have multiple jet blowing ports along the circumference. The jet cavity has an air source hole that is connected to the jet blowing ports of each jet element for blowing compressed gas into the jet element.

5. The pipeline cross-section gas velocity and concentration testing system according to claim 4, characterized in that, The Pitot tube includes a base, a total pressure measuring tube, and a static pressure measuring tube. The total pressure measuring tube faces the airflow direction, and the static pressure measuring tube faces away from the airflow direction. The side of the base closest to the two measuring tubes is set as an arc surface, and the radius of the arc surface is the same as the outer diameter of each outer tube. Each connector includes a side connection part and a middle connection part. The side connection part is a circular plate with the same outer diameter as the outer tube, and the middle connection part is installed in conjunction with the base of the Pitot tube.

6. The pipeline cross-section gas velocity and concentration testing system according to claim 5, characterized in that, A seal is provided between the base of the Pitot tube and the middle connection of the connector, a seal is provided between the side connection of the connector and the outer tube, and a seal is provided between the outer tube of the base section and the measuring cavity.

7. The pipeline cross-section gas velocity and concentration testing system according to any one of claims 3 to 6, characterized in that, It also includes a backflush system, which includes backflush pipelines and a solenoid valve assembly. The measuring chamber has m sets of backflush pipelines, which are simultaneously connected to the compressed gas pipeline. The solenoid valve assembly includes m solenoid valves, each of which is connected between the compressed gas pipeline and each backflush pipeline. Each backflush pipeline is connected to the pressure transmission pipe and gas concentration transmission pipe of each measuring point. The solenoid valve assembly is connected to the main controller module.

8. The pipeline cross-section gas velocity and concentration testing system according to claim 7, characterized in that, The negative pressure channel is equipped with stepped holes and a spring ball structure. When the backflush system is started, the pressure of the compressed gas forces the ball to move downward to block the negative pressure channel. Under normal test conditions, the spring ball is suspended in the negative pressure channel to allow airflow.

9. The pipeline cross-section gas velocity and concentration testing system according to claim 8, characterized in that, It also includes a compressed gas heating pipeline, the inlet of which is located on the measuring chamber, and a gas heating hole is provided in the measuring chamber. Each outer sleeve and each connector is provided with a gas heating circuit, and the outlet of the gas heating circuit is connected to the compressed gas pipeline in the measuring chamber. The compressed gas pipeline is used to introduce compressed gas into the backflush system and the jet assembly.

10. The pipeline cross-section gas velocity and concentration testing system according to claim 8, characterized in that, A heating rod is installed near the compression pipeline inside the measuring chamber to heat the compressed gas.

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