Filtering performance detection device for two-stage filtering system

Abstract

The invention discloses a filtering performance detection device for a two-stage filtering system, and belongs to the technical field of building filtering and ventilation. Comprising an air generation and pretreatment device, an aerosol generation device, an aerosol treatment device, an experiment pipeline, an airflow adjusting device, a measurement and control system and a tail gas treatment device. A positive pressure environment required by the test is provided through the air compressor; dry and clean air flow is obtained after pretreatment through a pre-filtering device; real-time changes of air flow in the experiment and upstream and downstream pressure difference of the filter material in the testing process are tested; monitoring the particle size distribution change of upstream and downstream aerosols of the filter material in the testing process; all data parameters such as air inlet flow, branch flow, tail gas flow, air inlet pressure, air outlet pressure and differential pressure of the device are displayed and recorded, and real-time and historical curves are generated. According to the invention, a certain basis is provided for prolonging the service life and improving the dust holding capacity of the multistage filter of the building ventilation system, and a reference is provided for design and combination of the multistage filter under other application backgrounds such as clean rooms and laboratories.

Description

Technical Field

[0001] The present invention belongs to the technical field of building filtration ventilation, and particularly relates to a detection device for the filtration performance of a two-stage filtration system. Background Art

[0002] Particulates, as the main pollutants in the air, their impact on human health and the air environment has been proven in many fields. The indoor air environment of buildings is one of the most important conditions for people's work and life. Ventilation and air change, that is, the use of air filters, can effectively reduce the indoor particulate concentration and improve the indoor air quality. As the use time prolongs, the pressure drop of the air filter often gradually increases with the increase of the particle deposition amount, so it needs to be replaced regularly. Replacing the air filter involves material costs, labor costs, downtime costs, etc. Based on this, before large particles reach the high-efficiency filter material, they are first captured by pre-filter materials and coarse filter materials with low pressure drop, which can increase the dust holding capacity of the high-efficiency filter, reduce the pressure drop of the high-efficiency filter, and extend the service life of the high-efficiency filter. In high-cleanliness and high-safety purification systems, filters are often used in series, that is, multi-stage filtration is adopted to achieve the desired effect.

[0003] Although filtration systems with different grades of filter materials are widely used, there is a lack of relevant academic research on the influencing factors of filtration performance such as the resistance curve, efficiency, dust holding capacity, and service life during the filtration process of multi-stage filtration systems, the matching of multi-stage filtration materials, and their mutual influence. On the one hand, the existing detection devices for the filtration performance of laboratory two-stage filtration systems use pleated filter materials or small filters for experimental research, facing challenges such as the long time required in the preliminary preparation stage and the later experimental research stage, the complex and cumbersome installation process, and the inconvenience of filter material replacement. On the other hand, experimental research is carried out using test benches with small effective filtration areas of filter materials and manual clamping. Due to the small filtration area, problems such as low accuracy and decreased experimental stability occur when the dust holding capacity is low; in addition, most can only carry out filter material experiments, and there is a large error between the test results and the actual applied air filters, and the applicability of experimental data is poor; in addition, the existing experimental fixtures and system controls are mostly manual controls, with problems such as low integration, insufficient intelligence, complex operation, and backward clamping systems. In summary, the existing experimental research technologies cannot efficiently, stably, and reliably complete the research test on the filtration performance of two-stage filtration systems. Summary of the Invention

[0004] 1. Technical Problems to be Solved

[0005] In view of one or more of the problems or improvement requirements existing in the prior art, the present invention provides a device for detecting the filtration performance of a two-stage filtration system, including an air generation and pretreatment device, an aerosol generation device, an aerosol treatment device, an experimental pipeline, an air flow regulation device, a measurement and control system, and a tail gas treatment device, so as to meet the specific requirements of experimental research.

[0006] The object of the present invention is to propose a device for detecting the filtration performance of a two-stage filtration system. On the one hand, the device can be compatible with the experimental research of both filter media and small filters. On the other hand, it solves the problems of small effective filtration area, large error, and high limitations of test conditions in the existing two-stage test system. Its significance is not only to evaluate the filtration performance of the two-stage filtration system, but also to provide guidance for practical applications through performance testing and optimization results.

[0007] 2. Technical Solution

[0008] To solve the above problems, the present invention adopts the following technical solutions.

[0009] The present invention provides Figure 2 A device for detecting the filtration performance of a two-stage filtration system as shown, mainly including an air generation and pretreatment device, an aerosol generation device, an aerosol treatment device, an experimental pipeline, an air flow regulation device, a measurement and control system, a tail gas treatment device, etc. In the whole system, a positive pressure environment required for the test is provided by an air compressor; the dry and clean air flow after pretreatment by a pre-filter device is divided into a generation air flow and a dilution air flow. A small part of the generation air flow first enters the aerosol generation device to transport the generated aerosol particles to the aerosol drying tube. After drying, the aerosol is treated by an electrostatic neutralizer to reach the Boltzmann charge balance and then transported to the pipeline air inlet; the experimental pipeline is divided into a mixing pipeline and a test pipeline. Most of the dilution air flow enters the mixing pipeline through the front-end air inlet of the device and is mixed with the generation air flow to form a stable and uniform air flow; the test pipeline is located at the rear end of the mixing pipeline. Multiple sampling ports are arranged upstream and downstream of the pre-filter and main filter clamps and can realize the real-time switching function. The sampling ports are connected to a particle size spectrometer or a dust concentration meter to monitor the generation conditions in real time; the measurement and control system includes a detection device and an operation console. The operation console is divided into two parts: control and recording. The control system is connected to the test pipeline and can regulate the intake air flow and pressure in real time, as well as lift and lower the clamp to replace the test filter media. In addition, according to the test requirements, the intake air flow and the lifting and lowering of the clamp can be automatically controlled according to the set time for output and lifting; the operation console can also display and record all data parameters such as the intake air flow, branch air flow, tail gas flow, intake pressure, outlet pressure, differential pressure, etc. of the device and generate real-time and historical curves; in addition, the device also has a pressure alarm device. When the system pressure drop reaches a certain set value, it will give an alarm reminder, and at this time, the operator should promptly proceed with the next test.

[0010] The overall structure of the device is evenly and compactly arranged, with good overall sealing, feasibility, and stability. It is characterized in that the effective area of the filter paper test and the face velocity comply with the standards of 100 cm² and 5.33 cm / s in GB / T 13554-2020 "High-Efficiency Air Filters". The aerosol generation concentration complies with the standards of 15 mg / m³ - 20 mg / m³ in GB / T 13554-2020 "High-Efficiency Air Filters". The inlet air volume can be adjusted from 0 to 150 L / min, the branch flow rate can be adjusted from 0 to 150 L / min, and the tail-end flow rate can be adjusted from 0 to 50 L / min. The differential pressure gauge can achieve real-time monitoring from 0 to 2000 Pa. The special design of the limit rod supports the replacement of only the first-stage pre-filter media, and the support net design ensures the integrity and stability of the filter media under large flow test conditions. The filter media clamp can automatically control the lifting according to the settings, and an alarm will be given when the system pressure drop reaches a certain set value.

[0011] The compressed air generated by the air compressor enters the generating pipeline for generating the aerosol used in the test after pretreatment. After being mixed with clean air, it passes through components such as the first-stage test filter media or filter, the second-stage test filter media or filter, and the tail-end HEPA filter in the test pipeline, and then the pollution-free clean air is discharged into the atmosphere through the exhaust pipe. The air pretreatment device realizes functions such as storage, pressure stabilization, dehumidification, and purification of compressed air through the coordinated action of components such as the gas storage tank, pressure stabilizing valve, silica gel drying tube, and air filter triple unit. The gas storage tank is installed downstream of the air compressor. The gas storage tank is used to store the compressed air generated by the air compressor, and its buffering effect can reduce the frequent start and stop of the air compressor and eliminate the pulsation of the air flow in the pipeline. The outlet of the gas storage tank is connected to a pressure stabilizing valve. The pressure stabilizing valve not only ensures the stability and reliability of the pressure in this system but also meets the working requirements of different components by distributing different pressures. On the one hand, by adjusting the pressure stabilizing valve, a stable input pressure can be provided for the flow meter to ensure the accuracy and reliability of flow measurement and control; on the other hand, the cylinder drive system of this device requires a relatively large pressure to ensure its normal and efficient operation. The silica gel drying tube and the air filter triple unit are installed downstream of the pressure stabilizing valve to dry, filter, and purify the air. The silica gel drying tube removes the moisture in the compressed air through the adsorption of silica gel desiccant, and the air filter triple unit is used to remove fine particles and other impurities in the dried compressed air, and can effectively filter out particles with a diameter greater than 0.01 micrometers to ensure that the air quality reaches a high standard of purity.

[0012] The aerosol generation and treatment device consists of an aerosol generator, an aerosol drying tube, and an electrostatic neutralizer assembly. The aerosol generator is used to precisely control and generate aerosols with a constant particle size and concentration. Due to the portable, compact, and high-intensity design of the Collison spray aerosol generator, a polydisperse aerosol required for experimental detection can be extremely continuously and stably generated by atomizing the solution. The middle layer of the aerosol drying tube is a stainless steel wire mesh. When the aerosol passes through the diffusion drying tube, adsorbents such as molecular sieves in the outer layer can adsorb and remove the moisture in the aerosol, thereby forming a dry aerosol. This electrostatic neutralizer replaces the traditional radioactive source aerosol neutralizer. Its principle is based on corona discharge and does not generate X-rays, α-rays, β-rays, and γ-rays. It uses positive and negative ions generated by two independent ionization electrodes to adjust the charge distribution on the experimental aerosol particles, making the experimental aerosol in a Boltzmann equilibrium state.

[0013] The experimental pipeline includes a transverse aerosol mixing section, a longitudinal test filter medium or filter installation section, and a branch drainage section. The aerosol from the generation pipeline and the dilution air flow from the air inlet first pass through the mixing section, where the aerosol and the dilution air flow are fully mixed. To be compatible with small filter experiments, the fixture for the test filter medium is designed as a square and is connected to the test filter medium installation section through a stainless steel pipeline to facilitate the quick disassembly and assembly of the filter. To facilitate the study of the influence of replacing the first-stage pre-filter medium and the number of replacements on the second-stage main filter medium, a special limit rod design is added to the test pipeline. By controlling the installation and disassembly of the limit rod, only the first-stage pre-filter medium can be replaced, avoiding errors caused to the second-stage main filter medium due to the opening and closing of the fixture. In addition, the support mesh design on the fixture ensures the integrity and stability of the filter medium under large flow rate test conditions. The branch drainage section is designed to ensure stable air flow. By leading out a Y-shaped symmetric port from the test filter medium installation section, the flow rates of the branch and the tail end can be regulated. The tail gas treatment device is installed at the end of all air flows, including the end of the branch drainage pipe and the tail end exhaust pipe. The installed tail gas treatment device is a protective HEPA filter to prevent the test aerosol from entering the atmosphere and polluting the environment.

[0014] The air flow regulating device consists of air volume measuring instruments, which are respectively installed at the air inlet of the pipeline, the air outlet of the branch, and the air outlet of the tail end to monitor and control the real-time change of the air flow rate during the test process, and feedback the monitored data to the operation console for real-time regulation;

[0015] The detection device and the operation console form a measurement and control system. The detection device mainly consists of a differential pressure measuring instrument and a particle size spectrometer. The operation console realizes the control and recording of monitoring data. The air volume measuring instrument is respectively installed at the air inlet of the pipeline, the air outlet of the branch, and the air outlet of the tail end to monitor and control the real-time change of the air flow rate during the test process. The differential pressure measuring instrument is located at both the upstream and downstream ends of the first-stage test filter material and the second-stage test filter material to monitor the real-time change of the differential pressure across the filter material during the test process. The aerosol detection port is located at the upstream and downstream of the first-stage test filter material and the second-stage test filter material. The four-way valve connected to the rear end can realize the real-time switching of the detection port. The particle size spectrometer is installed at the rear end of the four-way valve to monitor the change of the particle size distribution of the aerosol across the filter material during the test process. Finally, the air volume measuring instrument and the differential pressure measuring instrument will feedback the monitoring data to the operation console for real-time regulation. In addition, when the system resistance monitored by the operation console reaches the set value, the alarm function will be activated to remind the experimenter to perform the next experimental operation in time.

[0016] 3. Beneficial effects

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] 1. For the filter performance detection device fixtures of filter materials and small filters, most are single-stage systems, and very few two-stage systems have problems such as small effective filtration area, large test error, and limited test conditions, making it difficult to meet the growing demand for precise testing. Especially when conducting the dust-holding experiment, small-area fixtures often lead to significant errors and are difficult to simultaneously accommodate the testing of filter materials and filters. The device designed in the present invention innovatively designs a fixture that meets the 100 cm2 test standard, which not only significantly improves the effective area of the test, reduces the error, but also realizes the full compatibility of filter materials and small filters, providing strong support for diverse experimental needs.

[0019] 2. The device designed in the present invention is equipped with a real-time switching aerosol detection port, allowing seamless monitoring of the upstream and downstream conditions of the first-stage and second-stage test filter materials during the test process, providing real-time data support for the precise analysis of filtration performance.

[0020] 3. The device designed in the present invention uses the design of a limit rod and a support net: The unique limit rod design improves the convenience of only replacing the first-stage pre-filter filter material during the experiment, effectively avoiding potential errors caused by the opening and closing of the fixture to the second-stage main filter filter material, and ensuring the accuracy of the test results. At the same time, the support net design under large-flow test conditions further ensures the integrity and stability of the filter material.

[0021] 4. The device designed by the present invention integrates a measurement and control system with a high level of automation. Through the real-time feedback of flow rate, pressure drop data, and the regulation of the fixture lifting, precise control of the test process is achieved. When the system resistance reaches the preset threshold, the alarm function is automatically triggered to timely remind the experimenter to take corresponding measures, ensuring the safe and efficient progress of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered as a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0023] Figure 1 is the structural layout diagram of the experimental device of the present invention;

[0024] Figure 2 is the three-dimensional schematic diagram of the main structure of the present invention;

[0025] Figure 3 is the side schematic diagram of the present invention;

[0026] Figure 4 is the schematic diagram of the test pipeline of the present invention;

[0027] In the figure: 1. Air compressor, 2. Gas storage tank, 3. Silica gel drying tube, 4. Filter triple unit, 5. Mass flow controller, 6. Display instrument, 7. Aerosol generating device, 8. Aerosol diffusion drying tube, 9. Electrostatic neutralizer, 10. Mixing pipeline, 11. Slide rail, 12. First-stage fixture, 13. Differential pressure measuring instrument, 14. Second-stage fixture, 15. Driving device, 16. Y-shaped branch drainage tube, 17. Tail-end exhaust pipe, 18. Two-way ball valve, 19. HEPA filter, 20. Mass flow meter, 21. Operation console, 22. Four-way ball valve, 23. Particle size spectrometer, 24. Computer, 25. First pipeline, 26. Aerosol detection port, 27. First-stage test filter material or filter, 28. Second pipeline, 29. Limit rod, 30. Second-stage test filter material or filter, 31. Third pipeline, 32. Support frame, 33. Instrument panel, 34. Pulley, 35. Dilution flow inlet, 36. Generation flow inlet, 37. Support mesh DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] The multi-stage filter can improve the dust-holding capacity of the entire filtration system, extend the service life of the high-efficiency filter, and reduce the energy consumption and operating costs of the filtration system. However, the protection effect and degree of the pre-filter on the main filter depend on the type, concentration, and particle size distribution of particles in the specific environment on the one hand, and on the matching method between the pre-filter and the main filter of different filtration grades on the other hand. By building a detection device for the filtration performance of a two-stage filtration system, this invention conducts research on the influencing factors of the filtration performance of the two-stage filtration system, the matching of the two-stage filter materials, and their mutual influence. It can not only provide a certain basis for improving the service life and dust-holding capacity of the multi-stage filter in the building ventilation system, but also provide a reference for the design and combination of multi-stage filters in other application backgrounds such as clean rooms and laboratories.

[0030] Example 1:

[0031] As Figure 1 shown, this invention provides a detection device for the filtration performance of a two-stage filtration system, which mainly consists of an air generation and pretreatment device, an aerosol generation device, an aerosol treatment device, an experimental pipeline, an air flow regulation device, a measurement and control system, a tail gas treatment device, etc. The entire device frame and panel are processed and assembled with stainless steel, and the pipeline joints are connected by welding to ensure the overall airtight performance.

[0032] The air generation and pretreatment device includes an air compressor 1, a gas storage tank 2, a silica gel drying tube 3, and a filter triple unit 4. The function of the air compressor 1 is to provide a stable high-pressure air source and transport compressed air to the entire system. The gas storage tank 2 at the rear is used to balance the air pressure fluctuation, stabilize the air flow output, and preliminarily purify the gas. The silica gel drying tube 3 plays a role in deep dehumidification and drying the compressed air. The filter triple unit 4 can effectively remove aerosols, dust, particulate matter, etc. with a particle size above 0.01um through multi-stage filtration, ensuring the purity and pressure stability of the output gas. The four work together to provide dry, clean, and appropriately pressurized compressed air required for the experiment.

[0033] The aerosol generation device 7 is used to generate the aerosol for testing. It can be an aerosol generation device for generating coarse particles such as A2 ash and A1 ash, or an aerosol generation device for generating fine particles such as Nacl, Kcl, DOP, and DEHS. The mass flow controller 5 at the front end can achieve precise control of the generation flow rate. Through the display instrument 6, the generated air flow rate can be observed and adjusted in real time. Under the action of the turbulence and shear force generated by the high-speed air flow, the particles are dispersed, refined, and evenly diffused with the air flow to form an aerosol with the required concentration for testing.

[0034] The aerosol treatment device includes an aerosol diffusion drying tube 8 and an electrostatic neutralizer 9. The aerosol diffusion drying tube 8 is connected to the rear end of the air outlet of the aerosol generating device 7. Through a special structural design, when the humid aerosol flows through the drying tube, the moisture in it is adsorbed by the desiccant in a diffused form. During this process, the aerosol particles do not come into direct contact with the desiccant, thus avoiding the loss of aerosol particles. The dried aerosol then enters the air inlet of the electrostatic neutralizer 9. This electrostatic neutralizer replaces the traditional radioactive source aerosol neutralizer. Instead of using radioactive sources Po-210 or Kr-85 to ionize the surrounding gas, it generates positive and negative ions based on corona discharge, adjusts the charge distribution of the experimental aerosol, achieves Boltzmann equilibrium, and simulates the natural charged state of particulate matter in the atmosphere.

[0035] The air flow generated by the air compressor 1 is mainly divided into two parts: the generation flow and the dilution flow, both of which are precisely regulated by the mass flow controller 5. As Figure 4 shown, the dry and clean compressed air enters the mixing pipe 10 from the dilution flow air inlet 35, and a certain flow rate of aerosol enters the mixing pipe 10 from the generation flow air inlet 36. The two together pass through the mixing pipe 10 and then enter the first pipe 25, where the aerosol and air are fully mixed.

[0036] As Figure 2 shown, the uniformly mixed aerosol passes through the first-stage clamp 12 and the second-stage clamp 14 in sequence and is respectively loaded on the first-stage test filter medium or filter 27 and the second-stage test filter medium or filter 30. The purpose of designing the test filter medium clamp as a square is to be compatible with small filter experiments and is connected to the test filter medium installation section through the slide rail 11 to facilitate the quick disassembly and assembly of the filter medium or filter. Under the large-flow test conditions, the special support mesh 37 design at the clamp can ensure the integrity of the filter medium and the stability of the test. The limit rod 29 is connected to the side of the second pipe 28 by threads. If the experimenter needs the first-stage clamp 12 and the second-stage clamp 14 to open and close simultaneously, the limit rod 29 is screwed onto the side of the pipe. When the clamp is controlled to open, under the support of the support frame 32, the second-stage clamp 14 will be in an open state; if the experimenter only replaces the first-stage test filter medium or filter 27, the limit rod 29 is disassembled. When the clamp is controlled to open, the second-stage clamp 14 will be in a closed state due to gravity, which can avoid the error caused by the opening and closing of the clamp to the second-stage test filter medium or filter 30.

[0037] As Figure 3As shown, the air flow regulating device is respectively connected to the sides of the second pipe 28 and the third pipe 31 through pipes. Tail gas treatment devices are installed at the ends of the discharged air flows. Specifically, a HEPA filter 19 is installed to filter out impurities and prevent the test aerosol from polluting the atmosphere. The function of the Y-shaped branch drain pipe 16 is to regulate the flow velocity of the test surfaces of the two-stage materials. To ensure the stability of the air flow, a Y-shaped symmetric drain pipe is led out from the side of the second pipe 28 and cooperates with the mass flow meter 20 at the rear end to achieve the purpose of adjustable branch flow. The HEPA filter 19 is installed in front of the mass flow meter 20 to protect the flow meter and the tail gas for clean treatment. The tail end exhaust pipe 17 works in coordination with the Y-shaped branch drain pipe 16 to regulate and monitor the air flow in the branch and at the tail end. A two-way ball valve 18 is added between the pipeline and the mass flow meter 20. Combined with the branch needle valve and the tail gas needle valve, precise regulation of the intake air flow is achieved to ensure the stable and efficient operation of the system. The driving device 15 is installed at the end of the tail end exhaust pipe 17. The second pipe 28 and the third pipe 31 are installed on the slide rail 11. The coordinated action of the driving device 15 and the slide rail 11 realizes the precise lifting control of the closing state of the device fixture.

[0038] The measurement and control system of the entire device consists of a detection device and an operation console 21. The detection device includes a differential pressure gauge 13 and a particle size spectrometer 23. The differential pressure gauge 13 is respectively installed at the upstream and downstream ends of the first-stage test filter material or filter 27 and the second-stage test filter material or filter 30 to monitor the real-time change of the differential pressure between the upstream and downstream of the filter material or filter during the test process. The aerosol detection ports 26 are respectively located downstream of the first pipe 25, upstream and downstream of the second pipe 28, and upstream of the third pipe 31. A four-way valve 22 is installed at the rear end of the particle size spectrometer 23. The four-way valve is used to switch the aerosol detection ports in real time during the test process. The particle size spectrometer 23 connected at the rear end is used to monitor the change of the particle size distribution of the aerosol between the upstream and downstream of the first-stage test filter material or filter 27 and the second-stage test filter material or filter 30 during the test process. The computer 24 is used to export the original data of the particle size distribution and further data processing.

[0039] Finally, the mass flow controller 5, the differential pressure gauge 15, and the mass flow meter 20 will feedback the monitored data to the operation console 21 for real-time regulation. The operation console 21 generally includes a display screen, a PLC, etc., and is used to control the corresponding components in this device. It can control the size of the air flow, pressure, and the closing of the fixture, etc. The operation console 21 can also display and record all data parameters such as the intake air flow, branch flow, tail gas flow, intake pressure, outlet pressure, differential pressure, etc. of this device and generate real-time and historical curves. In addition, when the system resistance reaches the preset threshold, the alarm function is automatically triggered to timely remind the experimenter to replace the filter material or filter or stop the experiment to ensure the safety and efficiency of the experiment. The pressure data, air flow data, and differential pressure data of this device are all displayed in real time on the instrument panel 33. The pulley 34 at the bottom of this device is designed to move at any time during use to flexibly adjust the position.

[0040] Example 2:

[0041] As Figure 1 shown, the present invention can play the role of testing the filtration efficiency and filtration resistance of the test filter media by replacing the detection device at the rear end. Standard test particles are added to the aerosol generating device 7, and the air flow rate and aerosol concentration are controlled to reach the required values according to the test conditions. After the generated aerosol is fully mixed with the dilution flow rate in the mixing pipe 10, it is loaded onto the test filter media. A laser particle counter or a turbidimeter is connected to the rear end of the aerosol detection port 26 to measure the particulate matter number concentration or mass concentration in the air downstream and upstream of the first-stage and second-stage test filter media. Then, according to the filtration efficiency calculation formula (1 - number of downstream particles / number of upstream particles) × 100%, the filtration efficiency is calculated and the average value is taken. The value of the differential pressure measuring instrument 13 during the test process is the filtration resistance of the test filter media.

[0042] Example 3:

[0043] As Figure 1 shown, the present invention can also be used to test the dust-holding performance of air filtration materials. First, the aerosol particle size distribution is measured by the aerosol particle size spectrometer 23. After the particle size distribution is adjusted to meet the dust-holding test standard, a stable-concentration aerosol is generated and the initial mass of the filter media or filter is weighed. A dust-holding experiment is carried out on the test filter media or filter. After the flow rate is stable, the initial resistance value of the filter media or filter is read, and the dust-holding termination resistance is input on the operation console 21. The differential pressure measuring instrument 13 records the resistance change of the filter media or filter in real time during this process. At equal time intervals during the dust-holding process, the resistance of the test filter media or filter and the test aerosol concentration are observed and recorded. When the operation console 21 activates the differential pressure alarm function, that is, the final resistance of the filter media or filter is reached, the aerosol generating device 7 in this device is turned off to terminate the dust-holding experiment. The fixture is opened and the final mass of the filter media or filter is weighed and recorded. After the data of the operation console 21 is exported and processed, the dust-holding capacity-resistance curve of the filter media or filter can be obtained.

[0044] This example aims to illustrate the necessity for the improvement of this method. However, the implementation mode of the present invention is not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A device for detecting the filtering performance of a two-stage filtering system, characterized in that It includes an air generation and pretreatment device, an aerosol generation device, an aerosol treatment device, an air flow regulation device, an experimental pipeline, a measurement and control system, and an exhaust gas treatment device; The air generation and pretreatment device includes an air compressor, a gas storage tank, a silica gel drying tube, and a filter triple unit. The air compressor is used to provide a stable high-pressure air source and deliver compressed air to the entire system; the gas storage tank located downstream of the air compressor is used to balance air pressure fluctuations, stabilize air flow output, and preliminarily purify the gas; the silica gel drying tube is used for deep dehumidification to dry the compressed air; the filter triple unit ensures the purity and pressure stability of the output gas through multi-stage filtration; The aerosol generation device is used to generate the aerosol for testing. The mass flow controller at the front end is used for precise control of the generation flow rate, and the air flow rate generated can be observed and regulated in real time through a display instrument; The aerosol treatment device includes an aerosol diffusion drying tube and an electrostatic neutralizer; the aerosol diffusion drying tube is connected to the rear end of the air outlet of the aerosol generation device and is used to adsorb the moisture in the humid aerosol in the form of diffusion by the desiccant when the aerosol flows through the drying tube; the dried aerosol enters the air inlet of the electrostatic neutralizer to adjust the charge distribution of the experimental aerosol; The air flow regulation device consists of air volume measuring instruments, and the air volume measuring instruments are respectively installed at the air inlet of the pipeline, the air outlet of the branch, and the air outlet of the tail end to monitor and control the real-time change of the air flow rate during the test process, and feedback the monitoring data to the operation console for real-time regulation; The experimental pipeline is divided into a mixing pipeline and a test pipeline. The test pipeline is located at the rear end of the mixing pipeline. Multiple sampling ports are arranged upstream and downstream of the pre-filter and main filter fixtures and a real-time switching function is realized. The sampling ports are connected to a particle size spectrometer or a dust concentration meter for real-time monitoring of the generation conditions; the experimental pipeline includes a horizontal aerosol mixing section, a longitudinal section for installing the test filter material or filter, and a branch drainage section; a limiting rod is added to the experimental pipeline, and a support mesh is designed on the fixture; The measurement and control system consists of a detection device and an operation console. The detection device includes a differential pressure measuring instrument and a particle size spectrometer. The operation console realizes the control and recording of the monitoring data; the differential pressure measuring instrument is located at both ends of the upstream and downstream of the first-stage test filter material and the second-stage test filter material to monitor the real-time change of the differential pressure between the upstream and downstream of the filter material during the test process; the aerosol detection ports are located at the upstream and downstream of the first-stage test filter material and the second-stage test filter material, and the four-way valve connected to the rear end realizes the real-time switching of the detection ports. The particle size spectrometer is installed at the rear end of the four-way valve and is used to monitor the change of the particle size distribution of the aerosol between the upstream and downstream of the filter material during the test process; the differential pressure measuring instrument is used to feedback the monitoring data to the operation console for real-time regulation; The exhaust gas treatment device is installed at the end of all air flows, including the end of the branch drainage pipe and the tail end exhaust pipe. The exhaust gas treatment device is a protective HEPA filter to prevent the test aerosol from entering the atmosphere and polluting the environment.

2. The filtering performance detection device of a two-stage filtering system according to claim 1, characterized in that, The aerosol generation device is used to generate coarse particle aerosols of A2 ash and A1 ash, or fine particle aerosols of Nacl, Kcl, DOP, and DEHS.

3. The filtering performance detection device of a two-stage filtering system according to claim 1, characterized in that, The measurement and control system is divided into two parts: control and recording. The control part is connected to the test pipeline to regulate the intake air flow and pressure in real time, and to lift and lower the fixture for replacing the test filter media. It automatically controls the output and lifting of the intake air flow and the fixture according to the set time in accordance with the test requirements. The recording part can record the data parameters of the intake air flow, branch flow, exhaust gas flow, intake air pressure, outlet air pressure, and differential pressure of the device and generate real-time and historical curves.

4. A device for detecting the filtration performance of a two-stage filtration system according to claim 1, characterized in that, The air filter triple unit can effectively filter out particles with a diameter greater than 0.01 microns to ensure that the air quality reaches a high standard of purity.

5. The filtering performance detection device of a two-stage filtering system according to claim 1, characterized in that, The outlet of the gas storage tank is connected to a pressure stabilizing valve to ensure the stability and reliability of the pressure.

6. The filtering performance detection device of a two-stage filtering system according to claim 1, characterized in that, When the system resistance monitored by the operation console reaches the set value, the alarm function will be activated to remind to perform the next experimental operation in a timely manner.

7. A filtering performance detection device for a two-stage filtering system according to claim 1, characterized in that, The air intake volume of the device can be regulated from 0 to 150 L / min, the branch flow can be regulated from 0 to 150 L / min, the tail-end flow can be regulated from 0 to 50 L / min, and the differential pressure gauge can achieve real-time monitoring from 0 to 2000 Pa.

8. A device for detecting the filtering performance of a two-stage filtering system according to claim 1, characterized in that, The fixture for the test filter media can be automatically controlled to lift and lower according to the setting, and an alarm will be given after the system pressure drop reaches a certain set value.

9. A device for detecting the filtering performance of a two-stage filtering system according to claim 8, characterized in that, The fixture for the test filter media is designed to be square and is connected to the installation section of the test filter media through a stainless steel pipe to facilitate the quick disassembly and assembly of the filter.

10. The filtering performance detection device of a two-stage filtering system according to claim 1, characterized in that, In order to ensure the stability of the air flow in the branch drainage section, a Y-shaped symmetric port is led out from the installation section of the test filter media to enable the regulation of the branch and tail-end flows.

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