Aerosol Dilution Method Calibration Device and Calibration Method for Mask Particle Filtration Efficiency

Abstract

The present invention discloses an aerosol dilution method calibration device and a calibration method for the particulate matter filtration efficiency of a mask. The calibration device includes an upstream pressure sampler, a flow-limiting capillary, a filter, a shunt, a downstream pressure sampler, a digital differential pressure gauge, an upstream pressure sampling port, a downstream pressure sampling port, an air outlet, an inner ring air inlet, a shunt pressure sampling port, and a resistance regulator. By using the present invention, the disassembly and reconnection of the tester pipeline during the calibration process can be avoided, and the interference of the standard device introduced to the working conditions of the tester is minimized; during the calibration process, only the number of capillaries participating in flow limitation needs to be changed for calibration, and the digital differential pressure gauge is used to record the upstream and downstream pressure differences, thus greatly simplifying the calibration process and saving calibration time; the calibration device does not involve high-value standard devices and equipment, greatly saving the calibration cost; the traceability chain of the filtration efficiency calibration process is clear, avoiding the introduction of more factors participating in uncertainty evaluation.

Description

Technical Field

[0001] The present invention relates to the technical field of mask detection, and particularly relates to an aerosol dilution method calibration device and calibration method for the particulate matter filtration efficiency of masks. Background Art

[0002] At present, the particulate matter filtration efficiency of masks is measured by simultaneously sampling and measuring the aerosol before and after passing through the mask by the upstream and downstream aerosol photometers of the tester. The result is calculated after background subtraction and correction by the upstream and downstream correction factors. Its conventional calibration method requires finding a suitable position in the aerosol flow path of the tester to connect a standard aerosol photometer, using filter materials with different filtration efficiencies as the test objects, and calibrating the filtration efficiency measurement results in a comparative manner. The calibration device used in this calibration method includes one or two standard aerosol photometers, necessary switching valves, connecting pipelines, and masks or filter materials that meet certain filtration efficiency requirements. Inevitably, such a calibration device will encounter problems such as pipeline memory effect, sampling flow disturbing the air flow operation of the tester, background subtraction and consistency of the standard aerosol photometer, and the traceability chain of the filtration efficiency calibration result being too complex during use. Although some institutions have proposed to calibrate the filtration efficiency and resistance in the form of standard filter membranes, there are still certain difficulties in the research and development of standard filter membranes, which cannot be achieved in a short time. As a consumable, continuous investment will also bring a certain cost pressure during use. Therefore, there is an urgent need for a calibration scheme that can resolve the above problems and contradictions. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention aims to provide an aerosol dilution method calibration device and calibration method for the particulate matter filtration efficiency of masks.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] An aerosol dilution method calibration device for the particulate matter filtration efficiency of masks, comprising an upstream pressure sampler, a flow-limiting capillary, a filter, a shunt, a downstream pressure sampler, a digital differential pressure gauge, an upstream pressure sampling port, a downstream pressure sampling port, an air outlet, an inner ring air inlet, a shunt pressure sampling port, and a resistance regulator;

[0006] The inside of the shunt is hollow, and its upper side surface is provided with a plurality of uniformly distributed dilution gas inlets, and the bottom is provided with an outlet; the top surface of the shunt is provided with a plurality of assembly holes, and each assembly hole is respectively inserted with a flow-limiting capillary; the inlets of the flow-limiting capillaries are higher than the top surface of the shunt, and the heights of the inlets of the flow-limiting capillaries are the same;

[0007] The lower part of the shunt is provided with a shunt pressure tapping port communicating with the inside of the shunt; a socket hole is provided at the center of the downstream pressure sensor, and the shunt is sleeved outside the socket hole through the socket hole. The shunt pressure tapping port is aligned with the downstream pressure tapping port on one side of the downstream pressure sensor; the lower part of the shunt is exactly in concave-convex fit with the inner side surface of the socket hole of the downstream pressure sensor; the bottom of the socket hole is an air outlet; a resistance regulator is provided on one side of the downstream pressure sensor. The resistance regulator extends into the downstream pressure sensor from the outside of the downstream pressure sensor and exactly corresponds to one of the dilution gas inlets of the shunt. The resistance regulator can move in and out and control the opening degree of the corresponding dilution gas inlet;

[0008] A central round hole is provided at the center of the filter, and the upper part of the shunt is sleeved through the central round hole;

[0009] The upstream pressure sensor includes an outer ring and an inner ring air inlet located inside the outer ring. The inner ring air inlet is sleeved between the first layer platform and the second layer platform and is located above the filter. The bottom surface of the outer ring is closely attached to the outer edge of the filter to ensure a sealed and firm connection; the upstream pressure tapping port is provided on the outer ring of the upstream pressure sensor and is communicated with the inner ring air inlet, and it should be in the same azimuth angle as the downstream pressure tapping port;

[0010] The high-pressure end and the low-pressure end of the digital differential pressure gauge are respectively connected to the upstream pressure tapping port and the downstream pressure tapping port.

[0011] Further, the upper part of the shunt is stepped and includes a first layer platform, a second layer platform and a third layer platform from top to bottom; a plurality of assembly holes are provided at the top of the first layer platform, and each assembly hole is inserted with a current-limiting capillary; the inlets of the current-limiting capillaries are higher than the top surface of the first layer platform; the top surface of the second layer platform is flush with the top surface of the downstream pressure sensor without obvious protrusions; the part of the shunt below the third layer platform and below is exactly in concave-convex fit with the inner side surface of the socket hole of the downstream pressure sensor; the filter is sleeved between the first layer platform and the second layer platform through the central round hole, and the bottom of the filter is closely attached to the top surface of the second layer platform to ensure a sealed and firm connection; the inner ring air inlet is sleeved between the first layer platform and the second layer platform and is located above the filter.

[0012] Further, a plurality of sealing washers are installed between the lower part of the shunt and the inner side surface of the socket hole of the downstream pressure sensor.

[0013] Further, the outer wall of the current-limiting capillary and the corresponding assembly hole in the shunt are sealed and fixed with sealant.

[0014] Furthermore, a sealing silica gel sleeve is sleeved outside between the first layer platform and the second layer platform, and the sealing silica gel sleeve is used to seal the gap between the filter, the inner ring air inlet and the shunt.

[0015] Further, a pressure-taking pipe is connected between the upstream pressure-taking port and the inner-ring air inlet.

[0016] Further, a silica gel gasket is provided on the outer bottom surface of the outer ring of the upstream pressure-taker. The silica gel gasket is pressed on the outer edge of the filter, and it is necessary to ensure that the surface of the filter is flattened without wrinkles.

[0017] The present invention also provides a calibration method using the above calibration device. The specific process is as follows:

[0018] I. Calibration:

[0019] After assembling the calibration device, a calibration device calibration system is respectively formed by connecting a standard flowmeter and a large-flow soot sampler. Among them, an upstream calibration connector is sleeved outside the inner-ring air inlet of the upstream pressure-taker, and the upstream calibration connector is connected to the standard flowmeter; the air outlet of the downstream pressure-taker is connected to a downstream calibration connector, and the downstream calibration connector is connected to the air inlet of the large-flow soot sampler;

[0020] Each flow-limiting capillary is numbered. Except for the first flow-limiting capillary, the inlets of the remaining flow-limiting capillaries are closed using rubber dust caps, and other dilution gas inlets except the dilution gas inlet that can be controlled by the resistance regulator are blocked, and then the following tests are carried out:

[0021] Adjust the sampling flow rate of the large-flow soot sampler to 75 L / min, observe the indication value of the digital differential pressure gauge, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter after stabilization; adjust the sampling flow rate of the large-flow soot sampler to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter under each flow rate condition, and establish a linear equation y = a1x + b1 between the two; when taking pressure at each sampling flow rate, the differential pressure value obtained at each sampling flow rate can be increased by 30 Pa in sequence through the adjustment of the resistance regulator; calculate the reference value of the filtration efficiency when using 1 flow-limiting capillary under the flow rate condition of 85 L / min:

[0022] Thereafter, tests on multiple flow-limiting capillaries are carried out. The inlets of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 flow-limiting capillaries are sequentially opened according to the serial number for the following tests. When testing, the inlets of all the remaining flow-limiting capillaries that are not allowed to be opened are closed using rubber dust caps:

[0023] Adjust the sampling flow rate of the high-volume dust sampler to 75 L / min, observe the indication value of the digital differential pressure gauge, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter after stabilization; adjust the sampling flow rate of the high-volume dust sampler to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter under each flow condition, and establish a linear equation y = a n x + b n , n = 2, 3…13; when taking pressure at each sampling flow rate, through the adjustment of the resistance regulator, the differential pressure value obtained at each sampling flow rate can be increased by 30 Pa in turn; calculate the reference filtration efficiency values when using different numbers of flow-limiting capillary tubes under the flow rate condition of 85 L / min respectively:

[0024]

[0025] n represents the number of open flow-limiting capillary tubes;

[0026] II. Testing:

[0027] Open all the dilution gas inlets of the shunt, connect the connected calibration device to the clamping mechanism of the face mask tester, and close the air inlets of all flow-limiting capillary tubes with rubber dust caps;

[0028] Start the calibration device. Under the corrected flow rate condition of 85 L / min, observe the filtration efficiency of the calibration device. If it is greater than or equal to 99.999%, it proves that the calibration device is in normal working condition, and the overall and local airtightness is good after the calibration device is connected;

[0029] Based on the reference filtration efficiency value and the required calibration point obtained during the calibration process, open the corresponding number of flow-limiting capillary tubes. Under the corrected flow rate condition of 85 L / min, observe and record the indication value of the digital differential pressure gauge and the filtration efficiency value of the calibration device, repeat 3 times, take the average value of the indication value of the digital differential pressure gauge and substitute it into the linear equation under the corresponding condition for aerosol flow calculation, subtract the calculated aerosol flow from the corrected actual working flow rate of 85 L / min, and then divide by the actual working flow rate and multiply by 100% to obtain the standard filtration efficiency value;

[0030] Subtract the calculated standard filtration efficiency value from the average value of the three filtration efficiency values to obtain the filtration efficiency calibration result, that is, the indication error of the filtration efficiency.

[0031] The beneficial effects of the present invention are as follows: By using the present invention, the disassembly and reconnection of the pipelines of the tester during the calibration process can be avoided, and the interference of the introduced standard device to the working conditions of the tester is minimized; during the calibration process, only the number of capillary tubes participating in current limiting needs to be changed for calibration, and a digital differential pressure gauge is used to record the upstream and downstream pressure differences, thus greatly simplifying the calibration process and saving calibration time; the calibration device does not involve standard devices and equipment with high value, greatly saving the calibration cost; the traceability chain of the calibration process of the filtration efficiency is clear, avoiding the introduction of more factors participating in the uncertainty evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a disassembled schematic diagram of the calibration device in Embodiment 1 of the present invention;

[0033] Figure 2 is a combined cross-sectional schematic diagram of the calibration device in Embodiment 1 of the present invention;

[0034] Figure 3 is a specific structural schematic diagram of the shunt in Embodiment 1 of the present invention;

[0035] Figure 4 is an external schematic diagram of the calibration device after partial assembly (excluding the digital differential pressure gauge) in Embodiment 1 of the present invention;

[0036] Figure 5 is a schematic diagram of the component connection for calibration of the calibration device in Embodiment 2 of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention will be further described below with reference to the accompanying drawings. It should be noted that this embodiment is based on the present technical solution and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to this embodiment.

[0038] Embodiment 1

[0039] This embodiment provides a calibration device for the aerosol dilution method of the particulate matter filtration efficiency of masks, as Figures 1-4 shown, including an upstream pressure sampler 1, a current-limiting capillary tube 2, a filter 3, a shunt 21, a sealing gasket 4, a downstream pressure sampler 5, a digital differential pressure gauge 6, an upstream pressure sampling port 7, a downstream pressure sampling port 8, an air outlet 9, an inner-ring air inlet 10, a resistance regulator 22, a first-layer platform 16, a second-layer platform 17, a third-layer platform 18, a shunt pressure sampling port 19, and a sealing silica gel sleeve 20.

[0040] The upper part of the flow divider 21 is stepped, and from top to bottom, it includes a first-layer platform 16, a second-layer platform 17, and a third-layer platform 18; the inside of the flow divider 21 is hollow, and there are four uniformly distributed dilution gas inlets 11 on the side, and an outlet at the bottom; there are a plurality of assembly holes (13 assembly holes in this embodiment) provided on the top of the first-layer platform 16, and each assembly hole is inserted with a flow-limiting capillary 2; the inlets of the flow-limiting capillaries 2 are higher than the top surface of the first-layer platform 16 (about 8 mm higher), and the heights of the inlets of the flow-limiting capillaries 2 are the same.

[0041] A plurality of layers of sealing washers 4 (3 layers in this embodiment) are installed at the lower part of the flow divider 21, and a flow divider pressure tapping port 19 communicating with the inside of the flow divider 21 is provided.

[0042] A socket hole is provided at the center of the downstream pressure sampler 5, and it is sleeved outside the flow divider 21 through the socket hole. The flow divider pressure tapping port 19 is aligned with the downstream pressure tapping port 8 provided on one side of the downstream pressure sampler 5. The top surface of the second-layer platform 17 is flush with the top surface of the downstream pressure sampler 5 without obvious protrusions; the part of the third-layer platform 18 and below of the flow divider 21 just fits into the inner side surface of the socket hole of the downstream pressure sampler 5 in a concave-convex manner; the bottom of the socket hole is an air outlet 9; a resistance regulator 22 is provided on one side of the downstream pressure sampler 5. The resistance regulator 22 extends into the downstream pressure sampler from the outside of the downstream pressure sampler 5 and just corresponds to one of the dilution gas inlets of the flow divider 21. The resistance regulator 22 can move in and out and control the opening degree of the corresponding dilution gas inlet.

[0043] In this embodiment, the resistance regulator 22 includes a piston rod that can move in and out and a spherical block provided at the end of the piston rod. By moving the piston rod, the relative position between the spherical block and the dilution gas inlet can be adjusted to control the opening degree of the dilution gas inlet.

[0044] A central round hole is provided at the center of the filter 3, and it is sleeved between the first-layer platform 16 and the second-layer platform 17 through the central round hole. The bottom of the filter 3 is closely attached to the top surface of the second-layer platform 17 to ensure a sealed and firm connection.

[0045] The upstream pressure sampler 1 includes an outer ring and an inner ring air inlet 10 located inside the outer ring. The inner ring air inlet 10 is sleeved between the first-layer platform 16 and the second-layer platform 17 and is located above the filter 3. The bottom surface of the outer ring is closely attached to the outer edge of the filter 3 to ensure a sealed and firm connection; the upstream pressure tapping port 7 is provided on the outer ring of the upstream pressure sampler 1 and is communicated with the inner ring air inlet 10, and it should be in the same azimuth angle as the downstream pressure tapping port 8;

[0046] The high-pressure end and the low-pressure end of the digital differential pressure gauge 6 are respectively connected to the upstream pressure tapping port 7 and the downstream pressure tapping port 8.

[0047] In this embodiment, the outer wall of the flow-limiting capillary 2 and the corresponding assembly hole in the diverter 21 are sealed and fixed with sealant.

[0048] In this embodiment, a sealing silica gel sleeve 20 is sleeved outside between the first-layer platform 16 and the second-layer platform 17, and the sealing silica gel sleeve 20 is used to seal the gaps between the filter 3, the inner-ring air inlet 10 and the diverter.

[0049] In this embodiment, the upstream pressure tapping port 7 and the inner-ring air inlet 10 are connected and communicated through a pressure tapping pipe.

[0050] In this embodiment, a silica gel gasket is provided on the outer-ring bottom surface of the upstream pressure transducer 1, and the silica gel gasket presses on the outer edge of the filter, and it is necessary to ensure that the filter surface is flattened without wrinkles.

[0051] Embodiment 2

[0052] The calibration device described in Embodiment 1 is essentially a flow-limiting aerosol diluter that meets the use requirements of a mask particulate matter filtration efficiency tester in terms of structural design. After it is connected to the clamping mechanism of the mask tester, the aerosol from the upstream of the mask tester follows the working airflow. A part of it enters the inner-ring air inlet and is directly introduced into the air outlet through the flow-limiting capillary. A part of it enters between the outer ring and the inner-ring inlet, is purified by the filter, and then enters the diverter through the dilution air inlet of the diverter, and is remixed with the airflow flowing out of the capillary, thereby diluting the upstream aerosol by a certain multiple. The reciprocal of this dilution multiple is subtracted by 1 and then multiplied by 100% to obtain the filtration efficiency standard value of this calibration device under certain flow conditions, and this dilution multiple can be obtained through the calculation of two-way flow rates. The total flow rate passing through the calibration device is the actual working flow rate of the mask tester, and this actual working flow rate participates in the calculation of the filtration efficiency standard value after being calibrated and confirmed. The flow rate through the flow-limiting capillary is calculated by collecting the pressure with a digital differential pressure gauge and then through the corresponding linear regression equation, and is calculated with the actual working flow rate to obtain the filtration efficiency standard value.

[0053] This embodiment provides a calibration method using the calibration device described in Embodiment 1, and the specific process is as follows:

[0054] I. Calibration:

[0055] The calibration process is to establish a linear regression equation of flow rate - pressure within the possible resistance range of the filter under the condition of different numbers of flow-limiting capillaries participating in the diversion, so as to monitor the differential pressure at both ends of the flow-limiting capillary to collect the aerosol flow rate, and further calculate the filtration efficiency standard value of the calibration device under this condition.

[0056] Such as Figure 5As shown, after assembling the calibration device, connect the standard flowmeter 12 and the high-flow soot sampler 13 respectively to form a calibration device calibration system; among them, an upstream calibration connector 14 is sleeved outside the inner-ring air inlet 10 of the upstream pressure tap 1, and the upstream calibration connector 14 is connected to the standard flowmeter 12; the air outlet 9 of the downstream pressure tap 5 is connected to the downstream calibration connector 15, and the downstream calibration connector 15 is connected to the air inlet of the high-flow soot sampler 13.

[0057] Label each flow-limiting capillary 2 with a serial number. Except for the first flow-limiting capillary, use a rubber dust cap to seal the inlets of the remaining flow-limiting capillaries, and block all other dilution gas inlets except the dilution gas inlet that can be controlled by the resistance regulator 22, and then conduct the following tests:

[0058] Adjust the sampling flow rate of the high-flow soot sampler 13 to 75 L / min, observe the indication value of the digital differential pressure gauge 6, and record the indication value of the digital differential pressure gauge 6 and the indication value of the standard flowmeter 12 after stabilization. Adjust the sampling flow rate of the high-flow soot sampler 13 to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge 6 and the indication value of the standard flowmeter 12 under each flow condition, and establish a linear equation y = a1x + b1 between the two; when taking pressure at each sampling flow rate, through the adjustment of the resistance regulator 22, the differential pressure value obtained at each sampling flow rate can be increased by about 30 Pa in turn; calculate the reference value of the filtration efficiency when using 1 root of the flow-limiting capillary 2 under the flow condition of 85 L / min:

[0059] Among them, 85 L / min is the actual working flow rate of the mask tester, that is, when the mask tester is calibrated at a flow rate of 85 L / min, the actual flow rate measured by the corresponding standard flowmeter.

[0060] Subsequently, conduct tests on multiple flow-limiting capillaries. Open the inlets of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 flow-limiting capillaries in sequence according to the serial number for the following tests. When testing, use a rubber dust cap to seal the inlets of all the remaining flow-limiting capillaries that are not allowed to be opened:

[0061] Adjust the sampling flow rate of the high-flow soot sampler 13 to 75 L / min, observe the indication value of the digital differential pressure gauge 6, and record the indication value of the digital differential pressure gauge 6 and the indication value of the standard flowmeter 12 after stabilization. Adjust the sampling flow rate of the high-flow soot sampler 13 to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge 6 and the indication value of the standard flowmeter 12 under each flow condition, and establish a linear equation y = an x + b n (n = 2, 3…13); When taking pressure at each sampling flow rate, through the adjustment of the resistance regulator 22, the differential pressure values obtained at each sampling flow rate can be increased by about 30 Pa in sequence; Calculate the reference filtration efficiency values when using different numbers of flow-limiting capillaries 2 under the flow rate condition of 85 L / min respectively:

[0062]

[0063] n represents the number of open flow-limiting capillaries.

[0064] II. Test:

[0065] Open all the dilution gas inlets of the diverter, connect the connected calibration device to the clamping mechanism of the mask tester, and close the air inlets of all flow-limiting capillaries with rubber dust caps;

[0066] Start the calibration device. Under the corrected flow rate condition of 85 L / min, observe the filtration efficiency of the calibration device. If it is greater than or equal to 99.999%, it proves that the calibration device is working properly, and the overall and local airtightness is good after the calibration device is connected;

[0067] Based on the reference filtration efficiency value and the required calibration point obtained during the calibration process, open the corresponding number of flow-limiting capillaries. Under the corrected flow rate condition of 85 L / min, observe and record the indication value of the digital differential pressure gauge 6 and the filtration efficiency value of the calibration device. Repeat 3 times, take the average value of the indication values of the digital differential pressure gauge 6 and substitute it into the linear equation corresponding to the condition for aerosol flow rate calculation. Subtract the calculated aerosol flow rate from the corrected actual working flow rate of 85 L / min, and then divide by the actual working flow rate and multiply by 100% to obtain the standard filtration efficiency value.

[0068] Subtract the calculated standard filtration efficiency value from the average value of the 3 filtration efficiency values to obtain the filtration efficiency calibration result, that is, the indication error of the filtration efficiency.

[0069] For those skilled in the art, various corresponding changes and deformations can be given according to the above technical solutions and concepts, and all these changes and deformations should be included within the protection scope of the claims of the present invention.

Claims

1. An aerosol dilution method calibration device for the particulate matter filtration efficiency of a mask, characterized in that, It includes an upstream pressure sampler, a flow-limiting capillary, a filter, a diverter, a downstream pressure sampler, a digital differential pressure gauge, an upstream pressure tapping, a downstream pressure tapping, an air outlet, an inner-ring air inlet, a diverter pressure tapping, and a resistance regulator; The inside of the diverter is hollow. It has a plurality of uniformly distributed dilution gas inlets on its upper side and an outlet at the bottom. The top surface of the diverter is provided with a plurality of assembly holes, and each assembly hole is inserted with a flow-limiting capillary. The inlets of the flow-limiting capillaries are higher than the top surface of the diverter, and the heights of the inlets of the flow-limiting capillaries are the same; The lower part of the diverter is provided with a diverter pressure tapping communicating with the inside of the diverter. A socket hole is provided in the center of the downstream pressure sampler, and the downstream pressure sampler is sleeved outside the diverter through the socket hole. The diverter pressure tapping is aligned with the downstream pressure tapping on one side of the downstream pressure sampler. The lower part of the diverter just fits into the inner side surface of the socket hole of the downstream pressure sampler in a concave-convex manner. The bottom of the socket hole is the air outlet. A resistance regulator is provided on one side of the downstream pressure sampler. The resistance regulator extends into the downstream pressure sampler from the outside of the downstream pressure sampler and just corresponds to one of the dilution gas inlets of the diverter. The resistance regulator can move in and out and control the opening degree of the corresponding dilution gas inlet; The center of the filter is provided with a central round hole, and the filter is sleeved on the upper part of the diverter through the central round hole; The upstream pressure sampler includes an outer ring and an inner-ring air inlet located inside the outer ring. The inner-ring air inlet is sleeved between the first layer platform and the second layer platform and is located above the filter. The bottom surface of the outer ring is closely attached to the outer edge of the filter to ensure a sealed and firm connection. The upstream pressure tapping is provided on the outer ring of the upstream pressure sampler and communicates with the inner-ring air inlet, and it should be in the same azimuth angle as the downstream pressure tapping; The high-pressure end and the low-pressure end of the digital differential pressure gauge are respectively connected to the upstream pressure tapping and the downstream pressure tapping; The upper part of the diverter is in a stepped shape and includes a first layer platform, a second layer platform, and a third layer platform from top to bottom. The top of the first layer platform is provided with a plurality of assembly holes, and each assembly hole is inserted with a flow-limiting capillary. The inlets of the flow-limiting capillaries are higher than the top surface of the first layer platform. The top surface of the second layer platform is flush with the top surface of the downstream pressure sampler without obvious protrusions. The part of the diverter below the third layer platform just fits into the inner side surface of the socket hole of the downstream pressure sampler in a concave-convex manner. The filter is sleeved between the first layer platform and the second layer platform through the central round hole, and the bottom of the filter is closely attached to the top surface of the second layer platform to ensure a sealed and firm connection. The inner-ring air inlet is sleeved between the first layer platform and the second layer platform and is located above the filter; A plurality of layers of sealing washers are installed between the lower part of the diverter and the inner side surface of the socket hole of the downstream pressure sampler.

2. The calibration device according to claim 1, wherein The outer wall of the flow-limiting capillary and the corresponding assembly hole in the diverter are sealed and fixed with sealant.

3. The calibration device according to claim 1, characterized in that, An outer sealing silica gel sleeve is sleeved between the first layer platform and the second layer platform, and the sealing silica gel sleeve is used to seal the gap between the filter, the inner-ring air inlet and the diverter.

4. The calibration device according to claim 1, characterized in that, The upstream pressure tapping and the inner-ring air inlet are connected by a pressure tapping pipe.

5. The calibration device according to claim 1, characterized in that, The bottom surface of the outer ring of the upstream pressure sampler is provided with a silica gel gasket, and the silica gel gasket is pressed on the outer edge of the filter, and it is necessary to ensure that the surface of the filter is flattened without wrinkles.

6. A calibration method using the calibration device according to any one of claims 1-5, characterized in that, The specific process is as follows: I. Calibration: After assembling the calibration device, connect the standard flowmeter and the large-flow dust sampler respectively to form a calibration device calibration system; among them, the outside of the inner ring air inlet of the upstream pressure sampler is sleeved with an upstream calibration connector, and the upstream calibration connector is connected to the standard flowmeter; the air outlet of the downstream pressure sampler is connected to the downstream calibration connector, and the downstream calibration connector is connected to the air inlet of the large-flow dust sampler; Mark each flow-limiting capillary with a serial number. Except for the first flow-limiting capillary, use a rubber dust cap to close the inlets of the remaining flow-limiting capillaries, and block all other dilution gas inlets except the dilution gas inlet that can be controlled by the resistance regulator, and then conduct the following tests: Adjust the sampling flow rate of the high-volume smoke sampler to 75 L / min, observe the indication value of the digital differential pressure gauge, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter after stabilization; adjust the sampling flow rate of the high-volume smoke sampler to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter under each flow rate condition, and establish a linear equation y = a1x + b1 between the two; when taking pressure at each sampling flow rate, the differential pressure value obtained at each sampling flow rate can be increased by 30 Pa successively through the adjustment of the resistance regulator; calculate the reference value of the filtration efficiency when using 1 limiting capillary tube under the flow rate condition of 85 L / min: ; Subsequently, conduct tests on multiple flow-limiting capillaries. Open the inlets of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 flow-limiting capillaries in sequence according to the serial number for the following tests. When testing, use a rubber dust cap to close the inlets of all the remaining flow-limiting capillaries that are not allowed to be opened: Adjust the sampling flow rate of the high-volume dust sampler to 75 L / min, observe the indication value of the digital differential pressure gauge, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter after stabilization; adjust the sampling flow rate of the high-volume dust sampler to 80 L / min, 85 L / min, 90 L / min, 95 L / min, and 100 L / min respectively, and record the indication value of the digital differential pressure gauge and the indication value of the standard flowmeter under each flow rate condition, and establish a linear equation y = a n x + b n , n = 2, 3…13; when taking pressure at each sampling flow rate, the differential pressure value obtained at each sampling flow rate can be increased by 30 Pa in turn through the adjustment of the resistance regulator; calculate the reference filtration efficiency values when using different numbers of flow-limiting capillary tubes under the flow rate condition of 85 L / min respectively: n represents the number of opened flow-limiting capillaries; II. Test: Open all the dilution gas inlets of the shunt, connect the assembled calibration device to the clamping mechanism of the mask tester, and use a rubber dust cap to close the air inlets of all the flow-limiting capillaries; Start the calibration device. Under the condition of a corrected flow rate of 85 L / min, observe the filtration efficiency of the calibration device. If it is greater than or equal to 99.999%, it proves that the calibration device is in normal working condition, and the overall and local airtightness is good after the calibration device is connected; Based on the filtration efficiency reference value and the required calibration points obtained during the calibration process, open the corresponding number of flow-limiting capillaries. Under the condition of a corrected flow rate of 85 L / min, observe and record the indication value of the digital differential pressure gauge and the filtration efficiency value of the calibration device. Repeat 3 times, take the average value of the indication value of the digital differential pressure gauge and substitute it into the linear equation of the corresponding condition for aerosol flow calculation. Subtract the calculated aerosol flow from the corrected actual working flow rate of 85 L / min, and then divide by the actual working flow rate and multiply by 100% to obtain the filtration efficiency standard value; Subtract the calculated filtration efficiency standard value from the average value of the 3 filtration efficiency values to obtain the filtration efficiency calibration result, that is, the indication error of the filtration efficiency.

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