An aerosol dilution system, dilution method and photometer calibration device

Abstract

The present invention discloses an aerosol dilution system, a dilution method and a photometer calibration device. The dilution system includes a mixing and dilution device, a first dilution gas path, a mixed gas path and a buffer tank; the mixing and dilution device includes a mixing chamber and a first dilution gas inlet, a mixed gas inlet and an air outlet that are communicated with the mixing chamber; the first dilution gas path is connected to the first dilution gas inlet for providing a first path of dilution gas to the mixing chamber; the mixed gas path is connected to the mixed gas inlet, and the mixed gas path is respectively connected to a second dilution gas path and an aerosol gas path. The second path of dilution gas and the aerosol are mixed and flow into the mixing chamber through the mixed gas inlet under the action of the negative pressure in the inner cavity of the mixing and dilution device; the buffer tank is connected to the air outlet through a pipeline; the flow rates of the first dilution gas path, the second dilution gas path and the aerosol gas path are adjustable. This dilution system can achieve an accurate dilution ratio, with precise adjustment of the dilution ratio, effectively improving the calibration accuracy of the photometer.

Description

Technical Field

[0001] The present invention relates to the technical field of aerosol detection, and particularly relates to an aerosol dilution system, a dilution method, and a photometer calibration device. Background Art

[0002] An aerosol is a colloidal dispersion system formed by dispersing and suspending solid or liquid small particles in a gas medium, also known as a gas dispersion system. Its dispersed phase is solid or liquid small particles with a size of 0.001 - 100 micrometers, and the dispersion medium is a gas. Aerosols have extensive applications in medicine, environmental science, and military science.

[0003] In many studies on particulate matter measurement and particulate matter concentration in the air, an aerosol photometer is used to detect the particulate matter mass concentration in the monitored environment. Currently, in the production and detection of filter materials such as masks and meltblown fabrics, aerosol particles are used to detect the filtration efficiency of the filter materials. An aerosol photometer is a simple optical measurement system. By establishing the relationship between the aerosol mass concentration and the photoelectric signal of a photodetector, real-time detection of the aerosol mass concentration can be achieved.

[0004] The calibration of a photometer requires a precise photometer calibration device: the aerosol concentration generated can be controlled within a certain range (0 - 120 μg / L), the mixture is uniform, and its concentration stability is good.

[0005] As a key structure of a photometer calibration device, an aerosol dilution system can directly affect the accuracy and stability of photometer calibration. The aerosol dilution system can also be used together with an aerosol detection device, such as a condensation particle counter (CPC), an optical particle counter (OPC), a spectrometer, or other types of particle monitoring devices known in the art (including virtual impactors, cascade impactors, etc.).

[0006] Common aerosol dilution systems in the prior art generally mix one-way dilution gas and one-way aerosol directly in a mixing box. The dilution ratio of the aerosol is not easy to adjust, the mixture is not uniform, and it affects the calibration accuracy of the photometer.

[0007] The above information disclosed in this background art is only used to increase the understanding of the background art of the present application. Therefore, it may include prior art that is not known to those of ordinary skill in the art. Summary of the Invention

[0008] In view of the problems pointed out in the background art, the present invention proposes an aerosol dilution system, a dilution method, and a photometer calibration device. This dilution system can achieve an accurate dilution ratio, the dilution ratio can be adjusted precisely, and the calibration accuracy of the photometer can be effectively improved.

[0009] To achieve the above-mentioned invention objectives, the present invention adopts the following technical solutions:

[0010] The present invention provides an aerosol dilution system, comprising:

[0011] a mixing and dilution device, which comprises a mixing chamber, a first dilution gas inlet, a mixed gas inlet and an air outlet that are communicated with the mixing chamber;

[0012] a first dilution gas path, which is connected to the first dilution gas inlet and is used for providing a first path of dilution gas into the mixing chamber;

[0013] a mixed gas path, which is connected to the mixed gas inlet, the mixed gas path is respectively connected to a second dilution gas path and an aerosol gas path, the second path of dilution gas in the second dilution gas path and the aerosol in the aerosol gas path are mixed, and under the action of the negative pressure in the inner cavity of the mixing and dilution device, they flow into the mixing chamber through the mixed gas inlet;

[0014] a buffer tank, which is connected to the air outlet through a pipeline;

[0015] wherein, the flow rates of the first dilution gas path, the second dilution gas path and the aerosol gas path are adjustable.

[0016] In some embodiments of the present application, the first dilution gas inlet and the air outlet are relatively arranged at two ends of the mixing and dilution device;

[0017] a communication section communicating with the first dilution gas inlet and the mixing chamber is arranged in the inner cavity of the mixing and dilution device, and the mixed gas inlet is communicated with the communication section;

[0018] an adjusting rod is arranged on the side wall of the mixing and dilution device, one end of the adjusting rod extends into the communication section and faces the mixed gas inlet, and a tapered fit is formed between the end of the adjusting rod and the air outlet end of the mixed gas inlet, and the inflow amount of the mixed gas in the mixed gas path is adjusted by the movement of the adjusting rod.

[0019] In some embodiments of the present application, an acceleration section is arranged in the inner cavity of the mixing and dilution device, one end of the acceleration section is communicated with the first dilution gas inlet, and the other end is communicated with the communication section.

[0020] In some embodiments of the present application, the mixing chamber has a gradually expanding structure from the communication section to the air outlet direction.

[0021] In some embodiments of the present application, the second dilution gas path and the aerosol gas path are connected to the mixed gas path through a tee structure, and a flow rate detection device is arranged on the pipeline between the tee structure and the mixed gas inlet.

[0022] In some embodiments of the present application, the first dilution gas path and the aerosol gas path are provided with clean gas by the same gas source system, and the second dilution gas path draws clean gas from the atmosphere through a dryer and a filter.

[0023] The present invention also provides an aerosol dilution method, comprising:

[0024] providing an aerosol by an aerosol gas path, providing a first dilution gas by a first dilution gas path, and providing a second dilution gas by a second dilution gas path;

[0025] performing jet mixing on the aerosol and the dilution gas by using a mixing and dilution device;

[0026] The aerosol and the second dilution gas are mixed in a tee structure and then flow into the inner cavity of the mixing and dilution device. The first dilution gas directly flows into the inner cavity of the mixing and dilution device. During the process of the first dilution gas flowing towards the air outlet of the mixing and dilution device, a negative pressure is generated, sucking the mixture of the aerosol and the second dilution gas into the inner cavity of the mixing and dilution device, so that the first dilution gas and the mixture are mixed in the inner cavity of the mixing and dilution device;

[0027] The mixed gas then flows through the air outlet to a buffer tank downstream.

[0028] The present invention also provides a photometer calibration device, comprising:

[0029] a gas source system, a calibration system, and the aerosol dilution system as described above;

[0030] The gas source system provides clean gas to the first dilution gas path and the aerosol gas path;

[0031] The calibration system includes a sampling chamber, which is connected with a photometer and a photometer to be calibrated, and the buffer tank is communicated with the sampling chamber through a pipeline.

[0032] In some embodiments of the present application, the calibration system includes an upper fixture chamber and a lower fixture chamber. The upper fixture chamber and the lower fixture chamber move relative to each other to dock and enclose the sampling chamber. A weighing filter membrane fixture and a shunt ring are arranged between the upper fixture chamber and the lower fixture chamber. The photometer and the photometer to be calibrated are connected to the shunt ring through pipelines, and the air outlet end of the lower fixture chamber is connected with an air extraction pump.

[0033] In some embodiments of the present application, the gas source system includes an air compressor, a steam drum, a cold dryer, a dryer, and a high-efficiency filter connected in sequence.

[0034] Compared with the prior art, the advantages and positive effects of the present invention are:

[0035] In the aerosol dilution system disclosed in this application, two dilution gases and one aerosol are mixed. One of the dilution gases and the aerosol are inhaled under the negative pressure of the mixing diluter. When adjusting the dilution ratio, the first dilution gas path and the aerosol gas path play a major adjustment role, and the second dilution gas path plays an auxiliary fine-tuning role, which helps to achieve accurate flow ratio matching to obtain an accurate dilution ratio, and the adjustable range of the dilution ratio is wide.

[0036] The dilution gas and the aerosol are jet-mixed by the mixing diluter, and the aerosol is evenly mixed and diluted. Further mixing can be carried out in the buffer tank. On the one hand, the mixing uniformity is further improved, and on the other hand, the influence of airflow fluctuation on the stability of the airflow in the photometer calibration system can be avoided, and the calibration accuracy is improved.

[0037] The flow rates of the first dilution gas path, the second dilution gas path, and the aerosol gas path are adjustable, which can accurately control the mixing dilution ratio and meet the requirements of different calibration experiments.

[0038] This aerosol dilution system can determine the dilution ratio of the dilution system basically in real time, constantly or periodically, so that the generated aerosol concentration can be controlled (0 - 120 μg / L), and the aerosol generation concentration is stable.

[0039] During the whole dilution and calibration process, the aerosol is always flowing dynamically, which can effectively prevent adverse effects such as sudden increase and sudden drop of the aerosol concentration when it is stationary, and ensure the calibration accuracy.

[0040] After reading the specific embodiments of the present invention in conjunction with the drawings, other features and advantages of the present invention will become clearer. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic structural diagram of a photometer calibration device according to an embodiment;

[0043] Figure 2 It is a schematic structural diagram of a mixing diluter according to an embodiment;

[0044] Figure 3 It is a top view of a mixing diluter according to an embodiment;

[0045] Figure 4 For Figure 3 The sectional view taken along the line A - A in

[0046] Figure 5 Structural schematic diagram of a three-way structure according to an embodiment;

[0047] Figure 6 is Figure 5 Cross-sectional view taken along line B-B in

[0048] Reference numerals:

[0049] 100 - Gas source system;

[0050] 101 - Air compressor, 102 - Steam drum, 103 - Refrigerated dryer, 104 - Desiccant, 105 - High-efficiency filter;

[0051] 200 - Dilution system;

[0052] 201 - First flow regulating valve, 202 - First temperature measuring sensor, 203 - First differential pressure sensor, 204 - First orifice flowmeter, 205 - Mixing and dilution device, 2051 - First dilution gas inlet, 2052 - Adjusting rod, 2053 - Connecting section, 2054 - Conical structure, 2055 - Acceleration section, 2056 - Mixed gas inlet, 2057 - Mixing chamber, 2058 - Outlet, 206 - Second dilution gas filter, 207 - Second temperature measuring sensor, 208 - Second orifice differential pressure sensor, 209 - Second flow regulating valve, 210 - Second orifice flowmeter, 211 - Third orifice flowmeter, 212 - Third orifice differential pressure sensor, 213 - Third temperature measuring sensor, 214 - Mixing three-way, 2141 - Main pipeline, 2142 - Branch pipeline, 215 - Electrometer, 216 - Orifice restrictor, 217 - Aerosol regulating valve, 218 - Aerosol generator regulating valve, 219 - Pressure gauge, 220 - Spray head, 221 - Aerosol generator liquid storage tank, 222 - Exhaust gas filter, 223 - Pressure balance filter, 224 - Buffer tank, 225 - Second dilution gas dryer;

[0053] 300 - Calibration system;

[0054] 301 - Two-position five-way solenoid valve, 302 - Clamping cylinder, 303 - Holder bracket, 304 - Shunt ring, 305 - Upper clamp cavity, 306 - Weighing filter membrane clamp, 307 - Photometer, 308 - Photometer to be calibrated, 309 - Pump front filter, 310 - Pump front temperature measuring sensor, 311 - Pump front orifice flowmeter, 312 - Pump front differential pressure sensor, 313 - Air extraction pump, 314 - Lower clamp cavity;

[0055] S1 - First dilution gas path;

[0056] S2 - Second dilution gas path;

[0057] S3 - Aerosol gas path;

[0058] S4 - Mixed gas path;

[0059] Q1 - First dilution gas;

[0060] Q2 - Second dilution gas;

[0061] Q3 - Aerosol;

[0062] P - Mixed gas. Detailed implementation manner

[0063] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0064] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0065] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "plurality" is two or more.

[0066] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0067] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly under and obliquely under the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0068] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described hereinafter. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0069] This embodiment discloses a photometer calibration device, which calibrates a photometer by using an aerosol with a specific concentration.

[0070] Referring to Figure 1 , the photometer calibration device includes a gas source system 100, an aerosol dilution system 200, and a calibration system 300.

[0071] The gas source system 100 is used to provide a gas source for the aerosol dilution system 200 and the calibration system 300.

[0072] The aerosol dilution system 200 is used to dilute the aerosol to obtain an aerosol with a certain concentration for use by the calibration system 300.

[0073] The aerosol dilution system 200 mainly includes a mixing and dilution device 205, a first dilution gas path S1, a mixed gas path S4, a buffer tank 224, etc.

[0074] The mixing and dilution device 205 is the core key component of the aerosol dilution system 200, and is used to mix and dilute the dilution gas and the aerosol. The aerosol after mixing and dilution then flows into the buffer tank 224 for use by the photometer calibration system 300.

[0075] There are three paths for the gas entering the mixing and dilution device 205, namely the first dilution gas path, the second dilution gas path, and the aerosol. The first dilution gas is provided by the first dilution gas path S1, the second dilution gas is provided by the second dilution gas path S2, and the aerosol is provided by the aerosol gas path S3.

[0076] The second dilution gas path S2 and the aerosol gas path S3 are both connected to the mixed gas path S4. After the second dilution gas and the aerosol are mixed in the mixed gas path S4, they then flow into the mixing and dilution device 205 to be secondarily mixed and diluted with the first dilution gas.

[0077] Inside the mixing and dilution device 205, there is a mixing chamber 2057, and on its wall, there are a first dilution gas inlet 2051, a mixed gas inlet 2056, and an air outlet 2058 that communicate with the mixing chamber 2057.

[0078] The first dilution gas path S1 is connected to the first dilution gas inlet 2051, and the dilution gas in the first dilution gas path S1 flows into the mixing chamber 2057 through the first dilution gas inlet 2051.

[0079] The mixed gas path is connected to the mixed gas inlet 2056. The dilution gas in the second dilution gas path S2 and the aerosol in the aerosol gas path S3 are mixed and, under the negative pressure of the inner cavity of the mixing and dilution device 205, flow into the mixing chamber 2057 through the mixed gas inlet 2056.

[0080] After the first dilution gas and the mixed gas are mixed and diluted in the mixing chamber 2057, they then flow through the air outlet 2058 to the buffer tank 224.

[0081] Through the mixing and dilution device 205, the dilution gas and the aerosol are jet - mixed. The aerosol is mixed and diluted evenly, and can be further mixed in the buffer tank 224. On the one hand, it further improves the mixing uniformity, and on the other hand, it can avoid the influence of air - flow fluctuations on the air - flow stability in the photometer calibration system 300 and improve the calibration accuracy.

[0082] The flow rates of the first dilution gas path S1, the second dilution gas path S2, and the aerosol gas path S3 are adjustable, which can accurately control the mixing and dilution ratio to meet the requirements of different calibration experiments.

[0083] Two paths of dilution gas and one path of aerosol are used for mixing, and one of the dilution gas and the aerosol is inhaled under the negative pressure of the mixing chamber 2057. When adjusting the dilution ratio, the first dilution gas path S1 and the aerosol gas path S3 play a major adjustment role, and the second dilution gas path S2 plays an auxiliary fine - tuning role, which helps to achieve an accurate flow rate ratio to obtain an accurate dilution ratio, and the adjustable range of the dilution ratio is wide.

[0084] During the entire dilution and calibration process, the aerosol is always flowing dynamically, which can effectively prevent adverse effects such as sudden increase or decrease in concentration when the aerosol is stationary, thereby ensuring calibration accuracy.

[0085] In some embodiments of the present application, refer to Figures 2 to 4 The first dilution gas inlet 2051 and the gas outlet 2058 are relatively arranged at the two ends of the mixer and diluter 205; a connecting section 2053 connected with the first dilution gas inlet 2051 and the mixing chamber 2057 is provided in the inner cavity of the mixer and diluter 205, and the connecting section 2053 is vertically arranged between the first dilution gas inlet 2051 and the mixing chamber 2057, and the mixed gas inlet 2056 is arranged at the middle position of the side wall of the mixer and diluter 205 and is connected with the connecting section 2053.

[0086] The first dilution gas flows in through the first dilution gas inlet 2051, and passes through the connecting section 2053 during the flow toward the mixing chamber 2057, generating negative pressure at the connecting section 2053. By utilizing the Venturi principle, the mixed gas formed by the second dilution gas and the aerosol in the mixed gas path S4 is sucked in through the mixed gas inlet 2056, flows toward the mixing chamber 2057 together with the first dilution gas, and then flows out through the gas outlet 2058.

[0087] An adjusting rod 2052 is provided on the side wall of the mixer and diluter 205. The adjusting rod 2052 is arranged opposite to the mixed gas inlet 2056. One end of the adjusting rod 2052 extends into the connecting section 2053 and faces the mixed gas inlet 2056. The end of the adjusting rod 2052 and the gas outlet end of the mixed gas inlet 2056 are conically matched. The movement of the adjusting rod 2052 is used to adjust the mixed gas inflow into the mixed gas path S4.

[0088] In some embodiments of the present application, an acceleration section 2055 is provided in the inner cavity of the mixer and diluter 205, one end of the acceleration section 2055 is connected to the first dilution gas inlet 2051, and the other end is connected to the connecting section 2053. The acceleration section 2055 accelerates the inflowing first dilution gas to improve the effect of generating negative pressure at the connecting section 2053. At the same time, the high-speed flowing first dilution gas has a jet impact on the mixed gas flowing in from the mixed gas inlet 2056, thereby improving the mixing effect.

[0089] In some embodiments of the present application, the first dilution gas inlet 2051 and the acceleration section 2055 are transitionally connected by a tapered conical structure 2054, which plays a role in guiding the airflow.

[0090] In some embodiments of the present application, the mixing chamber 2057 has a gradually expanding structure from the connecting section 2053 to the gas outlet 2058, which improves the mixing effect of the first dilution gas and the mixed gas and also facilitates the mixed and diluted gas to flow downstream through the gas outlet 2058.

[0091] In some embodiments of the present application, the second dilution gas path S2 and the aerosol gas path S3 are connected to the mixed gas path S4 through a tee structure 214. A flow rate detection device, marked as the third flow rate detection device, is provided on the pipeline between the tee structure 214 and the mixed gas inlet 2056 for detecting the flow rate of the mixed gas.

[0092] The third flow rate detection device includes a third orifice flowmeter 211, a third orifice differential pressure sensor 212, and a third temperature measurement sensor 213. The third orifice differential pressure sensor 212 is used to measure the differential pressure before and after the orifice plate, and the third temperature measurement sensor 213 is used to measure the temperature before the orifice plate.

[0093] The tee structure 214 is as Figure 5 and Figure 6 shown. The tee structure 214 includes a main pipeline 2141 with both ends penetrating and a branch pipeline 2142 inserted on the main pipeline 2141. The branch pipeline 2142 has an L-shaped structure and is arranged on the side wall of the main pipeline 2141. The outlet end of the branch pipeline 2142 extends along the gas flow direction in the main pipeline 2141.

[0094] The inner diameter of the main pipeline 2141 is larger than that of the branch pipeline 2142. One end of the main pipeline 2141 is connected to the aerosol gas path S3, the other end is connected to the mixed gas path S4, and the branch pipeline 2142 is connected to the second dilution gas path S2.

[0095] The aerosol and the second dilution gas are mixed in the main pipeline 2141 and then flow to the mixed gas path S4 together.

[0096] In some embodiments of the present application, a first flow rate regulating valve 201 and a first flow rate detection device are provided on the first dilution gas path S1.

[0097] The first flow rate regulating valve 201 is used to regulate the flow rate of the first dilution gas.

[0098] The first flow rate detection device is used to detect the flow rate of the first dilution gas and includes a first orifice flowmeter 204, a first orifice differential pressure sensor 203, and a first temperature measurement sensor 202. The first orifice differential pressure sensor 203 is used to measure the differential pressure before and after the orifice plate, and the first temperature measurement sensor 202 is used to measure the temperature before the orifice plate.

[0099] In some embodiments of the present application, a second dilution gas dryer 225, a second dilution gas filter 206, a second flow rate regulating valve 209, and a second flow rate detection device are provided on the second dilution gas path S2.

[0100] The second flow rate regulating valve 209 is used to regulate the flow rate of the second dilution gas.

[0101] The second flow rate detection device is used to detect the flow rate of the second dilution gas, and it includes a second orifice flowmeter 210, a second orifice differential pressure sensor 208, and a second temperature measuring sensor 207. The second orifice differential pressure sensor 208 is used to measure the differential pressure before and after the orifice plate, and the second temperature measuring sensor 207 is used to measure the temperature before the orifice plate.

[0102] Under the negative pressure generated by the mixing and diluting device 205, the extraction air passes through the second dilution gas dryer 225 and the second dilution gas filter 206 to filter out moisture and particulate matter in the air, and then passes through the second flow rate regulating valve 209 and the second flow rate detection device to be mixed with the aerosol in the tee structure 214.

[0103] In some embodiments of the present application, the aerosol gas path S3 includes an aerosol generator regulating valve 218, a spray head 220, a liquid storage tank 221, a residual gas filter 222, an aerosol regulating valve 217 (a ball valve is used), an orifice restrictor 216, and an aerosol electrometer 215. The electrometer 215 is provided between the tee structure 214 and the orifice restrictor 216.

[0104] The clean compressed gas flows through the aerosol generator regulating valve 218 to the spray head 20. The spray head 220 is immersed in the solution in the liquid storage tank 221 of the aerosol generator. Under the action of the compressed gas, the spray head 220 generates aerosol. The generated aerosol is divided into two paths. One path of aerosol is discharged through the residual gas filter 222, and the other path of aerosol flows to the tee structure 214 through the aerosol regulating valve 217 and the orifice restrictor 216 under the action of the negative pressure generated by the mixing and diluting device 205 to be mixed with the second dilution gas. The mixed gas flows into the mixing and diluting device 205 through the mixed gas path S4 and the third flow rate detection device.

[0105] An example of calculating the dilution ratio is as follows:

[0106] The electrometer 215 measures that the aerosol concentration passing through the orifice restrictor 216 is 1 μg / L. The first orifice flowmeter 204 measures that the flow rate of the first dilution gas is 100 L / min. The adjusting rod 2052 of the mixing and dilution device is adjusted to make the flow rate of the third orifice flowmeter 211 1 L / min. The second flow regulating valve 209 is adjusted to make the flow rate of the second dilution gas passing through the second orifice flowmeter 210 0.5 L / min. Then the aerosol flow rate entering the tee structure 214 through the orifice restrictor 216 is 1 - 0.5 = 0.5 L / min. Then the concentration of the aerosol entering the mixing and dilution device 205 is 0.5 * 1 / 1 = 0.5 μg / L. The concentration after entering the buffer tank 224 after passing through the mixing and dilution device 205 is: 0.5 * 1 / (100 + 1) = 0.00495 μg / L. At this time, the dilution ratio is 1:0.00495, close to a dilution ratio of 202 times. A larger dilution ratio can be obtained by adjusting the adjusting rod 2052 and the second flow regulating valve 209.

[0107] In this embodiment, the dilution system can determine the dilution ratio of the dilution system basically in real time, constantly or periodically, so that the aerosol concentration generated can be controlled within a certain range (0 - 120 μg / L), and the aerosol generation concentration is stable.

[0108] In some embodiments of the present application, a pressure balance filter 223 is connected to the buffer tank 224. After the gas flowing out of the mixing and dilution device 205 flows into the buffer tank 224, a certain positive pressure is presented in the buffer tank 224. The pressure balance filter 223 is used to balance the air pressure in the buffer tank 224, which helps to improve the air pressure stability in the calibration system 300 and improve the calibration accuracy.

[0109] In some embodiments of the present application, the first dilution gas path S1 and the aerosol gas path S3 are provided with clean compressed gas by the same gas source system 100, and the second dilution gas path S2 draws clean gas from the atmosphere through a dryer and a filter.

[0110] The gas paths led out from the gas source system 100 are few and the air flow is stable, which helps to improve the stability and accuracy of the whole system.

[0111] In some embodiments of the present application, the gas source system 100 includes an air compressor 101, a steam drum 102, a cold dryer 103, a dryer 104, and a high-efficiency filter 105 connected in sequence.

[0112] The air compressor 101 pumps air into the steam drum 102. After the air pressure reaches a certain pressure, the pumping stops. The compressed gas passes through the cold dryer 103 to remove the water vapor in the gas, then passes through the dryer 104 to adsorb the small water droplets that have not been removed, and then passes through the high-efficiency filter 105 to filter out the particulate matter in the gas source to obtain clean compressed gas.

[0113] The clean compressed air is divided into three paths. One path is supplied to the first dilution gas path S1, one path is supplied to the aerosol gas path S3, and one path is supplied to the calibration system 300.

[0114] In some embodiments of the present application, the calibration system 300 includes an upper clamp cavity 305 and a lower clamp cavity 314. The upper clamp cavity 305 and the lower clamp cavity 314 move relative to each other to dock and enclose a sampling cavity. The vertical relative movement of the upper clamp cavity 305 and the lower clamp cavity 314 is realized by a clamping cylinder 302. A path of compressed air led out from the gas source system 100 provides power for the clamping cylinder 302. A weighing filter membrane clamp 306 and a shunt ring 304 are arranged between the upper clamp cavity 305 and the lower clamp cavity 314. The photometer 307 and the calibrated photometer 308 are connected to the shunt ring 304 through pipelines. The air outlet end of the lower clamp cavity 314 is connected to an air extraction pump 313. Both the photometer 307 and the calibrated photometer 308 are respectively equipped with their own power sources.

[0115] In the calibration system 300, the compressed air is connected to a five-port two-position solenoid valve 301 to control the action of the clamping cylinder 302, and then control the up and down movement of the upper clamp cavity 305. The clamping cylinder 302 and the lower clamp cavity 314 are respectively fixed on the upper and lower parts of the holder bracket 303. The shunt ring 304 and the weighing filter membrane clamp 306 are respectively placed in the upper clamp cavity 305 and the lower clamp cavity 314 from top to bottom. Two air outlet nozzles are symmetrically arranged on the shunt ring 304, and the air outlet nozzles are respectively connected to a precision aerosol photometer 307 and a calibrated aerosol photometer 308. The lower end of the lower clamp cavity 314 is sequentially connected to a pump front filter 309, a pump front orifice flowmeter 311, and an air extraction pump 313. A pump front temperature sensor 310 and a pump front orifice differential pressure sensor 312 are respectively arranged at the front end of the orifice plate and on both sides of the orifice plate of the pump front orifice flowmeter 311. The pump front temperature sensor 310 measures the temperature in front of the orifice plate of the pump front orifice flowmeter 311, and the pump front orifice differential pressure sensor 312 measures the pressure difference before and after the orifice plate of the pump front orifice flowmeter 311, so as to calculate the air extraction flow rate of the air extraction pump 313. By adjusting the rotation speed of the air extraction pump 313, the flow rate measured by the pump front orifice flowmeter 311 is made to be consistent with the sampling flow rates of the precision aerosol photometer 307 and the calibrated aerosol photometer 308.

[0116] The buffer tank 224 is connected to the sampling chamber in the calibration system 300 through a pipeline. The aerosol in the buffer tank 224 flows into the chamber formed by the upper fixture chamber 305, the lower fixture chamber 314, the weighing filter membrane fixture 306, and the shunt ring 304 (i.e., the sampling chamber) under the action of the air extraction pump 313, the precision aerosol photometer 307, and the aerosol photometer to be calibrated 308. Since the air extraction flow rates of the air extraction pump 313, the precision aerosol photometer 307, and the aerosol photometer to be calibrated 308 are the same, the aerosol in the chamber is evenly distributed. When calibrating the photometer, a weighing filter membrane is placed in the weighing filter membrane fixture 306, and the air extraction pump 313, the precision aerosol photometer 307, and the aerosol photometer to be calibrated 308 extract air simultaneously. Since the aerosol is evenly distributed, the total amount of aerosol entering the precision aerosol photometer 307 and the aerosol photometer to be calibrated 308 and the total amount of aerosol captured by the filter membrane can ensure good consistency. The indication concentration of the precision aerosol photometer 307 is used to calibrate the aerosol photometer to be calibrated 308, and the aerosol captured by the filter membrane can be used as the traceability of the calibration result.

[0117] In some embodiments of the present application, the Figure 1 system shown is used for aerosol dilution, and the dilution method is as follows:

[0118] The aerosol is provided by the aerosol gas path, the first dilution gas is provided by the first dilution gas path S1, and the second dilution gas is provided by the second dilution gas path S2;

[0119] The jet mixer 205 is used to mix the aerosol and the dilution gas jet - style;

[0120] The aerosol and the second dilution gas are mixed in the three - way structure 214 and then flow into the inner cavity of the jet mixer 205. The first dilution gas directly flows into the inner cavity of the jet mixer 205. During the process of the first dilution gas flowing towards the air outlet of the jet mixer 205, a negative pressure is generated, sucking the mixture of the aerosol and the second dilution gas into the inner cavity of the jet mixer 205, so that the first dilution gas and the mixture are mixed in the inner cavity of the jet mixer 205;

[0121] The mixed gas then flows through the air outlet to the downstream buffer tank 224.

[0122] In the description of the above - mentioned embodiments, the specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0123] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An aerosol dilution system, characterized in that, Comprising: A mixing and diluting device, which includes a mixing chamber, a first dilution gas inlet, a mixed gas inlet, and an air outlet that are communicated with the mixing chamber; A first dilution gas path, which is connected to the first dilution gas inlet and is used to provide a first path of dilution gas to the mixing chamber; A mixed gas path, which is connected to the mixed gas inlet. The mixed gas path is respectively connected to a second dilution gas path and an aerosol gas path. The second path of dilution gas in the second dilution gas path and the aerosol in the aerosol gas path are mixed and flow into the mixing chamber through the mixed gas inlet under the action of the negative pressure in the inner cavity of the mixing and diluting device; A buffer tank, which is connected to the air outlet through a pipeline; Wherein, the flow rates of the first dilution gas path, the second dilution gas path, and the aerosol gas path are adjustable; The first dilution gas inlet and the air outlet are relatively arranged at both ends of the mixing and diluting device; A communication section that is communicated with the first dilution gas inlet and the mixing chamber is provided in the inner cavity of the mixing and diluting device, and the mixed gas inlet is communicated with the communication section; An adjusting rod is provided on the side wall of the mixing and diluting device. One end of the adjusting rod extends into the communication section and faces the mixed gas inlet. A tapered fit is formed between the end of the adjusting rod and the air outlet end of the mixed gas inlet. The inflow amount of the mixed gas in the mixed gas path is adjusted by the movement of the adjusting rod.

2. The aerosol dilution system according to claim 1, wherein An acceleration section is provided in the inner cavity of the mixing and diluting device. One end of the acceleration section is communicated with the first dilution gas inlet, and the other end is communicated with the communication section.

3. The aerosol dilution system according to claim 1, wherein The mixing chamber has a gradually expanding structure from the communication section to the air outlet direction.

4. The aerosol dilution system according to any one of claims 1 to 3, wherein The second dilution gas path and the aerosol gas path are connected to the mixed gas path through a tee structure, and a flow rate detection device is provided on the pipeline between the tee structure and the mixed gas inlet.

5. The aerosol dilution system according to any one of claims 1 to 3, wherein The first dilution gas path and the aerosol gas path are provided with clean gas by the same gas source system, and the second dilution gas path draws clean gas from the atmosphere through a dryer and a filter.

6. An aerosol dilution method, characterized in that, Applying the aerosol dilution system according to claim 4, the aerosol dilution method includes: Providing aerosol by the aerosol gas path, providing a first path of dilution gas by the first dilution gas path, and providing a second path of dilution gas by the second dilution gas path; Using the mixing and diluting device to perform jet mixing on the aerosol and the dilution gas; The aerosol and the second path of dilution gas are mixed in the tee structure and then flow into the inner cavity of the mixing and diluting device. The first path of dilution gas directly flows into the inner cavity of the mixing and diluting device. During the process of the first path of dilution gas flowing towards the air outlet of the mixing and diluting device, a negative pressure is generated, sucking the mixed gas of the aerosol and the second path of dilution gas into the inner cavity of the mixing and diluting device, so that the first path of dilution gas and the mixed gas are mixed in the inner cavity of the mixing and diluting device; The mixed gas then flows through the air outlet to the downstream buffer tank.

7. A photometer calibration device, characterized in that, Comprising: a gas source system, a calibration system, and an aerosol dilution system as described in any one of claims 1 to 5; the gas source system supplies clean gas to the first dilution gas path and the aerosol gas path; the calibration system includes a sampling chamber, the sampling chamber is connected with a photometer and a photometer to be calibrated, and the buffer tank is communicated with the sampling chamber through a pipeline.

8. The photometer calibration device according to claim 7, wherein the calibration system includes an upper fixture chamber and a lower fixture chamber, the upper fixture chamber and the lower fixture chamber move relative to each other to dock and enclose the sampling chamber, a weighing filter membrane fixture and a shunt ring are arranged between the upper fixture chamber and the lower fixture chamber, the photometer and the photometer to be calibrated are connected to the shunt ring through pipelines, and the air outlet end of the lower fixture chamber is connected with an air extraction pump.

9. The photometer calibration device according to claim 7, wherein the gas source system includes an air compressor, a steam drum, a cold dryer, a dryer, and a high-efficiency filter connected in sequence.

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