A compressed air microbiological sampler calibration device

Abstract

The utility model provides a kind of compressed air microbiological sampler calibration device, including compressed air gas transmission branch, microbiological aerosol input branch, pressure tank and pressure relief branch.Compressed air gas transmission branch can remove moisture, oil stain and miscellaneous bacteria in compressed air by three-stage filtration of water removal, oil removal and bacteria removal, to avoid impurity interference calibration results.Pressure detection device can monitor pressure in pressure tank in real time, to provide accurate pressure environment conditions for calibration under different pressure conditions of high, medium and low, to solve the problem of inaccurate cumulative volume caused by pressure difference of compressed air.Microbiological aerosol input branch generates standard aerosol containing microorganisms through monodisperse microbiological aerosol generator, and cooperates with second control valve to accurately control input timing and dose of aerosol.The utility model calibration device fills the blank of no calibration device for compressed air microbiological sampler calibration.

Description

Technical Field

[0001] This utility model relates to the field of equipment metrology, testing and calibration technology, specifically a calibration device for a compressed air microbial sampler. Background Technology

[0002] Compressed air is a commonly used production gas in biopharmaceuticals, vaccines, and other sterile products. Good Manufacturing Practices (GMP) for pharmaceuticals explicitly require that companies provide confirmation of the status of their air conditioning and purification systems, water systems, and compressed air equipment. Compressed air entering sterile areas must undergo sterile filtration and meet at least the microbial limit level for laminar air in Grade A areas (not exceeding 1 CFU / m³). Furthermore, ISO 14698-1:2003 clearly states that both compressed air and indoor air can generate biological contamination in high-risk areas. ISO 8573-7:2003 also provides methods for measuring the microbial content of compressed air. Microbial content is one of the key indicators of compressed air quality, and existing ISO international standards, national standards, and pharmaceutical manufacturing management practices all specify requirements or methods for testing the microbial content of compressed air. To ensure compliance with GMP regulations, most companies use compressed air microbial samplers to regularly test the microbial content of compressed air in sterile production areas.

[0003] A compressed air microbial sampler is a sampler specifically designed for collecting microorganisms from compressed air. Based on the Anderson or slit impaction principle, it generally employs two methods: pressure-holding sampling and pressure-relief sampling. Pressure-holding sampling involves maintaining pressure throughout the sampling process (the sampling pressure is consistent with the compressed air source). The instrument has built-in temperature, pressure, or flow sensors and integrates the sample volume to standard conditions (1 atmosphere, 20°C). The instrument automatically stops sampling when the sample volume reaches a preset value. Pressure-relief sampling decompresses the compressed gas to near-normal pressure before sampling. In practical applications, pressure-holding sampling is increasingly used for detecting microbial content in compressed air because the pressure-relief sampling device cannot be sterilized, and sudden pressure changes can lead to the death or damage of microorganisms, resulting in false negative results.

[0004] The current national standard JJF 1826-2020, "Calibration Specification for Air Microbial Samplers," primarily targets indoor atmospheric pressure air microbial samplers based on the Anderson impaction principle in cleanrooms / areas, focusing on key performance indicators such as sampling flow rate and sampling physical efficiency. However, compressed air microbial samplers calculate the cumulative sampling volume using the ideal gas law based on data from built-in pressure and flow sensors. The instrument's principle and operating method are fundamentally different from those of atmospheric pressure air microbial samplers. Therefore, the existing JJF 1826-2020 standard cannot be used for the calibration of compressed air microbial samplers. Consequently, a technical solution applicable to the calibration of compressed air microbial samplers is needed. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a calibration device for a compressed air microbial sampler.

[0006] To achieve the above objectives, the technical solution adopted by this utility model to solve its technical problem is: a compressed air microbial sampler calibration device, comprising a compressed air supply branch, a microbial aerosol input branch, a pressure tank, and a pressure relief branch. Both the compressed air supply branch and the microbial aerosol input branch are connected to the air inlet of the pressure tank. The compressed air supply branch includes a compressed air source, a water removal filter, an oil removal filter, a sterilization filter and a first control valve arranged sequentially along the air supply direction. The microbial aerosol input branch includes a monodisperse microbial aerosol generator and a second control valve. The pressure tank is equipped with a pressure detection device for detecting the pressure inside its cavity. The bottom of the pressure tank is provided with a drain outlet, and a third control valve is installed at the drain outlet; The pressure tank is provided with a first detection outlet and a second detection outlet that communicate with the inner cavity. A fourth control valve is installed at the first detection outlet and a fifth control valve is installed at the second detection outlet. The pressure relief branch is connected to the exhaust port of the pressure tank. The pressure relief branch includes a sixth control valve, a filter, a seventh control valve and an exhaust pump arranged sequentially along the exhaust direction. A pressure relief valve is also connected to the pipeline between the filter and the seventh control valve via a three-way connector.

[0007] This invention's compressed air delivery branch employs a three-stage filtration system—water removal, oil removal, and sterilization—to remove moisture, oil, and bacteria from compressed air, preventing impurities from interfering with calibration results. The pressure detection device monitors the pressure tank in real time, providing precise pressure environmental conditions for calibration under high, medium, and low pressure conditions, thus solving the problem of inaccurate cumulative volume due to pressure differences in compressed air. The microbial aerosol input branch generates standard aerosols containing microorganisms through a monodisperse microbial aerosol generator, and, in conjunction with a second control valve, precisely controls the timing and dosage of aerosol input. This invention's calibration device fills the current gap in the lack of calibration devices for compressed air microbial samplers.

[0008] When calibrating the sampling physical efficiency of the compressed air microbial sampler under test, the outlet of the fourth control valve is connected to the membrane filtration sampler via a pipeline, and the outlet of the fifth control valve is connected to the compressed air microbial sampler under test via a pipeline. The pressure tank is first depressurized before the monodisperse microbial aerosol generator is turned on to allow standard aerosols containing standard strains to smoothly enter the pressure tank. After the standard aerosol input is complete, compressed air is then pressurized into the pressure tank to ensure microbial activity and improve the accuracy of the sampling physical efficiency test of the compressed air microbial sampler. The membrane filtration sampler (as a standard comparison device) samples simultaneously with the compressed air microbial sampler under test, and the sampling physical efficiency of the sampler under test can be calculated by comparing colony counts.

[0009] When calibrating the flow rate of the compressed air microbial sampler under test, the outlet of the fourth or fifth control valve is connected in series with a standard flow meter and the sampler under test via a pipeline. This allows for direct comparison of the standard flow rate data with the flow rate display value of the sampler under test, thus calibrating the error in the sampled flow rate indication.

[0010] Furthermore, it also includes a particle size spectrometer with a maximum permissible error of ±20%; a first detection port for installing the particle size spectrometer probe is provided on the pipeline between the first detection outlet of the pressure tank and the fourth control valve, and a second detection port for installing the particle size spectrometer probe is provided on the pipeline between the second detection outlet of the pressure tank and the fifth control valve.

[0011] By adopting the above-mentioned preferred scheme, particle size spectrometer probes are installed at the first and second probe ports via pressure reducing valves. This allows for real-time monitoring of the aerosol particle size distribution and concentration output from the pressure tank to the two sampling branches. It can accurately determine whether the aerosols in the tank are uniformly mixed, ensuring the consistency of samples for subsequent physical efficiency calibration and avoiding calibration errors caused by uneven aerosol distribution, thereby further improving the accuracy of the physical efficiency calibration results.

[0012] Furthermore, a third detection port for installing a particle size analyzer probe is provided at the connection between the microbial aerosol input branch and the pressure tank.

[0013] Using the preferred scheme described above, a particle size distribution of aerosols can be monitored in real time by installing a particle size spectrometer probe at the third detection port via a pressure reducing valve.

[0014] Furthermore, the first detection outlet and the second detection outlet of the pressure tank are located at the same height position of the pressure tank.

[0015] Furthermore, it also includes a stirring mechanism, which includes a stirring shaft and a stirring drive motor. The stirring shaft is rotatably mounted on the wall of the pressure tank and extends inward. The end of the stirring shaft is provided with stirring blades. The stirring drive motor is mounted on the outside of the pressure tank and can drive the stirring shaft to rotate.

[0016] By adopting the above-mentioned preferred scheme, the stirring mechanism drives the stirring blades to rotate through the stirring drive motor, which can accelerate the mixing speed of compressed air and microbial aerosol in the pressure tank, shorten the mixing time, and improve the calibration efficiency.

[0017] Furthermore, the standard flow meter is a mass flow meter with volume correction and integration functions, and its accuracy class is not lower than Class 2.

[0018] Using the above-mentioned preferred scheme, a mass flow meter with an accuracy class of not less than 2 can ensure the accuracy of flow measurement and meet the calibration accuracy requirements of compressed air samplers. The volume correction function can convert the measured actual volume into the volume under standard conditions (1 standard atmosphere, 20℃) based on the real-time pressure and temperature data inside the pressure tank. The integration function can automatically accumulate the total flow during the sampling process without manual calculation, simplifying the operation process, reducing manual recording errors, and improving the efficiency and data accuracy of sampling volume calibration.

[0019] Furthermore, the monodisperse microbial aerosol generator can produce monodisperse particles with a particle size of 0.7μm-15μm.

[0020] Using the preferred scheme described above, the particle size range of 0.7μm-15μm covers the typical particle size range of common microorganisms in compressed air, which can simulate the particle size distribution of microorganisms in compressed air in actual applications, making the calibration scenario closer to the real use environment.

[0021] Furthermore, the maximum permissible error of the flow rate of the membrane filtration sampler is ±5%.

[0022] Using the above-mentioned preferred scheme, the membrane filtration sampler with a maximum permissible flow rate error of ±5% is used as the standard device. Its own flow rate accuracy can meet the calibration requirements, ensuring the accuracy of the calculated sampling physical efficiency data.

[0023] Furthermore, it also includes a microbial incubator for microbial cultivation, with an adjustable temperature range of 5℃-100℃ and a temperature deviation of no more than ±1℃.

[0024] Using the above-mentioned preferred scheme, the incubator with an adjustable temperature range of 5℃-100℃ can meet the cultivation needs of common standard strains such as Bacillus subtilis and is suitable for different microbial calibration scenarios; the high-precision temperature control capability with a temperature deviation of no more than ±1℃ can ensure the stability of the culture environment temperature, avoid abnormal colony growth due to temperature fluctuations, and ensure the accuracy of subsequent colony counting. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a structural schematic diagram of one embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the connection structure for flow calibration of the compressed air microbial sampler under test.

[0028] Figure 3 This is a schematic diagram of the connection structure for calibrating the sampling physical efficiency of the compressed air microbial sampler under test.

[0029] The numbers and letters in the diagram represent the names of the corresponding components: 11-Water removal filter; 12-Oil removal filter; 13-Bacterial removal filter; 14-First control valve; 21-Monodispersive microbial aerosol generator; 22-Second control valve; 31-Pressure tank; 32-Pressure detection device; 33-Stirring mechanism; 41-Third control valve; 42-Standard flow meter; 511-Fourth control valve; 512-Membrane filtration sampler; 513-Particle size spectrometer probe; 521-Fifth control valve; 522-Particle size spectrometer probe; 61-Sixth control valve; 62-Filter; 63-Seventh control valve; 64-Exhaust pump; 65-Pressure relief valve; 70-Microbial sampler of compressed air under test. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] like Figure 1As shown, a compressed air microbial sampler calibration device includes: This includes a compressed air supply branch, a microbial aerosol input branch, a pressure tank 31, and a pressure relief branch. Both the compressed air supply branch and the microbial aerosol input branch are connected to the air inlet of the pressure tank 31. The compressed air supply branch includes a compressed air source, a water removal filter 11, an oil removal filter 12, a sterilization filter 13 and a first control valve 14 arranged sequentially along the air supply direction. The microbial aerosol input branch includes a monodisperse microbial aerosol generator 21 and a second control valve 22. The pressure tank 31 is equipped with a pressure detection device 32 for detecting the pressure inside its cavity; The bottom of the pressure tank 31 is provided with a drain outlet, and a third control valve 41 is installed at the drain outlet; The pressure tank 31 is provided with a first detection outlet and a second detection outlet that communicate with the inner cavity. A fourth control valve 511 is installed at the first detection outlet, and a fifth control valve 512 is installed at the second detection outlet. The pressure relief branch is connected to the exhaust port of the pressure tank 31. The pressure relief branch includes a sixth control valve 61, a filter 62, a seventh control valve 63 and an exhaust pump 64 arranged sequentially along the exhaust direction. A pressure relief valve 65 is also connected to the pipeline between the filter 62 and the seventh control valve 63 via a three-way connector.

[0032] The compressed air supply branch uses a three-stage filtration system for water removal, oil removal, and sterilization to remove moisture, oil, and bacteria from the compressed air, preventing impurities from interfering with calibration results. The pressure detection device monitors the pressure inside the pressure tank in real time, providing precise pressure environmental conditions for calibration under high, medium, and low pressure conditions, solving the problem of inaccurate cumulative volume due to pressure differences in compressed air. The microbial aerosol input branch generates standard aerosols containing microorganisms through a monodisperse microbial aerosol generator, and, in conjunction with a second control valve, precisely controls the timing and dosage of aerosol input. This novel calibration device fills the gap in current calibration methods for compressed air microbial samplers, addressing the lack of such a device.

[0033] like Figure 2 As shown, during flow calibration of the compressed air microbial sampler under test, the outlet of the fourth control valve 511 is connected in series with the standard flow meter 42 and the compressed air microbial sampler 70 under test via a pipeline. The standard flow data can be directly compared with the flow display value of the sampler under test, thus calibrating the error in the sampled flow indication.

[0034] like Figure 3As shown, during the calibration of the sampling physical efficiency of the compressed air microbial sampler under test, the outlet of the fourth control valve 511 is connected to the membrane filtration sampler 512 via a pipeline, and the outlet of the fifth control valve 521 is connected to the compressed air microbial sampler 70 under test via a pipeline. During calibration, the pressure tank is first depressurized before the monodisperse microbial aerosol generator is turned on to ensure that the standard aerosol containing the standard strain enters the pressure tank smoothly. After the standard aerosol input is completed, the compressed air input into the pressure tank is pressurized to ensure microbial activity and improve the accuracy of the sampling physical efficiency test of the compressed air microbial sampler. The membrane filtration sampler (as a standard comparison device) samples synchronously with the compressed air microbial sampler under test, and the sampling physical efficiency of the sampler under test can be calculated by comparing the colony counts.

[0035] In some other embodiments of this utility model, a particle size spectrometer is also included, with a maximum permissible error of ±20%. The first and second detection outlets of the pressure tank 31 are located at the same height within the pressure tank. A first detection port for installing the particle size spectrometer probe 513 is provided on the pipeline between the fourth control valve 511 and the pressure tank 31, and a second detection port for installing the particle size spectrometer probe 522 is provided on the pipeline between the fifth control valve 521 and the pressure tank 31. The beneficial effects of adopting the above technical solution are: by installing the particle size spectrometer probes through the pressure reducing valves at the first and second detection ports, the aerosol particle size distribution and concentration output from the pressure tank to the two sampling branches can be monitored in real time. This allows for accurate determination of whether the aerosols in the tank are uniformly mixed, ensuring the consistency of samples for subsequent physical efficiency calibration and avoiding calibration errors caused by uneven aerosol distribution, thereby further improving the accuracy of the physical efficiency calibration results.

[0036] In some other embodiments of this utility model, a stirring mechanism 33 is also included. The stirring mechanism 33 includes a stirring shaft and a stirring drive motor. The stirring shaft is rotatably mounted on the wall of the pressure tank and extends inward. Stirring blades are provided at the end of the stirring shaft. The stirring drive motor is mounted on the outside of the pressure tank and can drive the stirring shaft to rotate. The beneficial effects of adopting the above technical solution are: the stirring mechanism, by driving the stirring blades to rotate via the stirring drive motor, can accelerate the mixing speed of compressed air and microbial aerosols within the pressure tank, shorten the mixing time, and improve calibration efficiency.

[0037] In some other embodiments of this utility model, the standard flow meter 42 is a mass flow meter with volume correction and integration functions, and its accuracy class is not lower than 2. The beneficial effects of adopting the above technical solution are: the mass flow meter with an accuracy class of not lower than 2 can ensure the accuracy of flow measurement and meet the calibration accuracy requirements of compressed air samplers; the volume correction function can convert the measured actual volume into the volume under standard conditions (1 standard atmosphere, 20°C) based on the real-time pressure and temperature data in the pressure tank; the integration function can automatically accumulate the total flow during the sampling process without manual calculation, simplifying the operation process, reducing manual recording errors, and improving the efficiency and data accuracy of sampling volume calibration.

[0038] In some other embodiments of this invention, the monodisperse microbial aerosol generator 21 can produce monodisperse particles with a diameter of 0.7 μm to 15 μm. The beneficial effect of adopting the above technical solution is that the particle size range of 0.7 μm to 15 μm covers the typical particle size range of common microorganisms in compressed air, which can simulate the particle size distribution of microorganisms in compressed air in actual applications, making the calibration scenario closer to the real-world usage environment.

[0039] In some other embodiments of this utility model, the maximum permissible error of the flow rate of the membrane filtration sampler 512 is ±5%. The beneficial effect of adopting the above technical solution is that the membrane filtration sampler with a maximum permissible error of ±5% can serve as a standard device, and its own flow rate accuracy can meet the calibration requirements, ensuring the accuracy of the calculated sampling physical efficiency data.

[0040] In some other embodiments of this utility model, a microbial incubator for microbial culture is also included, with an adjustable temperature range of 5℃-100℃ and a temperature deviation of no more than ±1℃. The beneficial effects of adopting the above technical solution are: the incubator with an adjustable temperature range of 5℃-100℃ can meet the culture requirements of common standard strains such as Bacillus subtilis, and is adaptable to different microbial calibration scenarios; the high-precision temperature control capability with a temperature deviation of no more than ±1℃ ensures a stable culture environment temperature, avoids abnormal colony growth due to temperature fluctuations, and ensures the accuracy of subsequent colony counting.

[0041] The calibration process is described below with reference to one embodiment of the present invention.

[0042] like Figure 2As shown, when calibrating the flow indication error of the tested compressed air microbial sampler, the tested compressed air microbial sampler 70 and the standard flow meter 42 are connected to the outlet of the fourth control valve via pipelines. The tested compressed air microbial sampler 70 is preheated according to the instruction manual, the protective cover is removed, and the matching petri dish is placed. First, the second control valve 22, the third control valve 41, the fourth control valve 511, the fifth control valve 521, and the sixth control valve 61 are closed, and the first control valve 14 is opened. The compressed air source is started to replenish the pressure tank 31 with air. The pressure in the pressure tank is monitored in real time by the pressure detection device 32. After the pressure stabilizes at 0.2 MPa, the air replenishment is stopped, the fourth control valve 511 is opened, and after running according to the set program, the flow of the tested compressed air microbial sampler is measured with the standard flow meter 42, and the flow indication error is calculated by comparison. After measuring the flow indication error under a pressure of 0.2 MPa, continue to replenish air into the pressure tank and follow the above steps to measure the flow indication error of the tested compressed air microbial sampler under pressures of 0.4 MPa and 0.4 MPa respectively.

[0043] like Figure 3As shown, when calibrating the sampling physical efficiency of the compressed air microbial sampler under test, the membrane filtration sampler 512 is connected to the outlet of the fourth control valve 511 via a pipeline, and the compressed air microbial sampler 70 under test is connected to the outlet of the fifth control valve 521 via a pipeline. The compressed air microbial sampler 70 under test is preheated according to the instruction manual, the protective cover is removed, and the matching petri dish is placed. First, close the first control valve 14, the second control valve 22, the third control valve 41, the fourth control valve 511, and the fifth control valve 521, and open the sixth control valve 61. The pressure in the pressure tank is then released to normal pressure through the pressure relief valve 65, or the seventh control valve 63 is opened and the exhaust pump 64 is turned on to draw the pressure inside the pressure tank 31 to a slight negative pressure. A suspension of a certain concentration of bacterial standard material is placed in a monodisperse microbial aerosol generator. The second control valve 22 is opened, and the selected particle size is calibrated according to the sampling physical efficiency. By controlling the liquid inlet flow rate and the vibration frequency of the generator, monodisperse particles with a particle size between 0.7μm and 15μm are generated. The standard aerosol containing the bacterial strain is input into the pressure tank 31. After completion, the second control valve 22 is closed, the first control valve 14 is opened, and the compressed air source is started to replenish the pressure tank 31. The stirring mechanism 33 is turned on, and the pressure inside the pressure tank is monitored in real time by the pressure detection device 32. After the internal pressure stabilizes at the set pressure, the replenishment is stopped and the first control valve 14 is closed. The particle concentration at the first and second detection outlets is measured by a particle size analyzer. When the particle concentrations at the two outlets are consistent, the fourth control valve 511 and the fifth control valve 521 are opened simultaneously. After the membrane filtration sampler and the tested compressed air microbial sampler each collect a set volume of gas, the fourth control valve 511 and the fifth control valve 521 are closed. Remove the filter membrane from the membrane filtration sampler and place it on tryptophan-soybean nutrient agar medium. Integrate this agar with the tryptophan-soybean nutrient agar medium collected by the compressed air microbial sampler under test, and incubate for at least 18 hours. Count visible colonies using the naked eye or an automated colony counter. Divide the colony count measured by the compressed air microbial sampler under test by the sum of the colony counts measured by the membrane filtration sampler, and multiply by 100% to obtain the sampling physical efficiency of the compressed air microbial sampler for this particle size.

[0044] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A calibration device for a compressed air microbial sampler, characterized in that, This includes compressed air delivery branches, microbial aerosol input branches, pressure tanks, and pressure relief branches. Both the compressed air supply branch and the microbial aerosol input branch are connected to the air inlet of the pressure tank. The compressed air supply branch includes a compressed air source, a water removal filter, an oil removal filter, a sterilization filter and a first control valve arranged sequentially along the air supply direction. The microbial aerosol input branch includes a monodisperse microbial aerosol generator and a second control valve. The pressure tank is equipped with a pressure detection device for detecting the pressure inside its cavity. The bottom of the pressure tank is provided with a drain outlet, and a third control valve is installed at the drain outlet; The pressure tank is provided with a first detection outlet and a second detection outlet that communicate with the inner cavity. A fourth control valve is installed at the first detection outlet and a fifth control valve is installed at the second detection outlet. The pressure relief branch is connected to the exhaust port of the pressure tank. The pressure relief branch includes a sixth control valve, a filter, a seventh control valve and an exhaust pump arranged sequentially along the exhaust direction. A pressure relief valve is also connected to the pipeline between the filter and the seventh control valve via a three-way connector.

2. The compressed air microbial sampler calibration device according to claim 1, characterized in that, When calibrating the sampling physical efficiency of the compressed air microbial sampler under test, the outlet of the fourth control valve is connected to the membrane filter sampler via a pipeline, and the outlet of the fifth control valve is connected to the compressed air microbial sampler under test via a pipeline.

3. The compressed air microbial sampler calibration device according to claim 2, characterized in that, It also includes a particle size spectrometer with a maximum permissible error of ±20%; a first detection port for installing the particle size spectrometer probe is provided on the pipeline between the first detection outlet of the pressure tank and the fourth control valve, and a second detection port for installing the particle size spectrometer probe is provided on the pipeline between the second detection outlet of the pressure tank and the fifth control valve.

4. The compressed air microbial sampler calibration device according to claim 3, characterized in that, A third detection port for installing a particle size analyzer probe is provided at the connection between the microbial aerosol input branch and the pressure tank.

5. The compressed air microbial sampler calibration device according to claim 2, characterized in that, The first and second detection outlets of the pressure tank are located at the same height on the pressure tank.

6. The compressed air microbial sampler calibration device according to claim 1, characterized in that, When calibrating the flow rate of the compressed air microbial sampler under test, the outlet of the fourth or fifth control valve is connected in series with the flow meter and the compressed air microbial sampler under test via a pipeline.

7. The compressed air microbial sampler calibration device according to claim 1, characterized in that, It also includes a stirring mechanism, which includes a stirring shaft and a stirring drive motor. The stirring shaft is rotatably mounted on the wall of the pressure tank and extends inward. The end of the stirring shaft is provided with stirring blades. The stirring drive motor is mounted on the outside of the pressure tank and can drive the stirring shaft to rotate.

8. The compressed air microbial sampler calibration device according to claim 6, characterized in that, The flow meter is a mass flow meter with volume correction and integration functions, and its accuracy class is not lower than Class 2.

9. The compressed air microbial sampler calibration device according to claim 1, characterized in that, The monodisperse microbial aerosol generator can produce monodisperse particles with a diameter of 0.7μm-15μm.

10. The compressed air microbial sampler calibration device according to claim 2, characterized in that, The maximum permissible error for the flow rate of the membrane filtration sampler is ±5%.

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