Microbial pathogen aerosol sampling device and pathogen concentration calculation method

Abstract

The invention belongs to the technical field of aerosol sampling, and discloses a microbial pathogen aerosol sampling device and a pathogen concentration calculation method. The device comprises a fan, a sampler, a sampling pipe, a sampler shell, a touch screen, a silica gel sealing ring, a lithium battery pack, a charging head, a main control circuit board, a base, a gas flowmeter, a pressure sensor, a temperature sensor, a filter and a hose, and the volume of sampled gas is converted into the volume of gas under the standard atmospheric pressure of 25 DEG C through the pressure sensor and the temperature sensor; the concentration of the pathogen in the aerosol is calculated by combining the volume of a sample and the qPCR technology, meanwhile, a battery is adopted for power supply, the device is convenient to carry, has the characteristics of high sampling speed, high collection efficiency, small volume of a collected product and the like, and is suitable for sampling the microbial pathogen aerosol in a multi-scene open environment. The method has important value and significance in environmental health and biological safety.

Description

Technical Field

[0001] The invention relates to the technical field of aerosol sampling, and in particular to a microbial pathogen aerosol sampling device and a method for calculating pathogen concentration. Background Art

[0002] The outbreak and prevalence of infectious diseases with aerosols as the transmission medium is one of the main reasons that pose a serious threat to human health and environmental safety. Therefore, regular sampling and detection of aerosols in the environment is necessary, but the current aerosol sampling devices generally have problems such as low sampling efficiency, complex structure and insufficient portability. For example, Patent No. CN 212640487 U discloses a wet wall cyclone microbial aerosol sampler, which has a simple structure but no built-in power supply and still requires an external power supply, which has certain limitations when used; Patent No. CN 214471934 U discloses a bioaerosol automatic sampling device, which integrates liquid replenishment, liquid discharge and sampling, and has good automation, but the complex structural design leads to its insufficient portability; Patent No. CN 214471933 U discloses a portable large-flow bioaerosol enrichment and liquid phase sampling device, which has a simple structure and a built-in battery, and has good portability, but the device has a poor airtightness at the connection between the turbine fan and the sampling tube, which easily leads to a reduction in sampling efficiency. At the same time, the above-mentioned equipment cannot accurately measure the sampling gas flow rate and control the sampled gas volume, especially the sampling of standard air volumes at different pressures and temperatures. Therefore, it is urgent to design a portable aerosol sampling device to realize the calculation of the sampling gas flow rate, sampling gas volume and sampling aerosol pathogen concentration. This has important application value and significance for promoting the development of aerosol sampling technology and ensuring environmental hygiene and biosafety. Summary of the invention

[0003] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a microbial pathogen aerosol sampling device and a method for calculating the pathogen concentration. The sampled air volume is converted into the air volume under standard atmospheric pressure at 25°C by a gas flow meter, a pressure sensor and a temperature sensor, so as to achieve precise control of the sampled air volume, and combine the qPCR technology to realize the calculation of the pathogen concentration in the aerosol, so as to solve the problems faced by the existing aerosol samplers, such as the inability to achieve precise control of the sampling flow rate and sampling volume, and the inability to calculate the concentration of microbial pathogens in the sampled samples, and solve the problems of the complex structure and insufficient portability of the aerosol sampler.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a microbial pathogen aerosol sampling device, comprising a fan, a sampler, a sampling tube, a sampler housing, a touch screen, a silicone seal, a lithium battery pack, a charging head, a main control circuit board, a base, a gas flow meter, a pressure sensor, a temperature sensor, a filter and a hose;

[0006] The sampler housing is connected to the base, and the sampler housing is used to fix the fan, gas flow meter, pressure sensor, temperature sensor, sampler, touch screen, lithium battery and charging head;

[0007] The top of the sampler is provided with an air outlet, the upper side of the sampler is provided with at least two tangential air inlets, the bottom of the sampler is provided with a sampling port, the sampling port is connected to the sampling tube, and the air outlet is connected to the hose;

[0008] The gas flow meter, pressure sensor, temperature sensor and filter are arranged on the hose;

[0009] The lithium battery pack is connected to the charging head, the signal output ends of the gas flow meter, pressure sensor, and temperature sensor are connected to the signal input end of the main control circuit board, the signal output end of the main control circuit board is connected to the signal input end of the fan, the main control circuit board is connected to the touch screen signal, and the lithium battery pack is electrically connected to the main control circuit board;

[0010] The silicone sealing ring is fixed on the top of the connection between the sampler housing and the sampler.

[0011] Furthermore, filters are installed at the at least two tangential air inlets.

[0012] Furthermore, the connection between the sampler housing and the sampler is in a circular ring shape, and the inner ring is provided with an external thread for forming a threaded fit with the sampler. A fan fixing hole and a wire hole are provided on the top of the sampler housing. The diameter of the fan fixing hole is the same as the diameter of the fan and is used to fix the fan. The wire hole is used to lead the fan wire to the interior of the sampler housing. A plurality of bosses are provided on the inner side of the bottom of the sampler housing, and each boss is provided with a boss circular hole. The boss circular hole is concentric with the circular hole provided on the base and is used to connect the base.

[0013] Furthermore, it also includes a foam pad, which is arranged at the lower end of the base.

[0014] Furthermore, the diameter of the sampler is determined according to the cutting particle size; wherein the cutting particle size is the microbial aerosol particle size located on the cylindrical surface CS, and the cylindrical surface CS is a cylindrical surface existing inside the sampler and extending downward from the exhaust direction to the bottom of the sampler, and the aerosol particles on the cylindrical surface CS are balanced.

[0015] Furthermore, the cutting particle size is determined by the following method:

[0016] The tangential velocity and axial velocity on the cylindrical surface CS are determined according to the force on the microbial aerosol in the sampler; wherein the force on the microbial aerosol in the sampler includes the outward centrifugal force and the inward airflow resistance, which are respectively expressed as:

[0017]

[0018] F stokes =3πχμv rCS

[0019] In the formula, CF is the centrifugal force, x is the aerosol particle size, R X is the sampler radius, χ is the air viscosity, ρ p is the aerosol density, v θCS is the tangential velocity on the cylindrical surface CS, v rCS is the axial velocity on the cylindrical surface CS, F stokes is the inward airflow resistance, μ is the air viscosity;

[0020] Based on the tangential velocity and axial velocity on the cylindrical surface CS, the cutting particle size is calculated by the following formula:

[0021]

[0022] In the formula, x 50 is the cutting particle size, D x is the sampler diameter.

[0023] Further, the main control circuit board is configured to calculate the current cumulative sampled gas volume V based on the following formula:

[0024]

[0025] Where Q is the sampling air flow rate, dt is the sampling time, P is the pressure at the time of sampling, and T is the temperature value at the time of sampling.

[0026] Further, the main control circuit board is configured to calculate the concentration ρ of microbial pathogens in the aerosol based on the following formula:

[0027] ρ=f(C t )×V1 / Vη

[0028] In the formula, f(C t ) is the initial copy number obtained by searching the standard curve of fluorescence quantitative PCR, V1 is the sample volume, V is the corrected sampling gas volume at 25°C and one atmosphere, and η is the aerosol sampling efficiency.

[0029] In a second aspect, the present invention provides a method for calculating pathogen concentration, based on the microbial pathogen aerosol sampling device as described above, the method comprising:

[0030] Add sampling liquid into the sampling tube;

[0031] Set the working time and sampling rate or sampling gas volume of the microbial pathogen aerosol sampling device;

[0032] The fan is controlled to start running, and the external air enters the sampler from the air inlet. The external air will form a cyclone vortex after entering the sampler, and make a spiral rotation from top to bottom along the inner wall of the sampler. During this process, the aerosol particles in the air will be affected by centrifugal force and gravity and move toward the sampling port. When the vortex reaches the bottom of the sampler, the air will rotate upward along the axis of the sampler and be drawn out of the sampler from the air outlet by the fan;

[0033] According to the signal from the gas flow meter, the current flowing through the fan is adjusted to maintain the set sampling efficiency;

[0034] The current gas flow signal is obtained in real time through the main control circuit board, the current sampled gas volume value is accumulated and calculated, and displayed in real time on the touch screen;

[0035] When the environmental pathogenic microorganism aerosol sampling device works for the set time or sampling gas volume, the sample is taken out from the sampling tube for qPCR testing;

[0036] After the qPCR reaction is completed, in response to the input Ct value, the main control circuit board calculates the concentration value of the microbial pathogen based on the sampled gas volume value, Ct value, and the sampling efficiency of the equipment; among them, the Ct value is automatically displayed after the qPCR reaction is completed, which means the number of amplification cycles corresponding to when the fluorescence signal of the amplified product reaches the set fluorescence threshold.

[0037] Furthermore, when the environmental pathogenic microorganism aerosol sampling device works for a set time or samples a gas volume, the method further includes:

[0038] The touch screen displays the information about the completion of the operation, the volume of the sampled gas, and the Ct value after the test is completed. Remove the sampler and sampling tube.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention improves the airtightness of environmental pathogenic microorganism aerosols during the sampling process by setting the connection between the sampler housing and the sampler into a cylindrical ring shape and using threaded fitting to connect and fix the sampler housing to the sampler. At the same time, a silicone sealing ring is added at the connection between the sampler and the sampler housing to prevent air overflow.

[0041] 2. The present invention is provided with four tangential air inlets, which optimizes the appearance design of the aerosol sampler and improves the sampling efficiency of the aerosol sampling device.

[0042] 3. The present invention is internally provided with a battery and a capacitive LCD touch screen, which improves the interactivity of the aerosol sampling device.

[0043] 4. The present invention is internally provided with a control circuit to control the rotation speed of the fan, thereby achieving control of the sampling flow rate, so that the aerosol sampling device has better adaptability.

[0044] 5. The present invention is internally provided with an LCD touch screen, which can realize free setting of the sampling time (1-99 minutes) or the sampling gas volume (1-99m3) to meet different sampling requirements.

[0045] 6. The present invention establishes a method for calculating the volume of sampled gas, and utilizes a gas flow meter, a pressure sensor, and a temperature sensor to achieve accurate cumulative calculation of the volume of sampled gas, which is used for accurate control of the volume of sampled gas and calculation of pathogen concentration in aerosols.

[0046] 7. The present invention establishes a method for calculating the concentration of pathogens in aerosols, and uses the Ct value of the qPCR reaction to calculate the concentration of pathogens in aerosols by searching the fluorescence quantitative PCR standard curve.

[0047] 8. The patent of this invention establishes a sampling gas flow rate control method using a gas flow meter, which can maintain high sampling efficiency under different working conditions and derive the concentration of pathogens in the aerosol. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0049] Figure 1 The figure is an overall structural diagram of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0050] Figure 2 It is a rear bottom view of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0051] Figure 3 It is a side view of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0052] Figure 4This is a connection diagram of a gas flow meter, a pressure sensor, a temperature sensor and a hose of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0053] Figure 5 The present invention is a structural diagram of a sampler housing of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0054] Figure 6 The sampler structure diagram of a microbial pathogen aerosol sampling device according to an embodiment of the present invention.

[0055] Figure 7 4 is a flow chart of aerosol sampling flow correction control according to an embodiment of the present invention.

[0056] Figure 8 Flow chart of a method for calculating pathogen concentration according to an embodiment of the present invention.

[0057] Figure markings: 1-sampler housing; 2-sampler; 3-sampling tube; 4-capacitive LCD touch screen; 5-button switch; 6-blower; 7-charging head; 8-foam pad; 9-base; 10-silicone sealing ring; 11-gas flow meter; 12-battery pack; 13-main control circuit board and the pressure sensor and temperature sensor integrated thereon; 14-filter; 15-hose; 101-wire hole; 102-inner ring; 103-ring hole; 104-ring boss; 105-boss; 201-air outlet channel; 202-air inlet; 203-sampling port. DETAILED DESCRIPTION

[0058] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0059] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] The present invention will now be further described with reference to the accompanying drawings.

[0062] The embodiment of the present invention provides a microbial pathogen aerosol sampling device, such as Figures 1 to 6 As shown, the device includes: a sampler housing 1, a sampler 2, a sampling tube 3, an LCD capacitive touch screen 4, a button switch 5, a fan 6, a charging head 7, a foam pad 8, a base 9, a silicone sealing ring 10, a pressure sensor, a gas flow meter 11, a battery pack 12, a main control circuit board and a pressure sensor and a temperature sensor integrated thereon 13, a filter 14, and a hose 15.

[0063] A cylindrical air outlet channel 201 is provided on the top of the sampler 2 for discharging the internal air. Four rectangular tangential air inlets 202 are provided on the upper side for allowing the air to enter the sampler 2 in the form of a cyclone. A sampling port 203 is provided at the bottom for connecting the sampling tube 3, which contains an aerosol sampling liquid.

[0064] The sampler housing 1 is used to fix the fan 6, the sampler 2, the capacitive screen 4, the button switch 5, the charging head 7, the gas flow meter 11 and the connecting base 9.

[0065] The base 9 is used to fix the lithium battery pack 12 and the main control circuit board and the pressure sensor, gas flow meter and temperature sensor 13 integrated thereon. The main control circuit board is also connected to the LCD capacitive touch screen 4 and the fan 6 to control the working parameters of the fan 6 and the display information of the LCD capacitive touch screen 4. The button switch 5 is connected to the battery pack 12 and is a power switch. The battery pack 12 is connected to the charging head 7 to be charged through the charging head 7. The battery pack 12 is connected to the main control circuit board to power the main control circuit board and power other electronic components through the main control circuit board. Among them, other electronic components include the fan 6, the gas flow meter 11, the pressure sensor and the temperature sensor 13 and the LCD capacitive touch screen 4.

[0066] The silicone sealing ring 10 is fixed on the top of the connection between the sampler housing 1 and the sampler 2 to improve the airtightness of the sampling device.

[0067] Among them, an internal thread is provided inside the cylindrical air outlet channel 201 on the top of the sampler 2, and the length of the internal thread is less than the total length of the air outlet channel 201, which is used to form a threaded fit with the sampler housing 1, and an internal thread is provided inside the bottom sampling port 203, which is used to form a threaded fit with the sampling tube 3.

[0068] Among them, the connection between the sampler housing 1 and the sampler 2 is a cylindrical ring, and the inner ring 102 is provided with an external thread for forming a threaded fit with the sampler 2. Four bosses 105 are provided on the inner side of the bottom of the sampler housing 1, and each boss 105 is provided with a circular hole. The circular hole of the boss is concentric with the circular hole of the base and is used to connect the base 9. A circular boss 104 is provided on the inner wall of the bottom of the sampler housing 1, which is connected to the hose 15 and is used to fix the wind turbine 6 to form a closed air path. A circular hole 101 is provided on the outer side of the bottom of the sampler housing 1 for passing the wind turbine 6. A circular hole 103 is provided in the sampling housing 1, which is connected to the gas flow meter 11 to allow the air flow to flow through the inside of the gas flow meter 11.

[0069] The base 9 is provided with four grooves for fixing the foam pad 8 .

[0070] Among them, the filter 14 and the gas flow meter 11 are fixed by threaded cooperation, the hose 15 is clamped on the filter 14 and the annular boss 104, and glue is added to both sides to improve the air tightness, the fan 6 is clamped on the annular boss 104, and glue is added to strengthen the fixation, the button switch 5 is fixed to the front side of the sampler housing 1 by a nut, the charging head 7 is fixed to the back side of the sampler housing 1 by a nut, the capacitive LCD touch screen 4 is fixed to the inner side of the sampler housing 1 by self-tapping screws, the base 9 is fixed to the fixed boss 105 by screws, the silicone sealing ring 10 is clamped on the top of the connection between the sampler housing 1 and the sampler 2, the lithium battery pack 12 and the main control circuit board and the pressure sensor and temperature sensor 13 integrated thereon are fixed to the base 9 by screws, and the foam pad 8 is fixed to the groove of the base 9 by double-sided tape.

[0071] In this embodiment, the sampler 2 is selected as an aerosol sampler. The sampling tube diameter design of the aerosol sampler has an important influence on the sampling efficiency. The forces on the microbial aerosol in the aerosol sampler are the outward centrifugal force and the inward airflow resistance, where the centrifugal force is:

[0072]

[0073] The inward airflow resistance is:

[0074] F stokes =3πχμv rCS

[0075] There is a cylindrical surface CS inside the cyclone sampler that extends from the exhaust pipe downward to the bottom of the cyclone sampler. The aerosol particles are balanced on this surface. The particle size of the microbial aerosol on this surface is the cut-off particle size. Through the balance equation, the cut-off particle size x can be obtained. 50 The calculation formula is as follows:

[0076]

[0077] Where x is the aerosol particle size, R X is the radius of the sampler, χ is the air viscosity, μ is the air viscosity, ρ P is the aerosol density, v θCS is the tangential velocity on the CS surface, v rCS is the axial velocity on the CS surface, D x is the diameter of the exhaust pipe. is the diameter of the exhaust pipe. The latter two can be calculated through the sampler inlet velocity and geometric parameters.

[0078] In order to reduce the cutting particle size x 50 Due to air viscosity, the aerosol density cannot be changed. Therefore, it is necessary to increase the tangential velocity and reduce the axial velocity and outlet diameter. Figure 6 The cyclone aerosol design shown ultimately designs the sampling tube to have a diameter of 80 mm.

[0079] A circular air outlet channel is provided on the top of the sampler 2 for discharging the internal air, and its diameter is 20mm. Four air inlets are provided on the upper side of the sampler, and the height and width of the rectangular tangential air inlet are 30mm and 20mm respectively. It is used to allow air to enter the sampler in the form of a cyclone. A sampling port is provided at the bottom of the sampler 2 for connecting a sampling tube, and the sampling tube is filled with a sampling liquid. At the same time, a filter with an aperture of 100μm is installed on the four air inlets of the sampler 2 to filter out impurities in the environment.

[0080] The sampling flow rate of the aerosol sampler can be adjusted steplessly using a knob between a maximum flow of 700L / min and a minimum flow of 30L / min.

[0081] The sampling time of the aerosol sampler can be freely set between 5 minutes, 10 minutes, 15 minutes, 30 minutes and no more than 99 minutes. At the same time, the LCD touch screen is used to control the sampling process and issue a sampling end reminder.

[0082] Formula (1) is configured in the main control circuit board to perform real-time integration and display the current accumulated sampled gas volume in real time.

[0083]

[0084] Where Q is the sampling air flow rate (m3 / s), dt is the sampling time (s), P is the pressure correction coefficient during sampling, and T is the temperature correction coefficient during sampling.

[0085] The sampled gas volume is calculated based on the above formula and is set using the main control circuit board to achieve precise control of the sampled gas volume, so that the LCD touch screen can display the current corrected sampled gas volume under standard atmospheric pressure at 25°C in real time.

[0086] In some embodiments, the aerosol sampling flow correction mechanism is that the main control circuit board adjusts the current flowing through the wind motor according to the flow rate signal to achieve constant sampling flow and maintain high sampling efficiency.

[0087] For example, the flow correction process adopts PID control. Figure 7 As shown, the PID control process is as follows: start sampling and collection, the main control circuit board obtains the current sampling speed, compares it with the set sampling speed, calculates the error between the current sampling speed and the set sampling speed, calculates the proportional link, calculates the differential link, calculates the integral link, and sums them up to get the output signal, converts the output signal into a current signal, transmits it to the brushless wind motor (an example of a specific model of the wind machine), realizes flow correction, and repeats the above steps iteratively during the sampling and collection process to realize PID control of the wind machine.

[0088] After the sampling is completed, the liquid sample is obtained and the sample is tested using a qPCR instrument, thereby obtaining the C t The value is combined with the sampled gas volume obtained earlier and the sampling efficiency of the aerosol sampler, and the Ct value is input on the LCD capacitive touch screen. The device uses the following formula to calculate the concentration of microbial pathogens in the aerosol. Specifically, as shown in formula (2):

[0089] ρ=f(C t )×V1 / Vη (2)

[0090] Where f(C t ) is the initial copy number obtained by searching the standard curve of fluorescence quantitative PCR, V1 is the sample volume (μL), and V is the corrected sampling gas volume at 25°C and one atmosphere (m 3 ), η is the aerosol sampling efficiency.

[0091] Based on the microbial pathogen aerosol sampling device described above, an embodiment of the present invention further provides a method for calculating pathogen concentration, which comprises the following steps:

[0092] S1. First, add 2 ml of sampling liquid to the sampling tube 3, then fix the sampling tube 3 on the sampling port 203 of the sampler 2, and finally fix the sampler 2 on the sampler housing 1.

[0093] S2, turn on the button switch 5, click the LCD capacitive touch screen 4, and set the working time and sampling rate or sampling gas volume of the environmental pathogenic microorganism aerosol sampling device.

[0094] S3, the fan 6 starts to run, and the external air enters the sampler 2 from the air inlet 202. Due to the rectangular tangential air inlet 202 and the conical shape of the sampler 2, the external air will form a cyclone vortex after entering the sampler 2. Under the influence of the cyclone vortex, the air will make a spiral rotation from top to bottom along the inner wall of the sampler 2. In this process, the aerosol particles in the air will be affected by the centrifugal force and gravity and move toward the sampling port 203. Then, when the vortex reaches the bottom of the sampler 2, that is, the top of the sampling tube 3, the air will rotate upward along the axis of the sampler 2. Finally, the air will be drawn out of the sampler 2 from the air outlet 201 by the fan.

[0095] S4. In order to keep the sampling flow constant during the sampling process, the device uses the built-in PID algorithm to adjust the current flowing through the fan according to the signal of the gas flow meter to maintain efficient and stable sampling efficiency.

[0096] S5. In order to calculate the volume of the collected gas in real time, the controller obtains the current gas flow signal in real time, and uses formula (1) to cumulatively calculate the current sampled gas volume value, and displays it in real time on the LCD touch screen;

[0097] S6. When the environmental pathogenic microorganism aerosol sampling device works for the set time or the sampling gas volume, the capacitive LCD touch screen 4 will display the information of the operation completion and the sampling gas volume, then remove the sampler 2 and the sampling tube 3, and take out the sample from the sampling tube 3 for qPCR test. The sampler 2 and the sampling tube 3 are sterilized and discarded. At this time, the LCD touch screen displays the waiting test end input C t value;

[0098] S7. After the qPCR reaction is completed, enter C t The device uses formula (2) according to the sample gas volume value, C t value, the sampling efficiency of the equipment, and the concentration value of the microbial pathogens are calculated.

[0099] Then click the return key of the LCD capacitive touch screen 4 to wait for the next sampling.

[0100] Finally use Figure 8 The process shown calculates the concentration of pathogens in the aerosol.

[0101] In summary, this embodiment uses the designed aerosol sampler, pressure sensor, temperature sensor, fan and gas flow meter to achieve variable flow rate sampling under the control of the main control circuit board. At the same time, the pressure sensor, temperature sensor and flow sensor are used to establish a calculation method for the sampled gas volume under standard atmospheric pressure at 25°C to achieve accurate control of the sampled gas volume. At the same time, the Ct value of the qPCR reaction is combined to calculate the concentration of microbial pathogens in the aerosol. The sampling wind speed of the present invention can reach up to 700L / min, and 7m can be sampled within 10 minutes. 3 The invention can also adjust the collected product to about 100-500 μL by regulating the sampling flow rate or sampling time, thereby concentrating the sampled liquid, and the sampled product can be directly used for nucleic acid detection.

[0102] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and should all be included in the scope of the claims and specification of the present invention.

Claims

1. A microbial pathogen aerosol sampling device, characterized in that: Including fan, sampler, sampling tube, sampler housing, touch screen, silicone seal, lithium battery pack, charging head, main control circuit board, base, gas flow meter, pressure sensor, temperature sensor, filter and hose; The sampler housing is connected to the base, and the sampler housing is used to fix the fan, gas flow meter, pressure sensor, temperature sensor, sampler, touch screen, lithium battery and charging head; The top of the sampler is provided with an air outlet, the upper side of the sampler is provided with at least two tangential air inlets, the bottom of the sampler is provided with a sampling port, the sampling port is connected to the sampling tube, and the air outlet is connected to the hose; The gas flow meter, pressure sensor, temperature sensor and filter are arranged on the hose; The lithium battery pack is connected to the charging head, the signal output ends of the gas flow meter, pressure sensor, and temperature sensor are connected to the signal input end of the main control circuit board, the signal output end of the main control circuit board is connected to the signal input end of the fan, the main control circuit board is connected to the touch screen signal, and the lithium battery pack is electrically connected to the main control circuit board; The silicone sealing ring is fixed on the top of the connection between the sampler housing and the sampler.

2. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: Filters are installed at the at least two tangential air inlets.

3. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: The connection between the sampler housing and the sampler is in a circular ring shape, and the inner ring is provided with an external thread for forming a threaded fit with the sampler. A fan fixing hole and a wire hole are provided on the top of the sampler housing. The diameter of the fan fixing hole is the same as the diameter of the fan and is used to fix the fan. The wire hole is used to lead the fan wire to the interior of the sampler housing. A plurality of bosses are provided on the inner side of the bottom of the sampler housing, and each boss is provided with a boss circular hole. The boss circular hole is concentric with the circular hole provided on the base and is used to connect the base.

4. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: It also includes a foam pad, which is arranged at the lower end of the base.

5. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: The diameter of the sampler is determined according to the cutting particle size; wherein the cutting particle size is the microbial aerosol particle size located on the cylindrical surface CS, and the cylindrical surface CS is a cylindrical surface inside the sampler extending downward from the exhaust direction to the bottom of the sampler, and the aerosol particles on the cylindrical surface CS are balanced.

6. The microbial pathogen aerosol sampling device according to claim 5, characterized in that: The cut particle size is determined by the following method: The tangential velocity and axial velocity on the cylindrical surface CS are determined according to the force of the microbial aerosol in the sampler; The forces acting on the microbial aerosol in the sampler include outward centrifugal force and inward airflow resistance, which are respectively expressed as: F stokes =3πχμv rCS In the formula, CF is the centrifugal force, x is the aerosol particle size, R X is the sampler radius, χ is the air viscosity, ρ p is the aerosol density, v θCS is the tangential velocity on the cylindrical surface CS, v rCS is the axial velocity on the cylindrical surface CS, F stokes is the inward airflow resistance, μ is the air viscosity; Based on the tangential velocity and axial velocity on the cylindrical surface CS, the cutting particle size is calculated by the following formula: In the formula, x 50 is the cutting particle size, D x is the sampler diameter.

7. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: The main control circuit board is configured to calculate the current cumulative sampled gas volume V based on the following formula: Where Q is the sampling air flow rate, dt is the sampling time, P is the pressure correction coefficient during sampling, and T is the temperature correction coefficient during sampling.

8. The microbial pathogen aerosol sampling device according to claim 1, characterized in that: The main control circuit board is configured to calculate the concentration p of microbial pathogens in the aerosol based on the following formula: ρ=f(C t )×V1 / Vη In the formula, f(C t ) is the initial copy number obtained by searching the standard curve of fluorescence quantitative PCR, V1 is the sample volume, V is the corrected sampling gas volume at 25°C and one atmosphere, and η is the aerosol sampling efficiency.

9. A method for calculating pathogen concentration, characterized in that: Based on the microbial pathogen aerosol sampling device according to any one of claims 1 to 8, the method comprises: Add sampling liquid into the sampling tube; Set the working time and sampling rate or sampling gas volume of the microbial pathogen aerosol sampling device; The fan is controlled to start running, and the external air enters the sampler from the air inlet. The external air will form a cyclone vortex after entering the sampler, and make a spiral rotation from top to bottom along the inner wall of the sampler. During this process, the aerosol particles in the air will be affected by centrifugal force and gravity and move toward the sampling port. When the vortex reaches the bottom of the sampler, the air will rotate upward along the axis of the sampler and be drawn out of the sampler from the air outlet by the fan; According to the signal from the gas flow meter, the current flowing through the fan is adjusted to maintain the set sampling efficiency; The current gas flow signal is obtained in real time through the main control circuit board, the current sampled gas volume value is accumulated and calculated, and displayed in real time on the touch screen; When the environmental pathogenic microorganism aerosol sampling device works for the set time or sampling gas volume, the sample is taken out from the sampling tube for qPCR testing; After the qPCR reaction is completed, in response to the input Ct value, the main control circuit board calculates the concentration value of the microbial pathogen based on the sampled gas volume value, Ct value, and the sampling efficiency of the equipment; among them, the Ct value is automatically displayed after the qPCR reaction is completed, which means the number of amplification cycles corresponding to when the fluorescence signal of the amplified product reaches the set fluorescence threshold.

10. The method for calculating pathogen concentration according to claim 9, characterized in that: When the environmental pathogenic microorganism aerosol sampling device works for a set time or samples a gas volume, the method further includes: The touch screen displays the information about the completion of the operation, the volume of the sampled gas, and the Ct value after the test is completed. Remove the sampler and sampling tube.

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