LU503125B1

LU503125B1 - Electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device

Info

Publication number: LU503125B1
Application number: LU503125A
Authority: LU
Inventors: Xuezheng Ma
Original assignee: Chinese Acad Inspection & Quarantine
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2023-06-05

Abstract

An electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device, characterized by comprising a bracket, an axial fan, an air outlet cavity, a collector, a power electronic unit and an excitation coil group; the collector, the air outlet cavity and the axial fan are fixedly arranged on the bracket, the air outlet cavity is sleeved in the collector, and the collector is used for placing collecting liquid; the axial fan is arranged above the air outlet cavity, is used for collecting the gas sample to be detected, and inputs the gas sample into the collecting liquid of the collector through the air outlet arranged at the lower end of the air outlet cavity; the excitation coil group is connected with the power electronic unit, is used for generating a rotating magnetic field, and is arranged outside the collector and inside the bracket. The instrument of the invention generates a rotating magnetic field through the excitation coil, controls the immunomagnetic beads to rotate in the collecting liquid, and increases the probability of meeting aerosol. The invention can efficiently capture microbial aerosol in the air, and at the same time, it can specifically realize the enrichment of microbial samples, and is especially suitable for monitoring microbial pathogens in ambient air.

Description

ELECTRIC MAGNETIZATION MAGNETIC BEAD ROTATING

MICROBIAL AEROSOL COLLECTING AND ENRICHING DEVICE

TECHNICAL FIELD

The invention relates to a microbial aerosol collecting and enriching device, in particular to an electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device.

BACKGROUND

Human infectious diseases and animal epidemic diseases have been affecting human health, disturbing international travel, trade and the economic development of animal husbandry, and even being used as bioterrorism factors to affect social stability.

The culprit of human infectious diseases and animal epidemic diseases, pathogenic microorganisms, often exist in the bottom of the atmosphere in the form of aerosol, which will bring large-scale threats to human health and animals when reaching a certain concentration, such as SARS, HIN1 flu, MERS, H7N9 flu, HSN1 avian influenza, foot-and-mouth disease, African swine fever, etc. Therefore, timely, simple and accurate monitoring of micro-organisms in the air environment is of great significance to the protection of people's health and animals.

Efficient and comprehensive sampling is the premise of accurate detection of airborne microorganisms. Conventional sampling methods of airborne microorganisms mainly include the following three methods: sampling based on solid culture medium, sampling based on physical effects and characteristics, and sampling based on liquid sampling medium. Among them, the solid medium sampling method is difficult to reflect the real situation of air microbial composition in time, comprehensively and accurately, and the physical function and characteristic sampling method is unfavourable to the survival of microorganisms, and the operation is relatively complicated and takes a long time. The sampling method based on liquid medium is widely used in the industry. The liquid has a certain protective effect on microorganisms, which can avoid the death of microorganisms caused by violent impact during the collection process.

Liquid sampling methods can be divided into: impact method, cyclone method, magnetic bead assisted cyclone method, etc. Impact method collects microbial particles in the air in a small volume of liquid by jet air. Cyclone method uses the high-speed flow of air to push the collecting liquid to form a vortex, which dissolves the particulate matter in the air into the collecting liquid. Magnetic bead assisted cyclone method puts nanometre immunomagnetic beads into the collection solution, and cooperates with cyclone device to collect and enrich aerosol better.

In the aerosol monitoring of infectious diseases, the practicability of the above three kinds of liquid medium collectors needs to be further improved. The main reasons can be summarized as follows: 1) The collection efficiency is low, the aerosol can't fully contact with the collection liquid, so it is difficult to be collected by the collection liquid, and it is easy to cause re-loss; Nanomagnetic beads are used to adsorb viruses in the enrichment process, and the relative movement speed of single magnetic bead and aerosol particles is low, which is close to the static state, resulting in low spatial contact probability, unsatisfactory enrichment rate and easy to lead to false negative results. 2) The power consumption per unit time is large, and the sustainable working time under the pure battery power supply state is short, only 10-90 minutes, so it is not suitable for field operation with external power supply and special environment operation. At the same time, due to this limitation, the total flux of the existing collector design is low, and it is difficult to collect enough air samples, which reduces the detection rate of bacteria and viruses. 3) Poor portability. Most devices weigh 20-40 kg and the volume is about 10-30

L, which makes it difficult to carry, and increases the difficulty of single-person operation and multi-device multi-point cooperative operation.

The sampling efficiency, power consumption and portability of the existing microbial aerosol collector still need to be improved, and there is still room for development from the practical application.

SUMMARY

The purpose of the invention is to provide an electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device to solve the technical problems of low sampling efficiency, large power consumption, difficulty in carrying and the like of the existing microbial aerosol collecting device.

An electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device comprises a bracket, an axial fan, an air outlet cavity, a collector, a power electronic unit and an excitation coil group; the collector, the air outlet cavity and the axial fan are fixedly arranged on the bracket, the air outlet cavity is sleeved in the collector, and the collector is used for placing collecting liquid; the collection liquid is a test liquid with immunomagnetic beads, which can capture microorganisms carried by the gas to be tested, and the upper liquid level of the collection liquid needs to exceed the bottom plane of the lower end of the gas outlet cavity during testing; the axial fan is arranged above the air outlet cavity, is used for collecting the gas sample to be detected, and inputs the gas sample into the collecting liquid of the collector through the air outlet arranged at the lower end of the air outlet cavity; the excitation coil group is connected with the power electronic unit, is used for generating a rotating magnetic field, and is arranged outside the collector and inside the bracket.

Optionally, the air outlet cavity is a cavity with an inverted conical opening at the upper part and a cylindrical shape at the lower part, and several air outlet pipelines are arranged on the bottom surface of the lower part; all the air outlet pipelines are uniformly distributed relative to the axis of the air outlet cavity, and the axes of all the air outlet pipelines are parallel to the axis of the air outlet cavity.

Optionally, the number of the air outlet pipes is more than or equal to 12, and the total cross-sectional area of all the air outlet pipes is greater than 1/3 of the cross-sectional area of the cylindrical part at the lower end of the air outlet cavity.

Optionally, the bottom surface of the lower end of the air outlet cavity 1s set as a horizontal plane.

Optionally, the collector is a container with an inverted conical upper end and a cylindrical lower end, and the cylindrical capacity is more than or equal to 15 ml.

Optionally, the outer edge of the top of the collector, which has an inverted cone shape at the upper end, expands into a square, and the square is provided with an installation hole fixed with the bracket.

Optionally, the axial fan, the air outlet cavity, the collector and the central axis of the excitation coil group coincide, and the height of the excitation coil group is the same as the central height of the collector when the collecting liquid is placed in the collector at rest.

Optionally, the excitation coil group is composed of six groups of excitation windings, and their spaces are annular and symmetrically distributed. Each excitation winding is composed of three excitation coils, and their vertical centre heights are consistent.

Optionally, the microbial aerosol collector also comprises a battery, the battery is connected with a power electronic unit, the power electronic unit converts the direct current supplied by the battery into three-phase alternating current, and generates a rotating magnetic field through the excitation coil group, and the axial fan is connected with the battery.

Optionally, the collection liquid is a test liquid with immunomagnetic beads, which can capture microorganisms carried by the gas to be measured, and the upper liquid level of the collection liquid needs to exceed the bottom plane of the lower end of the gas outlet cavity during the test.

According to the electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device, aerosol is collected in a gas-liquid mixing square mode, and the immunomagnetic beads are put into the collection liquid to be detected to capture microorganisms carried by the gas to be detected, and the rotating magnetic field generated by the excitation coil group controls the rotation of the immunomagnetic beads, so that the probability of meeting and adsorbing the 5 immunomagnetic beads with aerosol is increased.

For the convenience of field operation, the device is also provided with a battery, which can directly supply power to the power electronic unit to generate three-phase alternating current, and generate a rotating magnetic field through the excitation coil group. The device has simple structure, coherent operation links and simple implementation, effectively shows that the enrichment mode of pathogenic microorganisms is connected with the existing microbial detection method, and is simple, time-saving, labour-saving and convenient to carry.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is a schematic structural diagram of a preferred embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an air outlet chamber in a preferred embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an air outlet chamber in a preferred embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a collector in a preferred embodiment of the present invention.

Fig. 5 is a schematic diagram of the spatial position of the excitation coil group in a preferred embodiment of the present invention.

Fig. 6 is a schematic circuit diagram of a power electronic unit in a preferred embodiment of the present invention.

Fig. 7 is a schematic diagram of the electrical connection of the excitation coil group in a preferred embodiment of the present invention.

DESCRIPTION OF THE INVENTION

It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The invention will be described in detail below with reference to the attached drawings and examples. The attached drawings are for reference and illustration only, and should not be construed as limiting the scope of patent protection of the invention.

In order to solve the problems of low sampling efficiency, large power consumption, difficulty in carrying and the like of the existing microbial aerosol collector, the invention provides an electric magnetization magnetic bead rotating microbial aerosol collector, which comprises a bracket, an axial fan, an air outlet cavity, a collector, a power electronic unit and an excitation coil group; the collector and the air outlet cavity are arranged on the bracket, the air outlet cavity is sleeved in the collector, and the collector is used for placing collecting liquid; the axial fan is arranged above the air outlet cavity and used for collecting the gas sample to be detected; the gas sample is input into the collecting liquid of the collector through the gas outlet cavity, and the excitation coil group is connected with the power electronic unit, and is used for generating a rotating magnetic field, and is arranged outside the collector and inside the bracket.

When in use, the collection liquid for capturing microbial magnetic beads is placed in the collector, and the collection liquid does not pass through the air outlet of the air outlet cavity, and the axial fan sucks the gas sample to be measured into the air outlet cavity, and then ejects the collection liquid from the air outlet cavity into the closed collector, so that the gas sample can fully contact with the collection liquid; the excitation coil group generates a rotating magnetic field, which can control the immunomagnetic beads in the collection liquid to rotate, increase the contact probability between the gas sample and the collection liquid, improve the detection efficiency, and effectively avoid false negative results.

As shown in Fig. 1, the microbial aerosol collecting and enriching instrument of the present invention includes a bracket 1, an axial fan 2, an air outlet chamber 3, a collector 4, a power electronic unit 5 and an excitation coil group 6, and the upper and lower directions are set according to the use state of the collecting and enriching device, that is, the collector 4 is located below the air outlet chamber 3, and is detachably arranged. The axial fan 2, the air outlet chamber 3 and the collector 4 are all arranged on the bracket 1, that 1s, the bracket 1 1s used for fixedly placing the axial fan 2, the air outlet chamber 3 and the collector 4. The axial fan 2 is arranged above the air outlet chamber 3, which 1s sleeved in the collector 4. The axial fan 2 transports the gas to be measured into the air outlet chamber 3, and then injects it into the collector 4 through the air outlet at the lower end of the air outlet chamber. The excitation coil group 6 is connected with the power electronic unit 5, and is used for generating a rotating magnetic field, which 1s arranged outside the collector 4 and inside the bracket 1.

The upper part of the air outlet cavity is an inverted conical opening and the lower part is a cylindrical cavity, and a plurality of air outlets are arranged on the bottom surface of the lower part; all the air outlets are uniformly distributed relative to the axis of the air outlet cavity, and the axes of all the air outlets are parallel to the axis of the air outlet cavity. Specifically, as shown in fig. 2 and fig. 3, the air outlet chamber 3 is a chamber, and its upper part is an inverted cone-shaped cylinder 301, and its lower part is a cylindrical cylinder 302. The upper end of the inverted cone-shaped cylinder 301 is open, and the lower end of the inverted cone-shaped cylinder 301 is connected with the upper end of the cylindrical cylinder 302. The bottom surface 303 of the lower end of the cylinder 302 is horizontal, and the bottom surface 303 is provided with several air outlet pipes 304, which are uniformly arranged relative to the axis of the air outlet chamber 3. The axes of all air outlet pipes are spatially separated from the axis of the air outlet chamber 3, that is to say, the axis of the air outlet pipes is parallel to the axis of the air outlet chamber 3. The number of air outlet pipes 304 is not less than 12, preferably 20-64, and the total cross-sectional area of the air outlet pipes is greater than 1/3 of the cross-sectional area of the cylindrical barrel 302. The gas outlet pipe 304 is directly processed on the bottom surface of the gas outlet chamber 3, which is convenient to process, and can ensure that the spraying direction of the gas to be measured is unchanged in the spraying process, and can effectively and fully contact with the sampling liquid. The air outlet pipeline is short, not easy to block and easy to clean; the number of outlets is large, and the total area of outlets is large. On the one hand, the total amount of aerosol particles in contact with the collecting liquid per unit time 1s ensured, and on the other hand, the pressure difference required by the whole airflow system of the collecting and enriching instrument is reduced. The power of conventional fan is determined by pressure difference and flow rate. In the case of low pressure difference, the fan with smaller power can also provide sufficient gas flow rate, which is convenient to realize the balance between collection rate and power consumption.

The collector is set as a container with an inverted cone-shaped upper end and a cylindrical lower end, and the capacity of the cylindrical part is greater than or equal to 15mL. Specifically, as shown in Fig. 4, the collector 4 is a container whose upper end is composed of an inverted cone-shaped cylinder 401 and a cylindrical cylinder 402 arranged below. The upper end of the inverted cone-shaped cylinder 401 is open, the lower end is connected with the cylindrical cylinder 402, and the lower end of the cylindrical cylinder 402 is closed for holding the collecting liquid. The outer edge of the top of the inverted cone 401 is expanded into a square shape, and the square frame is provided with a mounting hole 403, which is convenient to fix with the bracket 1 and disassemble. The cylinder 402 is mainly used to store the collecting liquid.

When the collecting and enriching instrument of the invention is used, the added collecting liquid requires that the upper liquid level of the collecting liquid should be higher than the bottom surface 303 of the lower end of the air outlet chamber 3, and the collecting liquid capacity should be no less than 15 ml. This structure can ensure that a sufficient amount of collect liquid is mixed with a large-flow air sample, and avoid that loss of aerosol caused by the rapid evaporation of the collected liquid. The collection liquid is provided with immunomagnetic beads, and the microorganisms carried by the gas to be measured are captured and enriched by immunomagnetic beads.

Under the fixed action of the bracket 1, the axial fan 2, the air outlet chamber 3 and the collector 4 are overlapped with the central axis of the excitation coil group 6, and the central height of the excitation coil group 6 should be as consistent as possible with the central height of the collected liquid when it is still. As shown in fig. 5, the excitation coil group 6 of the collecting and enriching instrument is composed of a first winding 601, a second winding 602, a third winding 603, a fourth winding 604, a fifth winding 605 and a sixth winding 606, which are distributed symmetrically in a ring shape in space. Each excitation winding 601-606 is composed of three excitation coils, and their vertical centre heights are consistent.

In order to facilitate the use of the instrument in the field or in the absence of commercial power, the microbial aerosol collection and enrichment instrument is also provided with a battery, which is connected to the power electronic unit, which is connected to the excitation coil group, and the axial fan is directly connected to the electric cell. As shown in fig. 1, the power electronic unit 5 is arranged below the excitation coil group 6, and the battery 7 is arranged on the left side of the power electronic unit 5. Preferably, the battery is a rechargeable battery.

As shown in fig. 6, the electronic unit includes a bus capacitor C1, a first insulated gate bipolar transistor MOSFET Ql, a second insulated gate bipolar transistor MOSFET Q2, a third insulated gate bipolar transistor MOSFET Q3, a fourth insulated gate bipolar transistor MOSFET Q4, a fifth insulated gate bipolar transistor

MOSFET Q5, a second insulated gate bipolar transistor MOSFET Q6, a first power diode D1, The second power diode D2, the third power diode D3, the fourth power diode D4, the fifth power diode DS, and the sixth power diode D6 are connected to form a conventional inverter circuit. As shown in fig. 6, the left side of the power electronic unit 5 is a DC terminal connected with rechargeable batteries, and the right side is an AC terminal with three-phase circuits, which are respectively connected with the three-phase circuits of the excitation coil group 6. The base of each insulated gate bipolar transistor 1s connected with a PWM signal controller, and a driving signal is given to each insulated gate bipolar transistor through the PWM signal controller.

When the collecting and enriching instrument starts to work, the power electronic unit converts the direct current supplied by the battery 7 into three-phase alternating 5 current through the conventional SPWM control method, and generates a rotating magnetic field through the excitation coil group 6.

As shown in Fig. 7, the excitation coil group 6 is divided into three phases, which are respectively connected to the three AC output terminals of the power electronic unit 5. The first winding 601 and the fourth winding 604 are the first phase, the second winding 602 and the fourth winding 605 are the second phase, and the second winding group 602 and the fourth winding 605 are the third phase. One end of the three-phase windings of the excitation coil group 6 is connected to the output side of the power electronic unit 5, and the other ends of the three-phase windings of the excitation coil group 6 are connected together to form a midpoint.

When testing, the microbial aerosol collecting and enriching instrument of the present invention is placed in the area to be tested, the axial fan 2 is started, and the gas to be tested is pumped into the gas outlet chamber 3, and the gas to be tested is ejected from the gas outlet pipe 304 arranged on the bottom surface 303 of the gas outlet chamber 3, and sprayed into the collecting liquid in the collector 4. As several outlet pipes 304 are located on the bottom surface 303 of the collector 4, and their outlets are vertically downward, the formation of rotating airflow can be reduced and the pressure difference required by the axial fan can be reduced when gas is sprayed into the collector 4. All the collected gases to be measured can be completely sprayed into the collection liquid and mixed, so as to realize the efficient collection of aerosol and the collection liquid in the air. At the same time, the excitation coil group 6 generates a rotating magnetic field to control the rotation of immunomagnetic beads in the collection solution, and increase the probability of contact and enrichment between immunomagnetic beads and aerosol. After the gas collection, remove the gas outlet chamber 3 from the collector 4 from above, and modify it. The operation mode of the power electronic unit 5 is changed to form the same three-phase DC current, and a fixed magnetic field is generated by the excitation coil group 6. At this time, after all the immunomagnetic beads in the collection liquid adhere to the side wall of the collector 4 by magnetic force, the collection liquid can be sucked out by instruments such as straws and suction balls, and the magnetic beads enriched with microorganisms can be kept on the tube wall for the next microbial detection.

The test results of simulated air aerosol by using the microbial aerosol collecting and enriching instrument of the invention show that the instrument can accurately, quickly and efficiently collect and enrich microorganisms in aerosols such as ambient air.

The electric magnetization magnetic bead rotating microbial aerosol collecting and enriching instrument of the invention has the following advantages: 1. The design of the air outlet cavity conforms to the principle of fluid mechanics, and the total area of the air outlet is large, which on the one hand ensures the total amount of aerosol particles in contact with the collecting liquid in a unit time, and on the other hand reduces the pressure difference required by the whole air channel of the instrument; 2, several outlet pipes have the same cavity and short pipe layout, so that the outlet pipes of the outlet cavity are not easy to block and easy to clean; 3. The collector is an inverted cone and cylinder combined cavity, which is convenient for assembling and disassembling the air outlet cavity; 4. The collector has a large volume of liquid samples, which can match the collection of larger atmospheric flow. Immunomagnetic beads for microbial capture are directly added to the collected liquid, and the immunomagnetic beads are controlled to rotate through electric magnetization, so that the microbes in aerosol can be captured while gas and liquid are mixed.

The above is only a preferred embodiment of the present invention, and it is not intended to limit the present invention in other forms. Any person familiar with this field may use the technical content disclosed above to make changes or modifications to equivalent embodiments.

However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical scheme of the present invention still belong to the protection scope of the technical scheme of the present invention.

Claims

1. An electric magnetization magnetic bead rotating microbial aerosol collecting and enriching device, characterized by comprising a bracket, an axial fan, an air outlet cavity, a collector, a power electronic unit and an excitation coil group; the collector, the air outlet cavity and the axial fan are fixedly arranged on the bracket, the air outlet cavity is sleeved in the collector, and the collector is used for placing collecting liquid; the collection liquid is a test liquid with immunomagnetic beads, which can capture microorganisms carried by the gas to be tested, and the upper liquid level of the collection liquid exceeds the bottom plane of the lower end of the gas outlet cavity during testing; the axial fan is arranged above the air outlet cavity, is used for collecting the gas to be detected, and inputs the gas into the collecting liquid of the collector through the air outlet arranged at the lower end of the air outlet cavity; the excitation coil group is connected with the power electronic unit, is used for generating a rotating magnetic field, and is arranged outside the collector and inside the bracket.

2. The microbial aerosol collecting and enriching device according to claim 1, characterized in that the air outlet cavity is a cavity with an inverted conical opening at the upper part and a cylindrical shape at the lower part, and several air outlet pipelines are arranged on the bottom surface of the lower part; all the air outlet pipelines are uniformly distributed relative to the axis of the air outlet cavity, and the axes of all the air outlet pipelines are parallel to the axis of the air outlet cavity.

3. The microbial aerosol collecting and enriching device according to claim 2, characterized in that the number of the air outlet pipes is more than or equal to 12, and the total cross-sectional area of all the air outlet pipes is greater than 1/3 of the cross-sectional area of the cylindrical part at the lower end of the air outlet cavity.

4. The microbial aerosol collecting and enriching device according to claim 3, characterized in that the bottom surface of the lower end of the air outlet cavity is set as a horizontal plane.

5. The microbial aerosol collecting and enriching device according to claim 1, characterized in that the collector is a container with an inverted conical upper end and a cylindrical lower end, and the cylindrical capacity is more than or equal to 15 ml.

6. The microbial aerosol collecting and enriching device according to claim 5, characterized in that the outer edge of the top of the collector has an inverted cone shape at the upper end, expands into a square, and the square is provided with an installation hole fixed with the bracket.

7. The microbial aerosol collecting and enriching device according to claim 1, characterized in that the axial fan, the air outlet cavity, the collector and the central axis of the excitation coil group coincide, and the height of the excitation coil group is the same as the central height of the collector when the collecting liquid is placed in the collector at rest.

8. The microbial aerosol collecting and enriching device according to claim 1, characterized in that the excitation coil group is composed of six groups of excitation windings, and they are annular and symmetrically distributed; each excitation winding is composed of three excitation coils, and vertical centre heights are consistent.

9. The microbial aerosol collecting and enriching device according to any one of claim 1-8, characterized in that the microbial aerosol collector also comprises a battery, the battery is connected with a power electronic unit, the power electronic unit converts the direct current supplied by the battery into three-phase alternating current, and generates a rotating magnetic field through the excitation coil group, and the axial fan is connected with the battery.