METHOD FOR DETECTING THE CONCENTRATION OF ORGANIC PARTICLES IN THE AIR AND APPARATUS THEREFOR

Abstract

A method for detecting concentration of organic particles (14), in particular viruses, with a determined target diameter in air (10) comprises organic and/or inorganic aerosol particles. Aerosol particles contained in the air (10) are bound in a fluid (40), so that said aerosol particles are contained as particles in the fluid (40). The fluid (40) with particles is exposed in measurement chamber (30) to a second light (B) fragmenting the organic particles and/or to an ultrasound (C) fragmenting the organic particles in the fluid (40). Before fragmentation of organic particles, a first light scattering of a first light (A) and after the fragmenting of organic particles, a second light scattering of the first light (A) on the fluid (40) are determined. Using difference between the first light scattering and the second light scatterings, the concentration of the organic particles (14) in the fluid (40) and thus in the air is determined.

Claims

1. A method for detecting a concentration of organic particles (14), in particular viruses, with a determined target diameter in air (10) which comprises organic and/or inorganic aerosol particles, wherein aerosol particles contained in the air (10) are bound in a fluid (40), so that said aerosol particles are contained as particles in the fluid (40), wherein the fluid (40) with the particles contained therein is exposed in a measurement chamber (30) to a second light (B) fragmenting the organic particles and/or to an ultrasound (C) fragmenting the organic particles, so that the organic particles are fragmented in the fluid (40), wherein before the fragmentation of the organic particles, a first light scattering of a first light (A) and after the fragmenting of the organic particles, a second light scattering of the first light (A) on the fluid (40) are determined, and, from a difference between the first light scattering and the second light scatterings, the concentration of the organic particles (14) in the fluid (40) and thus in the air is determined.

2. The method according to claim 1, wherein the fragmentation of the organic particles as well as the determination of the first light scatterings and of the second light scattering are carried out offset in time with respect to one another in a single measurement chamber (30).

3. The method according to claim 1, comprising the steps in the following order: a) binding aerosol particles contained in air (10) in the aqueous fluid (40), so that the fluid (40) contains the aerosol particles previously contained in the air (10) as particles; b) guiding the fluid (40) into the measurement chamber (30), which can be exposed to light (A, B) emitted by a light source (33); c) exposing the fluid (40) in the measurement chamber (30) to the first light (A) of first intensity and first wavelength, wherein the first intensity and the first wavelength are selected so that no organic particles are fragmented by the first light (A); d) determining the first light scattering of the first light (A) on the fluid (40) in the measurement chamber (30); e) exposing the fluid (40) in the measurement chamber (30) to the second light (B) of second intensity and second wavelength, wherein the second intensity and the second wavelength are selected so that the organic particles are fragmented by the second light (B), and/or exposing the fluid (40) in the measurement chamber (30) to ultrasound (C), wherein a frequency of the ultrasound is selected in such a manner that the organic particles are fragmented; f) exposing the fluid (40) in the measurement chamber (30) to the first light (A); g) determining the second light scattering of the first light (A) on the fluid (40) in the measurement chamber (30); h) determining the difference between the first light scattering and the second light scattering, and determining the concentration of the organic particles (14) in the fluid (40) from the difference between the first light scattering and the second light scattering.

4. The method according to claim 3, wherein the wavelength and the intensity of the second light (B) are set or selected in such a manner that the wavelength is in a range which excites a vibration of the organic particles (14), so that the organic particles (14) with the target diameter in the fluid (40) are set in vibration and comminuted.

5. The method according to claim 3, wherein the first light (A) and the second light (B) are each a laser beam which radiates through the measurement chamber (30) along a first direction.

6. The method according to claim 1, wherein the first light scattering and the second light scattering are detected orthogonally to the first direction by an optical sensor (32).

7. The method according to claim 6, wherein the optical sensor (32) is a camera system for detecting a light scattered by the Tyndall effect on the fluid (40).

8. The method according to claim 1, wherein a flow of the fluid (40) through the measurement chamber (30) is controllable and is controlled during the fragmentation and the determination of the first and second light scatterings in such a manner that the fluid (40) is free of flow in the measurement chamber (30).

9. The method according to claim 1, furthermore comprising, before the binding of the aerosol particles contained in the air (10) in the fluid (40), the step: guiding air in a sized filter (21, 22) by which aerosol particles (11, 12) having a diameter greater than the target diameter are filtered out, so that filtered air is obtained, which contains aerosol particles with a diameter equal to and/or smaller than the target diameter, so that the fluid (40), during the binding of the aerosol particles contained in the air (10) in the fluid (40), contains the aerosol particles with a diameter equal to or smaller than the target diameter that were previously contained in the filtered air.

10. The method according to claim 1, furthermore comprising, before the binding of the aerosol particles contained in the air (10) in the fluid (40), the step: guiding air into a charge filter (23), by means of which aerosol particles which have a positive charge and/or aerosol particles which have a negative charge and/or aerosol particles which have no charge are filtered out of the air (10), so that filtered air is obtained, which contains aerosol particles with a predetermined charge, so that, during the binding of the aerosol particles contained in the air (10) in the fluid (40), the fluid (40) contains as particles the aerosol particles with a predetermined charge that were previously contained in the filtered air.

11. The method according to claim 1, furthermore comprising, before the binding of the aerosol particles contained in the air (10) in the fluid (40), the step: guiding air (10) into an inhomogeneous electric field (24) by means of which polarizable aerosol particles are polarized and which is designed to guide the polarized aerosol particles onto a collection apparatus, wherein the polarized aerosol particles accumulate on the collection apparatus and are bound on said collection apparatus or coming out of said collection apparatus during the binding of the aerosol particles contained in the air (10) in the fluid (40).

12. The method according to claim 1, wherein the aerosol particles contained in the air (10), during the binding in the fluid (40), are bound by formation of a condensate from the air in the fluid (40).

13. The method according to claim 1, wherein the first light and/or the second light (44) is/are pulsed during the irradiation of the fluid (40).

14. An apparatus for carrying out the method according to claim 1, comprising at least one prefilter (1) and in each case a measurement unit (2) as well as in each case an evaluation unit, wherein the prefilter (1) is designed to guide air (10) comprising organic and/or inorganic aerosol particles to the measurement unit (2), wherein the measurement unit (2) or the prefilter (1) comprises an apparatus (31) for binding the aerosol particles in a fluid (40) wherein the fluid (40) can flow through the measurement unit along a flow path and the flow of the fluid (40) is controllable, wherein the measurement unit (2) comprises a measurement chamber (30) and a light source (33), wherein the light source (33) is designed to emit the first light (A) and the second light (B) with the respective intensity and the respective wavelength offset in time with respect to one another, wherein the measurement unit (2) furthermore comprises an optical sensor (32) for determining the first light scattering and the second light scattering of the first light (A) on the fluid (40) in the measurement chamber (30), and wherein the evaluation unit is designed to determine, from a difference between the first light scattering and the second light scattering, a concentration of the organic particles (14) having the determined target diameter in the air (10).

15. A method for determining a concentration distribution and/or a movement pattern of an aerosol with organic particles with a target diameter in a room using the apparatus according to the preceding claim, wherein the apparatus comprises a plurality of units respectively formed by a prefilter (1), a measurement unit (2) and an evaluation unit, and wherein the units are arranged according to a predetermined pattern in the room, wherein, from the concentrations of the particles (14) with the target diameter, which concentrations can be determined by the individual units, in combination with the arrangement of the respective units according to the pattern, a position of an aerosol cloud in the room is determined, wherein, as a result of positions of the aerosol cloud, which are determined successively in time, a previous movement path and, on the basis of an interpolation, a future movement path of the aerosol cloud are determined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS:

[0063] Additional advantageous developments of the example embodiments of the disclosure are characterized in the dependent claims or represented in further detail below based on the figures together with the description of the preferred embodiment of the disclosure the figures. In the figures:

[0064] FIG. 1 shows an apparatus for carrying out the method according to an example embodiment of the disclosure; and

[0065] FIG. 2 shows a prefilter comprising multiple filter stages according to an example embodiment of the disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS:

[0066] The figures are diagrammatic examples, wherein FIG. 2 shows a prefilter 1 consisting of multiple filter stages, which prefilter can be connected upstream to the apparatus 2 represented in FIG. 1.

[0067] The method according to the an example embodiment of the disclosure as well as the associated sensor according to an example embodiment or the associated apparatus according to an example embodiment, which are illustrated diagrammatically in FIG. 1, are used for detecting inorganic and organic particles having a determined diameter, wherein, in a method run, in each case particles 14 with a target diameter can be detected, and this target diameter can be varied substantially by setting the wavelength and the intensity of the light emitted by the light source during the fragmentation of the particles, which corresponds to the second light, as well as by an adaptation of the evaluation based thereon.

[0068] The backdrop of example embodiments of the disclosure is the detection of particles with these properties—that is with a previously known diameter which corresponds to the target diameter within a tolerance range—in terms of their concentration and their possible display or issuing of a warning message.

[0069] The basic principle consists of the differential measurement of the scattering capability of the particles with their original properties, wherein a particle, which can be a virus, thus has not yet been comminuted, in comparison to the scattering capability of the particles or the particle fragments thereof, which have been irradiated with the second light and comminuted thereby. This difference gives information on the concentration of the particles in the air, which is the basis of the measurement.

[0070] According to the proposed method, in order to be able to bind aerosol particles contained in the air in the fluid 40 according to the proposed method, a collection apparatus 31 is provided, which, according to FIGS. 1 and 2, is designed, for example, as a Peltier element, on the cold side 31′ of which the air with the particles can condense, and on the hot side 31″ of which the fluid 40 is evaporated again and discharged again via released air 41. Moreover, by the evaporation on the hot side, a suction is generated, which conveys the flow of the fluid 40 through the inlet 34 of the measurement chamber 30 into the measurement chamber 30 and, after the method, out of the outlet 35 out of the measurement chamber 30, wherein the suction or the flow can be controlled, for example, by a valve which is not shown.

[0071] The particles floating in the condensate or in the fluid 40, which can be, for example, the Covid-19 virus or another pathogen, then preferably reach the measurement chamber 30 of the measurement unit 2 due to capillary action. The flow of the fluid 40 is controlled for this purpose in such a manner that the fluid, while the method is carried out, exhibits substantially no flow, that is to say no fluid 40 flows out of the measurement chamber 30 and also no new fluid 40 additionally flows into the measurement chamber 30.

[0072] Then, in the measurement chamber 30, due to the light source 33 formed here as a laser, a first light A is emitted through the measurement chamber 30, which light is selected so that the organic particles are not fragmented in the fluid 40. The first light A is scattered as a result of the Tyndall effect on the particles or on all the particles in the fluid 40 in the measurement chamber 30, wherein the light scattering is measured by the optical sensor 32. In the present case, the optical sensor 32 is formed as a camera system for image processing of the Tyndall scattering with an upstream camera tube 39, in which a camera optical system for focusing the image recorded by the camera system is arranged. Here, the camera system or the optical sensor 32 is darkened with respect to the surrounding environment and only connected via a light-permeable window 36 to the measurement chamber, wherein the window 36 does not reflect light or is reflection-free, so that the measurement is not distorted by the optical sensor 32.

[0073] The laser or the light source 33 as well is separated from the measurement chamber 30 by means of such a window 36, wherein the laser beam or the first and second lights A, B in turn exit from the measurement chamber 30 on the opposite side of the measurement chamber 30 through such a window 36 and strike an absorber 37, by means of which the light can be absorbed and preferably the strength or the intensity of the light can also be measured, which facilitates or allows the control of the light source 33.

[0074] After the first light scattering has been measured by means of the optical sensor 32, the fragmentation of the organic particles in the fluid 40 occurs, which is brought about by an exposure of the fluid 40 to the second light B and here, in addition, by the exposure of the fluid 40 to ultrasound C. For this purpose, within the measurement chamber 30, multiple ultrasound generators 38 are additionally provided, which generate ultrasound C at least in the region relevant to the measurement of the light scattering and thereby contribute to the fragmentation of the organic particles in the fluid 40.

[0075] Here, all the particles in the fluid 40 are exposed to the second light B as well as to the ultrasound C, wherein, due to the adjustment of the intensity and the wavelength of the second light B and of the frequency of the ultrasound C in connection with an optional pulsing of the ultrasound C and of the second light B, in particular the organic particles with the target diameter are fragmented, and, for example, any inorganic particles or particles with smaller diameter than the target diameter that are present are not fragmented.

[0076] After the fragmentation, which can be carried out for a predetermined time, a second measurement of the light scattering occurs, wherein the second light scattering measured here is compared to the first light scattering. From the difference between the light scatterings, a conclusion can be drawn as to whether and how many particles have been fragmented and accordingly how many organic particles with the target diameter are or were present in the fluid 40.

[0077] Since the quantity of air the fluid 40 was obtained from is known, the proportion of the organic particles with the target diameter in the air and whether this proportion or this concentration exceeds a predetermined limit value can be determined.

[0078] In FIG. 2, a prefilter 1 provided for the collection and cleaning of the air is represented. A plurality of different particles 11, 12, 13, 14 are collected, which are contained in the air 10. The particles 11, 12, 13, 14, which are usually in fluid droplets, in the aerosol, are bound for this purpose in a fluid 40.

[0079] In the present case, a first sized filter 21 is provided as coarse filter which filters particles 11 which are substantially larger than particles 14 with the target diameter. Next in flow direction of the air 10, a second sized filter 22 is provided as fine filter, which filters particles 12 which have a diameter greater than the target diameter and a diameter smaller than the particles 11 filtered by the first sized filter 21. Subsequently, a charge filter 23 is provided, which, for example, is implemented by a targeted electric field, by which all the positively or negatively charged particles 13 are filtered from the air, wherein said particles, due to the first and second sized filters 21, 22, have a diameter equal to or smaller than the target diameter. Depending on the environmental conditions or the target diameter of the particle, additional filters and, for example, more sized filters, can also be provided additionally. The remaining particles are polarized to the extent possible by the apparatus 24. The polarized particles 14 are deflected by the apparatus 24, for example, an inhomogeneous electric field, onto a collection apparatus and are collected on said collection apparatus for further analysis. The particles 15 remaining in the air can be expelled again, since they are of no interest for the analysis. The particles 14 collected in this way for further analysis are all the particles which were not filtered out previously by the different filters or filter stages, so that, in addition to the organic particles with the target diameter, the proportion of which in the air is to be determined, additional particles can also be bound in the fluid. The air flow can be driven through the prefilter 1 or through the filter and the polarization apparatus by a fan, not shown, which generates a continuous air flow with a preferably known volume flow. By means of the first and second sized filters 21, 22, preferably all the particles having a diameter greater than the target diameter, that is to say greater than the potential virus diameter of, for example, 300 nm, are filtered out.

[0080] Example embodiments of the disclosure are not limited to the above indicated preferred embodiment examples. Instead, a number of variants are conceivable, which use the represented solution even in embodiments of fundamentally different type.