EA027302B1 - Air disinfection method and device for implementation thereof - Google Patents

Abstract

The invention relates to methods for air disinfection of microorganisms and biological agents by the method of their inactivation by electrostatic fields and filtering by the method of electrostatic precipitation. The method comprises the steps of creating a flow (A) of air to be disinfected; subjecting said flow to constant with electrostatic fields alternating in direction of intensity vector, said electrostatic fields being sequentially arranged along the flow, and created by transversely spaced air permeable electrodes (1); and filtering the treated flow with an electrostatic filter. Electrostatic field concentrators in the form of projections (3) are located on the surface of the electrodes (1), in particular nanoscale projections, and the intensity of each of the alternating electrostatic fields between the electrodes is selected in accordance with the condition of electroporation of microorganism cells or their inactivation. A device for implementing this method is also claimed. The use of the invention provides a fast, effective, and reliable cleaning of air from any kind of microorganisms and viruses, as well as the aerosol particles having size of 0.08 μm. The invention also provides improved hygienic safety due to microorganism inactivation before the filtration step, and because of the absence of dangerous concentrations of ozone and other harmful substances.

Description

The invention relates to the field of disinfection and purification of air from microorganisms and aerosols, and in particular to methods of disinfecting air from microorganisms and biological agents by their inactivation by exposure to constant electric fields and filtration by electrostatic deposition.

The invention can be used for disinfection and purification of air in the supply and exhaust ventilation systems of biologically clean rooms in medicine, pharmaceutical, microbiological, food industry and other areas where it is necessary to ensure infectious and sanitary-epidemiological safety of the air. In addition, the invention can be used for air disinfection in vehicles, including passenger transportation by road and rail, air transportation, space manned flying vehicles, water surface and underwater vehicles, etc., as well as personal protective equipment (bioprotective and aerosol masks, etc.), autonomous recirculation plants and other equipment.

A device for sterilization and fine filtering of gas is known according to KI patent 2026751, which implements a method of inactivating microorganisms, according to which, in order to inactivate microorganisms in the air stream, they must first be charged with ions of one or different signs, and then the microorganisms can be retained on an electrostatic filter, where they inactivate over time. To increase the sterilizing effect in the devices, two ionizers of different polarity can be used.

However, in such devices, the inactivation of microorganisms is carried out only after their delay on the electrostatic filter, which is undesirable, since in the process of work there is a constant accumulation of living microorganisms and the risks of their salvo discharge from the installation to the room increase.

In addition, for the inactivation of microorganisms, it is necessary to create high concentrations of ions inside such a device, which is always accompanied by the release of a significant amount of ozone and nitrogen oxides. The ingress of these gases in high concentrations into the air is dangerous for humans and animals. Moreover, the inactivation efficiency of microorganisms depends on the concentration of ions and ozone inside the unit, which limits the reliability of such devices.

A device for inactivation and fine filtering of viruses and microorganisms in the air stream according to the patent KI 2344882, containing a high-voltage power source and arranged sequentially along the stream, means for pre-processing the air stream, formed from oppositely charged conductive filter elements, between which a plate of dielectric highly porous permeable material, two-section inactivation chamber, each section of which is made in the form of coaxially arranged needle corona and cylindrical non-corona electrodes, each of which is electrically connected to a corresponding plate of conductive filtering material, and a precipitator made of oppositely charged plates of highly porous permeable conductive material located parallel to each other, between which are plates of highly porous permeable dielectric material. In this case, at least the first upstream conductive filter element of the pre-treatment means is made in the form of a cylindrical electrode with a base in the form of a plate of a conductive porous permeable material adjacent to a plate of a dielectric highly porous permeable material, and a plate of a conductive highly porous material located at a distance from the free end of the cylindrical electrode, to which the needle electrode is electrically connected with it, married coaxially to the cylindrical electrode and directed by the tip towards the dielectric plate, while the cylindrical and needle electrodes are connected to opposite poles of the power source. The device uses porous permeable electrodes having a volumetric structure, for example, the structure of an open-cell volumetric material (foam metal).

When this device is operating, the necessary concentration of ions of the corresponding signs is created in the corona nodes of the device. In the pretreatment agent, bioaerosols are charged and electric fields of different intensities and gradients are exposed to them. At the tip of the needle corona electrodes, cold plasma is applied to microorganisms.

In this device, rough air is first filtered from large particles. Then microorganisms and viruses are charged by ions of the same sign, then by ions of the opposite sign.

After the pretreatment means, the air stream enters a two-section inactivation chamber equipped with two unipolar or bipolar corona electrodes.

In a two-section inactivation chamber, the bioaerosol is repeatedly recharged by ions, electrical contact with electrodes of different signs and the surface of a polarized dielectric filter material. After passing through the inactivation chamber, the microorganisms and viruses present in the air stream will be in an inactivated state.

After passing through the inactivation chambers, particles that have received a charge sufficient for deposition,

- 1,027,302 lingers in an electrostatic precipitator.

The known device and its method of disinfecting air can eliminate the disadvantages inherent in the above device according to the patent KI 2026751, however, in order to carry out the process of inactivation of microorganisms and viruses, it is necessary to simultaneously fulfill many conditions: at the same time create a high concentration of ions of one or different signs, ozone, tension constant electric fields, polarize the dielectric. It is technically difficult to implement them at the same time and to ensure high efficiency of inactivation of microorganisms in the installation, since each of these factors will affect the processing result. The efficiency of inactivation of microorganisms in such installations will depend on the concentration of ions and ozone inside the installation, the properties of the dielectric material, the electric field strength between the electrodes and other characteristics. This significantly affects the reliability of the device. In addition, for the decomposition of the ozone released inside such installations, it is necessary to use catalysts that require constant monitoring of their performance, which limits the possibility of safe use of such devices in rooms with people and requires additional measures to ensure safe operation.

The main objective of the invention is to increase the efficiency of air disinfection by using the method of rapid electroporation of microorganism cells in constant electric fields to inactivate microorganisms, followed by filtering inactivated microorganisms and aerosol particles on an electrostatic precipitator.

Additional objectives of the present invention are to reduce the emission of ozone and other harmful substances in the process of air disinfection, as well as improving the reliability of the device.

These tasks are solved in the method of disinfection of air, which includes the steps at which create the flow to be disinfected air; act on the specified stream arranged in a constant current electric fields sequentially in the stream, alternating in the direction of the tension vector and created by transverse electrodes permeable to the air stream; and filtering the treated air stream through an electrostatic filter. According to the invention, there are electric field concentrators in the form of protrusions on the surface of the electrodes, the base diameter of which does not exceed 30 μm, and the intensity of each of the alternating constant electric fields between the respective electrodes is selected from the conditions for the electroporation of microorganism cells or their inactivation.

As a result of exposure to a microorganism cell of constant electric fields directed in different directions and their high local intensity near electric field concentrators, a multiple change in the magnitudes and signs of electric potentials occurs on the surface and inside the cell, resulting in changes in the structure of the cell, its electrical and mechanical properties, electroporation of microorganism cells (pore formation in the cell membrane) and the subsequent disintegration (destruction) of their structure.

Preferably, the intensity of each of the alternating constant electric fields between the respective electrodes is at least 2 kV / cm.

In this case, it is desirable to perform the protrusions nanoscale with a base diameter of not more than 100 nm.

Permeable to the air flow electrodes are made in the form of plates of porous conductive materials or of conductive bulk fibrous porous structures.

Preferably, dielectric highly porous plates are installed between the electrodes, on the surface of which nanoscale protrusions can also be made.

The air flow rate is chosen so that the time of exposure of each of the alternating constant electric fields to the particle moving in the flow of air to be disinfected is at least 0.05 seconds.

Preferably, several zones with an increased concentration of ions are additionally arranged along the air stream.

The presence of zones with an increased concentration of ions makes it possible to charge aerosol particles with positive and / or negative ions, which enhances the deposition effect of these particles.

Zones with a high concentration of ions are preferably organized by creating a corona discharge.

Moreover, in part of these zones can create increased concentrations of ions of one sign, and in the remaining zones of another sign.

In addition, zones with a high concentration of ions can have a flow before exposure to the air flow by constant electric fields and / or between the electrodes that create these fields.

The above problems are also solved in a device for disinfecting the air stream, containing electrodes installed in series along the stream in the form of conductive plates permeable to the air stream located across the stream, and a high-voltage power source,

- 2 027302 connected to the electrodes so that the electrodes have alternating polarity. According to the invention, the electrodes have on their surface electric field concentrators in the form of protrusions whose base diameter does not exceed 30 microns.

Concentrators of the electric field on the electrodes provide the appearance of local zones of high tension, while the alternation of these local zones, zones of low tension and zones of lack of tension of constant electric fields with a change in the direction and magnitude of the intensity of these fields leads to rapid electroporation of the microorganism cell and the disintegration of its structure.

Preferably, the protrusions were made nanoscale with a base diameter of not more than 100 nm.

Air-permeable conductive plates may be made of porous electrically conductive materials or of conductive bulk fibrous porous structures.

Between the electrodes can be additionally installed dielectric highly porous plates, which can also have on its surface nanoscale protrusions.

At least one zone with an increased concentration of ions can be formed between the electrodes.

If several zones with an increased concentration of ions are formed between the electrodes, then in some of these zones the ions of increased concentration have one sign, and in the remaining zones - a different sign.

Preferably, zones with a high concentration of ions of one sign alternate with zones of a high concentration of ions of another sign.

In addition, at least one zone with an increased concentration of ions is formed in front of the first electrode along the air stream. If there are several such zones, then it is desirable that the ions in these zones have the same sign.

All of the above zones with a high concentration of ions can be made in the form of coaxially arranged needle-shaped corona and cylindrical non-corona electrodes.

Preferably, at least one zone with a high concentration of ions is bounded at the entrance by a highly porous permeable electrode, the polarity of which coincides with the polarity of the electrode closest to it, while at the output, this zone can also be limited by a highly porous permeable electrode, the polarity of which coincides with the polarity of the electrode closest to it .

The invention is illustrated by drawings.

In FIG. 1 is a schematic cross-sectional view of an apparatus for disinfecting air according to the invention;

in FIG. 2 - the same, but with dielectric highly porous plates between the electrodes; in FIG. 3 is the same as in FIG. 2, but with zones with a high ion concentration formed between the electrodes;

in FIG. 4 is the same as in FIG. 3, but with a zone with an increased concentration of ions formed in front of the first electrode along the air flow;

in FIG. 5 is the same as in FIG. 4, but with a highly porous permeable electrode at the entrance to the zone with an increased concentration of ions formed before the first electrode in the direction of air flow;

in FIG. 6 is the same as in FIG. 5, but with a highly porous permeable electrode at the exit from the zone with a high ion concentration formed before the first electrode in the direction of the air flow;

in FIG. 7 is a diagram of a change in electric field strength near a nanoscale protrusion on an electrode;

in FIG. 8 shows an embodiment of a corona needle electrode, a sectional view.

The implementation of the method according to the invention is illustrated by the example of the operation of the device, schematically depicted in the drawings.

In FIG. 1 shows a simple embodiment of a device that implements the method according to the invention.

This device comprises electrodes 1 arranged in series along the air stream A in the form of conductive plates permeable to the air stream located across the stream, and a high voltage power supply 2 connected to the electrodes 1 so that the electrodes 1 have alternating polarity. The plates from which the electrodes 1 are formed can be made of various materials: permeable foam metals, electrically conductive porous powder materials, bulk fibrous porous structures, etc., it is only necessary to provide an average pore size of no more than 6 mm in the plates of such electrodes. Moreover, on the surface of the electrodes 1, electric field concentrators are made in the form of protrusions 3 (Fig. 7), the base diameter of which does not exceed 30 μm. Preferably, the protrusions 3 are made nanoscale with a base diameter of not more than 100 nm. Nanoscale protrusions 3 on the surface of electrode 1 can be obtained, for example, by powder metallurgy methods. The power source 2 is selected from the condition of creating between adjacent electrodes 1 an electric field of at least 2 kV / cm. In this case, near nanoscale steps 3,027,302 of 3, the diameter of which does not exceed the above value, the electric field strength reaches 100 kV / cm and more, which, as shown by the studies, leads to electrical breakdown of the microbial cell membrane. To create the necessary potential difference between the electrodes and ensure the reliability and stability of the device, the high-voltage power supply must provide stabilization by voltage or current.

When the device is operating, an air stream containing microorganisms and aerosol particles is passed through a system of highly porous electrodes 1 having electric field concentrators in the form of protrusions 3. Near the surface of these electrodes, due to the presence of protrusions 3, local electric fields of high tension exceeding 100 kV are created /cm.

The passage of microorganisms through electric fields repeatedly alternating in direction and magnitude of intensity leads to a multiple change in the magnitudes and signs of electric potentials on the surface and inside the cell, as a result of which changes in the cell structure, its electrical and mechanical properties occur. As a result of repeated depolarization of the cell, pores are formed in its membrane (electroporation) and disintegration (destruction) of its structure. Inactivation of microorganisms by destroying their structure excludes the possibility of their adaptation to such effects, mutations or subsequent recovery (revitalization), i.e. irreversible inactivation of the microorganism is carried out. The number of electrodes 1 with protrusions 3 and the number of changes in the direction of action of constant electric fields is determined based on a given value of the processing speed of the air flow and the parameters of the treated air. The time required to inactivate any type of microorganism can be about 0.5 seconds. Inactivated microorganisms and aerosol particles are retained by an electrostatic filter (not shown). Between the electrodes 1 can be installed dielectric highly porous plate 4 (Fig. 2), preventing electrical breakdown between the electrodes 1 when changing the parameters of the air or gas environment (humidity, dust, temperature, etc.), equalizing the speed of the air flow in the cross section of the device and delaying aerosol particles on its surface.

To improve the efficiency of the device in conditions of high humidity, the device can be additionally equipped with one or more chambers 5 of ionization (Fig. 3), creating zones with a high concentration of ions. The electrical parameters of the ionization chambers are selected so that the emission of ozone and nitrogen oxides does not exceed their normalized values. The ionization chamber 5 can be made in the form of a coaxially arranged needle-shaped corona electrode 6 and a cylindrical non-corona-type electrode 7. In particular, the corona-shaped needle electrode is, for example, a wire 8 (Fig. 8) mounted in a metal tube 9 and protruding from it by an amount sufficient to form an electric corona. In FIG. 3, three ionization chambers 5 are shown, and in the first and last downstream chambers, the corona electrode is connected to one pole of the power supply 2, and in the middle chamber to the other, so that zones with an increased concentration of ions of one sign alternate with zones of an increased concentration of ions of another sign . Nevertheless, if there are several ionization chambers in the device, these chambers can also be located arbitrarily, without the obligatory alternation of zones with an increased concentration of ions of different signs (not shown). For example, for efficient filtering without increasing ozone emission, ionization chambers can generate ions of the same sign.

To create the best working conditions for the device containing the ionization chambers, the power source is configured so that a voltage stabilized in magnitude is supplied to the electrodes 1, and a current stabilized in magnitude is supplied to the electrodes of the ionization chambers.

To increase the intensity of exposure to aerosol particles, to increase the stability of the device at high humidity and dustiness of the air, it is desirable to pre-charge these particles with positive and / or negative ions. To this end, at least one zone with an increased concentration of ions (Fig. 4) is formed in front of the first electrode 1 in the course of the air flow A (Fig. 4) in the form of an ionization chamber 10 similar to any of the ionization chambers 5 located between the electrodes 1.

The ionization chamber 10 can be limited at the input by a highly porous permeable electrode 11 (Fig. 5), the polarity of which coincides with the polarity of the electrode 1 nearest to it. At the exit from the ionization chamber 10, a highly porous permeable electrode 12 can also be located (Fig. 6), polarity which coincides with the polarity of the electrode 1 nearest to it.

The limitation of the ionization chamber 10 at the inlet and / or outlet with highly porous permeable electrodes 11 and / or 12 helps to improve the conditions for charging the aerosols inside the chamber and simplifies the multiple recharging of the bioaerosol when passing through the installation.

To increase the amount of pre-charge of aerosol particles, there can be several (not shown) positive and / or negative ions of the ionization chambers 10 located in front of the first electrode along the air stream.

Monitoring the effectiveness of air disinfection can be carried out by monitoring the electrical parameters of the device elements (currents, voltages, etc.).

- 4 027302

As a result of the use of the invention, a quick, effective, reliable air purification from any types of microorganisms and viruses, as well as from aerosol particles with a size of from 0.08 microns, is provided. At the same time, increased hygiene safety is also ensured due to the inactivation of microorganisms to the filtration stage, as well as due to the absence of dangerous concentrations of ozone and other harmful substances.

If necessary, to purify the air from harmful and unpleasant smelling substances, one or more plates of highly porous electrodes or plates of a highly porous dielectric may have an adsorption-catalytic coating.

If it is necessary to increase the efficiency of filtering aerosol particles between the electrodes of the device, an additional filter material or a high-performance filter can be installed.

Claims (25)

CLAIM 1. A method of disinfecting air, comprising the steps of creating a stream of air to be disinfected; act on the specified stream arranged in a constant current electric fields sequentially in the stream, alternating in the direction of the tension vector and created by transverse electrodes permeable to the air stream; and filtering the treated air flow by means of an electrostatic filter, characterized in that on the surface of the electrodes there are electric field concentrators in the form of protrusions, the base diameter of which does not exceed 30 μm, and the intensity of each of the alternating constant electric fields between the respective electrodes is selected from the conditions for the electroporation of microorganism cells or their inactivation. 2. The method according to claim 1, characterized in that the intensity of each of the alternating constant electric fields between the respective electrodes is at least 2 kV / cm. 3. The method according to claim 1, characterized in that the protrusions are made nanoscale with a base diameter of not more than 100 nm. 4. The method according to claim 1, characterized in that the electrodes permeable to the air flow are made in the form of plates of porous conductive materials or of conductive bulk fibrous porous structures. 5. The method according to claim 1, characterized in that the air-permeable dielectric highly porous plates are installed between the electrodes. 6. The method according to claim 5, characterized in that on the surface of the dielectric highly porous plates perform nanoscale protrusions. 7. The method according to claim 1, characterized in that the air flow rate is selected so that the exposure time of each of the alternating constant electric fields to the particle moving in the air to be disinfected is at least 0.05 s. 8. The method according to claim 1, characterized in that in the course of the air flow additionally organize several zones with a high concentration of ions. 9. The method according to claim 8, characterized in that the zone with a high concentration of ions is organized by creating a corona discharge. 10. The method according to claim 8, characterized in that in part of these zones create an increased concentration of ions of one sign, and in the remaining zones of another sign. 11. The method according to claim 8, characterized in that zones with a high concentration of ions are arranged in a stream before exposure to the air stream by constant electric fields and / or between these fields. 12. The device for disinfecting the air flow by the method according to claim 1, containing electrodes arranged in series along the flow in the form of conductive plates permeable to the air flow, located across the flow, and a high-voltage power source connected to the electrodes so that the electrodes have alternating polarity, different the fact that the electrodes have on their surface electric field concentrators in the form of protrusions, the diameter of the base of which does not exceed 30 microns. 13. The device according to p. 12, characterized in that the protrusions are made nanoscale with a base diameter of not more than 100 nm. 14. The device according to p. 12, characterized in that permeable to the air flow conductive plates are made of porous conductive materials or of conductive bulk fibrous porous structures. 15. The device according to p. 12, characterized in that between the electrodes are additionally installed air-permeable dielectric highly porous plates. 16. The device according to clause 15, wherein the highly porous dielectric plates have nanoscale protrusions on their surface. 17. The device according to p. 12, characterized in that between the electrodes formed at least - 5 027302 one zone with a high concentration of ions. 18. The device according to 17, characterized in that between the electrodes are formed several zones with a high concentration of ions, moreover, in some of these zones, ions of high concentration have one sign, and in the remaining zones - a different sign. 19. The device according to p. 18, characterized in that the zone with a high concentration of ions of one sign alternate with zones of a high concentration of ions of another sign. 20. Device according to any one of paragraphs.12 or 17, characterized in that at least one zone with an increased concentration of ions is formed in front of the first electrode along the air stream. 21. The device according to claim 20, characterized in that several zones with an increased concentration of ions of the same sign are formed in front of the first electrode along the air stream. 22. The device according to 17, characterized in that the zone with a high concentration of ions is made in the form of coaxially located needle-shaped corona and cylindrical non-corona electrodes. 23. The device according to claim 20, characterized in that the zone with a high concentration of ions is made in the form of coaxially arranged needle-shaped corona and cylindrical non-corona electrodes. 24. Device according to any one of paragraphs.22 or 23, characterized in that at least one zone with a high concentration of ions is limited at the input by a highly porous permeable electrode, the polarity of which coincides with the polarity of the electrode closest to it. 25. The device according to p. 24, characterized in that at least one zone with a high concentration of ions is limited at the output by a highly porous permeable electrode, the polarity of which coincides with the polarity of the electrode closest to it.