RU2480244C2 - Air cleaner - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to air cleaning and sterilisation, particularly, to cleaning are of viruses, bacteria, vapors and aerosols of organic and inorganic compounds including dioxins, benzpyrenes, furans, carbon dioxide, ammonium and ozone. Proposed air cleaner comprises mechanical filter, UV-radiation source, metallic, electrostatic and photo catalytic filters, electrostatic filter settler from dielectric material, and adsorption-catalytic filter. In compliance with this invention it comprises sorption filter and electrostatic filter settler. Electrostatic and photo catalytic filters are integrated in one-piece combined multilayer element, every said layer being made of high-porosity material with photo catalytic nanostructured coating applied on its surface. Note here that said electrostatic and photo catalytic filters with settler arranged there between are made from foam metal while UV-source is arranged immediately nearby electrostatic filter.

EFFECT: higher efficiency.

10 cl, 2 dwg

Description

The invention relates to the field of purification and sterilization of air in domestic, household and industrial premises, namely, devices for sterilization, deodorization and purification of air from viruses, bacteria, vapors and aerosols of organic and inorganic compounds, including phenol, ketones, aldehydes, carbon monoxide , ammonia and ozone.

The prior art device for sterilization and fine filtering of gas, including a power source, a filter installed across the stream, a cleaning filter, an ionizer with corona and non-corona electrodes, a precipitator of conductive elements in the form of plates and a fine filter, while the coarse filter is made of highly porous electret material and is equipped with oppositely charged filter elements made of highly porous material placed on both sides across the flow, the second current-conducting conductor the filter element is electrically connected to one of the electrodes of the ionizer, the other electrode of which is provided with a baffle mounted across the flow and made of conductive filter material, and the precipitator is equipped with a dielectric filter element of highly porous electret material placed between the conductive elements (see RF patent for invention No. 2026751. “Device for sterilization and fine filtering of gas.” Submission date 05/13/1992, published on 01/20/1995).

In addition, it is known a device for cleaning gas emissions, in which precipitation electrodes with a catalytic coating are made with the possibility of direct transmission of electric current or with heat-generating elements mounted in them to heat the catalytic coating to the temperature necessary for the catalytic treatment of the gas stream (see RF patent for invention No. 2286201. “A method for cleaning gas emissions and a device for its implementation.” Submission date 01/20/2004, the date of publication of the application 06/27/2005

A known device for air purification related to reactors designed to clean aerosol particles that are carried in a fluid stream passing through the reactor. The reactor includes a plasma chamber configured to receive a fluid stream and used to treat particles with cold plasma containing a sufficiently high concentration of active particles capable of purifying at least some particles passing through the chamber. The catalyst located in the plasma chamber downstream serves to increase the conversion of active particles that are contained in the fluid stream before the stream exits the reactor. In addition, the reactor contains a catalytic electrode on which a catalytic material is deposited. During the operation of the reactor, a potential may be applied to the electrode to attract charged particles. In some embodiments of the reactor, the catalytic electrode includes a metal frame that serves as a conductive electrode and supported on a catalytic material such as manganese dioxide (see US Pat. No. 7,771,672 B2. "AIR PURIFICATION DEVICE.") 04/18/2006, publication date 06/21/2007).

A device for electrostatic cleaning of aerosols, consisting of a volume generator (1) of a chaotic electrostatic field (E), locally amplified to expose a fluid (U) loaded with batches of aerosol (P, p), to the effect of an electrostatic field (E), highly variable in amplitude and orientation locally. The generator (1) includes: an inducible electrostatic module (2), consisting of a porous dielectric material (md), two porous electrodes with electrostatic induction (4, 5), an electric current source (6) and a device for increasing the pressure of the fluid. The electrostatic module (2) consists of a system (Rxyz) of three-dimensional grids having at least locally three-dimensional periodicity (or pseudo-periodicity) in at least three directions. Each grid of the system consists of a unit cell convex outward and concave inward, recessed flush in its center, for inclusion of a compact elementary empty cellular volume (VI), i.e. with transverse measurements (dx1, dy1, dz1) of the same order of magnitude in these three directions. Mostly it consists of many physically and electrically interconnected ribs in the form of a dodecahedral array. The generator (1) is applicable for air filtration and in chemistry (see US Patent No. 6,805,732 B1. “ELECTROSTATIC TREATMENT OF AEROSOLS DEVICE AND METHOD FOR PRODUCING SAME”. PCT application submission date 23.11.2000, PCT application publication date 31.05. 2001).

In addition, an electrostatic filter is known, equipped with an improved dielectric constituting a dielectric lining formed of high-porosity non-woven fibers having pores, wherein the ratio of pore area of the filter membrane to the total area of the filter element is 97%. The dielectric lining is sandwiched between a pair of porous electrodes. The fibers forming the lining have a maximum transverse thickness that is less than 100 microns, and the ratio of length to maximum thickness is> 10. The pores are preferably statistically essentially the same calibrated and extend in three dimensions. In various preferred embodiments of the device, the ratio of the pore area of the filter baffle to the total area of the filter element of the dielectric pad exceeds 99%. The lining preferably has a tortuosity of at least 2. The maximum transverse width of the fibers is preferably in the range of 0.1 to 50 microns. In many embodiments, the fibers that form the dielectric lining are made from either polyester or polypropylene. In some embodiments, the cross-section of the fibers will have at least one (and preferably two or more) separate region of a small transverse radius of the curve along its perimeter (see US patent No. 7,279,028 B2. ELECTROSTATIC FILTER. Date of filing 18.04 .2006, publication date 06/21/2007).

The closest technical solution to the claimed invention is an air purification system "TION", which uses a set of filters: a preliminary filter, which serves to mechanically clean the air from dust; an electrostatic filter consisting of a sedimentation and charging sections intended to charge particles, while on a precipitation section made of dielectric material, charged particles are deposited and air is cleaned of all mechanical impurities, and polypropylene obtained by extrusion is used as the material for the precipitation section; a photocatalytic filter that destroys viruses, bacteria and purifies the air of molecular organic substances that decompose to carbon dioxide and water; adsorption-catalytic filter that purifies the air of molecular compounds. The charging section and the photocatalytic filter are made in the form of metal plates connected to a power source, and the plates of the charging section are grounded. In this system, the air purification process is carried out in one pass (see http://www.tion.info/technology, posted on the Internet in 2010).

The disadvantages of this device are due to the bulkiness of the design, in which the internal space is conditionally divided into separate, remote sections, each of which undergoes a separate process, which leads to a decrease in the general (synergistic) effect of air purification, as well as the degree of air purification.

The technical result, to which the claimed invention is directed, is to create a compact design with increased efficiency of sterilization and filtration of air or gas and reducing the level of ozone formation.

The claimed result is achieved in that the air purification device comprising a mechanical filter, a UV radiation source, metal electrostatic and photocatalytic filters, an electrostatic precipitator of a dielectric material, an adsorption-catalytic filter according to the invention further comprises a sorption filter, an electrostatic precipitator, an electrostatic and Photocatalytic filters are assembled together in a single combined multilayer element, each layer of which made from a highly porous material deposited on the surface of photocatalytic nano-structured coating, with electrostatic filters and photocatalytic sandwiching precipitator made from metal foam, and the source of UV radiation is located in the immediate vicinity of the electrostatic filter.

As a mechanical filter, for example, an HEPA filter is used.

The adsorption-catalytic filter is made of a material based on alkali metal oxides or manganese oxide.

As a foam metal for the manufacture of electrostatic and photocatalytic filters, for example, nickel, or copper, or stainless steel, or titanium is used, and the precipitant is made of polyurethane foam.

The sorption filter is made of activated carbon or zeolites.

As the photocatalytic coating, a nanostructured photocatalytic coating based on titanium dioxide, including modified with platinum or palladium or gold, is applied, for example, applied in the form of a suspension, or by spraying, or in another way.

The electrostatic and photocatalytic filters are made of highly permeable materials having both the same pore size and different, and in this case, the material of the photocatalytic filter has a smaller pore size.

To enhance the process efficiency and depending on the volume of air intended for air purification, the device can be equipped with additional sources of UV radiation and multi-layer structures.

Perhaps a radial arrangement of structural elements equidistant from the central axis, which is used as a source of UV radiation.

The combination of the precipitator of the electrostatic filter, electrostatic and photocatalytic filters into a single combined multilayer element, as well as the location in the immediate vicinity of it of a UV radiation source, allows the entire volume of air to be treated to be cleaned in one step, while various physical, mechanical and chemical processes occur , including directional electrodeposition of aerosols and contaminants, ultraviolet radiation, enhancing photocatalytic oxidation -reduction reactions on the catalyst surface, exposure to ozone and radicals generated electric field, non-uniform at the micro level. The simultaneous occurrence of heterogeneous processes in a compact space has a significant synergistic and promoting mutual influence on each other.

In addition, the presence in the claimed design of a combined multilayer element, each layer of which is made of highly porous material with a photocatalytic coating deposited on its surface, allows several physicochemical processes to be carried out simultaneously, including the creation of an electric field, the generation of ozone and free radicals, and catalytic reactions on the surface. The multilayer element has high permeability for both cleaned air and UV radiation.

Technical solutions that coincide with the totality of the essential features of the claimed invention have not been identified, which allows us to conclude that the claimed invention meets such a patentability condition as “novelty”.

The claimed essential features that predetermine the receipt of the specified technical result, do not explicitly follow from the prior art, which allows us to conclude that the claimed invention meets such a patentability condition as "inventive step".

The patentability condition "industrial applicability" is confirmed by the example of a specific implementation.

The invention is illustrated by drawings, where

Figure 1 - General diagram of a device for air purification;

Figure 2 - General diagram of a device for air purification with a radial arrangement of structural elements.

The air purification device consists of a housing 1 with an inlet in which a coarse mechanical filter 2, at least one UV-radiation source 3.1, at least one electrostatic filter, for example 4.1, a catalytic filter 5 are installed across the air flow , mainly the main (alkaline) type, and a sorption filter 6, made, for example, of activated carbon or zeolites.

The device can be additionally equipped with at least one other source of UV radiation 3.2 and an electrostatic filter 4.2.

Coarse mechanical filter 2, in particular the HEPA filter, is made of a multilayer filter material, including non-woven cloth, fabric, paper, etc., and is intended mainly for cleaning the air flow from mechanical impurities, dust and inclusions including animal hair, fluff. The UV radiation source 3.1 is either an ultraviolet lamp or a matrix consisting of LEDs installed along the electrostatic filter 4.1, which is a multilayer structure consisting of two electrostatic electrodes 4.1.1 and 4.1.2, between which a precipitator of the electrostatic electrode 4.1 is placed. 1, made in the form of a dielectric plate 4.1.3, while one of the electrodes, for example 4.1.1, is connected to the negative pole of the power source 7 and can be grounded, and the other electrode 4.1.2 is connected to respectively to the positive pole. The polarity of the electrodes, if necessary, can be reversed in order to create ion wind flows. Electrodes 4.1.1 and 4.1.2 clean the air of viruses, bacteria, molecular organic substances, destroying them to carbon dioxide and water. The electrodes 4.1.1 and 4.1.2 are made of highly porous foam metal, for example nickel (Ni), the surface of which is coated with a photocatalytic nanostructured coating based on titanium dioxide (TiO ₂ ), while the application of a catalytic nanostructured coating on the surface of the second electrode is optional. The foam metal used for the manufacture of each of the electrodes 4.1.1 and 4.1.2 can be made with the same pore size or different, and in this case the material of the photocatalytic filter has a smaller pore size.

The dielectric plate 4.1.3 is made of a highly porous permeable material, for example polyurethane foam, on the surface of which a nanostructured photocatalytic coating based on titanium dioxide (TiO ₂ ) is also applied.

Behind electrodes 4.1.1 (4.1.2), a sorption-catalytic element of a predominantly basic type is installed and is intended for the disposal of chemical intermediates, including nitrogen oxides, ozone, hydroxyl ions, etc., formed during plasma and electrical processes. In the housing 1 there is a sorption filter 6, which serves to purify air from harmful molecular compounds and made of sorption material, for example, activated carbon or zeolites - molecular sieves.

If an additional electrostatic electrode 4.1.2 is placed in the casing, catalytic layers of a different composition, for example, hopcalites (MnO ₂ -CuO-AgO), perovskite and spinel structures (LaAgMnO), and others are used as coatings for electrodes 4.2.1 and 4.2.2 metal oxide compositions, platinum, palladium and other noble metals that contribute to the decomposition of ozone, or use sorption layers made, for example, of activated carbon.

Perhaps a radial arrangement of structural elements equidistant from the central axis, which is used as a source of UV radiation.

The implementation of the device is illustrated by examples of specific performance.

Example 1

The air entering the device body 1 (Fig. 1) passes through a coarse filter 2 at the first stage, which mechanically traps coarse dust, fluff, pet hair, and all kinds of inclusions. This filter requires periodic cleaning or replacement depending on operating conditions.

Next, the air stream is subjected to ultraviolet radiation, carried out using at least one UV source 3.1, located near the photocatalytic electrode 4.1.1. Under UV irradiation, water vapor dissociates with the formation of OH ^- and H ⁺ ions, as well as the decomposition of organic substances at the molecular level. Ultraviolet disinfection destroys the causative agents of such infectious diseases as typhoid, cholera, viral hepatitis, poliomyelitis and others. Ultraviolet disinfection occurs due to photochemical reactions inside microorganisms. In contrast to oxidative reactions, in particular ozonation, in the case of an overdose of UV radiation, there are no negative effects.

The next step is the purification of air from fine aerosols, which occurs on the electrostatic electrode and, first of all, on the first photocatalytic electrode 4.1.1, which generates active chemical compounds that react in air. Thanks to the manufacture of an electrode from highly porous foam metal, its active surface increases. In addition, due to the presence of a photocatalytic coating with titanium dioxide on the surface of the electrode 4.1.1, when a high voltage (+ 4-7 kV) is applied, an inhomogeneous electric field is created that ionizes the air and contributes to a more intense redox reaction. In addition, the coating acts as a corona electrode. Titanium dioxide refers to semiconductors in which electrons can either freely move along the crystal lattice, or, participating in a chemical reaction, be in a bound state.

When the photocatalytic electrode 4.1.1 is located near the UV radiation source, when light is absorbed, the transition of electrons from the bound state to the free state with the formation of so-called “holes” is possible. Both those electrons and “holes” that do not disappear inside the particles of a titanium dioxide nanopowder, but exit onto the surface of the electrode, are captured by it.

As a result of reactions in the area adjacent to the electrode 4.1.1, a nonequilibrium plasma is formed, consisting of free electrons and ionized atoms of nitrogen (N ⁺ ) and oxygen (O ^- ), which under the influence of an electric field move in the direction of the electrode 4.1.1, creating a current, and oxidize any organic matter to H ₂ O and CO ₂ , and the catalyst is not consumed. At the same time, atomic oxygen (О ^- ) and ozone (О ₃ ) are formed in a significant amount, as well as OH ^- and Н ⁺ water electrolysis products, which are strong oxidizing agents. Ionized atoms are deposited on aerosol particles in the air and charge them. No harmful substances are emitted from the photocatalytic electrode, since ozone, atomic oxygen and radicals are deactivated during the ongoing processes.

The location of the source of UV radiation 3.1 near the electrostatic electrode 4.1.1 has a synergistic effect, enhancing and accelerating the processes taking place in this area.

Part of the charged particles settles on the surface of the grounded electrode 4.1.1, and the remaining part falls on the dielectric plate 4.1.3 and settles on it. Moreover, large particles are trapped on the surface of the dielectric plate due to inertial motion, medium particles moving along the air flow lines and adhering to the surface tangentially settle due to interception, and small particles that jump out of the stream during chaotic motion settle due to Brownian diffusion.

It should be noted that the deposition of charged aerosol particles, as well as redox processes proceed more efficiently on the catalytic surface of the dielectric plate coated with titanium oxide 4.1.3. This is due, inter alia, to the sticking together of charged particles, their directed deposition on a catalytic coating. The aerosol retention efficiency corresponds to class H14 and is 99.995%.

In addition, bacteria, viruses, mold spores are inactivated due to ozone and atomic oxygen in the air stream, which oxidize the cells of microorganisms, while the destruction efficiency of these cells is effective for all types of microorganisms, since the mechanism of the process is chemical.

After deposition on the dielectric plate 4.1.3, the molecular compounds remaining in the air stream, as well as the generated ozone and atomic oxygen, pass together with the aerosol residues through a 4.1 photocatalytic filter, with the help of which the air is purified on the titanium dioxide nanoparticles from molecular compounds, unpleasant odors and harmful residues microorganisms. The mechanism of the processes is similar to that which occurs on the electrode 4.1.1, however, it occurs much more intensively and efficiently due to the ozone and atomic oxygen received from this electrode. As a result of this, the destruction of organic substances is several times higher than that of conventional photocatalytic air purifiers.

The final stages, which allow purifying the air of all contaminants, take place on the main type adsorption-catalytic filter, which carries out the capture of molecular compounds, utilizes the chemical intermediates of plasma and electrical phenomena. In addition, this filter delays volley emissions of harmful substances of high concentration.

The principle of operation of this filter is adsorption, in which the deposition of molecular compounds occurs in the pores of the sorbent. In the claimed invention, a material based on manganese dioxide or alkali metal oxides providing a higher degree of air purification is used as a sorbent.

It should be noted that the flow of air after the photocatalytic electrode 4.1.2 contains peroxides that contribute not only to the capture of molecular contaminants, but also to the self-cleaning of the filter. This occurs due to the introduction of peroxides in reactions with molecules of organic compounds deposited on the sorbent. As a result, the service life of the filter and its efficiency are significantly increased.

The final air purification takes place in a sorption filter, for which activated carbon or zeolites are used, for example.

Depending on the volume of air intended for cleaning, the device can additionally be equipped with UV radiation sources (3.2) and electrostatic electrodes (4.1.2).

Example 2

A device for air purification with a radial arrangement of structural elements (figure 2), equidistant from the Central axis, which is used as a source of UV radiation, works as follows. Air enters the housing (not shown), with all the processes described in example 1 occur in a limited space at the same time.

The advantages of the claimed invention are the ability to simultaneously conduct disinfection and purification of air from all types of pollution, and the process is carried out in one pass. In addition, the device destroys and destroys all types of viruses, bacteria and molds, and sterilization and cleaning products do not accumulate filters.

The claimed technical solution purifies the air around the clock in the presence of people and is not a source of ultraviolet radiation, ozone, atomic oxygen, etc. In addition, this technical solution has a compact design with increased efficiency of sterilization and filtration of air or gas and reducing the level of ozone formation.

Claims (10)

1. An air purification device comprising a mechanical filter, a UV irradiation source, metal electrostatic and photocatalytic filters, an electrostatic precipitator of a dielectric material, an adsorption-catalytic filter, characterized in that it further comprises a sorption filter, and an electrostatic precipitator, electrostatic and photocatalytic filters are assembled together in a single combined multilayer element, each layer of which is made of highly porous material la-applied to the surface of the photocatalytic nanostructured coatings, wherein the electrostatic filter and the photocatalyst, between which a precipitator made from metal foam, and the source of UV radiation is located in the immediate vicinity of the electrostatic filter. 2. The air purification device according to claim 1, characterized in that, for example, a HEPA filter is used as a mechanical filter. 3. The air purification device according to claim 1, characterized in that the adsorption-catalytic filter is made of a material based on manganese oxide or alkali metal oxides. 4. The air purification device according to claim 1, characterized in that for the manufacture of electrostatic and photocatalytic filters from foam metal, for example, nickel, or copper, or stainless steel, or titanium is used. 5. The air purification device according to claim 1, characterized in that the precipitant is made of polyurethane foam. 6. The air purification device according to claim 1, characterized in that the sorption filter is made of activated carbon or zeolites. 7. The air purification device according to claim 1, characterized in that as the photocatalytic coating, a nanostructured photocatalytic coating based on titanium dioxide, including that modified with platinum or palladium or gold, is used. 8. The air purification device according to claim 1, characterized in that the electrostatic and photocatalytic filters are made of highly permeable materials having both the same pore size and different, and in this case, the material of the photocatalytic filter has a smaller pore size. 9. The air purification device according to claim 1, characterized in that it is additionally equipped with UV radiation sources and multilayer elements. 10. The air purification device according to claim 1, characterized in that it is made with a radial arrangement of structural elements equidistant from the central axis, which is used as a source of UV radiation.