RU201277U1 - ELECTROSTATIC FILTER - Google Patents

Abstract

The utility model relates to the technique of air conditioning and air purification in domestic and industrial conditions, namely, to electrostatic filters for air purification, including a housing containing an inlet window, an outlet window, a filter and a fan, an irradiation chamber is formed in the housing, which has an electrostatic charging unit , block of deposition of charged particles. The device can be effectively used to clean the air from solid particles, spores, microorganisms, atoms, molecules and ions of many harmful substances in ventilation systems and rooms. According to the utility model, the inner surface of the housing and the irradiation chamber is covered with a material that reflects light radiation, and inside the housing, in front of the output absorbing duct, there are an emitter and a collecting electrode connected to ground via a voltage source, while the collecting electrode, emitter and absorbing airway labyrinth screens are made of material or coated with a material chemically inert with respect to atmospheric air substances and having an electron work function less than or equal to 3.10 eV for the material of the emission electrode and more than 6 eV for the coating of collecting electrodes and the inner surface of the housing. The emitter can be made in the form of needle, wire, powder and other types of structures with a minimum radius of curvature of the surface, which can significantly reduce the effective work function of the electron. The collecting electrode has holes for air passage. Since the collecting electrode is grounded, the device enriches the air passing through it with negative air ions, due to the fact that the Earth's surface is negatively charged. The achieved technical result is an increase in the efficiency of purification, disinfection and improvement of the quality of treated air by neutralizing harmful positively charged light and heavy air ions and purifying it from dust and spores.

Description

The utility model relates to the technique of air conditioning and air purification in domestic and industrial conditions, namely, to electrostatic filters for air purification, including a housing containing an inlet window, an outlet window, a filter and a fan, an irradiation chamber is formed in the housing, which has an electrostatic charging unit , block of deposition of charged particles. The device can be effectively used to clean the air from solid particles, spores, microorganisms, atoms, molecules and ions of many harmful substances in ventilation systems and rooms.

State of the art.

An electrostatic filter for air purification is known from the prior art, which includes a housing containing an inlet window, an outlet window, a filter and a fan, an irradiation chamber is formed in the housing, which has an electrostatic charging unit, a charged particle deposition unit. (see patent RU No. 125894, published 03/20/2013). It describes an air purification device containing an electrostatic charging unit with corona-forming plate-type grounded electrodes installed parallel to the air flow and a charged particle deposition unit, which is a housing in the cavity of which a filter element is installed, made of a porous nonwoven material consisting of micron and submicron synthetic fibers with a dipole moment. This device is the closest in technical essence to the claimed invention and is taken as a prototype to the proposed invention.

The disadvantage of the above-described device, like all similar ones, is the creation of a corona discharge field for acquiring a charge of particles suspended in the air, which is also a consequence of the ozonization of the purified air and the secondary ionization of oxygen in the air. Ozonation and secondary ionization of air oxygen create harmful and uncomfortable conditions for humans and animals in the treated room.

That is, the problem the solution to which the present utility model is directed is to improve the quality of the treated air due to the complete absence of ozonation of the air, high-quality air purification from particulate matter, spores, microorganisms, atoms, molecules and ions of many harmful substances, as well as disinfection of air in ventilation systems and rooms.

Disclosure of the utility model.

The present utility model mainly aims to propose an electrostatic filter for air purification, which includes a housing containing an inlet window, an outlet window, a filter and a fan, an irradiation chamber is formed in the housing, which has an electrostatic charging unit, a charged particle deposition unit that allows , at least one of the above disadvantages, namely, to provide an increase in the efficiency of cleaning, disinfection and improvement of the quality of the treated air by neutralizing harmful positively charged light and heavy air ions and purifying it from dust and spores, which is the set technical task. That is, the task is to prevent ozonation of oxygen in the air and to expand the scope of the electrostatic filter through the use of specially selected materials for the electrodes of the electrostatic charging unit and the electrodes of the particle deposition unit, as well as the use of a fan for forced passage of air through the electrostatic filter.

To achieve this goal, a light source and airway absorption labyrinths are located inside the housing, while the inner surface of the irradiation chamber is covered with a material that reflects light radiation, and the electrodes of the electrostatic charging unit and the electrodes of the charged particle deposition unit are made of materials that are chemically inert with respect to substances outside and having an electron work function _(AV) of less than or equal to 3.10 eV for the coating material electrostatic charging unit electrodes, and the coating of the electrodes of charged particle precipitation unit and the inner surface of the irradiation chamber AB more than 6 eV.

In general, UV absorbing materials such as titanium carbide, hafnium carbide, lanthanum hexaboride, etc. are used as the coating material for the inner surface of the absorption airway labyrinths. (see table 1.).

Thanks to such an advantageous characteristic, it becomes possible to use the external photoelectric effect for the emission of electrons from the emitter and for charging and recharging solid particles, spores, microorganisms, atoms, molecules and ions of many harmful substances and use a low voltage on the electrostatic filter electrodes, which will not lead to the formation of ozone ... and multiple reflection of light radiation from the inner surfaces of the camera increases the efficiency of the external photoelectric effect.

This improves the efficiency of cleaning, disinfection and improving the quality of the treated air by neutralizing harmful positively charged light and heavy air ions and cleansing it of dust and spores. This is achieved, in particular, due to the fact that in the installation for increasing the emission of electrons from the negative electrode, in addition to the potential difference supplied to the electrodes, an external photoelectric effect is also used and chemically inert materials with a minimum work function of the electron are selected, which allows a significant decrease in the operating voltage at the electrodes electrostatic dust collector.

Ionization is achieved due to the emission of electrons under the action of the photoelectric effect and the supply of voltage to the electrodes, a prerequisite for which are electrodes with specially selected characteristics, which are illuminated by a special lamp with a maximum radiation in the range from 400 nm to 420 nm, which corresponds to a quantum energy of 2.95-3 , 10 eV, falling on the violet part of the spectrum of visible light. In particular, various LED lamps can be used as the light source. Ionized particles, molecules, atoms and ions are charged and recharged from the emission electrode, deposited and discharged on the positively charged electrode. It is also possible to use ozone-free ultraviolet lamps, made with a maximum of short-wave ultraviolet radiation at 253.7 nm, which corresponds to a light quantum energy of 4.9 eV, and equipped with a flask consisting of glass filtering out a spectral line at 185 nm, that is, quanta during interaction with which ozone is formed.

An increase in the efficiency of disinfection and an improvement in the quality of the treated air also occurs due to the neutralization of harmful, positively charged air ions and the fact that microorganisms belong to cumulative photobiological receivers, and, therefore, the bactericidal efficiency of air disinfection is proportional to the exposure time and, ultimately, is determined by the radiation dose. In this utility model, this is achieved by multiple reflections of ultraviolet radiation from the inner surfaces of the camera.

The emitter can be made in the form of needle, wire, powder and other types of structures with a minimum radius of curvature of the surface, which can significantly reduce the work function of the electron.

The collecting electrode has holes for air passage.

Electron work function in vacuo in the photoelectric effect is calculated from the formulas

кинетическая энергия электрона.where hν is the energy of the quantum,

kinetic energy of an electron.

For normal atmospheric conditions, hν can be less by the electron affinity of oxygen, carbon dioxide and water molecules, that is, by 0.44 eV, 0.51 eV, 0.8 eV, respectively. For example, hafnium carbide can already ionize at 1.6 eV in the affinity of emission electrons with oxygen molecules, forming negative air ions of oxygen in the air.

The difference between a removable electrostatic filter and analogs is that the emission of electrons from the negative electrode is carried out mainly due to the photoelectric effect and the design of the emitter and collecting electrode of the filter. The emitter is made of a material or its surface is covered with a material in which the value of the electron work function is less than or equal to 3.10 eV, for example, titanium coated with titanium carbide, and the deposition positive electrodes are made of a material or their surface is covered with a material in which the value of the electron work function significantly more than 6 eV, in particular, aluminum coated with AL ₂ O ₃ A _B = 7.35 eV has good characteristics. At these values, Al ₂ O ₃ does not absorb, but reflects the maximum radiation with a photon energy of 4.9 eV, and there is no secondary electron emission on it.

Emission electrodes must be chemically inert with respect to atmospheric substances. The use of such materials in the manufacture of electrodes makes it possible to use the photoelectric effect and thereby significantly reduce the voltage of the direct current source used for ionization and filtration of air, as well as reduce or eliminate air ozonation and its secondary ionization.

The materials shown in Table 1 are suitable for coating the emitter.

Table 1.

Material A _B (eV) Hafnium carbide (HfC) 2.04 Scandium diboride (ScB ₂ ) 2.30 - 2.90 Niobium carbide (NbC) 2.24 Tantalum Carbide (TaC) 3.03-3.10 Titanium Carbide (TiC) 2.35-3.1 (Powdered) 2.35-3.10 Titanium oxide (TiO) 2.96-3.10 Tungsten diboride (WB ₂ ) 2.62 Zirconium carbide (ZrC) (powder) 2.20 -3.05 Tungsten carbide (W ₂ C) 2.60 Cerium Hexaboride (CeB ₆ ) 2.59 Scandium hexaboride (ScB ₆ ) 2.96 Gadolinium Hexaboride (GdB ₆ ) 2.05 Yttrium hexaboride (YB ₆ ) 2.22 Lanthanum Hexaboride (LaB ₆ ) 2.68 Strontium hexaboride (SrB ₆ ) 2.96

There is a variant of the utility model, in which the light source is configured to create a maximum radiation in the range from 400 nm to 420 nm.

Thanks to this advantageous characteristic, it becomes possible to maximize the cleaning performance of the device.

There is a variant of the utility model, in which the light source is made in the form of an ozone-free ultraviolet lamp, made with a maximum of short-wave ultraviolet radiation at 253.7 nm, which corresponds to a light quantum energy of 4.9 eV, and equipped with a bulb made of glass that filters out the spectral line at 185 nm, that is, quanta when interacting with which ozone is formed

Thanks to this advantageous characteristic, it becomes possible to exclude air ozonation.

There is an embodiment of the utility model in which the electrostatic charging unit is connected to a voltage source through a voltage regulator.

Thanks to this advantageous characteristic, it becomes possible to regulate the voltage.

There is a variant of the utility model, in which the inner surface of the irradiation chamber and the surface of the collecting electrode are coated with aluminum.

Thanks to this advantageous characteristic, it becomes possible to use a cheap and affordable material with the required characteristics. Aluminum has a good ability to reflect ultraviolet radiation, due to the fact that Al ₂ O ₃ A _B = 7.35 eV, and the maximum possible energy of quanta in the irradiation chamber is 6.3 eV.

There is another embodiment of the utility model, in which a material having an electron work function of less than or equal to 3.1 eV is selected as the coating material for the emission electrode.

Thanks to such an advantageous characteristic, an alternative opportunity appears to maximize the use of the energy of quanta of visible light and ultraviolet radiation for ionization, which decreases in the process of reflection and partial absorption. For example, for hafnium carbide from 4.9 eV to 2.04 eV, which corresponds to the orange part of the visible light spectrum.

In addition, there is such a variant of the utility model, in which one of the following materials is selected as the coating material for the electrodes of the electrostatic charging unit: scandium diboride, niobium carbide, titanium carbide, titanium oxide, tungsten diboride, hafnium carbide, cerium hexaboride, scandium hexaboride , gadolinium hexaboride, yttrium hexaboride, lanthanum hexaboride, strontium hexaboride.

Thanks to this advantageous characteristic, there is an alternative opportunity to use materials that are chemically inert, non-toxic, with proven characteristics, some of which are relatively cheap, for example, titanium carbide, cerium hexaboride, yttrium hexaboride and tungsten diboride.

There is also such a variant of the utility model, in which titanium or another resistant metal is chosen as the material of the electrodes of the electrostatic charging unit, and one of the following materials is chosen as the coating material for the electrodes of the electrostatic charging unit: titanium carbide, cerium hexaboride, yttrium hexaboride, lanthanum hexaboride and tungsten diboride.

This advantageous characteristic provides an alternative opportunity for the most efficient emission of electrons from negative electrodes in comparison with other materials.

There is also such a variant of the utility model, in which the coating of the electrodes of the electrostatic charging unit is made of a material used to cover photocathodes with a high quantum yield and with a thin film of a chemically inert substance transparent to the UV, visible and near-infrared regions of the spectrum. quantum yield (Ɣ) from 0.05 to 0.5. For example, a photocathode coating made of Cs ₃ Sb with a wavelength of 620-720 nm, a quantum yield (Ɣ) from 0.2 to 0.25; photocathode coating made of K ₂ CsSb - wavelength 650-700 nm, quantum yield from 0.3 to 0.4; photocathode coating made of GaAsP-Cs, wavelength 680 nm, quantum yield 0.5.

Thanks to such an advantageous characteristic, it becomes possible to use materials used for coating photocathodes, including those with a negative electron affinity (OSE) with a quantum yield (Ɣ) significantly superior to that of other semiconductors, which makes it possible to generate a relatively large emission current electrons. Quartz glasses KO1 can be used as a protective film for the emitter; organic conductive polymers: polyacetylene, polypyrrole, polyaniline, polycarbazole and other well-studied polymers used in solar cells. It has been established that vanadium glasses have electronic conductivity - the ionic conductivity has not been established. As a film, you can use gold, with a film thickness of 5 nm, in which the spectral transmittance of quanta with a wavelength of 253.6 nm to 643.8 nm is in the range from 0.542 to 0.690.

There is also such a variant of the utility model, in which one of the following materials is selected as a protective film for electrodes of the electrostatic charging unit: gold, osmium, rhodium, ruthenium, silver, with a film thickness less than or equal to 5 nm.

Thanks to this advantageous characteristic, an alternative possibility of using the materials appears.

There is also a variant of the utility model, in which a humidifier is located inside the body, that is, a container with an open surface.

Thanks to such an advantageous characteristic, it becomes possible to significantly increase the emission of electrons from the emitter, since during the adiabatic expansion of water vapor it cools and becomes supersaturated with further formation of fog droplets on condensation centers: solid particles, spores, microorganisms, and ions. This fog ionizes the emitter well, since the electron affinity of the surface of water droplets is 6 eV.

Brief description of the drawings.

Other distinctive features and advantages of the utility model clearly follow from the description given below by way of illustration and not being limiting, with references to the accompanying drawings, in which:

- fig. 1 depicts an electrostatic filter device and a diagram for connecting the device through a general-purpose electrical network.

- fig. 2 shows a removable collecting electrode,

- fig. 3 is a plot of the field versus distance from the emitting surface.

The figures indicate:

1 - case

2 - irradiation chamber

3 - entrance window

4 - exit window

5 - entrance airway labyrinth

6 - exit airway labyrinth

7 - fan

8 - emitter

9 - filter

10 - light source

11 - collecting electrode

12 - voltage source

13 - airway holes of the collecting electrode

According to figure 1, an electrostatic filter includes a housing 1 in which an irradiation chamber 2 is formed, the inner surface of which is covered with a material that reflects light radiation, airway labyrinths 5 and 6, a fan 7, an electrostatic charging unit (emitter) 8, a filter 9, a source light radiation 10, a unit for deposition of charged particles (collecting electrode) 11 and a voltage source 12.

The inner surface of the irradiation chamber 2 is covered with a material that reflects light radiation, and inside the housing 1 there is an emitter 8 connected to ground or output to the external environment through a voltage source 12, while the emitter 8, the collecting electrode 11, the airway labyrinths 5 and 6 of which the inner surface Coated with a material chemically inert with respect to atmospheric air substances and having an electron work function equal to or less than 3.1 eV for the coating of emission electrodes, and more than 6 eV for the coating of the inner surface of the irradiation chamber and at the surface of the collecting electrode.

The emitter 8 and the collecting electrode are connected to the housing 1 and the irradiation chamber 2 through insulators.

The inner surface of the irradiation chamber can be coated with aluminum.

One of the following materials can be selected as the emitter coating material: hafnium carbide, scandium diboride, niobium carbide, tantalum carbide, titanium carbide (powder), titanium oxide, tungsten diboride, zirconium carbide (powder), tungsten carbide, cerium hexaboride, hexaboride scandium, gadolinium hexaboride, yttrium hexaboride, lanthanum hexaboride, strontium hexaboride,

The collecting electrode can be made of aluminum.

For regular maintenance, the body 1 of the device is collapsible, and the collecting electrode is removable.

Implementation of the utility model.

The electrostatic filter works as follows. (An example of the device operation is given, which does not limit the application of the utility model).

Stage 1. Air taken from the room through the inlet window 3 is cleaned of dust in a general-purpose air purification filter 9.

Stage 2. Then he goes through the entrance airway labyrinths 5.

Stage 3. Air enters the irradiation chamber 2 and passes through the emitter, where molecules of oxygen, carbon dioxide and water, as well as solid particles, spores, microorganisms, atoms, molecules and ions of many harmful substances are charged and recharged by emission electrons.

Stage 4. Further, solid particles, spores, microorganisms, atoms, molecules and ions of many harmful substances charged and recharged by emission electrons are discharged and adsorbed on the collecting electrode, and the molecules of oxygen, carbon dioxide and water become neutral.

Stage 5. The purified air passes through the outlet air duct labyrinths 6 and is directed into the room under the action of the fan 7.

The inlet and outlet air duct labyrinths 5 and 6 prevent the penetration of ultraviolet radiation into the room, which allows people to be in the room during the operation of the electrostatic filter.

Industrial applicability.

The electrostatic filter can be practiced by a person skilled in the art and, when implemented, provides the claimed purpose. The possibility of implementation by a specialist in practice follows from the fact that for each feature included in the formula of a utility model on the basis of the description, a material equivalent is known, which allows us to conclude that the criterion "industrial applicability" for the utility model, as well as the criterion "completeness of disclosure" for utility model.

The proposed device also has additional advantages, expressed in the fact that:

1. An additional EDC is generated in the device due to the photoelectric effect. approximately equal to hν / ē, where hν is taken in electron volts. This E.D.S. remains even when the voltage source on the electrodes is turned off, but when the ultraviolet lamps are on.

2. An additional EDC is generated. between opposite tips of the emitter due to the effect of dragging free charge carriers by photons. It was found that if a beam of radiation passes along a semiconductor rod, then in this rod in the longitudinal direction a photo of the EDC will appear, creating a potential difference V.

V = -W ₀ / cen,

where W _{0 is the} radiation power in the beam per unit area,

n is the concentration of electrons,

e is the electron charge,

c is the speed of light.

3. The bactericidal efficiency of the proposed utility model is significantly higher than that of ultraviolet bactericidal recirculators, provided that a UV lamp is used as a source of light radiation. Destruction of microorganisms occurs on the precipitation electrode, which significantly increases the residence time of microorganisms under the influence of UV radiation and negative air ions.

4. Since the collecting electrode is grounded, the device enriches the air passing through it with negative air ions, due to the fact that the Earth's surface is negatively charged.

The power consumption of the device depends mainly on the power of the light source and the power of the fan.

The built-in electrostatic dust collector has a current voltage of 36 V to 220 V, depending on the layout options. As a grounding, in rooms, you can use the grounding of the general purpose electrical network, if present.

The electric current of the emission electrons generated by the emitter is between 1 μA and 15 μA, depending on the setting. The source of constant voltage can be both autonomous sources - primary current sources, storage batteries, and a general-purpose electrical network. The grounding material in contact with the external environment is selected for reasons of inertness and maximum electron affinity, in particular, aluminum with an Al ₂ O ₃ oxide film with A _B = 7.35 eV for the atmosphere and copper, nickel or platinum for contact with the earth's surface or water.

The spectral reflectance of Al with an Al ₂ O ₃ oxide film _of near-UV radiation with a quantum energy of 3.10 eV to 4.9 eV and visible light is in the range from 0.80 to 0.93. In addition, the reflectivity in the visible and near UV regions is high and only a small part is absorbed by the material.

Quantum yield (Ɣ) is the number of emitted electrons per photon incident on the surface of the body.

In the visible and near UV regions, Ɣ is less than or equal to 0.001 electron / photon. Taking into account multiple reflections in this installation, the quantum efficiency Ɣ increases significantly, and taking into account the supply of negative potential to the electrodes, Ɣ increases even more, depending on the voltage value.

The electron affinity energy is positive for an oxygen molecule and is equal to 0.44 eV, for a water molecule it is 0.8 eV, and for carbon dioxide it is 0.51 eV and is absent or negative for argon and nitrogen, therefore, stable negative air ions can only be found in molecules of oxygen, water and carbon dioxide with the addition of emission electrons, which is used in this utility model.

In the absence of an electric field, the potential distribution U near the metal surface has the form of a hyperbola (1), (Fig. 1.), which is associated with the action of electric forces. attraction, also called the forces of the mirror image (when the electron leaves the emitter in a solid, a charge is induced, which is its mirror image). When an external uniform electric field of intensity E is imposed, the potential barrier is depicted by curve (2), (Fig. 1.) and the work function decreases by ΔΦ = e3 / 2E1 / 2 (e is the electron charge). The last expression for metals is applicable at E <107 V / m, when field emission begins. If a heated cathode serves as the electron current source, then due to the Schottky effect (SHE), the current increases from I0 to I = I0exp (e3 / 2E1 / 2 / kT), where T is the cathode temperature, k is the Boltzmann constant. In the case of a photocathode, the threshold of the photoelectric effect shifts towards longer wavelengths and a corresponding increase in the photoelectron current occurs when the cathode is illuminated.

When a metal surface is covered with a thin adsorbent film of an inhomogeneous structure in a sh. anomalies arise associated with the complex interaction of local electric fields between clean and film-coated surface areas.

In semiconductors Sh. E. more complex than metals. In them, along with a decrease in the external potential barrier, both partial penetration of the electric field into the semiconductor to a depth depending on the concentration of free charge carriers and its partial screening by a layer of surface charges are observed. As a result, the electric field, as a rule, has a greater influence on the work function of the electron, and, consequently, on the strength of the electron current.

See fig. 3, where, Φ is the total work function; Z is the distance from the emitting surface.

Also, the radius of curvature affects the electric field at the surface of the emission electrode. For a spherical surface, E = U / R, where E is the electric field strength, U is the potential difference between the electrodes, R is the radius of curvature. Cold field emission is observed at values of E from 10 ⁶ -10 ⁸ V / m. For example, U = 220 V, R = 2.2 × 10 ^-6 m, E = 10 ⁸ V / m. These considerations, in particular, underlie the essence of this utility model.

Thus, due to the above signs, the claimed technical result is achieved - an increase in the efficiency of purification, disinfection and improvement of the quality of the treated air by neutralizing harmful positively charged light and heavy air ions and purifying it from dust and spores. This is achieved, in particular, due to the fact that in the installation for increasing the emission of electrons from the negative electrode, in addition to the potential difference supplied to the electrodes, an external photoelectric effect is also used and chemically inert materials with a minimum work function of the electron are selected, which allows a significant decrease in the operating voltage at the electrodes electrostatic dust collector.

Claims (12)

1. An electrostatic filter for air purification, which includes a housing containing an inlet window, an outlet window, a filter and a fan, an irradiation chamber is formed in the housing, which has an electrostatic charging unit, a charged particle deposition unit, characterized in that a light source is located inside the housing and airway absorption labyrinths, wherein the inner surface exposure material is covered chamber reflecting light radiation, the electrodes of the electrostatic charging unit and the electrodes of the charged particle precipitation unit made of materials chemically inert with respect to the outside substances and having a work function (A _B) less than or equal to 3.10 eV for the coating material of the electrodes of the electrostatic charging unit, and for the coating of the electrodes of the unit for deposition of charged particles and the inner surface of the irradiation chamber А _В more than 6 eV. 2. An electrostatic filter according to claim 1, characterized in that the light source is configured to create a maximum radiation in the range from 400 nm to 420 nm. 3. An electrostatic filter according to claim 1, characterized in that the light source is made in the form of an ozone-free ultraviolet lamp, made with a maximum of short-wave ultraviolet radiation at 253.7 nm, which corresponds to a light quantum energy of 4.9 eV, and equipped with a flask made made of glass, filtering out a spectral line of 185 nm, that is, quanta, when interacting with which ozone is formed. 4. An electrostatic filter according to claim 1, characterized in that the electrostatic charging unit is connected to a voltage source through a voltage regulator. 5. An electrostatic filter according to claim 1, characterized in that the inner surface of the irradiation chamber and the surface of the electrodes of the charged particle deposition unit are coated with aluminum. 6. Electrostatic filter according to claim 1, characterized in that the material having the work function of the electron less than or equal to 3.1 eV is selected as the coating material for the electrodes of the electrostatic charging unit. 7. Electrostatic filter according to claim 6, characterized in that one of the following materials is selected as the coating material for electrodes of the electrostatic charging unit: scandium diboride, niobium carbide, titanium carbide, titanium oxide, tungsten diboride, hafnium carbide, cerium hexaboride, scandium hexaboride , gadolinium hexaboride, yttrium hexaboride, lanthanum hexaboride, strontium hexaboride. 8. Electrostatic filter according to claim 7, characterized in that titanium or another resistant metal is selected as the material of electrodes of the electrostatic charging unit, and one of the following materials is selected as the coating material for electrodes of the electrostatic charging unit: titanium carbide, cerium hexaboride, yttrium hexaboride , lanthanum hexaboride and tungsten diboride. 9. Electrostatic filter according to claim 6, characterized in that the coating of electrodes of the electrostatic charging unit is made of a material used to coat photocathodes with a high quantum yield and with the deposition of a thin film of a chemically inert substance transparent to UV, visible and near infrared regions spectrum having a quantum yield (Ɣ) from 0.05 to 0.5. 10. Electrostatic filter according to claim 9, characterized in that one of the following materials is selected as a protective film for electrodes of the electrostatic charging unit: gold, osmium, rhodium, ruthenium, silver, with a film thickness less than or equal to 5 nm. 11. An electrostatic filter according to claim 1, characterized in that the electrodes of the electrostatic charging unit are made of plates having a broken or sinusoidal surface with sharp edges at the ends. 12. An electrostatic filter according to claim 1, characterized in that a humidifier is located inside the housing.

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