RU2174873C1 - Electrostatic precipitator with increased size of precipitation area - Google Patents

Abstract

FIELD: electrostatic separation of materials. SUBSTANCE: invention relates to devices for electrostatic separation of materials with entrapping of dispersed particles from air using electrostatic effect, such as devices for air cleaning from aerosol particles in air conditioning and ventilation systems. Proposed electrostatic precipitator featuring increased-size precipitation area has supply system, contact system, alternating potential and grounded plate electrodes installed at a distance of 5 mm from one another, minimum, in box-type housing vertically relative to housing, in parallel to air flow and mechanically secured in housing. Electrodes are made from dielectric material, thickness 0.5 mm, minimum neutral electrodes installed in between. Neutral electrodes are parallel to plate electrodes, are equal in size to plate electrodes and are installed at equal distance from two neighbor electrodes. Electrodes can be made in form of horizontal late inserts whose length does not exceed distance between electrodes, made in form of rectangle with rounded-off corners and installed symmetrically relative to plate in slots made in rows, both vertically and horizontally, in plate electrodes. Inserts in neighbor plates are staggered relative to each other. EFFECT: reduced energy consumption, improved safety, increased size of precipitation area, enhanced efficiency of air cleaning, higher dust capacity of plant, possibility of use of precipitators in internal recirculation system. 3 dwg

Description

 The device relates to the field of electrostatic separation of materials, to the separation of dispersed particles from air using the electrostatic effect, specifically to devices for cleaning air from aerosol particles in air conditioning and ventilation systems.

 For example, an electrostatic filter [1] is known, in which the first and second plate electrodes are made of a very thin sheet of resinous material on which an even thinner conductive layer is applied. The length of the electrode is much greater than the width. The surfaces of the first and second electrodes are given a position, a curvilinear configuration and such dimensions that their sections are located one against the other, while passages located across the width of the electrodes are formed between opposite sections of the surfaces. Spacers attached to the first electrode provide the rigidity of some of its sections with respect to others, and the second electrode is rigidly attached to the first. Spacers are two elastic insulating tapes, the width of which is much smaller than the width of the electrodes. The tapes are corrugated and glued to the first and second electrodes.

 In this electrostatic filter, alternating plates are a series of sheets on which resinous material is applied. Spacers are placed between the plates to exclude the possibility of their contact, the plates are rolled up in the form of a roll.

 The disadvantage of this filter is that it is difficult to manufacture both the plates and the filter itself to obtain the desired configuration of the plates and the passages between them.

 Also known electrostatic dust collector [2], containing precipitation electrodes made in the form of endless tapes of dielectric material, and dust brushes. In this case, the electrodes are located coaxially, the brushes are placed between them, and the dielectric constant of the material of one of the dielectrics is greater, and the other is less than the dielectric constant of the brushes.

 Here, like the first analogue, the plates are made in the form of endless ribbons, but from a thin dielectric material, and the plates are charged due to friction, the distance between the plates is not indicated.

 In this device, the plates are charged due to the triboelectric effect, i.e. it is impossible to increase the voltage to increase the efficiency of the filter, it is also difficult to increase the area of the deposited plates without a significant change in the size of the filter.

 The closest known to the proposed invention is an electrostatic precipitator [3], adopted by us as a prototype. The improved second stage of the two-stage electrostatic precipitator contains a closed casing made of non-conductive material and provided with an input and an output on one axis. On the inner sides of the opposite walls of the casing in the direction from the entrance to the exit, a large number of equally spaced grooves are made, into which collector plates installed in the casing are inserted with the edges. By means of the grooves, all the plates are arranged mutually parallel in the direction from the entrance to the exit. Each plate is made of a non-conductive material or metal and is coated externally with a layer of another material having a low conductivity.

 Compared to the previous one, a voltage from 3 to 7 kV is applied to the plates in this electrostatic precipitator, the plates are made in the form of plane-parallel electrodes, the plate thickness is at least 0.5 mm, but this device has an I zone, i.e., an artificial particle charging zone, and plates to reduce the probability of breakdown are made of several layers. When installing the manifold, it is necessary to comply with the air inlet and outlet.

 The proposed device, like the prototype, contains a power supply system, a contact system, alternating potential and grounded plate electrodes, mounted at a distance of at least 5 mm from each other in a box-shaped case, vertically relative to it and parallel to the air flow and mechanically fixed in it.

 The tasks solved by this device: minimum power consumption, increased electrical safety, increased working area of particle deposition, increased efficiency of air purification, increased dust absorption of the installation, the use of filters in the internal recirculation system, expansion of the scope.

 The proposed device differs from the known one in that the electrodes are made of a dielectric material with a thickness of at least 0.5 mm and neutral electrodes are installed between them, which are parallel to and equal to the plate electrodes and are installed at the same distance from two adjacent or in the form of horizontal plate inserts, length which are not greater than the distance between the electrodes, having the shape of a rectangle with rounded corners and installed symmetrically with respect to the plate in the slot, which are made in a row vertically and horizontally in the electrode plates, wherein the insert adjacent layers are staggered relative to each other.

 The proposed device contains new features, namely, the electrodes are made of a dielectric material, their thickness is at least 0.5 μm, neutral electrodes are installed between the electrodes, which can either be parallel to the plate electrodes, equal to them and installed in the middle between two adjacent ones, or in the form of horizontal plate inserts, and the inserts have the shape of a rectangle with rounded edges and their length is not more than the distance between two adjacent electrodes and they are installed symmetrically in the slot, i.e. the inserts have the same length on either side of the plate, and the slots are made in rows both vertically and horizontally in the plate electrodes, while the inserts of adjacent plates are staggered relative to each other.

 The execution of plates of a dielectric with a thickness of at least 0.5 mm makes it possible to increase the voltage supplied to the plates, while it does not become more dangerous and breakdown occurs at 18 kV.

 The implementation of the plates of the dielectric is known, for example, from [2], however, the implementation of the flat electrodes of the proposed filter from a dielectric material with a thickness of at least 0.5 mm, this thickness ensures the rigidity of the plates, makes it possible to make plate electrodes and install them parallel to each other and side walls duct, apply the voltage required for the filter to work.

 The installation of additional neutral plates between two adjacent plates that are parallel to the plate electrodes, equal to them and installed at the same distance from two neighboring ones, leads to the fact that the neutral plates are polarized so that the sides of the plate have a charge opposite to the charge of the neighboring plate. Thus, the total area of particle deposition increases, the efficiency of air cleaning increases, the dust absorption of the installation increases, while the energy consumption does not increase, and electrical safety increases, because a neutral dielectric plate is installed between two charged plates.

 Installation of additional neutral plates in the form of plate inserts, the length of which is no more than the distance between the electrodes, having the shape of a rectangle with rounded corners and installed symmetrically relative to the plate in the slots, which are made in rows both vertically and horizontally in the plate electrodes, while the inserts of adjacent plates are staggered relative to each other, leading, as in the first embodiment, to an increase in the total area of particle deposition, an increase in the efficiency of cleaning ear, due to the fact that the inserts acquire a charge of the plates on which they are installed. Energy consumption does not increase, and electrical safety increases by increasing the distance between the electrodes.

 However, for this invention, the presence of each of these characteristics is necessary, and all together is sufficient to solve the specified technical problem, while maintaining the unity of the invention.

 An important distinguishing feature of the proposed filter is the use of convective (thermal) air flows in small rooms. The filter can be installed on heating devices, as well as heat exchangers for refrigerators, lighting devices and others where there are convective flows. In addition, the filter can be used in a forced ventilation system. For the proposed filter does not require an additional energy source to create the movement of air flows, and works on natural heat (convective) flows. The minimum energy consumption leads to the expansion of the scope of the proposed filters and can be used in any apartment, office, child care facilities, small production facilities, etc. A feature is also that the filter can work in any direction of air flow. Thus, the proposed filters can be used in an internal recirculation system without external air entering the room. This is a very important point for ecologically unfavorable areas where the outside air is not always clean. In addition, in winter there is no need to ventilate the room, which already leads to great savings in heat and energy. And for rooms such as nurseries, kindergartens and schools, the likelihood of colds is significantly reduced. It is also very important that in addition to cleaning the air from dust, disinfection occurs, i.e. purification from viral, aerogenic infections and other microbes, as It is known that viruses and microbes can be in the air stream only adhered to dust particles [4].

 In FIG. 1 and 2 show an electrostatic filter with an increased deposition area, the proposed device contains a box 1, grounded dielectric electrodes 2, potential dielectric electrodes 3, additional plates 4 in the form of neutral or additional electrodes, a power source 5. In FIG. Figure 3 shows the location of the additional 4 electrodes on the grounding 2 and potential 3 plates.

 The proposed device works as follows: aerosol particles having a bipolar electric natural charge fall into the interelectrode gap, are polarized and deposited on one or another precipitation electrode 2, 3 or 4 depending on the sign of the particle’s charge, i.e. positively charged particles are deposited on potential plates either on the negatively charged side of the neutral plate, and vice versa, particles having a negative charge are deposited on grounded plates or on the positively charged side of the neutral plate.

 In FIG. 2 - when installing additional plates in the form of inserts, the latter acquire the sign of the plate on which they are installed. In this case, the deposition of particles occurs on the corresponding plate.

 The device can be performed as follows. The body is made of PCB, which contains a package of 24 dielectric plates measuring 9 x 13.5 cm each (6 potential plates, 6 grounded and 12 neutral) or from 12 alternating potential and grounded plates with plate inserts on the electrostatic filter. The thickness of the plates is 0.5 mm, on the plates there are through slots 6 mm in size; 9 plate inserts on a grounded plate and 12 on a potential plate. The distance between the inserts on the grounded plate horizontally is 20 mm, vertically 35 mm, and on the potential plate 13 mm and 35 mm, respectively. The plate insert measures 10 x 6 mm. The interelectrode distance is 5 mm. A voltage of 10 kV is supplied to the electrodes from a high voltage power source.

Sources of information
1. US patent N 4234324, MKI ⁶ B 03 C 3/45, ELEKTROSTATIC FILTER, decl. 11/18/80.

 2. Copyright certificate N 581971. cl. B 03 C 3/00, 1977. Electrostatic dust collector, Applic. 07/19/74, publ. 11/30/77, bull. N 44.

 3. US patent. US 4,166,729 A (The United States of America as represented by the Secretary of the Navy), 09/04/79.

 4. Ogarkov V.I., Gapochko K.G. Aerogenic infection. - M.: Medicine, 1975 .-- 232 p.

Claims (1)

 An electrostatic filter with an increased deposition area, comprising a power system, a contact system, alternating potential and grounded plate electrodes, installed at a distance of at least 5 mm from each other in a box-shaped housing, vertically relative to it and parallel to the air flow, mechanically fixed in it, characterized in that the electrodes are made of a dielectric material with a thickness of at least 0.5 mm and neutral electrodes are installed between them, which are parallel to the plate electrodes rods are equal to them and are installed at the same distance from two adjacent or in the form of horizontal plate inserts, the length of which is no more than the distance between the electrodes, having the shape of a rectangle with rounded corners and installed symmetrically with respect to the plate in the slot, which are made in rows both vertically and and horizontally in the plate electrodes, while the inserts of adjacent plates are staggered relative to each other.

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