Difficulties in cleaning the air in the workplace

Industrial air purification is a very difficult task, since it involves the elimination of all known types of pollutants from it at once. Pollutants are classified into the following types:

• gases;
• Aerosols (mechanical particles suspended in the air);
• organic compounds.

It is necessary to remove them all, bringing the air to the required sanitary and technological standards. This is due to the need to use complex systems of mechanical, physical and chemical treatment.

In industrial air purification, the greatest difficulty is the removal and neutralization of organic compounds. Under organic compounds, it is customary to understand microorganisms and their metabolic products, which are complex biochemical molecular structures scattered in the air in the form of clots of various dispersion.

The removal of gases and aerosols is also associated with considerable difficulties, especially when you consider that we are talking about air purification in production, which means that the scale of pollution is very high. Equipment costs are comparable to its size. But he also needs maintenance, which is notable for its considerable complexity, and therefore inevitably entails new, consistently high spending!

Industrial air purification using advanced technologies

It is also difficult to solve the issue of air purification in production because each enterprise has a unique composition of pollution, which means that there cannot be universal solutions. This was thought quite recently, until the first PlazmaiR Industry units appeared on sale, capable of purifying the air from all three types of pollutants, eliminating them equally effectively.

The mentioned technology of air purification in production has become a real discovery, not only in Russia, but also in the West, where the issues of eliminating harmful production factors are approached with traditionally high responsibility. At the moment, PlazmaiR installations have no analogues abroad, so there is simply nothing to compare them with.

It should be added here that the principle of operation of these installations is not focused exclusively on air purification in production, therefore their scope is not limited to industry only. PlazmaiR units can be used in residential and public buildings, such as restaurants or supermarkets, achieving no less results!

Air purification in production with PlazmaiR Industry installations

The high efficiency of the PlazmaiR Industry units used for air purification in production is due to an integrated approach to the task. Structurally, PlazmaiR installations consist of three blocks, each of which eliminates pollutants of a certain type:

• Mechanical filtration unit (preliminary cleaning);
• Block of physical decomposition (plasma cleaning);
• Air gas composition normalization unit (catalytic purification).

To purify the air in production, associated with high humidity in technological rooms, it is necessary to use PlazmaiR units with additionally installed dehumidification modules. If the air in technological rooms is saturated with vapors of aggressive substances, installations made of highly resistant materials are needed.

All PlazmaiR Industry units used for industrial air purification are manufactured by Perspektiva in Russia, without the involvement of contractors. The equipment produced by it is adapted for operation in the conditions of our country, and its maintenance is much cheaper than the maintenance of other industrial air purification systems.

Dust forms / accumulates almost everywhere and always - and each of us has come across this sad truth in everyday life. In production, everything is even worse, since any transshipment of solid raw materials or finished products (not to mention mechanical processing) is associated with the formation of one or another amount of dust. This dust can vary in size and fractional composition of particles, density, etc., but the main thing is in the degree of its potential danger.

Not everyone imagines that if we are talking about fine dust from any combustible materials (flour particles, powdered sugar, wood dust, etc.), then when a certain volume concentration of a suspension of such dust in the air is exceeded, it turns into ready-made ammunition for a volumetric explosion , just waiting for its detonator. Safety courses have preserved for us a lot of cautionary tales about dust-induced explosions in bakeries, flour mills, woodworking industries, etc. - An inquisitive reader will be able to find a lot of similar documentary stories on the Web.

How to deal with dust in factories

There are many types of different types of dust collectors, the most common of which include:

• cyclones - devices for medium / coarse air purification from non-coalescing and non-fibrous dust due to centrifugal separation in a rotating air stream;
• rotoclones (rotary dust collectors) - a kind of centrifugal fans, used to purify the air from coarse dust, due to the forces of inertia;
• mechanical filters - devices that use mesh and porous materials with different characteristic mesh / hole sizes to separate dust particles from a passing through air flow (in the range of filters for industrial aspiration systems can be found here - http://ovigo.ru/ochistka-vozduxa- ot-pyili/);
• scrubbers - devices that use sprayed liquid to clean the air;
• electrostatic precipitators - devices built mainly around the use of the so-called. "corona discharge" in gases and used for the deposition of very fine dust by giving it an electric charge;
• ultrasonic filters are fine cleaning devices that use high-intensity ultrasonic exposure to coagulate a suspension of especially small particles.

Of course, the list above is not exhaustive - and the interested reader should refer to the literature for more details.

Specificity of dust collectors

It is important to understand that almost any dust is a complex, polydisperse system, the macroscopic properties of which can change very significantly due to external factors. Thus, a change in air humidity can both enhance dust formation and contribute to the agglomeration of particles, and a simple change in the speed of the flow carrying them can affect the magnitude of the accumulated volumetric triboelectric charge. It would be a big mistake to assume that dust collectors for one type of dust/condition can easily be used under other circumstances with the same efficiency. In practice, the vast majority of dust collectors and aspiration plants first go through the stage of engineering and mathematical calculations and modeling, thus optimizing for a specific consumer and the specifics of his production conditions. It follows that when ordering such devices, it is necessary to communicate with the engineering and technical staff of a potential supplier, talking about the task at hand in the totality of the existing conditions. For example, in the case of a planned increase in production activity, the system should initially be designed in a modular way, i.e. with the possibility of section-by-section increase in plant productivity. Of course, only professionals can tell the consumer the most optimal dust collection methods and effective types of installations - however, for this they must be provided with accurate technical information in a timely manner.

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Methods for cleaning the air from dust

For the neutralization of aerosols (dusts and mists), dry, wet and electrical methods are used. In addition, the devices differ from each other both in design and in the principle of sedimentation of suspended particles. The operation of dry apparatuses is based on gravitational, inertial and centrifugal mechanisms of sedimentation or filtration mechanisms. In wet dust collectors, dusty gases come into contact with a liquid. In this case, deposition occurs on drops, on the surface of gas bubbles or on a liquid film. In electrostatic precipitators, the separation of charged aerosol particles occurs on the collecting electrodes.

Dry mechanical dust collectors include devices that use various deposition mechanisms: gravitational, inertial and centrifugal.

Inertial dust collectors. With a sharp change in the direction of the gas flow, dust particles under the influence of inertial force will tend to move in the same direction and, after turning the gas flow, fall into the bunker. The effectiveness of these devices is small.

Louvre devices. These devices have a louvered grille consisting of rows of plates or rings. The purified gas, passing through the grate, makes sharp turns. Due to inertia, dust particles tend to maintain their original direction, which leads to the separation of large particles from the gas flow, the same is facilitated by their impact on the inclined planes of the grating, from which they are reflected and bounce away from the slots between the shutter blades. As a result, gases are divided into two streams. The dust is mainly contained in the stream, which is sucked off and sent to the cyclone, where it is cleaned of dust and again merged with the main part of the stream that has passed through the grate. The velocity of the gas in front of the louver must be high enough to achieve the effect of inertial separation of dust.

Typically, louvered dust collectors are used to capture dust with a particle size of >20 µm.

The efficiency of particle collection depends on the efficiency of the grate and the efficiency of the cyclone, as well as on the proportion of gas drawn off in it.

Cyclones. Cyclone devices are the most common in industry.

According to the method of supplying gases to the apparatus, they are divided into cyclones with spiral, tangential and helical, as well as axial supply. Cyclones with axial gas supply operate both with and without gas return to the upper part of the apparatus.

The gas rotates inside the cyclone, moving from top to bottom and then moving up. Dust particles are thrown by centrifugal force towards the wall. Usually, in cyclones, the centrifugal acceleration is several hundred or even a thousand times greater than the acceleration of gravity, so even very small dust particles are not able to follow the gas, but move towards the wall under the influence of centrifugal force.

In industry, cyclones are divided into high-efficiency and high-performance.

At high flow rates of the gases to be purified, a group arrangement of apparatuses is used. This allows not to increase the diameter of the cyclone, which has a positive effect on the cleaning efficiency. The dusty gas enters through a common collector and then is distributed between the cyclones.

Battery cyclones - combining a large number of small cyclones into a group. Reducing the diameter of the cyclone element aims to increase the cleaning efficiency.

Vortex dust collectors. The difference between vortex dust collectors and cyclones is the presence of an auxiliary swirling gas flow.

In the nozzle-type apparatus, the dusty gas flow is swirled by a vane swirler and moves upward, being exposed to three jets of secondary gas flowing from tangentially located nozzles. Under the action of centrifugal forces, the particles are thrown to the periphery, and from there into the spiral flow of secondary gas excited by the jets, directing them down into the annular annulus. The secondary gas in the course of a spiral flow around the stream of purified gas gradually completely penetrates into it. The annular space around the inlet pipe is equipped with a retaining washer, which ensures the irreversible descent of dust into the hopper. Blade-type vortex dust collector is characterized by the fact that the secondary gas is taken from the periphery of the purified gas and supplied by an annular guide vane with inclined blades.

As a secondary gas in vortex dust collectors, fresh atmospheric air, part of the purified gas or dusty gases can be used. The most economically advantageous is the use of dusty gases as a secondary gas.

As with cyclones, the efficiency of vortex devices decreases with increasing diameter. There may be battery installations consisting of separate multi-elements with a diameter of 40 mm.

Dynamic dust collectors. Cleaning of gases from dust is carried out due to centrifugal forces and Coriolis forces arising from the rotation of the impeller of the draft device.

The most widely used smoke exhauster-dust collector. It is designed to capture dust particles >15 µm in size. Due to the pressure difference created by the impeller, the dusty flow enters the "snail" and acquires a curvilinear motion. Dust particles are thrown to the periphery under the action of centrifugal forces and, together with 8-10% of the gas, are discharged into a cyclone connected to the snail. The purified gas flow from the cyclone returns to the central part of the cochlea. Purified gases through the guide apparatus enter the impeller of the smoke exhauster-dust collector, and then through the casing of emissions into the chimney.

Filters. The operation of all filters is based on the process of gas filtration through a partition, during which solid particles are retained, and the gas passes completely through it.

Depending on the purpose and the value of the input and output concentrations, filters are conditionally divided into three classes: fine filters, air filters and industrial filters.

Sleeve filters are a metal cabinet divided by vertical partitions into sections, each of which contains a group of filter sleeves. The upper ends of the sleeves are plugged and suspended from a frame connected to a shaking mechanism. At the bottom there is a dust hopper with an auger for unloading it. The shaking of the sleeves in each of the sections is performed alternately. (pic 6)

Fiber filters. The filter element of these filters consists of one or more layers in which fibers are uniformly distributed. These are volumetric filters, since they are designed to trap and accumulate particles mainly throughout the entire depth of the layer. A continuous layer of dust is formed only on the surface of the densest materials. Such filters are used at a concentration of the dispersed solid phase of 0.5-5 mg/m 3 and only some coarse fibrous filters are used at a concentration of 5-50 mg/m 3 . At such concentrations, the main part of the particles has a size of less than 5-10 microns.

There are the following types of industrial fiber filters:

Dry - fine-fiber, electrostatic, deep, pre-filters (pre-filters);

Wet - mesh, self-cleaning, with periodic or continuous irrigation.

The filtration process in fibrous filters consists of two stages. At the first stage, the trapped particles practically do not change the structure of the filter over time; at the second stage of the process, continuous structural changes occur in the filter due to the accumulation of trapped particles in significant quantities.

Grainy filters. They are used for gas purification less often than fibrous filters. Distinguish between packed and rigid granular filters.

Hollow scrubbers. Hollow jet scrubbers are the most common. They represent a column of circular or rectangular cross section, in which contact is made between gas and liquid droplets. According to the direction of movement of gas and liquid, hollow scrubbers are divided into counter-flow, direct-flow and transverse liquid supply.

Packed scrubbers are columns with bulk or regular packing. They are used to capture well-wetted dust, but at a low concentration.

Gas scrubbers with a movable nozzle are widely used in dust collection. Balls made of polymeric materials, glass or porous rubber are used as nozzles. The nozzle can be rings, saddles, etc. The density of the nozzle balls should not exceed the density of the liquid.

Scrubbers with a movable ball nozzle of a conical shape (KSSH). To ensure the stability of operation in a wide range of gas velocities, improve the distribution of liquid and reduce the entrainment of splashes, apparatuses with a movable ball nozzle of a conical shape are proposed. Two types of devices have been developed: injector and ejection

In an ejection scrubber, the balls are irrigated with liquid, which is sucked from a vessel with a constant level of gases to be cleaned.

Disc scrubbers (bubbling, foam). The most common froth machines are with dip trays or overflow trays. Plates with overflow have holes with a diameter of 3-8 mm. Dust is captured by the foam layer, which is formed by the interaction of gas and liquid.

The efficiency of the dust collection process depends on the size of the interfacial surface.

Foam machine with foam stabilizer. A stabilizer is installed on the failed grating, which is a honeycomb grating of vertically arranged plates that separate the cross section of the apparatus and the foam layer into small cells. Thanks to the stabilizer, there is a significant accumulation of liquid on the plate, an increase in the height of the foam compared to a failed plate without a stabilizer. The use of a stabilizer can significantly reduce water consumption for irrigation of the apparatus.

Gas scrubbers of shock-inertial action. In these devices, the contact of gases with a liquid is carried out due to the impact of a gas flow on the surface of the liquid, followed by the passage of a gas-liquid suspension through holes of various configurations or by direct removal of the gas-liquid suspension to the liquid phase separator. As a result of this interaction, drops with a diameter of 300–400 μm are formed.

Gas scrubbers of centrifugal action. The most common are centrifugal scrubbers, which can be divided into two types according to their design: 1) devices in which the gas flow is swirled using a central blade swirler; 2) devices with lateral tangential or volute gas supply.

High-speed scrubbers (Venturi scrubbers). The main part of the devices is a spray pipe, which provides intensive crushing of the irrigated liquid by a gas stream moving at a speed of 40-150 m/s. There is also a drop catcher.

Electrostatic precipitators. Purification of gas from dust in electrostatic precipitators occurs under the action of electrical forces. In the process of ionization of gas molecules by an electric discharge, the particles contained in them are charged. Ions are absorbed on the surface of dust particles, and then, under the influence of an electric field, they move and are deposited to the collecting electrodes.

The following methods are used to neutralize exhaust gases from gaseous and vaporous toxic substances: absorption (physical and chemisorption), adsorption, catalytic, thermal, condensation and compression.

Absorption methods for cleaning exhaust gases are divided according to the following criteria: 1) by the absorbed component; 2) according to the type of absorbent used; 3) by the nature of the process - with and without gas circulation; 4) on the use of the absorbent - with regeneration and its return to the cycle (cyclic) and without regeneration (non-cyclic); 5) on the use of captured components - with and without recovery; 6) by type of recovered product; 7) on the organization of the process - periodic and continuous; 8) on the design types of absorption equipment.

For physical absorption, water, organic solvents that do not react with the extracted gas, and aqueous solutions of these substances are used in practice. In chemisorption, aqueous solutions of salts and alkalis, organic substances, and aqueous suspensions of various substances are used as an absorbent.

The choice of purification method depends on many factors: the concentration of the extracted component in the exhaust gases, the volume and temperature of the gas, the content of impurities, the presence of chemisorbents, the possibility of using recovery products, the required degree of purification. The choice is made on the basis of the results of technical and economic calculations.

Adsorption gas purification methods are used to remove gaseous and vaporous impurities from them. The methods are based on the absorption of impurities by porous adsorbent bodies. Purification processes are carried out in batch or continuous adsorbers. The advantage of the methods is a high degree of purification, and the disadvantage is the impossibility of purification of dusty gases.

Catalytic purification methods are based on chemical transformations of toxic components into non-toxic ones on the surface of solid catalysts. Gases that do not contain dust and catalyst poisons are subjected to cleaning. Methods are used to purify gases from oxides of nitrogen, sulfur, carbon and organic impurities. They are carried out in reactors of various designs. Thermal methods are used to neutralize gases from easily oxidized toxic impurities.

Methods for cleaning the air from dust when released into the atmosphere

To clean the air from dust, dust collectors and filters are used:

Filters are devices in which dust particles are separated from air by filtration through porous materials.

Types of dust collectors:

The main indicators are:

productivity (or throughput of the apparatus), determined by the volume of air that can be cleaned of dust per unit of time (m 3 / hour);

aerodynamic resistance of the apparatus to the passage of the cleaned air through it (Pa). It is determined by the pressure difference at the inlet and outlet.

overall cleaning coefficient or overall efficiency of dust collection, determined by the ratio of the mass of dust captured by the device C y to the mass of dust that entered it with polluted air C in: C y /C in x 100 (%);

fractional cleaning coefficient, i.e. the efficiency of dust collection of the apparatus in relation to fractions of different sizes (in fractions of a unit or in%)

Dust collection chambers, dust collection efficiency - 50 ... 60%. The principle of cleaning is the outflow of dusty air from the chamber at a speed lower than the speed of dust soaring, i.e. dust has time to settle (see Fig. 1).

Cyclones - dust collection efficiency - 80...90%. The principle of cleaning is the rejection of heavy dust particles on the walls of the cyclone during the swirling of the flow of dusty air (see Fig. 2). The hydraulic resistance of cyclones ranges from 500... 1100 Pa. They are used for heavy dusts: cement, sand, wood…

Bag filters (for capturing dry non-coalescing dusts) dust collection efficiency - 90...99%. The principle of cleaning is the retention of dust particles on the filter elements (see Fig. 3). The main working elements are cloth sleeves suspended from a shaking device. They are used for heavy dusts: wood, flour, …

The hydraulic resistance of the filter, depending on the degree of dusting of the sleeves, varies within 1...2.5 kPa.

Filter cyclones - a combination of a cyclone (separation of heavy particles) and a bag filter (separation of light particles). See fig. 3.

Electric filters - the separation of dust particles from the air is carried out under the influence of an electrostatic field of high tension. In a metal case, the walls of which are grounded and are collecting electrodes, there are corona electrodes connected to a direct current source. Voltage - 30...100 kV.

An electric field is formed around the negatively charged electrodes. The dusty gas passing through the electrostatic precipitator is ionized and the dust particles acquire negative charges. The latter begin to move towards the filter walls. Collecting electrodes are cleaned by tapping or vibrating them, and sometimes by washing with water. aerosol filter scrubber

Dust collection efficiency - 99.9%. Low hydraulic resistance 100...150 Pa,

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Air purification from dust can be carried out both when outside air is supplied to the room, and when dusty air is removed from it. In the first case, the protection of workers in industrial premises is ensured, and in the second, the protection of the surrounding atmosphere.

Universal dust arresters suitable for all types of dust and for any initial concentration do not exist. Each of these devices is suitable for a certain type of dust, initial concentration and required degree of purification.

An important indicator of the operation of dedusting equipment is the air purification coefficient, which is determined by the formula

Kf = ((q1-q2)/q1)100%,

where q1 and q2 are the content of ash before and after cleaning, mg/m3.

Air purification from dust can be coarse, medium and fine. Coarse air purification retains coarse dust (particle size > 100 µm). Such cleaning can be used, for example, as a preliminary for heavily dusty air during multi-stage cleaning. With medium cleaning, dust with a particle size of up to 100 microns is retained, and its final content should not exceed 100 mg/m3. Fine cleaning is such cleaning, in which very fine dust (up to 10 microns) is retained with a final content in the air of supply and recirculation systems of up to 1 mg/m3.

Dust removal equipment is divided into dust collectors and filters.

Dust collectors. Dust collectors are devices whose operation is based on the use of gravity or inertial forces for the deposition of dust particles, separating dust from the air flow when changing the speed (in dust sedimentation chambers) and direction of its movement (single and battery cyclones, inertial and rotary dust collectors).

Dust collectors are used when the dust content in the exhaust air is more than 150 mg/m3.

Dust chambers. These chambers are used for settling coarse and heavy dust with a particle size of more than 100 µm (Fig. 11, a). The speed of dusty air in the cross section of the chamber is assumed to be small, about 0.5 m/s, so that the dust can settle in the chamber before it leaves it. Therefore, the dimensions of the chambers are quite large, which limits their use, despite the obvious advantages - low hydraulic resistance, cheap operation and ease of maintenance.

The cleaning efficiency can be increased (up to 80-95%) if the chamber is made of the labyrinth type (Fig. I, b), although this entails an increase in hydraulic resistance.

Inertial dust collectors. Such a dust collector (Fig. 11, c) is a set of truncated cones 1 installed in series in such a way that gaps 2 are formed between them. Dusty air enters through hole 5. Dust separation is based on a change in the direction of movement of dusty air, while suspended dust particles , having a much greater inertia force than pure air, continue to move in the same axial direction towards the narrow hole 4, and clean air exits through slots 2.

Cyclones. They are used for coarse and medium cleaning of dry non-fibrous and non-coalescing dust. Dust separation in cyclones is based on the principle of centrifugal separation. Getting into the cyclone tangentially through the inlet pipe 1 (Fig. 11, d), the air flow acquires a rotational motion in a spiral and, having descended to the bottom of the conical part 2, goes out through the central pipe 3. Under the action of centrifugal forces, dust particles are thrown to the cyclone wall and, carried away by the air flow, sink to the bottom of the cyclone, and from there they are removed to the dust collector. The cleaning efficiency increases (up to 90%) with a decrease in the size of the cyclone, since the magnitude of the centrifugal force is inversely proportional to the distance of dust particles from the axis of the cyclone. Therefore, instead of one large cyclone, two or more smaller cyclones are placed in parallel - the so-called battery cyclones.

Due to the possible ignition and dust explosions in cyclones, they are installed outside the production facilities.

To purify air with a high content of dust, cyclones with a water film created on its inner surface are used.

Rotary dust collectors (rotoclons). These dust collectors are a centrifugal fan (Fig. 11, e), which, simultaneously with the movement of air, cleans it from large dust particles (> 10 μm) due to the forces of inertia arising from the rotation of the impeller.

Dusty air enters the suction hole 1. When the wheel 2 rotates, the dust-air mixture moves along the interblade channels of the wheel, while the dust particles under the action of centrifugal forces and Coriolis forces are pressed against the surface of the wheel disc and against the oncoming sides of the wheel blades. Dust with a very small amount of air (3-5%) enters through the gap 8 between the wheel 2 and the wheel disk into the annular receiver 5, and the purified air enters the volute 4 and the outlet pipe 9. The mixture enriched with dust through the pipe 5 enters the bunker b, in which the dust settles, and the air released from it through the hole 7 again returns to the dust collector 3. In the bin 6, the dust is moistened.

Rotoclons are used in dusty industries such as foundries. They provide a relatively high cleaning efficiency: for dust particles from 8 to 20 microns - 83%, and for larger ones - up to 97%.

Rice. 11. Dust separators: a, b - dust settling chambers; c - louvered dust separator; d - cyclone; e - rotoclone

Filters. Filters are devices in which dusty air is passed through porous, mesh materials, as well as through structures capable of trapping or depositing dust.

Glass wool, gravel, coke, metal shavings, porous paper or cloth, thin metal mesh, porcelain or metal hollow rings are used as filter materials. Depending on the material used, the filters have the appropriate name - cloth, paper, etc.

Paper filters. The filter material in them is corrugated, porous paper (cellulose wadding) or the so-called silk (silky porous paper), folded into 4-10 sheets and placed in special cassettes. Such cassettes are installed in the cells of a metal frame. The cleaning efficiency of paper filters is very high - up to 98-99%. These filters are used to purify the air supplied to the room.

In order for the cassettes to be periodically freed from part of the deposited dust, the filter is shaken.

Fabric filters. On fig. 12a shows a self-shaking bag filter of the FV type with a back-flush. It consists of several sections, each of which contains 18 sleeves with a diameter of 135 mm.

The filter works as follows: dusty air enters housing 2 through pipe 1, which is common to all sleeves, from where it enters sleeves 3, and, passing through the fabric of the latter, leaves dust on its surface. Purified air exits the filter through valve boxes 4.

Periodic shaking of the filter sleeves is performed by mechanism 7, and back blowing is performed by a variable position of valve 8. Dust is removed into dust collector 5 with exhaust valve 6 using screw 9. For fine and almost complete air purification (99.9%), a number of industries use filters made of FPP fabrics.

Oil filters. Such filters are used to purify the air supplied to the premises at low dust concentrations (up to 20 mg/m3).

A number of designs is a cassette covered with mesh and filled with porcelain or copper rings, corrugated meshes (Fig. 12, b). This cassette is dipped in spindle or vaseline oil before being installed in the network.

Dust particles, passing with air through the labyrinth of holes formed by rings or nets, linger on their wetted surface. The cleaning efficiency reaches 95-98%.

Rice. 12. Filters:

a - cloth sleeve self-shaking; b - cassette oil; c - self-cleaning oil

At present, self-cleaning oil filters (Fig. 12, c) are widely used, in which filtration is carried out by two continuously moving cloths 2 made of a metal mesh. The lower part of the web is 150 mm immersed in the oil in bath 1.

If the oil filters are dirty, the rings and meshes are washed in a soda solution.

Electrical filters. Filters are used to clean air and gas from fine dust. The operation of electrostatic precipitators is based on the creation of a strong electric field using a rectified high voltage current (50–100 kV) supplied to the corona electrodes (Fig. 13, a). When dusty gas or air passes through the filter, ionization of dust particles occurs, i.e., the formation of positive and negative ions. The dust that has received a charge from the negative corona electrode tends to settle on the positive electrode, which is the grounded walls of the filter and special collecting electrodes. These electrodes are periodically shaken using a special mechanism, and the settled dust is collected in a hopper, from where it is removed.

ultrasonic filter. In such filters (Fig. 13, b), used for fine cleaning, under the influence of high-intensity ultrasound, coagulation of the smallest dust particles occurs. The resulting large particles are then deposited in conventional dust collectors, such as cyclones.

Rice. 13. Filters:

a - electric; b - ultrasonic; 1 - insulator; 2 - filter walls; 3 - corona electrode; 4 - grounding; 5 - ultrasound generator; 6 - cyclone

The cleaning efficiency is 90% under the action of ultrasound for 3–5 s.

If the required cleaning efficiency is achieved in one dust collector or filter, then such cleaning is called single-stage. With a high initial dust content of the air, two-stage cleaning is used to obtain the required purity. For example, if the first stage of air purification is a cyclone, then a fabric filter can serve as the second stage, etc.

Proper operation of filters (timely cleaning, washing, etc.) is of great importance for the efficient operation of ventilation.

Maud. "UVP-1200A" and mod. "UVP-2000A".

designed to remove and purify air from abrasive, metal, etc. dust, small chips generated during the operation of grinding, grinding and cutting machines, can be used when working on stone and glass. The units carry out two-stage air purification (through a dry cyclone and a block of bag filters). After cleaning, the air is returned to the room. Waste accumulates in a metal box (at the bottom of the unit). Installations for air purification from abrasive dust mod. " " and mod. " " have a manual filter regeneration system (shaking). Design atmachines for cleaning the air from abrasive dust mod. " " and mod. " " provides efficiency in preparing for work without organizing a special place, has wheels and can be easily moved.

Distinctive features:
- in the cold season, warm air remains in the room;
- does not require a specially equipped place;
- efficiency in preparation for work;
- ease of maintenance.

T E H N I C E S K A Y H A R A K T E R I S T I C A UVP-1200A, UVP-2000A

Air productivity, m 3 / h
Created vacuum, Pa
Average median size of trapped particles, µm
Dust collector capacity, m 3
Number of inlet pipes, pcs.
Air duct diameter, mm
The greatest distance from machines, m
Degree of air purification, %
Noise level, dBa
Fan motor power, kW
Dimensions, mm
Weight, kg

FILTROCYCLONE FCC

It is intended for air purification from coarse, medium and finely dispersed dust generated in the following technological processes: grinding, cutting, turning, processing of casting molds, sandblasting and shot blasting, pouring of dusty materials, etc. Small dimensions combined with high performance allow creating on the basis of local dust cleaning systems in close proximity to dust sources.
The use of modern filter materials allows for effective purification of polluted air and the return of purified air back to the working area.