In the process of manufacturing various furniture products, a significant amount of fine dust and particles of the original blanks is produced. Such dust not only worsens the working conditions of production personnel, but also contributes to possible failures of moving equipment parts. That is why in the mass processes of woodworking, the presence of dust collecting installations is provided.
The systems under consideration perform the function of collecting and removing dust and small industrial waste, which contains such unsafe components as resins, alkaloids, toxic organic and inorganic particles. When inhaled as dust, they can cause a wide range of allergic reactions, skin problems and respiratory problems. Often used in woodworking, plywood, MDF and chipboard are especially problematic due to the adhesive resins required to make them. The sequence of action of modern dust collectors ventilation units consists of the following stages:
To implement the set tasks, the dust collection unit includes a duct system, a set of coarse and fine filters, supply and exhaust fans, containers for waste collection. The corresponding areas are necessarily provided for in the design of production sites, and the balance of energy costs includes the consumption of electricity to drive the moving parts of the equipment under consideration.
In order to reduce the noise level, the installation of motors and prefabricated units is usually carried out outside the production area. At the same time, it simplifies access for cleaning and maintenance of all components of dust extraction ventilation units.
The initial indicators for the selection of the standard size and capacity of the dust collection unit are:
To remove finely dispersed wood dust in the branches for adequate dust extraction into the main air duct, a capacity of at least 110 ... 130 m3 / min is usually required. Depending on how many units production equipment connected to the system and how long the ducts are, one or more ventilation units may be required.
In accordance with the hygiene standards established by Rospotrebnadzor (GN 2.1.6.1125-2002), the MPC for dust in woodworking areas is 0.5 mg / m3, while the MPC for harmful components should not exceed 30% of the specified norm. Correct installation and grounding of the collection system (and especially the operation of air ducts) is important to prevent the accumulation of static electricity and developing levels of negative pressure delivered by ventilation air.
The choice of the type, number and performance of the filters is decisive. Modern filtration units contain washable pre-filters. They capture dust particles as small as 3 microns (smaller particles are captured by smoke filters).
There is a disposable bag inside the filtration unit, the dimensions of which depend on the performance of the unit. In woodworking industries, it is recommended to install combined filters that allow you to clean the air, both in the area of the machine's operation and in the general room.
Some of the dust extraction ventilation units are supplied with local work lighting, which makes them good choice for installation directly at the technological equipment. Preference is given to equipment that comes with a remote control.
The main requirement for a ventilation unit is the ability to trap toxic aerosols, fog, gases, vapors, smoke and dust while effectively filtering the air entering the air ducts.
MDM-TECHNO company offers services of design, delivery, installation supervision and field supervision over the operation of dust collecting plants. Upon the conclusion of the contract, qualified specialists of the company will carry out a technical justification of the project, select the appropriate equipment, install and connect it with high quality. Customers are provided with a quality certificate. Post-warranty service of equipment is possible.
Aspiration is a process in rooms with high dust content. Such areas are equipped with special filtration equipment. In particular, are used. The premises of various enterprises are equipped with such equipment: from factories for the industrial production of bricks to grain processing plants. Consider further what are dust collecting installations (UVP).
Dust collecting (UVP) is equipment designed for air filtration. The separation of impurities is carried out in special filters.
Depending on the mechanism of action, these elements are divided into:
Depending on the degree of filtration, the installations can be:
Depending on the areas of application, the devices are divided into 2 categories. The first includes units used to filter ventilation and industrial emissions into the atmosphere, the second includes devices designed to clean flow streams, as well as air masses returned to the workshop during recirculation. Enterprises can use different dust collection plants at the same time. The price of the equipment ranges from 36 to 400 thousand rubles.
According to them, it is determined how effective it is at a particular enterprise. Key technical and economic indicators include:
The simplest is considered, the mechanism of action of which is based on the force of gravity. As a rule, coarse filtration is carried out in it. Particle collection efficiency is no more than 50%. In this case, elements larger than 50 microns are absorbed. Cyclone is more efficient. In it, filtration is based on the use of centrifugal force. In the process of rotation, particles of substances are thrown to the walls of the unit, and then crumble into a special bunker. The cleaned air, rotating, leaves the installation through the pipe. The filtration efficiency of cyclones is 80-90% today.
Currently, such units have the most different design... If it is necessary to clean a large volume of air flow, several devices are combined into groups or battery cyclones are used. They are presented in the form of a large number of small units installed in one housing and located on one bunker. The most popular today, however, are wet dust collectors. Due to contact with a liquid medium, the particles are wetted and enlarged, and then removed from the apparatus in the form of sludge. Such units can have a very different design. For example, it can be rotocyclones, disintegrators, and so on.
Foam units also belong to the class of wet installations. They supply water to a perforated grid. Filtered air also passes through it. There is a threshold on the grate (drain baffle). It allows you to maintain a certain thickness of the foam layer. This is characterized by high efficiency - up to 99%. The unit is capable of filtering particles larger than 15 microns. The industry produces devices PGP-LTI and PGS-LTI with a capacity of 3-50 thousand m3 / h.
Foam includes:
Has the following construction:
The electrostatic precipitator consists of:
Sleeve mouth dust extraction unit filters the air through the fabric. It is sewn together in a special way and placed in a sealed body of the device. The air being purified is sucked out of the filter by the fan and discharged into the atmosphere. The sleeves are periodically cleaned using a backflush shaking mechanism. Filters can be of pressure type and suction type. For their manufacture, a dense synthetic or natural fabric is used. The efficiency of the sleeves is 95-99%. In practice, the most common are the filters FTNS, FRM, FVK.
Electric devices are widely used in the treatment of industrial and ventilation emissions. The mechanism of their operation is based on the following: when gas passes between two differently charged plates, ionization occurs air environment... Ions and dust particles collide, the latter receive electrical charges. Under their influence, they begin to move to the electrodes of the opposite sign and settle there. The filtration efficiency in such devices is 99.9%. Electrical installations are considered economical to operate. They can filter streams at temperatures up to 450 degrees. However, electrical installations must not be used to trap explosive particles.
This process involves not only the elimination of dust from the air, but also its additional purification. The system functions in such a way that it prevents the accumulation of particles and the creation of "traffic jams". This ensures uninterrupted operation of personnel and equipment in the premises. Taking into account the huge volume of waste in industrial enterprises, we can conclude that aspiration is becoming even more in demand due to the established norms of labor protection and safety when personnel work in hazardous conditions.
This method differs from other methods of cleaning indoor air in that the systems are located at a certain angle. This prevents the formation of stagnant zones and localizes areas of maximum release of contaminants. As a result, filtering is implemented. At the same time, the concentration of harmful compounds does not go beyond the permissible limits.
They are used not only at enterprises of the chemical and metallurgical industries, but also in woodworking, grinding and crushing shops. Installation of filtering equipment in such premises requires special knowledge, therefore professionals are invited to install it. The design of an aspiration system begins with an examination of the premises. Based on it, a preliminary calculation of the power and dimensions of the equipment is drawn up. V furniture production there is a huge amount of fine waste. They must be removed from the workspace without fail. For this, a chip suction system is used. The equipment is considered a type of aspiration apparatus.
The chip extractor can remove particles up to 5 µm in diameter. The cyclone of the equipment contains a special fan and filtered bags. The separate machine is connected to the chip suction unit using a flexible duct system made of reinforced or corrugated pipe. The principle of operation is quite simple. The fan draws in polluted air, which is filtered. Dust particles are collected in a bag. From there they are sent to a special filter for final cleaning. When full, the bag is removed and cleaned or replaced with a new one. The chip extractors are easy to connect and transport.
The devices must function smoothly, reliably, with indicators corresponding to the design ones or obtained in the course of commissioning activities and agreed with the developer. Installations for gas purification should be equipped with auxiliary devices and equipment. When using such units, the responsible persons keep the documentation. It reflects the main indicators by which the operating mode of the equipment is characterized. In particular, we are talking about a deviation from the optimal scheme of work, identified malfunctions, failure of individual devices or the entire complex as a whole, etc. All units must be registered with the State Inspectorate for Gas Cleaning. Inspection of the units should be carried out at least once every six months to assess the technical condition. This procedure is performed by a commission appointed by the head of the enterprise.
It is not allowed to use technological equipment with the filtering devices turned off. In each case the cleaning device is turned off while the machine is operating, the organization's management is obliged to notify the State Inspectorate. In this case, it is necessary to obtain a permit for the release approved by the supervisory authorities.
When operating dust-collecting installations for filtering gas with an increased content of explosive (combustible) elements, it is necessary to especially carefully maintain the specified pressure and tightness of structures, correct blowing of devices and communications to prevent ignition and explosion.
On the website Stankoff.RU you can buy dust collecting devices and installations of the world's leading manufacturers. In stock and on order more than 50 models of dust collecting plants according to best prices... Only great deals with detailed descriptions and photo.
Cleaning the air in industrial premises from gases, abrasive dust, metal and wood shavings is necessary not only to comply with sanitary requirements. The presence of air impurities has negative impact on the health of employees, leads to a decrease in efficiency and the appearance of occupational diseases. The funds spent on the dust collection unit are compensated for by a healthy workshop or workshop atmosphere, good performance and equipment safety, which often fails due to clogging of mechanisms with fine particles.
The equipment with dust collection devices presented in our catalog is necessary condition for industrial production associated with the use of wood processing equipment. The technical processes leading to the accumulation and dispersal of dust include operations related to:
A special vacuum cleaner for shavings is installed when filtering air near one machine or is located in an accessible proximity to a group of equipment. For collecting waste, fabric accumulators are used, into which dust gets under the influence of the air flow produced by the fan. Lighter particles settle on the surface of the fabric, while coarse particles accumulate in the dust collector.
The need to buy a chip sucker exists at enterprises whose activities are related to the processing of expensive materials. Simultaneously with air purification, the equipment allows the collection of waste that is returned to the production process. In this case, the dust collection system ensures an economical consumption of raw materials and increases the profitability of production.
The efficiency of the chip suction is determined by the size and composition of the dust particles. With a nominal diameter of inclusions not exceeding 5 microns, the device provides filtration with a degree of 83%, and with a particle size of 20 microns, the purification quality reaches almost 100%. In order to obtain a better result when processing air flow with finely dispersed contaminants, special electrostatic filters are used.
The principle of operation of industrial dust collectors from the catalog of our website is based on changing the direction of movement of suspended particles when they enter the working chamber of the device. Under the influence of inertia, contaminants with a larger mass pass through the dust outlet and settle in the lower part of the filtration chamber. The cleaned air flow is discharged to the outside or re-processed using other equipment.
If high-quality cleaning of a large volume of air mass is required, the operation of several dust collectors is used. The equipment installed in parallel effectively copes with filtration, removing not only accumulations of suspended particles, but also gases with a high temperature and the presence of aggressive substances in the composition.
Industrial dust collectors of standard design are available in varieties that allow you to select the unit with the optimal parameters for removing dust particles with a large or small fraction. In addition to universal models, there are specialized types of equipment that make it possible to clean abrasive dust during the operation of grinding and sharpening machines.
Depending on the technological device, the dust collection systems that we offer in our store remove contaminants from the air stream using different methods:
Wet cleaning technology makes it possible to remove contaminants in a vapor or gaseous state. The work of the structure is based on the use of a water filter and an irrigation system. The mass of moistened suspended particles increases and, under the influence of gravity, the contaminants fall into the lower part of the receiving hopper. The advantages of a wet dust removal system are high efficiency when working with finely dispersed contaminants, but the devices are more expensive to operate, susceptible to clogging and poorly resist corrosion when filtering corrosive gases.
The cyclone dust collector is one of the most common types of devices that use the dry method for air purification. Suspended particles are removed using centrifugal force or gravity. When contaminated air enters the inlet branch pipe of the unit, the flow begins to rotate under the inertial influence. Small inclusions settle on the inner walls and fall into the receiving device of the dust collector. The cleaned air is discharged to the surrounding area through the exhaust pipe.
The choice of a dust collection unit among the 50 models presented on our website is based on the amount of waste that is generated in the room over a unit of time and the aerodynamic characteristics of the production equipment. The dust collection method entirely depends on the physical and chemical characteristics of contaminants, in the analysis of which the most rational cleaning system is selected. It is necessary to take into account the specifics of working operations and select an apparatus with certain technical characteristics for installation in milling or grinding areas. With an optimal combination of suction speed and inlet diameter, efficient operation of the dust collector will be ensured.
If you do not take special measures to remove mechanical waste and dusty air from the working area of the woodworking machine, the surrounding space soon after starting work becomes unsuitable for a person not equipped with personal protective equipment, and extremely fire hazardous. Dust collecting (aspiration) installations are aimed at purifying the atmosphere industrial premises, to make the work of staff comfortable and safe.
APPLICATION AREA
Autonomous dust-collecting (aspiration) devices are used in production facilities, which are impossible or impractical to equip with a centralized air purification and waste removal system. Such installations are mainly used in areas for the processing of wood and similar materials of small enterprises in the furniture, construction and other industries.
Structurally, the scheme for cleaning a mixture of air with shavings and sawdust, removed from the machining zone by an exhaust fan creating a vacuum, is its filtration by passing it through a layer of fabric from which the receiving container is made. The solid component of the mixture separated by the filter is deposited in the lower part of the device, which acts as a waste accumulator.
A high degree of air purification, reaching 99.9%, frees workers from the need to use personal protective devices (respirators, etc.) and reduces the level of fire hazard to the normative level.
The design of most modern woodworking machines provides for the possibility of connecting them to a workshop aspiration system or to a dust collection unit.
Dust collecting devices are equipped with both one and several filtering units, consisting of fabric bags located one above the other: filter and storage. Depending on the volume of waste generated by the equipment, you can select an installation of the appropriate capacity. As a rule, several emission sources can be connected to one unit.
Many models of dust collection units can be used in vacuum mode when cleaning a production area.
Dust collection plants for steel required element organization of woodworking production. Without such devices, it is impossible to fulfill the requirements for working conditions established by sanitary standards and to ensure compliance with fire safety standards.
Depending on the physical principle of operation, industrial separators are classified into dry mechanical, wet scrubbers, electric precipitators and bag filters. Figure 3 shows the classification of separators.
Table 3. Classification of separators
Dry mechanical separators are one of the most widely used dust collectors in the industry. This type of apparatus is distinguished by its simplicity of design and ease of maintenance and repair. However, in the case of a single application, dry mechanical separators have a low final efficiency. Therefore, the most common is a combination of a number of separator types or as multi-stage separators.
Dry mechanical separators are classified according to the type of aeromechanical forces involved. Distinguish between gravity, inertial and centrifugal dust collection chambers.
In gravitational dust-collecting chambers, the sedimentation of particles occurs due to the forces of gravity (Fig. 1). The advantages of this type of apparatus are ease of manufacture and operation. But the values of the efficiency of such installations are small, and the space they occupy is significant. That's why given view dust collectors are rarely used, except in cases in which they are pre-collectors for other separators, i.e. perform a pre-cleaning function.
Rice. 3. Dust collection chamber: a - simplest camera; b - a chamber with partitions; c - multi-shelf chamber; 1 - case; 2 - bunkers; 3 - partition; 4 - shelf
The dust settling rate of dry mechanical dust collectors is calculated as follows:
where NS h- particle sedimentation rate, m / s; d h - particle diameter, m; mid- particle density, kg / m 3; cr- gas density, kg / m 3; g- acceleration of gravity, m / s 2; O h is the particle drag coefficient.
The minimum size of dust particles that will be completely deposited by gravity is found using Stokes's law using the following relationship:
where V G- volumetric flow rate of gases, m 3 / m; m G - dynamic coefficient of viscosity, Pa · s; B, L- chamber width and length, m.
The next type of dry dust collectors are inertial dust collectors. In these types of devices, dust particles under the influence of inertial force will move in the same direction and, after a sharp turn, fall into the bunker. Unfortunately, the effectiveness of such devices is low. The chambers with smooth rotation have the lowest hydraulic resistance. With a particle size of 25 - 30 microns, the degree of particle capture reaches 65 - 80%. Figure 2 shows different kinds dust collectors.
Rice. 4. Inertial dust collectors: a - with a partition; b - with a smooth turn of the gas flow; c - with an expanding cone; d - with side gas supply
One of the most commonly used dust collectors are cyclone dust collectors. Cyclone dust collectors are less often used separately due to their low efficiency. Cases of single use of this type of filters are possible with unsatisfactory functionality or reliability of other types of separators. The following requirements are imposed on cyclone dust collectors: optimal separation efficiency with variable production parameters, taking into account the low requirements for maintenance and repair of permanent installations, resistance to abrasive wear, high temperatures, accumulation of adhering dust, provision of preventive measures against the explosion of flammable dust, small space and dr.
The main geometric characteristic of this type of apparatus is their diameter. With large diameters, their throughput decreases. Therefore, cyclones of small diameters (150 - 630 mm) are usually used.
If it is necessary to purify a gas stream with a large throughput, a number of parallel-installed cyclones with a diameter of 475 - 2500 mm are used.
To determine the separation efficiency in cyclone separators, the total separation efficiency obtained on the basis of experimental data is calculated. This calculation gives the most accurate result. To obtain higher efficiency, small diameter separators are grouped into blocks consisting of 2 to 12 separate cyclones.
The main advantages of cyclone devices are: 1) the absence of moving parts in the device; 2) reliability of operation at gas temperatures up to 500 ° С; 3) the ability to trap abrasive materials while protecting the inner surfaces of cyclones with special coatings; 4) trapping dust in dry form; 5) almost constant hydraulic resistance of the apparatus; 6) successful work with high pressures gases; 7) ease of manufacture; 8) maintaining a high fractional cleaning efficiency while increasing the dust content of gases. The disadvantages are: 1) high hydraulic resistance: 1250 - 1500 Pa; 2) poor collection of particles by size< 5 мкм ; 3) невозможность использования для очистки газов от липких загрязнений.
The main types of cyclones are shown in Fig. 3:
Rice. 5. The main types of cyclones (for gas supply): a - spiral; b - tangential; c - helical; d, e - axial (rosette)
The efficiency of collecting dust particles in a cyclone separator is directly proportional to the gas velocity in the power of Ѕ and inversely proportional to the diameter of the apparatus also in the power of Ѕ.
In practice, cylindrical and conical cyclones are most often used. At the same time, cylindrical cyclones are highly efficient, and conical cyclones are highly efficient. The diameter of cylindrical cyclones is not more than 2000 mm, and the diameter of conical cyclones is not more than 3000 mm.
The hydraulic resistance of single cyclones is determined by the formula:
where NS G is the velocity of gases in an arbitrary section of the apparatus, relative to which the value is calculated O c, m / s; O c- coefficient of resistance, which is determined as follows:
where K 1 - coefficient, respectively equal to 16 for cyclones with tangential gas inlet and 7.5 - for cyclones with outlet inlet; h 1 , b- dimensions of the inlet pipe, m; D TR- exhaust pipe diameter, m
The drag coefficient for group cyclones is calculated according to the following relationship:
where O c- coefficient of hydraulic resistance of a single cyclone; D TR- coefficient taking into account additional pressure losses associated with the arrangement of cyclones in a group (tabular value).
Vortex dust collectors are another type of dry dust collectors. Their main difference from the previous type is the presence of an auxiliary swirling gas flow. Fresh atmospheric air can be used as a secondary gas flow in vortex dust collectors. When dusty gases are used as a secondary gas, the productivity of the apparatus increases by 40 - 65% without a noticeable decrease in the cleaning efficiency. The critical diameter of particles completely captured in the dust collector is determined by the formula 15:
where NS G- gas velocity in the free section of the apparatus, m / s; H- height of the dust collection chamber, m; D an- device diameter, m; D tr- diameter of the supply pipe, m; SCH- rotation speed, m / s.
The advantages of vortex dust collectors in comparison with cyclone:
Below are the typical parameters of dry mechanical dust extractors.
Table 4. Typical parameters of dry mechanical dust collectors
