Types of dust collection systems

Depending on physical principle industrial separators are classified into dry mechanical, wet scrubbers, electrical precipitators and bag filters. Figure 3 shows the classification of separators.

Table 3. Classification of separators

Dry mechanical separators

Dry mechanical separators are one of the most widely used dust collectors in industry. This type of device is characterized by its simple design and ease of maintenance and repair. However, when used alone, dry mechanical separators have 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. There are gravitational, inertial and centrifugal dust settling chambers.

In gravitational dust settling chambers, particles are deposited due to gravitational forces (Fig. 1). The advantages of this type of device are ease of manufacture and operation. But the efficiency values ​​of such installations are small, and the space they occupy is significant. That's why this type 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 settling chamber: a - simple camera; b - chamber with partitions; c - multi-shelf chamber; 1 - body; 2 - bunkers; 3 - partition; 4 - shelf

The dust deposition rate of dry mechanical dust collectors is calculated as follows:

Where X h- particle sedimentation speed, m/s; d h - particle diameter, m; sch- particle density, kg/m3; sg- gas density, kg/m3; g- free fall acceleration, m/s 2 ; O h- particle drag coefficient.

The minimum size of dust particles that will be completely deposited by gravity is found using Stokes' law using the following relationship:

Where V G- volumetric gas flow, m 3 /m; m G - dynamic viscosity coefficient, Pa s; B, L- width and length of the chamber, 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 hopper. Unfortunately, the effectiveness of such devices is low. Chambers with smooth rotation have the least hydraulic resistance. With particle sizes of 25-30 microns, the degree of particle capture reaches 65-80%. Figure 2 shows various types dust collectors.

Rice. 4. Inertial dust collectors: a - with a partition; b - with a smooth rotation of the gas flow; c - with an expanding cone; g - with lateral gas supply

One of the most commonly used dust collectors is cyclone dust collectors. Cyclone dust collectors are less commonly used individually due to their low efficiency. Cases of single use of this type of filter are possible if the functionality or reliability of other types of separators is unsatisfactory. The following requirements are imposed on cyclone dust collectors: optimal separation efficiency under variable production parameters, taking into account low maintenance and repair requirements constantly existing installations, resistance to abrasive wear, high temperatures, accumulation of adhering dust, provision of preventive measures against the explosion of flammable dust, small space, etc.

The main geometric characteristic of this type of apparatus is its diameter. With large diameters their throughput decreases. Therefore, cyclones of small diameters (150 - 630 mm) are usually used.

If it is necessary to clean the gas flow with a large throughput A series 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 get more high 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) reliable operation at gas temperatures up to 500 °C; 3) the ability to capture abrasive materials while protecting the internal surfaces of cyclones special coatings; 4) dry dust collection; 5) almost constant hydraulic resistance of the apparatus; 6) successful work at high pressures gases; 7) ease of manufacture; 8) maintaining high fractional cleaning efficiency with increasing dust content of gases. The disadvantages are: 1) high hydraulic resistance: 1250 - 1500 Pa; 2) poor capture of particles of 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; g, d - axial (rosette)

The efficiency of collecting dust particles in a cyclone separator is directly proportional to the gas velocity to the power of S and inversely proportional to the diameter of the apparatus, also to the power of S.

In practice, cylindrical and conical cyclones are most often used. At the same time, cylindrical cyclones are highly productive, and conical ones are highly efficient. The diameter of cylindrical cyclones does not exceed 2000 mm, and the diameter of conical cyclones does not exceed 3000 mm.

The hydraulic resistance of single cyclones is determined by the formula:

Where X G- gas velocity in an arbitrary section of the apparatus, relative to which the value is calculated O ts, m/s; O ts- resistance coefficient, which is determined as follows:

Where K 1 - coefficient correspondingly equal to 16 for cyclones with tangential gas inlet and 7.5 for cyclones with rosette inlet; h 1 , b- dimensions of the inlet pipe, m; D TR- exhaust pipe diameter, m.

The resistance coefficient for group cyclones is calculated using the following relationship:

Where O ts- 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).

Another type of dry dust collectors is vortex dust collectors. Their main difference from the previous type is the presence of an auxiliary swirling gas flow. Fresh gas can be used as a secondary gas flow in vortex dust collectors. atmospheric air. When using dusty gases as a secondary gas, the productivity of the device increases by 40 - 65% without a noticeable decrease in cleaning efficiency. The critical diameter of particles completely captured in the dust collector is determined by formula 15:

Where X G- gas velocity in the free section of the apparatus, m/s; H- height of the dust collection chamber, m; D up- apparatus diameter, m; D tr- diameter of the supply pipe, m; sch- rotation speed, m/s.

Advantages of vortex dust collectors compared to cyclone ones:

• 1) higher efficiency of collecting highly dispersed dust;
• 2) absence abrasive wear internal heating surfaces;
• 3) the possibility of gas purification at more high temperatures through the use of cold gas;
• 4) the ability to regulate the separation process by changing the amount of secondary gas. Disadvantages of this type dust collectors:
• 1) the need to use an additional blowing device;
• 2) increasing the total volume of gases passing through the separator due to secondary air;
• 3) the device is very difficult to operate.

Below are the characteristic parameters of dry mechanical dust collectors.

Table 4. Characteristic parameters of dry mechanical dust collectors

Ventilation dust collection units UVP (Individual chip ejectors UVP-IN series) designed to remove and clean air from shavings and sawdust and collect waste in storage bags. Chip ejectors are designed for use in small enterprises with a small amount of waste generated. The degree of air purification by the installations is 99.9%. The units are used to remove contaminated air from individual machines or groups of machines and have an air capacity of up to 7000 m 3 /hour. Due to the design features, the distance from the machine to the chip ejector, as a rule, should not exceed 2 m. The installation consists of a housing with a built-in dust fan; filters and waste storage devices are attached to the housing using easily removable clamps.

CHARACTERISTICS OF CHIP EXTRACTORS UVP:

Execution options.

• To purify the air from sawdust, shavings, chipboard sawdust, plastics, etc.
• To clean the air from sawdust, dust generated as a result of processing milling machines MDF and similar materials with increased filtering area.
  When using IN series installations to purify air from shavings, sawdust, dust resulting from the processing of MDF, chipboard, fiberboard and other materials in which the proportion of light fine fraction in the waste composition is relatively high, it is recommended to use filters with an increased filtration area. An increase in area is necessary to reduce the gas and dust load on the filter material. This prevents deep penetration dust particles into the material and increases the service life of the filter. The units are intended for indoor use.

Dust collection units are a class of equipment for workshops, industrial enterprises or home use. Depending on the power and modification of the installation, they can solve various tasks, however, their main purpose is to clean the air from solid particles formed during processing various materials, as well as cleaning small industrial waste(shavings, chips, sawdust, dust).

In design and principle of operation, the chip ejector resembles a conventional vacuum cleaner. Inside the device, microparticles of dust and dirt, metal and wood shavings are separated and deposited on the walls of the filter, and the purified air is returned to workroom. At the same time, special filters allow you to capture even the smallest particles of bulk materials (up to 2 microns), which cannot be achieved with a conventional vacuum cleaner.

Compared to traditional systems ventilation chip cleaner has a number of advantages.

• The cost of equipment and its installation is much lower.
• Saving thermal energy as air circulates indoors.
• The same installation can be used in several places.
• The installation is easy to connect and unpretentious in operation.
• Filters air and helps maintain cleanliness in the workplace.

Areas of application

Devices of this type have wide application possibilities:

• removal of bulk waste at enterprises, carpentry and plumbing shops, home workshops;
• cleaning machines from dust, sawdust, shavings and other dust;
• collecting bulk waste into containers;
• air purification in enterprises and workshops.

They can be used in almost all enterprises, except those where there is a danger of spraying toxic substances. It is also prohibited to use the device while sanding wood, as explosive chips will be formed.

Types of equipment, main differences

The store catalog presents several types of equipment.

Dust collection units are standard. Equipment for industrial air purification from solid particles and dust that is not prone to sticking. Also suitable for collecting and disposing of industrial waste. Ventilation units are available dust collection units UVP 1200/7000. The digital designation corresponds to the performance of the device. For example, it can draw in 1,200 m3 of air per hour. The number of air duct hoses and storage tanks (from 1 to 4) depends on the power of the installation.

JET products are collected in a separate catalog and include the following.

• Air filtration system (). Used in all industrial premises where air pollution by solid particles occurs.
• Exhaust unit (). This compact model is suitable for installation in a workshop or for field work. The unit is equipped with a 55-liter filter bag, which means you won’t have to change it too often.
• Exhaust unit cyclone (). It works on the “cyclone” principle. Developed as an addition to woodworking machines. Cyclone dust collectors received this name due to the internal air cleaner “cyclone”. It uses gravity and centrifugal force to purify the air.
• JET chip ejector (). Suitable for home use and carpentry workshops where there is no large accumulation of waste.
• Hood for woodworking machines (). The installation is equipped with two bags for collecting waste and two filters, which allows it to be used in conjunction with powerful woodworking machines, including several at the same time.
• Cyclones dust collectors (,). Powerful devices, designed for industrial use. The design allows you to filter out the smallest solid particles up to 2 microns in size. Also, during filtration, the installation allows you to separate dust and chips. A rigid body with a high level of noise insulation ensures comfort while working indoors. Three phase motor It is quieter than many of its less powerful counterparts. The container for collecting large waste is quite spacious, and its replacement takes only a few seconds. Large shavings can be reused, which is very convenient, since fine dust is collected in a separate bag.

If you do not take special measures to remove mechanical waste and dusty air from working area woodworking machine, the surrounding space soon after the start of work becomes unsuitable for a person not equipped with personal protective equipment to be in it, and is extremely fire hazardous. Dust collection (aspiration) installations aim to clean the atmosphere production premises, make the work of staff comfortable and safe.

AREA OF APPLICATION

Autonomous dust collection (aspiration) devices are used in industrial premises, which are equipped with centralized system air purification and waste removal seems impossible or impractical. Such installations are used mainly in areas for processing wood and similar materials of small enterprises in the furniture, construction and other industries.

DESIGN FEATURES

Structurally, the scheme for cleaning the mixture of air with shavings and sawdust removed from the machining zone by creating a vacuum exhaust fan, 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 bottom part a device that functions as a waste storage device.

A high degree of air purification, reaching 99.9%, makes it possible to free workers from the need to use personal protective devices (respirators, etc.) and reduce the level of fire danger up to the standard level.

The design of most modern woodworking machines provides the possibility of connecting them to a workshop aspiration system or to a dust collection unit.

Dust collecting devices are equipped with one or several filter units, consisting of fabric bags located one above the other: a filter and a storage tank. Depending on the volume of waste emitted by the equipment, you can select an installation of appropriate productivity. As a rule, several emission sources can be connected to one unit.

Many models of dust collection units can be used in vacuum cleaner mode when cleaning a production area.

KEY BENEFITS

Dust collection units have become an essential element of organizing woodworking production. Without such devices it is impossible to fulfill the established sanitary standards requirements for working conditions and ensure compliance with fire safety standards.

Overall dimensions of dust collection units PFC

Payment methods:

• By bank transfer for legal entities with VAT.

Delivery in Moscow and the Moscow region:

• Transport company Business lines or PEC, others by agreement.
• Items “in stock” can be picked up from the warehouse on the day of receipt cash to our bank account.
• Delivery is carried out within 1-2 business days from the moment your order is ready.

Delivery within Russia:

• Transport company (TC) Business lines or PEC, others by agreement. Delivery to the TK terminal is FREE. (3 times a week).
• Delivery costs TK depend on the region. Our managers will calculate all options and offer the most convenient and profitable delivery method for you.
• By our vehicles in the shortest possible time. Delivery costs are calculated based on the volume and weight of the cargo.

Guarantees

• Our company sells exclusively new products, which are covered by a factory warranty from 12 months to 36 months.

PFC dust collection units are designed for fine air purification inside small and medium-sized industrial and agricultural premises. Can be used to clean the air from wood dust and suspended shavings in woodworking industry workshops. The highest dust content in the working environment is 15/5 g/m3. (in the ratio of large suspended fractions / dust).

The minimum air purity at the outlet of the PFC dust collector is 0.5 mg/m3.

Design features

Dust collection units PFC have a mobile design, are produced in the form of a monoblock, and are delivered to the customer assembled in the manufacturer’s packaging.

To the main components of the dust collection unit PFC series The following structural elements include:

The housing is a load-bearing steel element of a welded structure on which the remaining components and parts of the equipment are located. The housing contains a cyclone element, which performs primary gravitational air purification from large suspended particles (the first stage of purification). In the cyclone, the air swirls, due to which the particles, under the influence of centrifugal force, are pressed against the walls of the cyclone and settle in the dust collector.

At the bottom of the case there is a dust collection bag, which is removed as it is filled to clean and dispose of collected dust and debris. In the upper part of the housing there is a cassette filter made of F9 class filter paper, where fine air purification occurs (the second stage of purification). Compared to a filter bag (as, for example, in PUA-M chip ejector dust collectors), a paper cassette filter provides finer cleaning and has a longer service life.

In the basic version, together with the cassette, the unit is equipped with a manual regeneration system inner surface, but at the customer’s request it is possible to retrofit the PFC dust collector with an automatic regeneration system.

The purified air is released directly into the atmosphere of the room. The air is forced to move due to the operation of a low-noise dust fan installed on the housing. The drive used is asynchronous electric motor. The fan inlet has round section and directed downwards (it is possible to connect an air hose or a short air duct).

Manufacturing options

The standard size range of PFC dust installations includes 7 standard models.

Installations for dust and chips PFC-1250, PFC-1500 and PFC-2000 are available in a single version. The remaining models of dust collection units PFC are made in a group design (two cassettes and two dust collectors).

The selection of the required model is carried out according to the rated performance, taking into account the actual operating conditions.

terms of Use

PFC dust collection units are subject to operation indoors under U2 conditions in accordance with GOST 15150.