The bag filter is a “dry” type dust collector. It is used to purify dust-gas-air compositions and has a high degree of efficiency. In terms of processing quality, it is noticeably superior to wet cleaning equipment and electrostatic precipitators. The device is equipped with filter elements operated at high temperatures and made of materials such as polyamide and polytetrafluoroethylene.
Description
The bag filter belongs to the category of universal equipment, as it can be used with the same efficiency in most of the processes characterized by a large amount of generated dust. It does not require constant monitoring and maintenance, and the operation is continuous.
It is also worth noting the possibility of manufacturing devices with different sizes, design featuresand identical characteristics suitable for operating conditions. Depending on the restrictions and dimensions of the installation site, the design of products can be selected or developed individually.
Characteristics of dusting compositions determine the type of material treatment, which can be, for example, oil-repellent or antistatic, as well as the structure itself. To make the right choice, dust analysis is often carried out in special laboratories.
Application
The scope of use of the equipment is quite extensive, the bag filter provides cleaning of aspiration emissions and flue gases in various industries, such as:
- production of building materials;
- non-ferrous and ferrous metallurgy;
- foundry;
- automotive industry;
- energy and mining;
- food production;
- metalworking;
- furniture, glass and chemical industries.
Calculation of bag filter
Installation may have a different area of the filter material, the determining factor is the pressure drops attributable to the fabric. Other main criteria should also be taken into account, these include the following:
- dew point temperature;
- moisture level;
- pressure and temperature indicators;
- properties of gases;
- volume of medium to be cleaned;
- explosiveness of gases;
- output concentrationdust and its type;
- technological process parameters;
- presence of toxic substances in the composition.
To calculate the bag filter, you need to set the flow rate of purge gas and dusty compositions per material. The filtration rate of the type of fabric used must also be taken into account.
Sleeve
The filtering element of the equipment is a sleeve made of needle-punched non-woven fabric. There are two basic designs:
- elliptical, placed both vertically and horizontally;
- round, suitable for vertical use only.
The average service life of hoses is about 3 years, in some cases they can be used for more than 7 years. Despite this, the efficiency of the equipment directly depends on the regular replacement of the sleeves. The use of modern fabrics that reduce residual dust is also recommended.
Regeneration system
Regeneration of bag filters ensures their functioning and offline operation. Several regeneration systems are used, the impulse variety is considered the most effective and reliable. It is carried out using compressed air, which is previously cleaned of dust and oil pollution, with a pressure of not more than 0.6 MPa. This process does not require stopping the working cycle and is performed automatically. Two basic regeneration modes are used for the production of filters, eachof which is selected depending on the operating conditions:
- Standard, in which regeneration and gas purification occur simultaneously.
- Mode for difficult applications. It is carried out after turning off one of the sections of the functioning device. The bag filter FR in this embodiment can be completely disconnected from each of the sections on either side, which simplifies the replacement of filter elements and maintenance work on operating equipment.
Switching on of impulse regeneration is possible by timer and diaphanometer. Devices with this mode make up the majority of the market. It is also possible to manufacture equipment according to the specifics of the production, for example, products with mechanical shaking and backflushing.
Views
There are many types of filters, it is worth noting the most common ones:
- pressure;
- Horizontal sleeves (side service;
- bag filter for gas cleaning with vertical placement of the sleeve;
- cyclone devices are equipped with a louvered separator for pre-cleaning and are available in a round body;
- point equipment used to aspirate feed bins and conveyors;
- explosion-proof bag filter;
- high performance devices suitable for high gas volume and low levelresidual dust;
- compact equipment equipped with corrugated sleeves.
Exploitation in difficult conditions
Sleeve filter, the characteristics of which are selected according to the conditions of use, suitable for outdoor and indoor work. In the first option, an addition is required in the form of the following components:
- thermal insulation of the body part, which is of particular importance in the case of vapor condensation;
- heating equipment bunkers and regeneration systems;
- special weatherproof cover.
Among the main types of devices, it is worth noting a two-row design, in the middle part of which there are nozzles for the inlet of contaminated and purified gas, as well as a single-row one, in which the nozzles are located on the side of the structure.
Transportation of equipment is carried out by trucks. To simplify this process, the bag filter, the drawing of which is presented above, is implemented in a partially disassembled form. Knots are manufactured in various variations in accordance with the operating conditions. For the assembly of the structure, a welded method and bolted connections are used. Most devices are designed to operate with excessive vacuum or pressure.
Increase efficiency
In some cases, there is a lack of performance despite compliance with the selection conditionsmaterial and competent calculation. Improving the result is possible by intensifying the method of regeneration, but this contributes to an increase in costs due to a decrease in the period of operation of the matter, which has strong mechanical loads. It is also possible to reduce the filtration rate and increase the layer of accumulated dust, in which case the dimensions of the equipment increase. The bag filter design often includes additional sections that provide continuous operation and the ability to carry out repairs without stopping the device.
