Introduction to filter bag
The material of dust removal cloth bag is cloth or felt woven from synthetic fiber, natural fiber or glass fiber. The cloth or felt shall be sewn into cylindrical or flat filter bags as required. According to the nature of flue gas, select the filter material suitable for the application conditions. Generally, when the flue gas temperature is lower than 120 ℃ and the filter material is required to have acid resistance and durability, polyester flannelette and polyester needle felt are often selected; Graphite glass fiber cloth is mainly used to treat high-temperature flue gas (<250 ℃); In some special cases, carbon fiber filter materials are selected. It is very important to control the speed of flue gas passing through the filter material (called filtering speed) during the operation of bag filter. Generally, the filtration rate is 0.5-2m/min, and the filtration rate is higher than 0.1 μ The particle efficiency of m can reach more than 99%, and the resistance loss of equipment is about 980-I470Pa.
The bag of the dust remover is made of textile filter cloth and non-woven felt. The filter function of the fiber fabric is used to filter the dust containing gas.
By temperature and material
1、 Normal temperature cloth bags: normal temperature cloth bags are mainly made of polyester, polypropylene, acrylic and other fibers through non-woven and textile processes, with good permeability, smooth surface, good dimensional stability, easy to peel dust and other excellent properties. It is mainly used for dust removal and normal temperature flue gas treatment in industries with dust pollution in general industrial enterprises;
2、 Medium temperature cloth bag: With the improvement of the country's emphasis on environmental protection, especially the rapid development of bag type dust removal technology industry in recent years, China has begun to use imported synthetic fibers to develop high-performance filter materials that can adapt to relatively harsh working conditions and have an ultra long service life. At present, the common medium temperature filter materials include aramid fiber and PPS series fiber, which are treated by dipping, waterproof, oil proof and anti-corrosion processes to achieve ideal results;
3、 High temperature cloth bag: The high temperature cloth bag is mainly made of P84, expanded glass fiber, ultra-fine glass fiber and other high temperature resistant fibers through textile and non-woven processes, with good thermal stability, high filtration efficiency, long service life and other characteristics. It is mainly used for dust removal under various high-temperature flue gas conditions.
The dust removal cloth bag/filter bag is the heart of the bag filter during its operation. Usually, the cylindrical pulse filter bag is vertically suspended in the dust remover. The dusty gas enters the dust remover from the air inlet and passes through the guide plate of the ash hopper, so that part of the large particle dust in the gas is separated by the inertial force and directly falls into the ash hopper The dusty gas enters the filter bag area of the box, and most of the dust is trapped on the outer surface of the filter bag, while the clean gas enters the filter bag through the filter material. The purified gas enters the upper box through the filter bag mouth, and then is discharged from the air outlet The cage inside the filter bag is used to support the filter bag, prevent the filter bag from collapsing, and help to remove and redistribute the dust cake.
The fabric and design of the dust removal bag should strive for efficient filtration, easy dust stripping and durable effect. The selection of dedusting bag is very important, which directly affects the dedusting effect of the deduster. The selection of dedusting bag can be made from the following aspects: gas temperature, humidity and chemistry, particle size, dust concentration, filtering wind speed, dust removal method and other factors.
The dust removal bag is generally divided into pulse type dust removal bag, vibrating type dust removal bag and back blowing type dust removal bag according to different dust removal methods.
According to different shapes, there are also round bag type, flat bag type and envelope type.
There are also different design methods for the opening and bottom of the bag.