What is the separation principle of bag filter

Bag filter is a new type of filter system, which has the advantages of high filter precision, large processing capacity, low cost, convenient use and maintenance, complete specifications, various materials and wide application range Mainly used in: food, health, pharmaceutical and other industries Bag filter can be divided into single bag type and multi bag type according to the number of bags, and can be divided into side in type and top in type according to the position of feeding hole Now the side in type has been replaced by top in type In addition, according to the requirements of the user's filtration temperature, the sandwich filter can also be provided, which is generally double-layer structure The sandwich can be connected with steam or heat-transfer oil to maintain or improve the temperature of the fluid, prevent the fluid from solidifying, improve the filtration speed of the viscous liquid, or meet the temperature requirements of the next process So, what is the separation principle of bag filter? Let's introduce the following to you from Xiaobian The structure principle of a typical bag filter is shown in the figure below It mainly relies on the dusty air flow through the filter medium to achieve the separation purpose, which is the result of screening, inertial collision, interception, diffusion, electrostatic and other comprehensive effects 1 During screening and filtration, particles with diameter larger than that of filter cloth fiber or between dust on filter cloth are retained When a certain thickness of dust is formed on the surface of the filter cloth, the screening effect will be more significant 2 In the inertial impact effect, the inertia of particles plays a leading role The larger the particle mass and the higher the gas velocity, the stronger the inertial effect 3 Interception when the ratio r of particle size DP to trap size D is large, the interception effect is more prominent In general, direct interception ratio R is used to express interception efficiency 4 Brownian diffusion particle will shake around its shell line and generate Brownian motion When it is close to the surface of the filter cloth, it will be separated by contacting with it When the gas velocity and particle size decrease, the diffusion will increase 5 Electrostatic dust and filter cloth fiber may be charged, causing mutual absorption or repulsion from the surface, affecting the separation efficiency of the bag filter Under the comprehensive influence of the above functions, the dust is gradually collected on the surface of the filter bag, forming the primary layer of dust The primary layer of dust is the main filter layer of the bag filter, which is more important than the filter cloth The primary layer of dust shall not be damaged during dust cleaning, otherwise the dust removal efficiency will be significantly reduced When the dust accumulates on the filter cloth to a certain extent and the filter resistance reaches a certain value, the dust shall be removed in time That's how the bag filter works Do you understand?