Principle of dust Filter

Inertial impaction , interception, diffusion , sedimentation mechanism of gravity and electrostatic dust and other particles in the dust precipitator filtration analysis of the theoretical basis of the mechanism . Precipitator dust filter process is relatively complex , in general, to catch dust particles settling in the collective , that is separated by filtration , sedimentation is not only a filter mechanism at work , but the result of a variety of sedimentation separation filter mechanism joint action . Depending on the mechanical properties of different size dust in a fluid movement , filter dust removal mechanism involves the following aspects: 1.Sieving action Mesh filter media is generally 5 ~ 50μm, when the dust size or larger than the pore diameter of the mesh or dust deposited on the gap between the dust filter between , namely dust resistance stay. For new fabric filter , because the gap between the fibers that is much larger than the pore size of the dust particle size , so screening has little effect , but a lot of dust filter surface deposition after the formation of the dust layer , screening significantly enhanced . 2.Inertia collision Usually the larger particle size of dust rely mainly on the inertia collision trap . When the dust stream close to the filter fibers , the fibers will bypass airflow , where larger particles ( greater than 1μm) due to inertia , departing from the airflow line , continue along the original direction of movement , the impact to the fiber is trap . All large dust particles in the dust within the trajectory of the critical line can reach the surface of the fibers trapped . This inertia collision , with the dust size and air flow rate increases strengthened. Therefore, improving the air flow rate through the filter can be improved inertial collision . 3.Knockdown effect When the dust stream close to the filter fibers, fine dust particles together with the air flow around , if the radius of the dust particles larger than dust particles away from the center to the edge of the fiber , that is due to contact with the fiber dust was blocked . 4.Diffusion For less than 1μm dust particles , especially less than 0.2μm sub-micron particles , molecules in the gas flow line from the impact , like the gas molecules as Brownian motion , and if the fiber contact during exercise , you can from the gas stream separated . This effect is called diffusion , with its velocity decreases, the fiber diameter is reduced and dust is enhanced . 5. Electrostatic interaction Many fiber woven filter, when airflow through , since the friction will produce static phenomenon , but also dust due to friction and other reasons, live in the transportation process , which will be formed between the filter and the dust particles a potential difference , when the dust filter with the airflow tends , due to the Coulomb force to promote fiber filter dust and impact and enhance the suction force of the dust filter and trapped , improve collection efficiency . 6. Gravity sedimentation When the dust stream slowly moving into the dust , particle size and density of large dust particles , it may be due to natural gravity settling down In general , all kinds of dust removal mechanism is not effective at the same time , but a joint or several works . Moreover , the gap with the filter , change of air velocity , the particle size of dust and other reasons , the effects of various different mechanism of filtration properties of the filter media are also different . In fact , at the beginning of the new filter dust , dust removal efficiency is very low. After a period of use , the coarse dust layer of dust will be the primary layer is formed on the surface of the cloth .