Flue gas and dust penetrate through the surface of the filter cloth, while in some way to remove the dust, Filter Cloth the two effects of the balance, the filter cloth in the inner layer (felt layer) to form a thickness of 0.5-0.7mm , Which is a layer of dust and filter cloth fibers, which is called an inner filter layer, Filter Cloth which corresponds to the primary filter layer of the plain weave fabric.
In the filtration mechanism of filter fiber, Filter Cloth such as diffusion, gravity, inertia collision, electrostatic and other effects on the dust layer is present, but the main screening effect. When the bag filter begins to run, there is no dust on the new filter bag, and after a few minutes of operation, a thin dust film is formed on the bag surface. As the filter bag is made of fiber weaving, Filter Cloth so the dust layer is not formed before the dust will be in the role of diffusion and other effects gradually formed in the fiber between the fiber bridge phenomenon. Filter bag fiber diameter is generally 20 to 1005m. Needle felt fiber diameter of 10-205m. The distance between the fibers is mostly 10-305m, the bridge phenomenon is easy to occur. Bridge after the completion of the phenomenon of 0.3-0.5mm dust layer is often referred to as dust or a dust layer. In a dust layer above the accumulation of dust again said secondary dust layer.
Plain fabric filter cloth itself dust removal efficiency of 85% to 90%, Filter Cloth the efficiency is relatively low. But the surface of the surface pouring dust accumulation, can get more than 99.5% high dust removal efficiency. It is necessary to remove the dust, the filter cloth surface residual 0.3-0.5mm thick dust layer to prevent the dust removal efficiency. The question is how the dust collector is finished during the operation of the dust collector, and only the second dust layer is removed. This problem is both a technical problem and a disposal experience for the design and manufacturing plant. So you can say that the history of bag filter, is the gradual improvement of the history of continuous improvement. Based on the effect of the dust layer on the efficiency, the dust removal efficiency in the dust layer is drastically decreased. At the same time, the flue gas flows in this part due to the decrease of the pressure loss. Therefore, after a few seconds the surface of the filter cloth and the formation of a dust layer, Filter Cloth dust removal efficiency has increased, that is, each removal cycle can discharge a certain amount of dust.
On the other hand, if the filter wind speed is properly designed, Filter Cloth to the filter cloth surface filter layer has a certain pressure loss (often 1000 a 1500Pa), that is, in the required time to reach a certain thickness of the filter layer, the time is proportional to the wind speed The Take the filter speed of n times, the required time is 1 / n, the number of times the dust layer must be removed at least n times per hour, in fact, Filter Cloth must take into account the time required to clear (10 a 30s), should take n ten times. In addition, Filter Cloth the use of non-woven needle felt as a filter cloth, generally can be used 1.5 to 2.5mm thickness, Filter Cloth this layer is equivalent to the previously mentioned and a dust layer, Filter Cloth it exists in the filter cloth inner layer.
Based on the formation of dust layer is conducive to the theory of filtration, artificially in the ordinary filter surface covered with a layer of microporous film to improve the dust removal effect. Filter Cloth So the membrane surface of the film, also known as artificial dust layer. In order to control the capture efficiency of different particles, the pore size of the microporous surface films of different uses is changed. For example,Filter Cloth when filtering ordinary dust, the pore size is usually less than 25m;Filter Cloth when filtering bacteria, the pore size is less than 0.35m; when the virus is filtered, the pore size is less than 0.055m. Filter Cloth This difference is like a sieve, according to the screen sieve under the requirements of the selection of different sieve screen.