The dust removal method of the bag filter is another important factor in selecting the filter structure type. Different bag filter types with different cleaning methods should use different structural filter materials due to different cleaning energy and deformation characteristics of the filter bag.
(1) The mechanical vibration type bag filter is a bag filter that uses a mechanical device (including manual, electromagnetic vibration, and pneumatic) to cause the filter bag to vibrate and dust. This type of dust collector is characterized by less kinetic energy applied to the dust layer and more times. Should choose to use chemical fiber satin or twill fabric, thickness 0.3 ~ 0.7mm, mass per unit area of 300 ~ 350g/m. The filtration speed is 0.6-1.0m/min; for small units it can be increased to 1.0-1.5m/min.
(2) The sub-room counter-blowing bag type dust collector adopts a sub-compartment structure and uses a valve to switch from room to room to form a counter-blowing air in a reverse direction, so that the filter bag shrinks or swells and removes baghouse dust remover. It has two-state and three-state distinctions, cleaning times 3 to 5 times / h, cleaning power comes from the dust collector body pressure, only in the special site in the back with anti-blowing power; belong to the type of low kinetic energy cleaning.
Chamber-reverse-blown bag filter is divided into inner filter and outer filter, and there is no difference in the selection of filter media. For large and medium-sized dust collectors commonly used round bags, no dust skeleton; length and diameter ratio of the filter bag (1 5 ~ 40): 1; preferred satin (or twill) woven filter; in special occasions can also choose the base cloth The reinforced thin needle felt filter material has a mass of 1.0 to 1.5 mm per unit area of 300 to 400 g/m. For small dust collectors commonly used flat bags, diamond bags or honeycomb bags, must be supported with a dust skeleton, preferred wear resistance, permeability thin thin needle felt filter material, mass per unit area 350 ~ 400g/m.
(3) Vibrating back-flushing and bag-type dust collectors refer to bag dust collectors that have the dual action of vibration and reverse air flow. The vibration causes the dust cake to loosen, and the counter-air current causes the dust to separate. The two methods cooperate with each other to improve the cleaning effect, and is particularly suitable for fine-grained viscous dust. The principle of filter material selection for such dust collectors is generally the same as that of chamber-type back-flushing dust collectors, and satin (or twill) woven filter materials are mainly used.
(4) The nozzle back blowing bag type dust collector uses the blower to do the reverse cleaning power. When the dust filter is in the filtering state, the filter bag is blown in sequence by moving the nozzle to form a strong reverse air flow. Baghouse dust collector for filter bag cleaning is a type of medium kinetic energy cleaning.
For dust with strong abrasion, the following three points should be taken into consideration when selecting the filter media.
(1)Chemical fiber is superior to glass fiber. Expanded glass fiber is better than general glass fiber. Fine, short, and crimped fibers are superior to coarse, long, and smooth fibers.
(2)In the felt, it is better to use acupuncture to strengthen the interlacing between the fibers. The satin fabric in the fabric is optimal, and the brushing on the surface of the fabric is also a measure to improve the abrasion resistance, but the felt, satin fabric and fleece The filter will increase the resistance value.
(3)For the ordinary filter surface coating, calendering and other post-treatment can also improve the wear resistance. For glass fiber filter, silicone oil, graphite, polytetrafluoroethylene resin treatment can improve wear resistance, folding resistance. However, when the coated filter media is used in a condition with strong abrasion, the film will be prematurely worn and the film will be lost.