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Canadian Air Systems Co. is an engineering company of industrial cartridge type dust collectors. Dust collectors are available in numerous designs utilizing a number of principles and featuring wide variation in effectiveness, initial cost, operating and maintenance expense, space, arrangements and material of construction. One of the most efficient dust collectors designs is a cartidge style dust collector. Cartridge dust collector is a self-cleaning dust collector that uses filtering cartridges made out of synthetic fibers and a chemically treated cellulose, which is capable of collecting sub-micron particles without creating an excessive pressure drop in the system. It uses an air-jet cleaning system to maintain high filtration efficiency with a constant pressure drop, and doesn't need a system shutdown to clean the filter cartridges. The filtration velocities in cartridge dust collectors allow the use of more compact units, reducing installation and maintenance cost. In this type dust collector the dust laden air comes in the side of dust collector hopper, under vacuum or pressure, and filters through the cartridges exiting through venturis into the clean air plenum. The clened air then can be exhausted outside or recirculated. For each row of filtration cartridges, there is a diaphragm valve, connected to an air tank which is opened in sequence by a solenoid valve with electronic controller. Short pulses of compressed air are ejected through calibrated orifices in the blow tubes, into the venturi, creating a pressure wave along the cartridge - to break the accumulated dust cake in the filter media. The elctronic controller allows compressed air only to one row of cartridges at any given moment, so that dust collector can operate continually. The cleaning cycle is also initiated by monitoring differential pressure across the tube sheet that separates the plenums. As the dust accumulates on the surface of the filter, the differential pressure across the media increases. At a certain value, the solenoid is triggered and cleaning happens. Triggering the cleaning cycle at a predetrmined differential pressure setting eliminates cleaning during periods of light dust load, increases bag life, and reduces the use of compressed air. The maintenance of cartridge dust collector is limited to an annual replacement of the set of cartridges. Filter material is selected based on the operating temperatures, type and size of duct particles, dust collector capacity. At ambient temperature, majority of pulse-cleaning collectors use 10 to 14-oz polyester felt media. Synthetic materials have better temperature resistance than natural materials. At elevated temperatures up to 500 F, fiberglass bags can be used. Nomex is well suited to the 250 to 400 F range. Surface finish of the bag enhances release of sticky dusts. Applying a silicon finish layer to the bag is commonly used. Special coatings provide a membrane with tiny perforations that achieve very high filtration efficiencies. Pleated filter elements allow for more surface area and are often retrofitted into the system. The following factors determine the size of cartridge dust collector: * Concentration and particle size of contaminant; * Degree of collection required; * Characteristics of air or gas stream; * Characteristics of contaminant; * Methods of disposal. For abrasive or corrosive applications, special cmaterials of construction are available, such as abrasion resistant carbon steel, stainless steel, special alloys, rubber liners, etc... Many sizes and arrangements of cartridge dust collectors are available from Canadian Air Systems to meet specific capacities and space requirements. For additional information please refer to http://nis-co.com/dustcollector/Index.html. Oleg Tchetchel, Ph.D Canadian Air Systems http://nis-co.com/index.html http://nis-co.com/dustcollection/Index.html
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