Dust collectors fabric filters

Fortress Designs Supplier of dust control equipment, baghouses, dust collectors, fabric filters, dust filters, bin vents. http ll vww. fabricfilters.com... 

Cost of dry, mechanical dust collectors, high-voltage electrostatic precipit ators. and fabric-filter dust collectors. 

A wide variety of woven and felted fabrics are used in fabric filters. Clean felted fabrics are more efficient dust collectors than woven fabrics, but woven materials are capable of giving equal filtration efficiency after a dust layer accumulates on the surface. When a new woven fabric is placed in service, visible penetration of dust may occur until buildup of the cake or dust layer. This normally takes from a few hours to a few days for industrial applications, depending on dust loadings and the nature of the particles. 

Many types of particulate collection devices are available commercially (see Table 53.2). Each operates on a different principle for accomplishing removal of particulates from the gas stream. Four basic types are common in drying systems (1) the drying vessel itself (in the case of vessel dryers), (2) cyclones, (3) bag filters, and (4) wet scrubbers. Electrostatic precipitators (ESPs) are not used widely in drying installations in spite of their low-pressure drop and high collection performance. The initial cost of purchase and construction is high. For this reason, the emphasis in Section 53.3 will be on the three most widely used devices, e.g., cyclones, fabric filters, and wet scrubbers. For a concise discussion of various types of solid-gas separation equipment and guidelines for selection of dust collectors,... 

FIGURE 53.3 Fabric filters (a) large, multicompartment fabric filter cleaned by mechanical shaking. (Courtesy of Wheelabrator-Shint.) (b) Envelope-type fabric filter cleaned by reverse flow. (Courtesy of Shinto Dust Collector.)... 

The actual size of a fabric dust collector will vary according to the volume of dust that has to be removed from a process in a given period of time. The velocity at which the dust is carried into the filter (sometimes referred to as the air-to-cloth ratio) is also a major factor in determining the total fabric surface area requirement. To give the reader some perspective as to the diversity of sizes, a filter may contain just a few sleeves in order to capture a small volume of nuisance dust, from say a woodworking shop, whereas in one of the largest fabric filters in the world, the Eraring Power Station in Australia, some 190 000 sleeves are used, with a total filtration area of over 500 000... 

Because of the wide diversity of thermal and chemical conditions that prevail in dust collectors, the correct choice of fibre type is the most fundamental of all considerations when designing or selecting the filter fabric. A selection of the more common fibre types that are used in dust collection and their properties is shown in Table 7.2. 

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