Fabric filters resistance factors

Pressure drop— Another factor of major importance in a fabric filter is the pressure drop caused by the combined resistances of the fabric and the accumulated dust layer that builds up on the surface of the fabric. The pressure drop for an operating fabric filter with dust cake accumulated on the fabric can be estimated using the following equation [2,18,41] ... 

The fabric substrate used for the filter media will need to provide certain characteristics, dependent on the application. The typical properties required include abrasion resistance, stretch resistance, dimensional stability, and resistance to flex fatigue. All these performance criteria can be assessed by using suitable test methods. The fabric will also be tested for correct warp and weft sett, air permeability, thickness, density, and fabric tensile properties. All the factors will affect the performance of the filter as they are directly related. If woven fabrics are considered, the porosity will be directly related to the sett and therefore air permeability. The combinations of the fibre types, fabric constructions, and coating substrate will provide the filter manufacturer with a range of properties for use in a range of appUcations. 

Air permeability n. The porosity or the ease with which air passes through material. Air permeabihty determines such factors as the wind resistance of sailcloth, the air resistance of parachute cloth, and the efficacy of various types of air filters. It also influences the warmth or coolness of a fabric. 

Woven wire lends itself easily to fabrication of pressure filter leaves and filter baskets. It is easily applied to filter dmms. It is resistant to blinding and is easily cleaned. Stretching or shrinking is non-existent. It usually costs more than non-metallic media, but usually has a long life which helps to off-set the cost along with the other factors above. 

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