• According to the temperature of the intake dust gas and the continuous working temperature of the nonwoven filter fabrics in the dry state, the needle felt filter fabrics are divided into three categories: for below 130℃ of normal temperature filter fabrics, for above 200℃ of high-temperature filter materials, and filter media for medium temperature between 130 ~ 200℃.
• According to the humidity of dusty gas, when the vapor volume in the dusty gas above 8%, it is wet dusty gas, the following points should be noted:
  • The vapor will make the dust wet and sticky, therefore, the filter cloth with a smoother surface and water resistance treatment should be selected.
  • High temperatures and high humidity simultaneously will lower the temperature resistance and service life of the filter fabric, especially for materials with poor hydrolytic stability such as Polyester.
  • For wet dusty gas, round filter bags should be used instead of flat filter bags and other complex-shaped dust filter bags.
• According to the corrosiveness (pH value) of dusty gas. Different material has different chemical resistance properties, and it is also affected by multiple factors such as temperature and humidity.
• According to the combustibility and explosiveness of dusty gas.

• The shape and particle size distribution of the dust. The nature aerosol particles and high-temperature combustion products are mostly regular-shaped dust, with smoother surfaces and smaller specific surface areas, which are not easily captured when passing through a filter media. Most of the produced dust particles are irregular, typical particles from the crushing and grinding production, they have a rougher surface and larger specific surface area, and they are easily captured and agglomerated when passing through the filter bags. 
• Adhesion and cohesion of dust. For dust with strong adhesion, filament woven fabric filter cloth, or needle felt with calendaring, coating, and membrane treatment should be selected. In terms of material.
• Hygroscopicity and deliquescence of dust. Some dust such as CaO, CaCl2, KCl, MgCl2, etc. who are easy to absorb moisture or even deliquesce then stick to the filter bag surface, filter materials with a smooth surface to easy dust removal should be selected also, and the surface of the cloth would be treated with oil and water repellent.
• The abrasiveness of dust. For aluminum powder, silicon powder, carbon powder, sintered ore powder and other abrasive particles, the following points should be noted.
  • a. Chemical fiber is better than glass fiber, and texturized glass fiber is better than the general.
  • b. Short, thin and frizzy fibers are better than thick, long and smooth fibers.
  • c. Non-woven needle felt is better than woven filter cloth.
  • d. Surface coating, calendering and other finished could also improve the wear resistance of the filter fabrics. For glass fiber filter cloth, silicone oil, graphite, PTFE treatment enhances its wear resistance and folding resistance.
• Flammability and explosiveness of dust, Flame-retardant and anti-static filter fabrics should be selected for flammable and explosive dust.

Different types of dust collector with different dust removal methods should match different types of filter materials, because of the differences in dust removal energy and filter bag characteristics.

• For the mechanical vibration baghouse dust collector, should choose thin, smooth filter fabrics with a soft texture, which could help to vibration waves transfer and remove dust easily.
• The sub-chamber air reverse bag filter dust collector should use thin, soft easily deformed filter fabrics but stable in dimensions.
• Vibration air reverse dust collector should use a thin needle felt with reinforced scrim in good dimensional stability.
• Rotary air reverse bag filter house should use soft, stable and good abrasion resistance filter cloth, preferably medium thickness needle felt filter fabrics.
• Pulse-jet bag filter dust collector should use thick needle felt filter fabrics with good wear-resistant and strong tensile strength.