Dust collector filter bag materials selection-Part 2
According to flammability and electric charge of dust particle:
Some dust will burn or blast when meet sparks in the air in a particular concentration state. The flammability of dust is related to its particle size, composition, concentration, combustion heat and combustion speed. The smaller the particle size is, the larger the specific surface area is, and the easier ignition is. An important condition of dust explosion is a confined space, in this space, the explosion concentration limit is generally tens to hundreds of grams / m3, dust combustion heat of combustion speed is high, the greater the power of the explosion. Dust combustion or explosion source is usually caused by friction sparks, electrostatic sparks, hot particles and so on, in which the charging is the most harmful. This is because the fiber filter is usually easy to charge, and if the dust with charge as well, it will be easy to make sparks, so for flammable and easy charged dust such as coal, coke powder, alumina powder and magnesium powder, should select a flame retardant filter fabric and conductive filter materials.
Solutions of dust collector baghouse filter bag material selection:
Generally it is believed that the materials whose oxygen index more than 30 is safe, such as PPS, P84 and PTEF filter materials and filter rolls.
And for filter materials whose oxygen index is less than 30 of the fiber, such as polypropylene, polyester, can be treated by flame retardant bathing.
Another anti static filter material is using static elimination method.
This anti static filter media means that the conductive fiber is mixed into the filter fiber, so that the filter material has conductive property in the direction or weft direction, so that the resistance is less than 109 ohms. The commonly used conductive fibers are stainless steel fiber and modified (carburizing) chemical fiber. Compared with each other, the conductivity of the former is stable and reliable, and the latter tends to decline after a certain period of time. The blending amount of conductive fiber is about 2% - 5% of the basic fiber.
For dust with flammability and electric charge, the best solution is using anti static baghouse filter bags made of Shanghai INDRO anti static filter materials.