The dust removal mechanism of bag filter is sieving, inertial collision, static electricity and diffusion, and gravity.
1. sieving
when the particle size of dust is larger than the pores of the filter cloth or the pores between dust particles deposited on the filter cloth, the dust is trapped. Because the pores of the new filter cloth are much larger than the particle size of dust, the retention effect is very small. When a large amount of dust is deposited on the surface of the filter cloth, the retention effect is significantly increased.
2. Inertia collision
When the dusty airflow approaches the filter cloth fiber, the airflow will bypass the fiber, and the dust particles will continue to move straight ahead due to inertia, and will be trapped when they hit the fiber. All the big dust particles within the critical line of dust trajectory can reach the surface of the fiber and be trapped. This inertial collision effect is enhanced with the increase of dust particle size and velocity.
3. Static electricity and diffusion
less than 1? When the air velocity is very low, the removal of m dust particles mainly depends on diffusion and electrostatic action. Less than 1? M's dust particles leave the streamline under the impact of gas molecules and do Brownian motion like gas molecules.
if it comes into contact with fibers during the movement, it can be separated from the airflow, which is called diffusion. If there is an external electric field, the electrostatic effect can be strengthened, thus improving the dust removal efficiency.
4. Gravity
When the slowly moving dusty airflow enters the dust collector, dust particles with large particle size and density may naturally settle down due to gravity.
Advantages of bag filter
1. The dust removal efficiency is generally above 99%, and the dust concentration in the outlet gas of the filter is within tens of mg/m3, which has high classification efficiency for fine dust with submicron particle size.
2. The range of treatment air volume is wide, rang1m1ming from a few m3 per minute to tens of thousands of m3 per minute, which can be used for flue gas dust removal in industrial furnaces and kilns to reduce the emission of atmospheric pollutants.
3. Simple structure and convenient maintenance and operation.
4. On the premise of ensuring the same high dust removal efficiency, the cost is lower than that of electrostatic precipitator.
5. When using high temperature resistant filter materials such as glass fiber, PTFE and P84, it can operate at high temperature above 2℃.
6, insensitive to the characteristics of dust, not affected by dust and resistance.
the above content reference: Baidu encyclopedia-bag filter