What are the functions of dust filtration
According to the different mechanical characteristics of the movement of dust with different particle sizes in the fluid, the filtration and dust removal mechanism involves the following aspects:
1. Screening function
The mesh of filter material is generally 5 ~ 50 microns. When the particle size of dust is larger than the mesh or pore diameter or the interstitude of dust deposited between the filter materials, the dust will be blocked. As for the new fabric filter, the gap between the fibers, namely the pore diameter, is much larger than the dust particle size, so the screening effect is very small. However, when a large amount of dust is deposited on the surface of the filter material to form a dust layer, the screening effect is significantly enhanced.
2. Inertial collision
Generally, dust with larger particle size is mainly collected by inertial collision. As the dust stream nears the fiber, it bypasses the fiber, and the larger particles (more than a muon), due to inertia, veer off the stream and continue in the same direction, hitting the fiber and trapping it. All dust particles in the critical boundary of dust track can reach the surface of the fiber and be arrested. The effect of inertia collision increases with the increase of dust particle size and airflow velocity. Therefore, the inertia collision can be improved by increasing the airflow velocity through the filter.
When the dusty air flow is close to the filter fiber, the fine dust particles will flow along with the air flow. If the dust particle radius is larger than the distance from the center of the dust particles to the fiber edge, the dust particles will be intercepted because of contact with the fiber.
Dust particles smaller than 1 muon, especially those smaller than 0. Two microns of submicron particles are separated from the stream by the impact of gas molecules, which act like gas molecules in Brownian motion and can be separated from the stream if they come into contact with the fibers. This effect, known as diffusion, is enhanced as the flow rate decreases and the diameter of fibers and dust decreases.
5. Electrostatic effect
Many fiber woven filter material, when the airflow through the produce electrostatic phenomenon, because of friction and dust in the process of delivery will be charged due to friction and other reasons, it will in the filter material and form a potential difference between dust particles, when the dust with air filter material trend, because the coulomb force to dust and collisions and increase of filter material fibre was arrested for dust adsorption force, improve the efficiency of capture.