Dust removal principle and influence factors of bag dust collector

Bag type dust remover is a device that suspends many filter bags in the dust chamber to purify dust-containing gas. Its main components are filter bags, shell, ash hopper and flying mechanism.

The dust removal mechanism of bag dust collector is complex, including inertial collision, interception, diffusion, gravity and electrostatic settling mechanism of dust particles. Generally speaking, the settling mechanism of dust particles on the trap is not only one settling mechanism, but the result of the joint action of many settling mechanisms.

 

(1) sieve effect. When the dust particle size is larger than the mesh of the filter bag or the intergranular pores deposited on the filter bag, the dust particles are retained on the filter bag or dust collecting layer. When the mesh of the new filter cloth fiber is larger than the particle size, the dust particles can pass through the mesh, and the screening effect is very small. However, after a large amount of dust particles deposited on the surface of the press cloth formed a dust layer, screening became the main dust removal mechanism.

(2) Inertial collision. When the dust air is near the press cloth fiber, the air will bypass the fiber. The larger dust particles, due to inertia, leave the flow line forward, impact on the fiber and capture, this is inertia collision. The inertial impact increases with the increase of particle size and velocity.

(3) Diffusion. Diffusion occurs in dust particles with small particle size. Under the impact of gas molecules, small dust particles break away from the streamline, make irregular Brownian motion like gas molecules, and get caught in contact with fibers. This effect is called diffusion effect. When the airflow velocity is reduced, the particle size decreases and the diffusion effect is enhanced.

(4) electrostatic effect. In general, both dust particles and filter bags may carry electrical charges, which follow the principle of like repel, opposite attract. The electrostatic effect is generally shown when the particle size is small and the flow rate is very low. The external electric field can strengthen the electrostatic effect, so as to improve the dust-proof efficiency.

(5) Gravity sedimentation. Dust particles with large particle size and density enter the dust collector, and when the flow rate is not large and the movement is slow, they can naturally settle down due to the action of gravity.

In general, a variety of dust removal mechanism will change with the gap of the filter bag, airflow speed, dust particle size and other factors, and the filtration performance of different filter bags is also different.


Post time: Mar-30-2021

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