广州旺涛过滤器材科技有限公司
TECHNICAL TOPICS
 
An air filter refers to an air filtering device, is generally used for a clean workshop, a clean factory building, a laboratory and a clean room or dust prevention of electromechanical communication equipment and so on, and is divided into a low-efficiency filter, a medium-efficiency filter, a high-efficiency filter, a sub-high-efficiency filter and so on. Various types have different standards and use efficiency.  The air filter can be divided into a low-efficiency filter, a medium-efficiency filter, a high-efficiency filter, a sub-high-efficiency filter and so on according to the working principle.  Working principle:  Interception  Dust particles in air do inertial motion with air flow or do random Brownian motion or move under the action of field force, and are adhered to the fiber surface due to Van der Waals force (force between molecules and between molecular groups) existing between the objects when moving and running into other objects. Dust entering the filter medium has many opportunities to impact the medium, and can be adhered when run into the medium. Small dust collides and is bonded to form large particles for settlement, and the particle concentration of the dust in the air is relatively stable, that is why an indoor wall fades.  Inertia and diffusion  The dust particles do inertial motion in the air flow, the direction of the air flow is changed when the dust particles meet messily arranged fibers, and the particles deviate due to inertia, run into the fibers and are bonded. Larger particles more easily impact the fibers and achieve a better effect.  The small dust particles do random Brownian motion. The smaller particles do more violent random motion, have more opportunities to impact an obstacle and achieve a better filter effect. The particles with the size of less than 0.1 micron in the air mainly do Brownian motion. The smaller particles achieve a better filter effect. The particles with the size of more than 0.3 micron mainly do inertial motion. The larger particles achieve higher efficiency. The particles with unobvious inertia and diffusion are the most difficultly filtered out. When the performance of the high-efficiency filter is measured, people often stipulate a dust efficiency value which is the most difficultly measured.  Electrostatic action  For some reason, the fibers and the particles are possibly charged to generate an electrostatic effect. The filter effect of a filter material with static electricity can be obviously improved. Reason: the motion trajectory of the dust is changed, and the dust runs into the obstacle and is more firmly adhered to the medium due to the static electricity.  The material with the static electricity for a long time is also called an electret material, and has unchanged resistance, and the filter effect can be obviously improved. The static electricity does not play a decisive role in the filter effect and only plays a helping role.