1. What are the classifications of filters？

According to the performance of the filter (efficiency, resistance, dust holding capacity), it is usually divided into coarse efficiency, medium efficiency, medium efficiency, high efficiency (HEPA) and ultra-high efficiency (ULPA).

2. What is the filtration mechanism of the filter?

The filtering mechanism mainly includes interception (screening), inertial collision and so on.

① Interception: that is, sieving. Particles larger than the sieve holes are intercepted and filtered out, and those smaller than the sieve holes leak through. Generally, it has an effect on large particles, and the efficiency is very low. It is the filtration mechanism of the coarse filter.

② Inertial collision: Particles, especially larger particles, flow with the airflow and move randomly. Due to the inertia of the particles or the action of a certain field force, the particles deviate from the direction of the airflow and do not move with the airflow, but collide with and stick to obstacles and are filtered out. The larger the particle, the greater the inertia and the higher the efficiency. Generally, it is the filtration mechanism of coarse and medium efficiency filters.

3. What is the filter material and structure of the filter?

The filter material of the coarse filter is generally: glass fiber, chemical fiber, non-woven fabric, etc. Its structure types are mostly plate type, folding type and bag type. The filter material of the medium-efficiency filter is generally glass fiber, chemical fiber, non-woven fabric, etc. Its structure types are mostly bag type and wedge-shaped folded type. The filter material of the high-efficiency filter is mainly ultra-fine glass fiber filter paper. The structure is foldable. There are partitions and no partitions.