The adsorption type (activated carbon) filter that uses the surface to generate attractive force has a limited service life, and the adsorption capacity of the adsorbent decreases after the oil is absorbed.
The main material absorbents of absorption filters, such as wool, linoleum and cotton, will lose their structural advantages and quickly fail after they absorb liquid into the interior and infiltrate them.
Mechanical separators and screen air filters, usually classified as 5, 10, 20, and 40μm, are ineffective for the tiny particles that account for most of the oil droplets.