Answer: Air flows in from the middle of the filter element and collects oil droplets through four mechanisms: gravity, inertial collision, direct interception and penetration.
(1) Gravity. When the air flow velocity in the filter is low, most of the oil droplets with a diameter of 20~50μm are collected by gravity free fall before reaching the filter layer, and the air flow continues to fall and collect when passing through the filter. The greater the air flow velocity, the lower the efficiency.
(2) Inertial collision. Suspended particles with a diameter greater than 1μm usually have a large impulse. They are not always consistent with the air flow path, so they will inertially collide with the fiber layer. The greater the air flow velocity, the greater the collision rate.
(3) Direct interception. Particles with a diameter of 0.3~1μm move with the air flow. Most of them will be intercepted and separated by the fiber layer at 1/2 of the filter element. The smaller the particle, the lower the interception rate.
(4) Penetration. Particles with a diameter less than 0.3μm. Because their mass is too small, they no longer have the usual properties of liquids. They move in an irregular Brownian motion that is inconsistent with the airflow path. This motion allows them to be captured by a finer filter layer. The smaller the particle, the more intense the Brownian motion, and the greater the chance of capture.
