What is the working principle of high-temperature-resistant HEPA air filters?

The working principle of high-temperature resistant and high-efficiency air filters mainly includes interception, inertial collision, diffusion, electrostatic adsorption, and other functions, as follows:
Interception effect: The filter material of the filter has a certain pore structure. When dust particles in the airflow through the filter material with the air, particles larger than the pores of the filter material will be directly intercepted, just like a sieve sifting things. This is the most basic filtration mechanism.
Inertial collision: When the particles in the airflow have a relatively large inertia, due to the constantly changing direction of the airflow as it flows between the filter material fibers, the particles will deviate from the airflow direction due to inertia and directly collide with the fibers and be captured. This effect is more obvious for particles with larger diameters (greater than 1μm). For instance, in some industrial high-temperature environments, larger dust particles are more likely to be filtered out in this way.
Diffusion: For extremely tiny particles (less than 0.1μm), they will undergo random Brownian motion in the air. During the movement process, the probability of these particles coming into contact with the filter material fibers increases, and thus they are adsorbed on the surface of the fibers. In a high-temperature environment, molecular movement intensifies and diffusion becomes more pronounced, which helps to enhance the filtration efficiency for tiny particles.
Electrostatic adsorption: The filter materials of some high-temperature resistant and high-efficiency air filters are specially treated to carry a certain amount of electrostatic charge. When dust particles in the air pass through the filter material, they will be attracted by static electricity and adsorbed on the filter material. This electrostatic adsorption effect can significantly enhance the filter's ability to capture tiny particles and even sub-micron particles can be effectively filtered.
In practical work, high-temperature resistant and high-efficiency air filters usually achieve efficient filtration of dust particles in the air by comprehensively utilizing the above multiple principles. Different filters may focus on different working principles based on their designs and application scenarios to achieve the best filtering effect.