There are four main mechanisms by which air filters work: straining, impingement, diffusion, and interception. Straining occurs when larger particles are too large to pass between the filter fibers. Impingement happens when inertia causes larger, denser particles to collide with fibers. Diffusion captures the smallest particles through Brownian motion collisions with fibers. Interception uses an electrostatic charge to pull particles towards fibers. Together, all of these mechanisms operating simultaneously determine the overall efficiency of the air filter over time.
21. Now, the great thing about these
filter mechanisms is that they do not
operate alone.
22. A filter could be employing thousands
of instances of these filtration
mechanisms at any one time.
23. The efficiency of each mechanism will
fluctuate over the life of the filter...
Efficiency
Time
ELECTROSTATIC
STRAINING,
IMPINGEMENT
& DIFFUSION
ELECTROSTATIC
STRAINING,
IMPINGEMENT
& DIFFUSION