>Gauze filters rely on dirt buildup to increase filtration efficiency.
Yes, this is correct. As you build up material on the outside of the air
filter, the efficiency (retention of particles) will go up at the cost of
pressure drop. I think a year cleaning or cleaning after you have driven in
an dusty environment is the way to go in the absence of a differential
pressure measurement across the filter (manifold pressure guage).
There are 3 particle retention mechanisms in gas filtration:
- size exclusion
-impaction
-electrostatic
The small particles float around with brownian motion and don't find there
way through the pores of the filter. The big particles are caputred by size
exclusion or impaction on to the filter surface. But there is a "most
penetrating particle" - one with a certain size and velocity
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