*TM 5-810-4/AFM 88-8, Chap. 3
under heavy dust conditions.
c. Dry filters have an efficiency of 99 percent of particles
larger than 10 microns. Because of their high filtration effi-
ciency, these filters are the best selection for rotary and
reciprocating compressors. They must be used for nonlubri-
cated compressors and whenever air must be kept oil-free.
d. Two-stage dry filters, to provide 99 percent efficiency
of particles larger than 0.3 micron. will be used for cen-
e. With all types of filters, a means of monitoring the air
pressure drop through the element must be provided. which
2-6. Dust and vapors.
All air compressors are sensitive to dust and airborne vapors
which can form adhesive, abrasive, and corrosive mixtures
ing parts and can induce excessive wear and mechanical
unbalance, thereby damaging the compressor.