A compressed air filtering cartridge includes a housing and a filter in
the housing, the filter having a thermal vent. In one embodiment the
filter includes a wall portion having a first condition when below a
predetermined temperature range in which the wall portion blocks flow of
air between opposite sides of the wall portion. The wall portion has a
second condition when above the predetermined temperature range in which
the wall portion does not block flow of air between opposite sides of the
wall portion. The cartridge may be part of a compressed air system,
between a compressor and an air dryer.