FUJITSU MPE3XXXAE - Manual (Page 48)

C141-E093-01EN 4 - 3
4.2.5 Air filter
There are two types of air filters: a breather filter and a circulation filter.
The breather filter makes an air in and out of the DE to prevent unnecessary pressure around
the spindle when the disk starts or stops rotating. When disk drives are transported under
conditions where the air pressure changes a lot, filtered air is circulated in the DE.
The circulation filter cleans out dust and dirt from inside the DE. The disk drive cycles air
continuously through the circulation filter through an enclosed loop air cycle system operated
by a blower on the rotating disk.