Adsorbent Breather Filter0 pages

"

gl Donaldson.

nnnn

!SM FILTRATION SOLUTIONS

nnnn

ADSORBENT BREATHER

nnnn

FILTER (ABF)

nnnn

Disk Drive

nnnn

DESCRIPTION

nnnn

The Adsorbent Breather Filter (ABF) is

nnnn

comprised of a filtration membrane,

nnnn

adsorbent element, and a pressure-sensitive

nnnn

adhesive ring for securing the filter to the

nnnn

inside of the drive.

nnnn

A diffusion channel can be incorporated

nnnn

within the adhesive layers.

nnnn

PRINCIPLE OF OPERATION

nnnn

The ABF is designed to provide protection

nnnn

from particles, hydrocarbons, and acid gases.

nnnn

The high efficiency filtration membrane

nnnn

removes particles from incoming air and

nnnn

encapsulates the adsorbent element. The

nnnn

adsorbent is specially formulated to control

nnnn

humidity and to adsorb acid gases and

nnnn

hydrocarbons from internal and external

nnnn

sources. The most common adsorbents and

nnnn

their associated functions are as follows:

nnnn

• Activated Carbon: Relative humidity

nnnn

control and adsorption of hydrocarbons

nnnn

• Chemically Treated Activated Carbon:

nnnn

Relative humidity control and adsorption

nnnn

of acid gases and hydrocarbons

nnnn

• Silica Gel: Relative humidity control

nnnn

INSTALLATION IN DRIVE

nnnn

The ABF is located on the inside of the drive, preferably with

nnnn

a diffusion channel between the breather and the outside

nnnn

environment. The filter location should be in low pressure area

nnnn

of the disk drive so that air can enter through the breather.

nnnn

Generally, the best location is on the cover as close as possible

nnnn

to the spindle.

nnnn

Airflow restriction into the drive is affected by the size of the

nnnn

filter, choice of filter materials, and the design of the diffusion

nnnn

channel. There is a trade-off between the airflow restriction and

nnnn

the amount of diffusion protection.

nnnn

Adhesive

nnnn

Adsorbent Material

nnnn

Air Flow

nnnn

Adhesive

nnnn

PTFE Membrane

"