Perma Pure ZERO-AIR GENERATOR - Manual (Page 4)

3 Form #240
Zero-Air Generator Manual Rev 11/98
Description of Components
2.1 Perma Pure Dryer
Water vapor and certain polar organic compounds (i.e. alcohols, ketones) are removed
here. A bundle of Nafion

tubes is housed inside the dryer shell. As the wet compressed
air flows through the tubes, the water vapor is absorbed through the membrane and
carried off by a counter-current purge air flow at a reduced pressure. The driving force for
this process, known as permeation distillation, is the difference in partial vapor pressure of
water between the product and purge gas flows. In this system, a portion of the dried air
is expanded and used as the purge gas.
Figure 2 – Perma Pure Nafion Membrane Dryer Schematic
2.2 Ultraviolet Lamp
Used for the destruction of bacteria into carbonaceous by-products. The lamp produces
approximately 1-3 PPM of ozone (O
3
), which then breaks down microorganisms into
carbon compounds that are removed further downstream. The lamp also oxidizes NO to
NO
2
, which is readily removed by system adsorbents.
2.3 Activated Carbon/Alumina Mixture
This is a blend of high performance activated carbon and impregnated alumina pellets.
This mixture will remove trace quantities of chlorine (Cl
2
), hydrogen fluoride (HF),
hydrogen sulfide (H
2
S), nitrogen oxides (NO
x
), ozone (O
3
), sulfur dioxide (SO
2
), sulfur
trioxide (SO
3
), and general hydrocarbons (HC). In addition to removing these substances,
the mixture changes from purple to brown, indicating the need for replacement.
2.4 Carbon Monoxide Catalyst
Palladium impregnated alumina pellets are used to convert low levels of CO to CO
2
. This
catalyst is not consumable, and should last for the lifetime of the unit.
2.5 1
µµµµ
Particulate Filter
The last stage of purification is the particulate filter. This filter has an absolute retention
rating of 1 micron, and a 93% rating for particles down to 0.1 micron. The disposable
filter is housed in a transparent plastic housing, allowing easy visual determination of the
filter’s condition.
2