Perma Pure Ambi-GASS - Manual (Page 5)

5 Ambi-GASS User Manual
2. Ambi-GASS Components
2.1 Filtration
The first step in conditioning the sample is to filter out particulate and aerosols. This
is accomplished by passing the sample through a 1
μ filter which has a borosilicate
glass filter element with a fluorocarbon binder. The element is disposable. In
addition to removing particulate, the filter coalesces liquid aerosols and droplets.
Two flow patterns are possible with this filter:
1. Installed with flow passing from the
outside to the inside of the element, the
element will act as a particulate filter only.
The advantage of this installation is that
collected particulate will build up on the
outside surface of the element, allowing
visual inspection of the element’s condition.
2. Installed with the flow passing from the
inside of the element to the outside, the
element will act as both a particulate and
a coalescing filter. Figure 2 details the
flow through the filter housing and element.
2.2 Automatic Filter Drain (optional)
If coalescing is anticipated, an automatic filter drain is needed in the system to periodically
remove collected liquid mists (usually acid mists). The automatic drain will operate in a
vacuum or pressurized system.
1. Vacuum Configuration
Collected liquid is withdrawn from the filter drain port by a strong vacuum created
by an eductor expanding compressed air through a venturi. This is done in
cycles, controlled by an adjustable digital timer that switches a solenoid valve
and controlling the compressed air supply.
2. Pressurized Applications
An eductor is not required since a vacuum is not needed to withdraw the
sample. Therefore, condensate withdraw is directly controlled by the solenoid
valve. Cycle times can be varied and will be dependent on the amount of
liquid present in the sample.
2.3 Nafion ® Dryer
The Perma Pure Nafion membrane dryer is installed downstream of the filter. As
sample enters the dryer, the flow splits into a number of small diameter Nafion
membrane tubes arranged in a parallel bundle (see Figure 3 on page 6). After the sample
enters one of these tubes it comes in contact with the Nafion membrane walls. The
membrane selectively removes water vapor from the sample by a process of
permeation distillation. Water vapor travels through the tubing walls driven by the
difference in partial water vapor pressure on the opposing sides of the membrane.
As the sample flows from inlet to outlet water is continually removed, reducing the
sample dew point as it travels through the dryer. Dry purge gas enters the dryer at
the sample outlet end and provides a medium for the water vapor from the sample to
be carried away.
Figure 2