The filter system consists of two HEPA filters for downflow (supply) and
exhaust air.
Room air is drawn into the sample chamber through the work position
window opening. The room air is drawn into the negative pressure drain
pan air duct, then
pulled into the air
plenum in the top
portion of the cabinet.
The room air is mixed
with recirculating
HEPA filtered air from
the chamber, and
filtered proportionally
by the downflow and
exhaust filters. The
filtered air is then
supplied as ultra-pure
air into the sample
chamber of the unit,
and exhausted as
ultra-pure air into the
room environment, or
into an external
exhaust system via an
exhaust transition.
Sectional paper catch grids are installed beneath the work tray in the air
duct between the inner and outer back wall of the unit. These grids
prevent large items such as paper towels and tissues from entering the
plenum where they may impair the function of the blowers or the filters.
The grids can be easily removed for cleaning.
1-4 1500 Series A2
Thermo Scientific
Section 1
Description
HEPA Filters
Ultrapure air
Exhaustairfilter
Exhaustblower
Supplyblower
Supplyfilter
Ultrapureair
Downflow
inchamber
Blendedair
Papercatch
screens
Roomair
Figure 1-2.
Airflow Filtering System
Paper Catch Grids