ThermoFisher Scientific HERASAFE 2025, Operating Instructions Manual

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50161258 HERAsafe 2025
Chapter 4
Filter System
Herasafe 2025
Figure 4 Filter System with Downflow Filter and Exhaust Air Filter
The filter system consists of two HEPA filters [2] and [5] for the circulating air and for the
exhaust air and a coarse filter for the aspired air.
HEPA filters: Room air [10] is drawn into the sample chamber through the working opening.
In the air duct, room air and the downflow within the chamber [7] are then blended to make
up the blend air [9]. The blend air is then:

filtered proportionally by the downflow filter [5] and supplied as ultrapure air [6]
evenly into the sample chamber of the device,

filtered by the exhaust air filter [2] and released as ultrapure air [1] to the exterior of the
device.
Inlet air protection: The air duct between the sample chamber and the device plenum
has an inlet air protection [8] below the working surface to prevent coarse particles from
entering the plenum where they may impair blower [3] and [4] and filter functions.