Shel lab SVAC9-2, Installation And Operation Manual, Page: 28 / 46

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OPERATION
T
HEORY OF
O
PERATION
The SVAC9-2 is intended for use in closed cycle under vacuum applications such as drying, baking
out volatiles, and evolutions of molecular clouds.
Vacuum
Vacuum is supplied to the oven chamber by a vacuum pump or building system. The vacuum supply
is connected to one of the two (2) KF-25 fittings on the oven. The oven chamber is pressure rated to
10 millitorrs at near sea level. Vacuum levels obtained in the oven chamber are dependent on pump
performance, valve settings, and the nature of the application or process, including the volume of
material outgassed.
The chamber must be sealed and evacuated at the start of a vacuum baking application. The oven is
not built to operate with the chamber exposed to free atmosphere. Running the oven with the door
or the vent open may risk destroying the vacuum pump and damaging the integrity of the oven
chamber.
Vacuum pumps and door gaskets should be selected based on the application or process. Gasket
types are resistant and vulnerable to different chemicals, and vacuum pumps vary in suitability and
safety depending on the outgassed byproduct types and moisture level produced in the oven
chamber.
The vacuum gauge on the control panel displays the chamber atmospheric pressure in Torr and
mTorr (millitorr).
Backfilling
A gas supply can be connected to the vent intake port (backfill inlet). Nitrogen or another inert gas
may be used to backfill an evacuated oven chamber to avoid particulate contamination or oxidation.
The maximum allowed backfill pressure is 15 psi of delivery at the inlet port.
Heating Options
The oven can either heat to and run at a constant temperature set point or execute automated
multistep heating profile recipes with ramp up, heat soak, and ramp down steps. Heating recipes are
programmed as profiles by the end-user.