Cascade Sciences CVO-10, Руководство по установке и эксплуатации

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OPERATION
T
HEORY OF
O
PERATION
Vacuum
Vacuum is supplied by an external vacuum supply (a pump or building system) connected to one of
the oven vacuum ports. Vacuum levels obtained in the oven chamber are dependent on pump type
and performance, valve settings, and the nature of the application or process, including the volume
of materials outgassed.
The chamber atmospheric pressure is displayed on the Vacuum Gauge on the control panel.
The chamber should be sealed and evacuated at the start of a vacuum baking application. The oven
is not built to operate with the chamber exposed to atmosphere. Running the oven with the door or
the vent open risks destroying the vacuum pump, damaging the integrity of the oven chamber, and
may oxidize chamber surfaces.
Vacuum pumps and door gaskets should be selected on the basis of application type or process.
Pumps vary in suitability and safety depending on the outgassed byproduct types and moisture level
produced in the oven chamber. Gasket types are both resistant to and vulnerable to different
chemicals.
Gas Backfill
A gas or clean air supply can be connected to the vent port (backfill inlet) or KF-25 port located on
the back of the oven. Nitrogen or another inert gas are typically used to avoid particulate
contamination or the oxidation of product that has not cooled down. The maximum allowed backfill
pressure is 15 psi of delivery at the port.
Heating in a Vacuum
In conventional ovens, powered elements transfer heat into the chamber air. The heated air then
circulates by natural convection or blower fan action, and surrounds the product on the shelves,
gradually bringing it to temperature. In a vacuum oven, heat transport takes place by both direct
infrared radiation from heated surfaces and from conduction. The oven heating elements are located
inside the chamber walls or floor, which transfer some heat to the shelves. Each shelf then transports
heat to the products or samples resting on it.