Despatch RAD Series - Manual (Page 15)

RAD Oven Series Owner’s Manual T HEORY OF O PERATION
Version 1 15
Copyright © 2012 by Despatch Industries.
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Exhaust
damper
control
mechanism
3.
Theory of Operation
3.1. The RAD Oven Series
The RAD ovens (Figure 4) feature horizontal
recirculating airflow to ensure exceptional temperature
uniformity throughout the oven. A high-volume fan
circulates air through perforated, stainless steel walls to
create a constant horizontal airflow across all sections of
the oven. The result is proven reliability in demanding
production and laboratory applications, such as curing,
drying, sterilizing, aging, and other process-critical
applications.
3.2. Damper Control
Fresh air and exhaust dampers (Figure 5 and Figure 6)
control the amount of air exchanged as well as the oven chamber pressure. When the fresh air
damper is closed and the exhaust damper is open, oven chamber pressure tends toward negative.
When the fresh air damper is open and the exhaust damper is closed, the oven chamber pressure
tends toward positive (Table 1).
A negative oven pressure may draw ambient air into any
opening, causing cool spots to occur. The slightly
pressurized chamber produces the effect of pushing air to
the corners of the chamber. However, too much positive
pressure may force hot air or process vapors out of any
openings in the oven into the work area. Ideally, the fresh
air and exhaust dampers should be closed as much as
possible and the oven should be maintained at a neutral or
slightly positive pressure.
Figure 4. RAD Oven Series.
Figure 5. RAD Fresh Air Damper.
Figure 6. RAD Exhaust Damper.