GENERAL DESCRIPTION
8
A multiple-pane window assembly in the door of the chamber allows
viewing of the chamber interior during operation. The window is
constructed of tempered glass panes with a heater harness to assure frost-
free viewing during low temperature chamber operation. Under certain
ambient conditions, it may be normal to see some condensation around
the outer window frame area during low temperature operation.
REFRIGERATION/HEATING COMPONENTS
A. Refrigeration
ZP-Series chambers use one of three types of mechanical refrigeration
systems: single stage, Tundra®, and cascade. A single stage system is used
when the chamber’s ultimate low temperature is -30°F (-34°C) or higher.
The Tundra system is used when the chambers ultimate low temperature is
-50°F (-45°C) or higher. A cascade system is used when the chamber’s
ultimate low temperature is -94°F (-70°C). The single stage system uses
refrigerant R-404A. The cascade system uses refrigerant R-404A in System
#1 and R-508B/R-23 in System #2. The Tundra System uses refrigerant R-
410A.
The refrigeration system can either be air cooled or water cooled
depending on the model of chamber. Standard ZP-Series chambers above
3.5 HP are air cooled.
Chambers with compressors which are 10 HP (having nominally approx.
12kW of capacity with R-404A refrigerant at 60 Hz operation) and larger
are water cooled.
All refrigeration components are selected to ensure safe, reliable, and
balanced operation. The components may be purchased from the CSZ
Service Department or a local refrigeration wholesaler.
B. Heating
Open-coil nichrome heating elements are standard on all systems. The
heaters are mounted in porcelain insulators attached to stainless steel
frames. The heaters are located behind the rear plenum and do not
radiate directly into the test space.
Limited temperature sheath heaters are an option for chambers that may
contain flammable vapors. See the last section of this chapter for more
information.
To Next Page
Loading...
