VICI 235 Dynacalibrator - Manual (Page 12)

8
Span Outlet
The primary outlet on the Model 235 is labeled SPAN OUT. The SPAN OUT port
may be either permanently plumbed to the calibrate input port of an analyzer
or temporarily connected to its sample input for calibration, depending on the
capabilities of the analyzer.
NOTE: The Span Out port should be directly connected to the
analyzer input with a minimum length of tubing. Altering
the output stream in any manner may affect the concentra-
tion of calibration gas in the stream. Use tubing which will
provide the low back pressure for the required delivery flow
for the analyzer.
Overflow Vent
All Dynacalibrators include an overflow vent to dump excess calibration gas,
ensuring that analyzers sensitive to sample feed pressure receive span gas at
near atmospheric pressure. The overflow vent is therefore usually left open,
or plumbed to an external exhaust point with large diameter tubing. External
devices (filters, etc.) or tubing with too small a diameter on the overflow vent may
cause an undesirable increase of pressure at the analyzer’s input.
Front Panel Features
MAIN POWER switch
The rocker switch on the upper left corner of the front panel provides primary
power to all circuits.
PERMEATION CHAMBER
This is the high accuracy oven which holds the permeation devices. A tool is
provided to rotate the panel lock screw 90° counterclockwise to unlock the cap.
If the oven door is not in place and in the locked position, the oven will not be
powered and will not heat. The actual chamber temperature is recorded into
the database on one minute intervals, for a maximum period of one week.
Figure 4: Model 235 front panel
Getting Started
SHUTDOWN
30° 120°
POWER
Metronics
PERMEATION CHAMBER LOCK