Teledyne GFC-7001E - Trace CO Analyzer - Manual (Page 69)

Optional Hardware and Software Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 69
5.6.4. ZERO/SPAN VALVE WITH INTERNAL CO SCRUBBER (OPTION 50H)
Option 50H is operationally and pneumatically similar to Option 50A above, except that the zero air is generated
by an internal zero air scrubber. This means that the IZS inlet can simply be left open to ambient air.
Internal zero/span and sample/cal valves control the flow of gas through the instrument, but because the
generator and calibrator limit the flow of zero air and span gas no shutoff valves are required.
5.6.4.1. Internal Pneumatics (OPT 50H)
Figure 5-7: Internal Pneumatic Flow OPT 50H – Zero/Span Valves with Internal Zero Air Scrubber
Table 5-3: Zero/Span Valve Operating States for Option 50H
MODE VALVE CONDITION
SAMPLE
(Normal
State)
Sample/Cal Open to SAMPLE inlet
Zero/Span Open to ZERO AIR scrubber
ZERO CAL
Sample/Cal Open to ZERO/SPAN valve
Zero/Span Open to ZERO AIR scrubber
SPAN CAL
Sample/Cal Open to ZERO/SPAN valve
Zero/Span Open to PRESSURE SPAN inlet