Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 50)

Getting Started Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 32
3.6.3. Pneumatic Connections in Multipoint Calibration Applications
Some applications may require multipoint calibration checks where span gas of several different
concentrations is needed. We recommend using high-concentration, certified, calibration gas supplied to
the analyzer through a Gas Dilution Calibrator such as a Teledyne Instruments Model T700. This type of
calibrator precisely mixes Span Gas and Zero Air to produce any concentration level between 0 ppm and
the concentration of the calibrated gas.
Figure 3-12 depicts the pneumatic set up in this sort of application of a Model GFC 7000TA CO
2
Analyzer
with ambient zero/ambient span valve option 50A installed (a common configuration for this type of
application).
Figure 3-15: Example of Pneumatic Set up for Multipoint Calibration
3.6.4. Setting the Internal Purge Air Pressure
In order to maintain proper purge air flow though the GFC wheel housing, a manually adjustable pressure
regulator is provided (see Figure 3-5). This regulator includes two output ports. One is used to supply
purge air to the GFC wheel. The other may be used to attach a pressure gauge.
To adjust the internal purge air pressure of the GFC 7000TA:
1. Turn off the instrument.
2. Remove the source of zero air attached to the purge line inlet port at the back of the analyzer.
3. Remove the analyzer’s top cover.
4. Remove the cap from the second, unused, output port on the pressure regulator.
5. Attach a pressure gauge capable of measuring in the 5-10 psig range with 0.5 psig resolution to
the port.