Teledyne 2020 - Explosion proof thermal conductivity analyzer - Manual (Page 34)

Teledyne Analytical Instruments
3 Installation Model 2020
3-16
3.4.6 ZERO Gas
For the ZERO gas, a supply of the background gas, usually containing
none of the impurity, is required to zero the analyzer during calibration.
For suppressed zero ranges the zero gas must contain the low-end concen-
tration of the impurity.
NOTE: Because most cylinder gases are between 99.95 and 99.98%
pure, it is highly recommended that the same cylinder of gas
be used for both REFERENCE and ZERO gas.
NOTE: It is essential to the accuracy of the analyzer that the purity of
the zero gas be known. Otherwise, when the zero control is
adjusted during zero standardization, the reading will indicate
the impurity content of the zero gas, rather than zero.
3.4.7 SPAN Gas
For the SPAN gas, a supply of the background gas containing 70-
100 % of the component of interest is required as a minimum.
Note: If your analyzer range is set for inverting output, your zero
gas will be at 100% of the range interest, and span will be 70
to 100% of the low end range.
If linearization is required, intermediate concentrations of the target
gas in the background gas may be necessary. From one to nine separate
span gases may be used, depending on the desired precision of the linear-
ization. See chapter 4, Operation.
3.5 Testing the System
Before plugging the instrument into the power source:
• Check the integrity and accuracy of the gas connections. Make
sure there are no leaks.
• Check the integrity and accuracy of the electrical connections.
Make sure there are no exposed conductors
• Check that the pressure and flow of all gases are within the
recommended levels, and appropriate for your application.
Power up the system, and test it by performing the following
operations:
1. Repeat the Self-Diagnostic Test as described in chapter 4,
section 4.3.5.