Teledyne 212R - Thermal conductivity analyzer - Manual (Page 25)

Teledyne Analytical Instruments 25
Thermal Conductivity Analyzer Model 212R
7.2 Output Signal:
Output coincides with 100% analysis.
4mA = 0 ppm N
2
in H
2
20mA = 50,000 ppm N
2
in H
2
- Range #1
= 5000 ppm N
2
in H
2
- Range #2
= 500 ppm N
2
in H
2
- Range #3
7.3 Span Setting: 555
7.4 Recommended Accessory Gases.
H
2
Purity Zero Gas 99.999
H
2
Purity Reference Gas 99.999
Span Gas 350-450 ppm N
2
in H
2
7.4.1 Reference Gas.
With a equivalent impurity of less than 3% of range 1. The impurity ratio
must remain constant. When the reference gas supply is replaced, the analyzer
must be re-standardized.
7.4.2 Zero Gas.
Because of the difficulties involved in obtaining a gas in pure form, the zero
gas must be purchased from a supplier who will certify the cylinder as to its
content. The equivalent impurity concentration of the gas must be less than 3%
of range 1. When the zero gas is introduced for standardization, the range
switch must be
in Range 1, and the zero control set such that the recorder
indicates the zero gas impurity.
IMPORTANT: At startup, be sure that the span control dial is set to the
number recorded in Section 7.3.