Teledyne Analytical Instruments 3020 M, Operating Instructions Manual

Page: 39 / 107

Operational Theory Model 3020M-ATEX
Teledyne Analytical Instruments 16
With gas mixtures the components are weighted according to their
proportional volumes.
The cross interference with a gas mixture can be determined in
advance if the concentration of the individual background gases is
known.
Example:
Cross sensitivity calculation for a gas mixture:
The gas to be measured consists of 10% CO
2
, 40% N
2
, and 50% Ar.
CO
2
: -0.27 x 10% = -0027
Ar: -0.22 x 50% = -0.11
TOTAL CROSS INTERFERENCE = -0.137
Calculation of the zero value:
(0% O
2)
- (Cross Interference Value) = Zero Point Value
0% - (-0.137) = + 0.137% O
2)
2.4 Sample System
The Model 3020M sample system is designed and fabricated to
ensure that the oxygen concentration of the gas is not altered as it travels
through the sample system. The sample encounters almost no dead
space. This minimizes residual gas pockets that can interfere with trace
analysis.
The sample system for the standard instrument incorporates 6 mm
tube fittings for sample inlet and outlet connections at the bottom of the
housing or on the optional gas panel. Other size tube fittings are
available if needed.
Flame Arrestors and restrictors are placed on all gas inlets. The gas
restrictors are external to the flame arrestors.