Teledyne 5000B - Near Infrared Photometer - Manual (Page 82)

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4 Operations/Analysis Unit
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
or 85 ppm simulated water using
span flag on top of dry liquid TDI
delta 80 ppm agreement on slope
sensitivity.
or
0 ppm water in N2 5 ppm water on the 5000B meter
or output with zero-flag/offset
intro.
0 ppm water in N2 delta 80 ppm simulated sensitivity
change of water.
Note: the span flag checks the sensitivity change of the 5000B
and not the zero drift of the analyzer. The mole sieve dried TDI
checks the zero of the instrument provided it can be reproduce the
zero by consistently removing all the water to the same ppm level,
(somewhere in the 2-10 ppm water range). The long term
efficiency of removing the water by mole-sieve contact should be
known for the customers process fluid, otherwise the customer
should have an acceptable off line lab technique to analyze
prepared samples be fore intro into the 5020 field analyzer. With
Teledyne’s approach, using N2 as the dry background for both
zero and span checks, eliminates the concern of the mole-sieve
being saturated with time. Indeed, the N2 Nitrogen background
approach can be used to verify the inefficiency of the mole-sieve
(saturation). Teledyne prefers this approach using easily
reproducible N2 since it is much simpler to flush out the sample
cell and check the instrument provided the original calibration on
TDI is used to set up the zero and span instruments of the optical
filters. See attached piping on how the appropriate valves are
operated to switch in N2 in the reverse mode to provide a stable
zero and or span check.