Teledyne 3000TA-XL-EU, Руководство по эксплуатации

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Operation 3000TA-XL-EU
Teledyne Analytical Instruments 54
A trace cell is unlikely to fail span. As explained before, when the
sensor reaches the end of its useful life, the zero offset begins to rise
until the analyzer finds the zero unsatisfactory. Nevertheless, feeding
the wrong span gas or electronics failure could set this feature off at the
end of the span. Consider this before replacing the cell.
4.5 Switching of Sample Streams
The Model 3000TA-XL-EU may be used to monitor more than one
type of sample gas, such as nitrogen and helium, or two streams of
nitrogen containing low (less than 1 ppm) and high (5000 to 10,000
ppm) concentrations of oxygen.
For these applications, we recommend the following parameters
and conditions be followed:
1. While switching streams, such as between nitrogen and
helium, both the gas streams must be made to flow
continuously even through only one stream is going through
the analyzer at one time. Failure to do so may result in
spikes in output when the dead-ended stream is switched in.
For further information, read the Technical Bulletin -
TB00001, dated 3-98. This Bulletin is available upon request
from TAI.
2. The analyzer is capable of handling the switching of streams
without affecting the sensitivity of the cell. This switching of
streams between nitrogen and helium will not require SPAN
adjustment. However, care must be taken to keep sample
flow rates in the desired levels, as the flowmeter is calibrated
for air and nitrogen streams only.
3. The analyzer can withstand repeated switching of streams
between low oxygen levels of less than 1 ppm and high
oxygen levels of 5000 to 10,000 ppm. Again, care must be
taken to ensure proper and continuous flows at all times.
4.5.1 Special Notes on Hydrogen Gas Stream
The standard oxygen cells, Model B-2CXL and Insta-Trace, though
tested in nitrogen gas streams, are expected to perform well in hydrogen
streams. However, for certain applications such as continuous
monitoring of very low levels of oxygen in hydrogen, the user may