Teledyne T300, Руководство по эксплуатации, Страница: 305 / 426

Teledyne API – Model T300/T300M CO Analyzer Theory of Operation
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13.2.1.3. SUMMARY INTERFERENCE REJECTION
The basic design of the T300/T300M rejects most of this interference at a 300:1 ratio.
The two primary methods used to accomplish this are:
• The 4.7μm band pass filter just before the IR sensor which allows the instrument to
only react to IR absorption in the wavelength affected by CO.
•
Comparison of the measure and reference signals and extraction of the ratio
between them.
•
Pneumatic Operation
CAUTION – G
ENERAL
S
AFETY
H
AZARD
It is important that the sample airflow system is both leak tight and not pressurized
over ambient pressure.
Regular leak checks should be performed on the analyzer as described in the
maintenance schedule, Table 11-1.
Procedures for correctly performing leak checks can be found in Section 11.3.3.
An internal pump evacuates the sample chamber creating a small vacuum that draws
sample gas into the analyzer. Normally the analyzer is operated with its inlet near
ambient pressure either because the sample is directly drawn at the inlet or a small vent
is installed at the inlet. There are several advantages to this “pull through”
configuration.
06864B DCN6314