Teledyne T360M Carbon Monoxide Alarm User Manual


 
Principles of Operation Teledyne API Model T360/T360M Operation Manual
200
7.3. PNEUMATIC OPERATION
CAUTION
It is important that the sample airflow system is both leak tight and not
pressurized over ambient pressure. Perform regular leak checks (refer to
the maintenance schedule, Table 6-1) on the analyzer as described in the
procedures for correctly performing leak checks in Section 6.3.3.
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.
By placing the pump down stream from the sample chamber several
problems are avoided.
First the pumping process heats and compresses the sample air
complicating the measurement process.
Additionally, certain physical parts of the pump itself are made of materials
that might chemically react with the sample gas.
Finally, in certain applications where the concentration of the target gas
might be high enough to be hazardous, maintaining a negative gas pressure
relative to ambient means that should a minor leak occur, no sample gas will
be pumped into the atmosphere surrounding analyzer.
7.3.1. Sample Gas Flow
Figure 7-8: Internal Pneumatic Flow – Basic Configuration
07272B DCN6552