Operation Summary; Sensor Module, Reaction Cell, Detector; Pneumatic Sensor Board - Teledyne 9110AH Instruction Manual

TELEDYNE Model 9110AH NO

4.2 Operation Summary

4.2.1 Sensor Module, Reaction Cell, Detector

The sensor module is where light from the chemilumenescent reaction is generated and
detected. It is the most complicated and critical sub-assembly in the entire analyzer. It consists
of the following assemblies and functions:
1. The reaction cell and ozone flow control module
2. Reaction cell heater/thermistor
3. PMT and High Voltage Power Supply
4. PMT cooler/cold block/heatsink/fan
5. Preamp assembly:
A. Preamp range control hardware
B. HVPS control
C. PMT cooler temp control
D. Electric test electronics
E. Optic test electronics

4.2.2 Pneumatic Sensor Board

The sensor board consists of 2 pressure sensors and a flow sensor. One pressure sensor
measures the pressure in the reaction cell. The reaction cell is maintained at about one-quarter
of atmospheric pressure. The second pressure sensor measures the pressure upstream of the
reaction cell, which is near ambient pressure. From these two pressures the sample flow rate
can be computed and is displayed as sample flow in the TEST menu. Finally, a solid state flow
meter measures the ozone flow directly. Likewise, it is displayed as a TEST function.
The M9110AH displays all pressures in inches of mercury-absolute (in-Hg-A). Absolute
pressure is the reading referenced to a vacuum or zero absolute pressure. This method was
chosen so that ambiguities of pressure relative to ambient pressure can be avoided.
For example, if the vacuum reading is 25" Hg relative to room pressure at sea level the absolute
pressure would be 5" Hg. If the same absolute pressure was observed at 5000 ft altitude where
the atmospheric pressure was 5" lower, the relative pressure would drop to 20" Hg, however
the absolute pressure would remain the same 5" Hg-A.
Analyzer Operator Manual, 01620, Rev. F
X
4-4