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Photometer
Detector System
Pressure Transducer
Ozonator Lamp Power
Photometer Lamp Power
Photometer Temperature
Thermistor
Sample/Reference
Solenoid Valves
Thermo Fisher Scientific
During standby operation, a continuous flow of gas is necessary through the
oven. The standby flow and operating flow should be the same to +10
percent. This is achieved by setting the pressure regulator to the same
pressure setting as the back pressure regulator. In practice, rather than
measuring the pressure, it is the actual flows that are measured while
adjusting the pressure regulator. Two solenoids are used to change the flow
of gas going through the oven to the main stream or to vent.
The photometer has an airtight chamber that contains the sample and
reference gases and includes a photometer lamp at one end and a detector at
the other end.
The photo tube in the detector transmits light intensity information to the
measurement interface board for sample measurement computations.
The pressure transducer measures the pressure of the sample gas.
Ozonator
The internal ozonator operates on the photolytic principle and the ozone
level produced is a function of light intensity at 185 nm and gas flow. The
light intensity is varied by changing the current into the lamp. The gas flow
is held constant by a pressure regulator followed by a capillary.
The ozonator lamp power supply generates high voltage AC and contains
heater control circuits for the ozonator lamp.
Supply
The photometer lamp power supply generates high voltage AC and contains
heater control circuits for the photometer lamp.
Supply
The photometer temperature thermistor is used for controlling the
photometer at a consistent temperature.
Pump
The pump draws the sample gas through the photometer.
The sample/reference solenoid valves allow sample gas or reference (zero)
gas to pass through the cell.
System Description
Flow System
Model 146i Instruction Manual
8-5
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Troubleshooting
