Figure 8-1. Hardware Components - Thermo Scientific 42i Instruction Manual

System Description
NO2-to-NO Converter
Pressure Transducer
Input Board
HVPS
Thermistor
Measurement
Interface Board
Power Supply
NO -to-NO Converter
2
Mode Solenoid
Reaction Chamber
8-2 Model 42i Instruction Manual
Flow
Converter
Transducer
Scrubber
Ozonator Ozonator
Transformer
Figure 8–1. Hardware Components
The NO -to-NO converter heats molybdenum to approximately 325 °C in
2
order to convert and detect NO
housing, heater, replaceable cartridge, and a type K thermocouple sensor.
The mode solenoid valve switches analyzer operation between the NO
mode and NO mode. It routes the ambient air sample either through the
x
reaction chamber (NO mode) or through the NO
then to the reaction chamber (NO
The reaction chamber is where the sample reacts with ozone and produces
excited NO that gives off a photon of energy when it decays.
2
The reaction chamber is heated and controlled to approximately 50 °C in
order to ensure the greatest instrument stability. The sample and ozone
flow capillaries and a thermistor sensor are also housed in/on the reaction
chamber assembly.
Reaction
PMT Assembly
Chamber
Flow
Switch
Motherboard Digital Output Board
Solenoid
. The converter consists of an insulated
2
mode).
x
Capillaries (2)
Pump
I/O Expansion
Board (Opt)
-to-NO converter and
2
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