Photometer Layout And Operation; Figure 6-15. Typical Jumper Set (Jp2) Set Up Of Optional Metal Wool Scrubber Heater - Teledyne T400 User Manual

Figure 6-15. Typical Jumper Set (JP2) Set Up of Optional Metal Wool Scrubber Heater

6.3.6 P
HOTOMETER
The Photometer is the component where the absorption of UV light by ozone is measured
and converted into a voltage. It consists of several sub-assemblies:
• A mercury-vapor UV lamp. This lamp is coated in a material that optically screens the UV
radiation output to remove the O
emitted.
An AC power supply to supply the current for starting and maintaining the plasma arc of
•
the mercury vapor lamp.
• A thermistor and DC heater attached to the UV lamp to maintain the lamp at an optimum
operating temperature.
• 42 cm long quartz absorption tube.
• A thermistor attached to the quartz tube for measuring sample gas temperature.
Gas inlet and outlet mounting blocks that route sample gas into and out of the photometer.
•
The vacuum diode, UV detector that converts UV light to a DC current.
•
• A preamplifier assembly, which convert the Detector's current output into a DC Voltage
then amplifies it to a level readable by the A-to-D converter circuitry of the instrument's
motherboard.
083730400A DCN8130
L O
AYOUT AND PERATION
3
CAUTION – UV RADIATION RISK
Do not look at the UV lamp while the unit is operating. UV light can
cause eye damage. Always use safety glasses made from UV
blocking material when working with the UV Lamp Assembly.
(Generic plastic glasses are not adequate).
Teledyne API – Model T400 O
producing 185nm radiation. Only light at 254nm is
Analyzer
3
159