Spectrex 40/40UFL Ultra Fast UV/IR - Manual (Page 17)

TM 40/40UFL, Rev (2) August 2013
Principles of Operation 5
The detector integrates two dependent channels in which appropriate
detection pulses are registered and further analyzed for frequency, intensity
and duration.
 Sensing Elements
The IR sensor in Models 40/40UFL is sensitive to radiation over the
range of 2.5-3.0 micron where the H
2
emission has a unique spectral
peak that enables detection of hydrocarbon fires, gas fires, hydroxyl and
hydrogen fires as well as metal and inorganic fires.
The UV sensor is sensitive to radiation over the range of 0.185-0.260
µm. The UV Channel incorporates a special logic circuit that eliminates
false alarms caused by solar radiation and other non-fire UV source.
Furthermore, the UV channel’s sensitivity is stabilized over the working
temperature range.
 Detection Levels
Simultaneous detection of radiation in both the UV and the IR channels
having an intensity that exceeds the detector’s preset Warning level
results in a Warning signal.
Simultaneous detection of radiation in both the UV and the IR channels
having an intensity that exceeds the detector’s preset Alarm level results
in an Alarm signal.
Simultaneous detection of radiation in both the UV and the IR channels
having an intensity that exceeds the detector’s preset Flash-Fire
Detection level results in an immediate Alarm signal.
Since the preset dual range and level of radiation, as well as the flickering
pattern, are characteristics of real fire, all other radiation sources apart from
actual fire are not detected, thus avoiding false alarms.
1.4.2 Heated Optics
The SharpEye 40/40 Flame Detectors use heated optics. The heater
increases the temperature of the optical surface by 5-8°F (~3-5°C) above
the ambient temperature to improve performance in icing, condensation and
snow conditions.
The heated optics can be set to one of the following:
 Not operated
 On continuously
 Automatic, per temperature change (default): you can define the start
temperature below which the window is heated. (The default is 41°F
(5°C).) This temperature can be defined between 32°F (0°C) to 122°F
(50°C). The heating stops when the temperature is 27°F (15°C) above
the start temperature.
For more information, see Configuring your Detector on page 29.