Spectrex 20/20F - Fast UV/IR Flame Detector - Manual (Page 8)

Spectrex Inc. - SharpEye TM UV/IR (F) Flame Detector Manual – TM756100 Rev A, July 2005
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2. Technical Description
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Detection Range
: Up to 20 ft (6m) for a 1ft x 1ft (0.3m x 0.3m) Gasoline
fire.
•
Ultra High Immunity to False Alarm (see section. 3.3.).
•
Advanced Digital Processing of the Dynamic Characteristics of Fire:
Flickering and threshold
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Dual Spectrum
: UV and IR radiation
•
Solar Blind
•
Electrical Interface: Dry contact relays
•
UV/IR Dual Spectrum Design
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Fast Response Time:
Less than 5 milliseconds
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Built In Sensitivity Compensator
•
Filed of View: 90º Horizontal
70º Vertical
•
Explosion Proof: ATEX Approved
•
M.T.B.F Minimum 100,000 Hour
2.1 Principles Of Operation
The Model 20/20F Radiation Flame Detector is an electronic device designed to
sense the occurrence of fire and flames and subsequently activate an alarm or
an extinguishing system directly or through a control circuit.
The UV-IR Radiation Flame Detector is a dual spectrum optical detector sensitive
to two separate ranges of the radiation spectrum, both of which are present in
fires. The detector monitors the protected volume, by measuring the radiation
intensity in it, within two frequencies ranges of the electromagnetic spectrum,
namely the Ultra-Violet (UV) and the Infra-Red (IR).
2.2 Sensing Elements
The IR sensor is sensitive to radiation over the range of 2.5-3.0 micron. The IR
channel will register a detection signal, at the appropriate level, when the IR
sensor is exposed to radiation in the appropriate frequency range, having an
intermittent gleam pattern characteristic to flickering-fire, and a preset threshold
and time duration are reached.
The UV sensor is sensitive to radiation over the range of 0.185-0.260 micron.
The UV channel incorporates a special logic circuit that eliminates false alarms
caused by solar radiation and other non-fire UV sources. Further more; the UV
channel sensitivity is stabilized over the working temperature range.