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SharpEye
TM
IR3 Flame Detector User Guide
16
Principles of Operation
2.2.2
Identifying the CO
2
Peak
The hydrocarbon fire is characterized by a typical radiation emission. The
CO
2
peak emits intense radiation in the spectral band between 4.2–4.5µ and
weaker radiation intensity outside this spectral band.
2.2.3
Limitations of IR-IR Flame Detectors
CO
2
in the atmosphere attenuates the radiation in this spectral band.
(Absorption and emission of radiation always occur in the same band.) As a
result, the greater the distance between the detector and the fire, the
weaker the intensity of the radiation reaching the detector is (i.e. the CO
2
attenuation increases). This phenomenon explains the limitations of the
existing IR-IR flame detectors in the market:
Detection distance is restricted to 33ft/10m only.
Their immunity to false alarm sources is limited.
2.2.4
Advantages of IR3 Technology
To overcome these limitations, SPECTREX devised an innovative concept of
utilizing an additional detection channel. Three channels collect more data
from the environment, giving analysis which is more accurate and better
performance.
After careful investigation, 3 channels were selected which, when operating
jointly, provide optimal fire detection characteristics:
Channel 1
: 4.2–4.6µ
Fire - the CO
2
peak
Channel 2
: 4.0–4.2µ
Eliminates false alarms from high temperature sources
Channel 3
: 4.8–5.2µ
Eliminates false alarms from flickering of background radiation
Most IR sources which create misleading IR alarm stimuli, including the sun,
incandescent and halogen lamps, electric arc discharges, electrical heaters,
etc., do not possess this unique spectral signature of fire.
The IR sensors of the detector respond only to flickering of radiation signals.
The signals are compared to a predetermined threshold. Processing of the
results from the 3 IR channels is performed by the board microprocessor.
The result is a much greater detection distance and a highly increased
ability to distinguish between fire and false alarms.
This sophisticated technology surpasses all other existing flame detection
techniques on the market today.
Note
: This unique flame analysis capability (patent pending) has been
incorporated into the Triple-IR fire detector manufactured by SPECTREX.
The result is a unique flame detector which does not produce false alarms,
and at the same time, provides detection over greatly increased distances.
Содержание 20/20MPI
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