Ecotech GTS RIV-601F, Руководство по применению, Страница: 4 / 28

rev. 0 NOV11
MAFP 3-GB
INFRARED
LIGHT
radiation intensity
wavelength
WHY IT DOES NOT RESPOND TO THE SUNLIGHT AND LAMPS
Sun and lamps also generate thermal infrared radiation.
But flame is different because it flickers at a particular frequency in the
range from 3 to 30 Hz (pulses per second).
The IR flame detector is tuned to this pulsing radiation like a radio
receiver is tuned to one station and ignores all others.
Nevertheless direct exposition to the sunlight and lamps must be
avoided, since it causes the detector to become blind or give false
alarms.
amplitude
time
WHY IR (infrared) RADIATION
The visible radiation emitted by fire is just a small amount of the
emitted energy.
The most part is comprised of invisible thermal infrared radiation,
typically emitted by all hot bodies, with a wavelength varying with the
body temperature.
D
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IR FLAME DETECTOR
RIV-601P/F
General notions
The IR flame detector model RIV-601P/F is an electronic optical fire
detector device that responds immediately to the thermal infrared
radiation emitted by fire, and is tuned to the pulse frequency of the
flame to ignore sun, lamps and other light and infrared radiation
sources.
WHY IR (infrared) FLAME DETECTOR
Eye is faster than nose. In the event of live fire the IR flame detector
responds immediately. Its behaviour is similar to that of the eye. In
fact it “sees” the radiation emitted by fire, and its sensitivity is inside a
cone of 90° which is called the field of view.
The minimum flame size that can be detected by the RIV-601P/F
varies with the distance. It doubles at double distance and is half at
half distance. The sensitivity value is 2-3% of the distance.
For example, at 10m the smallest detectable flame size is 20-30cm.
At higher temperature a shorter wavelength is generated and
viceversa. The IR flame detector sees very well this IR radiation but is
near blind to the visible light.
Furthermore the thermal infrared radiation passes through the smoke,
while the light does not.
For this reason the IR flame detector responds to the fire also when
smoke is present.
Pulse frequencies
FIELD OF VIEW
Flame radiation spectrum