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Each
detector listed below is available in three versions:
• a
standard version
• a version with an LED which flashes
continuously in quiescent mode
• a version with both a
flashing LED and a magnet-operated test switch (reed relay)
Ionisation
Smoke Detector
Air in the
dual sensing chambers is irradiated to produce ions that
travel to the positive and negative electrodes, creating
a current flow. As smoke enters the outer chamber, the
flow drops and the voltage increases. The detector will
then enter the alarm state and the indicator LED lights
up.
An
intergrating ionisation detector, suitable for
use in areas where transient high levels of smoke may be
expected, is also available.
For
important technical information regarding
sensitivity to air movement, please
click here.
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Optical
Smoke Detector
The optical smoke detector uses an
internal pulsing LED and a photo-diode at an obtuse
angle. In the event of smoke entering the chamber, the
light pulse from the LED will be scattered and
registered by the photo-diode. The detector will then
enter the alarm state and the indicator LED lights
up.
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Heat
Detector
The heat
detector operates by using a matched pair of thermistors
to sense heat. One thermistor is exposed to the ambient
temperature, the other is sealed. In normal conditions,
the two thermistors register similar temperatures, but,
on the development of a fire, the temperature recorded
by the exposed thermistor will increase rapidly,
resulting in an imbalance of the thermistors and causing
the detector to change to the alarm state.
A1R,
BR and CR are Rate of Rise detectors, designed to
detect a fire as the temperature increases, but they
also have a fixed upper limit at which the detector will
go into alarm if the rate of temperature increase has
been too slow to trigger the detector
earlier.
CS
detector is a fixed heat detector which only
changes to the alarm state at a preset
temperature. |
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Bases
The bases
have been designed to enable detectors to be plugged in
without any need for force and have a "one way only"
fit.
The
standard base contains no electronic parts which could
be damaged during installation.
Relay Bases
Several types
of relay base are available: an auxiliary relay base and
two types of EOL (End-of-Line) relay bases designed for
circuits with supply voltages of between 9 and 18V DC
and 16 and 33V DC. |
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