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Structure and function
Setup
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Building Technologies
A6V10367521_h_en_--
Fire Safety
2015-02-02
Setup of the point detector
The point detector OOH740-A9-Ex has two optical and two thermal sensors.
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1 Heat sensors
3 Forward scatterer
2 Backward scatterer
4 Labyrinth
The detector has a sophisticated opto-electronic measuring chamber with two
optical transmitters, an optical receiver, and two thermal sensors.
The transmitters illuminate the smoke particles from different angles. One sensor
acts as forward scatterer, the other as backward scatterer. The scattered light then
hits the receiver (photodiode) and generates a measurable electric signal.
The combination of a forward and backward scatterer facilitates an optimum
detection and the differentiation of light and dark particles, which leads to a
homogenous response behavior and optimizes the differentiation of wanted signals
and deceptive phenomena.
In addition, the heat sensors make it possible to detect fires without smoke
generation.
The combination of optical and thermal sensor signals optimizes detection
reliability. This has the following advantages:
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Early detection of all types of fire, whether they generate light or dark smoke, or
no smoke at all.
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The multisensor fire detector can be operated at a lower sensitivity level and
thus achieves a higher immunity against false alarms, which can be caused by
cold aerosols (e.g., by smoking). In the case of an open fire, the smoke
sensitivity is heightened by the temperature increase, which means that a
detection reliability level that is comparable to that of the wide-spectrum smoke
detector can be achieved.
The detector can also be used purely as an optical smoke detector or purely as a
heat detector. This is determined by selecting one of the following sensor modes:
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Sensor mode 0: Application as neural fire detector
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Sensor mode 1: Application as heat detector
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Sensor mode 2: Application as smoke detector
See also
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