An optical baffle detector is a device that uses projected light beams to detect smoke over a large area, usually as an indicator of fire. They are used to detect fires in buildings where standard point smoke detectors will become uneconomical or restricted for use by building height. Optical light smoke detectors are often installed in warehouses as a cost-effective way of protecting large open spaces.
Video Optical beam smoke detector
Principle of operation
The optical light smoke detector works on the principle of light blurring, in which the presence of smoke blocks some of the light from the jets, usually through absorbance or light scattering. Once a certain percentage of the transmitted light has been blocked by smoke, fire is signaled. Optical light smoke detectors are commonly used to detect fires in large commercial and industrial buildings, as components in larger fire alarm systems.
Maps Optical beam smoke detector
Design
The optical light smoke detector consists of at least one light transmitter and one receiver, which is photosensitive. The photosensitive receiver monitors the light generated by the transmitter under normal conditions. In the absence of smoke, light moves from the transmitter of light to the receiver in a straight line. In fire, when smoke falls on the path of a light detector, some light is absorbed or dispersed by smoke particles. This creates a decrease in the received signal, which leads to an increase in optical blurring ie the transmission of light along the emission line.
End-to-end
End-to-end optical smoke smoke detector is a system that has a separate light transmitter and receiver. They are used in applications where there is little space available to install a wide detector - because the receiver is on a separate element each individual unit is small enough. The small detector size is also an advantage for aesthetic installation, where fire protection is required without introducing unsightly or blatant modern devices. Aesthetic considerations are essential for cultural and heritage sites. The end-to-end detector includes an open-air smoke imaging detector, where two wavelengths of light are used to detect smoke. UV and IR wavelengths of light react to smoke differently, and comparative differences help verify real smoke by comparing reflections and seeing differences in profiles. UV and IR respond identically to things like clogging (ladder up front to detector lane), bug (block block), fog, steam, and other things that normally cause false alarms, so both wavelengths of light are used together to detect smoke accurately..
Reflective
The reflective optical reflective smoke detector incorporates a light emitter and a detector on the same unit. The light path is made by reflecting light emitted from the transmitter of the retroreflector placed opposite the detector.
Motor
The motorized optical motor smoke detector automatically aligns itself during installation and can compensate for 'drift' alignment in which the optical path of the ray changes over time. Both end-to-end systems and reflective systems can be motorized.
Limitations
Early examples of optical light smoke detectors are susceptible to false alarms, caused by many different factors. Most commonly, the buildup of dust, dirt and other debris will lower the detection threshold for the detector, causing the system to enter the alarm when no flame is present. Modern devices use automatic reinforcement controls as a means to adapt signals to this effect. Building movement is another common problem, where the movement of buildings causes the optical smoke detector to lose alignment. Motorized ray detectors have partially addressed this problem, but can still be problematic in certain installations.
See also
- Smoke smoke detector
- Automatic fire suppression
- Carbon monoxide detector
- Fire alarm
- The fire sparkler
- Flame detector
- Gas fire suppression
- Manual call point
- Passive infrared sensor
- Smoke detector
References
Source of the article : Wikipedia
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