When smoke is present, part of the infrared ray is absorbed when it encounters the
smoke particles, while another part is scattered by smoke particles. The rest
reaches the reflector and is returned to the receiver. The infrared ray is attenuated
further. Only a small part of the infrared ray initially transmitted reaches the
receiver, and the electrical signal becomes weaker.
Figure 2: Function of the linear smoke detector with smoke
1 Absorption 4 Smoke particle
2 Scattering 5 Infrared ray
3 Attenuated infrared ray
The linear smoke detector measures the distance, which enables an exact
alignment of the smoke detector to the reflector when the detector is
commissioned.
Due to distance measuring, the smoke detector recognizes when the measuring
section is crossed by a reflecting object. In this case, the smoke detector sends a
fault signal to the control panel.
2.2.1 Infrared ray
Setup of the infrared ray
The infrared ray is scattered, giving it a conical shape. The radiation energy
decreases outwards. The infrared ray is divided into the following three ranges:
Structure and function
Overview
2
A6V10332811_e_en_-- 7 | 44
To Next Page
Loading...
