MODULATION COMBUSTION SENSOR Russian patent published in 2014 - IPC G08B17/12 

FIELD: fire-prevention facilities.

SUBSTANCE: invention relates to fire-fighting equipment and can be used to detect combustion. The modulation combustion sensor comprises an optical system 1, a modulator 3 with a fixed 4 and mobile 5 reticle gratings with electromechanical oscillator 2. Each reticle grating of the modulator 3 has one zone of modulation of the optical signal. The optical system 1 comprises a source of optical test signal 8 and is made so that at its output there are two signals: the test signal and the controlled space signal, which are separated in space and are not mixed. The parameters of reticle gratings 4, 5 are selected so that per one period of motion of the mobile reticle gratings 5 the optical flow of the controlled space is consistently overlapped and is opened for passing through the modulator 3. In the time interval corresponding to the overlapping of the optical flow of the controlled space to the photodetector 6, the switching on of the test source 8 for a short period of time is carried out with the help of signal processing circuit 7. The optical signal is converted by the photodetector 6 into the electric signal in the form of two pulses: the amplitude of the first pulse corresponds to the signal of the controlled space, and the amplitude of the second pulse - to the test signal. Thus, due to the construction of the reticle gratings and the signal processing circuit 7 at the input of the photodetector 6 only one optical signal may exist: either the test or the signal of the controlled space.

EFFECT: increased sensitivity of the sensor and decrease of power consumption.

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