Siemens Schweiz Ag

Thomas Rohrer

Martin Fischer

Matthias Stutz

Various embodiments may include fire detector comprising: a fire sensor generating a signal corresponding to a characteristic fire parameter; a control unit; and a photodiode for detecting ambient light in a spectrally delimited range of 400 nm to 1150 nm. The control unit analyzes the signal and generates a fire alarm if the signal corresponds to a predetermined threshold for a fire. The control unit analyzes a photo-signal received from the photodiode and if the flicker frequencies characteristic of open fire are detected, the control unit increases a sampling rate for acquiring the sensor signal from the fire sensor by reducing a filter time of an evaluation filter for the fire analysis and/or by lowering an alerting threshold.

Fire detector having a photodiode for sensing ambient light

An open-type scattered light smoke includes a housing shell supporting a circuit substrate having at least one light emitter and one light receiver arranged thereon. The light emitter and the light receiver are arranged in a scattered light array having a scattered light volume located in the open air outside the smoke detector. The light emitter emits a light beam having a direction pay, with part of the path traveled by the directional ray between the light emitter and the scattered light volume running parallel to an outer face of the circuit substrate facing away from the housing shell. The light emitter may be an LED housed in a sidelooker package and the light receiver may be a photodiode housed in a reverse-gullwing package. A sensor surface of the photodiode is aligned opposite the scattered light volume through an opening in the circuit substrate that provides mechanical protection.

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Sachseln, Switzerland

Thomas Rohrer