Flame detector, also known as photosensitive fire detector, is a fire detector that detects the intensity of flame burning and the frequency of flame flicker. This article introduces the working principle of flame detector.
The ultraviolet, visible and infrared radiation released by the flame combustion process are different from other interfering radiations and have typical characteristics at specific wavelengths and specific flicker frequencies (0.5HZ-20HZ). The ultraviolet and infrared radiation of sunlight, hot objects and electric lamps have no flicker characteristics.
The working principle of the flame detector is to detect the flame by detecting the special wavelengths of ultraviolet, infrared and visible light emitted by the flame and identifying the characteristic flicker frequency of the flame. Ultraviolet photodiodes, ultraviolet detectors and ultraviolet sensors are commonly used detection elements.
Ultraviolet detectors are sensors that convert one electromagnetic radiation signal into another form that is easy to receive and process. Photoelectric detectors use the photoelectric effect to convert light radiation into electrical signals. The photoelectric effect can be divided into external photoelectric effect and internal photoelectric effect.
External photoelectric effect devices usually refer to photosensitive electric vacuum devices, which are mainly used in ultraviolet, infrared and near-infrared bands. External photoelectric effect devices with internal gain include photomultiplier tubes, image intensifiers and other photosensitive vacuum devices. They have high sensitivity. They can convert very weak light signals into electrical signals and perform single photon detection. Their sensitivity is several orders of magnitude higher than that of semiconductor devices with internal electro-optical effect.
The internal photoelectric effect can be divided into photoconductive effect and photovoltaic effect. In the photoconductive effect, after absorbing enough energy photons, the semiconductor activates some electrons or holes from the original non-conductive binding state to the free state of conductive energy, which leads to an increase in semiconductor conductivity and a decrease in circuit resistance. In the photovoltaic effect, the photogenerated charge generates a small P-N potential difference at the semiconductor junction. The generated photovoltage is amplified by the photoelectric device and can be directly measured. Devices based on the photoconductive effect and the photovoltaic effect are called semiconductor photoconductive detectors and photovoltaic detectors, respectively.
Flame detector, also known as photosensitive fire detector, is a fire detector that detects the intensity of flame burning and the frequency of flame flicker. This article introduces the working principle of flame detector.
The ultraviolet, visible and infrared radiation released by the flame combustion process are different from other interfering radiations and have typical characteristics at specific wavelengths and specific flicker frequencies (0.5HZ-20HZ). The ultraviolet and infrared radiation of sunlight, hot objects and electric lamps have no flicker characteristics.
The working principle of the flame detector is to detect the flame by detecting the special wavelengths of ultraviolet, infrared and visible light emitted by the flame and identifying the characteristic flicker frequency of the flame. Ultraviolet photodiodes, ultraviolet detectors and ultraviolet sensors are commonly used detection elements.
Ultraviolet detectors are sensors that convert one electromagnetic radiation signal into another form that is easy to receive and process. Photoelectric detectors use the photoelectric effect to convert light radiation into electrical signals. The photoelectric effect can be divided into external photoelectric effect and internal photoelectric effect.
External photoelectric effect devices usually refer to photosensitive electric vacuum devices, which are mainly used in ultraviolet, infrared and near-infrared bands. External photoelectric effect devices with internal gain include photomultiplier tubes, image intensifiers and other photosensitive vacuum devices. They have high sensitivity. They can convert very weak light signals into electrical signals and perform single photon detection. Their sensitivity is several orders of magnitude higher than that of semiconductor devices with internal electro-optical effect.
The internal photoelectric effect can be divided into photoconductive effect and photovoltaic effect. In the photoconductive effect, after absorbing enough energy photons, the semiconductor activates some electrons or holes from the original non-conductive binding state to the free state of conductive energy, which leads to an increase in semiconductor conductivity and a decrease in circuit resistance. In the photovoltaic effect, the photogenerated charge generates a small P-N potential difference at the semiconductor junction. The generated photovoltage is amplified by the photoelectric device and can be directly measured. Devices based on the photoconductive effect and the photovoltaic effect are called semiconductor photoconductive detectors and photovoltaic detectors, respectively.