Three-band infrared flame detector

When a substance burns, it produces smoke and heat, and also produces visible or invisible light radiation that is not found in the atmosphere. Flame detector, also known as photosensitive fire detector, is a fire detector used to respond to the light characteristics of fire, that is, to detect the light intensity of flame burning and the flicker frequency of flame. Infrared flame detector is a flame detector that is sensitive to the longer wavelength infrared light radiation in the flame. According to the different detection bands, it is divided into single band, dual band and three band.

The three-band infrared flame detector (hereinafter referred to as IR3FD) reference design developed by Shijian Company covers the basic functions of infrared flame detectors, providing signal amplification and filtering from the flame sensor, on-chip ADC data acquisition, flexible signal output interface and graphical PC software. Using this platform, customers can quickly evaluate the performance of flame sensors and hardware circuits and shorten the design cycle.

The IR3FD platform uses three flame sensors from the British company Pyreos, covering three wavelength bands of 4.35μm, 4.64μm and 3.91μm respectively. The sensor is a current-type sensor with a built-in transimpedance amplifier that provides a current-to-voltage output. Compared with traditional voltage sensors, this sensor has fast response speed and high sensitivity.

The flame signal is a low-frequency signal, and its energy attenuates sharply with distance in the air. To meet the requirements of the national standard "GB 15631-2008 Special Fire Detector" Class I sensitivity of 25 meters and longer distances, this IR3FD platform uses ADI ultra-low noise The auto-zero precision amplifier ADA4528-2 is used to amplify the flame signal and the ultra-low noise linear regulator ADM7160 provides analog power supply for the flame sensor.

The IR3FD platform provides flexible signal outputs, including standard relay fault and alarm outputs, RS485, RS232, 4-20mA output and USB output. We equip RS485, RS232, 4-20mA and other output ports with ADI digital isolators for isolation protection.

The graphical host computer software of IR3FD provides real-time display, saving and playback functions of multi-channel waveforms for customers to collect and analyze data.

The picture on the right is a physical picture of the circuit board