Design And Implementation Of High Accuracy,High Reliability And Wide Spectrum Flame Detector

In real life,the burning of flammable substances such as grease,gas and metals often occurs.Once this happens,the consequences are not just simple fires,but irresistible deflagrations and explosions.Flame detectors are the most basic and important components in automatic fire alarm and suppression systems.In view of the long response time of existing flame detectors and the poor anti-false alarm performance,it cannot meet the needs of fire extinguishing and explosion suppression.A purple infrared flame detection device with high accuracy and high reliability is designed.The detector uses a three-probe design with a UVsensitive tube(185-260 nm)and a dual-infrared photosensitive tube(2.7 ?m,4.35 ?m).It has an ultra-fast time response(? 2 ms@0.4 m standard fire)and a large field of view(110 °),high reliability,long life and other advantages.In this paper,a high-precision ultraviolet sensor and a dual-band infrared sensor are used to expand the detection range of the flame spectrum.In order to achieve high-precision detection of the flame signal,a real-time temperature adjustment circuit is added to the signal acquisition circuit.By changing the real-time reference voltage in order to reduce the influence of temperature drift,the accuracy of flame detection is achieved;in order to achieve high reliability of the hardware circuit,the overall circuit board is optimized during the design,and the four-layer circuit board design is used to effectively power and ground isolation,which isolates analog signals and digital signals,reduces crosstalk of hardware circuit signals,and improves the overall reliability of the hardware circuit.In the software design,a single UV logic trigger and purple infrared logic trigger algorithm design is used.The single UV trigger logic uses the fast response characteristics of the UV sensor to realize the rapid detection of largearea and close-range flames.The threshold value is used as the trigger logic,and then the flame characteristic information is compared to determine whether to output a pre-alarm signal.The purple infrared logic trigger is to use the three infrared probes to work together to determine the flame signal of small and medium strength.When the ultraviolet threshold is met,next,it is necessary to carry out dual infrared logic judgment and feature comparison to realize flame discrimination.In order to improve the response speed under the conditions of small and medium-sized flames,the program design uses a high-order derivative of the data acquired by dual infrared to improve the sensitivity of purple infrared logic triggering.The reasonable and effective combination of software design and hardware circuit realizes the optimized design of purple infrared flame detector with high reliability,low false alarm and fast alarm.The purple infrared flame detector designed in this paper is oriented to practical applications and has the ability to prevent multi-factor interference.It can effectively eliminate false alarms caused by non-flame radiation such as sunlight and various artificial light sources,and solve the false alarms that have always existed in photosensitive flame detectors,at the same time,it has the ability of quick alarm.After actual testing,the main indicators of the detector have reached the domestic leading level,which can meet the needs for fire suppression and explosion suppression in the fields of combustion monitoring,fire self-alarm,and oilfield,mine,petrochemical and other industries.