Design And Research Of Portable Multi Gas Detector For Cold Storage

Cold storage solves contradiction called "rot in the peak season and lack in the off-season" to a large degree in our country.It is not only provides high quality of nutrition,but extends supply time of fruits and vegetables.It is very important to maintain the normal operation of cold storage by real-time detection of gas composition.Austrian gas analyzer is use in most of traditional test equipment,which has shortcomings as complex operation,poor real-time capability,inconvenient to carry,etc.Cold storage environment has the characteristics of low temperature,high humidity,high fluctuation of gas content and frequent measurement.Most of domestic and foreign research and development of gas detection equipment are for the detection of smoke and combustible gas.There is no multi gas detector which can be used to detect a multi gas of CO₂,O₂,C₂H₄ in the cold storage.Therefore,it is particularly important to develop a high-performance portable multi gas detector for cold storage.On the basis of the existing gas detection technology,a new type of cold storage gas detector is designed and the prototype is made.The main work is as follows:（1）Referred to relevant literatures,comprehended current research status of gas detector and analyzed market demand of gas detector,then put forward the overall design scheme of portable gas detector.（2）Start with the component selection of gas detector,then designed the hardware circuit of portable gas detector,including liquid crystal display module,keyboard module,alarm module,battery management module,USB serial port module,pump driver module,A/D conversion module,signal acquisition and processing module.The flow line was designed according to the shape and size characteristics of the device.（3）Software of control system was designed completely,including LCD screen display,serial port communication,interrupt handling,buzzer,A/D conversion,temperature detection,battery management,pump control,etc.,which can meet the data communication requirements of each module,being continuously collect parameters such as CO₂,O₂,C₂H₄ in real time.At the same time,the pump suction measurement method was adopted to accomplish rapid parameters measurement.（4）PC systems management software was developed which can read 100 historical data and export it in the form of Excel through the data line when the instrument at boot status.Based on the prototype experiments,it is shown that error range and response time performance of the detector can meet the design requirements.Error compensation algorithm and temperature compensation algorithm were studied at the same time in this paper.The results showed that the portable gas detector was rational designed and had strong practicality that would have good popularization value in the aspects such as keeping quality and freshness of fruits and vegetables or sealing food.