Study On Material Internaltemperature Test System And Distribution During Combined Drying

Drying is the common method to prolong fruit and vegetable storage period. Ingeneral, traditional drying cycle is so long that products can’t be able to content withthe increasing demand and the health assurance is also not reliable. With developmentof new drying technology industries, also the more and more applications try to use infruit and vegetable drying.Temperature has a big influence on the drying process and dry products. Themeasurement of temperature variation and temperature distribution can control dryconditions, ensure the reasonable drying technology and dry switching point betterduring drying process. As well as provide conditions for studying internal materialheat and mass modeling during drying process.In this paper, a heat pump-hot air combination dryer is design and a set of dataacquisition surveillance system is developed based on virtual instrument. The mainworks is as follows:（1）Learn the technology and equipment of dry and the advanced combinationdrying, through the review of the literature; as well as the research and application ofmonitoring system based on LabVIEW which is the common develop software ofvirtual instrument.（2）According to the combination dry principle and equipment as thefoundation, select heat pump-hot air dry technology and design a heat pump-hot aircombination dry tester.（3）Familiar with the construction of the data acquisition system based onvirtual instrument, develop a monitoring system using LabVIEW combined withefficient data acquisition card and other hardware, to real-time monitor temperature ofmaterial internal point in dry process.（4）Select typical fruit and vegetable as the sample subjects, complete schemedesign of combination dry experiment and the arrangements for experiment operation.According to the experimental result, analysis temperature variation trend at every point of material during dry process, and understand temperature has influence on thedry rate, product quality and so on.The measurement of temperature variation and temperature distribution cancontrol drying conditions, ensure the reasonable drying technology and dry switchingpoint better during drying process. As well as provide conditions for studying internalmaterial heat and mass modeling during drying process. This paper developedmonitoring system not only can be used in monitoring temperature in fruit andvegetable drying process, but also accumulate experience for develop othermonitoring devices.