The Characteristics Of Infrared Heating Drying Under The Condition Of Vacuum

This paper mainly studied the application of infrared heating drying technology in vacuum conditions. Summarized the infrared heating drying principle, the drying characteristics of drying technology and its research development, analyzed the advantages of infrared heating drying under vacuum conditions, on the basis of studying the principles of infrared heating drying and vacuum drying, and comparing it with the traditional drying technology. Comparison shows that infrared heating drying technology under the condition of vacuum has the following advantages, such as high drying efficiency, good quality of products, high heat energy utilization, environmental pollution-free, simple structure of drying equipment, wide application prospect in the market.Through the design and manufacture, the original vacuum belt drying equipment has been converted into vacuum infrared drying equipment, which is needed by research. The distance between infrared transmitter and the distance between infrared radiator and the dry material can be adjusted by sliding the active casings which on the infrared lamp holder, for studying the characteristics of infrared heating drying under a vacuum condition provides a reliable guarantee.The paper gives the definition of "vacuum condition". Using FLUENT software to simulate the vacuum conditions within experimental equipment under different vacuum degree, and analyzed the pressure distribution and gas flow velocity in the equipment affected by vacuum degree changing. Using temperature sensor to measure the temperature of loading plate within the experimental equipment, and analyzed the temperature of parcel shelf was affected by vacuum degree changing. Studies have shown that the lower the vacuum degree, pressure distribution is uneven in equipment; the higher vacuum degree, the greater the gas flow velocity in the equipment; the higher vacuum degree, the higher the temperature of the loading plate.This paper analyzed the internal factors and external factors of the drying process of infrared heating drying under the condition of vacuum. With the pumpkin pulp as a material, doing the experiment of infrared heating drying under the condition of vacuum, studied the dynamics of the drying process. Experiment mainly studied the input power of infrared heating tube (450,500,550,500W), the thickness of the material (1,2,3 mm) and vacuum degree (0.01,0.03,0.05, 0.1MPa) influence on drying characteristics. Research shows that the higher the input power of infrared heating tube, the faster the drying rate, which is 600W>500W>550W>450W; the thinner the material thickness, the faster the drying rate, which is 1mm>2 mm>3mm;the higher the vacuum degree, the faster the drying rate, that is, 0.01MPa>0.03MPa>0.05MPa> 0.1MPa.In order to control product quality, optimizing the drying process, studied the dryingkinetic model of infrared heating drying under the condition of vacuum. This paper used four groups of experimental data which under the condition of vacuum 0.01MPa, fabric thickness 2mm, the input power is respectively 450w,500w,550w,600w for the experimental samples, obtains its water than MR, and using the nonlinear regression function of Matalab 2009a software, doing nonlinear regression fitting between the MR curve and 10 kinds of different drying kinetic model, the suitable drying kinetic model of Infrared heating drying under the condition of vacuum was obtained, and determined the drying constant of the drying kinetic model, set up the precise drying kinetic model of infrared heating drying under the condition of vacuum.