Microwave drying control system based on dielectric property dynamic change

Abstract

The invention relates to a microwave drying control system based on a dielectric property dynamic change. A dielectric property dynamic change value of a material is monitored by pre-inputting a mathematical model so as to improve the quality the fruits and vegetables and medicinal materials of different batches and varieties after microwave drying. The whole process is as follows: firstly inputting a mathematic relation model of a dielectric constant, a dielectric dissipation factor and water and temperature distribution of the material at a certain frequency before microwave drying, and establishing a mathematical model library of the dielectric constant and the dielectric dissipation factor changing with temperature and water; performing online monitoring on the dynamic change value of the dielectric property in the microwave drying process by means of online real-time monitoring of water and temperature; and controlling the microwave drying process to optimize the drying quality of the material by integrally analyzing influence of the dielectric property, water and temperature on the drying process, wherein negative effects such as charring in the drying process is avoided.

Description

technical field [0001] The invention relates to the technical field of drying fruits, vegetables and Chinese medicinal materials, in particular to a microwave drying control system based on dynamic changes in dielectric properties. Background technique [0002] In recent years, there have been some researches on microwave drying of agricultural products in the world, and domestic related researches are also increasing year by year. Reiner Ihns et al. studied the drying process of two kinds of apricot fruits at different temperatures, compared the drying curves, chromaticity changes, nutritional components and energy consumption of constant-speed drying and reduced-speed drying, and concluded that the former had slightly lower energy consumption. In the latter, the chromaticity becomes worse with the increase of drying temperature [1] . Xu Mingliang and others compared the effects of different drying methods on the quality of dried sea asparagus, and found that the color an...

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Problems solved by technology

The above drying methods, no matter whether they have monitoring and control or not, lack direct consideration and control of material quality during the drying process. Although the drying rate and energy consumption can be controlled to a certain extent, the drying quality is completely uncontrollable. There is no optimized drying system specially designed for microwave drying, and the optimization in consideration of dynamic changes in dielectric properties is completely blank

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