干燥过程中谷物水分在线测量系统  

An On line Measurement and Monitoring System of Grain Moisture during Drying Process

作　　者：程卫东[1] 柏雪源[2] 王相友 申晋[4] 

机构地区：[1]山东工程学院设备及自动化系,淄博市255012 [2]山东工程学院科学技术研究院 [3]中国农业大学,北京市100083 [4]山东工程学院电气技术学院

出　　处：《农业机械学报》2000年第2期53-55,共3页Transactions of the Chinese Society for Agricultural Machinery

基　　金：农业部重点科研项目! (项目编号 :97农机 0 2 0 3 )

摘　　要：讨论了以由谷物含水量 (介质介电常数 ε)变化引起电容式传感器振荡频率的变化来测量谷物水分的方法。采用同心圆式电容传感器对谷物干燥设备进行在线水分测量及控制 ,建立了定流量条件下谷物水分同电容传感器振荡频率。The objective of this study is to develop an on line measurement and monitoring system of grain moisture used in drying process of continuous type of dryer. Grain moisture content can be indirectly measured by sensing the dielectric constant of grain. The dielectric constant of grain is mainly affected by the moisture content, as well as other factors such as: temperature, density and variety of grain. A concentric cylinder type of capacitance sensor is designed, fabricated and tested for measuring grain moisture content under various conditions. In the measuring circuitry, the changes of moisture content is firstly converted into changes of dielectric constant and finally converted into changes of oscillation frequency. The relationship between grain moisture content and the sensor oscillation frequency as well as grain temperature under uniform grain flowrate was determined and a mathematical model was then developed. In order to obtain the required grain moisture content, the PI control algorithm is used to control the unloading augur speed. The experimental result shows that the control accuracy of moisture content at the outlet is not more than 0 5%.

关 键 词：电容传感器 谷物干燥机 水分在线测量系统 

分 类 号：S226.6[农业科学—农业机械化工程] TP212[农业科学—农业工程]