Assessing a dryer state using the parameters of a spent drying agent

The paper analyzes the control of regime parameters during grain drying in grain dryers. It has been established that direct monitoring of the heating temperature of grain and its humidity in the dryer column in the grain layer is complicated by the uncertainty of sensor readings placed in the layer, which is caused by a significant difference in the heating temperature of the grain as a thermolabile material and a high-temperature heat carrier. The work considers various methods of preventing fire-hazardous situations and deterioration of grain quality as a result of its overheating by traditional methods by mechanical sampling of grain from a column and measuring its temperature and humidity using dielectric, conductometric or microwave methods of measurement. In order to determine the heating temperature of the grain indirectly by the temperature of the spent drying agent, an installation has been developed. The results of its production tests, the prototype design and technical characteristics are presented. Additional production studies have been carried out to determine the change in the moisture content of grain during the drying process in the grain dryer columns by an indirect method based on the relative humidity of the spent drying agent, as well as laboratory tests on the created testbed. The studies were carried out on wheat grain, grain mixture of wheat and barley, and sunflower seeds. The studies have shown high convergence of results in temperature and good convergence in grain moisture. According to the results of joint mathematical processing of the results of production and laboratory tests, regression equations were obtained for calculating the heating temperature and grain moisture during the drying process using the parameters of the spent drying agent: temperature and its relative humidity.