Key Technologies Of Period Verification Method For Tobacco Moisture Meter

At present,the TM710 E infrared moisture meter made by NDC Technologies Inc.is mainly used to monitor the moisture content of cut tobacco.In order to ensure the accuracy of the measurement results of the infrared moisture meter,the factory usually checks the measurement results of the infrared moisture meter through the standard oven method.This paper studies the key technologies of period verification for infrared moisture meter by microwave transmission method and rapid drying method.(1)Study on the method of measuring the moisture content of tobacco based on microwave transmission method.Based on the measurement principle of microwave transmission method,the mathematical model is derived and the influence factors are analyzed.Single-factor experiments are conducted using the RH2010 SF microwave measuring instrument.Experimental results show that sample quality and anhydrous ethanol content affect greatly,and the moisture content measurement result is most distinguish when the anhydrous ethanol is 3.6 mL and the tobacco sample is 0.42 g.The relationship equation between the microwave voltage value(average value)and the moisture content is established,and the determination coefficient is 0.994;It is proved that microwave transmission method can measure moisture content,but it can’t be measured precisely.(2)Study on the rapid drying method for measuring the moisture content of tobacco.According to the measurement requirements for the infrared moisture instrument,a rapid drying method for measuring the moisture content of tobacco is designed.Single-factor Experiments are carried out with a HE53 halogen moisture meter made by Mettler Toledo.Experimental results show that the most stable measurement result is obtained when at a tobacco quality of 5 g,at a temperature of120 °C,and with the tobacco intact.Repetitive experiments under the condition of moisture content of about 10%-50% are conducted,the results of which are compared with the standard oven method.The experimental results show that the measurement results base on the rapid drying method have a standard deviation within 0.5%,which shows a better stability than the results from the standard oven method.(3)Study on the method of period verification of the moisture content of tobacco based on rapid drying method.With the moisture content measurements obtained by the rapid drying method and the standard oven method,an error correction model of period verification measurement of the moisture content is established,with a linear error of 2.3% for moisture content in the range of 10%-50%.In order to improve the measurement efficiency,the moisture content prediction models based on K-nearest neighbor(KNN)prediction algorithm and regression equation are studied.And the results show that the KNN prediction algorithm has better prediction results,with the minimum error within 0.2%.Thus,the error synthesis result of period verification of the moisture content based on rapid drying method is 0.35%,which meets the requirement of period verification.