1. Direct drying method

Direct drying method: 符合ASAE标准, 将样品放入烘烤箱中, 把它放在烤箱里 19 130℃ 小时; 测量体重减轻, IE。, 水分含量.

2. Capacitance method

Capacitance method: 水分的电常数远大于谷物中其他成分的电常数, 水分含量的变化必然引起电容的变化. 通过测试样品湿度变化对应的电容变化, 可测试谷物的水分含量.

3. Infra-red heating drying method

Infra-red heating drying method uses infra-red light to heat the sample and remove the moisture, so as to test the moisture content. The main influencing factors are temperature and heating time. Online testing is not applicable for this method.

4. Microwave heating method

Microwave heating method uses the 2450MHz or 915MHz ultrahigh frequency microwave produced by microwave oven’s magnetron to oscillate the water molecules rapidly in order to make the molecules impact and rub each other and then remove the moisture in grain.

5. Ray method

Near infrared reflectance spectroscopy (NIRS) was first used in grain moisture testing in 1964. As different molecules have different features of absorption for near infra red lights of different wave lengths, when near infra red light (wave length 1940nm) is exposed to sample, light intensity of diffuse reflection is related to sample’s component content, in conformation with Lambert-Bill Law.

6. Micro wave absorption method

Micro wave absorption method started from 1840s. Moisture is tested indirectly by inspecting the absorption of micro wave energy by moisture or the change of parameters along with moisture like micro wave cavity resonant frequency and phase position.