| 摘要 |
A testing and calibration device is provided for a known type of electrical instrument for measuring moisture in a grain sample. The instrument comprises a sample-receiving test cell in the form of a cylindrical container having a concentric electrode therewithin and operates on the principle that the intensity of an electrostatic field in the test cell changes in proportion to the amount of moisture in the grain sample. The testing and calibration device, which serves as synthetic sample or substitute for a controlled grain sample of known size, dielectric constant and moisture content, comprises concentrically arranged inner and outer cylindrical dielectric members defining a sealed cylindrical space therebetween which contains a metal component of appropriate size and shape and sufficient liquid added during manufacture to duplicate the electrical characteristics of the controlled grain sample. The liquid may take the form of water or a mixture of water and an antifreeze agent. A thermometer is embodied in the device to provide ambient temperature information sometimes required for test purposes.
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