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United States Department of Agriculture

Agricultural Research Service

Title: Moisture-Sensing Tool and Technique
See also: US Patent Office Full Record


Patent Number: 6691563
Docket Number: 19699
Serial Number: 9829966
Date Patented: 02/17/2004

Technology Description:

This invention provides a way to accurately determine moisture content in natural and manufactured granular materials with a single calibration equation. This dielectric method uses very low power levels at microwave frequencies and does not change the material properties. It is sensitive to water content, regardless of the type of dielectric material. Dielectric methods are commonly used for rapidly, nondestructively measuring moisture content in cereal grains and other agricultural products. It is used in other industries such as the food, lumber, chemical, pharmaceutical, and construction industries. When dielectric methods are used for sensing moisture content in granular materials, an individual calibration equation is required for each particular material. This is mainly related to size, geometry and differences in particle composition. ARS’s method uses a single calibration equation. This invention responds to a need in highly automated industries where moisture content has to be determined accurately on a continuous basis. Existing on-line systems need separate calibrations for different materials. This invention should result in a cost-effective, universal microwave moisture meter with incredible commercial potential. Moisture information is important in determining grain yields, prices, and the need for drying grains for safe storage. This invention could result in cost savings depending on the industry and commodity.

Many industries can use this technology including agricultural (particularly the grain industry), food, lumber, pharmaceutical, chemical and construction industries. Investment by companies in such equipment should optimize operations, resulting in cost savings.


Please refer to USPN 6,691,563 (Docket #0196.99), "A Universal Dielectric Calibration Method and Apparatus for Moisture Content Determination in Particulate and Granular Materials," which issued on February 17, 2004.  Foreign rights are not available.


Stuart O. Nelson
Quality Assessment Research
Athens, Georgia 30604
(706) 546-3101 / Fax: (706) 546-3607
Andrzej W. Kraszewski (retired)

Samir Trabelsi
(Formerly with ARS)




Last Modified: 10/1/2015
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