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United States Department of Agriculture

Agricultural Research Service

Title: Performance of a Commercially Available Microwave-based Bale Moisture Content Meter

Authors
item Delhom, Christopher
item Byler, Richard

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: December 20, 2007
Publication Date: July 1, 2008
Citation: Delhom, C.D., Byler, R.K. 2008. Performance of a Commercially Available Microwave-based Bale Moisture Content Meter. National Cotton Council Beltwide Cotton Conference. Nashville, TN. CD ROM pp 753-758.

Interpretive Summary: In 2006 the Farm Service Agency defined cotton bales with excessive moisture as those with mc greater than 7.5%, wet basis, at the gin. Excessive moisture can lead to deterioration of lint quality. The deterioration of lint quality in the bale would harm the domestic cotton production market by making US cotton less desirable on the world market. Therefore it is important for gins to assure themselves that the bale mc is no higher than 7.5%. A non-contact microwave-based meter, Vomax 851-B, has been commercially available but independent verification of these measurements has not been available. The commercial meter scans across a cross-section of the bale and provides an average reading of bale moisture content. Holly Ridge Gin Company provided access to the commercial meter installed in their facility. A two part study was conducted to assess the measurements provided by the commercial meter. In the first part cotton bales were prepared by the Cotton Ginning Research Unit for measurement on the commercial instrument as well as by the oven reference method. The effect of bale orientation and bale packaging was also studied with these samples. The bales by the Cotton Ginning Research Unit were produced with two different drying schemes to provide for a range of bale moisture contents, these bales were also thoroughly sampled for oven reference method samples. The second part of the study collected samples from 50 bales at the commercial gin, over 5 days, during the 2007 ginning season. The collected bale samples were tested by the oven reference method for moisture content and those readings were compared to the microwave-based meter readings for moisture content. Bales were tested with a moisture content ranging from 4.2% to 7.2 %, wet basis. The Vomax measurements tracked variation in bale moisture content; however the factory calibration tended to predict higher moisture content than determined by the oven method.

Technical Abstract: Measuring the moisture content of cotton bales has been a topic of intense interest in the last few years. In 2006 the Farm Service Agency defined cotton bales with excessive moisture as those with mc greater than 7.5%, wet basis, at the gin. Therefore it is important for gins to assure themselves that the bale mc is no higher than 7.5%. A non-contact microwave-based meter, Vomax 851-B, has been commercially available but independent verification of these measurements has not been available. The Vomax meter provides an average reading of bale moisture content by averaging multiple scans of cross-sections of the bale. A two phase study was conducted to independently assess the measurements provided by the commercial meter. For the first phase of study bales were prepared by the Cotton Ginning Research Unit for measurement on the commercial instrument as well as by the oven reference method. The effect of bale orientation and bale packaging was also studied with these samples. In the second phase samples were collected from 50 bales, over 5 days, during the 2007 ginning season. The collected bale samples were tested by the oven reference method for moisture content and those readings were compared to the microwave-based meter readings for moisture content. Bales were tested with a moisture content ranging from 4.2% to 7.2 %, wet basis. The Vomax measurements tracked variation in bale moisture content; however the factory calibration tended to predict higher moisture content than determined by the oven method.

Last Modified: 11/24/2014
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