Abstract
The digital moisture meter includes means for taring an empty sample pan placed on the balance platen. After the balance has been tared, a small sample is placed in the sample pan and a heat lamp energized. At this same time, the initial weight of the sample is stored in memory and after twenty seconds a first calculation is made to determine the percent weight loss, the value of which is also stored in memory. Subsequent percent weight loss values are calculated and if the latest percent weight loss is greater than the one that has been stored in memory, the stored one is then replaced with the latest value. However, if the latest percent weight loss value is less or equal to the stored value, the stored value is retained in memory for comparison with the next percent weight loss value that is calculated. When the percent weight loss value remains constant for a predetermined number of checks, the stored percent weight loss that has remained constant is then considered to be...
Patent number: 4316384Filing date: Sep 4, 1979
Issue date: Feb 23, 1982
Inventors: Dennis L. Pommer, Paul E. Coleman
Assignee: General Mills, Inc.
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What is claimed is:
1. A digital moisture meter comprising a balance including a platen for receiving a sample thereon and means for providing a digital signal having a value in accordance with the initial weight of the sample on said platen and also successive later digital signals having digital values representative of later reduced weights of said sample, means for heating said sample to remove moisture therefrom, means for reducing the intensity of said heating means after a predetermined time interval, first means for storing said digital signal having a value representative of the initial weight of said sample, second means for storing said later digital signals having a value representative of a subsequent reduced weight, each of said later digital signals being successively stored in said second storing means, calculating means responsive to the value of said digital signal stored in said first storing means and the value of said digital signal stored in said second storing means at a given time for providing a digital signal having a value representative of the percent weight loss for each successively stored later digital signal, third means for storing one of said digital signals having a value representative of percent weight loss, fourth means for storing a later digital signal having a value representative of a later percent weight loss, means for comparing the value of said one digital signal stored in said third storing means with the value of the digital signal stored in said fourth storing means and for substituting the digital signal stored in said fourth storing means for the one stored in said third storing means if greater in value than the one already stored in said third storing means, means for displaying the value of said digital signal stored in said third storing means if the value stored in the fourth storing means is less than or equal to the signal stored in said third storing means, and means for disconnecting said heating means only after a predetermined number of successive digital signals stored in said fourth means have a value less than or equal to the digital signal stored in said third storing means and have thus denoted a stabilized weight loss condition.
2. A digital moisture meter comprising balance means including a platen for receiving a sample therein and means for producing digital signals having values in accordance with the weight of the sample on said platen, means above said platen for heating said sample, first and second registers, means for forwarding a first digital signal having a value representative of the initial weight of said sample to said first register for storage therein and for subsequently forwarding successive digital signals having values representative of later weights of said sample to said register for storage therein, calculating means for receiving the digital signals stored in said first and second registers to provide successive digital signals each of which has a value representative of the percent weight loss of said sample for each of said successive digital signals, third and fourth registers, said fourth register storing said digital signals having values representative of the percent weight loss, and comparing means connected to said third and fourth registers for transferring the latest digital signal stored in said fourth register to said third register when the value of the latest digital signal stored in said fourth register is greater than the digital signal stored in said third register and in which the digital signal stored in said third register is retained in said third register when said digital signal in said fourth register is less than or equal to the digital signal stored in said third register, means for counting the number of times the latest digital signal stored in said fourth register is less than or equal to the digital signal stored in said third register, and means responsive to said last-mentioned means for disabling said heating means after said last-mentioned means has reached a predetermined count and has thus denoted a stabilized weight loss condition.
3. A method of determining the percent moisture loss in a relatively small sample comprising the steps of obtaining a first digital signal having a value representative of the initial weight of said sample, storing said first digital signal, subjecting said sample to a source of heat, obtaining a second digital signal having a value representative of the weight of said sample at a later time, storing said second digital signal, calculating from said first and second digital signals a third digital signal having a value representative of the percent weight loss, storing said third digital signal, obtaining a fourth digital signal having a value representative of the weight of said sample at a still later time, storing said fourth digital signal, calculating from said first and fourth digital signals a fifth digital signal having a value representative of the percent weight loss occurring at said still later time, comparing said third and fifth digital signals to ascertain whether the fifth digital signal has a value greater than that of said third digital signal, or less than or equal to the value of said third digital signal, continuing to subject said sample to said heat source if the value of said fifth digital signal is greater than the value of said third digital signal, and removing said heat source when the value of said fifth digital signal is equal to a predetermined value.
4. A method in accordance with claim 3 including the steps of obtaining additional third and fifth digital signals and determining when a predetermined number of fifth digital signals are less than or equal to a third digital signal, said predetermined number of fifth digital signals when less than or equal to a third digital signal denoting a stabilized weight loss condition.