# US 7,609,074 B2 · Electronic moisture tester > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,074 B2 - Document ID: US7609074B2 - Status: Granted - Kind: B2 - Application number: 11/066,850 - Filed: 2005-02-24 - Published: 2006-08-24 - Granted: 2009-10-27 - Earliest claimed: 2005-02-24 - Assignees: Sunsweet Growers, Inc. - Inventors: Brian N. Pierce; Orion Davies; Michael Gildemeister - Web page: https://patentgrep.com/patent/US7609074B2 ## CPC - G01N 33/025: {Fruits or vegetables} - G01N 27/048: {for determining moisture content of the material} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The moisture content of a foodstuff or other solid matter is determined by reducing the matter to a paste, packing the paste into a vessel equipped with multiple pairs of plate electrodes and one or more temperature sensors, applying an AC voltage across each pair of electrodes, and measuring the impedance of the paste from each pair of electrodes. The multiple impedance measurements are averaged or otherwise processed to obtain a value that is representative of the paste, and that value and the temperature are processed against calibration data to achieve a value of the moisture content of the paste. ## Claims ### Claim 1 A process for determining moisture content in solid matter, said process comprising: (a) reducing said solid matter to a paste; (b) placing said paste in an elongated vessel having a longitudinal axis, said vessel containing a plurality of independent pairs of electrodes positioned at a plurality of locations along said axis, the electrodes of any single pair directly opposing each other across said axis; (c) imposing an alternating voltage at a selected frequency across each of said pairs of electrodes and through said paste, determining an electrical impedance value across each of said pairs arising from said alternating voltage, and generating a signal representative of each of said values; (d) detecting the temperature of said paste in said elongated vessel; and (e) compiling test data from said signals and said temperature, and comparing said test data so compiled to calibration values correlating said test data with moisture levels, thereby determining said moisture content of said solid matter. ### Claim 2 (depends on 1) The process of claim 1 wherein the electrodes of any single pair are separated by a gap, and the gaps of all said pairs are of equal width. ### Claim 3 (depends on 1) The process of claim 1 wherein said elongated vessel contains from 5 to 100 pairs of electrodes. ### Claim 4 (depends on 1) The process of claim 1 wherein said elongated vessel contains from 10 to 60 pairs of electrodes. ### Claim 5 (depends on 1) The process of claim 1 wherein said alternating voltage has a maximum voltage ranging from about 1 mV to about 100 V. ### Claim 6 (depends on 1) The process of claim 1 wherein said alternating voltage has a maximum voltage ranging from about 0.1 V to about 50 V. ### Claim 7 (depends on 1) The process of claim 1 wherein said alternating voltage has a maximum voltage ranging from about 0.3 V to about 30 V. ### Claim 8 (depends on 1) The process of claim 1 wherein said selected frequency is from about 60 Hz to about 200 kHz. ### Claim 9 (depends on 1) The process of claim 1 wherein said selected frequency is from about 300 Hz to about 30 kHz. ### Claim 10 (depends on 1) The process of claim 1 wherein step (a) comprises forcing said solid matter through a perforated plate. ### Claim 11 (depends on 1) The process of claim 1 wherein step (b) comprises placing from about 3 to about 3,000 cm3 of said paste in said elongated vessel. ### Claim 12 (depends on 1) The process of claim 1 wherein step (b) comprises placing from about 10 to about 1,000 cm3 of said paste in said elongated vessel. ### Claim 13 (depends on 1) The process of claim 1 wherein step (d) is performed by at least one thermistor within said vessel. ### Claim 14 (depends on 1) The process of claim 1 wherein step (d) is performed by a plurality of thermistors within said vessel. ### Claim 15 (depends on 1) The process of claim 1 wherein step (e) comprises averaging a plurality of said signals to yield an average signal value and comparing said average signal value and said temperature to values represented on a three-dimensional calibration data curve in which moisture level is plotted as a function of both impedance and temperature. ### Claim 16 An apparatus for determining moisture content in a paste, said apparatus comprising: an elongated vessel for receiving said paste, having a longitudinal axis and containing a plurality of independent pairs of electrodes positioned at a plurality of locations along said axis, the electrodes of any single pair directly opposing each other across said axis; means for imposing an alternating voltage at a selected frequency across each of said pairs of electrodes when said vessel is filled with said paste and for detecting electrical impedance across each of said pairs and through said paste and for correlating said electrical impedance with moisture content; and means for detecting the temperature of the interior of said vessel. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein said elongated vessel is of uniform cross section and the electrodes of any single pair are separated by a gap, the gaps of all said pairs being of equal width. ### Claim 18 (depends on 16) The apparatus of claim 16 comprising from 5 to 100 pairs of said electrodes. ### Claim 19 (depends on 16) The apparatus of claim 16 wherein comprising from 10 to 60 pairs of electrode. ### Claim 20 (depends on 16) The apparatus of claim 16 wherein said means for detecting the temperature of the interior of said vessel are comprised of at least one thermistor. ### Claim 21 (depends on 16) The apparatus of claim 16 wherein said means for detecting the temperature of the interior of said vessel are comprised of a plurality of thermistors. ### Claim 22 (depends on 16) The apparatus of claim 16 further comprising means for reducing solid matter to a paste. ### Claim 23 (depends on 22) The apparatus of claim 22 wherein said means for reducing solid matter to a paste is a drive means arranged to force said solid matter through a perforated plate. ### Claim 24 (depends on 16) The apparatus of claim 16 in which said elongated vessel has an internal capacity of from about 3 to about 3,000 cm3. ### Claim 25 (depends on 16) The apparatus of claim 16 in which said elongated vessel has an internal capacity of from about 10 to about 1,000 cm3. ### Claim 26 (depends on 16) The apparatus of claim 16 in which said elongated vessel is an elongated tube.