# US 12,000,788 B1 · Inline detection of gypsum panel calcination > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,788 B1 - Document ID: US12000788B1 - Status: Granted - Kind: B1 - Application number: 17/145,519 - Filed: 2021-01-11 - Granted: 2024-06-04 - Earliest claimed: 2020-01-10 - Assignees: Gold Bond Building Products, LLC; Malcam Ltd. - Applicants: Gold Bond Building Products, LLC; MALCAM Ltd. - Inventors: Eli Stav; Danny Moshe - Web page: https://patentgrep.com/patent/US12000788B1 ## CPC - G01N 22/04: Investigating moisture content - C01F 11/46: Sulfates (dehydration of gypsum {for the production of calcium sulfate cements} C04B11/02) - C04B 11/00: Calcium sulfate cements - G01N 33/38: Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass - C01P 2006/82: water content - C04B 2111/0062: {Gypsum-paper board like materials} - 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) - C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00}) - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract The present invention is directed to a method of determining a free moisture content and/or a degree of calcination of a gypsum panel. The method comprises the following: (a) transmitting a microwave beam through at least a first portion of the gypsum panel, such that said microwave beam is a transmitted microwave beam; (b) receiving the transmitted microwave beam to form a received microwave beam; (c) determining a phase shift and an attenuation from the received microwave beam; (d) repeating steps (a) to (c) for at least a second portion of the gypsum panel, such that a plurality of phase shifts and a plurality of attenuations is obtained; (e) using at least one empirical factor to correct the plurality of attenuations, producing a plurality of corrected attenuations; (f) calculating a raw moisture content of the gypsum panel from the corrected attenuations wherein the raw moisture content comprises a raw free moisture content and a raw crystal moisture content; (g) using a calibration factor to correct the plurality of phase shifts, producing a plurality of corrected phase shifts; (h) determining a density of the gypsum panel from the corrected phase shifts; and (i) calculating a final moisture content of the gypsum panel from the density and from the raw moisture content wherein the final moisture content comprises a final free moisture content and a final crystal moisture content. ## Claims ### Claim 1 A method of determining a free moisture content and/or a degree of calcination of a gypsum panel comprising a gypsum core, a first sheet of facing material, and a second sheet of facing material wherein the first sheet of facing material and the second sheet of facing material sandwich the gypsum core, the method comprising: (a) transmitting a microwave beam through at least a first portion of the gypsum panel, such that the microwave beam is a transmitted microwave beam; (b) receiving the transmitted microwave beam to form a received microwave beam; (c) determining a phase shift and an attenuation from the received microwave beam; (d) repeating steps (a) to (c) for at least a second portion of the gypsum panel, such that a plurality of phase shifts and a plurality of attenuations is obtained; (e) using at least one empirical factor to correct the plurality of attenuations, producing a plurality of corrected attenuations; (f) calculating a raw moisture content of the gypsum panel from the corrected attenuations wherein the raw moisture content comprises a raw free moisture content and a raw crystal moisture content; (g) using a calibration factor to correct the plurality of phase shifts, producing a plurality of corrected phase shifts; and (i) calculating a final moisture content of the gypsum panel wherein the final moisture content comprises a final free moisture content and a final crystal moisture content. ### Claim 2 (depends on 1) The method according to claim 1, wherein the method is conducted inline during the process of making the gypsum panel. ### Claim 3 (depends on 2) The method according to claim 2, wherein the method is conducted after drying the gypsum panel and before packaging the gypsum panel. ### Claim 4 (depends on 1) The method according to claim 1, wherein the method is conducted offline from the process of making the gypsum panel. ### Claim 5 (depends on 1) The method according to claim 1, wherein the moisture content is within 25% of the actual moisture content. ### Claim 6 (depends on 1) The method according to claim 1, wherein the microwave beam includes only one frequency. ### Claim 7 (depends on 1) The method according to claim 1, wherein the microwave beam includes at least two frequencies. ### Claim 8 (depends on 1) The method according to claim 1, wherein the microwave beam includes one or more frequencies within a range of from 10 GHz to 75 GHz. ### Claim 9 (depends on 1) The method according to claim 1, wherein the gypsum panel features an irregularity in a density calculated by comparing one of the plurality of corrected phase shifts to a previous value of the corrected phase shifts, such that the irregularity is detected if one of the plurality of corrected phase shifts differs from the previous value. ### Claim 10 (depends on 1) The method according to claim 1, wherein the corrected attenuations and the corrected phase shifts are further corrected by removing attenuations and phase shifts produced after the microwave beam passes through an edge of the gypsum panel, such that a first portion of the microwave beam passes through the portion of the gypsum panel and a second portion of the microwave beam substantially does not pass through the portion of the gypsum panel. ### Claim 11 (depends on 1) The method according to claim 1, the method further comprising determining a density of the gypsum panel, wherein the step of determining the density includes detecting a defect in the gypsum panel. ### Claim 12 (depends on 6) The method according to claim 6, wherein the defect includes the presence of a foreign body inside the gypsum panel. ### Claim 13 (depends on 1) The method according to claim 1, wherein the at least one empirical factor is a plurality of empirical factors comprising the weight of the gypsum panel, the type of the gypsum panel, or a combination thereof. ### Claim 14 (depends on 1) The method according to claim 1, wherein the plurality of corrected attenuations is further corrected by removing attenuations produced after the microwave beam passes through at least a portion of the gypsum panel. ### Claim 15 (depends on 1) The method according to claim 1, wherein the gypsum panel comprises calcium sulfate dihydrate. ### Claim 16 (depends on 1) The method according to claim 1, wherein the method further comprises a step of undertaking remedial action after determining the moisture content.