# US 10,865,520 B2 · Method and apparatus for controlling a fiber fractionation system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,520 B2 - Document ID: US10865520B2 - Status: Granted - Kind: B2 - Application number: 16/133,995 - Filed: 2018-09-18 - Published: 2019-03-21 - Granted: 2020-12-15 - Earliest claimed: 2017-09-18 - Assignees: International Paper Company - Applicants: International Paper Company - Inventors: Jyrki Tapio Jaakkola; Antti Heikkinen - Web page: https://patentgrep.com/patent/US10865520B2 ## CPC - D21D 5/06: Rotary screen-drums - B03B 5/56: Drum classifiers - B03B 13/00: Control arrangements specially adapted for wet-separating apparatus or for dressing plant, using physical effects - D21D 99/00: Subject matter not provided for in other groups of this subclass - D21G 9/0018: {controlling the stock preparation} - D21D: TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE - B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS - D21G: CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H) ## Abstract A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers includes measuring an average LF fiber length at one or more locations post-fractionation, and maintaining the average LF fiber length within a target variability range by automatically altering a rotational speed of a rotor of the fiber fractionation system. ## Claims ### Claim 1 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, the method comprising: measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by automatically altering a rotational speed of a rotor of the fiber fractionation system, wherein: the fiber fractionation system comprises an initial mass reject ratio (RRm); and maintaining the average LF fiber length within the target variability range further comprises automatically altering the initial RRm to a second RRm. ### Claim 2 (depends on 1) The method of claim 1, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 3 (depends on 1) The method of claim 1, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 4 (depends on 1) The method of claim 1, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 5 (depends on 1) The method of claim 1, further comprising: altering at least one parameter of at least one post-fractionation processing step to maintain the average LF fiber length within the target variability range. ### Claim 6 (depends on 1) The method of claim 1, further comprising: measuring one or more properties of a furnish formed by mixing the LF stream and the SF stream; and automatically altering the rotational speed of the rotor of the fiber fractionation system to maintain at least one of the one or more measured furnish properties within a respective target range. ### Claim 7 (depends on 6) The method of claim 6, wherein the one or more measured furnish properties comprise the average LF fiber length, an average SF fiber length, a measured furnish strength, or a predicted furnish strength. ### Claim 8 (depends on 1) The method of claim 1, further comprising: measuring one or more properties of a moving web; and automatically altering the rotational speed of the rotor of the fiber fractionation system to maintain at least one of the one or more measured moving web properties within a respective target range. ### Claim 9 (depends on 8) The method of claim 8, wherein the one or more measured moving web properties comprise a porosity or a predicted strength property of a finished sheet, the predicted strength property comprising one or more of a short-span compressive strength, a burst strength, or a crush resistance. ### Claim 10 (depends on 1) The method of claim 1, further comprising: measuring one or more properties of a finished sheet; and automatically altering the rotational speed of the rotor of the fiber fractionation system to maintain at least one of the one or more measured finished sheet properties within a respective target range. ### Claim 11 (depends on 10) The method of claim 10, wherein the one or more measured finished sheet properties comprise a basis weight, a porosity, or a strength property, the strength property comprising one or more of a short-span compressive strength, a burst strength, or a crush resistance. ### Claim 12 (depends on 1) The method of claim 1, further comprising: transmitting a signal to a bale selector to alter a composition of raw material bales selected for an input material. ### Claim 13 (depends on 12) The method of claim 12, wherein the signal is transmitted to the bale selector in response to one of the measured average LF fiber length or a level of stock in a LF fiber storage tank. ### Claim 14 (depends on 1) The method of claim 1, further comprising: prior to fractionation, processing a pulp suspension comprising the LF and SF fibers with a turbulence generator. ### Claim 15 (depends on 1) The method of claim 1, further comprising: treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to alter an amount of free fines present in the LF and SF streams. ### Claim 16 (depends on 1) The method of claim 1, further comprising: during fractionation, applying water to one or more portions of an interior surface of a fractionation screen of the fiber fractionation system. ### Claim 17 (depends on 1) The method of claim 1, wherein measuring the average LF fiber length is performed in real-time. ### Claim 18 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, wherein the fiber fractionation system comprises an initial mass reject ratio (RRm), the method comprising: measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by automatically altering: (i) a rotational speed of a rotor of the fiber fractionation system; and (ii) the initial RRm to a second RRm. ### Claim 19 (depends on 18) The method of claim 18, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 20 (depends on 18) The method of claim 18, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 21 (depends on 18) The method of claim 18, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 22 (depends on 18) The method of claim 18, wherein measuring the average LF fiber length is performed in real-time. ### Claim 23 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, wherein the fiber fractionation system comprises an initial mass reject ratio (RRm), the method comprising: prior to fractionation, processing a pulp suspension comprising the LF and SF fibers with a turbulence generator; measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by automatically altering at least one of: (i) a rotational speed of a rotor of the fiber fractionation system; or (ii) the initial RRm to a second RRm. ### Claim 24 (depends on 23) The method of claim 23, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 25 (depends on 23) The method of claim 23, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 26 (depends on 23) The method of claim 23, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 27 (depends on 23) The method of claim 23, wherein measuring the average LF fiber length is performed in real-time. ### Claim 28 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, the method comprising: measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to enhance binding of fines to the LF fibers, wherein the one or more chemicals are added prior to fractionation, during fractionation, or both, wherein the fiber fractionation system comprises an initial mass reject ratio (RRm) and wherein maintaining the average LF fiber length within the target variability range further comprises one or more of: automatically altering at least one of: (i) a rotational speed of a rotor of the fiber fractionation system; or (ii) the initial RRm to a second RRm; or applying, during fractionation, water to one or more portions of an interior surface of a fractionation screen of the fiber fractionation system. ### Claim 29 (depends on 28) The method of claim 28, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 30 (depends on 28) The method of claim 28, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 31 (depends on 28) The method of claim 28, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 32 (depends on 28) The method of claim 28, wherein measuring the average LF fiber length is performed in real-time. ### Claim 33 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, the method comprising: measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to reduce binding of fines to the LF fibers, wherein the one or more chemicals are added prior to fractionation, during fractionation, or both, wherein the fiber fractionation system comprises an initial mass reject ratio (RRm) and wherein maintaining the average LF fiber length within the target variability range further comprises one or more of: automatically altering at least one of: (i) a rotational speed of a rotor of the fiber fractionation system; or (ii) the initial RRm to a second RRm; or applying, during fractionation, water to one or more portions of an interior surface of a fractionation screen of the fiber fractionation system. ### Claim 34 (depends on 33) The method of claim 33, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 35 (depends on 33) The method of claim 33, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 36 (depends on 33) The method of claim 33, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 37 (depends on 33) The method of claim 33, wherein measuring the average LF fiber length is performed in real-time. ### Claim 38 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, the method comprising: measuring an average LF fiber length at one or more locations post-fractionation; and maintaining the average LF fiber length within a target variability range by applying, during fractionation, water to one or more portions of an interior surface of a fractionation screen of the fiber fractionation system, wherein the fiber fractionation system comprises an initial mass reject ratio (RRm) and wherein maintaining the average LF fiber length within the target variability range further comprises one or more of: automatically altering at least one of: (i) a rotational speed of a rotor of the fiber fractionation system; or (ii) the initial RRm to a second RRm; treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to enhance binding of fines to the LF fibers; or treating the pulp suspension comprising the LF and SF fibers with one or more chemicals to reduce binding of fines to the LF fibers, wherein the one or more chemicals are added prior to fractionation, during fractionation, or both. ### Claim 39 (depends on 38) The method of claim 38, wherein the rotational speed of the rotor is controlled by a frequency converter. ### Claim 40 (depends on 38) The method of claim 38, wherein measuring the average LF fiber length is performed immediately after fractionation. ### Claim 41 (depends on 38) The method of claim 38, wherein measuring the average LF fiber length is performed after one or more post-fractionation processing steps. ### Claim 42 (depends on 38) The method of claim 38, wherein measuring the average LF fiber length is performed in real-time. ### Claim 43 (depends on 38) The method of claim 38, wherein applying water to one or more portions of the interior surface of a fractionation screen comprises spraying, via a forming shower, adjustable pressure water. ### Claim 44 A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers, the method comprising: measuring an average SF fiber length at one or more locations post-fractionation; and maintaining the average SF fiber length within a target variability range by automatically altering a rotational speed of a rotor of the fiber fractionation system, wherein: the fiber fractionation system comprises an initial mass reject ratio (RRm); and maintaining the average SF fiber length within the target variability range further comprises automatically altering the initial RRm to a second RRm. ### Claim 45 (depends on 44) The method of claim 44, wherein maintaining the average SF fiber length within the target variability range further comprises treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to enhance binding of fines to the LF fibers, wherein the one or more chemicals are added prior to fractionation, during fractionation, or both. ### Claim 46 (depends on 44) The method of claim 44, wherein maintaining the average SF fiber length within the target variability range further comprises treating a pulp suspension comprising the LF and SF fibers with one or more chemicals to reduce binding of fines to the LF fibers, wherein the one or more chemicals are added prior to fractionation, during fractionation, or both. ### Claim 47 (depends on 44) The method of claim 44, wherein maintaining the average SF fiber length within the target variability range further comprises applying, during fractionation, water to one or more portions of an interior surface of a fractionation screen of the fiber fractionation system.