Patents Assigned to Pulp & Paper Research Institute of Canada
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Patent number: 7074845Abstract: A novel filler treatment comprising the preparation of swollen starch-latex compositions, prepared in the presence or absence of co-additives, and the addition of the said composition to a filler suspension, has been developed. Use of the treated filler during papermaking improves filler retention and produces filled papers where addition of the filler has only a minimal negative effect on strength properties. The swollen starch-latex compositions can be prepared in a batch or jet cooker, or by mixing with hot water under controlled conditions (i.e., temperature, pH, mixing, mixing time) in order to make the starch granules swell sufficiently to improve their properties as a filler additive but avoiding excess swelling leading to their rupture. The swollen starch-latex composition is then rapidly mixed with the filler slurry, preferably in a static mixer, and added to the papermaking furnish at a point prior to the headbox of the paper machine.Type: GrantFiled: April 7, 2003Date of Patent: July 11, 2006Assignee: Pulp and Paper Research Institute of CanadaInventor: Makhlouf Laleg
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Patent number: 7010376Abstract: A method and apparatus to perform an automatic diagnosis for the poor performance of a control loop, and to determine whether or not the malfunctioning is caused principally by a poor adjustment of the controller tuning parameters. The method makes use of the fact that a poorly tuned control loop amplifies disturbances in a narrow frequency range around the so-called resonant frequency. The method comprises measuring an error in a control loop over time to determine a power spectral density of the error, determining a best fit analytical function describing the power spectral density and measuring a diagnostic value from a difference between the best fit analytical function and the power spectral density of the error.Type: GrantFiled: October 24, 2003Date of Patent: March 7, 2006Assignee: Pulp and Paper Research Institute of CanadaInventors: Lahoucine Ettaleb, Alain André Roche
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Patent number: 6998015Abstract: A method is disclosed for reducing or inhibiting alkaline darkening of mechanical pulp caused by the presence of calcium carbonate filler during production; the method comprises adding a sulfite, or sulfur-containing reducing agent, especially a sulfite to the mechanical pulp and the filler; the method is usefully applied in the production of mechanical pulp and paper in which calcium carbonate is used as a filler and also in the production of paper at neutral or mildly alkaline conditions.Type: GrantFiled: November 27, 2001Date of Patent: February 14, 2006Assignee: Pulp and Paper Research Institute of CanadaInventors: Xujun Hua, Makhlouf Laleg
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Publication number: 20050269049Abstract: A novel method for the production of light-stable and process-stable lignocellulosic materials, in particular, the production of mechanical wood pulps with much improved light and process stability is described, as well as the resulting pulps of improved light and process stability and papers containing such pulps. The novel method involves the reaction of lignocellulosic materials such as bleached chemithermomechanical pulps (BCTMP) with (a) a water-soluble, fibre-reactive yellowing inhibitor possessing two or more secondary amino or ammonium (—NHR? or —HN+HR?), tertiary amino or ammonium (—NR?R? or —HN+R?R?), and/or quaternary ammonium (—N+R?R?R??) functional groups in an aqueous medium, or (b) a water-soluble, fibre-reactive hindered amine light stabilizer possessing said amino or ammonium functional groups in an alkaline peroxide bleaching medium or in an aqueous medium with a subsequent bleaching of the materials in an alkaline peroxide bleaching medium.Type: ApplicationFiled: October 21, 2003Publication date: December 8, 2005Applicant: Pulp and Paper Research Institute of CanadaInventors: Thomas Hu, Ivan Pilulik, Trevor Williams
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Patent number: 6840470Abstract: This invention relates to a refiner force sensor for refiners used in the pulp and paper industry, to a refining apparatus, and to a method of measuring force acting on a refiner bar in a refiner.Type: GrantFiled: March 14, 2001Date of Patent: January 11, 2005Assignees: Pulp and Paper Research Institute of Canada, Queen's University at Kingston, University of British ColumbiaInventors: Alan Henry Bankes, Peter Martin Wild, Daniel Ouellet, Behrouz Shiari, Seyed Mohammad Ali Siadat, John Jaa Senger
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Patent number: 6806955Abstract: The invention relates to a fluorescence microscopy technique for measuring physical and chemical properties of individual fiber-like particles. Fluorescence intensity per unit length is shown to be proportional to the fiber coarseness. In addition, other fiber properties such as fiber length, width and wall thickness can be obtained from fluorescence images, and lignin content from fluorescence spectra. The present invention will provide a process for determining the uniformity of pulp samples in terms of the physical and chemical properties of the individual fiber-like particles, particularly wood pulp fibers.Type: GrantFiled: December 17, 2001Date of Patent: October 19, 2004Assignee: Pulp and Paper Research Institute of CanadaInventor: Ho Fan Jang
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Patent number: 6670524Abstract: The present invention relates to a novel method for the prediction of fiber length and the selection of superior trees using genetic marker loci. The method comprises comparing genotypic survey data to phenotypic data collected from the same trees used to create the genotypic survey and identifying particular genetic marker loci or quantitative trait loci (QTL's) that are associated with fiber length. The method allows superior trees to be identified, from both plantations and natural populations, and selected for in tree improvement breeding programs by genotyping with identified genetic marker loci.Type: GrantFiled: January 31, 2000Date of Patent: December 30, 2003Assignee: Pulp and Paper Research Institute of CanadaInventors: Simon Potter, Paul A. Watson
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Patent number: 6660128Abstract: A method for selectively delignifying lignocellulosic materials and bleaching of pulp and dyes using a combination of an oxidative enzyme and a metal complex. More specifically, the process involves the oxidation of a transition metal redox complex by a phenol oxidizing enzyme such as laccase or peroxidase to mediate the catalytic delignification of chemical pulp and bleaching of textile dye. This process is unique in that only a catalytic amount of metal complex mediator is required on softwood or hardwood kraft pulp, and that recycling or regeneration of the mediator for further pulp delignification is possible. The redox mediator is characterized in that it contains a transition metal ion coordinated with molecules or ions in such a way that the complexes have a formal redox potential between 0.5 and 1.2 volt measured against a normal hydrogen electrode.Type: GrantFiled: October 10, 2000Date of Patent: December 9, 2003Assignees: Pulp and Paper Research Institute of Canada, Universié de MontréalInventors: Robert Bourbonnais, Dominic Rochefort, Michael G. Paice, Sylvie Renaud, Dónal Leech
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Patent number: 6551451Abstract: A rapid method is provided for the on-line spectroscopic determination of lignin content and/or kappa number in wood pulps. Unlike currently available commercial instrumentation, the method enables one to measure lignin content independently of species variations and pulp consistency.Type: GrantFiled: December 20, 2000Date of Patent: April 22, 2003Assignee: Pulp and Paper Research Institute of CanadaInventors: Thanh P. Trung, Denys Leclerc
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Patent number: 6468396Abstract: A papermaking stock and a method for improving the retention of pulp fines, mineral fillers, dispersed wood resin, and/or synthetic hydrophobic stickies and cellulose fibers in a cellulosic fiber sheet, employs dendrimeric polymers for increasing the retention of fines, fillers, dispersed hydrophobic particles, and cellulosic fibers. The application in the paper industry provides a means of (1) increasing the retention of fillers in paper and decreasing the loss of filler materials in white water waste from papermaking; (2) increasing the retention of cellulosic fines and fibers in the paper-making process; increasing drainage on the paper machine; and (3) removing a significant fraction of the wood resin, plastics, and stickies from the process stream thus enabling a greater extent of reuse of filtrates and, hence, less effluents from mills, fewer problems from wood resins such as deposit formation, loss of strength of product, and contamination of product with dirt particles.Type: GrantFiled: April 4, 2001Date of Patent: October 22, 2002Assignee: Pulp and Paper Research Institute of CanadaInventors: Lawrence Harvey Allen, Marco Savio Polverari
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Patent number: 6455661Abstract: A graft polymer comprises a carbohydrate polymer having pendant 3-amino-2-hydroxy propyl groups grafted thereon and may be employed as a retention aid and strengthening additive in paper manufacture. When the carbohydrate polymer is a component of wood pulp the resulting chemically modified wood pulp may be employed in conjunction with unmodified wood pulp to incorporate therein the retention and strengthening characteristics.Type: GrantFiled: July 2, 2001Date of Patent: September 24, 2002Assignee: Pulp and Paper Research Institute of CanadaInventors: Miroslav Antal, Makhlouf Laleg, Ivan Ignac Pikulik
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Patent number: 6339222Abstract: A method for determining the concentration of hydrogen ion, organic anionic species and anionic species selected from the group consisting of OH−, CO3═, HS−, ClO3−, SO4═, S2O3═, polysulphide and peroxide in an aqueous sample solution, said method comprising subjecting said solution to near infrared radiation at a wavelength region of wave numbers selected from about 7,000 to 14,000 cm−1 through a solution path length of at least 3 mm to obtain spectral data for said solution; obtaining comparative spectral data for said anionic species at known concentrations in aqueous solutions; and correlating by multivariate calibration the relationships between said spectral data of said sample solution and said comparative spectral data to determine said concentration of said anionic species in said sample solution.Type: GrantFiled: May 19, 1999Date of Patent: January 15, 2002Assignees: Kvaerner Canada Inc., Pulp & Paper Research Institute of CanadaInventors: Michael Kester, Denys F. Leclerc, Thanh P. Trung, Edward A. Dylke
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Patent number: 6336602Abstract: In the mechanical refining of wood chips to produce wood pulp, wood pulp quality is improved by employing low refining intensity at least in a final refining stage; the refining is carried out in a double disc refiner or a single disc refiner at rotational speeds that are lower than those conventionally employed, specifically at less than 1200 RPM in a double disc refiner and at less than 1500 RPM in a single disc refiner.Type: GrantFiled: May 24, 1999Date of Patent: January 8, 2002Assignee: Pulp and Paper Research Institute of CanadaInventor: Keith Miles
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Patent number: 6279495Abstract: A method and an apparatus for optimizing the combustion air system in a power boiler or chemical recovery boiler by improving fluid flow and gas mixing are disclosed, whereby one can increase boiler capacity and combustion uniformity and reduce particulate and gaseous emissions. The method involves interlacing of the secondary and, where applicable, the tertiary air supply through opposing air ports on all four walls of the boiler, and is implemented by alternately opening wide or partially closing a port damper on one side, while partially closing or opening wide a port damper on the opposite side, such that a 70-100% open damper on one side opposes a partially closed (10-40% open) damper on the other and vice versa in an alternating fashion, along opposing walls.Type: GrantFiled: July 3, 2000Date of Patent: August 28, 2001Assignee: Pulp and Paper Research Institute of CanadaInventors: Ibrahim Karidio, Victor Uloth, Klaus Weiss
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Patent number: 6235154Abstract: A method which enhances the effectiveness of chlorine dioxide bleaching of lignocellulosic materials. It is effected by adding to the chlorine dioxide bleaching stage an aldehyde compound at a concentration of from about 0.01% to about 20%, by weight of the oven-dried lignocellulosic material.Type: GrantFiled: March 12, 1999Date of Patent: May 22, 2001Assignee: Pulp and Paper Research Institute of CanadaInventors: Zhi-Hua Jiang, Barbara van Lierop, Richard McK. Berry
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Patent number: 6235150Abstract: A method is described for attaining high levels of loading of calcium carbonate fillers in the lumens of wood pulp fibers. The pulp is pretreated with a cationic polymer prior to being impregnated with the filler. Different conditions of pH and temperature are specified depending on whether the filler is a precipitated calcium carbonate or a ground calcium carbonate. The lumen-loaded pulps are used to make novel products with advantages in higher filler retention and sheet strength over conventionally made papers.Type: GrantFiled: March 18, 1999Date of Patent: May 22, 2001Assignee: Pulp and Paper Research Institute of CanadaInventors: Steven R. Middleton, Josée Desmeules, Anthony M. Scallan
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Patent number: 6153052Abstract: An improved pulping process by which pulp yield is increased requires using polysulfide in the cooking liquor and lignocellulosic particles having a maximum thickness of 2 mm.Type: GrantFiled: September 16, 1999Date of Patent: November 28, 2000Assignee: Pulp and Paper Research Institute of CanadaInventors: Corinne Elizabeth Luthe, Richard McKinnon Berry, Jian Li
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Patent number: 5976375Abstract: A process for reducing the production of biomass during activated sludge treatment of pulp and paper mill effluents, involving a conditioning of the recycled activated sludge (RAS) prior to its return into the aeration tank is described. The conditioning is typically performed within the sludge return line and involves RAS exposure to a waste acidic effluent originating from bleach plants of kraft, sulphite mills or other mill sources.Type: GrantFiled: March 31, 1999Date of Patent: November 2, 1999Assignee: Pulp and Paper Research Institute of CanadaInventors: Joseph G. Dorica, Allan R. Elliott
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Patent number: 5968326Abstract: A composite membrane is disclosed fabricated by depositing an inorganic ion-conducting thin film on a cation-selective organic polymer membrane substrate using Pulse Laser Deposition (PLD) or reactive magnetron sputtering. The fabricated membrane combines the advantages of the polymeric membrane including flexibility and low electrical resistance, with the advantages of the inorganic membrane film including resistance to fouling, high selectivity for alkali metal ions over hydrogen ions and resistance to oxidizing chemicals; electromembrane systems and processes for example alkali metal sensing electrodes and other membrane-based electrochemical detectors, electrolytic and electrodialytic systems incorporate such membranes thus improving their performance in terms of current efficiency, salt to acid conversion ratio, reliable operation and membrane life.Type: GrantFiled: April 8, 1998Date of Patent: October 19, 1999Assignees: Pulp and Paper Research Institute of Canada, Ecole PolytechniqueInventors: Arthur Yelon, Michael Paleologou, Dentcho Ivanov, Ricardo Izquierdo, Michel Meunier
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Patent number: 5942084Abstract: A process using an amphoteric ion-exchange resin, also known as a "snake-cage polyelectrolyte" resin separates kraft white liquor into sulphide-rich and caustic-rich components. The sulphide-rich component can be used in the initial stage of pulping, pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.Type: GrantFiled: January 24, 1997Date of Patent: August 24, 1999Assignees: Pulp and Paper Research Institute of Canada, Eco-Tec LimitedInventors: Rokhsareh Thompson, Michael Paleologou, Richard McKinnon Berry, Craig J. Brown, Michael Sheedy