Patents Assigned to Pulp and Paper Research Institute of Canada
  • Patent number: 4510020
    Abstract: Paper of improved properties is produced from pulp in which filler is selectively loaded within the fiber lumens by agitating a suspension of pulp and filler until the fiber lumens become loaded with filler, separating the residual suspended filler from the loaded fibers and vigorously washing the pulp until substantially all of the filler on the external surfaces of the fibers is removed.
    Type: Grant
    Filed: June 12, 1980
    Date of Patent: April 9, 1985
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Harold V. Green, Thomas J. Fox, Anthony M. Scallan
  • Patent number: 4431479
    Abstract: A method is provided for treating pulp fibres, that have already been curled which method comprises: subjecting the pulp to a heat treatment while the pulp is at a high consistency, thereby to render the curl permanent to subsequent mechanical action. This permanent curl has advantages for papermachine runnability and for increasing the toughness of the finished product.
    Type: Grant
    Filed: May 11, 1982
    Date of Patent: February 14, 1984
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Michel Barbe, Rajinder S. Seth, Derek H. Page
  • Patent number: 4391671
    Abstract: Biomass residue is added at the cold end of a rotary calcination kiln to generate heat in situ thereby diminishing substantially the amount of fossil fuel normally fired at the hot end of the kiln.
    Type: Grant
    Filed: May 27, 1981
    Date of Patent: July 5, 1983
    Assignee: Pulp and Paper Research Institute of Canada
    Inventor: Mahmoud K. Azarniouch
  • Patent number: 4313790
    Abstract: A process is disclosed for the production of paper and paper-like products which consists of the addition to the papermaking furnish of kraft lignin or modified kraft lignin and poly(oxyethylene).
    Type: Grant
    Filed: March 31, 1980
    Date of Patent: February 2, 1982
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Robert H. Pelton, Lawrence H. Allen, Henry M. Nugent
  • Patent number: 4285787
    Abstract: A method is provided herein for the electrochemical corrosion protection of a partly submersed, rotating, stainless steel drum in a vat containing a corrosive, oxidizing, chloride-containing bleach liquor. The method comprises the step of impressing a protection potential to the stainless steel drum at a predetermined voltage in the range of -600 to +400 mV.sub.Ag/AgCl. This predetermined voltage is sufficiently low to draw the stainless steel into a passive corrosion protection zone. However, that voltage is not sufficiently low to draw the stainless steel into a zone of uniform corrosion. Specific means for the placement of the anode in the vat are also provided.
    Type: Grant
    Filed: March 20, 1980
    Date of Patent: August 25, 1981
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Andrew Garner, Laurent H. Laliberte
  • Patent number: 4285232
    Abstract: A monitor assembly for monitoring the effectiveness of a method and apparatus for electrochemical crevice corrosion protection by electrochemical potential control of a stainless steel vessel containing a corrosive washing solution, e.g. bleach plant washer equipment used in the pulp industry.
    Type: Grant
    Filed: March 20, 1980
    Date of Patent: August 25, 1981
    Assignee: Pulp and Paper Research Institute of Canada
    Inventor: Andrew Garner
  • Patent number: 4266918
    Abstract: Method and apparatus are provided for producing a filament from molten rapidly crystallizing fibre-forming thermoplastic polymers. The apparatus includes a chamber for such molten crystallizable polymer having an electrically conductive orifice at one end of such chamber. Means are provided for applying sufficient pressure to the column of molten crystallizable polymer to form a flat meniscus at the orifice. An apertured plate of electrically conductive material (e.g. steel) is disposed a predetermined distance from the orifice. Finally, means are provided for applying a high voltage D.C. between the orifice and the apertured plate creating an electrostatic field which exerts a force on the column of the fluid (molten) polymer. Above a certain critical field strength the flat meniscus at the orifice is deformed into a conical shape from which a fine continuous jet of molten polymer is drawn.
    Type: Grant
    Filed: September 6, 1978
    Date of Patent: May 12, 1981
    Assignee: Pulp and Paper Research Institute of Canada
    Inventor: Rockliffe S. Manley
  • Patent number: 4248663
    Abstract: Lignocellulosic materials such as wood, bagasse, straw, reeds, and other plants and crops can be delignified effectively by a soda-type pulping with an alkaline liquor containing small quantities of both ethylenediamine or like amino compound, and a cyclic keto compound, such as anthraquinone. Pulping rates comparable to kraft are achieved and the pulps thereby obtained have excellent physical properties, especially tear strength.
    Type: Grant
    Filed: July 5, 1978
    Date of Patent: February 3, 1981
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: George J. Kubes, James M. MacLeod, Bruce I. Fleming, Henry I. Bolker
  • Patent number: 4233600
    Abstract: A refiner plate clash detection system and method for plate clash detection is provided herein. The system includes a receiver for a first signal having a significant increase in level at at least one distinct predetermined frequency related to the clash and the characteristics of the discs of the refiner. A filter is provided having a passband matched to pass the distinct frequency of the signal to provide a filtered output signal in which the center frequency of the passband of the filter is determined by the formulaf.sub.o =n.SIGMA..sub.Rwhereinf.sub.o is the center frequency (expressed in Hertz) of said passbandn=the number of segments at a given radius, per single disc and.SIGMA..sub.R =the sum of the rotational rates (expressed in Hertz) of the two discs enclosing a given refining volume.The filtered signal is then smoothed. A threshold level is established.
    Type: Grant
    Filed: June 7, 1978
    Date of Patent: November 11, 1980
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: James H. Rogers, Donald J. Butler
  • Patent number: 4025472
    Abstract: An economic process is provided for effectively drying wet, highly swollen, polymer-modified, cellulosic fibres to provide fibres having enhanced properties of both water and physiological liquid retention. The essential steps of the drying process are as follows: First, the hydrolyzed fibres are thoroughly washed with water, thus rendering them to a substantially maximum swollen state. The fibres are then acidified to a low, critical pH whereby the water previously retained by the alkaline fibre is released and filtered off, thus rendering them to a substantially minimum swollen state. The product may be subjected to an optional non-shearing stirring step while in a low consistency dispersion prior to the acidification step. Further treatment with an alkali non-swelling solvent mixture renders the fibres substantially water-free in their alkaline salt form.
    Type: Grant
    Filed: June 24, 1975
    Date of Patent: May 24, 1977
    Assignee: Pulp and Paper Research Institute of Canada
    Inventor: Pierre Lepoutre
  • Patent number: 4008161
    Abstract: A multi-step method is provided for the purification of waste water, especially pulp mill effluents. It comprises a number of steps carried out in a specific sequence. The first step involves passing an oxygen-containing gas through the waste water while the waste water is in intimate contact with a finely divided activated carbonaceous material, preferably including, as a preliminary step, the addition of the finely divided activated carbonaceous material to the waste water. The second step involves adding a clarification agent selected from one or more of a coagulant, a flocculant, and a polyelectrolyte to the treated waste water provided by the first step. The third step involves recovering a solids-free effluent by known means, e.g.
    Type: Grant
    Filed: November 29, 1974
    Date of Patent: February 15, 1977
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Alfred Wong, Steven Prahacs, Joseph Dorica
  • Patent number: 3981453
    Abstract: A method for segregating bark and/or foliage from wood chips and/or twigs in a mixture of such components is provided. The method includes three essential steps. The first step comprises conditioning a pile of such mixture by periodically sprinkling the pile with water during storage. The second step comprises vigorously agitating the conditioned mixture with sufficient water, and for sufficient time to break bonded bark from the wood chips and the twigs and to comminute the bark. The third step comprises wet screening the agitated mixture thereby separating effluent bark and foliage from the wood chips and/or twigs in the mixture. An additional step includes dewatering the effluent bark and foliage, thereby to recover screened out solids materials. This method can be operated successfully on either a batch or a continuous basis without any serious effect on the reduction of pulp quality.
    Type: Grant
    Filed: November 29, 1974
    Date of Patent: September 21, 1976
    Assignee: Pulp and Paper Research Institute of Canada
    Inventors: Robin Wilfrid Berlyn, James David Hutchinson