Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.

Abstract: Methods for prepressing lignocellulose-containing fibrous material are disclosed including forming a lignocellulose-containing fibrous material into a web, initially compressing the web and permitting expansion of the web, recompressing the web in an entry section of a prepress to a density proximating that of the density of the initially pressed web, permitting the recompressed web to undergo controlled expansion in an expansion section of the prepress, injecting steam into the web within either the entry or expansion sections of the prepress, and transferring the expanded web into a finishing press.

Abstract: Refining elements are disclosed for use in refiners in which the refining elements comprise a refining surface with a plurality of raised bars alternating with a plurality of grooves. The raised bars at the inlet of the refining path have a first spacing and form a first angle with respect to a radius or generatrix defining the refining path and the plurality of raised bars at the outlet of the refining path have a second spacing and form a second angle with respect to the radius or generatrix, the first angle being between about 50.degree. and 85.degree. and the second angle being between about -25.degree. and +25.degree., and the first spacing being greater than the second spacing.

Abstract: Pulp-dewatering apparatus is disclosed including a pair of press rolls and a rotatable pulp disintegrating screw above the nip region between the press rolls, and the apparatus includes a pair of doctor bars associated with the pair of press rolls, each doctor bar including a doctor blade for removing pulp from the surface of its associated press roll, and in which one of the doctor blades is disposed adjacent to the nip region below the pulp disintegrating screw such that the space between the pair of press rolls and the pulp disintegrating screw in which a pulp cake can form is substantially reduced.

Abstract: A process for the purification of a fiber suspension (deinking or white water) in which a mixture of fiber suspension and gas bubbles are jtted into a flotation tank in an upwardly directed manner toward the free surface of the pulp at a velocity of greater than Sm/s and the jet ends at or just below the free surface of the mixture.

Abstract: Screw feeders are disclosed including a conical feed screw rotatably disposed in a conical screw tube, and a drive shaft mounted at one end of the conical feed screw with a pair of bearings mounting the drive shaft, a fixed ring mounted on the drive shaft, and an axially adjustable sleeve mounted on the drive shaft, with the pair of bearings disposed between the fixed ring and the axially adjustable sleeve in order for the pair of bearings to be pretensioned therebetween.

Abstract: Methods for the continuous production of compressed board are disclosed including drying lignocellulosic fibrous material, gluing the lignocellulosic fibrous material, forming a mat, and pre-compressing the mat by controllably adding steam to the mat in an amount such that the temperature of the mat is increased to between about 60 and 90.degree. C.

Abstract: Methods of manufacturing board products include the steps of drying lignocellulosic material in a first stage dryer, further drying the lignocellulosic material in a second stage dryer, forming the dried lignocellulosic material into a mat, hot pressing the mat, utilizing the pressed air stream from the hot pressing step and a supply of fresh air as the source of drying air for the first and second stage dryers, utilizing the exhaust air from the second stage dryer as a source of drying air for the first stage dryer, and utilizing the exhaust air from the first stage dryer as a source of drying air for the first stage dryer and as a source of combustion air in a furnace.

Abstract: Methods for separating metal ions from pulp material are disclosed including treating the pulp with a chelating agent to produce a pulp flow with dissolved metal ions, washing that pulp flow prior to bleaching with hydrogen peroxide or ozone and mixing the washed liquid containing metal ions with another flow of lignocellulose-containing material in order to bind the metal ions to that flow, washing that flow, and subsequently washing that flow at a reduced pH to produce a wash flow containing metal ions.

Abstract: Apparatus for sealing a roll press including a seal extending along at least one of a pair of press rolls, the seal including a resilient member extending from the vat in which the press rolls are disposed towards one of the press rolls and a wear member attached to the resilient member for contacting the outer shell surface of the vat press roll whereby the wear member can be replaced upon wearing down of same.

Abstract: Apparatus for refining lignocellulose material is disclosed including two relatively rotatable refining disks separated by a refining gap which includes an inner radial portion and an outer angular portion, with the refiner elements mounted on the outer angular portions of the refiner disks including at least one wing projecting from the rotatable refining disk adjacent to the inner radial refining gap and with the stationary refining disk including a concave surface at the inlet portion so that the lignocellulose material being processed is thrown against the concave surface during its transition from the inner radial refining gap to the outer angular refining gap.

Abstract: Methods for the continuous production of compressed board from lignocellulosic fibrous material are disclosed. The methods include providing the lignocellulosic fibrous material in the form of particles or fibers, drying, gluing and forming the lignocellulosic fibrous material into the form of a mat, and compressing the mat in the presence of steam in a single step which includes applying a compression roller to the mat and applying steam through the compression roller.

Abstract: Apparatus for screening pulp suspensions containing heavy impurities is disclosed including a casing with an inlet for the pulp suspension at the lower end of the casing, a stationary screen mounted within the casing, a rotor mounted for rotation within the stationary screen thus forming a screening zone between the rotor and the stationary screen, with the inlet disposed within the rotor, the rotor including at least one opening adjacent to its upper end for transferring the pulp into the screening zone and a chamber for the heavy impurities disposed adjacent to either the upper or lower end of the casing, the rotor including strips or grooves for moving heavy impurities from the inner surface of the rotor to the chamber.

Abstract: Methods for washing sawdust are disclosed which include providing a mixture of sawdust and water to a vessel, subjecting the mixture to a reduced pressure so that gases present in the sawdust cause expansion therein and the sawdust rises to the surface of the mixture while the contaminants descend within the vessel, and withdrawing the sawdust from the vessel, in which the sawdust is withdrawn from the vessel at a location above the point where the sawdust and water enter the vessel. Apparatus for carrying out this method is also disclosed.

Abstract: Apparatus is disclosed for dewatering pulp suspensions including a pair of cylindrical rotatable liquid-premeable press rolls forming a nip therebetween, so that the material suspension can pass between the nip to be dewatered and to form a material web, a pair of doctor blades disposed below the nip, each associated with one of the press rolls for removing the material web therefrom, and a sealed casing enclosing at least the upper portion of the pair of press rolls, the sealed casing including an inlet for the material suspension, and the pair of doctor blades being coupled together so that they are movable relative to the nip in order to alter the distance between the pair of doctor blades and the nip when the size of the nip is adjusted.

Abstract: Apparatus for separating light impurities from a pulp suspension is disclosed. The apparatus includes a housing mounted on a fractionation device and symmetrically disposed with respect to the axis of rotation of the casing of the fractionation device, a passageway extending between the housing and the casing, and in which the top of the housing includes an outlet for the light impurities and a dilution liquid inlet for injecting dilution liquid tangentially into the housing.

Abstract: Apparatus for treating wash water is disclosed. The apparatus includes a settling tank in which sludge is separated from the wash water, a circulation tank for temporary storage of the clean wash water from the settling tank, and from which the clean wash water can be recycled for washing further chips, and a hydrocyclone for separating water from the sludge for recycle to the settling tank. Methods for treating wash water utilizing such apparatus are also disclosed.

Abstract: A method of producing mechanical and chemi-mechanical pulp with a yield above 85 % from lignocellulose-containing material for the manufacture of paper or board products. The material is subjected to mechanical processing in at least two steps. The material at its feed into the first step has a temperature below the softening temperature of lignin. When the material is fed into at least one subsequent processing step, it shall have a temperature above the softening temperature of lignin.

Abstract: Apparatus for pressing wet-formed fiber material boards in a multi-stage press is disclosed, including a vertically movable loading elevator with several stages for receiving transport plates for the boards, and a pusher for moving the transport plates from the loading elevator into the press. A hydraulic system is provided for driving both the loading elevator and the pusher.

Abstract: Methods and apparatus for manufacturing wrapping sheets from a pulp web are disclosed. The disclosed method includes drying the pulp web, embossing the dry pulp web by providing a plurality of raised portions on the surface of the dried pulp web, cutting the pulp web into sheets, and forming a stack of sheets of the pulp web. Apparatus for carrying out this method is also disclosed.