Patents Assigned to A. Ahlstrom
  • Patent number: 6375795
    Abstract: The release of malodorous TRS-containing gases from a comminuted cellulosic fibrous material feed system for a digester is minimized utilizing a particular arrangement associated with a pressure isolation device. Material is fed through the pressure isolation device and the pressure of the material increases from the inlet to the outlet, and the material is discharged from the pressure isolation device into a treatment vessel, such as a horizontal steaming vessel. Malodorous gases from the pressure isolation device are discharged substantially independently of the material discharged from the isolation device, and at least some of the malodorous gases discharged from the pressure isolation device are pressurized (e.g. in an eductor or thermocompressor) and reintroduced into the flow of cellulosic material downstream of the pressure isolation device (for example into the horizontal steaming vessel or a vessel downstream of it).
    Type: Grant
    Filed: December 1, 2000
    Date of Patent: April 23, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: David J. Lebel, Todd S. Grace
  • Patent number: 6368698
    Abstract: A printed circuit board is made from at least one non-woven sheet or web layer comprising at least 50% by weight acrylic fibers, with any balance substantially electrically non-conductive fibers, filler, and binder. The sheet or web is preferably made by the foam process, and may contain 60-80% straight polyacrylonitrile fibers and 40-20% fibrillated (pulp) ones. The web or sheet is preferably compressed by thermal calendering so that it has a density of about 0.1-1 grams per cubic centimeter; and the web or sheet may have a basis weight of between about 20-120 grams per square meter. The web or sheet may also have a 1-40% of substantially electrically non-conductive organic or inorganic binder, or may be substantially binder free.
    Type: Grant
    Filed: May 19, 2000
    Date of Patent: April 9, 2002
    Assignee: Ahlstrom Glassfibre Oy
    Inventors: Kay Rokman, Rod Komlenic, Kelly Rennels, Hakan Sabel
  • Patent number: 6358363
    Abstract: A method and apparatus for bleaching medium consistency pulp with ozone using at least 2 fluidizing mixers to mix ozone and carrier gas into the pulp. The method is particularly applicable when the volume of the bleaching gas is larger than the volume used in conventional ozone bleaching, e.g. 2 m3/adt.
    Type: Grant
    Filed: April 18, 1996
    Date of Patent: March 19, 2002
    Assignee: Andritz-Ahlstrom Oy
    Inventor: Kaj Henricson
  • Patent number: 6354514
    Abstract: A method and an apparatus for heating or cooling material having poor thermal conductivity, especially medium-consistency fiber suspensions. The material is directed, substantially as a plug flow, at a velocity below 5 m/s (e.g. 0.1-1 m/s) through an apparatus formed by a flow channel provided with heat exchange surfaces. The flow of the material is throttled at a throttling point by a more than 30% reduction in the cross-sectional area of the channel. After throttling, the material is discharged from the throttling point in such a manner that another portion of the material contacts the heat exchange surfaces.
    Type: Grant
    Filed: June 14, 2000
    Date of Patent: March 12, 2002
    Assignee: Andritz-Ahlstrom Oy
    Inventors: Kaj Henricson, Kari Peltonen
  • Publication number: 20020026990
    Abstract: Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350° F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief).
    Type: Application
    Filed: October 19, 2001
    Publication date: March 7, 2002
    Applicant: ANDRITZ-AHLSTROM INC.
    Inventors: Jay J. Miele, Marco Marois, R. Fred Chasse, J. Wayne Chamblee, John D. Weston, J. Robert Prough
  • Publication number: 20020026991
    Abstract: Chemical pulp is produced from a slurry of comminuted cellulosic fibrous material using a beneficial additive such as AQ, or polysulfide. In the first treatment zone the effective alkali concentration and temperature conditions are such so that substantially no alkali degradation of the cellulose occurs, but so that the material is effectively impregnated with the additive. Then the material is treated with an alkaline cooking liquor, at cooking temperature, to produce a chemical cellulose pulp with higher yield or strength than if the low temperature, low alkali, additive pretreatment was not practiced. Typical alkali and temperature conditions in the first zone are less than 10 g/l expressed as NaOH; and between about 80-130° C., e.g. about 80-110° C. The first zone is preferably a feed system (which may include a separate impregnation vessel) for a continuous digester, while cooking is in a continuous digester.
    Type: Application
    Filed: November 15, 2001
    Publication date: March 7, 2002
    Applicant: ANDRITZ-AHLSTROM INC.
    Inventors: C. Bertil Stromberg, Joseph R. Phillips
  • Patent number: 6350348
    Abstract: A method of cooking pulp in an alkaline batch process (using one or more batch digesters) improves pulp bleachability. The wood material is supplied to the digester; the cellulosic material is pre-treated in the digester with a first liquor, the first liquor is displaced by a second liquor, the displaced first liquor is led to a further treatment, the cellulose material is treated with the second liquor, and the cooked pulp is removed from the digester. The second liquor is displaced as two consecutive parts, i.e. as strong black liquor and weak black liquor, and after cooling in a heat exchanger the strong black liquor thus obtained is fed into the digester as the first liquor in a subsequent batch (in the same, or a different, batch digester).
    Type: Grant
    Filed: July 19, 1999
    Date of Patent: February 26, 2002
    Assignee: Andritz-Ahlstrom Oy
    Inventors: Kaj Henricson, Auvo Kettunen, Hannu Ramark
  • Publication number: 20020017370
    Abstract: The strength properties of chemical cellulose pulp (particularly kraft pulp) are improved by substituting a cold impregnation soak for conventional impregnation procedures. After steaming, wood chips are soaked in an alkaline liquid at a temperature of about 80-110° C. (preferably 80-100° C., or 90-105° C.) for between one-half-72 hours (typically about 2-4 hours) at a pressure of about 0-15 bar (preferably about 1-5 bar), to dissolve at least about 8% of the wood (preferably about 10-20%) and at least about 15% of the lignin. The alkaline liquid used preferably contains sulfide (e.g. black liquor, green liquor, white liquor, or mixtures thereof), but almost any alkaline liquid having an alkali concentration of about 1.0 mole of NaOH/liter or less (typically about 0.75 m/l or less) is suitable. The wood chips are then raised to a cooking temperature of about 145-180° C. and cooked to produce the cellulose chemical pulp.
    Type: Application
    Filed: October 15, 2001
    Publication date: February 14, 2002
    Applicant: Andritz-Ahlstrom Inc.
    Inventors: Kaj O. Henricson, Aki Hannu Vilpponen, Hannu Olavi Ramark, Auvo Kimmo Kettunen, C. Bertil Stromberg
  • Patent number: 6346167
    Abstract: Kraft pulp of increased strength and bleachability may be produced with decreased consumption of effective alkali, and at a lower H factor, by keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook, including by extracting high DOM liquid from at least one part of a continuous digester and replacing it with much lower level DOM liquid. Existing pulp mills having two-vessel hydraulic, one-vessel hydraulic, or other systems may be retrofit to provide for extractions and additions of low DOM dilution liquor (including substantially DOM-free white liquor). Also, commercial size batch digesters (8 tons per day of pulp or more) can be operated with low DOM liquor to produce increased strength pulp. Using dilution with low DOM liquor also results in reduced H factor and effective alkali consumption, and increased bleachability.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: February 12, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: Bruno S. Marcoccia, J. Robert Prough, Richard O. Laakso, Joseph R. Phillips, Rolf C. Ryham, Jan T. Richardsen, R. Fred Chasse
  • Patent number: 6346166
    Abstract: By the utilization of a jet ejector (such as a thermocompresser) in a cellulose chemical pulp mill, it is possible to effectively increase the utilization of steam. The volume of steam from a flash tank which flashes black liquor from a pulp digester may be increased (e.g. at least about 10%), while the volume and temperature of the liquor discharged from the flash tank are decreased and its concentration increased, by operatively connecting the jet ejector to the steam discharge from a flash tank. The jet ejector is supplied with higher pressure steam from another source which can result in a low pressure or partial vacuum condition in the flash tank. The flash tank may be a single flash tank or one of a series of flash tanks, and an ejector can be associated with at least another flash tank in the series.
    Type: Grant
    Filed: June 6, 2000
    Date of Patent: February 12, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: Auvo K. Kettunen, Matti Lautala
  • Patent number: 6344112
    Abstract: A screen used in the production of cellulose pulp may be mounted in a digester to minimize traditional screen problems (including clogging) without introducing new problems. The screen comprises a screen plate having a plurality of slots formed in it with an inclination angle, which is 30-60° with respect to the bottom edge of the screen plate. The screen plate may comprise a plurality of parallel screen bars side-by-side, or an integral metal plate with slots formed in it. The slots have a width between 1-5 (e.g. 2-4) millimeters and a spacing between them of 3-9 millimeters.
    Type: Grant
    Filed: October 20, 1999
    Date of Patent: February 5, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventor: Lasse Hernesniemi
  • Patent number: 6340805
    Abstract: The present invention relates to a method of manufacturing a wire screen product which is especially suitable for screening fiber suspensions of the wood processing industry. It is a characteristic feature of the method according to the invention of manufacturing a wire screen product including screen wires disposed crosswire in relation to a support arranagement that includes at least one support wire, the screen wires and support wire being secured to each other such that, at the first stage, the screen wire is welded by a button spot weld to the support arrangement and, at the second stage, the screen wire is welded at another point to the same support structure.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: January 22, 2002
    Assignee: Andritz-Ahlstrom Oy
    Inventor: Risto Ljokkoi
  • Patent number: 6336993
    Abstract: A system and method for feeding a slurry of comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester also treat the material to remove metals before digestion. During pumping of the slurry with at least first and second series connected pumps, at or upstream of at least one of the pumps chemicals (acids and/or chelating agents) which dissolve the metals in the material are added, and preferably some of the liquid is removed so as to purge at least about 10% (e.g. about 20-80%) of the metals in the material. The metal removal preferably takes place substantially immediately before alkaline digestion.
    Type: Grant
    Filed: May 11, 2000
    Date of Patent: January 8, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventor: C. Bertil Stromberg
  • Patent number: 6336573
    Abstract: A bin or hopper, preferably with one-dimensional convergence, has a slot outlet at its bottom for discharging bulk solid particulate material (such as coal, wood chips, sugar, plastic pellets, etc.) to a screw in a trough. The screw has varying flight diameter, shaft diameter, and average pitch along its length to a discharge so as to provide substantially uniform material flow velocity distribution along the slot outlet. One or more flow rate adjusters may regulate flow of material being transported by the screw. Each flow adjuster may be a vertical plate with a substantially straight-across bottom curved about a substantially horizontal axis, or with a bottom two-dimensional curvature.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: January 8, 2002
    Assignee: Andritz-Ahlstrom Inc.
    Inventor: Jerry R. Johanson
  • Patent number: 6332542
    Abstract: Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slurry flow within it (which may be augmented by high speed liquid introduction), that is caused to turn in a radiused path, centrifugal force allows separation of the tramp material into a cavity beneath the radius transition without requiring any mechanical element to engage the slurry. Appropriate purges, baffles, and discharge mechanisms may be provided. Alternatively, a tramp material separator may be built into an otherwise conventional metering screw in a digester feed system, or one or more centrifugal separators can be provided downstream of the slurry pump in a chip slurry transport system or digester feed system.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: December 25, 2001
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: Vic L. Bilodeau, R. Fred Chasse, James R. Prough, C. Bertil Stromberg, Craig A. Walley
  • Publication number: 20010050130
    Abstract: A printed circuit board is made from at least one non-woven sheet or web layer comprising at least 50% by weight acrylic fibers, with any balance substantially electrically non-conductive fibers, filler, and binder. The sheet or web is preferably made by the foam process, and may contain 60-80% straight polyacrylonitrile fibers and 40-20% fibrillated (pulp) ones. The web or sheet is preferably compressed by thermal calendering so that it has a density of about 0.1-1 grams per cubic centimeter; and the web or sheet may have a basis weight of between about 20-120 grams per square meter. The web or sheet may also have a 1-40% of substantially electrically non-conductive organic or inorganic binder, or may be substantially binder free.
    Type: Application
    Filed: January 8, 2001
    Publication date: December 13, 2001
    Applicant: Ahlstrom Glassfibre Oy.
    Inventors: Kay Rokman, Rod Komlenic, Kelly Rennels, Hakan Sabel
  • Publication number: 20010047854
    Abstract: In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an agitator (if used), compared to prior art constructions are provided. A first transition, preferably a substantially smooth interior surface substantially frusto-conical transition, is provided between the first and second diameters. A second single-convergent transition may be provided above the first transition. A rotating agitator with at least two arms and associated paddles may be mounted for rotation in the transition about a substantially vertical axis for agitating the material in the transition. If desired, the transition may be moved, such as with a vibrator or oscillator. The invention is particularly suitable for pulp digesters and impregnation vessels.
    Type: Application
    Filed: July 9, 2001
    Publication date: December 6, 2001
    Applicant: Andritz-Ahlstrom Inc.
    Inventors: J. Robert Prough, Jerry R. Johanson
  • Publication number: 20010047853
    Abstract: In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an agitator (if used), compared to prior art constructions are provided. A first transition, preferably a substantially smooth interior surface substantially frusto-conical transition, is provided between the first and second diameters. A second single-convergent transition may be provided above the first transition. A rotating agitator with at least two arms and associated paddles may be mounted for rotation in the transition about a substantially vertical axis for agitating the material in the transition. If desired, the transition may be moved, such as with a vibrator or oscillator. The invention is particularly suitable for pulp digesters and impregnation vessels.
    Type: Application
    Filed: July 9, 2001
    Publication date: December 6, 2001
    Applicant: Andritz-Ahlstrom Inc.
    Inventors: J. Robert Prough, Jerry R. Johanson
  • Patent number: 6325888
    Abstract: Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350° F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief).
    Type: Grant
    Filed: August 31, 1995
    Date of Patent: December 4, 2001
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: Jay J. Miele, Marco Marois, R. Fred Chasse, J. Wayne Chamblee, John D. Weston, J. Robert Prough
  • Patent number: 6325890
    Abstract: A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using one or more slurry pumps located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge. A return line from the top of the digester may, but need not necessarily, be operatively connected to the one or more pumps and if connected to the pumps, the liquid in the return line may be cooled to a temperature at which it will not flash during handling. Recirculation loops may be established associated with one or all of the slurry pumps to facilitate startup.
    Type: Grant
    Filed: May 11, 2000
    Date of Patent: December 4, 2001
    Assignee: Andritz-Ahlstrom Inc.
    Inventors: J. Robert Prough, C. Bertil Stromberg, Tim S. Pease