Patents Assigned to A. Ahlstrom Corporation
  • Patent number: 4969930
    Abstract: An apparatus for gasifying solid carbonaceous material in a circulating fluidized bed reactor. Particles are separated from the product gas at least in two stages so that in the first stage mainly coarser, so-called circulating particles are separated and returned to the reactor. In the second stage fine carbonaceous and ash-containing particulates are separated from the gas and are made to agglomerate at a raised temperature. Coarser particles thus received are returned to the reactor through a return duct together with circulating particles. Agglomeration is effected in a chamber where a fluidized bed composed of coarse particles is maintained. Fine particulate material and oxygen containing gas are introduced into the free upper part of the chamber so as to form a hot flame (e.g. 1200.degree. C.). The point of the flame penetrates into the fluidized bed. The ash material contained in the fine particulate material melts, and is conducted to the bubbling fluidized bed.
    Type: Grant
    Filed: February 8, 1990
    Date of Patent: November 13, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Olli E. Arpalahti
  • Patent number: 4964950
    Abstract: A method and an apparatus for dividing and uniting flows of high-consistency fibre suspensions. To prevent clogging of the distributor the fibre suspension is caused to flow into a space unitting the inlet and the outlet flows, where a turbulent flow extending to the valves regulating the discharge flow is created. The distributor includes a vortex chamber provided with an inlet and outlets and with regulating valves connected to the outlets and disposed at a short distance from the outlets. According to a preferred embodiment of the the invention, a rotor provided with vanes is disposed in the vortex chamber.
    Type: Grant
    Filed: August 20, 1986
    Date of Patent: October 23, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Toivo Niskanen, Voitto Reponen
  • Patent number: 4957778
    Abstract: A chemically self-copying paper intended for use in the combinations of a top sheet (CB), bottom sheet (CF) and one or more interleaving sheets (CFB) or a chemically copying, self-containing paper. The paper is formed of two fiber layers manufactured in separate wire sections and couched together while wet. The wire side of the upper fiber layer and the top surface of the lower fiber layer are couched together. The components inducing the color reaction are contained in the upper fiber layer which has been in contact with a smooth-surfaced press roll during the production of the paper.
    Type: Grant
    Filed: July 14, 1989
    Date of Patent: September 18, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Olavi A. Yrjala
  • Patent number: 4952314
    Abstract: An apparatus for treating, e.g., washing or filtering, fiber suspensions having a consistency of 8-20%, the apparatus including at least on rotatable filtering surface, an arrangement for feeding the suspension to a treatment region of the apparatus, and an arrangement for discharging the suspension from the treatment region, the feeding arrangement including at least one pressure chamber for fluidizing the suspension, at least one inlet duct for introducing the suspension to the chamber, and at least one feed duct for transferring the suspension from the pressure chamber to the treatment region.
    Type: Grant
    Filed: July 26, 1988
    Date of Patent: August 28, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Kaj O. Henricson, Seppo K. Kokkonen, Olavi E. Pikka, Harri T. Qvintus, Erkki A. Ruuskanen, Erkki E. Savolainen
  • Patent number: 4949474
    Abstract: A method and apparatus for drying particulate material such as bark by forming a circulating bed of other material to be dried, which bed, being guided by wires, moves on an endless web around two wire turning rolls. Material to be dried is continuously fed onto the bed and dried material is continuously discharged from the innermost layers of the bed, such that the thickness of the bed remains constant. The material to be dried is discharged by means of a dosing cell roll, which is disposed in the opening between the horizontal section of the first wire loop and the horizontal section of the second wire loop.
    Type: Grant
    Filed: November 7, 1989
    Date of Patent: August 21, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Eero Berg
  • Patent number: 4950402
    Abstract: An apparatus for screening pulp comprises a vessel, a cylindrical screen within the vessel, a rotor moving in the vicinity of the screen at a predetermined speed, an inlet for the unscreened pulp, an outlet for the screened pulp in the vessel. The rotor is non-cylindrical, for instance, elliptical, triangular and, in general, is multi-cam. The rotor has a contour surface, for instance grooves formed of a first bottom plane parallel to the envelope surface, an inclined plane, an upper plane and a side plane, the side plane being essentially perpendicular to the first bottom plane, the inclined plane forming an angle between 5 degrees and 60 degrees with the first plane, the upper plane being parallel to the first plane. The contour surface of the rotor may also be achieved by attaching bars of the contoured shape to the surface of the rotor, for instance by welding.
    Type: Grant
    Filed: October 3, 1988
    Date of Patent: August 21, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Frey Frejborg
  • Patent number: 4944467
    Abstract: The present invention relates to an apparatus for decelerating the jumbo roll of a paper or a board manufacturing machine in order to minimize the time required for a reel drum exchange and the amount of paper or board wasted as the jumbo roll slackens. The apparatus comprises brake shoes (9, 11) and arms (8) provided with means (13) producing the decelerating force. The arms can simultaneously transfer and decelerate the jumbo roll (2) whereby also a loop in the web is formed rapidly and easily.
    Type: Grant
    Filed: February 27, 1987
    Date of Patent: July 31, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Keijo K. Snygg
  • Patent number: 4943372
    Abstract: The present invention relates to a method and apparatus for discharging a disc filter. The method and apparatus are excellent for handling fiber suspensions in the pulp and paper industry. In earlier known means, the filter cake thickened on the filter surfaces of the disc filter is detached by means of water or compressed-air jets and the cake allowed to freely fall to an axial chute disposed below the shaft level of the filter, wherefrom the pulp most usually is transferred by means of a screw conveyor. The pulp, however, easily clogs the inlet opening of the chute, whereby pulp material accumulates in the space between the discs with harmful consequences.
    Type: Grant
    Filed: November 1, 1988
    Date of Patent: July 24, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Raimo Kohonen
  • Patent number: 4942769
    Abstract: The loading capacity of a core manufactured by reeling and gluing from paper or board layers, is tested by dynamically loading the core under conditions that simulate real life conditions. The core is mounted on a chuck, and the method is practiced by loading the core by utilizing a roll that exerts a nip pressure, and by rotating the core. One or both of the loading and the speed of rotation of the core are changed over time in a predetermined manner, to simulate the real life conditions. For example the loading on the core can be increased constantly while the rotational speed is kept constant, or the rotational speed is increased and the loading decreased corresponding to the real use situation caused by unwinding of a paper roll which is mounted by the core. The method also includes detecting any changes in the structure of the core, either optically, by sensing vibrational changes, or by sensing the break of an electrical wire passing through the core. Loading is continued until the core breaks.
    Type: Grant
    Filed: September 8, 1988
    Date of Patent: July 24, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Markku S. Jarvinen, Mikael J. H. Novaky, Heikki P. J. Rommi
  • Patent number: 4940007
    Abstract: In a fast fluidized bed reactor having, in a lower region, downwardly and inwardly inclined walls, a change in the direction of the wall surface or a ledge or protrusion is provided to change the direction of the particles flowing downwardly adjacent the wall for directing the particles inwardly away from the wall and into the region acted on by the nozzles providing the fluidizing gas. The change of direction, abutment or projection is preferably provided along the refractory wall surface at an elevation 200-1100 mm above the grid plate. In this manner, clogging of the nozzles is prevented and more efficient and effective fluidization and combustion processes occur.
    Type: Grant
    Filed: August 16, 1988
    Date of Patent: July 10, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Matti Hiltunen, Ragnar Lundqvist, Juha Sarkki
  • Patent number: 4936592
    Abstract: The present invention relates to a sealing arrangement for sealing a rotary shaft by means of several adjacent ring-type packings arranged in a packing box. The disadvantage of known arrangements is that, in box-type sealings, only the packing rings disposed nearest to the clamping element are clamped effectively. In the arrangement of the invention, an intermediate gland (11) is arranged between packing rings (8, 9) and said intermediate gland is forced to move to the left while the screws (13) are being screwed up. The desired effect is achieved by providing the ends of each screw (13) with divergent threads (16, 17), which are provided with an unequal or equal pitch.
    Type: Grant
    Filed: May 24, 1988
    Date of Patent: June 26, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Kalevi Vaisanen
  • Patent number: 4934281
    Abstract: A circulating fluidized bed reactor comprises a separator including a vortex chamber adjacent the top of the reactor for separating solid material from the flue gases of the reactor. A channel directs flue gases discharged from the reactor and adjacent the top of the reactor in a downward direction. A main portion of the solid material is separated from the gases by a change of flow direction after which the solid material is returned to the lower part of the reactor. The main portion of the gases is directed, after the change of direction, to the vortex chamber where further separation of solid material is effected and the separated solid material is returned to the reactor.
    Type: Grant
    Filed: October 27, 1988
    Date of Patent: June 19, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Folke Engstrom, Kaj O. Henricson, Ragnar G. Lundqvist
  • Patent number: 4932363
    Abstract: A fluidized bed reactor includes a reactor chamber, a solids separator and means for returning the separated solids to the reactor chamber. The separator has a separation chamber (7) which comprises a curved upper wall (9) and a lower wall (10) which forms gas outlets (13), said walls being connected to a solids returning duct (11). Preferably the lower wall forms a plurality of inclined surfaces or chutes (35) slanted downwardly towards the solids returning ducts (31).
    Type: Grant
    Filed: November 21, 1988
    Date of Patent: June 12, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Reijo J. Kuivalainen
  • Patent number: 4930387
    Abstract: A circular saw has adjustable blades mounted on a splined blade arbor. A guide engages a portion of each blade spaced from the blade arbor so as to facilitate movement of the blade along the blade arbor without tilting or canting. The guides are mounted on a guide arbor. Each blade and associated guide are connected to an actuator by shifter bars which are slideably disposed in the splines. The actuator comprises a connecting plate, each connecting plate being provided with a shifting cylinder for effecting movement of the mounting plate and associated simultaneous displacement of an equal amount by the blade and guide associated with it. Preferably three round shifter bars disposed in half-round splines circumferentially spaced 120.degree. from each other are associated with each blade and guide. The mounting plates are disposed on shafts having gear wheels at their opposite end cooperating with racks.
    Type: Grant
    Filed: June 20, 1989
    Date of Patent: June 5, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Lauri O. Miettinen
  • Patent number: 4929307
    Abstract: A method of decreasing the viscosity and improving the evaporability of sulfate black liquor from the cellulose cook includes raising the temperature of the black liquor above the cooking temperature so as to split the macro-molecular lignin fraction contained in the liquor. The temperature of the black liquor is maintained at the raised level for 1 to 60 minutes, preferably for 1 to 5 minutes.
    Type: Grant
    Filed: February 17, 1989
    Date of Patent: May 29, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Erkki J. Kiiskila, Nils E. Virkola
  • Patent number: 4929255
    Abstract: A method for gasifying or combusting solid, carbonaceous material in a circulating fluidized bed reactor. Particles are separated from the product gas at least in two stages so that in the first stage, mainly coarser, so-called circulating particles are separted and returned to the reactor. In the second stage, fine carbonaceous particlates are separated from the gas and are made to agglomerate at a raised temperature. Coarser particles thus recieved are returned to the reactor through a return duct together with circulating particles. Adhesion of agglomerating particles to the walls of the duct is prevented preferably by leading hot particulates to the center of the duct and circulating particles to the walls of the duct.
    Type: Grant
    Filed: August 23, 1988
    Date of Patent: May 29, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Bertel K. Hakulin, Jorma J. Nieminen
  • Patent number: 4927529
    Abstract: A method of and apparatus for separating knots from a fibre suspension in the wood processing industry. A known problem in the prior art has been the quick wear of the screen surface of the knotter when the screen surface has been profiled. On the other hand the ability to separate with an unprofiled screen has not been satisfactory. When using a profiled screen cylinder (5), it has been noticed in performed tests that it is preferable to feed the pulp from the connections (2) in the direction of rotation of the screen cylinder and also to discharge the reject from connections (4) and the accept from the connections (3) in the direction of rotation of the cylinder (5). Accordingly, there is not only less wear of the screen surface, but also a significantly smaller consumption of power per pulp ton than in the prior art apparatuses.
    Type: Grant
    Filed: January 19, 1988
    Date of Patent: May 22, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Kaj O. Henricson, Erkki T. Repo, Hannu U. Ronkonharju
  • Patent number: 4925526
    Abstract: A falling film evaporator having vertical outer tubes with closed upper ends connected to an upper tube plate disposed in the lower region of the evaporator. Other parallel tubes are disposed inside the outer tubes and are connected to a lower tube plate under the upper tube plate. The evaporator also has a mechanism for distributing the material to be evaporated onto the upper ends of the outer tubes in such a way that the material flows down along the tubes and forms a film on the external surface of the tubes. The space between the tube plates, in which the ends of the outer pipes are located, is divided by an intermediate wall into an inlet and an outlet compartments. Heating steam is fed to the inlet compartment. Clean condensate is recovered from the inlet compartment and contaminated condensate from the outlet compartment.
    Type: Grant
    Filed: October 3, 1988
    Date of Patent: May 15, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Reino I. Havukainen
  • Patent number: 4921400
    Abstract: A centrifugal pump and a method of separating gas from a gas containing liquid-solids suspension. The method and apparatus of the invention is especially suitable for pumping of fiber suspensions in the pump and paper industry. The pump includes a suspension chamber having a suspension inlet and a suspension outlet, a gas chamber in fluid communication with the suspension chamber and a perforated surface located between the suspension chamber and the gas chamber for substantially preventing the solids from passing into the gas chamber.
    Type: Grant
    Filed: July 6, 1988
    Date of Patent: May 1, 1990
    Assignee: A. Ahlstrom Corporation
    Inventor: Toivo Niskanen
  • Patent number: RE33230
    Abstract: A fluidized bed reactor (1) comprising a reactor chamber (4) having a gas distributor plate (5) for feeding primary air, and a space above said distributor plate (5) is divided into compartments (6) by means of partition walls (7) having discharge openings (9) for feeding secondary air to the circulating bed.
    Type: Grant
    Filed: February 22, 1989
    Date of Patent: June 12, 1990
    Assignee: A. Ahlstrom Corporation
    Inventors: Folke Engstrom, Juhani M. Isaksson, Reijo Kuivalainen