Patents Assigned to A. Ahlstrom Corporation
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Patent number: 4827711Abstract: In a gas turbine process in which hot moist gas produced by combusting natural gas and injecting steam to the combustion device, the relative moisture content of the gas is reduced after the turbine by adiabatic absorption by means of an absorbent liquid the only evaporating component of which is water. The condensation heat of the aqueous steam condensed in the absorption is to a large extent conveyed to the gas the temperature of which is thereby raised. The heat is recovered by known methods for use e.g. in district heating. The diluted absorbent liquid is regenerated for example by arranging it in the heat recovery stage before the absorption in indirect heat exchange contact with the gas.Type: GrantFiled: October 29, 1987Date of Patent: May 9, 1989Assignee: A. Ahlstrom CorporationInventor: Matti J. Isaksson
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Patent number: 4827723Abstract: The system includes a circulating fluidized bed combustor coupled at its outlet to a separator. A vertical return channel is provided for conveying separated solid particles from the separator back to the combustion chamber. A gas turbine cycle is provided, including a gas compressor, a heat transfer means directed to a first duct to the compressor for heating the compressed oxidizing gas, a gas turbine connected through a second duct to the heat transfer means for power generation and a third duct for conveying expanded oxidizing gas from the turbine to the combustion chamber. The heat transfer means includes tubes disposed inside the vertical return channel for indirect heat transfer between the compressed gas and the dense suspension of separated particles flowing downwardly in the vertical channel.Type: GrantFiled: February 18, 1988Date of Patent: May 9, 1989Assignee: A. Ahlstrom CorporationInventors: Folke Engstrom, Juhani M. Isaksson
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Patent number: 4817856Abstract: A pump impeller is coated essentially without use of core structures. The pump impeller coating is performed in several stages. Partial units of the impeller are coated, whereafter the coated partial units are assembled together. Exposed areas of the impeller are then coated to provide a continuous coating over the entire impeller.Type: GrantFiled: July 31, 1987Date of Patent: April 4, 1989Assignee: A. Ahlstrom CorporationInventors: Pauli A. T. Koistinen, Seppo T. Tolonen
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Patent number: 4813380Abstract: Solids are separated from the flue gases of a fluidized bed reactor with a circulating bed and provided with cooling surfaces and are recycled to the reactor through return ducts disposed at different heights in the reactor. To control the operation of the reactor the heat removed from the reactor chamber is regulated by changing the suspension density in the reactor chamber. A required suspension density is obtained by regulating the flow of the solids through each return duct.Type: GrantFiled: November 24, 1987Date of Patent: March 21, 1989Assignee: A. Ahlstrom CorporationInventor: Folke Engstrom
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Patent number: 4812207Abstract: A method of removing lignin from bleach plant effluents by using cellulose fibres. The method comprises an acidous phase during which sludge containing cellulose fibres is added to the acidous effluent, and an alkaline phase during which alkaline waste water is added to the effluent-sludge solution. A portion of the produced fraction containing fibres is recirculated to the acidous phase for reuse of the fibres.Type: GrantFiled: November 18, 1987Date of Patent: March 14, 1989Assignee: A. Ahlstrom CorporationInventors: Johan Gullichsen, Pertti Hynninen
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Patent number: 4793292Abstract: A circulating fluidized bed reactor includes a filter apparatus for separation and recycling of fine particles which are entrained by the flue gas. The housing of the filter apparatus has a plurality of vertically disposed ceramic filtration tubes. The reactor chamber and filter housing are arranged back-to-back and have a common wall therebetween. A pre-separator for separation of coarse particles is provided which connects the reactor chamber with the filter apparatus. The reactor, the separator and the filter apparatus are encased in a pressure-proof cylindrical vessel. The walls of the reactor chamber and the filter housing are water-cooled.Type: GrantFiled: July 13, 1987Date of Patent: December 27, 1988Assignee: A. Ahlstrom CorporationInventors: Folke Engstrom, Juhani Isaksson
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Patent number: 4784726Abstract: A paper machine head box includes perforated plates being used as a distributor and a turbulence generator and having flow ducts, of which the ones at the edges are of different size than the remaining flow ducts. According to a preferred embodiment, slides, which are movable sideways, are provided at the ends of slice ducts at both edges of the perforated plates in order to regulate the flow. The slides and the perforated plates define the outermost flow ducts of the turbulence generator and the distributor.Type: GrantFiled: December 16, 1986Date of Patent: November 15, 1988Assignee: A. Ahlstrom CorporationInventor: Osmo Evalahti
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Patent number: 4778122Abstract: A method of charging reel drums (4) of a paper or a board manufacturing machine winder to the front end of a store (12) disposed on top of the winder; and of lowering the reel drums (4) from the store (12). During the charge of the reel drums (4) to the store, the reel drums (4) already in the store (12) are pushed from the front end (13), i.e. loading and discharge end of the store towards the rear end at least by a distance (D) equal to the diameter of the reel drum (4). When a reel drum (15) is lowered, the drums (4) which are in the store displaced at a distance equal to the reel drum diameter from the front end (13) of the store (12), are kept in place.Type: GrantFiled: February 27, 1987Date of Patent: October 18, 1988Assignee: A. Ahlstrom CorporationInventor: Keijo K. Snygg
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Patent number: 4776957Abstract: An apparatus for screening pulp comprises a vessel, a cylindrical screen within the vessel, a rotating element 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 rotating element 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-60 degrees with the first plane, the upper plane being parallel to the first plane. The rotating element may be a rotor or blade type segments. The rotor is located on the inlet side of the screen but the contour surface of the screen may be the outer or the inner surface of the screen drum. Also the screen has a contour surface which may have different configurations.Type: GrantFiled: April 22, 1987Date of Patent: October 11, 1988Assignee: A. Ahlstrom CorporationInventors: Harry Lampenius, Frey Frejborg
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Patent number: 4771712Abstract: A method of burning solid fuel having low melting point alkaline compositions, such as alkali metal salts, particularly lignite and salty brown coal. The fuel is introduced into the reaction chamber of a circulating fluidized bed reactor, and is mixed prior to introduction to the reaction chamber with a reactant material capable of reacting with the low melting point alkaline compositions of the fuel to produce high melting point alkali metal compounds during combustion. The temperature in the reaction chamber is kept below the melting point of the formed alkali metal compounds. The reactant material comprises silica oxide or a metal oxide, or hydroxide, of the group consisting of aluminum, calcium, magnesium, iron, titanium, and mixtures of two or more thereof. Kaolin is particularly effective, especially when the molar ratio of Al/(Na and K) is at least 1.0.Type: GrantFiled: June 24, 1987Date of Patent: September 20, 1988Assignee: A. Ahlstrom CorporationInventors: Folke Engstrom, Erkki Kiiskila, Pekka Tormikoski
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Patent number: 4769111Abstract: The present invention relates to a support apparatus of a dewatering unit (30) below a bottom wire of the twin wire forming section of a paper or board machine.The problem in known, corresponding arrangements has been insufficient crosswise stiffness of the dewatering unit and lack of adjustability.The above-mentioned disadvantages have been eliminated or minimized by a support arrangement, characterized in that the dewatering unit (30) is supported on beams (36) transversely in view of the machine direction by means of a hose-like pressure-medium filled elements (37), which also allow a longitudinal adjustment of the dewatering unit by means of an adjusting element (38).Type: GrantFiled: July 2, 1987Date of Patent: September 6, 1988Assignee: A. Ahlstrom CorporationInventors: Taisto A. Nevalainen, Tapani E. Nyman
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Patent number: 4755134Abstract: The invention relates to a circulating fluidized bed reactor comprising a particle separator (9) having a horizontal vortex chamber (23). The separator is preferably disposed on top of the combustion chamber (5). The pipes (25) discharging gas from the vortex chamber have been connected to openings (24) disposed on the periphery (19) of the vortex chamber.Type: GrantFiled: May 8, 1987Date of Patent: July 5, 1988Assignee: A. Ahlstrom CorporationInventors: Folke Engstrom, Ragnar G. Lundqvist
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Patent number: 4753019Abstract: An apparatus for drying and heating lime sludge in a rotary kiln by means of regenerative heat transfer. The apparatus is preferably formed of round or rounded rods which extend parallel to the longitudinal axis. The rods are disposed in the kiln in an annular region adjacent the housing wall so that lime sludge flows freely between the rods while the kiln is rotating.Type: GrantFiled: December 30, 1986Date of Patent: June 28, 1988Assignee: A. Ahlstrom CorporationInventor: Osmo Holopainen
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Patent number: 4753177Abstract: 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: GrantFiled: April 30, 1987Date of Patent: June 28, 1988Assignee: A. Ahlstrom CorporationInventors: Folke Engstrom, Juhani Isaksson, Reijo Kuivalainen
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Patent number: 4747852Abstract: A method and an apparatus for separating coarse and fine solid particles from flue gases in a circulating fluidized bed reactor provide for flue gases to be led to a cyclone separator, located adjacent the reactor. A discharge opening is provided in the lower portion of the separator, opening into a suction chamber interposed between the discharge opening and a return duct. Coarse particles are returned to the reactor via the return duct while fine particles are pulled into a suction pipe connected to the suction chamber, and are then returned to the reactor separately from the coarse particles. At the same time, a minor portion of the flue gases are removed through the discharge opening in the separator with the solid particles and returned to the reactor. The major portion of the flue gases is discharged through an opening in the upper portion of the separator.Type: GrantFiled: August 25, 1986Date of Patent: May 31, 1988Assignee: A. Ahlstrom CorporationInventor: Folke Engstrom
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Patent number: 4738835Abstract: A method of recovering alkaline chemicals from a material containing sodium or potassium compounds. The material is gasified by an external heat source after which the gas is rapidly cooled by arranging it to contact with cooled solid particles separated from the gas.Type: GrantFiled: December 16, 1986Date of Patent: April 19, 1988Assignee: A. Ahlstrom CorporationInventor: Erkki J. Kiiskila
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Patent number: 4733621Abstract: A fluidized bed reactor has a pair of cyclone separators which receive flue gas with entrained solids and wherein the solids are separated from the flue gas in the separators for flow into a fluidized distribution conduit. The flow of separated particles is divided into two particle streams and fluidizing air is introduced into the duct. The fluidized separated particles are then conveyed to the combustion chamber of the reactor through an upright conduit in turn connected to a downwardly inclined conduit connecting the combustion chamber with the fluidized separated particles in the duct. The downwardly inclined conduits are substantially equidistantly distributed along the lateral extent of the combustion chamber to provide even distribution of the solid separated particles with fuel mixed therein in the combustion chamber.Type: GrantFiled: May 8, 1987Date of Patent: March 29, 1988Assignee: A. Ahlstrom CorporationInventors: Markku Kostamo, Martti Puhakka
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Patent number: 4732113Abstract: A separator for separating solid particles from a hot gas stream comprises a cyclone chamber having an axial gas outlet conduit. The outlet conduit is formed by a plurality of cooling tubes defining between the tubes a plurality of passages for the gas. The outlet conduit is connected to an opening in one or both ends of the cyclone chamber. Solids are separated by centrifugal forces as the gas flows in a curved path in the cyclone chamber and by inertia forces as the gas changes direction to flow into the outlet conduit.Type: GrantFiled: March 9, 1987Date of Patent: March 22, 1988Assignee: A. Ahlstrom CorporationInventor: Folke Engstrom
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Patent number: 4729837Abstract: A method and apparatus for thickening a pulp, in particular a pulp containing fibres. The pulp is thickened hydraulically while it flows through a space between two screen surfaces. Thickening on alternate screen surfaces is prevented for cleaning by closing the valves in the outlets. Pulp is removed from the screen surfaces by vanes.Type: GrantFiled: May 5, 1986Date of Patent: March 8, 1988Assignee: A. Ahlstrom CorporationInventor: Kaj O. Henricson
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Patent number: 4708092Abstract: The invention comprises a circulating fluidized bed boiler having a vertical combustion chamber and a convection part which at least partly are formed by tube walls, and a horizontal cyclone separator, the gas inlet channel of which is connected to the upper part of the combustion chamber and a return channel for solids to the lower part of the combustion chamber. In order to accomplish a compact construction, the cyclone separator has been located on top of the combustion chamber and two opposite tube walls of the combustion chamber and possibly also one tube wall of the convection part have been used to form the cyclone separator.Type: GrantFiled: September 22, 1986Date of Patent: November 24, 1987Assignee: A. Ahlstrom CorporationInventor: Folke Engstrom