Abstract: The present invention relates to a method of and an apparatus for treating pulp. The apparatus according to the present invention is especially suitable for carrying out bleaching processes of the wood processing industry and for separation of residual gases remaining in the suspension in the processes. The method of the present invention is characterized in that pulp at the consistency range of 8 to 20% is subjected to at least the following treatment steps in a closed pressurized process: feeding pulp with a pump to a chemical mixer; mixing chemicals with the pulp; introducing the pulp flow by means of the pressure of the pump to a process vessel; treating the pulp with chemicals in the process vessel; removing gases from the pulp in connection with the process vessel or after it in a closed pressurized separator; in the gas separation, preventing fibers from exiting with the gas; and guiding the pulp via a closed path to a following process step.

Abstract: An appratus for treating medium consistency pulp in connection with different treatment apparatuses, such as washers. According to the prior art the treatment of pulp, for example, the washing process, starts at a low consistency, approximately 1-3% so that it is necessary always to dilute pulp before washing, whereby the water consumption of the plant increases and the need of power in, for example, pumping and in the treatment generally increases. The present invention makes it possible to treat medium consistency pulp, because the feeding means is able to spread the pulp as an even layer on the perforated surface of the treating apparatus.

Abstract: An arrangement for discharging medium consistency pulp in connection with diffeent pulp treatment devices or apparatuses, the arrangement having a mass chamber, which is arranged between a screw discharging pulp from a pulp treating apparatus and a centrifugal pump transferring the pulp further so that both the screw and the pump are substantially at the same horizontal level with the pulp treatment apparatus. Thus, the presence of a drop leg having a height of several meters is prevented, whereby the centrifugal pump has no need to pump the pulp upwards back to the height of the pulp treatment apparatus.

Abstract: The present invention relates to a method and apparatus for the continuous discharge of water from suspension, especially from fibrous pulp, whereby pulp is caused to thicken without having the water to be removed through a thick uncontrollably gathered fiber mat.In accordance with the invention the suspension to be thickened is fed into a filtering chamber, the suspension is formed as a layer that is continuously being mixed for equalizing the consistency differences, the liquid is continuously removed from the suspension and the thickness of the fiber mat being formed on the filter surface is controlled by subjecting said mat to shear stresses.The above described method is realized by an apparatus, in which at least one of the co-operating surfaces, the filtering surface (8) and its counter surface (10), is provided with means (12) for non-mechanically limiting the thickness of a fiber mat on the filtering surface, whereby a uncontrolled formation of a fiber mat on the filtering surface (8) is prevented.

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.

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.

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.

Abstract: The present invention relates to a method and an apparatus for thickening of fiber suspension. In particular, the invention relates to removal of water from pulp which is caused to thicken in a closed space equipped with a fine-perforated or fine-slotted screen surface. The problem with the prior art devices has been their complex structure or, in simpler solutions, their great susceptibility to clogging. These problems have been found out to be overcome through dimensioning of perforations in the screen surfaces (28, 30; 38, 40) of the thickener and the flow channels (33; 37) between the filtering surfaces (28, 30; 38, 40) in such a way that the pulp flows in the channels as a plug flow, that is, the internal friction of the pulp is greater than the surface friction between the pulp and the screen surface.

Abstract: 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.

Abstract: Cellulose pulp or recycled paper is defiberized, screened and pumped. Initial defiberizing, separation of non-disintegrated material, final defiberizing and pumping of the defiberized pulp are performed at a consistency of 6 to 18%, preferably 8 to 12%. Preferably all operations are performed at the same consistency. A defiberizing rotor is disposed in front of an impeller in the inlet of a centrifugal pump. A screen plate is mounted close to the defiberizing rotor. Defiberizing elements are arranged on the other side of the screen plate to move close to the screen surface.

Abstract: Apparatus for washing fiber stock, comprising a substantially horizontally disposed rotating screen drum, means for supplying fiber stock to one end of said screen drum for passage along the screen surface through said screen drum, means for removing fiber stock from the other end of said screen drum, and a longitudinally extending liquid supply member fixedly mounted beneath the center axis of the screen drum, immersed in the fiber stock. The apparatus is provided with suction chambers and it acts as a screen with self-suction.

Abstract: A method for the recovery of heat and easily evaporable components from hot gases in which a liquid flowing downwards along heat exchanger surfaces is simultaneously heated indirectly, the hot gases are fed into the lower section of a gas space, blast gas containing evaporable components is removed at the upper section of the gas space, and a condensate derived from the hot gases is removed at the bottom of the gas space, comprising further bringing the blast gases into one or several indirect heat exchange contacts with the liquid, in successive additional gas spaces, recovering condensate accumulated at the bottoms of these additional spaces, and withdrawing the blast gases from the last additional gas space.