Abstract: The invention relates to a method and an apparatus for filtering process gas created in the ferroalloy smelting process, i.e. carbon monoxide gas, in order to essentially reduce the content of solids in the gas. In the filtering unit (24) gas containing solids is conducted through at least one filtering element (7), inert gas blowing (8) is directed to the filtering element (7) in order to detach the solid material from the surface of the filtering element (7), and in order to remove from the filtering unit (24) the solid material detached from the the surface of the filtering element (7) the solid material is slurried by means of liquid fed (11) into the filtering unit (24). The slurry containing the sold material is removed from the filtering unit (24) through a discharge chamber (12).

Abstract: The invention relates to a roller screen for screening pellets for sintering, the roller screen including several successive rotating rollers that are spaced apart and arranged transversally in relation to the proceeding direction of the material. The roller screen is provided with separate rotation motors for rotating each of the rollers and an adjusting member for adjusting the mutual position of the rollers in order to screen a desired particle size. The screen path of the roller screen is composed of three successive screening parts, which are mutually connected so that the rollers of the screening parts are made to rotate in relation to each other, and the speed of rotation of the roller increases in the proceeding direction of the material towards the final end of the roller screen.

Abstract: The invention relates to a process and apparatus for pretreating pulp raw material, to be subsequently prepared in a chemical pulping process, and for preparing cellulose pulp from a fibrous starting material. According to the process the starting material is delignified to yield a chemical cellulose pulp, and the obtained pulp is bleached when desirable. According to the invention the starting material is crushed in cooking liquor prior to delignification in order to open its fiber structure. The apparatus of the invention comprises a frame (21), to which to adjacent first rolls (12; 22, 23) have been fitted, which form a first pair of rolls with the rolls arranged to distance from each other in such a manner that a gap clearance is formed between their outer mantles. The rolls are caused to rotate by a means of power transmission, which causes the raw material to be crushed inside the gap between the rolls where a liquid pocket is formed, from which liquid is absorbed into the fiber material being treated.

Abstract: The invention relates to a dryer apparatus for fiber webs (10), such as webs of natural fiber, synthetic fiber and the like. The apparatus comprises a rotating dryer cylinder (1), the interior of which is provided with elements (8) for injecting hot heat-transfer fluid against the inner cylinder surface and for discharging if from the cylinder interior. The invention relates also to a method for heating a cylinder by injecting hot heat-transfer fluid against the inner surface of the heating cylinder.