Abstract: A method and a d.c. arc furnace for thermal treatment of an ash, wherein reducing conditions are established within a closed and sealed furnace, the ash is supplied via a channel arranged in an electrode which extends towards a metal melt in a furnace shell and provides an arc extending toward the metal melt, the ash being fed from the open free end of the electrode through the arc, any slag and/or the metal melt, whereby the ash is rapidly heated under reducing conditions to a temperature of 1350.degree. C. to 1750.degree. C.

Abstract: The invention relates to an arrangement in cylinder drying, intended for incorporation in a paper machine and including a plurality of heated cylinders (1) arranged substantially parallel in two rows, about which the paper web (2) is taken serpentine during drying, whereat it is carried by an endless porous fourdrinier wire (3) which presses the web against the cylinder surfaces in one row of cylinders and lies between the paper web and the cylinders in the other row. For preventing the web from lifting from the wire as a result of pressure differences on either side thereof, there are blowing boxes (11,12) arranged for blowing out air in at least some of the pockets (4,5) situated on opposite sides of the web, each of said pockets being formed by the web and three cylinders lying consecutively in the travelling direction of the web.

Abstract: The invention relates to a plant for drying a material web. Such plant includes a plurality of upper (3) and lower blow boxes arranged substantially mutually parallel and at right angles to the travelling direction of the web. The lower boxes are intended to support the web and are provided in their surfaces facing towards the web with orifices for blowing air in directions substantially parallel to the plane of the web. The air ejection velocity is thereby sufficient to maintain the web in a specified floating position above said boxes. The upper blow boxes (3) are situated on the other side of the material web and have orifices for blowing air substantially perpendicularly to the plane of the web. According to the invention, the distance (H) between the blowing orifices of the upper blow boxes and the web is variable. It is furthermore adjustable so that the relative energy requirement for the upper blow boxes may be brought closely into the region of the value 1.

Abstract: A cylinder dryer usually includes a plurality of heated cylinders (4) about which a web-like material (1) is taken in a zig-zag mode and pressed against certain of the heated cylinder surfaces by means of an endless high-permeability wire (3), whereby cylinder pockets are formed between the cylinders (4), web (1) and wire (3), when the latter relinquishes contact with the web at a cylinder surface (6) to pass over a return roll (7) arranged between the cylinders, and once again makes contact with the web at the next following cylinder circumference (8). According to the invention these cylinder pockets are ventilated by a flow of drying air from a blowing box (9) being blown over the width of the wire against its surface facing away from the cylinder, in a direction forming an acute angle to and having a directing component substantially counter to the direction of travel of the wire. Blowing is carried out thereby within an area (6) where the wire relinquishes contact with the web.

Abstract: A treatment plant for web material which, when bent, exhibits stiffness transverse to the direction of bending. The treatment plant comprises a series of blow boxes arranged in sections with the boxes in each section having parallel plane perforated surfaces on opposite sides of the web path. The perforations are graduated in degree with a high degree of perforation on one side of the web path being opposed by a low degree of perforation on the other side of the web path, and vice versa, so that the web assumes a wave shape between the first and second planes, the wave staying with its nodes in definite positions closer to the one plane opposite the highly perforated group in the second plane and closer to the second plane opposite the highly perforated group in the one plane.