Abstract: A blowbox for use in a plant for drying a material web includes an essentially horizontal box wall having formed therein circular orifices and eyelid perforations each of which includes a slit extending in parallel with the center line of the upper box wall. A depression is formed m the upper box wall adjacent one side of the slit. The eyelid perforations are arranged in two rows and parallel with the center line and together they form a zigzag pattern about the center line that intersects the depressions of the eyelid perforations in both rows. The orifices are disposed in a first and second pair of rows with both rows in each pair positioned on either side of and spaced equally from the center line. The upper box wall has a shallow continuous arcuate shape across its entire width.

Abstract: A cyclone for treating a gas flow (F) containing dust comprises a cyclone chamber (1) of circular cross section and having a vertical axis, and a central tube (7) of circular cross section, which is coaxially arranged in the upper portion of the cyclone chamber (1). An elongated insert element (10), which is vertically inserted in the central tube (7), is so designed and extends in such a manner downwards in the central tube (7) from the upper end thereof that a circumferential gap (17) exists between the insert element (10) and the central tube (7). This gap (17) has a preferably constant cross-sectional area which does not increase in the direction of the gas flow.

Abstract: A device is arranged in the drying section of a papermaking machine for reducing the effects of the tendency of a paper web (4) to adhere to a drying cylinder (1) as it passes from the drying cylinder to a subsequent guide roll (2). In the drying section, the paper web (4), supported by a drying fabric (5), is conducted alternatingly over a plurality of drying cylinders (1) and guide rolls (2). A blow box (6) is arranged in the transition portion (A) and has a wall (7) extending in parallel with the drying fabric (5) so as to form a narrow air gap (8) between the wall and the drying fabric. The blow box (6) comprises nozzle (12) having a slot-shaped opening for ejecting a well-defined air jet (P1) towards the drying fabric (5) away from the air gap (8). The nozzle (12) is directed such that its center plane intersects the circumferential surface of the drying cylinder (1) along a first straight line positioned upstream of a second line, along which the paper web (4) leaves the drying cylinder (1).

Abstract: In a method for cleaning polluted gas and/or cooling of hot gas, and a device for carrying out the method, the gas is contacted with finely divided liquid. The finely divided liquid is supplied in the form of essentially umbrella-shaped shells or essentially linear curtains, in a regular arrangement, distributed in two or more planes substantially perpendicular to the main flow direction of the gas. The finely divided liquid is supplied such that the gas is alternatively concentrated and spread by the impulse action exerted by the liquid on the gas in directions perpendicular to the main flow direction of the gas. The orthogonal distance between adjacent planes in which finely divided liquid is supplied, is so adjusted that no substantial equalization of the gas flow takes place between the planes.