Abstract: An apparatus for producing fibrous sheet material comprises a slot nozzle having side walls normal to converging frontal walls, its inlet opening communicating with means for dispersing fibers in a gas stream, while its outlet opening communicates with a chamber. A flat screen adapted to form a fibrous layer thereon is mounted under the chamber, and a suction box is arranged underneath the flat screen, wherein the side walls of the slot nozzle are parallel with respect to each other, and means for removing part of the gas from the gas-fiber stream are provided in the chamber under the outlet opening of the slot nozzle, the chamber being provided with branch pipes for gas exhaust, mounted substantially in the upper portion of the chamber.

Abstract: A method for producing fibrous sheet material comprising dispersing fibers in a gas stream to obtain a gas-fiber stream, supplying the gas-fiber stream onto a flat screen, removing gas from the gas-fiber stream through said screen to form a fibrous layer thereon, removing part of the gas from the gas-fiber stream prior to supplying it onto the flat screen, simultaneously damping transversal pulsations induced in the gas-fiber stream during the course of its movement. The fiber concentration is increased to 20-500 g/m.sup.3. The fiber concentration is chosen in accordance with the specific fiber and its properties. An apparatus for carrying out this method comprises a slot nozzle having side walls normal to converging frontal walls, its inlet opening communicating with means for dispersing fibers in a gas stream, while its outlet opening communicates with a chamber.

Abstract: A distinguishing feature of the method lies in that the moist fibrous raw material is constituted by a suspension of a fibrous material with a fibre concentration of 5-30 wt. %; said suspension is heated before dispersion to 102.degree.-145.degree. under a pressure of 1.1-4.0 atm abs and fed in the form of a stream into a moulding chamber where pressure in the stream is sharply reduced to 0.8-1.0 atm abs in the course of 10.sup.-1 -10.sup.-3 seconds.