Abstract: Glass fibres which are distinguished by their greatly reduced carcinogenicity have an average fibre diameter of <8 .mu.m, preferably <3 .mu.m, with more than 10% of the fibres having a diameter of <3 .mu.m. The types of glass used for producing these fibres are characterized by containing the following compounds in the proportions shown in mol %:______________________________________ SiO.sub.2 55-70 B.sub.2 O.sub.3 0-4 Al.sub.2 O.sub.3 0-1 TiO.sub.2 0-6 Iron oxides 0-2 MgO 0-5 CaO 12-20 Na.sub.2 O 10-20 K.sub.2 O 0-5 fluoride 0-2.

Abstract: A process and device for manufacturing ultrafine fibers and ultrafine-fibre mats from thermoplastic polymers with mean fibre diameters of 0,2-15 .mu.m, preferably 0,5-10 .mu.m, by a melt blowing technique. The polymer melt (12) flows through at least one bore (15) in a melt blowing nozzle (18). Immediately on emerging from the bore, gas is blown against the extrusion from both sides of the bore exit (15), thus breaking up the melt to form fibers. To this end, the gas is accelerated to supersonic speed in Laval nozzles (25, 26; 31, 32), disposed in mirror symmetry round the bore exits (15), and decelerated to just below the speed of sound in channels (27) with constant cross-section, or a cross-section which decreases in the direction of flow, fitted downstream of the Laval nozzles, and the melt (12) fed into the gas stream emerging from the channels (27).

Abstract: The process for the production of mineral wool fibres is based on melt streams 1 issuing from a melt distributor 3 being reduced to fibres in a drawing nozzle 9 by a blast medium flowing with high velocity in the axial direction. The blast medium charged with fibres then arrives in a subsonic diffuser 11 in order to reduce the flow velocity. The fibre-charged stream 10 is subsequently led onwards in a rectangular shaft 13. To separate non-fibrous constituents (so-called shots), a plurality of gas jets 18 are blown in at the shaft end transversely to the main flow direction at an angle .alpha. of 30.degree. to 120.degree.. As a result the fibre-charged stream is deviated. The stream 22 deviated in a direction of .beta.=60.degree. to 140.degree. is then picked up by a fibre shaft 21 mounted at the same angle .beta. and led to a deposition belt 23.

Abstract: The process for the production of superfine polymer fibre novwoven fabrics is based on spinning out radically the molten polymer at supply pressure in a rotating nozzle head (6) through a plurality of discharge opening (27) to form fibres and deflecting in the axial direction the not yet completely solidified fibres at a radial distance of 10 mm to 200 mm from the discharge holes (27) by an outer gas stream (8) and afterwards depositing them as nonwoven fabric (15) on a circulating, air-permeable carrier (12). In addition to the outer gas stream (8) an inner gas stream (24) emerges at a lower velocity from a plurality of axial boreholes (23) in the nozzle head (6) at a smaller radial distance than the discharge holes (27). Owing to the centrifugal sweeping forces at the rotating nozzle head (6) a rotationally symmetrical flow field then developes with a predominantly radial velocity component, the temperature of the gas being equal to or greater than the nozzle head temperature.

Abstract: Fibres, fibre webs or fibre aggregates made of polyphenylene sulphide (PPS) or of mixtures of PPS with other polymers are produced by a melt-spinning process where the melt filaments are drawn out and cooled down to below the melt temperature by a gaseous medium flowing essentially parallel thereto at sonic or supersonic speed, this simultaneous deformation and cooling giving rise to amorphous fine or extremely fine fibres (17) of finite length which are deposited to form a fibre web or fibre aggregate.

Abstract: The polymer granular melt (1) is whirled out of a rotating nozzle head (6) through a plurality of exit holes (24) with fibre formation (32) and the fibres formed (9) are deposited on a collecting surface (12) in web form (15). This polymer melt is introduced into the nozzle head (6) under a preliminary pressure of 1 bar to 200 bar, preferably 1 bar to 50 bar. Furthermore, the fibres (32) are deflected by a high-speed gas stream (7, 8) in a radial direction at a radial distance of 10 mm to 200 mm from the exit holes (24) and, in the course of being deflected, are simultaneously drawn and stretched. The melt streams (32) exiting from the exit holes (24) can be additionally drawn by gas streams (26, 34) exiting in the vicinity of the exit holes (24) at the nozzle head (6) with a predominantly radial component before coming under the influence of the axial deflecting gas stream (7, 8).

Abstract: A method for sealing a passage (2) in a wall (3) for the unsupported transport of continuously accumulating tows (1), in which the pressure difference on both sides of the wall (3) is compensated by an additional gaseous medium (5).

Abstract: Filaments of a molten material issue from a plurality of openings in a heated melt crucible and are further fiberized in a draw nozzle by means of a blowing medium. The diameter of the outlet openings (3) at the base of the melt crucible (1) is very small and is 0.2 to 1.5 mm, so that very fine primary filaments (12) are already formed at this point. These primary filaments are grasped by a very turbulent current at the entrance of the draw nozzle (5). The transverse component of the current decreasing in favor of the longitudinal component as the axial distance from the outlet openings (3) increases. The draw nozzle also has an inlet portion, which has a sharp outer edge and widens in the direction of flow, so that air blows against the primary filaments at a high speed and they are exposed to a strong pressure gradient in the longitudinal direction before entering the inlet portion.