Abstract: In an unraveling facility according to the blast drawing process a subsonic diffuser (11) is arranged following the blast pipe (6). The subsonic diffuser (11) is designed as a thrust diffuser with a sudden cross-sectional widening of its flow border in order to form several stages (13, 14, 15). In this way, a larger median expansion angle (.alpha.) can be chosen without risking detrimental detachment of the main flow than is possible with subsonic diffusers having a continuous flow border. Furthermore, the whirls formed under setoff levels prevent the fiber parts from coming into direct contact with the walls, so that a considerably reduced bead content results in combination with the strong flow expansion and ensuing reduction of mutual contact and penetration of fiber parts. The diameter distribution of the fibers is smoothed out, since speed distribution, which exhibits strong border stress when it emerges from the drawing gap (8), is smoothed out quicker due to the energy consumed by the whirls.

Abstract: A process of melting silicate raw materials includes the steps of using the tank exhaust gases to heat the combustion air, using the tank exhaust gases to preheat a mixture of raw materials, removing acid gaseous aggressive media from the tank exhaust gases, then using the tank exhaust gases to preheat the combination air. Because the acid gaseous aggressive media are removed from the tank exhaust gases before the tank exhaust gases are used to preheat the combustion air, more heat can be withdrawn from the tank exhaust gases than was heretofore possible, since there is no danger of acid condensation even when the tank exhaust gases are cooled to near ambient temperature.

Abstract: Apparatus for producing mineral fibres from silicate raw materials such as basalt by blast drawing.When blast drawing is used to produce mineral fibres from basalt, there is arranged between the entry zone (26) of the chute (16) and the exit zone of the nozzle slot (10) of the blast nozzle unit (8), this slot forming the fiberization duct, a guide cell (13). The relative position of the side walls (29) of the guide cell is freely adjustable, so that desired flow conditions can be set and also the exit direction of the exit flow bundle (31) and hence the web formation can be controlled. As a consequence of a lateral distance (a) of the exit orifice (28) of the guide cell (13) relative to the entry flow bundle (27) additional secondary air is sucked in, which has a further cooling effect on the fibres.

Abstract: To produce basalt wool having a large fibre diameter of if desired 10 .mu.m with high output and low bead formation, the exit cross-section of the exit orifices (6) of the distributor tank (5), the vertical distance (vA) between the exit orifices (6) and the blow-in slits (29) for propellant gas, the horizontal width (hB) of the nozzle slot (10) and the vertical length (vL) of the nozzle slot (10) downstream of the blow-in slits (29) are dimensioned to be unusually large for an apparatus for producing rock fibres by blast drawing. As a result, it is possible to operate at a low melt temperature and a high propellant gas rate combined with a low propellant gas pressure in order, surprisingly, to obtain a coarse-fibered product with low bead formation and high output.

Abstract: Technique for making exhaust muffler lining comprising mineral fibers with metal fibers distributed therein toward the inner surface of the lining, the metal fibers being bound by the fiber binder carried by the mineral fibers.