Abstract: Non-flammable, high-temperature resistant polyimide fibers have irregularly lobed or serrated cross-sections, a wool-like smooth hand and high brightness. They are produced by a dry-spinning process which is carried out in a spinning column, wherein a 20 to 40% solution of the polyimide is spun from spinnerets having circular orifices, the orifice numbers ranging from 20 to 800 and the orifice diameters from 100 to 300 .mu.m. An extrusion speed of between 20 and 100 m/min, a take-up speed of between 100 and 800 m/min, an amount of spin gas between 40 and 100 m.sup.3 /h under standard conditions and a spin gas temperature of between 200.degree. and 350.degree. C. are applied. The tows leaving the spinning column, which contain residual solvent from 5 to 25% by weight--based on dry polymer--and have a single filament titer of between 3.

Abstract: A circular loom comprises a machine frame including an upper and a lower running race. Between the running races, a reed and at least one shuttle are arranged. The shuttle is guided in the running races by running rollers arranged on its front and rear ends and is drivable by a catch roller arranged on a rotor. In order to provide an improved shuttle drive that is less susceptible to failures and with which the shuttle will not be pressed out of the running races, the catch roller is in contact with a running roller arranged on the front end of the shuttle during operation and is provided between the running rollers arranged on the front and rear ends of the shuttle.

Abstract: In a circular loom a reed and at least one shuttle are arranged between an upper and a lower running ring of a machine frame. A rotor driving the shuttle, a harness arranged in a concentric circle about the rotor for shedding the warp threads, and tensioning means for the warp threads also are provided. A wave-like extending groove is provided in the outer side of the rotor and catch elements engage therein. The catch elements are connected with flexible bands or cords carrying thread guiding organs arranged at a distance from one another. The bands or cords are deflected at least about upper deflection pulleys, the thread guiding organs coming to lie on opposite sides of the deflection pulley and the upper deflection pulley being at the height of the upper running ring.

Abstract: Methods and apparatus pertaining to reduction of sodium sulfate to sodium sulfide include the feeding of sodium sulfate into a combustion chamber in which the sodium sulfate is exposed to a reducing atmosphere while at the same time being exposed also to a temperature above the melting point of sodium sulfide. Thus, a liquid accumulates at the bottom of the combustion chamber and this liquid will of course contain a considerable amount of sodium sulfide reduced from the sodium sulfate.

Abstract: A method of making threads or fibres of polytetrafluorethylene with improved heat conductibility uses thread of fibre cores enclosed by envelopes which contain fine-particle polytetrafluorethylene, a heat conducting pigment and a binder. Such threads or fibres can be used to form a sealing packing.

Abstract: A method of producing threads and fibers of synthetic materials uses a cylindrically-shaped body of the synthetic material which is allowed to rotate against a scratching tool and a peeling knife arranged to follow the scratching tool in the direction of rotation. The peeled-off curtain of parallel threads is stretched, possibly while being simultaneously heated, and possibly the threads are cut to form a staple fiber or are ground to a short-staple floccule. A device for carrying out the afore-mentioned method, has a turning mechanism, a foil-peeling knife secured to a carriage of the turning mechanism, and a scratching tool arranged to precede the peeling knife.

Abstract: Manufacture of flame-retardant regenerated cellulose fibres by adding one or more flame-retardant phosphorus comounds to viscose, extruding the viscose-containing mixture thus obtained into a spinning bath, stretching and after treating the resulting filaments or staple fibres. The flame-retardant fibres are made by using as the flame-retardant agent a combination of compounds of the general formula:PN.sub.x O.sub.yin which x stands for a number between 0.09 and 1.7 and y stands for a number between 1.2 and 0, preferably approaching zero as the values of x increase towards 1.

Abstract: Flame-retardant fibers of regenerated cellulose are produced by adding one or more flame-retardant phosphorus compounds to the viscose, extruding the viscose into a spinning bath and, if desired, stretching and after-treating the resulting filaments or staple fibers. The flame-retardant agent is a compound of the general formulaPN.sub.x O.sub.yin which x stands for a number between 0.9 and 1.7 and y stands for a number between 1.2 and 0, where the y-values converge towards zero as the x-values increase. The flame-retardant agent is more particularly used in a proportion approximately between 5 and 30 weight %, based on the weight of the cellulose.