Abstract: The disclosure relates to a method for operating a system that includes at least one suction device and at least one hand-held power tool. The method includes establishing a communications link between the suction device and the hand-held power tool by means of at least one suction device communication unit and at least one hand-held power tool communication unit, and transmitting at least one communication signal by means of the communications link from the hand-held power tool, in particular the hand-held power tool communication unit, to the suction device, in particular the suction device communication unit. When the suction device is switched on, at least one start signal is sent to the hand-held power tool, the hand-held power tool being activatable only if the start signal is received by the hand-held power tool.

Abstract: The disclosure relates to a method for operating a system that includes at least one suction device and at least one hand-held power tool. The method includes establishing a communications link between the suction device and the hand-held power tool by means of at least one suction device communication unit and at least one hand-held power tool communication unit, and transmitting at least one communication signal by means of the communications link from the hand-held power tool, in particular the hand-held power tool communication unit, to the suction device, in particular the suction device communication unit. When the suction device is switched on, at least one start signal is sent to the hand-held power tool, the hand-held power tool being activatable only if the start signal is received by the hand-held power tool.

Abstract: In an improved crimping process, use is made of a stufferbox where(a) lid and/or floor are arranged movably and(b) in the working position, the distance between lid and floor at the inlet opening is smaller than the distance between lid and floor at the outlet opening.

Abstract: Extraordinarily low ranges of error, with respect to yarn adhesion and uniformity, in dry spinning yarns are achieved when the spinning gas in the upper part of the shaft blasts the yarns radially from the inside to the outside in an apparatus designed for this purpose, the velocity of the radial flow of gas, dirctly below the spinning nozzle, transverse to the running direction of the yarns and within a spacing of 10 mm from the nozzle, increasing from 0 to at least from 0.2 to 1 m/s.

Abstract: High-strength filaments of dry-spun polyacrylonitrile are obtained by a process in which tension-reduced spun filaments are continuously stretched hydrothermally in one or more stages: where it involves several stages, stretching is carried out at a temperature of the stretching medium gradually increasing from stage to stage up to .theta.=.theta..sub.n and, in the final (n-th) stage, to a degree of at least 50% of the maximum degree of stretching; where it is carried out in a single stage, stretching is carried out at the optimal stretching temperature .theta..sub.n, after which the material is further treated in the conventional way, optionally with fixing of the stretched material to a pre-determined extent.

Abstract: The recovery of dimethylacylamides from solutions which are formed during the production of fibres is particularly economical if the solution is concentrated in a separating column to produce a sump product having a DMA content of 30 to 90% at pressures of more than 300 Torr, using the evaporation heat of the head product for heating the column, with the aid of a compressor and then separating the sump product which is concentrated in DMA by distillation.

Abstract: The invention relates to a bi-component filament or fibre of a fibre-forming synthetic polymer having a core/sheath structure in at least one component and having a moisture absorption of at least 1.5% at 65% relative atmospheric humidity and at a temperature of 21.degree. C. and a moisture absorption of at least 5% at 90% relative atmospheric humidity and 21.degree. C. and a water-retention-power of at least 10% as well as to a process for the production thereof.

Abstract: The invention relates to a process for the production of bifilar fibres and filaments consisting of only one acrylonitrile polymer. The polymer is dissolved in a usual solvent and the resulting solution is divided up into two solution streams. After these solution streams have been brought to different temperatures they are spun by a conventional bifilar spinning technique.

Abstract: The invention relates to a process for continuously removing residual solvent from filaments of dry-spun acrylonitrile polymers to values of below 2% by weight of solvent by a multi-stage hot-wash with low quantities of water.