Abstract: A device for colorimetric analysis of samples comprises a plurality of groups of receptacles, means for bringing these groups successively to a testing station, and means for automatically performing a cycle of analysis on the receptacles of the group at that station. The analysis means includes a light source, a photodetector aligned therewith, and a plurality of filters. The receptacles of each group and respective filters are moved successively into alignment with the source and detector so that the contents of each receptacle are analyzed with the aid of the correct corresponding filter.

Abstract: Cleaning device for spinning units. According to the invention, the device is placed on a carriage movable along a set of spinning units. The device comprises a pressure fluid supply and a suction supply carried by the carriage. The pressure fluid supply is selectively connectable to a blowing nozzle opening internally of the chamber of each of the spinning units, whereas the suction supply is selectively connectable with a suction duct opening in the spinning chamber and containing a check valve, the opening of which is controlled by the depression or vacuum built up by the suction supply.

Abstract: Cleaning device for open-end spinning unit, the device comprising a pivoted housing for a rotor, having a cover hinged to a frame. The device comprises means to stop cover movement to an angular position in which the axis of a telescopic tube mounted on the cover and connectable to a fluid pressure source, passes by the fiber collecting surface of the rotor. The tube end is provided with a baffle for directing fluid tangentially to the rotor and a curtain provided for sealing the space between the cover and the housing in their open condition.

Abstract: A device for reinserting the broken yarn in an open end spinning unit, comprising a yarn gripping element, attached to an endless belt passing in front of a yarn gripping position on the winding up bobbin and a device for reinserting the broken yarn in the spinning unit; control means act on the belt to move the yarn gripping member from the gripping position to the reinserting position in the spinning unit and then stopping it at least at a location of the path of the endless belt.

Abstract: A weft-knitting apparatus is provided with an axially nondisplaceable but rotatable loop-forming element having an upper end cut off at an oblique angle and formed with a spur. Each loop-forming element is periodically rotated 360.degree. so as to pick up a filament with its spur to pull it through a loop previously formed, thereby forming another loop that can thereafter slip up over another loop so formed by the spur. The support carrying a plurality of such rotatable elements may be exchanged for another such support having elements differently spaced in order to use the same knitting machine for different gauges or cuts.