GB1299944A - Method and apparatus for producing a bulked yarn - Google Patents

Abstract

1299944 Crimped yarn FIBER INDUSTRIES Inc 6 Aug 1970 [8 Aug 1969 (2)] 37939/ 70 Heading D1F A process for producing a crimped yarn having latent bulking characteristics comprises feeding a drawn pretensioned multifilament yarn to a crimping zone crimping the yarn, withdrawing the crimped yarn under constant tension not exceeding 0.1 gm/dernier and constant speed, cooling the yarn, increasing the tension to a constant tension between 0.03 and 0.8 gm/denier, and compacting the yarn to facilitate further processing. Apparatus for carrying out the process is characterised in that the drawing means comprises a feed roll 16, a draw roll 20 and a draw pin 18 therebetween, the crimping means 24 being positioned to receive the drawn yarn with the minimum delay; the yarn tensioning means comprises a braked roll 28, a withdrawal roll 34 and a tension leveller, e.g. swinging arm 32 therebetween. The crimping means is preferably a stuffer box comprising an elongate chamber and feed means, e.g. rolls 22 for the chamber, the chamber having a compaction area and a fibre exit area. The compaction area comprises opposed guide means in the plane of the feed means and fibre confining means in a plane at an angle of 45-135 degrees to the plane of the feed means. The fibre exit area comprises diverging confining means and corresponding converging fibre back-pressure producing means, the diverging and converging means co-acting to translate fibre frictional force from the plane of the feed means to the plane of the backpressure means. The confining means preferably comprise a pair of opposing doctor blades, which provide a primary divergence in the compaction area and a secondary greater divergence in the exit area. The back-pressure producing means is preferably in the form of a stabilizer mounted in a plane at right angles to the confining means and is adjustable to vary to amount of back-pressure. The apparatus preferably includes cooling means 26 which also serves to pretension the yarn leaving the crimper. The cooling means is preferably in the form of a quenching jet the air jet being directed against the running yarn. The jet comprises a pair of spaced opposing walls each containing a plenum chamber with a gas exit port, which ports are directed into the space between the walls. The quenching jet may also effect an intermingling of the filaments of the yarn. The tensioning means 28, 34, effects a temporary, straightening of the crimps and the braked roll 28 may be in the form of a frictionally impeded channelled wheel, a fluid clutch, a magnetic particle clutch or an eddy current brake. The crimping means is preferably a stufferbox crimper but may be a steam jet or gear crimper. The compacting means may be a conventional twister or an air entanglement jet or adhesive applying means. The process is preferably carried out on polyamide yarn and produces a uniform yarn.