Method and apparatus for spinning and crimping a synthetic multifilament yarn

Abstract

A method and an apparatus for spinning and crimping a synthetic multifilament yarn, wherein a filament bundle is spun from a polymer melt and compressed to a yarn plug. The yarn plug is advanced at a cooling speed and cooled within a cooling zone in a moving cooling groove. After cooling, the yarn plug is disentangled to form a crimped yarn, with the latter being wound to a package. The method of the invention also provides for selecting the length of the cooling zone and the cooling speed of the yarn plug such that the yarn plug is cooled in the cooling groove over a period of at least 1 second. To this end, the apparatus of the invention includes a cooling groove, whose width is dimensioned such that the yarn plug can be advanced in meander form in a plurality of superposed layers.

1 . A method for spinning and crimping a synthetic multifilament yarn, comprising the steps of
 spinning at least one filament bundle from a polymeric melt and compressing the bundle to a yarn plug,   cooling the yarn plug by advancing the plug at a cooling speed through a cooling zone which comprises a moving cooling groove,   disentangling the yarn plug after cooling to form a crimped yarn which is wound to a package, and   wherein the length of the cooling zone and the cooling speed of the yarn plug are in proportion with respect to each other and so that the yarn plug is cooled in the cooling groove over a time period of at least one second.   
     
     
         2 . The method of  claim 1 , wherein the yarn plug is cooled in the cooling groove over a period of at least two seconds. 
     
     
         3 . The method of  claim 1 , wherein before being cooled, the yarn plug advances at a yarn advancing speed, and while being cooled at the cooling speed, with the cooling speed being lower than the yarn advancing speed. 
     
     
         4 . The method of  claim 3 , wherein the yarn advancing speed of the yarn plug is at least twice as high as the cooling speed of the yarn plug. 
     
     
         5 . The method of  claim 1 , wherein at the beginning of the cooling zone the yarn plug is laid in the cooling groove in meander form. 
     
     
         6 . The method of  claim 5 , wherein the yarn plug advances in the cooling groove on the circumference of a rotatably driven cooling drum, with the bottom of the cooling groove forming an air permeable cooling surface. 
     
     
         7 . The method of  claim 1 , wherein the yarn plug is cooled within the cooling zone by a cooling medium flow. 
     
     
         8 . The method of  claim 7 , wherein the cooling medium flow is generated by a source of vacuum and/or a source of overpressure.