A New Concept in Cooler Design for False-Twist Texturing Systems

Abstract

In false twist texturing, yarns are bulked by the sequential operations of twisting, heating, and cooling. The current speed for false twist texturing is limited by the early onset of threadline instability. It is well known that there is a potential to increase speeds by reducing the length of each element of the process. This paper describes the develop ment of a short-length water cooler that operates by direct contact between water and yarn. The important design parameters are identified and optimized, and the predicted perfor mance is in agreement with simple transient heat transfer theory. Trials have shown that commercially acceptable 167 decitex yarns can be produced with continuous running at 1000 m/min and with a potential speed of 1700 m/min or more.

A Review on False-Twist Texturing

“…The temperature must be distributed well along the cross-sectional area of the yarn after leaving the heater, because otherwise, inhomogeneous temperature distributions can lead to inhomogeneous crystallisation behaviour, which, in turn, leads to a worse dyeability in later processing steps. This is a crucial factor in textured yarns, as the human eye can easily spot inconsistencies in colour fastness in later-produced fabrics [17,[22][23][24]. Furthermore, simple and effective temperature control systems, as well as reliable and economical operation, are necessary [25].…”

“…Different plastics, like polyester and nylon, have different cooling requirements due to their behaviour around the glass transition temperature T g . However, they all need to be cooled below their specific T g before entering the twisting unit [1,22]. The glass transition temperature describes the transition of the yarn from a rubbery to amorphous state [1].…”

“…Another actively used solution is to cool the yarn using active cooling with water as a coolant. The yarn passes through a water bath in which the circulating water is kept at a constant temperature [1,22]. The cooling device is designed with a pressurised air labyrinth system at both ends, which ensures that no water escapes [1,18].…”

A Review on False-Twist Texturing

“…This is a crucial factor in textured yarns, as the human eye can easily spot inconsistencies in the colour fastness in later produced fabrics. [17,[22][23][24] Furthermore, simple and effective temperature control systems as well as reliable and economical operation are necessary [25]. This is a crucial factor in textured yarns, as the human eye can easily spot inconsistencies in the colour fastness in later produced fabrics.…”

“…This is a crucial factor in textured yarns, as the human eye can easily spot inconsistencies in the colour fastness in later produced fabrics. [17,[22][23][24] Furthermore, simple and effective temperature control systems as well as reliable and economical operation are necessary.…”