INTRODUCTION

A jigger is composed of a trapezoidal tub containing the bath and two rolls on which the fabric is alternatively wound. In this type of machine the bath is stationary while the fabric is in motion. The fabric, initially wound on the first roll, flows through the bath and then is wound on the other one; the rotation is then reversed and the cycle continues. The fabric is led in its path by a few small guide rollers.
HT jiggers are also produced, allowing treatments at temperatures above 100 °C. This type of machine is used not only for dyeing, but also for various wet treatments on fabrics in full width.
The main disadvantage of this system is the risk of non-homogeneity between the initial and final part of the roll. This is due to variations in feed speed and tension of the fabric, or temperature and chemicals concentration in the bath during the period of the treatment. However, in modern jiggers tension of the fabric is kept constant during the whole process, thanks to special devices.