Winch Dyeing  machine


This machine is normally used for dyeing of delicate fabrics ten or lightweight cotton fabrics like voiles and crepes as well as knitted fabrics and silk and rayon fabric generally in rope form. the fabric can by dyed in open width also. In winch  is also referred to as "loose dyeing", the fabric. is subjected considerably less tension as compared to jigger dyeing where it subjected to warp tension which some fabrics are unable to withstand without damage. Further, the m:1 ratio in winch dyeing is so high that the material practically floats in the dye-liquor and remains immersed in it for quite some time. The machine consists of an elliptical or circular winch. which extends over the full width of the dyebeck and is power driven. Some machines have provision to reverse the direction of speed and are designed 

                                   winch machine
to give constant speed of cloth. The machine has a perforated portion in the front for adding dye solution and for heating it and h by steam pipe. The dye vat is rectangular or V shaped. The machine used for silk and rayon fabrics has a rectangular vat shallower than that used for cotton fabrics. In working this machine, one end of the fabric is run over a guide roller and passed between the pegs over the winch and the other end of the fabric is stitched together to form a rope or a continuous loop with a considerable amount of slack' which permits immersion of the fabric in the liquor for an ample period. Many such ropes run together separately by a series of pegs into a dye-liquor over the winch. The ropes are drawn in and out of the dye-bath by the rotating winch. During dyeing, the ropes of fabric pile down in the dye-liquor where they remain immersed for sometime until they are drawn out again by the winch. At the end of dyning, the machine is stopped and the pieces separated. They are then plaited on a draining board and removed

The older type of machines were made of wood or iron but now they are made of stainless steel or monel metal; they are easy  to clean and are smooth so that there is little friction. Totally enclosed winch machines have been developed to permit better and uniform peretration of the liquor and effect economy in consumption of steam winch machine are working in high pressure and high temperature have also developed


Disadvantages of Winch Dyeing


1   
Because of the high m:l ratio required in dyeing, the consumption of water, steam and chemicals is high. Where the dye is taken on the basis of liquor as in the case of naphthols, the dye consumption is also high

2   As the fabric is irregularly piled in the liquor, uneven dyeing can take place; lower speed can also lead to uneven dyeing

 In open winches, the temperature may vary in different parts and even though the temperature of liquor in the vat is at boiling point, the fabric loses its heat during passage in the air

4  Only a small lot of fabric can be dyed at a time.



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