Wednesday, January 13, 2010

Jet Dyeing

Jet Dyeing Machine
A machine used for dyeing of fabric in rope form.Jet dyeing machines came into existence with a purpose to minimise or eliminate the drawbacks of earlier machines like winch , jigger and beam dyeing units.
Principle of the Technology
Jet dyeing is a process that can be used for batch dyeing operations such as dyeing, bleaching, washing and rinsing. In this process, dyeing is accomplished in a closed tubular system, basically composed of an impeller pump and a shallow dye bath. The fabric to be dyed is loosely collapsed in a form of a rope, and tied into a loop. The impeller pump supplies a jet of dye solution, propelled by water and/or air, whch transport the fabric within the dyeing system ,surrounded by dye liquor , under optimum conditions. Turbulence created by the jet aids in dye penetration and prevents the fabric from touching the walls of the tube, thus minimizing mechanical impact on the fabric.

see video jet dyeing machine 

Special Features and Applications
1.Jet dyeing machines can be operated even at high temperatures and pressures. Jet dyeing systems are fitted with cooling systems with the potential for reuse of the warmed water on the next dyeing cycle.
2.Jet dyeing systems operate at a low liquor ratio, or the ratio of the mass of the dye bath to the mass of the fabric in the dyeing machine. Compared to conventional dyeing, typically with a liquor ratio of 1:15 to 1:25, jet dyeing can be operated at a liquor ratio from as low as 1:3 up to 1:6. Consequently, the dyeing operation consumes less water and chemicals, and generates less effluent.
3.Since the dyeing process depends on dye concentration, the lower liquor ratio increases the dyeing rate and dye fixation.
4.Increased dyeing rate results to quicker machine drains and fills, and more rapid heating and cooling. The latter decreases energy requirements for heating the dye bath, which then leads to reduced steam and boiler use, reduced fuel consumption, and fewer emissions to the atmosphere from combustion.
5.The lengthwise tension is less , widthwise tension is absent and fabric achieves better fullness and handle.
6.The frequent movement of fabric round the jet through the machine reduces the tenedncy of crease formation.
Limitations of Jet Dyeing machines
1.High Initial investments and maintenance cost.
2.Limited accessibility during the dyeing process.
3.Foam forming substances are to be avoided.
4.Any roughness of the  inside surface cause damage to cloth.
5.In case of cloth breakage , rethreading is complicated.
Types of Jet Dyeing Machines
After incestifating the dyeing results under different conditions such as development of new fiber blends , different construction fabrics,interaction position of jet,quantity of the dyeliquor to be  present in around the fabric and the type of impact of the dyeliquor on the fabric in the jet area, the following type of jet dyeing machines were developed,
1.Fully flooded jet dyeing machines click here
2.Soft flow Jet dyeing machines Click here for details
3.Low liqour ratio . reel jet dyeing machines. Click here for details .

Watch animated working principle  of jet dyeing  machine.

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