All the techniques discussed in the previous sections depend up on dissolving the dye stuff in water.
Recent techniques have used other liquids, such as ammonia, perchlorethylene and dichlorobenzene, which have been found to be superior dye vehicles.
These liquids are better dye solvents and they penetrate better a wide variety of manmade fibres.
Furthermore, there is a saving of energy and its cost.
The exhausted solvents are reconvert able and there by non polluting and there are a less expensive means of dyeing.
To improve the dye penetration, a machine called the pulsar was invented in Italy. The machine utilizes sets of continuous rapid impulses in the solvent medium that hits both sides of the fabric in rythematic alterations.
The material is moved by gravity and vibration of the pulsators.
Tension, stretch and surface distortions are eliminated.
Conveyor belts carry the fabric to the suction dryer.
Both open width and tubular fabrics can be dyed by this method.
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