HANK DYEING MACHINE

   
    Hank dyeing consists of immersing large, loosely wound hanks of yarn into dye vats that are especially designed for this purpose soft, lofty yarns, such as hand knitted yarns are usually skein dyed.

 Roller Hank Dyeing Machine

   These machines are based on Hussong type of hank dyeing machines in design. These machines are very simple in design and operation.

   In the basic design of machine there is rectangular stainless steel tank with proper heating mechanism and have a false bottom above the heating coil.

   The tank is fitted with a temperature indicator and control sensor. There is an array of stainless steel rollers which are fitted on a suitable frame. The rollers can rotate in clock wise or anti clock wise directions with gear arrangement. The machine is fitted with stop/start system to control the roller movement. The hanks loaded on rollers can be lowered in the tank or lifted out by lifting or lowering the frame with the help of hydraulic system.

   Working of the machine :

    The hanks to be dyed are loaded onto the rollers bars by avoiding overlapping of hank, in lifted position. The dye bath is kept ready with proper liquor level and mixed homogeneously, preferably with an external circulation pump. The hanks are lowered into the dye bath and movement is started approximately 40-50% part of the hank remain the liquor and rest is exposed to atmosphere.

    The material is lifted up for addition of colors, chemicals, slat, alkali etc or for raising the temperature of dye bath. In case of in direct heating the dye bath temperature may be increased at set rate of heating, but in case of direct heating the temperature rise is step by step. The sample may be drawn at the completion of dye cycle and checked for shade, without stopping the machine. All operations can be done in the same machine.

   Advantages :

• It is simple in design and operation.
• Cost of the machine is not very high.
• All types of yarns can be processed such as cotton,mercerized cotton, viscose filament or even silk can be processed.

    Disadvantages :

• Only limited automation is possible
• Only 40-50% of yarn takes part in dyeing and rest is exposed to atmosphere, therefore hydro sulfite consumption is high in these machines.
• The liquor ratio increases with heating in case of direct injection of steam.