Dyed Yarn Drying Process | Drying Mechanism of Stray-field FASTRAN Textile Dryer

Dryer is essential to remove remaining water from the package. About 60-80% water removes by dryer. After passing Hydro section package move into drying section. Following is most used yarn dryer use in yarn dyeing industry.

  1. Stray-field FASTRAN Machine
  2. GALVANIN (Hot Air Dryer)

Drying Mechanism of Stray-field FASTRAN Textile Dryer: There are lots of dyed yarn dryer for drying the dyed yarn which passed hydro-extractor. I have written about the drying mechanism of Stray-field FASTRAN Textile Dryer.

Direct method of heating are those where the heat is generated within the material itself with ratio frequency and microwave method being typical examples. This method of heating is also referred to as dielectric heating.

Most non-metallic substances undergo a uniform rise in temperature when subjected to a high frequency electric magnetic field. Each time the direction of the applied RF field reverse, so the polarization of the individual molecules within the substance changes. The constant molecular movement causes friction which in turn leads to a rise in temperature. As may be expected the higher the frequency of the electromagnetic field the faster the molecules process, thus creating more friction and consequently more heat is produced.

The frequency of the RF fields generated by devices for dielectric heating is centered on 13.50 MHZ and 27.12 MHZ.

Here, I like give a simple idea about the Stray-field FASTRAN Textile Dryer.

Brand Name                : Stray-field

Country Origin             : UK

Supply Voltage            : 380-420

Supply Frequency        : 50 HZ

Supply Phases             : 3

Supply KVA                 : 230

Supply Power Factor    : 0.9

Maximum Weight         : 3800 Kg

RF Power Output         : 100 kW

Operating Frequency    : 27 MHZ

Points Need to Consider During Drying: Following points are need to consider during yarn drying. They are:

  1. Machine Speed: Machine speed varies according to the shade of the yarn. Conveyor runs in high speed for dark shade and comparatively at low speed for light shade.
  2. Feeding System: Plastic package feed in vertical form, but spring package feed in horizontal form because fire can be form by feeding in vertical form.
  3. Yarn Type: Same type yarn should run at same settings. Otherwise it can damage the yarn quality. Cotton, Polyester, Acrylic, P/C or CVC yarn should feed separately.
  4. Moisture: Machine settings should be according to the amount of moisture remain in the package.

Evaluation of Efficiency of Stray-field Dryer: It needs to know the efficiency of a dyed yarn dryer. For this reason, I have presented a sample calculation of dyed yarn dryer efficiency.

Weight of double yarn package before dyeing               =  1.2 Kg

Weight of double yarn package with water before Dryer = 2.034 Kg

Weight of water in double yarn package before Dryer = (2.034 – 1.2) Kg =  0.834 Kg

Weight of package after Dryer          =          1.2 Kg

Water remain in package after Dryer   =          (1.2 – 1.2) Kg =  0 Kg

Water remove by Dryer                     =          (0.834 – 0) Kg = 0.834kg


=   {(Weight of water before Dryer – Water remain after Dryer) / Weight of water before Dryer}   X 100%

=   {(0.834 – 0) / 0.834} X 100%

=    1 X 100%

=    100 %

Efficiency of Dryer = 100 %

So, yarn dryer is essential for dry the dyed yarn. After drying, dyed yarns transferred for re-winding or random section.

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