YARN DYEING INDUSTRY
OPTIMUM PACKAGE WEIGHT IN YARN DYEING
OPTIMUM PACKAGE WEIGHT FOR COTTON AND POLYESTER PACKAGES PRESENTED BY SSM DYEPACKAGES/ REWINDING DOWNLOADED FREELY FROM www.ssm.ch/download.php?ID=579
RANDOM VOLUME WEIGHT DENSITY DYEING CAPACITY
PRECISION OR DIGICONE RANDOM 3390cm3 1120gms 330 gms/lit 100%
PRECISION 3390cm3 1425gms 420gms / lit 127% Gain
Mark The Density of the Package : 420 gms per litre. We read in Part I of this study that packages have inherent density variation from 2.2% to 4.9% within and between packages. SSM recommends in the same article that packages be compressed upto 10% to neutralize the density variation. The Optimum Density of Dyeing of Cotton Yarns : 396 gpl Final Density after compression should not exceed: 396 gpl Density Before compression : 396 x 0.90 = 356.4 gpl In order to get the density of 356 gms per litre, let us see, what will be the final package weight on Soft Winder
PARTICULARS CONICITY
TO FIND DENSITY, FOR A PARTICULAR WEIGHT 0 DEG 0 MIN
EMPTY CHEESE OD IN MM
63
FULL CHEESE OD IN MM
180
TRAVERSE LENGTH IN MM
152
VOLUME IN CC
3.395,47
NET WEIGHT IN GRAMS.
1200
DENSITY IN GMS/C.C.
0,353
PRECISION WOUND OPTIMUM DYE PACKAGE WEIGHT FOR COTTON YARNS : 1.2 KGS DENSITY BEFORE COMPRESSION : 360 gms per litre DENSITY AFTER COMPRESSION : 396 gms per litre RANDOM WOUND OPTIMUM DYE PACKAGE WEIGHT FOR COTTON YARNS : 1.1KGS DENSITY BEFORE COMPRESSION : 330 gms per litre DENSITY AFTER COMPRESSION ( 18%) : 390 gms per litre
CONCLUSION THE WEIGHT GAIN OF 27% WITH INCREASE IN DENSITY DOES NOT TRANSLATE INTO THE OPTIMUM DENSITY FOR DYEING OF COTTON YARNS
However for Polyester Yarns Optimal Density of Dyeing can be as high as : 440gpl Density before Compression Translates to 440 x 0.9 = 396 gpl Density After Compression : 440 gpl SOFT PACKAGE WEIGHT FOR 396 GPL POLYESTER PKGS PARTICULARS CONICITY
TO FIND DENSITY, FOR A PARTICULAR WEIGHT 0 DEG 0 MIN
EMPTY CHEESE OD IN MM
63
FULL CHEESE OD IN MM
180
TRAVERSE LENGTH IN MM
152
VOLUME IN CC NET WEIGHT IN GRAMS.
3.395,47 1350
DENSITY IN GMS/C.C.
0,398
PRECISION WOUND OPTIMUM DYE PACKAGE WEIGHT FOR POLYESTER SPUN YARNS : 1.350KGS DENSITY BEFORE COMPRESSION : 396 gms per litre DENSITY AFTER COMPRESSION : 440 gms per litre RANDOM WOUND OPTIMUM DYE PACKAGE WEIGHT FOR POLYESTER SPUN YARNS : 1.2KGS DENSITY BEFORE COMPRESSION : 360 gms per litre DENSITY AFTER COMPRESSION ( 22%) : 440 gms per litre
Let us study Yarn Hairiness Report with Increasing Soft Winder Speed Yarn Sample : 20s /2 Ne ; Yarn Hairiness Report
COUNT& 20/2PE, SSM 20/2 PE, SSM 20/2 PE, SSM 20/2 PE ,SSM SPEED 500MPM 800MPM 1000MPM 1200MPM S3 VALUE
522
569
675
920
CV%
35.9
27.1
14.2
15.3
MIN
283
337
522
815
MAX
1017
765
756
1158
Notice , how the S3 value goes up from 522 to 920 from a speed of 500 mpm to 1200 mpm for the same input yarn. The speeds of 800mpm is already the optimum speed for controlled Yarn Hairiness ( Though, S3 values will be influneced by the input yarn quality , however, we are here discussing the incremental increase in yarn hairiness relative to speed, considering same input yarns) If you are a leading supplier to a Branded shirt for weaving or knitting, or sewing thread maker then uncontrolled yarn hairiness is absolutely non acceptable. Yarn Hairiness is becoming a critical issue with all Textiles
In order to be fair to all Precision Winders , one has to say that quality of dyeing is better with Precision Winders on account of uniform density. However, on Package Dyeing , higher speeds and higher densities, both dont help.
Many Argue that Modern Dyeing Machines Pumps are strong enough to Flow the Liquor with Higher Package Densities.
It is not about Dyeing Machine Pump, but the Basic Technology of Dyeing, where Boundary conditions and Flow conditions which Define the Package Dyeing. Any increase in Flow Rate and Density results into Unlevelled Dyeing Let us Study What Happens When
Flow Rate Is Increased Or Density is Increased
To Get a Higher Thru Put From a Dyeing Machine
Let Us First Explore
What It Means To Increase The Flow Rate To Counter The Higher Density Packages
Modelling Fluid Flow Through A Yarn Package The Following Is Taken From Paper Published in RTJA Vol 9 No 3, 2005 By Zhou, Wardman ( Both from Heriot Watt University UK) And Shamey ( NC State University USA)
The system study in the model is a 2D cross Section of a Tube with a Layer Attached to the Poros Yarn Package In Yarn Dyeing : Dye liquor is pumped through a Tube and yarn assembly of package of 3D shape with space between each yarn layer filled with dye liquor. To Model the Flow Liquor in a Tube , the Navier-Stokes equation is employed to describe the flow velocity and pressure distribution within the package. We will escape the complex mathematical calculations and study the results of this modelling. The Modelling Domain and Boundary Conditions are shown in Picture Below ( Distances in Metres)
Distribution Of Flow Velocity In The Package Note the Fluctuations in Velocity on the Inner Surface of Package till the First 30 mm of Package Dia , before the Flow Velocity comes to a Steady State. Practical Meaning : Dark Shade In Inner Layers
Now Let us Study, what happens when the
Flow Rate Is Increased
Velocity Distribution Across Dye Package With Increase Inflow Solid Lines : Flow Rate 0.1 m/sec Dotted Line : Flow Rate 0.2 m/sec Shows, Higher The Inflow Rate Provided, Higher The velocity , but More Uneven Distribution of Flow Velocity Across the Package In addition Higher Flow Rates Give More Fluctuated Flow In Tube Which subsequently Increase The Shear Stress on Flow Properties Secondly, the Boundary conditions have been assumed in this article as No Slip Boundary. However in Real Time, there is a slippage and the Velocity Distribution Across Package is Far More Uneven.
The Paper Concluded In practice, the flow velocity within the yarn assembly can be increased by increasing the inflow rate. However. higher flow rate will lead to an uneven distribution of flow velocity through the yarn assembly And if an even distribution of flow velocity is important to achieve a level dyeing, a high flow rate is best avoidable .
PRACTICAL MEANING
HIGHER FLOW RATE DYES THE HIGHER DENSITY PACKAGE BUT GIVES UNLEVELLED DYEING WITH GUARANTEED DARK INNER LAYERS
Same like Driving Your Car Fast Car will Run Fast But You Feel Insecure and Bumpy
THERE IS AN OPTIMUM
FOR
EVERYTHING IN LIFE
INCLUDING WINDING AND DYEING
IMPORTANT IS TO ACHIEVE OPTIMUM AND BE CONSISTENT, RATHER THEN PEAK AND TROUGHS AND GO THROUGH STRESS STRAIN CURVE OF HIGH AND LOW
Let us Now Study Increasing The Density Of Dye Packages
MODELLING FLUID FLOW THROUGH DYE PACKAGE Pressure Drop AND Package Density Study conducted by Shannon, Hendrix, Smith and Montreo from NC College of Textiles USA
DYEING FLOW GEOMETRY We Will Study The Effect Of Increase In Density In Relation To Pressure Drop IN OUT AND OUT IN CYCLES Differences in yarn package density result in permeability variations, which directly affect flow behavior within the package ( we read this in Part I already ) The focus of this study is to develop a flow model that will allow a better understanding of the effects of yarn package and fluid properties on the dynamic flow behavior of process liquor dur-ing a yarn treatment process The model out-puts profiles for pressure, radial velocity and axial velocity for the yarn package as a velocity vector plot, as shown in figure below
Velocity Vector Plot In Relation to Radial and Axial Flow
Pressure Drop Vs Volume Flow Rate I/0 Radial Flow Note The Pressure Drop Increases As Density Profile of Package Increases. At highest density 660 gms per litre the package permatiability is lowest , though the flow rate is increased. ( There are certain Italian Dyers, who boost of dyeing at 660 gpl the polyester texturized yarns and this is the danger zone, which they play)
Pressure Drop Vs Package Diameter for O/I Flow with Pkg Density of 400 gpl Note With Mass Flow Rate Increase from 5 gpm to 15 gpm, the pressure drop increases with package diameter ( Model simulates gas flow and hence 5 gpm to 15 gpm against liquor flow of 25 gpl to 40 gpl)
These Slides Show Package Pressure Losses With Increase In Density Of The Package And Increase In Flow Rate When dyebath flow velocity is not uniform throughout the textile mass, the rate of dye uptake will not be uniform, leading to dyeing unlevelness. The influence of the diffusional boundary layer is illustrated in Figure below by the use of com- puted rate of dyeing curves.
The dashed lines in Figure repre- sent dye uptake under very low rates of liquor flow that result in a relatively thick diffusional boundary layer. The effect of the diffusional boundary layer increases with increase in bath exhausition. Meaning Change In pressure across the package causes variable hydrodyanamic boundary layers within the package. As this hydrodyanamic boundary layer thickens, the flow velocity changes
Right To Left Boundary Layer Thickens, Flow Velocity Drops
The Pictorial View of Pressure Drop With Increase in Package Density
DYE LIQUOR FLOW ACROSS VARIOUS ZONES OF DYE PACKAGE a - Flow When Dyeliquor Enters The Package b and e - Flow When the Liquor is on Edges of Package c and d - Flow In Inner Middle and Outer Middle f - Flow In Outer Layers
CONCLUSION PROCESS OPTIMIZATION OPTIMUM DYE PACKAGE WEIGHT : 1.2 KGS ( Cotton ) OPTIMUM SOFT WINDING SPEEDS ; 800 MPM OPTIMUM DYE LIQUOR FLOW RATES ; 25 TO 30 lits / Min or lower
OPTIMUM DYE PACKAGE CENTRE : MANTEX ECO CENTRE ULITMATE YARN DYEING MACHINE : Thies ULTIMATE SOFT WINDING MACHINE : SSM
RECAP USE OF DYETUBES = THROWING AWAY PROFIT UPTO $1 Million OPTIMUM DYE PACKAGE CENTRE : MANTEX ECO CENTRES OPTIMUM DYE PACKAGE WEIGHT : 1.2 kgs ( Cotton ) COMING UP NEXT OPTIMUM DYE SPINDLE DESIGN CYLINDERICAL OR TRIANGULAR
YOUR TECHNOLOGY PARTNER FOR YARN DYEING
MANTEX ECO CENTRES
#31/9, NCP Towers,1ST MAIN, 2ND Floor, Mount joy extension, Bangalore-560019 INDIA Phone: 080-22427863, mobile: 9743877863
E-mail: info@dyespring.net; mantexindia2012@gmail.com
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