Hank Dyeing In HTHP Machines

Dyeing of hanks in multipurpose HTHP dyeing machines The HTHP dyeing machines can also be used for dyeing and bleaching of yarn in hank form ,by using suitable carriers on which the hanks can be loaded. The fiber dyeing carriers can also be used in which the hanks are piled ,just like in kiers, and dyeing or bleaching can be done. The last method is useful for hard twisted and coarser yarns, which are difficult to penetrate under normal atmospheric conditions of cabinet dyeing machines. The hanks are loaded into suitable dyeing carriers , which are having either straight sticks or circular sticks for loading of hanks. The hanks of different sizes can be accommodated as in the case of cabinet dyeing machines. The carriers are then put into the dyeing machine kier and rest of the process is carried out as in case of cheese dyeing . The flow rate and reversal of dye liquor direction are optimized as per the quality of the yarn.

Spray Dyeing Machines

1.Lid
2 .Regulation valve
3 .Addition/expansion tank
4 .circulating pump
5.window
6. injection tube( spray arm)
7.Collection tank Intake
8.Machine body

These machines can be defined as an improved version of roller dyeing machines or hybrid type of machines with combination of features of roller dyeing and cabinet dyeing.

The features incorporated in these machines are especially important to overcome the problems related to delicate yarns such as silk , viscose and wool yarns.

These machines are made of rectangular shaped box type enclosed main body, in which the spray arms are located ,there is collection tank with heating coils at the bottom.

These machines have removable loading arms ,same as in roller dyeing machines ,but having perforations for spraying the dye liquor from inside the rollers. These arms have an arrangement also fitted with suitable spray pipes for spraying the dye liquor from outside as well inside of the hanks . The arms rotate on their axis with the hanks thus spraying the dye liquor from both inside and outside of the

hanks ,covering uniformly the entire hank.. The excess liquor is collected at the bottom tank ,from which it is again fed to the spray system with the help of a centrifugal pump. The spray pressure and flow rate can be adjusted as per the material quality and type of hanks. The RPM and direction of rotation of the arms can be varied according to the yarn quality and process parameters, to get uniform dyeing results and to avoid the yarn entanglements.

Main features of spray dyeing machines are
1. The machines are specially built for processing of delicate yarns such as wool , wool blends, silk and viscose yarns.
2. the yarn is treated very gently , and have minimum mechanical abrasion , the impact of dye liquor turbulence on the yarn is also minimum ,thus minimum entanglement and mechanical damage during processing.
3. The liquor is fed through an inverted controlled centrifugal pump ,so the liquor circulation in liters / min/ kg can be adjusted as per requirement as well as when the machines are used at a reduced capacity.
4. Total liquor volume of the machines can be adjusted as per loading or number of arms in the use.
5. The entire dyeing cycle can be carried out in fully automatic mode with the help of with the help of microprocessor based programmer.
6. The arms can be removed and replaced easily, therefore it is also possible to keep a lot ready on a spare set of arms ,which can be easily replaced after the completion of a dyeing cycle. The machines can be used at reduced capacity by reducing the number of arms in operation and more flexible.
7. The machines are available with air pad facility to run the machine at higher temperature and pressure and also keeping the constant liquor ratio when used at reduced loading.
8. Similar machines can be coupled together for dyeing of bigger lots in the same shade.
9. The machines are equipped with a single addition tank ,which is used for injection of dyes and chemicals through a separate pump. Fully automatic machines can be connected with automatic color kitchen also.
10. The machines are equipped with a sampling device to draw a sample for shade inspection without interrupting the dyeing operation .

Cabinet Hank Dyeing Machines

These are the most popular hank dyeing machines, these machines are designed to have liquor flow parallel to the yarn and they work with low liquor ratios to save substantially in consumption of thermal energy ,water and chemicals.The material to be dyed in hanks is loaded on the sticks ,generally two sticks are used one at the top and other at the bottom. The bottom stick is used to avoid the yarn entanglement during the liquor flow. The carriers are loaded with the sticks having hanks ,the sticks are supported into slots made in the body of the carrier.

The loaded carriers are then put into the dyeing machine and door is closed. In a second variant of the machine , the machine is open at the top and career is loaded from the top , which ,a rubber gasket is provided around the periphery on which the machine career rest, and vessel is sealed by the weight of the career and material, thus making closed circuit. The liquor circulation and flow remains the same as in ordinary cabinet machine.

The dye liquor in these machines moves while the material remains stationary. The flow direction is reversed frequently to ensure level dyeing.

A cabinet dyeing machine consists of following main components,

1.Main dyeing vessel made of SS
2.Carriers for loading of hanks with SS sticks for loading of hanks.

3.An internal axial pump or an external pump for liquor circulation.

4.An indirect heating system(with internal or external heat exchanger)

5.An addition tank with injector pump

6.Prepartion tank

7.An internal or external sampling device
8.Color kitchen

Main features of the cabinet dyeing machines are,

1.These machines are most researched ,developed and technically advanced ,and these are most preferred choice for the dyeing of all types yarn in hank form.

2.Modern machines are more flexible and capable of partial or half loading ,without changing the M:L, by using either dummies or by using special loaders , which can be easily adjusted in the machines. The new machines are equipped with continuous variable volume control and monitoring system ,which maintains the M:L even at reduced load .

3.Machine capacities available with same material to liquor ratios ,from lab scale to 1000 kgs for bigger lot size. Coupling of similar capacity machines is also possible to get even bigger lots.

4.All features such as inverter controlled pumps ,dosing and automatic color kitchen and fully automatic dyeing controllers ,same as package dyeing machines are available in these machines.

5.These machines are suitable for dyeing of various sizes of hanks ( from 48” to 90 “) in different qualities such as cotton, viscose, cotton blends, acrylic, wool and its blends and nylon etc. without any problem.

6.The liquor ratio of machines varies between 1:10 to 1:15, depending upon the machine and quality of material to be processed.

7.In the machines with air pad technology , the air pad acts as a air cushion to take care of expanded dye liquor and it is possible to work with higher pressure and temperture The machines with air pad are capable of working up to a maximum temperature of 135 0 C and there is no need of an extra heat exchanger to cool down the expanded dye liquor. Since the machine works in a closed circuit mode ,therefore the entire dye liquor participate in the dyeing.

8. The machines may be having a preparation tank with a quick transfer pump for faster liquor transfer from and to the machine without losing time and reducing the overall dyeing cycle. New machines are equipped with automatic color kitchen , multiple feeding and drainage points for more efficient and cleaner working.

9.The machines are equipped with an internal or external sampling device ,which allows the inspection of samples at any point of dyeing cycle ,without disrupting the actual dyeing process.

10. The machines with interchangeable extra careers offer mach more flexibility in terms of saving in loading /unloading time as well as automation of loading and unloading.

Roller Hank Dyeing Machines

Roller hank dyeing machines
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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 SS tank with proper heating mechanism (either a heating coil or direct steam injection through a perforated steam pipe) 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 SS rollers/poles which are fitted on a suitable frame .The rollers can rotate in clockwise or anticlockwise directions with the gears arrangement. The machine is fitted with a 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. The speed (RPM) of rollers can be varied by changing the gears and rotation cycles are controlled by timers which change the direction of movement of motors.
The dyeing vat have the filling and draining facility of dye liquor. The dyes and chemicals are added directly into the dye vat.
Operation of the machine
The hanks to be dyed are loaded onto the rollers bars by avoiding overlapping of hanks, in lifted position. The dye bath is kept ready with proper liquor level ,and mixed homogenously ,preferably with an external circulation pump .The hanks are lowered into the dye bath and movement is started , approximately 40-50% part of the hanks remain the liquor and rest is exposed to atmosphere . The material is lifted up for addition of colors ,chemicals ,salt, alkali etc or for raising the temperature of dye bath(in case of direct steam injection). In case of indirect 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 and disadvantages of Roller Hank Dyeing machines
1.Roller dyeing machines are simple in design and operation
2.Cost of the machine is not very high
3.Almost all type of dye classes such as direct, reactive, vat, naphthols, pigments, soluble vats can be applied to cotton ,mercerized cotton or rayon filaments.
4.All types of yarns can be processed such as cotton, mercerized cotton, viscose filament or even silk can be processed . The machines with simple modifications can be used to produce tie and dye effects in bigger lots particularly in cellulosic substrates.
5.The machine capacity depends upon the number of rollers ,which could be from 1 to even 10 rollers, and each roller can handle from 2 to 4 kg of yarn.
6.Only 40-50% of yarn takes part in dyeing and rest is exposed to atmosphere, therefore hydrosulphite consumption is high in these machines.
7.The machines are open type ,therefore maximum dyeing temperature is 95-98 0C .
8.The liquor ratio increases with heating in case of direct injection of steam.
9.Liqour ratio is high ,generally 1:15 to 1:20, therefore chemicals, steam and water consumption is comparatively high.
10.The yarn entanglements takes place during running which reduce the hank to cone winding efficiency.
11. Only limited automation is possible.
12. The dyeing is carried out under atmospheric pressure and there is no liquor pressure ,therefore the color penetration in hard twisted material is poor.

Hank Dyeing Machines

Processing of yarn in hank form
why hank dyeing?
Although package dyeing route is much simple and easy to follow for dyeing of different kinds of yarn ,but still the hank route is popular for certain qualities, there are two reasons for this,
1.The quality and nature of the product does not allow to follow package route
2.The package route is non practical and non economical.
Product quality
Certain kinds of yarns which are so delicate that their physical properties such as strength appearance ,texture and construction can not be retained while following the package route in which yarn is processed under stretched conditions at elevated temperatures. The examples of such products are natural silk, viscose rayon., voluminous yarns, High bulk acrylic , shrink resist treated wool and its blends. Cashmere ,its blends with wool and nylon ,nylon and hand knitting yarns of different fancy constructions.
Economy of process
In case of mercerized cotton yarns , the yarn mercerizing is done in the hank form and material has to be neutralized before dyeing ,therefore it is not economical to convert these hanks to packages for dyeing.
Process sequence for yarn dyeing in hank form
1.Singeing(for mercerized cotton yarns)
2.Reeling
3.Mercerization (for mercerized cotton yarns)
4. Dyeing
5.Hydro extraction or squeezing
6.Drying
7.Hank to cone wiinding
Process Flow Chart of Hank processing

Dyeing in Hank Form

Type of different Hank dyeing machines

1.Roller hank Dyeing machines

2.Cabinet Dyeing Machines

3.Spray Dyeing Machines

4.Vertical Kier Machines
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Reeling

Reeling or making of hanks

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The Reeling is a procedure which converts yarn into commerically portable form. The outcome of reeling is called hanks or skeins. It is normally done after twisting/Winding to wrap yarn carefully for processing in hank form and unwinding it later. The reeled yarn is carefully tie-banded to control fibres during handling, scouring, Dyeing and unwinding.

These machines are used to convert the yarn in hank form .The hanks produced as per the quality of yarn ,further processing facility such as dyeing, drying ,hank to cone winding etc.

Mail characteristics of hanks are

1.Hank diameter

2.Hank weight

3.Hank traverse

4.Crossing angle such as diamond.

5.Formation of hank such as rectangular ,trapezoidal, cop built or lea hanks.

Main features of a reeling machine

1.Swift and its circumference setting

Hanks of various sizes such as weight ,circumference, width and make up are used depending upon the substrate quality (cotton, viscose, silk, wool, acrylic etc ), physical and aesthetic features of the yarn, end use ,further processing machinery set up such as mercerizing, dyeing ,hydro extraction , drying and hank to cone winding. Generally 54 “(1370 mm) to 90 “(2286 mm) circumference hanks are used

In most of the cases the swift of the machine is adjustable to accommodate the different circumferences or swift sets are available for particular ranges such as in crune luke machines 3 different sets are available

swift circumferences:

1. Size 1 1.350 – 1.524 mm

2. Size 2 1.500 – 1.905 mm

• Size 3 1.800 – 2.337 mm

2.Yarn guide system

The yarn laying system has thread guides which are controlled electronically for changing the hank features , type of hanks and to select different crossing angles.

3.Hank doffing system

The doffing could be manual or automatic after the completion of hanks.

4.Hank parameter setting or type of hank

Different types of hank formation or lay out can be made depending upon the type of yarn and further processing machinery such as,

rectangular

trapezoidal

cop-built

lea-hanks

A trapezoidal or tapered end hank

5.Hank positions

It is the number of hanks which can be made on the full machine ,with a particular set of parameters. The hank positions are less when the hank width or traverse is more.

6.Leasing system

Leasing is tying the hanks at various places(1-6) with stronger threads or yarns by inserting the thread throughout the traverse at selected points. Generally leasing in the hanks is done manually to keep them intact in the further processing such as mercerizing, dyeing, hydro extraction, drying and to facilitate efficient and trouble free hank to cone winding. There are different systems for leasing as shown below

double eight

one and a half eight

single eight

in crune luke machine automatic leasing system CLT is available.

7.Length measuring system

Modern reeling machines are equipped with length measuring devices to keep the yarn length

constant from one hank to another ,to get a uniform hank weight for better results in further

processing such as dyeing and to make uniformsize packages in hank to cone winding.

8.Hank width setting or traverse

The traverse or width of hanks is important for a particular hank weight to get uniform results in further processing, generally a range from 80 mm to 380 mm is available from the different manufacturers.

9.Yarn tension control system

The yarn tension from the feed package is regulated to get the uniform reeling results and precise winding in all the hanks. Modern reeling machines are equipped with automatic yarn tension control system

10.Reeling speed and maximum obtainable hank weight.

The reeling speed depends upon the number of factors such as type of yarn and required hank weight and circumference. The machines are available with a maximum winding speed up to 1500 m/min. Hank weight is also decided by the set up of further processing machinery as well as the type of yarn processed . The maximum hank weight as per the different manufacturers is up to 2.5 kg . For mercerized cotton yarn a weight of 1-1.5 kg is generally adopted.

11.Crossing angle and diamond

It is distinct characteristic of hank for uniform dyeing and efficient hank to cone operations. It could be selected in a step less manner or diamond formation as shown below from 1:1 to 1:6.

12. Splicing and yarn clearing system

To avoid the manual knotting in case of yarn breakage and yarn faults to be carried forward in further processing.

Silk Reeling and Re reeling

Fadis Sincro Technology

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