Tuesday, January 25, 2022

HT-HP Package (cheese) dyeing machine, structure and working principle, advantages and disadvantages

Advantages of HTHP package( cheese) dyeing machine:


We make the dyed yarn through different processes. The dyed yarn can be made by adding colour during synthetic fibres production. The dyed yarn is also made by dyeing the natural fibres before spinning. The greige yarn is dyed after spinning by using either the hank dyeing method or the package (cheese) dyeing method. The package ( cheese) dyeing method has the below advantages over the hank dyeing method of yarn dyeing:

Knotless yarn results after package dyeing.

The material liquor ratio is less than the hank dyeing process.

The re-winding wastage is less than the hank dyeing process.

The washing fastness is very good in comparison to the hank dyeing process.

The shade variation is very hardly appeared in the package dyeing.

The dyeing of those yarns is possible in which the dye chemical get fixed above the boiling temperature. 

Dyes and chemicals consumption is less than the hank dyeing process. 

A bigger lot size is possible in the cheese dyeing process.

Less amount water is required in the cheese dyeing process. the effluent treatment cost is reduced in the cheese dyeing process.

Disadvantages of the cheese dyeing process:     

The cheese dyeing process has the below disadvantages:

The drying cost of the package dyeing is more than hank dyeing.

The bulkiness of the yarn is decreased.

The strength of the yarn is also decreased due to two times winding.

High care is required during the soft winding process.

Winding density variation in the soft winding process causes shade differences among the top, middle, and bottom layers of the yarn package.



Process sequence in the cheese (package) dyeing process:

The cheese( package) dyeing of yarn is completed in the below steps:

* Soft winding

* Colouration of yarn

* Hydro extraction

* Drying

Soft winding:

The soft yarn package in the cheese form is prepared before the dyeing of the yarn.

The yarn is transferred onto the perforated cylindrical tubes of standard steel springs or perforated nylon tubes.

A soft winding machine is used to prepare the soft packages.

The packaging density of the cheese is kept in such a way that the liquor could penetrate the material.

If the yarn is wound on the perforated nylon tubes, there should not be any uncovered space over the tube. 

The top and bottom edges should be equally soft as the body of the package.


Colouration of yarn package:

The scouring, bleaching, and dyeing of the yarn package are carried out in the HT-HP package( cheese) dyeing machine. We will discuss the structure and working principle of the HT-HP yarn package dyeing machine.

Structure and working principle of HT- HP

package dyeing machine: 

The different parts and their functions of the HT-HP package dyeing machine are as below:

Bobbin carrier:

It consists of the number of perforated spindles to hold the soft packages in the column. The perforations at the bottom of these carriers allow bi-directional circulation of dye and other chemical solutions through the yarn packages. 



Autoclave or cylindrical pressure vessel: 

It is a high-pressure cylindrical vessel. 

It is made of high-quality stainless steel. 

The dye bath is filled inside this vessel. 

This vessel is connected with many other accessories. 

The bi-directional liquor pump is connected to the bottom of this vessel. 

A high-pressure lid is fitted at the top of this vessel. 

A high temperature and high-pressure silicon seal is mounted between the top of the vessel and lid. 

This silicone seal makes the lid airproof and prevents the leakage of steam and liquor. 

The pressure gauge is mounted on the side of the vessel to see the inside pressure of the vessel. 

A suitable safety valve is mounted on one side of the vessel.

When the inside vessel pressure increases more than normal pressure due to any mistake or unknown reason, the safety valve releases the inside vessel pressure. 

The increased steam pressure pushes the safety pin of the valve against the spring and excess pressure is released automatically. 

Overflow valve is fitted at the top of the sidewall of the vessel. 

If the water level is increased above the required level, the excess amount of water is eliminated through the overflow valve. 

A drain valve is fitted at the bottom of the vessel. 

It drains the previous dye bath when required. 

The vessel is also connected to the freshwater supply line. 

A valve is mounted between the water supply line and vessel to control the freshwater supply. 

The pressure vessel is also connected with the dosing tank and preparation tank. 

A temperature sensor is mounted inside the pressure vessel.

This sensor gets in contact with liquor and sends a signal to the digital process controller.

 




Clour and chemical dosing tank:


A side tank is used for the colour or chemicals liquor dosing into the high-pressure cylindrical vessel. 

It is fitted at one side of the cylindrical vessel. 

It is connected to the preparation tank and pressure vessel. 

The required amount of the chemical or colour is dissolved in the preparation tank. 

The prepared liquor is sent into the dosing tank with the help of a feeding pump. 

A colour injector pump sends the liquor gradually according to the process parameter. 

Colour and chemical preparation tank:

The preparation of colour or chemicals liquor is carried out in this tank. 

The prepared liquor is also stored in this tank for the next process.  

A stainless steel tank is used, the required amount of the chemical or colour is dissolved in this preparation tank. 

A motorised stirrer is fitted inside the preparation tank. 

 Stirrer helps to blend and mix the colour or chemicals in the water properly. 

The preparation tank is connected to the dosing tank with the help of a pipe. 

High-speed colour circulation pump:

A high-speed liquor circulation pump is used to feed the liquor in the yarn package. 

A bi-directional liquor circulation pump is fitted in the machine.

The pump rotates in clockwise and anticlockwise directions. 

In the one cycle of the pump, the liquor flows from the inside of the cheese to the outside of the cheese. 

When the rotating direction of the pump is reversed, the liquor flowing direction is also reversed. 

Now, the liquor flows from the outside of the cheese to the inside of the cheese. 

Pressure gauge and safety valve:

The pressure gauge is mounted on the side of the vessel to see the inside pressure of the vessel. 

A suitable safety valve is mounted on one side of the vessel.

When the inside vessel pressure increases more than normal pressure due to any mistake or unknown reason, the safety valve releases the inside vessel pressure. 

The increased steam pressure pushes the safety pin of the valve against the spring and excess pressure is released automatically. 

Temperature sensor:

A temperature sensor is mounted inside the pressure vessel.

This sensor gets in contact with liquor and sends a signal to the digital process controller.  

Cooling coil:

In some types of yarns, the dyeing temperature is increased and reduced gradually. 

The cooling coil helps to bring the below down dye bath temperature gradually. 

Steam connection: 

The steam injection into the trough is carried out by a steam pipe connected between the steam supply and the liquor trough. 

An automatic steam supply valve is connected with this steam pipe to switch on/off the steam supply. 

If electrical heaters are used, this steam supply pipe is not required.

Water supply connection:

The liquor trough is connected with a freshwater supply pipe. 

A valve is used to start/stop the water supply in the liquor trough as per requirement.

Drainage pipe and valve:

The drainage pipe and valve are fitted at the bottom of the liquor trough. 

The water is drained into the wastewater line by this valve.

Air padding system:

The compressed air is supplied at the top of the high-pressure lid. the air is mixed with liquor. 

This air padding helps to reduce the material liquor ratio. 

The dyed and chemical costs are also reduced by this air padding system. 

Due to the low use of water, the effluent treatment cost is also reduced.

Digital process controller:

Basically, it controls the whole dyeing process. 

The required temperature is preset in the controller. 

The steam supply or electric supply of the heater is controlled by this digital controller. 

The processing time of each process is preset in this digital controller. 

Hydro extraction:

The yarn packages coming out from the machine contain a lot of moisture. 

The yarn packages are placed into the hydro extractor. 

The yarn packages are placed in the machine in such a way that it could not affect the centre of gravity of the machine after loading the yarn packages. 

In the other words, the weight of the material should be equally distributed in the machine during material placement. 

When the machine rotates, the maximum amount of water eliminates from the yarn due to centrifugal force getting developed during machine rotation. 

The yarn is taken out of the machine now.



Drying:

The yarn packages still contain an excessive amount of water in them after the hydro extraction process. 

Now, this moisture is evaporated by the drying process.

The yarn packages are dried in a hot air oven or radiofrequency drier, the yarn is placed in the hot air chamber specially designed for yarn packages. 

A blower fan blows the hot air upon the yarn. 

Electrical heaters or steam-heated pipes are used to heat the air. 

The heating temperature is kept around 105-110 degrees centigrade. 

The thermostat is used to control the inside temperature of the drying chamber. 

If the radiofrequency drier is used, the yarn packages are placed on the conveyor belt. 

This conveyor belt moves very slowly and carries the yarn packages inside the chamber. 

The yarn packages come out of the chamber after drying.

Yarn rewinding process:

The yarn is wound on the perforated nylon tubes or stainless steel springs. 

These tubes or springs are reused for soft winding many times and the cost of these tubes and springs is many times higher than the paper cones. 

When the drying of the yarn packages is completed, the yarn is transferred onto the paper cones with the help of a cone winding machine.


Sunday, January 23, 2022

Hank dyeing method ( yarn dyeing process)

 

Hank yarn dyeing process:

Colouration( dyeing) of textile materials ie fibres, yarns, fabrics, and garments is carried out by using different dyeing methods according to the form of the textile materials. If the textile material is dyed in the yarn form, the used dyeing process is known as the yarn dyeing process. There are two methods used to dye the yarn:

1- Hank dyeing method.

2- Package dyeing method.

Hank dyeing method:

If the yarn is dyed in the hank form, this yarn dyeing process is called the hank dyeing method of yarn dyeing. The hank dyeing process is carried out in an open vessel. The hank dyeing method has temperature limitations. The hank dyeing gets suitable for the dyeing of those yarn in which the colour gets fixed at 100-degree centigrade maximum. The different processes involved in the hank dyeing method are given below:

Hank preparation:

Normally, the yarn is sold in the package form( cone or cheese) now these days. There may be two possibilities ie dyer already has the required yarn in either hank form or in the package form. If the yarn is already available with dyer in the hank form, the hank preparation does not require in this condition. If the yarn is available with the dyer in the package form then the hank preparation process is required. The hanks are prepared with the help of a yarn reeling machine. If you work at a very small scale, the single end yarn reeling machine gets useful. In the case of large scale work, the multi-ends yarn reeling is used to prepare the hanks of yarn. 

Scouring, bleaching and dyeing: 

These processes are carried out in the hank dyeing manually or mechanical hank dyeing machine. The yarn hanks are loaded into the machine. The hanks are hung upon the rotating cylinders. The required water level is maintained in the colour and chemical trough. Now, the required chemicals liquor is prepared in the side tank step by step and dosing of each liquor is done one by one according to the process.

Structure and working of hank dyeing machine:

The basic structure of the semi-automatic hank dyeing machine is given below:

Colour and chemicals trough:

The colour and chemicals trough is made of stainless steel. The corrosion-resistant stainless steel is used for this trough. The water is filled in this trough during processing. The colour or chemical dosing is also carried out in this trough through the side tank. The yarn is impregnated into the colour or chemical liquor during the process. If the machine has a spray unit, the liquor is collected into this trough after spraying. The water supply pipe is connected at the top of the trough and the drainage pipe is connected at the bottom of the trough. A steam pipe is connected with the trough to maintain the required liquor temperature. This is the fixed part of the machine.

Side tank and colour dosing system:

A side tank is used for the preparation of colour or chemicals liquor and its dosing into the trough. A small stainless steel tank is used, the required amount of the chemical or colour is dissolved in the side tank. A motorised stirrer is fitted inside the side tank. The stirrer helps to blend and mix the colour or chemicals in the water properly. The side tank is connected to the trough with the help of a pipe. The controlled dosing of liquor is done manually by regulating the liquor dosing valve. 

Hank rotating cylinders and spray unit:

The hanks are hung upon hank rotating cylinders. These cylinders rotate in clockwise and anticlockwise directions intermittently. The perforated liquor spray pipes are also fitted with rotating cylinders and rotate together with these cylinders. The liquor sprays upon hanks by these perforated pipes. 

Liquor circulation pump:

The inlet of the liquor circulation pump is connected to the colour and chemical trough. The pump takes the liquor and feeds it into the perforated spray popes. The liquor coming out of spray pipis drops onto the colour and chemicals trough.

Motor and reduction gearbox arrangement:

A suitable reduction gearing arrangement is used to control the rotating speed of the hank rotating cylinders. The electric motor provides rotating motion is transferred to the hank rotating cylinders through the gearbox.

Cooling coil:

In some types of yarns, the dyeing temperature is increased and reduced gradually. The cooling coil helps to bring the below down dye bath temperature gradually.

Steam connection: 

The steam injection into the trough is carried out by a steam pipe connected between the steam supply and the liquor trough. An automatic steam supply valve is connected with this steam pipe to switch on/off the steam supply. If electrical heaters are used, this steam supply pipe is not required.

Water supply connection:

The liquor trough is connected with a freshwater supply pipe. A valve is used to start/stop the water supply in the liquor trough as per requirement.

Drainage pipe and valve:

The drainage pipe and valve are fitted at the bottom of the liquor trough. The water is drained into the wastewater line by this valve.

Temperature sensor:

The sensing part of the temperature sensor is fitted inside the trough and it gets in contact with liquor. The temperature sensor is connected to the digital controller through a cable. It sends a signal to the digital controller.

Digital process controller:

Basically, it controls the whole dyeing process. The required temperature is preset in the controller. The steam supply or electric supply of the heater is controlled by this digital controller. The processing time of each process is preset in this digital controller. 

 Scouring:

If we dye cotton yarn or any other cellulosic yarns, the scouring of the yarn gets compulsory. The natural impurities present in the yarn are removed in this process. First of all, the yarn is treated with caustic soda, a wetting agent, and a sequesting agent. 

If the re-generated and manmade yarns ie viscose rayon, bamboo rayon, modal, and Tencel are dyed, the yarn is washed with hot water and treated with a wetting agent only. 

Bleaching:

The bleaching process is used for natural cellulosic fibre only before dyeing. The hydrogen peroxide and peroxide stabilizing agents are added to the bath in the next step. The temperature is raised up to 90 degrees centigrade.  The bath is drained finally. The yarn is now washed with fresh water and treated with peroxide killer to remove the residue of hydrogen peroxide. The yarn is treated with mild acetic to neutralise the material. The yarn gets ready for the colouration process. This process gets bypassed in the case of re-generated and manmade yarns ie viscose rayon, bamboo rayon, modal, and Tencel or synthetic yarns.

Colouration(dyeing):

The required water level is maintained in the colour and chemical trough. Now, the dye and other chemicals are dissolved in the side tank. The dosing of the liquor is done gradually in the dye bath. The fixing agent and exhausting agent are dosed in the dye bath according to the standard dyeing process.  The temperature is raised up to a certain point. As the required shade is achieved, the dye bath is drained. Next, soaping is done to remove the unfixed colour from the yarn and the yarn is washed with fresh water and neutralised with mild acetic acid. Finally, yarn is treated with a fixing agent and the bath is drained. the material is taken out from the machine. 

Hydro extraction:

The material coming out from the machine contains a lot of moisture in it. The yarn hanks are placed into the hydro extractor. The material is placed in the machine in such a way that it could not affect the centre of gravity of the machine after loading the material. In the other words, the weight of the material should be equally distributed in the machine during material placement. When the machine rotates, the maximum amount of water eliminates from the yarn due to centrifugal force getting developed during machine rotation. The yarn is taken out of the machine now.



Drying:

The yarn still contains an excess amount of water in it after the hydro extraction process. Now, this moisture is evaporated by drying the yarn either by sun-drying or by hot air oven. In the sun drying process, the hanks are hun upon the wooden structure. The yarn is exposed to the sun light, the moisture is evaporated, and the yarn is dried after a certain exposure yarn to sunlight.

If the yarn is dried in a hot air oven, the yarn is placed in the hot air chamber specially designed for hank yarn. A blower fan blows the hot air upon the yarn. Electrical heaters or steam-heated pipes are used to heat the air. The heating temperature is kept around 105-110 degrees centigrade. The thermostat is used to control the inside temperature of the drying chamber.


Hank to cone winding:

The hank yarn can not be used directly in the weaving knitting or stitching process. The hank yarn is required to convert it into the cone form. Now, the dried yarn passes through the hank to the cone winding machine. The hanks are converted into the cone form after this process.

Please click on the below video link to watch the full article in Hindi:



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Saturday, January 15, 2022

Structure and working of jigger dyeing machine(Ā fabric dyeing machine)

Jigger dyeing machine(a fabric dyeing machine):

* The jigger machine is a fabric dyeing machine. this machine is getting used for a long time for the dyeing of the woven fabric. 

* The scouring, bleaching, and dyeing in the full-width form are carried out by the jigger dyeing machine.  

* The scouring, bleaching, and dye solution is filled in the trough. 

* The fabric passes through the medium of chemical solution at the bottom of the machine from one roller to another.

When all the fabric from one roller has passed through the bath and the fabric gets transferred on the other roller, the moving direction of the fabric is reversed.

Each fabric passage from one roller to another roller is called "end"  

The number passages are always kept in even numbers in the jigger machine process

Various processes carried out in Jigger machine:

Combined scouring and bleaching is carried out in Jigger machine Dyeing and washing:

The object of dyeing is a uniform application of colouring matter on textile material.

Dyeing in the jigger machine is called the “Exhaust dyeing” technique.

Careful control of the dyeing temperature, pH and auxiliary chemical concentrations is often necessary to obtain level, well-penetrated dyeing.

After dyeing, the material is rinsed to remove unfixed dyes and so it may need additional washing in the jigger dyeing machine.

Basic structure and working principle of the

modern Jumbo Jigger machine:


Fabric passage in jigger dyeing machine:



Colour and chemical trough:

The colour and chemical trough is made of good quality stainless steel. The guide rollers are fitted on the steel frame. These guide rollers guide the fabric during fabric passage in the liquor. This colour and chemical trough is designed in such a way that its design allows a constant and controlled liquor ratio in the dyeing process. The colour and chemical trough also allow washing at high efficiency with minimum liquor content. The intended liquor ratio is a minimum of 1:4. 

Stainless steel compartment:

The machine consists of an enclosed stainless steel compartment with 6 mm thick sides. This compartment has inclined doors and heated door frames, which prevent dripping of condensate on the fabric.

Take-up and Let-off rollers:

Two stainless steel rollers are used in the jigger dyeing machine. One is called a take-up roller and the other is called a let-off roller. These rollers move on the bearings. The fabric is wound upon these rollers during operations. The fabric being processed is transferred on one roller by a suitable arrangement. Now, the fabric passes through the bath and gets wind upon another roller. When the almost complete fabric is wound upon the second roller, the machine stops and the roller's moving direction gets reversed. This operation continues till the end of the process. 

 


Liquor circulation pump: 

The liquor circulation system consists of the centrifugal pump. This pump generates a pressure of two bars. Internal plastic net helps to separate the big particles from the liquor. The circulation pump is connected to the stainless steel piping of the water spraying system. A manual flow control valve and deflector system are used for even liquor distribution

Quick liquor discharge:

A large diameter pneumatically controlled drain valve is used for quick liquor discharge. it allows short change over time of water.

Fabric unloading system:

There is one stainless steel guiding frame supported by 2 air cylinders for single unloading, including a fixed stainless steel fabric spreading bar and a mechanical safety lock.

Stainless steel side tank:

The machine is also provided with a stainless steel side tank of 300 litres capacity with direct manual heating. The tank is equipped with a plastic net, manual drain valve, automatic mixer, level sensor, re-circulation connection and rinsing rim for automatic cleaning.



Water spraying system:

The objective of the water spraying unit is to spray the chemical or colour solution upon the fabric surface during the process. A circulation pump is used to feed the chemical or colour solution to the nozzles. The nozzles are fitted in the two hollow pipes. Each hollow pipe is mounted on each side of the machine. When the pump lifts the colour solution and feeds it to the hollow pipes, the chemical or colour solution comes out of nozzles at high pressure. The solution coming out of nozzles sprays on the fabric surface at both sides of the machine. The spraying solution drops in the trough. this cycle is repeated continuously.


Special features of modern jigger machine:

Modern jigger machines such as jumbo jiggers consist of full automation. 

A.C. drive.

Tension regulation and control system. 

Fabric speed regulation system. 

Fabric measuring system. 

Smooth and jerk less during stop and start.

Number of turns counter meter.

Gradual and noiseless reversal.

Automatic temperature regulation and control.


  The typical recipe for various processes in

  the jigger dyeing machine:

 A typical recipe for various processes in the jigger dyeing machine is given below:

 Combined scouring & bleaching:

Hydrogen Peroxide ( Bleaching agent)                           - 2-5% 

Caustic soda ( Scouring agent)                                        - 1-2%

Wetting agent (Improve wetting tendency of fabric)   - 0.1-0.5%

Sodium silicate ( Peroxide stabilizer)                              - 1-3% 

Sequestering agent ( To reduce the hardness of water)  - 0.5%


Dyeing and washing:

Reactive dyes ( Colouring agent)                                    - 2-4%

Wetting agent (Improve wetting tendency of fabric)        - 0.5%

Sodium chloride (Exhausting agent)                                - 5%

Sodium carbonate (Fixing agent)                                     - 1-2%

Soap (Removing unfixed dyes)                                        - 0.5%


Advantages of jigger dyeing process:

The jigger is a short liquor dyeing machine for textile fabrics in open-width form. 

The small lots can be easily processed economically in a jigger dyeing machine.

* The jigger dyeing machine is the most suitable for all kinds of shades.

Excellent colour fastness properties of the dyed fabric are achieved in the jigger dyeing machine.

The investment cost is lower than the continuous dyeing technique.

* The jigger dyeing machine is suitable for all kinds of processes in open width, from pretreatment to finishing. 

Disadvantages of jigger dyeing process:

*  When the lightweight fabrics ( open perforated fabric) are dyed on the jigger dyeing machine, the more chances of yarn slippage get possible. 

* The lot size gets too much smaller than the continuous dyeing process.

* There is always a chance of some fabric damage at both ends of the batch.

* If the stitching thread is not selected properly, there,  the impression marks of the stitching thread may appear at both ends of the batch.  

* If the pieces are not stitched accurately according to the direction of residual bowing, the bowing in the fabric may be increased during processing.

* If a fabric has the skewing, the shade difference between selvedge and body fabric may appear.

* When the fabric is dyed on the jigger dyeing machine, the moderate tension on the fabric gets applied throughout the process. The fabric gets elongated and warpwise shrinkage gets increased. 


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HT-HP Package (cheese) dyeing machine, structure and working principle, advantages and disadvantages

Advantages of HTHP package( cheese) dyeing machine: We make the dyed yarn through different processes. The dyed yarn can be made by adding...