1. ASSIGNMENT
ON
JET DYEING MACHINES
COURSE NAME : TEXTILE WET PROCESSING 2
COURSE CODE : TEX - 301
Submitted To :
MD:MAHBUBUR RAHMAN
Senior lecturer
Department of Textile engineering
Green University of Bangladesh
Submitted By :
Amit Biswas
ID : 143003014
Department of Textile engineering
Green University of Bangladesh
2. Jet dyeing machine:
This is the most modern machine used for the dyeing of polyester using disperse dyes. In this
machine the cloth is dyed in rope form which is the main disadvantage of the machine.
in this machine, the dye tank contains disperse dye, dispersing agent, leveling agent and acetic
acid. The solution is filled up in the dye tank and it reaches the heat exchanger where the solution
will be heated which then passed on to the centrifugal pump and then to the filter chamber.
Jet dye machine is the most modern machine used for dyeing of polyester using disperse dye.
It is similar to winch dyeing and fabric is processed in continuous loop.
The technique is especially useful for delicate polyester fabrics but depending on the machine
almost any weight, structure, or fabric type can be used.
It was found that in using winch machines, there were some inherent problems. So the jet dyeing
machines when they came up in the 1970's, were specifically designed to overcome those
shortcomings.
In this machine the dye tank contains disperse dye, dispersing agent, leveling agent and acetic acid.
Fabric may be jet dyed by placing it in a heated tube or column where jets of dye solution are
forced through it at pressure up to 300 pounds per jet.
Working process of jet dyeing machine:
In the jet dyeing machine the reel is completely eliminated. A closed tubular system exists where
the fabric is placed. For transporting the fabric through the tube a jet of dye liquor is supplied
through a venturi. The jet creates turbulence. This helps in dye penetration along with preventing
the fabric from touching the walls of the tube. As the fabric is often exposed to comparatively
higher concentrations of liquor within the transport tube, so little dye bath is needed in the bottom
of the vessel. This is just enough for the smooth movement from rear to front. Aqueous jet dyeing
machines generally employs a driven winch reel along with a jet nozzle.
3. Machinery process:
• The solution is filled in the dye tank and it reaches the heat exchanger where solution can
be heated which then pass onto the centrifugal pump and then to the filter chamber.
• The solution will be filtered and reaches the tubular chamber. Here the material to dye will
be loaded and the winch is rotated so that the material is also rotated.
• Again the dye liquor reaches the heat exchanger and operation is repeated for 20-30 minute
at 135°c.
• Then dye bath is cooled down, after material is taken out.
Special features and application:
• This machine can be operated at high temperature and pressure .
• This system operate at low liquor ratio (ratio of mass of dye bath to mass of fabric in dyeing
machine) so, this operation consume less water and chemical.
• Frequent movement of fabric round the jet through the machine reduces the tendency of
crease formations.
5. Types of jet dyeing machine:
• After incest fating the dyeing results under different conditions such as development of
new fiber blends, different construction fabrics, interaction position of jet, quantity of the
dye liquor to be present in around the fabric and the type of impact of the dye liquor on the
fabric in the jet area.
Some jet dye machines are as follows:
• overflow dyeing machine
• soft-flow dyeing machine
• Airflow dyeing machine
6. Advantages jet dyeing machine:
dyeing time is short compared to beam dyeing.
material to liquor ratio is 1:5 (or) 1:6
production is high compared to beam dyeing machine.
Low consumption of water.
Short dyeing time.
Can be easily operated at high temperatures and pressure.
Comparatively low liquor ratios, typically ranges between 1:4 and 1:20.
Fabrics are handled carefully and gently.
7. Disadvantages jet dyeing machine:
cloth is dyed in rope form
risk of entanglement
chance for crease formation.
Cloth is dyed in rope form so there is a risk of entanglement and chance for crease
formation.
Equipment and maintenance costs are high, foaming can be a problem, and some fabric
may be abraded in the process.
Chance for crease formation.
Limitations of jet dyeing machine:
• High initial investment and maintenance cost.
• Limited accessibility during the dyeing process.
• Foam forming substance is to be avoided.
• Any roughness of the inside surface cause damage to cloth.
• In case cloth breakage, re-threading is complicated.
Main parts of dyeing machine:
1. Main vessel or chamber
2. Winch roller or reel
3. Heat exchanger
4. Nozzle
5. Reserve tank
6. Chemical dosing tank
7. Utility lines i.e. water line, drain line, steam inlet etc.
8. Controlling unit or processor
9. Fabric plaiter
10. Different types of motors & valves
16. Autoclave: in horizontal and conical construction equipped with a port and cover for the fabric
loading in the front. The group and polished reel and separator are located inside the autoclave is
pressurised by compressed air. Pressure guage and necessary safety values are provided.
Main dia of the autoclave : 600 mm
straight part of the autoclave : 7000 mm
Flow tubes: flow tubes are made of stainless steel and are highly polished and connected to the
autoclave. Necessary flow control valves and by pass valves for the fine adjustments of flow
quantity are provided.
Main liquor circulation pump: for the liquor circulation and fabric movements and efficient
centrifugal pump made of stainless steel is provided. The pump is driven by directly coupled to
fully enclose two pole induction motor of 20 h.p.
Heat exchanger: heat exchanger is made from stainless steel. The heat exchanger is of shell and
tube type construction and is entirely mode of stainless. The heat exchanger is suitable for raising
temperature of the dye liquor from 30'c to 130'c at a steam pressure of 4.0 kgs./cm2. The heat
exchanger is suitable for cooling down the dye liquor from 1.3'c to 8o'c.
Reserve tank: one reserve tank made of stainless steel is provided outside the high pressure
circuits for the preparation to dyestuff and chemicals.
Miscellaneous :
• One filter for the heat exchanger.
• One lamp is provided on the top of the autoclave for efficiently illuminating the inside of
the autoclave.
Draw reel: one draw reel with necessary drive is provided on the front top of the autoclave near
the cover suitable for loading and unloading of the autoclave.
Control panel:
The following controls are provided.
Temperature indicator and automatic temperature controlling instruments.
On/of swatches for the operation of pumps and other control.
Indicating lamps etc.
Pneumatic circuits controls.
Nozzle: one no. Jet nozzle will be supplied with the machine.
Scope of supply :
17. One autoclave complete with all the internal pipelines. Valves, foundation block
and other such parts necessary for normal operation.
One control panel as above.
One draw reel as above.
Sample dyeing machine
21. Soft-flow dyeing machine:
Soft flow dyeing machine, which ensures even dyeing with low tension and accurate rinsing
system.
Fabricated as per international quality norms, this device is widely appreciated for hosts of
outstanding features like trouble free service life, optimum functionality and energy efficiency.
22.
23. Back view of a dyeing machine
Jet dyeing m/c (inside view)
24. Jet nozzle
Air-flow dyeing machine:
This is another development of the very popular jet dyeing machines. The main difference
between the air flow machine and jet dyeing machine is that the airflow machine utilizes an air
jet instead of the water jet for keeping the fabric in circulation. Typically the fabric is allowed to
pass into the storage area that has a very small amount of free liquor. This results in a reduction
in consumption of water, energy and chemicals. The figure below shows how in an airflow
machine the bath level is always under the level of the processed textile. Here the fabric does not
remain in touch with the liquor (the bath used is below the basket that holds the fabric in
circulation). This invariably means that the bath conditions can be altered without having any
impact on the process phase of the substrate.
Description
Discontinuous processing of textile substrates require more water and energy compared to
continuous processes. However, for a long time efforts are undertaken to optimise discontinuous
processes with respect to productivity, efficiency and also to minimise energy and water
consumption respectively. This lead to dyeing jets. Thereby liquor ratios have been reduced step
25. by step. The latest developments have lr of 1:3 (for woven pes fabric) and 1:4.5 (for woven co
fabric). To achieve such low lr, within the machine (jet), the fabric is moved by moisturised air
or a mixture of steam and air only (no liquid) along with a winch. The prepared solutions of
dyestuffs, auxiliaries and basic chemicals are injected into the gas stream. The bath level is
always below the level of processed textiles in order to maintain low lr. The principle of such an
airflow dyeing machine is illustrated. Rinsing is carried in a continuous manner. During the
whole rinsing process, the bottom valve is open and rinsing water is discharged without
additional contact with the fabric (which is the case in conventional machines) this also
allows the discharge of hot bath liquors, also after high-temperature dyeing at 130°c. Thus, in
addition to time saving, optimum heat recovery can be performed. The fabric itself is processed
with low tension and crease formation is minimised.
