1 | P a g e Dyeing m/c

Chapter 2

Dyeing M/C The basic requirements of a dyeing m/c: 1. It should provide sufficient provement for the liquor to penetrate uniformaly into every parts of the goods. 2.The movement must not be so vigorous that it will damage fibre mtls. 3.The m/c must be constructed of a mtl. Which will withstand prolonged boiling with acid or alkaline solutions. 4.The heating arrangements must be such that a comparatively uniform temp will be maintained throughout the liquor. 5.There should be some means of adding the concentrated yestuff solution in such a way that it becomes well diluted before it comes into contact with goods. 6. All moving parts and electric motors should be protected against the corrosive action of steam and acidic atmospheric condition. Types of dyeing m/c:

Fibre dyeing m/c. Yarn dyeing m/c. Fabric dyeing m/c.

Fibre dyeing m/c: (Loose stock form): a) Conical pan loose stock dyeing m/c. b) Annular cage for loose stock dyeing m/c c) Hussong loose cotton dyeing m/c. d) Jagen burg dyeing m/c. e) Clauger-weldon m/c.

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f) Simplex dyeing m/c. g) Dreze dyeing m/c. h) Ober maier dyeing m/c. i) Long close loose cotton dyeing m/c. Yarn dyeing m/c: 1.Hank from: I. Hussong hank dyeing m/c. II. Pulsar hank dyeing m/c. III. G.S.H hank dyeing m/c. IV. Clauder Weldon hank dyeing m/c. 2.Package form: I. Cop dyeing m/c. II. Cheese dyeing m/c. III. Warp dyeing m/c. a) Cop dyeing m/c. - Mather & Platt cop dyeing m/c. - Long close cop dyeing m/c. - Beaumosent cop dyeing m/c. b) Cheese dyeing m/c: - - Ober maier cheese dyeing m/c. - Franklin cheese dyeing m/c. - Krantz gop cheese dyeing m/c. c) Warp dyeing m/c: - Zittu beam dyeing m/c. - Ball warp dyeing m/c. - Chain warp dyeing m/c. Fabric dyeing m/c: - Jet dyeing m/c. - Jigger dyeing m/c. - Beam dyeing m/c. - Winch dyeing m/c. - High temp winch dyeing m/c. - Molten metal stand fast dyeing m/c. - Solvent dyeing m/c. - Pad dyeing m/c or Padding mangle dyeing m/c.

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a) Jet dyeing m/c: - - Special high temperature winches. - Jet dyeing m/c with additional winch. - Partially folded jet dyeing m/c. - Fully folded jet dyeing m/c. b)Jigger dyeing m/c: - Mather and Platt jigger dyeing m/c. - Closed jigger dyeing m/c. - Cyclotrac high performance jigger. c) Padding mangle dyeing m/c: - - Tow bowl padding mangle. - Three bowl padding mangle. - Fibre bowl padding mangle. - Houbold bowl padding mangle. - Zittu bowl padding mangle. According to dyeing process: 1.Open dyeing m/c process. 2.Enclosed dyeing m/c. Depending on mtl and liquor movement: 1. Mtl moves but liquor does not circulate e.g. Jigger, winch etc. 2.Liquor circulates but mtl. does not move e.g. All package dyeing m/cs. 3.Both mtl. and liquor circulate. Depending on the mtl.to be dyed: 1. Loose stock form dyeing m/c 2. Hank form dyeing m/c 3. Package form dyeing m/c 4. Fabric form dyeing m/c Fibre form : continuous loose cotton dyeing m/c: Feature: -When large amount of fibre (loose cotton) is to dyed in standard shades, continuous dyeing may be carried out. - The output of the m/c can be as high as 2000lb/hr. - Vat and Sulpher dyes are dyed on cotton fibres in m/cs

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- The cleaning of the perforated drum and the conveyors takes about a weeks time. Working principle: in the liquor. Cotton fibres are fed in the form of laps, 2'' thick and 36” wide, which are uniformly packed. The lap is passed through a squeeze rollers are fed into the m/c by conveyers belt. The method of circulati on of the dye liquor through the conveyers and the cotton lap is shown as figure. A perforated cast iron cylinder(A) which closed end plates is made to rotate at the conveyor speed. Its axis is provided by a stationary hollow pipe (B), which is connected to a suction pipe (C). Two conveyers (E1 and E2),both being continuous are made to move in contact with each other between two sets of squeezing rollers (F1 and F2) with suitable guide rollers (G1 and G2). Owing to be the cut off (D), the pump only sucks through the lower half of the cylinder. There are five unites (Wetting, Dyeing, Cold wash, Hot wash, Drying) with this type of cylinder and every unit has a definite liquor. Every units has a guide roller,two sets squeezing rollers.Five such units may be connected in series, with one common conveyer (as the lower conveyer) and five individual upper conveyers. Different operations are carried out in these five units and finally the lep is

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fed to Crightom opener, where the lap is disintegrated into loose fibres. Sequence of dyeing: Loose fibre → Lap formation → Wetting → Dyeing → Cold wash ↓ Dyed cotton ← Desintegrating ← Squeezing ← Hot wash Hussong loose cotton dyeing m/c: (Discontinuous) In this m/c the paddle or propeller is placed in the side compartment instead of at the centre. The solution rises in the side compartment and gets poured over the mtl, through which it. Perolates down and collects at the bottom compartment from where it is sucked and again forced up the side compartment. Disadvantage: -The compactly packed mtl offers considerable resistance to the flow of the liquor through the mtl and as a result uniformity of dyeing suffers. -Unevenness of packing causes channeling. Yarn dyeing Hank dyeing: Hussong hank dyeing m/c: This m/c consists of a frame carrying poles on which hanks are hung and which can when loaded by

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lowering into a dye vessel, containing the dye liquor. The dye liquor is circulated by means of an impeller, which is separated from the hanks and is located at one side of the vessel. A false bottom (grid) is provided at the bottom. The holes in the grid are arranged in such a way that there are more holes at the remote end of the impeller than adjacent to it to distribute the liquor flow uniformly. The impeller can be rotated in opposite directions alternately. The packing should be denser at ends than in the middle as the circulation of the liquor is more powerful at the ends. When the dye liquor flows top to bottom, the liquor does not come into sufficiently intimate contact with the portions of the hanks resting on the poles leading to lighter dyeing at these portions.When the liquor is circulated in the opposite direction (Upwards), the hanks are slightly lifted and this deflect does not occur.Therefore , upward direction of circulation is

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maintained during the greater portion of the dyeing cycle when the hanks are pressed into a compact mass against the perforated top of the pole frame. Package dyeing m/c: Beaumont cop dyeing m/c: Feature: 1.This m/c consist of a copper hem is pherical dye vessel provided with a tightly fitting lid. 2.The bottom of the vessel is connected to the suction end of a centrifugal pump while the delivery end of the pump is connected to one side of the dye vessel. 3. A period of 6 to 10 mins is sufficient to dye the cops. 4. Rapid circulation (25 to 50 gallon/min) takes place. 5. The m/c is simple in construction and operation and gives good results. 6. More than about 100 Ib yarn can be dyed. Principle: The cops are placed on perforated metal spindle which are inserted in a perforated metal circular plate. Another thin metal plate (Antifloater) is placed over the spindles to prevent the cops being detached from the plate. The plates, full of cops are placed in the dye vessel and rest on a flange provided for the purpose into the chambers. The pump draws the liquor under the cop the plate(lower chamber)and creates partial vacuum , which during he working of the m/c could reach 25 to 50 cm Mg. The dye liquor is then forced through the cops. The pump return the liquor to the dye vessel. Advantage:

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- Less time required. - Economical process. - Uniformity of winding is very important. - If uneven dyeing in cop dyeing, it is easy to correct since a small amount (403) of yarn is handle in each cop. - Yarn in cop form is cheaper. - Less open space is required for dyeing. Disadvantage: -If the cops are wound non uniformly, channeling takes place during the circulation of the liquor leading to uneven dyeing. Fabric dyeing m/c: Jet dyeing m/c: Feature: 1. Modern discontinuous dyeing m/c. 2. Used for woven i.e. synthetic fabric. 3. Both dye liquor and fabrics are circulated. 4. Generally of two types 1. vertical and 2. Horigontal. 5. Time is required 6-8 hrs. 6. Dyeing temp 1400c. 7. M:L ratio is 120:130. 8. M/c capacity is normally 150 kg. 9. Pressure upto 5kg/cm2 10. Jet dyeing m/c is a complete closed vessel m/c. 11. The fabric is dyed in rope form. Working principle:

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Jet dyeing m/c baised on a ventri which is a cylindrical pressure vessel and centrifugal pump rotate the liquor with the help of jet throttle. The circular movement of the liquor carries the fabric round with it in a totally enclosed tubular chamber. The ventri tube is a construction on the passage through which the speed of flow of the liquor must be increased. The primary flow is given by a centrifugal pump but it is useful to incorporate also a few inclined steam jets to boost the movement of both the fabric and liquor. Advantage: - Uniform dyeing is possible. - Knitted fabric can be dyed. - M : L ration is very small and easily adjustable. - No risk of long line. - Better dyeing is possible than other discontinuous dyeing. - Easy to maintain uniform lemp. through out the m/c. Disadvantage: - Elongation of the fabric due to the tension. - Crease of fabric may be damaged. - Discontinuous process. - Patchiness occurs due to high rate dye and for this color variation to fabric length. - Streakiness occurs due to insufficient liquor to fabric rope and for this color variation to fabric width. - Slight and dark mark is found to the fabric for relux of shrinkage fabric post processing. Jigger dyeing m/c: Features: 1. Discontinuous dying m/c.

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2. Fabric is dyed in open width in uniform tension. 3. Fabric moves but liquor does not circulate. 4. M:L is 1:7 to 1:10 5. In normal atmosphere pressure and under 1000c, fabric can be dyed. 6. Time is required 4-10 hrs for dyeing. 7. 500-1000 yds fabric can be dyed. 8. Fabric transport speed is 200-800m/hr. 9. It is used specially for woven fabrics. 10. Rollers rotate clockwise and anti clockwise. Working principle: The jigger consists of a through fitted with rollers knows as draw rollers arranged one along either side and spported in metal brearing. Guide rollers are stream line are provided in the trough. The mtl. Fabric is wound, in open width over roller standing above a shallow trough containing the dye liquor. The rollers, by rotating in clockwise and anticlockwise directions alternately , pull the fabric backward and forward through the dye liquor, completely immersion being ensured by guide rollers at the bottom of the trough. The draw roller from which the fabric is taken out is called let off roller while the other is called ‘take up’ roller. When all the fabric passes through liquor from one roller to the other the passages is called and end or one turn. A no. of ends are given, during which time the fabric

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passes to and passes through the dye solution a no. of times. The no of ends given depends on several factors, including the size of roll or batch of fabric. The time required for one end usually 10 to 15 mins and on the depth of shade being dyed. Advantage: - High speed dyeing m/c. - Low M:L ratio. - Better dye penetration. - No crease marks in fabric. - Economical dyeing process. - Used for cotton fabric specially woven fabric. Disadvantage: - Uneven dyeing in fabric selvedge. - Weak fabric may be damaged due to more tension. - Dyeing room becomes dirty and hazard. - Heat may be lost due to roller. - Fabric out of liquor in dyeing tank. - Discontinuous process. Winch dyeing m/c: Feature: 1. The fabric is immersed and pulled on from dye liquor with the help of winch and guide roller. So its named winch dyeing m/c. 2. Essentially, consists of a heated container and a revolving winch. 3. Discontinuous type dyeing m/c. 4. In the m/c fabric moves but dye liquor does not move. 5. The fabric is dyed in rope form. 6. Winch speed is 70 r.p.m and fabric moving speed 30 to 80 m/min. 7. M:L ratio 1:20 t 1:40. 8. The more speed the more dyeing. 9. Mostly fabric is kept on dye liquor during dyeing.

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10. Fabric is dyed by endless chain of the two ends of the fabric. 11. Any additional of dyes and chemicals as well as passage of steam done in the smaller compartment. Working principle: The m/c consists of a driven elliptical winch. A perforated partition dividing the vat into two compartment.Water inlet and outlet arrangements are made in small compartment and line steam can be let in the small compartment. The fabric is passed over the winch into the dye and taken over the circular guide roller at the other ends are sewn together making a long continuous loop, which is then worked in the m/c for dyeing. When the cloth is dyed in the rope form, a no or pieces can be deyed simultaneously. Dye solution is made and kept in a small compartment. Then through

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perforate partition dye liquor enters into cloth compartment. Now the fabric is circulated by winch and guide rollers and fabric become dyed. Advantage: - Easy to operate and easy to enter and let out of the fabric of the m/c. - Suitable for dyeing both woven and knitted fabric. - Due to revolving winch, fabric folding become small as a result better and level dyeing. - Dyed fabric is soft and durable. - Knitted fabric can be dyed easily due to low tension on fabric. - Many batches can be dyed at a time. Disadvantage: - Difficult to maintain uniform temperature. - Due to high liquor ratio (1:40) product cost is higher. - Elongation of fabrics occur due to tension. - Uneven dyeing due to folding. - Permanent crease many occur due to not heat set of fabric. - Labour and production cost is increase due to high temp and pressure. - More fabric cannot be dyed as beam dyeing. - Discontinuous process. Semi Continuous m/c: 1. Pad jig method. 2. Pad roll (Pad Batch) method. Pad Batch method: Basic principle : Pad batch method is a semi continuous process of cotton fabric dyeing. It takes place in two steps as below - Firstly, the fabric is padded with dye solution in the presence of an chemical solution. Then the dyed fabric are covered with polyethylene sheets and

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stored for 3-6 hrs. Secondly, After batching the fabric is rinsed and washed in open width washer. Process sequence: 1. Padding with dye and chemical solution at 200c to 300c. The temp should be kept const. to avoid variation in shade. 2. After padding, the batches the wrapped in polyethylene sheet and stored at room temp for 3-6 hrs. During storage period, the rolls may be kept slowly rotation to prevent seepage of dye liquor. 3. When the required batching time has passed, the cloth is washed in a open width washer. Pad jig method: Working principle: At first the fabric may be padded at 300c to 500c with a solution of the dye containing non-ionic surfactant. The wet padded fabric is then run on the jigger set with the required amount of the alkali and common salt. Continuous m/c: 1. Pad steam method. 2. Pad thermofix method. 3. Pad dry method. 4. Pad high temp steam. Pad steam method: Continuous dyeing of cotton fabric: Pad steam method is continuous process of cotton fabric dyeing. The method is applied in large scale fabric dyeing.

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Working principle : In this process, Fabric is dyed in open width. At first the fabric is pigment padded. Then it is passed through a drying chamber. Then it is padded with chemicals (NaOH + Hydrosulphite + Common salt) at 600c. In this stage, dye is solubilised and reduced. And after that fabric is passed through a steam chamber at 101-1020c for 8-15 sec. Finally, fabric is washed in open width washer. Thermofix method: Working principle: In this method, dye and alkali and common salt are in padding bath. Fabric is padding in the padding bath and temp. of padding bath is in room temp. Then fabric is dryer by drying and after drying, fabric is being thermofixation at 180-2200c for ½ min 1/3 min. After then fabric is washed in open width washer and prepared for after treatment polyester can be dyed in this method. Pad dry: Working principle : In this method a non volatile solvent is added to the pad bath. Urea has been found to be the most effective agent and produces marked development, especially when deep shade are dyed. This is due 1. to a lower rate of evaporation of the boiling point of water 2. to higher fabric temp. and 3. to the solvent action of urea.

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Since hot dyes are less reactive and have higher stability to alkaline solution then cold dyes. When they are dyed by this method .NaCO3 may be used as the alkali instead of NaHCO3 . Because of the lower reactivity of these dyes, pad dry process is more suitable. In addition, a short backing treatment (at 1100c to 1250c for 3 to 5 hr. is helpful in increasing the fixation. Drying system after dyeing: Textile mtls. are dried in two steps after dyeing. The steps are: -To extract excess water form mtl. Mechanically i. e. by mangling hydro-extraction suction etc. -Then the remaining water is evaporated by applying heat on mtl. The heat application methods on textile mtl. Conventional method – Hot air system. Conduction method – By heating cylinder or cone. Radiation method – In red heating. Cell drier. Advantage of package from over Hank from dyeing: -Hank reeling is a comparatively expensive and time consuming than package dyeing. -After hank dyeing the yarn must be wound on to a bobbin cone or pirn. This winding is slow and relatively costly. -Hank dyeing requires more space than that of package. -Reduce in waste. -Time consuming process. -More controllable dyeing process with better levelness of dyeing and fastness dyes are used. -Saving in water, energy, dyes, chemicals due to lower liquor ratio is used. -Less labour handling. -High temp dyeing possible.

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-Rapidly automatical process. Yarn dyeing m/c:Package form warp dyeing m/c:(Zittu beam dying m/c) Feature: This is a horizontal beam dyeing m/c Essentially consists of a cylindrical vessel provided with a hinged lid at one end. In beam dyeing m /cs, devices are provided for with drawing the dye liquor for inspection during dyeing. The liquor ratio is about 7:1 but not more than 10:1. Generally dyeing time of about 20 min. The success of beam dyeing depends on i) Thickness of the beam. ii) Yarn count. iii) Yarn twist. iv) Liquor circulating efficiency. v) Winding density vi) Cleanliness perforations. Working principle: Beam is carried on ralis and is entered into the dye vessel and when in position, the conical end of the beam makes a telescopic join with a suitable device by which the liquor can be forced in or out of the telescopic joint and dye is forced out in the yarn of beam to the perforated rails due to circulation. Circulation is done in either direction as beam will be dyed. Advantage: - Beam dye can be performed uniformly by this m/c. - After dyeing vaccum is applied and beam is sent for sizing without drying where the yarn package has to be dried before being unwind.

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Disadvantage: - More time required due to individual position for each beam. Chain warp dyeing: Principle: The warp yarn in the rope form are guided through the dye bath by immersed guide rollers, arranged in such a way that the warps pass up and down through the liquor and after leaving one unit they pass through rubber cover squeeze rollers to aid penetration and level dyeing. Finally they are received in a truck, light and medium shades can be dyed by one passage. The uniformity of shade from end-to-end of dyed warp ball varies with the difficulty of the dyeing process and depends on the skill and judgment of the dryer when feeding in the pre-dissolved dyestuffs.