Safety in textile Industry
The raw material used in the Textile industry is cotton and synthetic fibres or yarns, dyes and chemicals. These are the synthetic yarns may be mono filament or multifilament depending upon end Use. The chemicals used in the process house are of hazardous nature like dyes, acids solvents etc. the manufacturing process involves hazardous machine operations and use of pressure vassals at various stages like mixing, blow-room, carding, sizing and weaving. Humid atmosphere is basic requirement of manufacturing process in spinning and weaving parts of an industry. The humidity ranges from 70% to 85% the work environment is polluted due to dust, floating fibers noise as well as due to chemicals fumes. The industry is having many health hazards. Byssionosis is the modifiable disease of textile industry under factories Act.
The prominent hazards:
- Polluted Work Environment.
- Fire various hazards involved in the machine operations.
- Chemical splashing, fumes and exothermic reactions.
- Flying objects.
- Material and chemical handling.
Composite Unit of a Textile industry generally consists of four Parts:
- PROCESS HOUSE
The main purpose of spinning section is to manufacture yarn from the fibers. The step by step manufacturing process is as detailed below.
In this activity bales of the cotton fiber or synthetic fiber are opened and mixed together to get the suitable product.
In this activity cotton and synthetic lumps are further opened and cleaned. The trash, dust and seeds separated from the fiber dropped down the Cellar room situated below the blow room line.
In this process the lap prepared in blow room is feed to the card machine and processed. On this machine every single fiber separated from each other by wire points mounted on Cylinder and Doffer. Any impurities like dust, foreign particles, broken leafs are removed and web like structure is formed. This web is collected at the centre in the form of silver and collected in to the cans.
Silver prepared in carding process having fiber laid down haphazardly in any direction. Such silver does not give quality yarn. These fibers are pulled in the drafting rollers of the draw frame and brought parallel to the axis of the silver. If one passages are given.
The other purpose of this operation is to blend the cotton and synthetic material. The number of silvers of both the material are feed to the draw frame in the requisite proportion and drafted to mix tog ether. One passage of drafting process does not give homogeneous mixture or proper blend. hence normally three passages are given.
This process is for cotton only. In the cotton all fibers are not of same length, some are short length; some are medium and longer length. Presence of the short fiber affects on the quality and :Strength of final yarn produced. Hence for removing these short length fibers a lap is prepared out of 16 to 20 silvers on lap former machine and feed to the comber. During combing operation short length fibers are removed and other fibers are made parallel to each other and collected in the form of silver. Supper fine, even and high strength yarn is produced from this combed material.
Fly frame or Roving:
The purpose of fly frame operation is to reduce the diameter of carded or combed silver considerably to suit to the final Spinning process. The silver fed to the fly frame is drafted in the drafting zone to reduce the diameter and twisted to some extent to make it compact. These rove wound on bobbins.
This is the operation in which actual yarn of required count and twisted is produced. Roving bobbins are fed to ring spinning machine. The rove is drafted in drafting zone in the proportion of count of out coming yarn.
Count of yarn = Number of Units of 840 Yards per Lb.
On ring spinning machine yarn is wound either on warp bobbins depends upon its further use. Weft bobbins are used in loom shed as ready package of weft. Cheeses and cones are prepared out of warp bobbins to use in warping operation for preparation of beams.
Warp = Yarn in the fabric along the length of fabric.
Weft = Yarn in the fabric along the width of fabric.
Doubling operation is same in nature as of spinning. In this process yarn is doubled and wound in the form of cheeses or cones and used to produce weft pirns or beams.
In weaving section fabric is manufactured on loom for which warp beam and weft package is required. These warp beams and weft packages are prepared in weaving preparatory. The process flow is as mentioned below.
Weft pirn to be used in loom shed as per required diameter and length of package are produced on pirn winding machines. The bare bobbins are made up of wood or plastic. The density of yarn wound on the bare pirn is maintained by providing tension on the yarn to be wound on the yarn. Similarly any fault in the yarn like knot, weak places are removed during winding process.
In this process yarn from warp bobbins are wound in the form if cheese or cones on Auto corner or Barber colmen machines. While winding yarn faults are removed and desired density of package is maintained by giving tension on the yarn being wound.
The cheeses prepared in the earlier process are mounted on the creel of warping machine. The total numbers of cheeses are equal to the number of ends desired on the beam. The all ends from the cheeses are collected in the form of sheet and wound on the beam. When sizing is not required to the warp beam to be used in loom shed then this warp beam goes to the drawing in section, else to the sizing.
During weaving process warps ends of the beam under goes various tension and abrasion. To with stand these tension and abrasion size paste is applied on warp ends such that those will become hard and flexible. The ingredients of size pest are -Starch, antistatic, agent, anti fungal agent, smoothening and hardener agent. The viscosity of size pest is maintained as per requirement of size take-up by warp sheet. The warp sheet is passed through size box and squeezed in the squeezing rollers to remove excess pest on warp sheet. T his warp sheet is then dried on the range of drying cylinders and wound on beam which is known as weavers beam.
The ends of the weavers beam are drawn the held eye and reed dent and made ready to fix on loom.
During weaving cloth is weaved on the loom. Various looms like over pick loom, under pick loom, Auto loom and unconventional looms like Air jet, Water jet, Sulzer looms are used for the purpose of woven designs in the fabric some attachments like Dobby Jacquard are attached to the loom.
Cloth produced in the loom shed is gray cloth. Itis inspected for defects and if any are removed from the fabric. The inspected fabric is send to the process house for process house treatments.
in process house gray cloth under goes various processes, these processes varies depends upon final product. The objective of these processes and chemicals used are as mentioned below.
Size applied during sizing process as far a possible does not become part of finished product, hence de sizing is done by gray cloth by dilute solution of HCL or H2SO4 Acid.
This process is also known as Caustic Soda treatment. During de sizing process oil and fat material is not removed completely the presence of such material affects on finish of the fabric. Caustic soda converts fat material in soluble matters and removed from the cloth by dissolving soluble matters in waters.
This process is mainly applied to synthetic and blends fabrics. In this process fabric is passed through hot chamber and allowed to shrink.
The purpose of this process is to increase the whiteness of fabric. The fabric is treated J-box or kier under presses. For cotton fabric bleaching agent used is sodium hypo chloride and that for synthetic and blend fabric hydrogen peroxide.
Mercerizing treatment of 20% caustic soda is given to cotton fabric only, for the two purpose mainly
To give extra Whiteness to the fabric
To increase dye uptake quality of fabric
In this process colour is applied on the fabric. The limitation of this process is only one colour can be applied and part of fabric cannot be dyed. The machine such as jet dyeing. Gigger dyeing are used for the purpose.
In printing process various types of designs can be printed on fabric and multiple colours can be used. The dyes used for the purpose are disperse dyes, vat dyes, reactive dyes, pigment dyes etc, where as the machines used for the purpose are rotary printing, flat belt, padding etc.
After the fabric is printed to fix the colour permanently it is heated at a temp. Of 1500c to 1800c in a closed chamber for certain time. This process is also known as colour fixation process.
Once the ageing process is complete fabric is washed in the dilute solution of Sodium hyposulphite and Caustic soda to remove the excess dye on it.
This process is used only if the cotton content of blend fabric is to be removed and only synthetic part is to be maintained. For the purpose fabric is passed through the 70% H2s04 solution. Cotton dissolves in this solution but not synthetic material.
Finishing is given to the processed cloth by two ways
1) Mechanical finishing
2) Chemical finishing
For mechanical finishing Sanforising or Minifelt machines are used. On this machine cylinder is heated by steam at a pressure on 2.5 to 4 lb/in. the wooden or rubber blanket which ultimately gets heated by cylinder. In chemical finishing machine used is Slenler. Fabric is passed through the chemical solution and heated in the chamber. On this machine width of the fabric also can be adjusted.
Finished fabric is checked for any defects and packed as per market requirement.
HAZARDS AND PREVENTTVE NIEASUREES IN TEXTILE INDUSTRY
The work environment in textile industry is dusty, the total dust and the fiber dust are two aspects for consideration.
The dusty sections of the mill are the Mixing, Blow room, carding, Combing, Fly frame, Ring frame and some extent winding section. In the mixing and blow room heavy dust is accumulated in the cellar room or it is deposited on cyclone separators. In carding section the dust generation sources are near licker in cylinder, doffer, flats etc. Exposure to the dust is severe while carrying out stripping operations and collection of licker in droppings. Individual dust extraction devices or a centralized extraction system, picking up dust from dust generating sources are standard methods of dust collection. The modern cards are totally enclosed and eliminates the dust exposure in the said area. Provision of dust extraction system at the sources as above will help reduce dusty atmosphere. It is desirable to accumulate dust in dust bags and dispose them at suitable intervals. It is better to use vacuum cleaners because any other method like blowing, only displaces dust from one place to other and dose not dispose it off.The other sections of spinning process like Comber. Fly frame, Ring frame the floating fibers in the work environment exists. To make these floating fibers settle on floor plenum Ventilation is effective type of ventilation. Use of dust mask is effective way of protection against dust.
As per Factories act and ACGIH, prescribed maximum permissible exposure limit of total dust is 1mg/m3 and for cotton fibers dust (fiber with less than 15 * 10-2 length) is 0.2 mg/m for eight hours work. Inhalation of cotton dust results in chest tightness, breathlessness and the alike known as BYSSIONOSIS, which is a notifiable disease under factories act This calls for measures such as pre employment and periodical medical examination. Such examination could help in quick shifting of affected personnel in other work areas for recovery from adverse health effect. Apart from this constant monitoring and adoption of centre measures is a must.
The Noise level in Ring spinning operations and every type of looms including Air Jet is higher than prescribed limits under Factories act and Environment protection act 90 dB(A) and 75 dB(A) respectively. The general methods of contending such high level is of noise is at source path or at the receiver. At scarce steps like arresting vibrations reducing frictional noise by using friction bearing with continuous lubrication to ring spindles and use of nylon gear wheels can be adopted. Acoustic encloses for buffer are also for consideration. Use of sound absorbing materials absorbing materials may not be practicable as the high humidity and fiber fly would accumulate on such materials and making it effective. Use of ear defenders such as earmuff and earplugs by personnel exposed to these high noise levels must be ensured.
The presence of combustible and flammable materials in large quantity is there in all sections of textile industry hence any source of ignition can put whole unit at uncontrolled fire. Hence below mentioned precautions should be adhered to.
- The go down where cotton bales are stacked should be well ventilated so that the hoop iron do not impart and generate sparks as a source of ignition. it is also to be kept in mind that any broken glass pane on windows with its sharp edge form a prismatic effect converging sun rays on to cotton bales arid could be a source of ignition. The direct sunlight falling on bales could lead to spontaneous ignition.
- Use of naked flames for soldering or welding on shop floor should be under permit and supervision.
- Lamps used to prevent lapping or warning up could ignite fibers accumulated over it and latter setting it to fly around will also be source of ignition.
- Mechanical friction with the availability of dripping lubricating oil and loose fiber could initiate a tire. Oiling should be done after ensuring that the oil holes are clear and the oil is reaching the part being lubricated.
- The electrical panels, switchboards and other electrical equipment’s are also accumulated with dust and needs attention, wherever needed those should be flameproof.
- Processing of fibers and fabric are like to accumulate static charges should be carried out under effective grounding bonding and antistatic controls prevent accumulation of static charge.
- Singing machines should be invariably be provided with a solenoid valve on the fuel line to arrest the fuel supply, it the event of an electrical failure. This prevents the stationary fabric undergoing singing from being ignited.
- It is desirable to store freshly dyed fabrics in isolation as they could ignite due to spontaneous ignition.
- The standard practices should be followed in handling and storage of chemicals used in process house.
Process House Hazards:
HANDLING OF CHEMICALS:
The processing of textile generally involve dilute acids, alkalis, solvents, dyes and bleach liquors like chlorine, hydrogen peroxide.
Generally the concentration of the process liquid dose not exceeds safe concentration levels. However the bulk of the chemicals received are of the higher concentration and precautions in respect of storing them in compatible containers must be complied with. In case of chlorine a better practice is to store minimum quantities of it on in work room. Care also should be taken that proper equipments and systems are readily available to handle any emergencies like leak The outlet from storage vassals of acids and alkalis and the piping should resist corrosion.
It is advisable the dyes are handled with care while preparing liquors and pastes. The solvent used for printing which are highly volatile should be stored away from process zone and the quantities brought in for use should be the minimum the storage areas of fuel oil for boilers etc need to fulfill statutory requirements as applicable to bulk storage. The supply of safety data sheet in respect of substance handled should be made available to the personnel handling them.
Use of appropriate mask, chemical glove, apron and safety shoes should be adhere to.
Processing and Finishing:
Effective exhaust draught system should be ensured to avoid air pollution in work area.
In the polymerizing range it is absolutely necessary to provide an interlocking device to ensure that the exhaust fans are on before any fabric is fed into the chamber. This helps in preventing the volatile carrier accumulating which could lead to a explosive situation. It would be far better to dry out the fabric outside the chamber to eliminate most of the volatile solvent before the fabric enters the chamber. This reduces the quantum of the volatile solvent available in the chamber.
In the shearing and cropping machine the exposed rotating cutters can be covered using transparent cover. Many of the machines in the process house generally have nip hazard. They could be calendars, washers, printing machines etc. Many of these nips could be guarded by means of nip bars. The provision of audio signals to warn workers working near the calendars, drying ranges, stenters etc. could help in preventing entanglement and drag of it inattentive operators along with the fabric in process.
Machine Related Hazards:
SPINNING: In machine related hazards there are number of nip points which are left unguarded. These points could be identified as the feed and calendars rollers of the blow room machinery, carding machines, combers and drafting zones of all frames (draw, inter, flyer and ring). Many a time arguments are put up to say that any guard attempted at such point would interface in to the working of the rollers. But it is, at least possible to provide mesh cover with interlock on some of the rollers in the blow room machinery
Drafting zone on the draw frame could be covered with total enclosures are well interlock to stop the machine when enclosure are open.
Weighs 450gm to 850gm and is to fly from one to other end on a loom, could fly out of its parts for varies reasons. The shuttle guard provided on the loom does not really prevents a shuttle from flying out of the loom, but it only helps in arresting the shuttle’s tendency to lift upward and shoot out to heights. Thus to keep a check on the direction of shuttle flying out, a shuttle guard is provided. This hazard is absent in non-conventional shuttle less loom.
Use of pressure vessels (Unfired):
It is necessary to consider the sizing Cylinders, kiers and to some extent calendar and drying range as pressure vassals though the pressure ranges are not very significant all tests and examinations are to be carried out ensure their safe performance It is essential that the siphoning systems on the cylinders are maintained well to deliver out the water condense and prevent any damage of this cylinders. It is also required to maintain the vacuum breakers provided to prevent any cylinder collapse. All instrumentation and safety gadgets must be examined periodically for their reliability. Air compressor is also very required pressure vassals in textile industry. The misuse of compressed air for personal cleaning must be avoided.