It is the process by which burn off the protruded fibre from the fabric surface and get smooth fabric surface.
◆The warp and the weft yarns made up of a large number of short fibers by a process of spinning and hence tiny fiber ends are protrude from their surface and the cloth woven from such yarns has a surface from which the fiber ends protrude.
◆These fiber ends interfere with the printing of the fabric by taking up parts of fine details of a design.
◆Singeing is a process whereby fibers protruding from the normal lay of the yarns in fabric (warp and filling or course and wale) are removed by burning them off and improve the lustre and smoothness of the material.
◆Goods which are to be mercerized are also singed in order to yield maximum lustre in the fabric. Singeing is also referred to as "gassing", especially when yarn is subjected to this process.
◆The fabric to be singed should preferably be dried before singeing as wet cloth may get scorched during singeing.
◆It should not contain acid liberating substances like zinc chloride which may produce HCl on heating and tender the fabric.
Singeing machines: - Three different types of machine can achieve singeing.These are-
● Hot plate singeing machine
● Roller singeing machine
● Gas singeing machine
1. Hot plate singeing machine:-
◆In this type of singeing machine, the cloth passes over and in contact with one or two heated curved copper plates.
◆The thickness of the plates ranges from 1 to 2 inches.
◆The heating of the plates is done by a suitable burning arrangement of gas mixed with air.
◆The plates are heated to bright redness and the cloth passes over and in contact with these plates at a speed ranging from 150 to 250 yards per minute.
◆The passage of the cloth can be arranged in such a manner that one or both sides of the fabric may pass over and in contact with the heated plate(s), in order to accomplish singeing of one or both sides of the fabric in a single passage.
◆In order to avoid local cooling of a certain part of the plate(s) by constant passage of cloth over it, an automatic traversing mechanism is fitted to the machine.
◆This mechanism brings the cloth into contact with a constantly changing part of a plate not only to avoid local pulling but also local wearing of a plate.
2. Roller singeing machine:-
◆In this type of singeing machine, the cloth passes over and in contact with a heated rotary cylinder made of copper or cast iron.
◆The rotary cylinder has internal firing and revolves slowly so that constantly a fresh surface of the roller comes in contact with the cloth.
◆The direction of rotation of the cylinder is opposite to the direction of the fabric so that the protruding fibers or nap of the fabric is raised.
◆This type of machine is particularly suitable for the singeing of velvets and other pile fabrics.
◆If the singeing of both sides of the fabric is required, then two cylinder are employed one for each side of the fabric.
3. Gas singeing machine:-
◆In this method, gas burners are used to singe one or both sides of the fabric during a single passage of the cloth over the flames.
◆The machine is provided with two gas burners supplied with a mixture of coal gas and air under pressure.
◆The width of the sets of burners can be adjusted to suit the width of the fabric, the length of the flame and hence the intensity of heat can also be adjusted.
◆Generally singeing is done on two burner gas singeing machine because in this machine more uniform singeing is obtained and ends present in the Interstices of the warp and weft can be also singed.
◆The cloth in the open width is passed at high speed (50 to 100 mtr/min.) over a flame (temperature of the flame is too high around 1300°C), when the fiber ends are burnt off (singed), leaving a smooth and uniform surface of the fabric.
◆By using two flames both the sides of the fabric can be singed by passing the fabric through the machine only once.
◆The fabric is then dipped in water to extinguish any residual sparks, squeezed between two rollers plaited.
◆The machine is provided with two gas burners supplied with a mixture of coal gas and air under pressure.
◆Using suitable rollers (called guide rollers) a slanting loop of the runnning cloth is formed and the flame is allowed to enter the loop space at an angle so that the flame grazes over the fabric surface.
◆In the actual operation of the singeing machine, the machine is first threaded with the cloth, the machine run at full speed and then the gas is ignited.
◆When most of the cloth is singed, the burner is first put off and then the machine is stopped.
◆This sequence is necessary to prevent the fabric from catching fire.
◆In order to remove the burnt fibers and exhausted smoke, sparks, fumes, a hood and exhaust fan are provided over the singing machine.
◆The singing room is separated from other department in the mill.
Passage of Fabric on Singeing Machine:- Trolley > Guider > Brushing unit > First Burner > Second Burner Quenching Chamber > Platter > Trolley
Main parts of singeing machine:-
●Tensioning device
●Brushing units
●Burner
●Quenching chamber
●Exhaust fan
Functions of parts:-
1. Tension Roller:- It gives the tension and removes creases from the fabric.
2. Brushing Roller:- It has set of brushing roller to remove loose thread dust, dirt and metal particles and deliver these impurities to the dust bag. Spacing between these rollers can be adjusted depending upon the thickness of the fabric.
3. Burner:- Set of the burner is used for burning the protruding fibers. The width of burner can be adjusted according to the fabric width.
4. Exhaust Fan:- It sucks the burning fiber and smoke and transferred to outside the process house.
5. Cooling Roller:- The water cooled rollers are used to cool the fabric coming out from 5. the flame, thus avoiding the change of sticking the fabric on the roller and prevents it from becomes harsh.
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