FIELD OF INVENTION
The present application relates to mechanical processing of silk varus through splicing and surface modification. BACKGROUND OF THE INVENTION
Silk the queen of textile is the symbol of luxury, elegance, class and comfort and alwavs loved by quality conscious people throughout the world. India is the second largest producer of silk with 17.550MT (2001-2002) of production and also the largest consumer in the world. The main problem faced by the Indian silk industry during mechanical processing is end breakages in doubling, twisting, winding and weaving etc. These end breakages affect the production efficiency in the above processes and also it deteriorates the quality of the final product.
The end breakages are caused due to the denier variation, poor quality knotting (Rajkumar R, Silk knitted fabrics for outer garments, The Indian Textile journal, 2001, 111, 127-134) and improper packaging of yarn etc. Each and every end breakages further leads to a knot. This is one of the main reasons that Indian silks are not used for knitting. During knitting these knots lead lu breakages of needier if the thickness and the lail ends of knot arc tnoie.
Till today, Indian silk industries are using manual knotting method. Each knot leads to a thick place. This problem starts from the stage of reeling since at that time of breakages of filaments, piecing of the filaments is done by the operator in the wet state itself. Further, during winding the yarn breakages are repaired by weaver's knot. The yarn joint obtained by the knotting method constitutes a lump shaped projection. Thus, disadvantageous!}-, when this yarn is used for fabric production, the lump shaped projection must be pushed into a cloth so as to project from its back side.
Some silk industries were surveyed before working on this problem and it was observed that even use of latest technology shutde less looms like rapier may not prove beneficial due to poor quality of raw material. Just like Ilandloom, there was one operator for each loom in a particular factory that was sun-eyed and even then the frequency of loom stoppages was very-high. There was loom stoppage due to end breakage at every 15 minutes interval. This highlights the low quality of the silk yarn used in the industry.
The present invention resides in an evaluation of splicing as a means of solving the problem associated with knots. A spliced joint is much smaller than a knot and it is usually around 80-90% as strong and 1.1 to 1.2 times as thick as the parent yarn. However, a raw silk yarn is an assembly of filaments joined together by the gum sericin. Splicing such a yarn would involve opening up the individual filaments by some means before intermingling or interwining them. Splicing may overcome the problems that arise from the presence of knots. Compared with knots, splices may help to reduce possible holes in knitted fabrics, the amount of warp

breakage at the reed when fabrics with high warp densities arc woven, and varn breakage at the turning angle of the yarn. Overall production efficiency can be thus increased.
There are different methods of splicing means for different tvpes of varus as described.
Mechanical splicing is performed by bringing together the yarn ends to be joint closelv adjacent
and parallel with the help of a mechanical splicer. Shear, tensile and compressive forces are
applied on part of the circumference of each yarn to be joined by physical contact with moving
deformation elements. The original cross-sections and the structure of the varn ends are
modified by this, while at the same time individual fibres are detached in part from the fibre
-assembly at the join and displaced to wrap the yarn ends securely within the range of
deformation elements. This gives durability to the joint (Talukdar M K, Modern developments in
Winding, NCVTE Yarn Winding, Ed by Banerjee P K, Alagirusamy, 37-50; Rohner J, Theory and
practice of splicing, Melliand Textilberichte fling. Ed], 1984, 284-286; Sengupta S, Knotless joining
of Spun Yarn, Man-Made Textiles in India, 1998, 169-176 and Bissmann (), Knotfree yarn joints
by splicing, International Textile Bulletin, 1981, 3, 281-289). The limitations of mechanical splicer
are: jam opening is incomplete because of irregular twihl distiibutiun in die \arn. It is Muitab'i-
for short fibres to produce a definite pull- apart point. Because longer the staple, the more will
the position of separation van*, with a negative effect on the wrap. The method is elaborate,
since different opening and twisting wheels arc required in close quarters, corresponding to fibre
length. Also the adjustment effort is high, since untwisting and retwisting must be adjusted to the
respective yarn twist. Splicing is not possible for ply yarns, since they cannot be opened by
twisting. Lot of maintenance and care is needed because of penetrating dust and fibres.
Electrostatic splicing is performed by untwisting the yarn ends and spreading the fibres of opened up ends in umbrella form in an electrostatic field. They are then intermingled and closed by reversal of the field. Simultaneously, twist is inserted in the direction of yarn twist. The splices are hardly recognizable visually and their strength is estimated to be 80-85% that of the basic yarn. Theoretically this splicing system produces an ideal splice, as it alone produces an ideal fibre mixture (Talukdar M K, Modern developments in Winding, NCVTE Yarn Winding, Ed by Banerjee P K, Alagirusamy, 37-50; Rohner J, Theorj' and practice of splicing, Melliand Textilberichte [Eng. Ed], 1984, 284-286; Sengupta S, Knotless joining of Spun Yarn, Man-Made Textiles in India, 1998, 169-176 and Bissmann O, Knotfree yarn joints by splicing, International Textile Bulletin, 1981, 3, 281-289). However, with an electrostatic splicer, opening and separating of yarn in the electrostatic field is not possible at a definite position. It is difficult to merge the umbrella shapes together for large number of fibres in the cross-section (as they go their own way). Plied yarns cannot be spliced as they cannot be opened by untwisting. Splicing time is too

long. A high volragc and"its control is required to create the electrostatic field! Influence of ambient temperature on the electrostatic effect is another factor to be considered.
Thermal splicing is performed by heating up rhe air for splicing at the splicing head. This makes the fibres more pliant and therefore can be more effectively intermingle. This technique is generally used for splicing of wool and wool blends as the temperature of the splicing air is adapted exactly to the properties of the animal fibres to be spliced. Due to localized heating in the splicing zone, thermoplastic properties of fibres can be used for safe fixing of the yarn structure in the zone of the spliced joint and a correspondingly higher tensile strength of the splice (Talukdar M K, Modern developments in Winding, NCUTE Yarn Winding, Ed by Bancrjee _P K, Alagirusamy, 37-50 and Manual of Schlaforst Autoconer 338, Schlaforst). The limitation of such a splicing is change in dye take-up in the splicing zones.
Pneumatic or air-splicing is performed with the help of both aerodynamic and mechanical forces to open as well as join the yarn ends together. The yam ends to be joined must be placed in the splicing chamber. This is simplified by providing the chamber with a hinged cover (or lid), which is normally open. When the cover is closed, an air jet is introduced into the splicing chamber at very high speed. The jet is highly turbulent, and the violent small scale disturbances radically disturb the fibre arrangement of the yarn ends in the splicing chamber. Those fibres lying across the air-inlet opening are direcdy subjected to the whirling action of the helically rotating air-jet flow, which leads to twisting and intermingling of the yarn ends (Jianheng Z, Pengfei Q, Air flow in a Pneumatic splicer by CFD, Textile Research Journal, -2005, 75, 106-110; Lam H L L, Cheng K P S, Pneumatic sphcing, Textile Asia. 1997, 66-69 and Cheng K P S, Chan K K , How, Lam H L L, Spliced yarn Qualities, Textile Asia, 1997, 45-47).
Injection splicing is performed by adding water to the splice through an injection device. Optimum process sequences and high quality- of the splices can be made, as it increases the splice strength of vegetable fibres. Along with this, minimal soiling of the splicer and its surroundings can be achieved. The Injection- Splicer is particularly useful in the winding of bast fibres and hard fibres, compact yams, coarse cotton yarns, OE-rotor yarns and plied yarns (Talukdar M K, Modern developments in Winding, NCUTE Yarn Winding, Ed by Banerjee P K, Alagirusamy, 37-50 and Manual of Schlaforst Autoconer 338, Schlaforst).
There is need for an effective splicing process to splice silk yarns and overcome problems that arise from the presence of knots in silk yarn. The quality' of the spliced yarn can be influenced by pressure of the fluid, duration of blast, splicing length, yarn twist, yam count, spinning method and design of the splicing chamber. Considering all the factors a new splicing process using a novel apparatus is devised.

A yarn which is being knitted or woven into a fabric or wound onto a package runs around many guides during the process. Bach one causes a drag on the yarn due to friction. Change in the frictional properties of the yarn due to friction. Change in the frictional properties of the yarn cause an increase or decrease in the drag and hence the tension in the yarn. This give rise to problems such that, too much or too little yarn is fed to a process or the yarn is too tight or too slack. Hence the frictional properties of a yarn are important for its smooth running on production machinery (Saville B P., Physical testing of textiles. Woodhead Publishing Limited, 1999). Because the frictional properties of yarns will affect the performance and life of varn guides, knitting needles and other contact surfaces, the modifying effect of surface finishes and lubricants are of special interest. Frictional properties also affect the quality and performance properties of yarns and subsequently of products made from them (ASTMD 3108, Coefficient of friction yarn to solid material).
Silk fibers have a very irregular surface structure mostly in sericin layer, which constitutes of traverse fissures, creases, folds and uneven lumps. This attributes, to the gummed silk filament too little elasticity for knitting; its tenacity also is insufficient. Knitting with classical latch needle knitting machines requires a higher elasticity for the loop forming process, as on bearded needles. Knitting machines with many feeders produces fabrics with much barre, and seldom reached a higher efficiency than 20° o. Surface modification using a suitable lubricant can overcome the above mentioned problems. The present invention relates to mechanical processing of silk yarns bv splicing using a novel process and apparatus and surface modification by changing the co-efficient of friction of the silk yarn. -OBJECTS OF THE INVENTION
The object of the present invention is to improve mechanical processing of silk yarns through splicing and surface modification thus providing a better quality silk product.
Another object of the present invention is to get through the problems of end breakages of silk filament during mechanical processing. EMBODIMENTS OF THE INVENTION
The present invention provides improved mechanical processing of silk yarns through splicing and surface modification thus providing a better quality silk product.
In an embodiment mulberry silk filament yarns are spliced with a hand held splicer. In another embodiment splicing of silk yarn is done with a mixture of steam and air. In another embodiment splicer prisms are used in splicer. In another embodiment, the frictional properties of the yarn are changed. In a further embodiment lowering of co-efficient of friction is done by means of lubrication of raw undegummed silk filament yarn.

BRIEF DESCRIPTION OF DRAWINGS
Fig 1 is a graphical representation of linear density vs width of silk varus Fig 2 shows mass evenness of mulberry silk varns Fig. 3.1(a) shows side elevation view of the Hand held Splicer Fig.3.1(b) shows top plan view of the Hand held Splicer
Fig. 3.2 (a), (b), (c), (d) illustrates sequential working stages of the I land held Splicer Fig 4 is a microscopic image of S3 after subjecting S3 to the blast of air Fig 5 is a microscopic image of S4 after subjecting S4 to the blast of air Fig 6 is a microscopic images of S5 after subjecting S5 to the blast of air Fig 7 shows yarn samples spliced with steam Fig 8 shows valves used in the set up for splicing of silk yarn Fig 9 shows a hand held splicer used for splicing of silk yarn
Fig 10 shows a process sequence for splicing of silk varn through hand held splicer Fig 11 shows spliced yarn samples after splicing with steam and air Fig 12 shows spliced yarn samples at 2.5 bar sieam pressure viewed under microscope Fig 13 shows spliced yarn samples at 4 bar steam pressure viewed under microscope Fig 14 is a surface plot of pressure of mixture vs. pressure of air and steam Fig 15 gives a relation between pressure and temperature of mixture and pressure of air and steam
Fig 16 is the front, top and side view of Splicer prisms DZ1 and DZ3 used in Autoconer Fig 17 is the front, top and side view of Splicer prisms DS1 and DS3 used in Autoconer Fig 18 is the front, top and side view of Splicer prisms DZ1/16.1E and DZ3/16.1E used in Autoconer
Fig 19 is a yarn friction measuring apparatus DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to mechanical processing of silk yarns through splicing and surface modification thus providing a better quality silk product. The various embodiments of the invention are described by way of tables and figures. Yarns taken for experimental evaluation are in the form of skeins commercially available in the market, sourced from different Indian places like Malda, Murshidabad, Bangalore and China. Yarn available in the market is in the form of skeins having a circumference of 57 inch as opposed to the cotton hanks of circumference 54 inch. So a suitable hank winding machine is required for converting the hanks to bobbin. This operation has been carried out at the Nath Bros Exim International Ltd., a private company -located at Noida. Here the hanks were first converted to double flanged bobbins at the rate of 250m/min. After this, these bobbins were converted to cones on cone winding machine.

Physical Properties of yarn samples
The yarns were tested for mechanical properties and structural characteristics for _evaluating the difference in the mechanical properties of the varus procured from different sources. The tests were carried out as per standards listed in Table 1.
Table 1 Standards used for testing Physical properties of yarns
(Table Removed)

Table 2 shows physical characteristics of experimental yarn samples. All the yam samples were without twist except sample S4 and S7 i.e. Bivoltine mulbcrn-. Width of the yarn increases with increase in linear density as shown in Fig 1. The regression equation reveals that density of -different yarns differs, owing probably to their different origins. The number of baves in yarn cross-section, is in the range between 18 to 110. The linear density of the baves is lowest for S7 (0.92), which might be because S7 is degummed silk. Due to removal of sericin from the baves, which constitutes about 25° o of the total mass, the linear density has gone down.
Table 2 Yarn Physical characteristics
(Table Removed)

Yarns were evaluated for their mechanical properties on Instron -1201 interfered with a computer using 50 cm gauge length and l00mm/min cross-head speed. Yarns were threaded between the jaws at a tension level of 0.01N/tex. A minimum of thirty tests were carried out per sample and the average and CY values were calculated. Table 3 shows the mechanical properties of yarn. Sample S7 shows the highest tenacity. Mulberry yarns are arranged according to their tenacity values in the following order: S7>S5>S6>S4>S8>S1>S2>S3. It was seen that China undegummed mulberry (S8) shows less tenacity than Bivoltines (S5 and S4) and even multivoltine from West Bengal (86). Both Chinese varieties exhibit very low strength CY%(4-5.6%). Bengal bivoltines are comparable to the Chinese yarns (4.6S3>S2>S8>S5>S6>S4>S7 as shown in Fig 2
Bivoltines S2, S4 and S5 arc found to be free of thin places along with both Chinese yarns S7 and S8. Majority of the thin places are found in S1 (multivoltine) followed by S3 (crossbreed) and then S6 (multivoltine). The low stength of S3 (crossbreed) can be contributed to the thin places which account for 74.11% of the total imperfections, while in case o SI and S6 (multivoltines), the thin places account to 50.4% and 12.5% respectively. These thin places are probably due to poor practices in reeling.
It is seen from Table 4 that neps contribute significantly to the imperfections. These neps account for approximately 47% to 80% of the total imperfections. In this case neps accounted for around 18%, while for the Bivoltines S2, S4 and S5, the neps accounted to be 80.2%, 50% and 83.3% respectively. Multivoltines SI and S6 have accounted 47.16% and 62.5% respectively for the neps out of the total imperfections. Chinese yarns are also not far away regarding neps. They accounted for 76.9% (S7) and 61.5% (S8) respectively. These neps are major source of concern during knitting, so if one can get through them then the quality of the knitted end product as well as the process can be improved. One interesting point has been noted that thick places are least for SI (Multivoltine) followed by S3 (crossbreed). They arc respectively 2.4% and 7.05% for SI and S3. Thick places accounted %0% for S4 (Bivoltine) followed by S8 (38%, Chinese), s6 (25% Multivoltine), S7 (23% Chinese dyed), S2 (19.5%, Bivoltine), S5 (16.5% Bivoltine) out of the total imperfections. These thick places can cause needle breakages during knitting of the yarn so should be avoided through careful reeling.
S5 (Bivoltine) and S6 (Multivoltine) varieties have CV% lower than S8 (Chinese), but the total number of imperfections are more than that of S8. These imperfections cause loss of process efficiency during weaving and knitting due to frequent stoppages. The quality of the end

product suffers because of these imperfections. These imperfections arc due to poor reeling
practices prevalent in India, which is improved enable India to complete with Chinese Silk. Table 4 Evenness and imperfection values of Mulberry silk yarn
(Table Removed)

Splicing of silk filament yarns by hand held splicer:
Splicing of mulberrj' silk filament yarn was basically aimed to get through the problems of end breakages of silk filament during mechanical processing. A novel process of splicing using a hand held splicer was developed.
The hand held splicer used in the laboratory for experimental purpose consisted of a timing resen'oir composed by a number of spaces interconnected with each other and communicating with the fibre blending chamber, a cut-off valve controlling the flow of air from the air source to the blending chamber. An auxiliary throttling means adjusts the flow of compressed air from the timing reservoir to the blending chamber with desired accuracy, so that
it can be possible to select the proper timing of jet duration according to \arn tvpes. The working of the splicer can be explained in details with the help of l;ig 3.1 and Jig 3.2.
The splicer shown in the Figures can be manually controller by a trigger and is intended to be worn on the hand of the operator. The splicer is connected to the compressed air source through a tube (12). In the inoperative position Fig 3.9(a) the cut off valve (30) is closed and the cut off member (37) allows a free flow from the channel (28) lo the outlet duct (26). 'The compressed air coming from the tube (12) into the inlet duct (25) is thus arrested in the portion of the channel (28) upstream of the valve (30).
When, after positioning the two yarns to be spliced in the blending chamber (20), the presser (24) is actuated by the trigger (23) to bear against the head (34) of the stem (31-32) of the valve (30) against the bias of the spring (36), the valve (30) is opened (Fig 3.9(b)) and the compressed air reaches virtually instantaneously through the channel and the (28) and the outlet duct (26), the chamber (20) to carry out the splicing operation. Simultaneously, the air flows through the passageway 51 and reaches the several spaces of the liming reservoir.
The rime which is required for filling the reservoir and establishing therein such a pressure as to overcome the bias of the spring (43) and thus to shift the moveable wall (40) and the cut off member (37), its cylindrical body (38) becomes inserted into the seat (39) and thus cuts off the air flow in the oudet duct (26) and the blending chamber (20) (Fig 3.2(c))
On completion of a working cycle, as the presser (24) is released, the spring (36) brings "back the cutoff valve (30) to the closed position (Fig 3.2 (d)) and its stem section (32) clears the bores (57, 58) so that the air can be discharged from the reservoir (41, 48, 49 and 50), through the axial bore (33) of the stem (31, 32) and through the perforations (35) of the stem (34). These perforations (35) are appropriately oriented so as Lo clear the device from residues of fibrils which may be accumulated during operation. As the air being discharged from the reservoir 41, 48, 49 and 50, the pressure therein is decreased and the spring 43 can restore the moveable wall 40 and its associated cut off member 37 to the starring position.
The yams having a short and soft fibre require shorter durations of the jet, whereas yams having a long and coarse fibre structure require longer duration of the jet. Too long a duration of the jet on yarns having a short and soft fibre structure may originate an undesirable weakening of the fibres, whereas too short times in the case of yarns having a long and coarse fibre could not afford to ensure a satisfactory blending. [31] Parts of the hand held splicer
10. Main body of the splicer 38. Cylindrical body (axially displaceable)
11. Strap for hand wearing 39. Seat
12. Tube ro be connected ro the fluid source 40. Moveable wall
13. & 14. side wall 41. Cylindrical space
15. Shielding stirrup 42. Fixed wall
20. Blending chamber 43. Spring
21. Block 44. Piston

23. Trigger 45. Gasket
24. Presser member 46. Front protrusion (acting as a spacer
between the wall 47 and the volume 41 opposite to the wall 42)
25. Inlet duct for compressed air (tube 12 is 47. Wall connected to it)
26. Outlet duct (directly communicates with 48. Space central port 27)
27. Central port (opens into the blending 49. Space chamber 20)
28. Channel (the inlet duct communicates with 50. Space the outlet duct 26 via a channel 28)
29. Seat (for the body of the cut-off valve 30) 51. Passagewav
30. Cut-off valve 52. Throttling member
31. Section of the stem 53. Dowel
-32. Section of the stem 54. Distal end
33. Arial bore (in the entire stem 31-32) 55. Ferrule
34. K_ob-shaped head of Section 31 56. Seat
35. Radial perforations 57. Perforation
36. Spring 58. Perforation
37. Second cut-off valve
For splicing experiment, three types of yarn were selected i.e., S3, S4 and S5. These yarns were doubled together into 6-ply, 6-ply and 10-ply respectively. The sample details are compiled in Table 5. The purpose of plying so many raw silk yarns was two-fold.
1. The procedure adopted for splicing is to soften the sericin and use the baves as filaments
for splicing. A 6-ply yarn of 33 denier (S3) is expected to have about 120 baves and similarly 6-ply and 10-ply yarns of 45 denier and 27 denier respectively arc expected to have about 192 and 220 baves. Hence the chances of an entangled joint are improved for such a plied assembly.
2. The splicers available are meant for a relatively medium to coarse count range. A yarn of
20 denier would be two thin to handle in such a splicer. Hence as and when actual splicing experiments would be attempted with the splicers, a count in the range of 200 270 denier would be easier to process.
Table 5 Sample details of preliminary experiment for splicing
(Table Removed)

Experimentation involved establishing the proposition that soften the yarn in presence of heat and moisture and then subjecting it to a blast of air to temporarily open up the glued structure of the raw silk. Hence it was decided to immerse each sample in hot water for specific period of time and then put in a hand held splicer for being subjected to a blast of air. Such yarn samples were then to be viewed under microscope for observing the effect. The combination of temperature of water and duration of immersion of yarn were selected as listed in Table 6 Table 6 Combinations for Temperature of water and duration of immersion of yarn
(Table Removed)

Some of the views of the original raw silk and those obtained after the blasts are reproduced in Fig 4, 5 and 6. The coding adopted for each image refers to the water temperature, the duration of immersion and the magnification employed in the microscope.
The images obtained after subjecting S3, S4 and S5 to die blast of air are shown in Fig 4, 5 and 6. It can be observed in all the cases that after immersion of the yarn in hot water and subjecting them to blast their shape has been changed from cylindrical to flat. Also one marked difference was observed that the original yarn is like a solid cylindrical rod but the yarn after the treatment has been dispersed into similar cylindrical rods which of course are baves. These baves are obtained due to softening of the sericin film covering the baves and thus spreading them apart when subjected to blast of air. It was observed while splicing the silk yarn, on softening of sericin if the yarn is subjected to blast of air then individual baves can be separated, thus leading -to intermingling resulting into a strong bond on cooling. On cooling the sericin bind the joint.
A close observation of the images of the sample S3 shows that the combination of temperature and time, 100"C, 1 min and 100"C, V/z min is best suited for splicing conditions,
followed by the combination 80C, 1 min. Sample S-4 shows the best results :it 70 C2 min; XO'C -11/2 min and 90C, 2 min. In the case of Sample S5, best combinations were observed at 80"C -11/2 min and 90' C, 2 min. In the case of Samples S5, best combinations were observed as 80"C, -11/2 min; 100C, 1 min and 100'C -11/2 min. Moreover, while analyzing between samples, some of the good images were observed in the case of sample S7 followed by S8.
It may however be noted that between immersion of samples in hot water and blasting the same in hand held splicer, a certain time of about 20 30s elapsed, during which the sample would be cooled down to a degree. Moreover, the temperature of sample in no case reached the temperature of hot water during the period of immersion. Thus when the individual samples were blasted, the prevailing temperature was lowered down. The cold air blast would also cool down the samples very easily. Nonetheless the temperature and duration of splicing would apparently be affected by the quality of Sericin-3. Splicing with steam
On the basis of results of preliminary experiment for splicing it was found that on immersion of silk multifilament yarn in hot warer and then subjecting it to blast of air filamentation takes place. As can be observed through the microscopic images obtained in Fig 4, 5 and 6, an individual silk filament of the multi filament has been filamented due to softening of sericin when it is immersed in hot water and after that on subjecting it to blast of air the individual baves in the filament got segregated. This gave an idea to splice silk multifilament yarn with the help of steam. Thus the splicer was connected to the boiler line with the help of steam pipe. The ends of the yarn samples were placed in the blending chamber and were subjected to a steam blast. The spliced samples were then visualized under microscope as shown in Fig. 7.
On splicing with steam alone the spliced joint did not retain enough strength. As can be viewed from the spliced images shown in Fig 7 the spliced joints exhibit low strength and are not neat in appearance. This could be due to reason that on subjecting the yarn to high temperature, the sericin is washed away at that point and thus could not be useful in fulfilling the purpose of forming the bond. However, filamentation of the yarn ends along with intermingling occurs. Splicing with a mixture of steam and air
Splicing with steam alone could not provide good results, so then it was decided to lower down the temperature of steam as it reaches the nozzle by blending it with air. The equipments used for splicing are described as follows: Valves
Two types of valves are used in the set-up for splicing as shown in Fig 8. The straight -flow valve is used for supply of steam and the angle-flow valve is used for supply of air.

The mechanical check valves that permit gases and liquids flow in only one direction, preventing process flow from reversing are classified as one wav directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the valve closed. The mechanics of check valve operation is not complicated. Most check valves contain a ball that sits freely above the seat, which has only one through hole. The ball has a slightly larger diameter than that of the through hole. When the pressure behind the scat exceeds the pressure below the seat, the ball returns to rest in the seat, forming a seal that prevents backflow.
The valves used in steam systems have flexible gates. The reason for using a flexible gate is to prevent binding of the gate within the valve when the valve is in the closed position. When steam lines are heated, they will expand, causing some distortion of valve bodies. If a solid gate fits snugly between the seat of a valve in a cold steam system, when the svstem is heated and pipes elongate, the seats will compress against the gate, wedging the gate between them and clamping the valve shut. This problem is overcome by use of a flexible gate (two circular plates "attached to each other with a flexible hub in the middle). This design allows the gate to flex as the valve seat compresses it, thereby preventing clamping.
The pipe used for supplying the mixture of steam and air to the splicer is a thick Teflon pipe with a shielding of braided steel wire. For further insulation the pipe is covered with a rubber hose so that the air steam mixture during its passage to the splicer does not lose heat.
A T-Joint device is used to connect the three devices i.e. the hand held splicer with steam supplying boiler and air supplying compressor.
A boiler is used for supplying steam to the splicer. The steam can be supplied at a pressure ranging from 0 to 21 kg/cm2.
The Compressor is used to supply air at the desired pressure. The compressor employed for the experiments can supply air in the range of 0 to 28 kg/cm".
The hand held type varn splicing device used for the experiment is Mesdan Jointair of the Type 110. It is generally used for flat and low twisted filaments yarns and long staple spurn yarns. The capacity of the splicer for filament yarns is 10-4000 denier and for staple yarns 100's - 2's NE. It is small and portable and includes a handle portion to allow the user to operate the device easily with one hand as shown in Fig 9.
It is characterized by comprising clamp members that grip a yarn to be spliced, a cutter member that cuts one side of the gripped yarn to expose end surfaces of the yarn, splicing prism and a covering member generally made of rubber, but it has been replace by Teflon so as to permit use of steam.
A hand-held pneumatic yarn splicing device has a splicing prism into which a pair of yarn ends to be spliced together may be placed, the chamber having at least one air inlet extending

into" the prism for directing air from a high pressure source external of the device into the prism. The prism is interchangeable with other prism and has a pair of projections extending from the wall of the prism to break up the twist of yarns which are to be spliced together by the action of the high pressure fluid. The prism is rectangular and has a center axial bore and the projections extend radially from the inner wall of the prism.
The splicer is held in one hand with the thumb placed lightly on the trigger. The yarns to be spliced are held in the other hand and located into the entry slot. The index finger closes off and seals the bore and holds the two yarns, while the other hand holds the yarn against the cutting blade to sever the yarn ends. The trigger is then depressed for a few seconds and after release, the yarns are spliced together.
The splicing process for raw silk yarn has been designed keeping in mind the gummy substance called sericin-1 which binds the twin brins together to form a bavc.
Sericin is a complex protein composed of three distinct components (I, II and III) of which sericin III is the interior layer directly adjacent to the fibroin core. The sericin I outer layer is the most soluble of the three constituents, while sericin HI is most difficult to dissolve. Viewed as a cross section, the brins have the appearance of equilateral triangles with rounded corners that face each other at their respective bases.
So, for the purpose of splicing multifilament a set up has been designed so that a mixture of steam and air can be passed through the splicer. In this process air has been mixed with steam to lower down its temperature, because sericin-I needs around 70-75"C temperature for softening. For air supply compressor and for steam supply boiler was used. Both supplied are connected to the splicer with the help of T-joint. To avoid the possibility- of backflow valves have been connected before the passage of both air and steam into the T-joint. Raw silk multifilament yarn was then spliced by adjusting different temperatures and pressure of the jet of mixture of air steam coming out of the splicer nozzle. The arrangement for the splicing system is -as shown in Fig 10
The sample was prepared by combining six raw silk yarn of 45 denier to a single yarn having 270 denier. The purpose of combining six filaments into one was having 32 baves in its cross-section and when six of such kind of yarns were combined it constituted to around 192 baves. Hence as the main idea for splicing is to soften the sericin and use the baves as filaments for splicing, so the plied yarn was used. The spliced yarns were subsequently transferred to the viewing board for visual appraisal. (Fig 11) The experiment was carried out by first keeping the pressure of air fixed and varying the pressure of steam. The pressure of air was fixed at 5 bar and pressure of steam as gradually increased. Splicing was performed at a pressure of 2.5 bar and 4 bar of steam. After splicing the images of the joint were viewed under microscope. It was

observed that as the pressure of steam was changed, consequently the appearance of the spliced joint also undergone change. When the pressure of steam was low i.e. around 2.5 bar the spliced joint was not quite neat in appearance. There was lot of protruding baves as can be observed in Fig. 12. But when the pressure was increased to 4 bar then the spliced joint was much neater and compact as can be observed in Fig 13.
Splicing with the help of steam and air, produced considerably better results as compared to splicing with the help of only steam. Fresh spliced joints were generated to investigate the strength and appearance of the joint. The testing procedure is illustrated as follows:
The sample used for performing experiment has the following details Yarn: Mulberry Bivoltine, 27 denier, 10-plied Air pressure: 4kg/cm2 Steam pressure: 4.8kg/cm2 Combined pressure of air and steam: 4.6kg/cm2
It was observed that appearance of the spliced joint changed with change in the pressure. When the pressure of steam was low i.e. around 2.5 bar the spliced joint was not quite neat in appearance. There were a number of protruding baves as can be observed in I-'ig. 12. When the pressure was increased to 4 bar, the spliced joint was much neater and compact as can be observed in Fig 13.
Moreover, in Fig 12 and Fig 13 it can be observed that in the process of splicing alongwith filamentation of yarn some wrapping and twisting also has taken place. This is expected to provide strength to the joint.
Yarns breaking strength is an important indicator of the performance of spliced yarns under different splicing conditions. Instron 4201, interfaced with a computer was used to test the breaking strength of parent and spliced yarns. The specimen length was set at 100mm and the rate of displacement of the testing machine at 200mm/min.
Breaking strength of the spliced joint is expressed as retained spliced strength (RSS) rather than actual breaking load.
Retained Splice strength = Splice strength x 100
Parent yarn strength Similarly Elongation of the spliced joint is expressed as retained splice elongation (RSE) rather than actual breaking elongation.
Retained Splice strength = Splice Elongation x 100
Parent yarn Elongation It was found that the maximum strength of the spliced joint was 2.665 g/d, as compared to 4.433g/d of the parent yarn. Thus RSS evaluates to approximately 60.12%.

Also the maximum elongation of the spliced joint was 5.747% as compared lo 9.970% <>f" the parent yarn. Thus RSI'' evaluates to approximately 57.64%.
The values of RSS and RSE though cannot be considered as satisfactory, indicate that this process has the potential of further improvement through optimization.
The diameter of the spliced joints was measured with the aid of Leica microscope, by acquiring the image of the spliced joints. The average of the spliced portion was calculated, along with the diameter of corresponding parent yarns.
The spliced yarn diameter is expressed as increase in diameter (%) rather than actual diameter values.
Increase in diameter (%) = [Dia of spliced ayrn] - [Dia of parent yam] x 100
Dia of parent yarn It was found that increase in diameter of spliced yarn was around 43% compared to the parent yarn. The spliced joint diameter can be reduced to some extent by optimizing the process. The temperature, pressure and the duration of the jet of air and steam mixture ejecting out from the nozzle of the splicer can be controlled bv optimization. This aids in estimating that among various combinations of temperature and pressure of steam and air, along with the duration of the blast, which would provide the best possible spliced joint. This optimization is required because correct amount of steam and air should eject out from the nozzle for a correct duration. Too high quantity of steam in the jet can lead to dissolving of the sericin instead of just softening. On the other hand, too low the quantity of steam in the jet would not be able to soften the sericin. Thus for process efficiency and product quality optimization of the process is necessary. Moreover it will be useful in reproducibility of the results in future. Pressure and temperature relationship of steam and air
A system for setting air pressure and steam pressure for achieving required temperature and pressure of the mixture entering the splicer was calibrated. Equations were developed to adjust the desired value of temperature and pressure of the mixture of steam and air .above.
For earning out this experiment, the air pressure was held constant at 4kg/cm2 and the steam pressure was slowly increased in steps from 2.5kg/cm2 to 6 kg/cm". Temperature of the mixture was noted by a laser temperature measuring device and pressure of mixture read out from the gauge. Subsequendy, the same experiment was repeated by lowering the steam pressure in steps from 6kg/cm2 to 2.5kg/cm2. The air pressure was subsequendy increased to a higher value of 5kg/cm2and whole set to experiments repeated. Results of the experiment are plotted in Fig 14 and 15after carrying out regression analysis.
A regression equation was derived from the surface lot of pressure of mixture with pressure of air and steam (Fig 14). Through this equation it would be easy to adjust the pressures

of air and steam for a given pressure of the mixture. Kquatiou for temperitnre of the mixture
and pressure of the mixture has also been derived, so that the temperature of the jet of stream
ejecting from the nozzle can be estimated (Fig 15). This study would further be beneficial in
optimization of the process. The temperature and pressure of the ejecting jet can be estimated at
which the spliced joint gives the best performance, by earning out splicing at different
temperature and pressure combinations. The regression equation is
Pmix = 0.15 + 0.561 Ps + 0.379 Pa R2 - 0.756
_ Regression Equation:
Tmix = 3.75 Pmix + 55.286 R2 - 0.976
Splicing prisms
The prism is the main part of the splicer where actual splicing takes place. The prism bodies are designed such that in the yarn pickup position there is sufficient space provided between the prism bodies for inserting the yam that is to be spliced together. For different kinds of yarns and fibers, and different counts of yarn different kinds splicing prism are used.
The structural details and parameters of the splicing chambei are show n in 1 ig 16,17 and
18 with their numerical values shown in Table 7. The air intake ports are positioned in the
channel according to the direction of twist in the Yarn. If a Z-twist yarn has to be spliced than
DZl, DZ3, DZ1/16.1E, DZ3/16.1E etc. prisms can be used. While for splicing S-twist yarn,
~DS1, DS3 etc. prisms can be used.
From Table 7, it is evident that prisms DZl, DSI and DZl/16.IE are used for coarser counts of yarn because their channel width (12) and air intake port diameter (dl) are high as compared to DZ3, DS3 and DZ3/16.1E. Channel width (12) inadvertendy the splicing prism is related to the count of yarn. Coarser the yarn or in other words thicker the yarn, higher the channel width required so that the yarn can be properly placed in the channel. Too high or too low spacing can affect the structure of spliced joint. If for instance DZ3 is used for coarser count yarn, though the splicing would Lake place but there would be protruding fibers which would not be twisted properly thereby affecting the appearance of the spliced joint. Similar will be the case if for instance DZl is used for finer count of yarn. The spliced joint would not be compact enough which would lead to loss of strength.
Air intake port (dl) are the two hole in the nozzle through which the fluid is ejected with pressure on the broken yarn ends to be joined. Coarser yarn need less velocity- of fluid to open up for facilitating intermingling, whereas for finer yarns opposite is the case. Finer yarns require velocity to open up and intermingle. This might be because the finer yarns have more twist than coarse yarns of same count so greater kinetic energy is required to open up the yarn. Moreover, finer yarns are made up of finer fibres and hence per unit area of cross-section there would be

more number of fibres inadvertently a finer yarn. Hence the air intake ports are larger for coarser yarns and smaller for finer yarns.
Air intake port spacing (db) also depends upon count of vain. for finer varus the ports spacing is higher, while for coarser it is lower. So, here DZ3, DS3 AND DZ3/16.1E are having greater air intake port spacing as compared to DZ1, DS1 AND DZ1 /16.111
Moreover, for DZ1/16.1K and DZ3/16.1E a venting channel has been provided for flow of air. The port spacing of these prism is much higher greater than their counterparts DZ 1, DS1 AND DZ3, DS3 respectively. Depending on the air pressure inadvertentlv the chamber, -these channels might permit radial flow of air for aiding inadvertently intermingling of fibres.
It was also observed that the nature of prism is independent of the splicing fluid and its temperature. The same prism can be used with different fluid and can be operated at different temperatures. Based on this study, it may be inferred that for splicing of Mulberry Silk yarns, the splicing chamber should have appropriately narrow channels and have inlet ports of small diameter spaced apart by more than 7mm. Additional venting channels would also be desirable.
The abbreviations used in Fig(s) 16, 17 and 18 and Table 7 aie listed as follows: List of dimensions:
1: Splicer prism length
b: Splicer prism length
h: Splicer prism length
12: Splicing channel width
wl: Splicing channel width
db: Air intake port spacing
dl: Air intake port diameter
61: Splicing channel angle Table 7 Splicer Prism dimensions
(Table Removed)

Silk possesses high co-efficient of friction which posses problems in mechanical processing of silk i.e. during winding, warping and fabric manufacturing (weaving and knitting).

This co-efficient of friction by means of lubrication of raw undcgmnned silk filament yarn. The lubricants used were amino silicone available in laboratory and amino functional poly siloxane, procured from Clariant. The main reason for selecting lubricants is their low surface tension and non-reactive nature. Also, they are non-toxic and can be removed during degumming.
The present invention is described with reference to the following illustrative example, and should not be construed to limit the scope of the present invention. Example
The co-efficient of friction by means of lubrication of raw undegummed silk filament
yarn. Firstly, the raw undegummed silk filament yarn of 90/95 denier was made into hank form
and then conditioned and weighed. These hanks were then treated with silicone emulsions. The
different methods of treatment of the hanks with silicone emulsion carried out to find out the
best suitable method from the view of applicability, performance and economic aspects. The
different methods are discussed in Table 8.
Table 8 Methods of lubrication of silk yarn
(Table Removed)
The raw silk filament yarns which were lubricated with silicone' emulsion as discussed above were then tested for coefficient of friction. In order to perform the test, the hanks were first converted to cone.
The coefficient of friction of the original yarn and the treated yarns was measured on Lawson-Hemphill Digital Friction Meter, DFM which is a small, laboratory size instrument.
In this instrument the ratio of input to output tension is established directly and the coefficient of friction is indicated on the scale as is evident from Fig. 19
The coefficient of friction values and the corresponding add on percentages have been listed inadvertently Table 9. The co-efficient of friction of the parent varn was measured to be 0.25. It has been observed that though co-efficient of friction has been reduced considerable after treatment with silicone emulsion, the value of coefficient of friction has not undergone significant change for different methods of silicone treatment. Generally the value is ranging from 0.18 to 0.2, except for silicone spray for which there was no change inadvertently coefficient of friction value, it has remained same as that of untreated year i.e. 0.25.
Though 1A, IB and 1C samples have shown good results, with low add-uii percentages. Considering from the industry perspective, as the method of application of lubricant is exhaust method, so it wouldn't be functionally feasible as the process would require extra time thus reducing the efficiency of the process.
Considering 2A and 2B processes, inadvertendy these cases the hank of yarn is directly immersed inadvertendy the emulsion without diluting it, so though the coefficient of friction values are 0.18, but add-on percentage is more. Thus, though this process can be less time consuming, but on the other hand it is not economically feasible, as more of the emulsion would be required without creating any difference inadvertendy the coefficient of friction values.
Considering 2C, 2D, 2E, 2F and 2G, it can be observed that they are having rriinimum range of add-on percentage, with coefficient of friction value increasing as the add-on percentage is decreasing. Basically these samples had been prepared by immersion the silk hanks inadvertendy diluted silicone emulsion of 30gpl, 20gpl, lOgpl, and 5gpl respectively. Though inadvertendy case of 2G, the add-on percentage is low but the co-efficient of friction value is slighdy higher as is the case with 2F. Inadvertendy case of 2C, 2D and 2E, though the add-on percentage is somewhat more than that of 2F and 2G, but along with that the coefficient of friction value also is towards lower side. Thus this process can be taken into consideration as economically and functionally feasible. Last process in which silicone spray was used did not reveal good results. The coefficient of friction value remained same as that of original yarn and the add-on percentage also was high

Table 9 Coefficient of friction and add-on percentage for silicone treated yarns.
(Table Removed)

We claim:
1. A method for the mechanical process of silk varn comprising subjecting a silk varn to
softening by treating with heat and moisture and then a hot air blast in order to open the
glued structure of said yarn and thereafter subjecting said softened silk to splicing using a
hand held splicer to obtain spliced silk yarn.
2. A method as claimed in claim 1 wherein the hand held splicer is provided with a trigger
and the hot air blast is provided from a compressed air source through a tube, wherein in
the nonoperative position the cut off valve is closed and a cut off member allows a free
flow from a channel to an outlet duct, thereby arresting the compressed air coming from
the tube into the inlet duct in the portion of the channel upstream of the valve.
3. A method as claimed in claim 1 wherein the varn to be spliced is placed in a blending
chamber of the splicer unit and the prcsser actuated by a trigger to bear against the head
of the stem of the valve against the bias of a spring, the valve being opened to
instantaneously provide compressed air through the channel and the outlet duct, the
splicing being carried out inside said chamber, while simultaneously ait flow is directed
through a passageway to reach a plurality of spaces provided in a timing reservoir.
4. A method as claimed in any preceding claim wherein after a working cycle is completed, the presser is released, and the cut off valve brought back to a closed position through a spring and wherein the stem section is used to clear the bores to ensure that air is discharged from the reservoir through the axial bore of the stem and through perforations on the stem.
5. A method as claimed in claim 4 wherein said perforations are oriented to clear the device from residues of fibrils which may be accumulated during operation.
6. A method as claimed in claim 4 and 5 wherein the pressure in said reservoir is decreased and the moveable wall and associated cut off member restored to starting position by discharge of air from the reservoir.
7. A hand held splicer for use in the method of any preceding claim, said splicer comprising a timing reservoir having a plurality of interconnected spaces and communicating with a fiber blending chamber, a cut-off valve provided to control air flow from an air source to the blending chamber, an auxiliary throttle to adjust the flow of compressed air from the timing reservoir to the blending chamber.
8. A splicer as claimed in claim 7 wherein the splicer is provided with a trigger, said splicer being connected to a compressed air source through a tube, wherein in the nonoperative position the cut off valve is closed and a cut off member allows a free flow from a

channel to an outlet duct, thereby arresting the compressed air coming from the rube into the inlet duct in the portion of the channel upstream of the valve.
9. A splicer as claimed in claim 7 or 8 wherein the blending chamber of said splicer is provided with a presser that in turn is operatively associated with a trigger to bear against a head of a stem of said valve against the bias of a spring.
10. A splicer as claimed in claim 7 wherein said blending chamber is provided with a moveable wall and a cut off member such that the cylindrical body thereof is insertable into a seat to cut off air flow in an outlet duct and the blending chamber.
11. A splicer as claimed in claims 7 to 10 wherein the spring is connected with said cutoff
valve and a stem section of said valve being provided with bores so that the air can be
discharged from said reservoir through an axial bore of the stem and through
perforations on said stem.
12. A splicer as claimed in claim 11 wherein said perforations are appropriately oriented so as
to clear the device from residues of fibrils which may be accumulated during operation.
_ 13. A splicer as claimed in any of claims 7 to 12 wherein the valves comprise a straight flow valve for steam supply and an angle flow valve for air supplv.
14. A splicer as claimed in any of claims 7 to 13 wherein mechanical check valves are provided to permit gases and liquids to flow in only one direction
15. A splicer as claimed in any of claims 7 to 14 wherein said pipe channel is a Teflon pipe with a shielding of braided steel wire, optionally covered with a rubber hose so that the air steam mixture during its passage to the splicer does not lose heat.
16. A splicer as claimed in any of claims 7 to 15 wherein a T-Joint device is used to connect the hand held splicer with steam supplying boiler and air supplying compressor.
17. A method of mechanical splicing of silk yarn substantially as described hereinbefore and with reference to the foregoing example and accompanying drawings.
-18. A hand held splicer used for mechanical splicing of silk yarn substantially as described hereinbefore and with reference to the foregoing example and accompanying drawings.