US2982082A - Production of voluminous yarn - Google Patents

Description

May 2, 1961 w. POOL PRODUCTION OF VOLUMINOUS YARN Filed Oct. 14, 1955 WILL/AM POOL rron/5Y5 Patented May 2, 1 ,961

, PRODUCTION or VOLUMINOUS YARN William Pool, 'Spondon, near Derby, England, assignor to British Celanese Limited, a corporation of Great Britain Ths invention relates to the production of voluminous yarn and more particularly toa method and apparatus in which continuous filament yarn is subjected to the action of a turbulent stream of fluid to produce a yarn which has the appearance and handle of a staple yarn.

United States application Ser. No. 356,349, filed May' 21, 1953, describes a process in which yarn comprising a plural ty of continuous filaments is formed into a voluminous yarn, having loops of individual filaments projecting from the main body of the yarn, by passing the yarn through a jet through which fluid is supplied under pressure. The yarn enters the jet by way of an inlet tube, passes into a relatively wide chamber where it is subjected to a turbulent' flu'd stream and is withdrawn through a narrow orifice. As the yarn leaves the jet it may be caused to impinge against the flat smooth surface of a baflle plate arranged at an angle, e.g. 45, to the path of the yarn. The turbulence in the chamber causes the yarn to become more voluminous, loops and sinuosities of the individual filaments projecting from the main body of the yarn, and the impact of the yarn on the baffle plate increases the number of loops and makes them more uniform in size. Preferably the narrow orifice is offset slightly from the axis of the jet, its eccentricity having the effect of increasing the degree of turbulence. The major portion of the fluid leaves through the narrow orifice, along with the yarn, but it is found desrable that a minor portion should also leave through the yarn inlet.

According to the present invention a jet for the production of loopy or voluminous yarn from continuous filament yarn comprises an inlet tube extending through a chamber and provided with a jet tip, the jet tip facing and entering the mouth of a venturi passage, i.e. a passage converging steadily to a throat and then slowly enlarging, the outer surface of the jet and the mouth of the venturi co-operating to form an annular passage for a fluid stream blown under pressure into the chamber and out through the venturi. The yarn is drawn out of the jet by means of rollers and fed into the jet by similar rollers but with suflicient overfeed to allow the individual filaments of the yarn. to be formed in loops and curls by the turbulence of the air stream beyond the annular passage.

It is desirable that the first part of the venturi should not converge too rapidly, or the mouth will be too far from the outer surface of the jet tip to co-operate therewith to form an annular passage for the fluid. The vertical angle of the cone forming the mouth of the venturi should be less than 60, and preferably of the order of 40 or less. By a suitable configuration of the outer surface of the jet tip, e.g. in the form of a double cone, tapering more quickly at the tip than at the base, the

cross-section of the area of the annular passage can be made to decrease to a minimum and then suddenly to enlarge at the end of the jet. Apparently, as the velocity lence the individual filaments are formed into circular loops and curls.

The reduced pressure at the jet tip enables the jet to be operated so as to be self-threading, the compressed air stream drawing a secondary stream of air, together with the thread, through the tube and out from the venturi. An air supply pressure suitable for creating sufiicient suction to draw the thread through the inlet may also be suflicient to create the turbulence necessary to give the yarn the desired degree of loopiness. If not, however, the higher pressure required to give the necessary turbulence and loop formation can be applied after threading in has been efiected at a lower pressure. Alternatively the degree of suction in the inlet tube can be adjusted by shifting the jet tip in or out of the venturi. Two stops can then be provided on the inlet tube so that the jet can be quickly displaced from threading position to working posit'on.

The jet according to the invention can be used, if desired, in conjunction with the preferred features of the apparatus described in United States application Ser. No. 356,349. Thus a narrow outlet whose axis is offset from the axis of the jet can be provided by fitting a cap with an offset hole to'the venturi outlet. To overcome any difiiculty in threading, the cap can be made detachable so that it can be threaded manually after the jet has been threaded as described above, and then slipped over the end of the jet. Likewise, the baflie plate described in the prior specification can be employed, especially in conjunct'on with the offset outlet hole. It appears that the effect of the baflie plate is to deflect and disperse the high velocity jet'of air issuingfrom the device, thus preventing it from unduly tensioning the'yarn and pulling the loops out. In the present invention, however, the widened mouth of the venturi, unimpeded by a cap, allows the veloc'ty of the emerging air stream to diminish and so reduces the tendency to tension the yarn. This makes it possible to work without the baflle plate if desired.

The feed and take up arrangement for the yarn may comprise two sets of driving rollers, namely feed rollers and draw-oft rollers, of diiferent speeds or diameters providing the required amount of overfeed, which ma vary widely according to the type of finished yarn required. Overfeeds of the order ofl0-20%, e.g. 12 /z% are suitable for most purposes. Alternatively, a single roller may be used with two portions of difierent diameter, the yarn passing from the portion of larger diameter to the jet inlet and back from the jet outlet to the portion of smaller diameter. From the draw-ofi rollers the yarn can be led to a twisting spindle where it is twisted so as to set the loops. Since excessive tension on the yarn would pull out the loops, the degree of twisting and the spindle speed for a given count of yarn and ring diameter should be selected so that the tension remains below a certain maximum. For example, when treating 150 denier 60 filament yarn on a 4% in. diameter ring, a suitable speed and degree of twist are 4300 rpm. at 5 turns per inch. In an alternative arrangement the yarn may be passed through the jet in an already twisted state. Thus it may be withdrawn from a yarn package mounted on a revolving spindle so that the yarn is twisted as it leaves the package, or it may be withdrawn from a stationary package of pretwisted yarn. After passing through the jet the yarn is ofthe fluid (preferably air) blown through the passage 70 then taken P 011 a Winding Spindle-V increases, the pressure falls, pressure energy being con verted into kinetic energy. At the sudden enlargement,

The apparatus is suitable for treating artificial continuous filament yarns in general and particularly fibres of cellulose derivatives such as cellulose acetate and cellulose propionate, fibres of regenerated cellulose, such as viscose, and fibres of synthetic polymers such as polyhexamethylene adipamide, polyaminocaproic acid, poly acrylonitrile and polyaminotriazoles;

By way of example an apparatus for the production of voluminous yarn in accordance with the present invention will be described in more detail with reference to the accompanying drawings, in which:'

Fig. 1 is a sectional view of the jet unit,

Fig. 2 is an enlarged sectional view of the jet tip,

Fig. 3 is a diagram showing one application of the jet unit,

Fig. 4 is a diagram showing another application of the jet unit, and

Fig. 5 is an enlarged view of an end attachment for the jet unit.

The apparatus shown in Figs. 1 to 4 comprises'a jet unit 7, comprising an inlet tube 8, provided with a jet tip 9, a tubular brass body embraced by a union 11 for connecting to an air line, and an extractor end piece 12. The inlet tube 8 has an internal diameter which is greater than the diameter of the yarn to be treated and is uniform throughout the length of the tube except that the entrance 13 is enlarged to allow the yarn to enter more easily. The external surface of the tube 8 is threaded at 14 and 15 and has an intermediate smooth surface 16. On the upper threads 14 is screwed a broad head 17 having a knurled outer surface 18 and a fiange19 and secured to the inlet tube 8 by means of a set screw 20. On the lower threads 15 is screwed a collar 21 and the jet tip 9. The brass body ltl has an internal passage in the upper part of which the smooth part 16 of inlet tube 8 is adapted to slide. The lower part has a larger diameter and forms a chamber .22 around the inlet tube 8. The brass body 10 is formed with a flange 23, a circumferential groove 24 and a thread 25. Four radial holes 26 are drilled'in the groove 24 at equal spacing. The union 11 has an axial passage 27 communicatingwith the groove 24, and a thread 28 for connecting to a compressed air line. The union 11 is adapted to fit over the body 10 and is held against the flange 23 by a nut 31 and washer 32. Compressed air then flows from the air line (not shown) through the passage 27, groove 24, and holes 26, and into the chamber 22.

A coil spring 33 is compressed between the body 16 and the head 17 under the flange 23. The inlet tube 8 is prevented from leaving the body 10 under the pressure of the spring 33 by the collar 21, abutting against the inside wall of the body 10. The inlet tube 8 can be moved axially within the body 10 by depressing the head 17 until the edge of the flange 19 engages the surface of the body 10. On the thread 25 of the body 10 is screwed the extractor end-piece 12. This consists of a block with a passage in axial alignment with the inlet tube 8. The passage is of venturi form, having a wide conical entrance 35 leading to a narrow throat 36 and opening out gradually again to the outlet 37. The jet tip 9 is screwed on the end of the inlet tube 8 and enters the conical entrance 35 of the venturi. Its outer surface consists of two cones, the first one 38 nearer the tip having a vertical angle larger than that of the inlet cone 39 of the venturi and the other 41 having an angle smaller than the cone 39 of the venturi. tip is therefore annular. Its cross-section first decreases to a throat 42 after which it remains approximately constant until the end of the jet tip 9 is reached, Where the air passage ceases to be annular and increases suddenly in cross-section. The extractor end 12 can be removed for cleaning or for clearing the jet tip 9 without risk of disturbing the jet setting.

To thread the jet unit 7, the end of a continuous filament yarn 43 is presented to the enlarged entrance 13 of the inlet tube 8. Compressed air is supplied to the The space between the venturi and the jet 6 chamber 2 2 and the head 17 of the inlet tube 8 is depressed so that the suction effect draws the yarn 43 through the inlet tube 8. When the yarn emerges from the venturi, the inlet tube 8 is allowed to return to its normal position under the force of spring 33. The position of the jet tip 9 relative to the extractor 12 is then such that the air flow creates a vortex which, in combination with the strong extractor effect of the venturi causes the filaments in the yarn to be folded into circular loops or curls without breakage of the filaments.

The jet unit can be used in conjunction with a downtwister spindle as shown in Fig. 3. The apparatus comprises a feed and take-up roller unit comprising a single roller having two portions of different diameters. The yarn 43 is drawn from a supply package (not shown) and passes first round the portion of large diameter 44, and then upwards through the jet unit 7. It is then drawn back to the nip between the small-diameter roller 'portion 45 and a cork roller 46, and through a pig-tail guide 48,

and is finally twisted and taken up on the ring spindle 49. A loaded roller 47 of suitable diameter is provided to hold the yarn in contact with the roller portion 44. The

difference in diameter of the two portions 44 and 45 allowsfor the required amount of contraction of the looped yarn. Twist is inserted in the yarn by the time it leaves the pig-tail guide 48, so that the loops are locked in position before they can be pulled out by the thread tension imparted by the thread balloon of the ring spindle.

The jet unit 7 can also be used to manufacture voluminous yarn from yarn which is already twisted as shown in Fig. 4. The yarn 51 is drawn upwardly from the stationary supply package 52 of pre-twisted yarn, forwarded by feed rollers 53, passed upwards through the jet unit 7, and through a tension device 54, and is taken-up on the drum driven winding spindle 55. The rate of feed imposed by the rollers 53 is higher than the rate of takeup so as to allow for the contraction in the looped yarn. In an alternative arrangement the supply package 52 is rotated, so that the yarn 51 is twisted as it is withdrawn.

To increase the number of loops and curls in the yarn the extractor end piece 12 may also be provided with a removable cap 56 as shown in Fig. 5. The cap is a push fit on the extractor 12 and is held in position by means of bayonet fitting pins 57 engaging corresponding slots 58 in the cap. The cap is formed with a hole 59 which, when the cap is in position, is off-set relatively to the axis of the venturi. The yarn is threaded through the jet unit 7 before the cap 56 is placed on as described above. The yarn is then threaded through the hole 59 by hand and the cap 56 is placed on the extractor end piece 12.

Having described my invention what I desire to secure by Letters Patent is:

1. An apparatus for the production of loopy or volumlnous yarn from a continuous filament yarn, said apparatus comprising feed means for forwarding continuous filament yarn at a determined speed, a voluminising jet having an inlet tube extending through a chamber and provided with a jet tip whose outer surface is in the form of two truncated cones, the one nearer the outlet of said tube having a larger vertical angle than the other. said tip facing and partially entering the mouth of a ventun passage leading out of said chamber directly into the atmosphere, said mouth being in the shape of a cone having a vertical angle intermediate between the angles of said jet tip and less than 60 and co-operating with the outer surface of said tip to form an annular passage having an annular throat, means for supplying a gaseous fluid under pressure to said chamber whereby said fluid is blown out through said annular passage into a zone of substantially atmospheric pressure, and yarn draw-oil V means adapted to withdraw yarn through said venturi 2. An apparatus for the production of loopy or voluminous yarn from a continuous filament yarn, said appa ratus comprising feed means for forwarding continuous filament yarn at a determined speed, a voluminising jet having an inlet tube extending through and axially movable in a chamber and provided with a jet tip having a Working position facing and entering the mouth of a venturi passageleading out of said chamber directly into the atmosphere, said mouth being in the shape of a cone having a verticle angle of less than 60- and co-operating with the outer surface of said tip to form an annular passage, stop means for locating said jet tip in two ex treme positions for working and for threading-up respectively, resilient means for urging said jet tip towards said working position, means for supplying a gaseous fluid under pressure to said chamber whereby said fluid is blown out through said annular passage into a zone of substantially atmospheric pressure, and yarn draw-01f means adapted to withdraw yarn through said ventun' passage at a determined speed lower than that of said feed means.

3. An apparatus for the production of loopy or volu- V minous yarn from a continuous filament yarn, said appa- 6 facing and entering the mouth of a venturi passage leading out of said chamber directly into the atmosphere, said mouth being in the shape of a cone having a vertical an gle intermediate between the angles of said jet tip and less' than and co-operating with the outer surface of said tip to form an annular passage, stop means for locating said jet tip in two extreme positions for working References Cited in the file of this patent UNITED STATES PATENTS 2,526,775 Slayter et a1. Oct. 24, 1950 2,622,961 Finlayson et a1. Dec. 23, 1952 2,638,146 Rounseville et a1. May 12, 1953 2,667,964 Miller Feb. 2, 1954 2,733,869 Bunch Feb. 7, 1956 2,783,609 Breen Mar. 5, 1957 2,807,862 Griset Oct. 1, 1957 2,852,906 Breen Sept. 23, 1958 2,884,756 Head May 5, 1959 FOREIGN PATENTS 161,076 Australia Feb. 10,1955

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