Abstract:
There is disclosed a method of texturing yarn products wherein the yarn product is passed along a predetermined yarn path through a liquid jet device applying a force to the yarn transversely to the axis thereof, comprising directing the liquid as it passes through the liquid jet device past an air inlet to the liquid jet device to entrain air therein.

Description:
This Application is a continuation of International Application No. PCT/GB01/04771, with an international filing date of 29 Oct. 2001, now pending, claiming priority from Great Britain Application No. GB00/26763.3, filed 2 Nov. 2000, now pending, and herein incorporated by reference. 
   TECHNICAL FIELD 
   This invention relates to the texturing of textile yarn products, in particular the jet texturing of filament and/or staple yarns, which includes the intermingling and/or the twisting of multifilament yarns, the co-mingling of two or more filament yarns and the combining of filament and staple yarns. 
   BACKGROUND OF THE INVENTION 
   It is known to perform the above processes on one or more textile yarns by passing the yarn or yarns through a jet device in which a jet or jets of air are directed transversely of the travelling yarn or yarns to agitate or twist the filaments or the fibres of the yarns. Agitation by such means may cause uniform texturing or intermittent texturing, i.e. intermingling or co-mingling. When intermittent, nips are produced in the yarn or yarns at spaced intervals. Since such jets rely on air turbulence, the degree of twist, texturing or of nip spacing along the yarn is in consequence random. Whilst the average degree of twist, texturing or nip production per unit length of yarn processed by such known jets may be satisfactory for certain textile applications, there are often long lengths of yarn produced having no twist, texture or nips. These lengths of yarn when used in knitted or woven fabrics manifest themselves as unsatisfactory regions in the fabric. To remove spin finish oil and to improve process stability it is known to wet the yarn prior to its entry into the air jet, but the above problems still exist. In addition, typically a machine for performing such processes can have many, for example 200 or more, processing positions, i.e. 200 or more yarns are processed simultaneously in parallel threadlines. The provision of high pressure air to such numbers of jets is expensive and such a machine is very noisy. 
   SUMMARY OF THE INVENTION 
   To overcome the above problems, in our co-pending International Application No PCT/GB00/02610 there is proposed a method of texturing textile yarn products comprising passing the yarn product along a predetermined yarn path through a liquid jet device applying a force to the yarn transversely to the axis thereof. It has now been found that, surprisingly, the performance of the method proposed in that application and the quality of the products produced thereby can be improved by modifying the liquid flow through the jet device. 
   The invention provides a method of texturing textile yarn products wherein the yarn product is passed along a predetermined yarn path through a liquid jet device applying a force to the yarn transversely to the axis thereof, comprising directing the liquid as it passes through the liquid jet device past an air inlet to the liquid jet device to entrain air therein. 
   The force may be applied to the yarn by the liquid prior to passing the liquid past the air inlet. Alternatively, the force may be applied to the yarn by the liquid simultaneously with passing the liquid past the air inlet. 
   The method may also comprise applying a forwarding force or a retarding force to the yarn product. The method may comprise applying at least one jet of liquid to the surface of the yarn product transversely to the axis thereof, and may comprise applying the at least one jet of liquid with components of velocity both axially of and transversely to the yarn path through the jet device. The method may comprise applying a plurality of jets of liquid disposed about the axis of the yarn path through the jet device. The method may comprise applying the plurality of jets of liquid offset from the axis of the yarn path to twist the yarn. Preferably the liquid is water and may be cold water. The supply of water may be pulsed. The method may comprise directing the air entrained along the air inlet transversely to the axis of the direction of flow of liquid through the jet device, and may comprise directing the air entrained along the air inlet with components of velocity both axially of and transversely to the flow of liquid through the jet device. 
   The yarn product may be a plurality of yarns that are combined to form a single coherent yarn. One of the yarns may be a staple yarn. Alternatively, the yarn product may be continuous filaments. 
   The invention also provides a process in which the yarn product is textured by the above method, and the process may comprise drawing the yarn product to form a partially oriented yarn. 
   The process may be controlled by a feedback arrangement. In this case a property of the yarn product may be measured and the measurement used to control the process. The measurement may be used to control the liquid jet device or a yarn product speed. The yarn product may be wound up after being textured. 
   The process may also include cooling the yarn product. The yarn may be cooled by the liquid jet device. The process may comprise heating the yarn, and may comprise twisting the yarn. The yarn product may also be cooled in a liquid immersion cooling zone, in which case a cooling liquid may be moved in contraflow to the yarn product passing through the cooling zone. The cooling zone and the liquid jet device may be contiguous. The coolant liquid may be the liquid of the jet device. 
   The invention may also comprise apparatus for texturing a yarn product comprising a liquid jet device adapted to apply to a yarn product travelling along a predetermined yarn path through the jet device a force transversely to the axis of the yarn product, the liquid jet device having a path for the liquid through the liquid jet device and an air inlet communicating with the path for the liquid. 
   The liquid jet device may be adapted to apply the force to the yarn upstream of the air inlet. Alternatively, the liquid jet device may be adapted to apply the force to the yarn simultaneously with passing the liquid past the air inlet. 
   The liquid jet device may be adapted to apply a forwarding force or a retarding force to the travelling yarn product. The jet device may apply at least one jet of liquid to the surface of the yarn product transversely to the axis thereof. The at least one jet of liquid may be directed to have velocity components both axially of and transversely to the yarn path through the jet device. A plurality of liquid jets may be disposed about the yarn path through the liquid jet device. The plurality of jets of liquid may be offset from the axis of the yarn path to twist the yarn. The liquid jet device may comprise a housing which terminates in a yarn constricting outlet, having an axis defining a yarn path therethrough, with liquid flow channels aimed towards the outlet and transverse to the axis. The housing may comprise at least one seal against liquid escape along the yarn path. The seal may be a labyrinth seal, which may be pressurised, and may be gas pressurised, e.g. by compressed air. The air inlet may extend transversely to the axis of the direction of flow of liquid through the jet device, and may extend in a direction having components both axially of and transversely to the flow of liquid through the jet device. The liquid jet device may comprise a baffle located at the outlet thereof. Preferably the liquid jet device comprises a water jet device. 
   The jet device may be arranged in the path of a plurality of yarns. Alternatively, the jet device may be arranged in a filament spinning apparatus. The apparatus may also comprise drawing means, which may be disposed upstream of the jet device. The apparatus may comprise a feedback arrangement operable to control the processing of the yarn product. The feedback arrangement may comprise a measuring instrument operable to measure a property of the yarn product, and control means operable in response to a signal from the measuring instrument proportional to the measurement to control the processing of the yarn product. The control means may be operable to control the liquid jet device and/or a yarn product speed. 
   The apparatus may comprise winding apparatus disposed downstream of the liquid jet device. The apparatus may comprise cooling apparatus. The cooling apparatus may comprise the liquid jet device. The apparatus may also comprise heating apparatus, which may be disposed upstream of the cooling apparatus. The fluid jet device may be adapted to twist the yarn. 
   The jet device may be disposed downstream of a further cooling arrangement. The further cooling arrangement may be a fluid cooling arrangement in which the yarn product passes through a fluid to be cooled by heat transfer thereto. The further cooling arrangement may comprise a cooling chamber having a fluid inlet and a fluid outlet for cooling fluid to be passed therethrough, and a yarn product inlet and yarn product outlet. The cooling fluid may be passed in contraflow relative to the yarn product. The cooling chamber may comprise seals against escape of cooling fluid at the yarn product inlet and the yarn product outlet. The seals may be labyrinth seals, which may be pressurised, and may be gas pressurised, may be by compressed air. The cooling fluid may be a liquid and may be water. The flow of liquid through the cooling chamber may be arranged to be turbulent. The jet device and the further cooling arrangement may be contiguous. The jet device and the further cooling arrangement may have a common liquid. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to the accompanying drawings in which: 
       FIG. 1  is a longitudinal section on the line  1 — 1  of  FIG. 2  of a first embodiment of liquid jet device, 
       FIG. 2  is a section on the line  2 — 2  of  FIG. 1 , 
       FIG. 3  is a section of an alternative embodiment of liquid jet device, 
       FIGS. 4 and 5  are threadline diagrams of alternative filament spinning apparatus incorporating the liquid jet device of  FIGS. 1 and 2  or  FIG. 3 , and 
       FIG. 6  is a yarn co-mingling machine incorporating the liquid jet device of  FIGS. 1 and 2  or  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIGS. 1 and 2 , there is shown a liquid jet device  10  in the form of a cylindrical body  11  having a texturing chamber  12  defining an axial path for the yarn product  13  to pass through the jet  10 . Opening into the texturing chamber  12  are inlets  14 , two being shown in this case disposed around the yarn  13 , for water or other suitable liquid provided from a source (not shown) in the direction of arrow A. The openings of the inlets  14  are transverse to the axis of the texturing chamber  12  so that the impinging jets of water are transverse to the running yarn product  13  and subject the yarn product  13  to an agitating force. The yarn product  13  is formed, in this case, by intermingling the filaments of a core yarn  15  and an effect yarn  16 . The inlets  14  are directed at an angle to the direction of running of the yarn product  13  so that the water jets have components of velocity axially of the yarn product  13  as well as transversely thereof. This applies a forwarding force to the yarn product  13  as well as the transverse force. Alternatively the inlets  14  could be inclined in the reverse direction to apply a retarding force to the yarn product  13 . The supply of water to the inlets  14  may be pulsed to produce a more even form of texturing or other desired effect. The body  11  is contained in a housing  20 . The water exits from the texturing chamber  12  through an outlet  17  in the direction of arrow B, the flow of water from the yarn inlet and outlet ends of the housing  20  being prevented by labyrinth seals  29 . The seals  29  are pressurised by gas, e.g. compressed air, fed in the direction of arrows F. Within the texturing chamber  12 , and downstream of the water inlets  14 , the water stream travelling with the yarn  13  passes an air inlet  18 . This flow of water past air inlet  18  causes air to be drawn into the jet  10  in the direction of arrow C to be entrained by the water in the chamber  12 , and thereby to increase the turbulence of the flow of the high pressure water/air mixture. On reaching the outlet  17 , the yarn  13  impinges on a baffle  19 , which provides a retardation of the yarn to increase the texturing effect. 
   Referring now to  FIG. 3 , there is shown an alternative embodiment of liquid jet device  21 . The jet device  21  has a body  22  in which there is a texturing chamber  23 . A yarn inlet bore  24  communicates with the texturing chamber  23 , and, as shown in this case, a core yarn  25  and effect yarn  26  are introduced into the jet device  21  through the inlet bore  24 . The yarns  25 ,  26  enter the texturing chamber  23  where they are combined and textured by a jet of water impinging on them from a water jet inlet  28 , thereby forming a yarn product  27 . In this case air is entrained along the yarn inlet  24  by the flow of water into the texturing chamber  23 , i.e. the force is applied to the yarn  27  by the liquid simultaneously with the liquid passing the yarn and air inlet  24 . In both embodiments of jet device  10 ,  21  described above, depending on the geometry of the water inlets  14 ,  28  relative to the axis of the texturing chamber  12 ,  23 , i.e. offset therefrom, the water jet or jets may twist the yarn. 
   Referring now to  FIG. 4 , there is shown a filament spinning apparatus  30  having a spinning head  31  from which filaments  32  are extruded. The filaments  32  are withdrawn from the spinning head  31  by a first feed roller  33 . Spin finish oil is applied to the filaments  32  by an oil applicator  36 , at which the filaments  32  are brought together to form yarns  34 , and the regularity of the oil application is improved by oil dispersion jets  37 . The yarns  34  are drawn between the spinning head  31  and the first feed roller  33 , and the resulting partially oriented yarn  38  is forwarded to a second feed roller  39 . A liquid intermingling jet  46 , which directs a jet of liquid at the yarn  38  to intermingle the filaments of the yarn  38 , is disposed in the controlled tension zone between the first and second feed rollers  33 ,  39 , but may be placed before the roller  33 . The interlaced yarn  40  is passed through an optical interlace sensor  47  to a forwarding point  41 . The interlaced partially drawn yarn  40  is then fed from the forwarding point  41  to a take up zone  42  to be wound using a traverse guide  43  onto a package  44  driven by surface contact with a driving bowl  45 . The traverse guide  43  reciprocates as shown along a path parallel with the axis of the package  44 . The interlace sensor  47  comprises an optical transmitter  48  and an optical receiver  49 , a beam from the transmitter  48  being directed at the yarn  40  and then being received by the receiver  49 . The receiver  49  sends to a control device  50  a signal, which varies in response to the changes in dimension of the intermingled yarn  40 , i.e. as interlace nodes pass the sensor  48 . The control device  50  is operable to control the supply and/or pressure of liquid to the intermingling jet  46  and/or the speed of the feed rollers  33 ,  39 , and that supply may be pulsed if desired. 
   In the case of this invention, the intermingling jet  46  is constructed and operates as the device  10  of  FIGS. 1 and 2  or  21  of  FIG. 3 , with water being introduced into the intermingling jet  46  in the direction of arrow A as described above and air being entrained into the texturing chamber of the jet  46  as described above. Conventionally, the distance between the spinning head  31  and the first feed roller  33 , the cooling chimney, is a relatively long so that the yarns  34  have cooled to a temperature at which they can be subjected to the intermingling step in the jet  46 . However, since the water and air entering the jet  46  are cold, thereby cooling the drawn yarn  38 , this may provide sufficient cooling for a significant reduction in the height of the cooling chimney whilst allowing the satisfactory intermingling of the filaments of the yarn  38  by the jet  46 . Alternatively, a further cooling device  51  may be placed in the threadline between the feed roller  33  and the intermingling jet  46 . The cooling device  51  is a cylinder through which the yarn  38  passes and into which cooling water is introduced in the direction of arrow D and from which the water exits in the direction of arrow E. With this arrangement, the cooling water passes along the cooling device  51  in turbulent contraflow to the running yarn  38 , both of which factors enhance the heat transfer from the yarn  38  to the cooling water. At the opposed ends of the cooling device  51 , the yarn inlet and yarn outlet are provided with labyrinth seals  52  which can be pressurised against escape of water therethrough. The intermingling jet  46  and the cooling device  51  are shown as contiguous, and the cooling water may pass directly from one to the other. As a further alternative, as shown in machine  53  in  FIG. 5 , and provided that the tension in the yarns  34  is not too great, the cooling device  51  and intermingling jet  46  may be disposed between the oil dispersion jets  37  and the first feed roller  33  to further reduce the height of the cooling chimney. Only one of the yarns  34  is shown passing through the respective cooling device  51  and intermingling jet  46 , for clarity. 
   A machine  60  for co-mingling two or more yarns is shown in  FIG. 6 , in this case two textile yarns  61 ,  62 . The yarns  61 ,  62 , which may be the same as, but are more usually different from, each other, for example one may be a staple yarn, are supplied on respective supply packages  63 ,  64  mounted in a creel  65 . The yarns  61 ,  62  are withdrawn from the packages  63 ,  64  by first feed roller pairs  66 ,  67  and fed along parallel tracks to respective heated rollers or draw pins  68 ,  69  to respective draw rollers  70 ,  71  and to a cooling device  72 . From the cooling device  72  the yarns  61 ,  62  pass through a co-mingling device  73  to a second feed roller pair  74 . The co-mingling device  73  is constructed and operates as jet device  10  of  FIGS. 1 and 2  or jet device  21  of  FIG. 3 . The peripheral speed of the draw rollers  70 ,  71  is greater than that of the first feed rollers  66 ,  67  so that the yarns  61 ,  62  are drawn at the draw rollers or pins  68 ,  69 , and the peripheral speed of the second feed rollers  74  is controlled relative to that of the draw rollers  70 ,  71  so that the tension in the yarns  61 ,  62  is controlled for satisfactory co-mingling of the yarns  61 ,  62 . The yarns  61 ,  62  may be drawn to differing amounts, or one of the yarns may be forwarded directly from the feed rollers  66 ,  67  to the co-mingling device  73  so as not to be heated, drawn and cooled, as required in any particular application. Also either or both of the yarns  61 ,  62  may be false twisted, for example one S-twist and one Z-twist, between the feed rollers  66 ,  67  and the co-mingling device  73 . The co-mingling device  73  agitates the yarns  61 ,  62  to co-mingle their filaments together to form a single coherent yarn  75 . The heated rollers  68 ,  69  heat the yarns  61 ,  62  to facilitate the drawing step and any false twisting step. The thus co-mingled yarn  75  is forwarded to a take up arrangement  76  in which it is wound onto a bobbin  77  driven by surface contact with a driving bowl  78 . 
   In this machine arrangement, the cooling device  72  and the co-mingling device  73  are shown to be contiguous. In addition, the water introduced into the co-mingling device  73  is forwarded therefrom to the cooling device  72  in the direction of arrow D, so that both devices  73 ,  72  use the same water. Also in the case of machine  60 , there is shown a measuring instrument  79 , which measures a property of the co-mingled yarn  75 . Such parameter may be node frequency or coherence. The measuring instrument  79  sends a signal proportional to the value of the measured parameter to a controller  80  which compares that value with a predetermined desired value. If there is a discrepancy between the two values the controller  80  is operable to control the rate or pressure of water flow to the co-mingling device  73  and/or the speed of the first feed rollers  66 ,  67 , the draw rollers  70 ,  71 , and the second feed rollers  74 . 
   By means of the invention improved texturing and intermingling are achieved by comparison with processing with air jet devices. In particular, in the case of intermingling core and effect yarns together, the core yarn provides most of the strength of the resultant textured yarn. In the present process, the core yarn is not opened or deviated as much as with the known processes, possibly due to the surface tension of the water. Although the core yarn is opened sufficiently for the effect yarn to be threaded through the core yarn and so be intermingled efficiently, it is not opened to the extent that the strength of the core yarn is seriously reduced. It has been found that air texturing produces strengths of 30–36 cN/tex, whereas strengths of 41.5 cN/tex can be produced with water/air texturing as described herein. In addition lower core overfeeds can be used in the present process, e.g. 2.9% instead of 5% to 8% with air jet texturing, to further improve the situation. These advantages are particularly important in the sewing thread market. For sewing threads, tight loops are required so as to minimise snagging and reduce needle temperatures during sewing. To achieve tighter such loops the textured yarn  75  may be heat set by passing the textured yarn  75  around a heated roll  81  as shown in  FIG. 6 . In the case of the present invention, such heat setting may enhance this property of the yarn  75  compared with that produced with air textured yarn, possibly as a result of “steaming” of the yarn during this heat setting step due to its higher water content.