Patent Application
20120192541
The present invention relates to a component for an air jet spinning arrangement, in particular a spindle point, comprising a yarn withdrawal channel comprising an entry opening for withdrawing a yarn from a vortex chamber of an air jet spinning arrangement.
A component of this type is prior art in German published patent application DE 103 33 411 A1. The component, in which the entry opening for withdrawing a yarn out of the vortex chamber of the air jet spinning arrangement is comprised, is denoted as a spindle point in German published patent application DE 103 33 411 A1. The spindle point is arranged on a stationary spindle-like component which comprises an extension of a yarn withdrawal channel. The spindle point comprises an injector channel for feeding back a yarn during a piecing process. In order to start up the air jet spinning arrangement after an end-break, a yarn end of a spun yarn is fed back counter to the withdrawal direction of the yarn through the air jet spinning arrangement and placed in the area of a drafting unit. The injector channel is connected to a compressed air source while the yarn end is being fed back. The air from the injector channel flows into the yarn withdrawal channel and generates there an air current counter to the withdrawal direction of the yarn.
In the known embodiment, air vortices may occur in the yarn withdrawal channel which hinder the correct feed back of the yarn end.
It is an object of the present invention to create an improved component for an air jet spinning arrangement in order to improve the feed back of a yarn end during the piecing process.
This object has been achieved in that the component comprises at least one air outlet opening connected to the yarn withdrawal channel for discharging air from the yarn withdrawal channel during a piecing process.
The component according to the present invention can be formed by means of a spindle-like component which is insertable into the air jet spinning arrangement. In an advantageous embodiment the spindle-like component is designed as a multipart component and comprises a component denoted as a “spindle point”. In this case the spindle point is the component of the present invention.
By means of the air outlet opening, a part of the air which flows through the injector channel into the yarn withdrawal channel can be selectively discharged out of the yarn withdrawal channel. The air outlet opening leads advantageously into the vortex chamber or into an air discharging channel surrounding the spindle point. An air outlet opening has the advantage that not all the air coming from the yarn withdrawal channel has to be expelled through the entry opening of the yarn withdrawal channel. The air vortices in the yarn withdrawal channel can hereby be reduced so that the feeding back of a yarn end during piecing is carried out significantly more reliably. Disorientation or catching of the yarn end in the yarn withdrawal channel is avoided.
The component advantageously comprises an injector channel for feeding back a yarn end counter to the withdrawal direction during a piecing process, whereby the injector channel connectable to the compressed air source is connected by means of an opening to the yarn withdrawal channel and is directed towards the entry opening of the yarn withdrawal channel. It is advantageous that an air outlet opening is connected to the yarn withdrawal channel between the entry opening of the yarn withdrawal channel and the opening of the injector channel. By means of this arrangement, the air blown through the injector channel into the yarn withdrawal channel can partly escape again out of the yarn withdrawal channel through the air outlet opening. Only a small percentage of the air flows, counter to the yarn withdrawal direction, out of the entry opening of the yarn withdrawal channel. An arrangement in this way is in particular advantageous when the entry opening of the yarn withdrawal channel comprises a free cross section area which is smaller than the free cross section area of the yarn withdrawal channel in the area of the opening of the injector channel. The yarn withdrawal channel advantageously comprises—as seen in withdrawal direction of the yarn during the spinning process—a cross sectional enlargement. This cross sectional enlagement is advantageously arranged at a short distance—as seen in withdrawal direction of the yarn downstream—from the entry opening of the yarn withdrawal channel. The distance measures advantageously between 2 and 3 millimeters. The cross sectional enlargement is very advantageously arranged between the entry opening of the yarn withdrawal channel and the opening of the injector channel. The distance between the entry opening of the yarn withdrawal channel and the opening of the injector channel measures advantageously less than 20 mm, and may advantageously lie in the area of between 3 and 5 mm.
It is advantageous that an air outlet opening is connected to the yarn withdrawal channel between the cross sectional enlargement and the opening of the injection channel.
In an embodiment of the present invention, it can be provided that the yarn withdrawal channel—as seen in withdrawal direction of the yarn—comprises a number of cross sectional extensions arranged one behind the other. At least one air outlet opening is then advantageously arranged between two cross sectional extensions. A successive mounting of a number of cross-sectional enlargments and air outlet openings effect a particularly good suppression of vortices in the yarn withdrawal channel so that the process of feeding back of a yarn end is greatly improved.
In a further embodiment of the present invention it is provided that an air outlet opening extends essentially perpendicular to the yarn withdrawal channel. An air outlet opening extending perpendicular to the yarn withdrawal channel is very simple to manufacture. To improve air expulsion, it can be advantageous to arrange a number of air outlet openings uniformly on the periphery of the yarn withdrawal channel. It is advantageous that the free cross section area of the air outlet openings corresponds at least to the free cross section area of the entry opening of the yarn withdrawal channel. It is advantageous for a reliable discharge of the air blown in by the injector channel when the free cross section area of the air outlet openings of the yarn withdrawal channel approximates twice to ten times the free cross section area of the entry opening of the yarn withdrawal channel. In the case of very small entry openings, for example in the case of an entry opening diameter of 0.8 mm or smaller, a particular good air discharge is achieved when the free cross section area of the air outlet openings approximate four times the free cross section area of the entry opening of the yarn withdrawal channel.
These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawings wherein:
The air jet spinning arrangement shown in
The staple fibre strand 3 to be spun is fed to the drafting unit 4 in drafting direction and withdrawn as a spun yarn 2 in yarn withdrawal direction B and fed further to a winding device (not shown). The only partly shown drafting unit 4 is preferably a four-cylinder drafting device and comprises therefore four roller pairs, each of which comprises a driven bottom roller and an upper roller designed as a pressure roller. Only the delivery roller pair 5, 6 is shown, which borders the drafting zone of the drafting device 4. In a drafting unit 4 of this type the staple fibre strand 3 is drafted to the desired degree of fineness. Directly downstream of the nipping line of the delivery roller pair 5,6 of the drafting unit 4 a thin fibre strand 7 is present, which is completely drafted and still twist-free.
The fibre strand 7 is fed via a fibre feed channel 8 to the air jet spinning arrangement 1. Downstream thereof lies a so-called vortex chamber 9, in which the fibre strand 7 receives its spinning twist, so that the spun yarn 2 is formed, which is withdrawn through a yarn withdrawal channel 10 in withdrawal direction B.
A fluid device generates a rotating vortex current during the spinning process in the vortex chamber 9 by means of blowing in compressed air through compressed air nozzles 11, which run tangentially into the vortex chamber 9. The compressed air is fed in the air jet spinning arrangement 1 during operation via a compressed air channel 12. From the compressed air channel 12 the compressed air first reaches a ring channel 13 surrounding the vortex chamber 9, to which ring channel 13 the above mentioned compressed air nozzles 11 are directly connected. The compressed air exiting out of the compressed air nozzles 11 is discharged through an air outlet opening 14. The air outlet opening 14 is arranged in a ring shape around the spindle-like component 15. The spindle-like component 15 comprises the yarn withdrawal channel 10. The spindle-like component 15 is stationary during operation.
In the area of the vortex chamber 9, an edge of a fibre guiding surface 16, acting as a twist stop, is arranged, said fibre guiding surface 16 being slightly eccentrically arranged to the yarn withdrawal channel 10 in the area of its entry opening 17. The entry opening 17 of the yarn withdrawal channel 10 is at a conically tapering end of the spindle-like component 15. The conically tapering end is designated a spinning point or spindle point 18.
In the air jet spinning arrangement 1, the fibres to be spun are, on the one hand, held together in the fibre strand 7, and thus fed from the fibre feed channel 8 into the yarn withdrawal channel 10 essentially without a spinning twist. On the other hand the fibres in the area between the fibre feed channel 8 and the yarn withdrawal channel 10 are exposed to the vortex current in the vortex chamber 9. The vortex current causes the fibres, or at least their end areas to be driven away radially from the entry opening 17 of the yarn withdrawal channel 10 and wound around the fibres already entering the yarn withdrawal channel. The yarns 2 produced by the above described air jet spinning arrangement 1 display a core comprising fibres or fibre areas extending essentially in yarn longitudinal direction without any significant twist, and an outer area in which the fibres or fibre areas are wrapped around the core. An air jet spinning arrangement 1 of this type permits very high spinning speeds, which lie in the range between 300 and 600 m per minute.
If for any reason the sliver 7 or the yarn 2 breaks, the drafting unit 4 is first stopped and the feed of the staple fibre strand 3 is interrupted. The winding device (not shown) also switches off. Before the spinning process begins again, it may be necessary to clear any bits of fibre caught in the vortex chamber 9. The spindle-like component 15 is moved along the yarn withdrawal channel 10 in yarn withdrawal direction B so that the spindle point 18 moves out of the vortex chamber 9. Fibre deposits blocking the vortex chamber 9 can then be suctioned off via the air outlet channel 14, which is connected to a vacuum source (not shown). A base body 19 of the air jet spinning arrangement 1 comprises a cylindrical receptacle 20, in which the spindle-like component 15 is inserted in a movable way by means of a cylindrical sliding surface 21. Two magnets 22 are assigned to the base body 20. The spindle-like component 15 comprises a supporting surface 23 made of a magnetic material which acts together with the said magnets 22. The magnets 22 hold the spindle-like component in its operational position. The spindle-like component 15 can be moved away from the magnetic force in yarn withdrawal direction B along the cylindrical sliding surface 21 for the purposes of clearing the vortex chamber 9. The movement of the spindle-like component 15 can be carried out manually by service personnel or automatically by means of a maintenance device travelling along the air jet spinning machine. An activating element 24, graphically only implied in the drawing, can be provided for moving the spindle-like component 15. An injector channel 29 is provided in the spindle-like component 15, said injector channel 29 leading into the yarn withdrawal channel 10. Furthermore a compressed air conduit 30 is available at the spindle-like component 15, which compressed air conduit 30 can be supplied at intervals with compressed air for supplying the injector channel 29. The injector channel is required during a piecing process. The injector channel 29 is connected at its outlet opening to the yarn withdrawal channel 10. The injector channel 29 is directed opposite to the entry opening 17 of the yarn withdrawal channel 10, so that the compressed air flowing in from the injection channel 29 generates an air stream flowing counter to the yarn withdrawal direction B. By means thereof, the end of a spun yarn 2 can be fed back through the air jet spinning arrangement 1 in the opposite direction to withdrawal direction B right up to the area of the drafting unit 4 and there incorporated into the staple fibre strand 3. The shown spindle-like component 15 consists advantageously of at least two components. A first component of the spindle-shaped 15 comprises a cylindrical sliding surface 21, a part of the yarn withdrawal channel 10 and the compressed air conduit 30. The spindle point 18 is designed as a separate component and forms a second component of the spindle-like component 15. A steel ring 33, comprising the magnetic supporting surfaces 23, provides the third component of the spindle-like component 15.
The spindle point 18 comprises a part of the yarn withdrawal channel 10, its entry opening 17 and a part of the injector channel 29 and its outlet opening 28. The spindle point 18 is inserted into the spindle-like component 15 by means of a cylindrical receptacle surface 34 and affixed by means of a set screw 35. In order to seal the transition of the injection channel 29 in the area of the spindle point 18, sealing rings 36 can be assigned to the receptacle surfaces 34. The spindle point 18 comprises a double cone on its outer contour, said double cone comprising in the area of the entry opening 17 of the withdrawal channel 10 a small conus angle, and adjoining it a large conus angle. In the area of the exit opening of the yarn withdrawal channel 10, a wear-resistant insert 37 can be applied in the spindle-like component 15.
Air outlet openings 25 are provided to improve the expulsion of air out of the yarn withdrawal channel 10 during a piecing operation. The air outlet openings 25 are connected to the yarn withdrawal channel 10 between the entry opening 17 of the yarn withdrawal channel 10 and the outlet opening 28 of the injector channel 29. The air outlet openings 25 open into the vortex chamber 9 or into the air outlet channel 14. The air outlet openings 25 are advantageously designed as bore holes in the area of the small cone angle of the spindle point 18. The air outlet openings 25 extend perpendicular to the yarn withdrawal channel 10. Several air outlet openings 25 are uniformly arranged on the periphery of the yarn withdrawal channel 10. During a piecing process, the compressed air fed into the injector channel 29 for feeding back a yarn end can be expelled in part out of the yarn withdrawal channel 10 through the air outlet openings 25. This is particularly advantageous when the yarn withdrawal channel 10—as seen in withdrawal direction B of the yarn 2—comprises a cross section enlargement 26. The cross section enlargement is arranged between the entry opening 17 of the yarn withdrawal channel 10 and the opening 28 of the injector channel 29. The air outlet openings 25 are arranged between the cross section enlargement 26 and the opening 28.
The air outlet openings 25 effect an expulsion of a percentage of the volume of air, fed in by the injection channel 29, out of the yarn withdrawal channel 10 before the air reaches the cross section enlargement 26. The remaining volume of air, which flows through the cross section enlargement 26 and through the entry opening 17, contains very little air vortices, so that the yarn end can be reliably fed back through the entry opening 17. It is particularly advantageous when the yarn end can be fed back through the yarn withdrawal channel 10 counter to the withdrawal direction B at a specified speed. A specified speed of the yarn end should most advantageously be attained by the time the yarn end reaches the area of the opening 28 and the cross section enlargement 26. It can be advantageous to lower the feed back speed of the yarn end when reaching this area. The feed back of the yarn end through the area of the cross section enlargement 26 takes place advantageously at a constant speed. A specified speed for feeding back the yarn end can increase the reliability of the entire feed back process. The risk of the yarn end catching on the cross section enlargement 26 is avoided.
In an advantageous embodiment of the present invention it can be provided that the yarn withdrawal channel 10—as seen in withdrawal direction B of the yarn—comprises a number of cross section enlargements 26 and 26′ arranged one behind the other. Further air outlet openings 25′ are hereby arranged between two cross section enlargements 26, 26′, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 034 206.0 | Jul 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/003829 | 6/23/2010 | WO | 00 | 4/2/2012 |
