Spinning unit of an air jet spinning machine and its operation

Abstract

A spinning unit is provided for an air jet spinning machine with a spinning nozzle used to manufacture yarn from a fiber strand. The spinning nozzle has an inlet for the fiber strand, a vortex chamber, a yarn forming element protruding into the vortex chamber, and a draw-off channel for the yarn. An additive supply is assigned to the spinning nozzle and designed so that the spinning nozzle is supplied with an additive. The yarn forming element has at least one additive duct that ends in the vortex chamber or the draw-off channel. The additive supply encompasses an additive supply line connected to the additive duct so that an additive introduced into the additive duct via the additive supply line can be introduced into the draw-off channel and/or the vortex chamber. A process for operating an air jet spinning machine with at least one spinning unit is provided. An additive is added, at least intermittently, to the spinning nozzle of the spinning unit while it is operating with the help of an additive supply. The added additive is delivered through an additive duct of the yarn forming element to the draw-off channel and/or the vortex chamber.

Claims

1. A spinning unit for an air jet spinning machine, comprising: a spinning nozzle configured to manufacture yarn from a fiber strand, the spinning nozzle further comprising: an inlet for the fiber strand; an internally located vortex chamber; a yarn forming element protruding into the vortex chamber and having a yarn draw off channel for the yarn; and an outlet for the produced yarn; an additive supply in communication with the spinning nozzle to supply the spinning nozzle with an additive; the yarn forming element further comprising at least one additive duct defined therein that ends in the vortex chamber or the draw off channel, the additive duct oriented obliquely relative to a transport direction of the yarn through the draw off channel; and the additive supply further comprising at least one additive supply line that is fluidically connected to the additive duct, so that an additive introduced through the additive supply line into the additive duct is introduced into one or both of the draw off channel or the vortex chamber.

2. The spinning unit according to claim 1, wherein the additive duct comprises a bore that runs inside the yarn forming element.

3. The spinning unit according to claim 2, wherein the additive duct defines an angle (a) with an axis of the draw-off channel between 3 and 12.

4. The spinning unit according to claim 2, wherein the additive duct ends in the draw-off channel adjacent to a fiber inlet opening in the yarn forming element.

5. The spinning unit according to claim 2, characterized in that the additive duct ends in an outer surface of a wall of the yarn forming element that surrounds the draw-off channel.

6. The spinning unit according to claim 1, characterized in that the additive duct is also fluidically connected with a compressed air line so that compressed introduced air introduced via the compressed air line is introduced into one or both of the draw-off channel or the vortex chamber through the additive duct.

7. The spinning unit according to claim 6, further comprising a valve in either of the compressed air line or the additive supply line, the valve settable between two different valve positions such that the additive duct is fluidically connected either to the compressed air line or the additive supply fine depending on the position of the valve.

8. The spinning unit according to claim 7, wherein the valve is connected to a control mechanism designed to keep the valve, during spinning operation of the spinning unit, in a first valve position in which the additive duct is fluidically connected to the additive supply line, and to keep the valve, during a piecing process of the spinning unit, in a second valve position in which the additive duct is fluidically connected to the compressed air line.

9. A process for operating an air jet spinning machine with at least one spinning unit having a spinning nozzle, comprising: feeding a fiber strand to the spinning nozzle via an inlet while the spinning unit is operated; imparting a twist to the fiber strand proximate to a yarn forming element that protrudes into a vortex chamber of the spinning nozzle, wherein a yarn is formed from the fiber strand and exits the spinning nozzle through a draw-off channel of the yarn forming element; with an additive supply, feeding an additive to the spinning nozzle while the spinning unit is operated; and wherein the additive is fed through an additive duct defined in the yarn forming element and is delivered in one or both of the draw-off channel or the vortex chamber, the additive duct oriented obliquely relative to a transport direction of the yarn through the draw off channel.

10. The process according to claim 9, wherein an additive is delivered through the additive duct during a spinning process of the spinning unit, and compressed air is delivered through the additive duct during a piecing process of the spinning unit.

11. The process according to claim 10, wherein the additive duct is fluidically connected to an additive supply line and a compressed air line, and a valve is assigned to one of the additive supply line or the compressed air line, wherein the valve is controlled in a first position during the spinning process in which the additive duct is connected to the additive supply line, and wherein the valve is controlled in a second position during the piecing process in which the additive duct is connected to the compressed air line.

12. The process according to claim 9, wherein volumetric or mass flow of the additive delivered via the additive duct is regulated with a dosing device.

13. The process according to claim 12, wherein the volumetric flow of the delivered additive reaches a rate between 0.001 mlmL/min and 7.0 mL/min, or mass flow of the delivered additive reaches a rate between 0.001 g/min and 7.0 g/min.

14. The process according to claim 13, wherein the volumetric flow of the additive delivered while the spinning unit is operating in a spinning process reaches a rate between 0.001 mL/min and 1.5 mL/min, and the volumetric flow of the additive added while the spinning unit is being cleaned reaches a rate between 2.0 mL/min and 7.0 mL/min.

15. The process according to claim 13, wherein the mass flow of the additive delivered while the spinning unit is operating in a spinning process reaches a rate between 0.001 g/min and 1.5 g/min, and the mass flow of the additives added while the spinning unit is being cleaned reaches a rate between 2.0 g/min and 7.0 g/min.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages of the inventions are described in the following embodiments, which show:

(2) FIG. 1 a section of a spinning unit of an air jet spinning machine,

(3) FIG. 2 another section of a spinning unit of an air jet spinning machine,

(4) FIG. 3 a yarn forming element of a spinning unit according to the invention,

(5) FIG. 4 another embodiment of a yarn forming element of a spinning unit according to the invention,

(6) FIG. 5 another embodiment of a yarn forming element of a spinning unit according to the invention, and

(7) FIG. 6 a schematic diagram of a section of an air jet spinning machine with a spinning unit according to the invention.

DETAILED DESCRIPTION

(8) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(9) FIG. 1 shows a section of a spinning unit of an air jet spinning machine according to the invention (needless to say, the air jet spinning machine can have many spinning units preferably arranged next to one another). If necessary, the air jet spinning machine can encompass a drafting system 20 with several drafting system rollers 19 (which can be partially entwined with an apron 28) delivered with a fiber strand 3 in form of a doubled draw frame sliver. Furthermore, the spinning unit shown in more detail in FIG. 2 encompasses a spinning nozzle 1 with a vortex chamber 5 arranged inside, in which the fiber strand 3 or at least some of the fibers of the fiber strand 3 are imparted a twist after passing an inlet 4 of the spinning nozzle 1 (the precise mode of action of the spinning nozzle 1 will be described in more detail below).

(10) In addition, the air jet spinning machine can encompass a pair of draw-off rollers downstream from the spinning nozzle 1 with two draw-off rollers 26 and a winding device 27 downstream from the draw-off roller pair for spooling the yarn 2 that leaves the spinning unit on a tube. The spinning unit according to the invention must not necessarily have a drafting system 20. The draw-off roller pair is not absolutely necessary either.

(11) The shown spinning unit works generally according to an air spinning process. To form the yarn 2, the fiber strand 3 is guided with a fiber guiding element 18 through an inlet opening of the inlet 4 mentioned above into the vortex chamber 5 of the spinning nozzle 1, where a twist is imparted to it, i.e. at least a few of the free fiber ends of the fiber strand 3 are grasped by the vortex air flow generated by air nozzles 22 arranged in a vortex chamber wall surrounding the vortex chamber 5 (the air nozzles 22 can be connected to one another by means of an air supply duct 23 that is, in turn, connected to a compressed air line 25 supplied with compressed air via a compressed air supply 29; compare also FIG. 6 and the associated description).

(12) Here, some of the fibers are pulled out of the fiber strand 3, at least to some extent, and wound around the front area of a yarn forming element 6 protruding into the vortex chamber 5. Owing to the fact that the fiber strand 3 is drawn from the spinning nozzle 1 through a fiber inlet opening 32 of the yarn forming element 6 via a draw-off channel 24 arranged inside the yarn forming element 6 from the vortex chamber 5 and finally through an outlet 7 from the spinning nozzle 1, the free fiber ends are finally also pulled towards the fiber inlet opening 32 and in the process twist as so-called wrap fibers around the centrally running core fibersresulting in a yarn 2 having the desired twist. The compressed air introduced through the air nozzles 22 finally comes out of the spinning nozzle 1 through the draw-off channel 24 and a possibly present air outlet 21, which can be connected to a negative pressure source if necessary.

(13) Generally speaking, it should be clarified here that the manufactured yarn 2 can be basically any fiber strand 3 characterized by the fact that an outer portion of the fibers (the so-called wrap fibers) twists around an inner, preferably untwisted or if necessary twisted portion of the fibers in order to impart the yarn 2 with the desired strength. Thus, the invention also encompasses an air jet spinning machine used to manufacture so-called rove. The rove is a yarn 2 having a relatively low proportion of wrap fibers or a yarn 2 in which the wrap fibers are twisted relatively loosely around the inner core so that the yarn 2 remains capable of being drafted. This becomes decisive when the manufactured yarn 2 should or must be drafted once again in a subsequent textile machine (e.g. a ring spinning machine) with the help of a drafting system be muss so it can be correspondingly processed further.

(14) With regard to the air nozzles 22, it should be mentioned here from a purely precautionary viewpoint that they should generally be aligned in such a way that the air jets emerge with equal alignment in order to generate together an air flow with equal alignment and a direction of rotation. Preferably, the individual air nozzles 22 are here arranged rotationally symmetrical to one another and end tangentially in the vortex chamber 5.

(15) According to the invention, FIG. 6 depicts that an additive supply 8 is assigned to the spinning unit that encompasses one or several additive deposits 9 (for example in form of a pressure container having the additive and a gaseous pressure medium) to provide the additive and one or several, preferably at least partially flexible, additive supply lines 14, through which the corresponding additive deposit 9 is fluidically connected to an additive duct 10 (regarding possible additives, please consult the description given so far).

(16) It is furthermore intended for the additive duct 10 mentioned above to extend at least partially inside the yarn forming element 6, in which case the additive duct 10 can be present as a bore, for example. As can be seen in FIG. 3 regarding this, the additive duct 10 can end in the draw-off channel 24 starting from a connection 30 (which is, in turn, fluidically connected to the additive supply line 14), in which case the transition from additive duct 10 in the draw-off channel 24 is arranged preferably in the area of the fiber inlet opening 32 of the yarn forming element 6. Additionally, the angle between the draw-off channel 24 and the additive duct 10 (merely identified in FIG. 3) should have the magnitude mentioned in the general description. An additive introduced to this area through the additive duct 10 makes contact with the fibers of the yarn 2, thereby improving the quality of the yarn properties (strength, hairiness, etc.). If the quantity of the additive is increased accordingly during the cleaning operation of the spinning nozzle 1, then the additive also reaches the area of the outer surface 13 of the yarn forming element 6 (due to the negative pressure that prevails in the vortex chamber 5) and brings about its cleaning.

(17) Alternately to the embodiment shown in FIG. 3, it is likewise conceivable for the outlet opening 15 of the additive duct 10 to be arranged in the area of the outer surface 13 of the yarn forming element 6 mentioned above, in which case the additive duct 10 is arranged preferably too in a wall 12 of the yarn forming element 6 that surrounds the draw-off channel 24 (see FIG. 4). In this case also, the additive makes contact with the fibers entering the draw-off channel 24 and in addition very reliably reaches the area of the outer surface 13 of the yarn forming element 6.

(18) FIG. 5 shows another embodiment of a possible yarn forming element 6. The yarn forming element 6 shown there has several parts, contrary to the one shown in FIGS. 3 and 4. In particular, the yarn forming element 6 encompasses a base body 33 and a tip 34 connected with it (that can be detached, for example). Accordingly, the additive duct 10 also encompasses several sections, in which case a ring-shaped duct 35 can be present in the transitional area between base body 33 and tip 34 to ensure that the sections of the additive duct 10 mentioned above are always fluidically connected regardless of a relative twisting of base body 33 and tip 34.

(19) Finally, FIG. 6 shows a schematic diagram of a section of an air jet spinning machine according to the present invention. As can be seen in this diagram, it is conceivable for a first (in FIG. 6: lower) compressed air line 25 to be present that is connected, on the one hand, with a compressed air supply 29 of the spinning machine and, on the other hand, with the air nozzles 22 of the spinning nozzle 1, as shown in FIG. 2. Finally, the individual air nozzles 22 can be impinged with compressed air via this compressed air line 25 during the spinning operation.

(20) Furthermore, an additive deposit 9 is present, connected fluidically to the connection 30 of the additive duct 10 (shown in FIGS. 3 to 5) through an additive supply line 14, in which case the additive supply line 14 can encompass a dosing device 17 so the volumetric and/or mass flow of the added additive can be regulated (to achieve this, the dosing device 17 can be connected to the control device 16 to allow an automated control).

(21) Additionally, another compressed air line 25 can be present (in FIG. 6: the compressed air supply 29 exiting upwards) that can also be fluidically connected to the connection 30 shown in FIGS. 3 to 5. In this case, the additive duct 10 can also be impinged with compressed air so the piecing process can be carried out.

(22) So it can be determined whether the additive duct 10 can be supplied with compressed air or additive, it finally makes sense to equip the additional compressed air line 25 and the additive supply line 14 with a valve 11 that allows, depending on its setting, a delivery of additive or compressed air to the common supply line 31 that branches off from the valve 11 (in this case, the supply line 31 can be connected to the above-mentioned connection 30). Finally, the control mechanism 16 is used preferably to set the valve position.

(23) The present invention is not restricted to the embodiments shown and described. Modifications within the framework of the invention are just as possible as any combination of the characteristics described, even if they are shown and described in different parts of the description or claims or in different embodiments.