Method for spinning slivers with spinning stations having jet nozzles in a jet spinning machine to a thread head on the winding side and jet spinning machine

Abstract

In a method for spooling a sliver (2) to a winding side end (3) in a spinning station (4) with a jet (5) in a air jet spinning machine (1), the end (3) is fed back through the jet (5) against the withdrawal direction (AR) of the yarn (15) and brought into contact with the sliver (2). During a spooling phase (8), a withdrawal device (6) is put into operation and spinning air is applied to the jet channel (7) of the jet (5). During a start-up phase (9), the withdrawal speed (v) of the withdrawal device (6) is accelerated to a normal production speed (vP). During the spooling phase (8) and / or the start-up phase (9), the spinning air is set by a spinning air regulating device (12) to an air pressure (p) and / or a volume flow which deviates from a normal spinning air pressure (pSp) or a normal spinning volume flow.

Description

Technical Field

[0001] This invention relates to a method for spinning a sliver end to a winding-side yarn end in a spinning station with a spinneret in an air-jet spinning machine. In this method, the yarn end is fed back through the spinneret against the yarn pull-out direction and brought into contact with the sliver end. During the spinning-out phase, a pull-out device is activated and spinning air is applied to the spinneret orifice of the spinneret so that the sliver end is spun to the yarn end under the action of the airflow within the spinneret. Furthermore, during the start-up phase, the pull-out speed of the pull-out device is accelerated to the normal production speed. Here, the air pressure and / or volumetric flow rate of the pull-out device and the spinning air are controlled by a control unit of the spinning station and / or the air-jet spinning machine. Furthermore, this invention also relates to a corresponding air-jet spinning machine. Background Technology

[0002] In the case of this type of air-jet spinning machine, it is well known that after an interruption in the spinning process, the yarn end on the winding side is fed back through the spinneret against the spinning direction and overlaps with one end of the fed sliver. For example, overlap may occur within the drafting system area or between the drafting system and the spinneret inlet. Subsequently, the feeding of the sliver through the drafting system is restarted in a coordinated manner, and the yarn is pulled out by a take-up device (which may also be formed by the winding device). Similarly, the air supply to the spinneret is restarted in a coordinated manner, thereby causing the sliver end to be spun to the yarn end in the spinneret. Here, the fibers of the fed sliver end are wrapped around the yarn end by the airflow within the spinneret.

[0003] Patent document DE102016118858A1 discloses a method for operating an air-jet spinning machine, wherein the yarn head is assisted by a jet channel that acts in the opposite direction to the spinning direction.

[0004] In this type of air-jet spinning machine, a common problem arises where the splice quality does not match the actual required yarn quality. It is often difficult to firmly connect the leading fibers of the ply to the yarn end, resulting in a decrease in yarn strength within the splice zone. Similarly, yarn quality may also degrade in the area immediately following the actual splice zone. Summary of the Invention

[0005] The purpose of this invention is to provide a method for splicing fiber heads in a spinning station with a spinneret in an air-jet spinning machine, which can improve yarn quality during the splicing process.

[0006] To achieve the above objectives, the present invention provides a method for spinning a sliver end to a winding side yarn end in a spinning station having a spinneret in an air-jet spinning machine, and an air-jet spinning machine having the features described in the independent claims.

[0007] In a method for spinning a sliver end to a winding-side yarn end in a spinning station with a spinneret in an air-jet spinning machine, the yarn end is fed back through the spinneret against the yarn pull-out direction, and the yarn end comes into contact with the sliver end. During the splicing phase, a pull-out device is activated and spinning air is applied to the spinneret orifice of the spinneret so that the sliver end is spun to the yarn end under the action of the airflow within the spinneret. During the start-up phase, the pull-out speed of the pull-out device is accelerated to the normal production speed. In this method, the air pressure and / or volumetric flow rate of the pull-out device and the spinning air are controlled by a control unit of the spinning station and / or the air jet spinning machine.

[0008] The method proposes that, during the spinning stage and / or the start-up stage, the spinning air is set by means of a spinning air conditioning device to deviate from the normal spinning air pressure or the normal spinning volumetric flow rate, wherein the spinning air pressure and / or volumetric flow rate is matched with the current pulling speed of the pulling device.

[0009] Within the scope of this application, "pulling device" refers to a unit or mechanism that triggers the pulling of yarn, which can be either a winding device or a separate pulling device.

[0010] By matching the air pressure and / or volumetric flow rate to the current drawing speed of the drawing device, improved fiber entanglement can be achieved at the joining point and immediately following it, even at slower drawing speeds (such as those encountered during spinning). For example, at the beginning of the spinning stage, increasing the air pressure and / or volumetric flow rate can improve the entanglement of the first few fibers; this process must be completed while the mechanism is still accelerating and the spinning speed is relatively slow. Similarly, by matching the air pressure and / or volumetric flow rate to the current drawing speed of the drawing device, the drawing speed can be intentionally reduced relative to normal spinning operations during spinning, thereby improving the controllability and reliability of spinning. Likewise, by matching the air pressure and / or volumetric flow rate to the drawing speed during the start-up phase, yarn with performance essentially equivalent to normal yarn can be obtained even in the area immediately following the actual joining zone. Specifically, this matching method allows for the acquisition of yarn strength and twist values ​​similar to those of normally produced yarn.

[0011] The same advantages can be achieved using an air-jet spinning machine that includes at least one spinning station (with a spinneret and a take-up device), and this application also claims protection for such an air-jet spinning machine. The spinneret has spinneret orifices for applying spinning air. The air-jet spinning machine has at least one control unit.

[0012] The air-jet spinning machine also includes at least one spinning air conditioning device, and the control unit is configured to control the take-up device and the spinning air conditioning device according to the method.

[0013] Preferably, the initiation phase begins after the spinning phase, but the initiation phase and the spinning phase may overlap in time.

[0014] Advantageously, during the spinning stage, an increased air pressure relative to the normal spinning air pressure and / or an increased volumetric flow rate relative to the normal spinning volumetric flow rate are set. By increasing the kinetic energy input, it is possible to better connect the fibers at the sliver tip, especially the first few fibers of the sliver tip, to the yarn tip on the winding side. It is particularly advantageous here that the increased air pressure is at least 5 bar; more advantageously, the increased air pressure is preferably at most 7 bar. It is also advantageous that the increased air pressure is at most 6 bar. In contrast, the normal spinning air pressure during the normal production stage can be, for example, 4 to 5 bar. It is also conceivable to install an additional compressor in the air-jet spinning machine to provide an increased air pressure relative to the normal spinning air pressure during the spinning stage. This is particularly advantageous because, during the spinning stage, the increased air pressure should be higher than the air supply pressure of the air-jet spinning machine.

[0015] In an air-jet spinning machine, the spinning air conditioning device preferably includes at least one solenoid valve or electro-pneumatic valve. Here, the electro-pneumatic valve can achieve stepless adjustment of air pressure in a particularly advantageous manner. However, the air pressure can also be adjusted in stages using one or more valves.

[0016] To implement the method, it is more advantageous in air-jet spinning machines to have a spinneret orifice diameter greater than 0.6 mm, preferably at least 0.7 mm, and more preferably less than 0.85 mm. In conventional air-jet spinning machines, the orifice diameter is typically at most 0.6 mm, but in this solution, by increasing the orifice diameter, a higher volumetric flow rate can be provided at the same air pressure. Thanks to the increased orifice diameter and volumetric flow rate, it is advantageous to operate at a lower spinning air pressure (e.g., 4 to 5 bar) during normal production, thereby achieving excellent energy savings. In existing air-jet spinning machines, an air pressure of approximately 6 bar is commonly used during normal production, but in this solution, this level of air pressure is only required during the spinning splicing stage and / or the start-up stage.

[0017] Therefore, it is particularly advantageous in the air-jet spinning machine and the method to combine an increased air pressure (compared to the normal spinning air pressure) during the spinning stage with a larger aperture greater than 0.6 mm. This allows the air-jet spinning machine to operate particularly economically.

[0018] It is also advantageous that, during the spinning stage, the pull-out device operates at a reduced spinning speed relative to the normal production speed (preferably constant). Reducing the pull-out speed significantly improves spinning reliability, thereby reducing the risk of yarn breakage and subsequent processing problems. By matching the air pressure and / or volumetric flow rate to the pull-out speed, it is still possible to produce joints with good yarn strength and no obvious thick or thin points.

[0019] Another advantage is that during the start-up phase, the drawing device can be accelerated or increased from a reduced splicing speed to the normal production speed. By matching the air pressure and / or volumetric flow rate with the drawing speed, yarns with performance essentially equivalent to those produced during the normal production phase can be produced in the area immediately following the splice or connection zone.

[0020] At the end of the spinning stage, the increased air pressure relative to the normal spinning air pressure and / or the increased volumetric flow rate relative to the normal spinning volumetric flow rate are reduced, wherein the reduced air pressure and / or reduced volumetric flow rate are lower than the normal spinning air pressure and / or normal spinning volumetric flow rate. This allows the air pressure to be well matched to the current draw-out speed during the subsequent start-up phase. This limits the increased air pressure relative to the normal spinning air pressure to the direct spinning process within the spinneret, where the increased air pressure promotes fiber entanglement at the sliver end.

[0021] Another advantage is that during the start-up phase, as the take-up speed gradually increases, the air pressure and / or volumetric flow rate increase from a reduced level to the normal spinning air pressure and / or normal spinning volumetric flow rate. This allows the air pressure to be well matched to the current take-up speed during the start-up phase.

[0022] According to a first embodiment of the method, it is advantageous to reduce and / or increase air pressure and / or volumetric flow rate in a stepped manner. This allows for particularly simple control of air pressure without the need for complex adjustment techniques, thereby reducing the cost of the spinning apparatus and even the overall cost of the air-jet spinning machine.

[0023] According to another advantageous embodiment of the method, the air pressure and / or volumetric flow rate are continuously decreased and / or increased. This requires a slightly more complex control system for the spinning air conditioning.

[0024] A particular advantage here is that the air pressure and / or volumetric flow rate can be dynamically adjusted to decrease and / or increase based on the current extraction speed. This allows the air pressure to be precisely matched to the current extraction speed.

[0025] The advantage of this method lies in the input to the control unit of: the level and / or grade and / or amplitude of increasing air pressure and / or increasing volumetric flow rate and / or decreasing air pressure and / or decreasing volumetric flow rate; and / or the level of decreasing spinning speed; and / or the duration of increasing air pressure; and / or the duration of decreasing air pressure; and / or the duration of the spinning phase; and / or the duration of the start-up phase. Correspondingly advantageously in the air-jet spinning machine is that the above parameters can be selected and input into the control unit. Thus, for example, the optimal values ​​of the above parameters can be determined based on empirical values ​​for each application and according to the normal spinning air pressure. Subsequently, the parameters of the air-jet spinning machine can be automatically set by the control unit. Attached Figure Description

[0026] Further advantages of the present invention will be described below with reference to embodiments. In the figures: Figure 1 A schematic frontal overview of an air-jet spinning machine is shown; Figure 2 A schematic partial cross-sectional side view of the spinning station of an air-jet spinning machine during normal production operation is shown. Figure 3 A schematic partial cross-sectional side view of the spinning station of an air-jet spinning machine after a disruption of normal production operation is shown. Figure 4 A schematic partial cross-sectional side view of the spinning station of an air-jet spinning machine during the spinning process is shown. Figure 5 A schematic diagram of the air pressure change curve of the spinning station of the air jet spinning machine according to the first embodiment during the spinning process is shown. Figure 6 A schematic diagram of the take-up speed variation curve of the spinning station of the air jet spinning machine according to the first embodiment during the spinning process is shown. Figure 7 A schematic diagram of the air pressure versus take-up speed variation curves of the spinning station of the jet spinning machine according to the second embodiment is shown. Figure 8 A schematic diagram of the air pressure versus take-up speed variation curves of the spinning station of the air jet spinning machine according to the third embodiment is shown. Figure 9 A schematic diagram of the air pressure versus take-up speed variation curves of the spinning station of the air jet spinning machine according to the fourth embodiment is shown. Figure 10 A schematic diagram of the air pressure versus take-up speed variation curves of the spinning station of the air jet spinning machine according to the fifth embodiment is shown. Figure 11 A schematic cross-sectional view of the spinneret is shown.

[0027] Figure Labels 1: Air-jet spinning machine; 2: Sliver head; 3: Yarn head; 4: Spinning station; 5: Spinneret; 6: Pull-out device; 7: Spinneret orifice; 8: Spinning stage; 9: Start-up stage; 10: Production stage; 11: Control unit; 12: Spinning air (generator) regulating device; 13: Frame; 14: Sliver; 15: Yarn; 16: Drafting system; 17: Winding device; 18: Winding cylinder; 19: Sliver inlet; 20: Air supply channel; 21: Spindle; 22: Spinneret body; 23: Compressed air generator; 24: Air supply line; 25: Through channel; AR: Pull-out direction; v: Pull-out speed; vA: Spinning speed; vP: Production speed; p: Air pressure; pSp: Normal spinning air pressure; pl: Decrease air pressure; ph: Increase air pressure; t: Time. Detailed Implementation

[0028] In the following description of embodiments, features that are identical or at least equivalent in design and / or function are labeled with the same reference numerals. Furthermore, these features are described in detail only upon their first mention, and subsequent embodiments primarily illustrate the differences from previous embodiments. Unless these features are described in detail again, their design and / or function correspond to the design and function of the aforementioned features. Additionally, for clarity, only one or a few of the multiple identical components or features are typically labeled.

[0029] Figure 1 A schematic front view of an air-jet spinning machine 1 is shown. The air-jet spinning machine 1 employs a known method of juxtaposing several spinning stations 4 between two frames 13. These spinning stations 4 have multiple mechanisms for producing yarn 15. At each spinning station 4, a sliver 14 is fed from a storage container (not labeled) into a drafting system 16, where the sliver 14 is drafted. The drafted sliver is then fed into a spinneret 5, where it is spun into yarn 15 by means of an airflow. In this example, the produced yarn 15 is then pulled out of the spinneret 5 by a drawing device 6 and fed into a winding device 17, where the yarn 15 is wound onto a winding bobbin 18. Alternatively, the yarn 15 can be directly drawn out by the winding device 17. The air-jet spinning machine 1 also has a compressed air generator 23, which supplies compressed air to the spinning stations 4 via an air supply line 24. Furthermore, a control unit 11 is provided to control the operation of the air-jet spinning machine 1. In this example, each spinning station 4 also has its own control unit 11, which is connected to the control unit 11 of the air-jet spinning machine 1. It is understood that this is merely an example, and the number and implementation of the control units can be varied or supplemented in many ways, such as group control units, segmented control units, etc.

[0030] Figure 2A schematic partial cross-sectional side view of the spinning station 4 of the air-jet spinning machine 1 during normal production operation is shown. Unlike... Figure 1 The overall view, and the spinneret orifice 7 of the spinneret 4, are also visible in this cross-sectional view. It can also be seen that the spinning station 4 has a dedicated spinning air conditioning device 12. The spinning air conditioning device 12 may include one or more valves for opening or closing and / or adjusting the compressed air supplied via the air supply line 24. During normal production operation, the fed sliver 14 reaches the spinneret 5 through the drafting system, where it is twisted by the airflow generated through the spinneret orifice 7, and then spun into yarn 15. Spinning air is applied to the spinneret orifice 7 by the spinning air conditioning device 12.

[0031] Figure 3 A schematic partial cross-sectional side view of the spinning station 4 of the air-jet spinning machine 1 after a disruption in normal production operation is shown. Such a disruption may occur, for example, after a yarn breakage or cleaning cut. Depending on the cause of the disruption, the yarn end 3 on the winding side is located on the surface of the winding cylinder 18 or in the yarn run area above the spinneret 5. In this example, the yarn end 3 remains within the pull-out device 6 or, with respect to the pull-out direction AR, remains before the pull-out device 6. The sliver end 2 is located at the outlet of the drafting system 16.

[0032] Figure 4 A schematic partial cross-sectional side view of the spinning station 4 of the air-jet spinning machine 1 during the splicing process is shown. In order to splice the sliver end 2 to the winding-side yarn end 3, the winding-side yarn end 3 must first be fed back through the spinneret 5 against the normal take-up direction AR until it exits the spinneret 5 again from the sliver inlet 19. For this process, please refer to [reference needed]. Figure 4 Next, in the subsequent spinning process, the drafting system 16 is activated, thereby introducing the sliver head 2 into the sliver inlet 19 region. Similarly, the take-up device 6 and / or the winding device 17 are activated, and spinning air is applied to the spinneret orifice 7 of the spinneret 5 in a time-coordinated manner by means of the spinning air conditioning device 12. The winding side yarn head 3 and the sliver head 2 thus enter the working area of ​​the spinneret orifice 7 and connect with each other under the action of the airflow within the spinneret 5.

[0033] In order to produce yarn segments of constant and identical or nearly identical quality in the joining area and / or immediately following area of ​​yarn 15, according to the present invention, the air pressure p and / or volumetric flow rate of the spinning air are matched with the current drawing speed v of the drawing device 6, as follows: Figures 5 to 10 As stated above.

[0034] Figure 5A schematic diagram is shown illustrating the change of air pressure p over time t during the spinning process of the spinning station 4 of the air-jet spinning machine 1 according to the first embodiment. The horizontal axis represents the two stages of the spinning process: spinning stage 8 and start-up stage 9, and production stage 10 or normal operation. The vertical axis represents the air pressure p of the spinning air. According to this example, during spinning stage 8, an increased air pressure ph is set relative to the normal spinning air pressure pSp. This process is particularly useful for better attaching and integrating the first few fibers of the sliver head 2 to the yarn head 3 by enhancing the airflow. This is especially important because actual spinning often occurs with a sudden start to the pull and a relatively slow pull speed v, which is detrimental to reliable fiber entanglement. This can be avoided by inputting more kinetic energy during spinning stage 8. Once the sliver head 2 is spun to the yarn head 3, the air pressure p is reduced to the normal spinning air pressure p, and this normal spinning air pressure p is also maintained during normal production stage 10. This increased air pressure p during the spinning stage remains advantageous regardless of changes in the pull speed v.

[0035] In this example, during startup phase 9, the air pressure p of the spinning air is matched to the normal spinning air pressure pSp. During splicing phase 8, the air pressure p is only briefly increased, so the air-jet spinning machine 1 will still operate in an energy-saving mode. If a spinneret 5 with enlarged spinneret orifices 7 is additionally used, such as... Figure 11 As shown, it is even possible to achieve higher energy-saving effects compared to the air-jet spinning machine 1 or existing spinning methods. For example, the increased air pressure ph during the spinning stage 8 can be 5 to 6 bar, while the normal spinning air pressure pSp can be, for example, 4 to 5 bar due to the enlargement of the spinneret orifice 7.

[0036] In comparison, Figure 6 An exemplary diagram illustrates the variation curve of the take-up speed v of the spinning station 4 of the air-jet spinning machine 1 during the spinning process according to the first embodiment. According to this example, during the spinning stage 8, the take-up device 6 operates at a reduced spinning speed vA relative to the normal production speed vP. For example, the take-up speed v during the spinning stage 8 can reach 8300 m / min, while the normal production speed vP can be, for example, 550 m / min to 600 m / min. Reducing the spinning speed vA can improve spinning reliability, but at the same time, the yarn strength of the splice may be insufficient, which may lead to yarn breakage and subsequent processing problems. In the prior art, the spinning process commonly uses a higher take-up speed v within the range of the normal production speed vP. As shown, if the spinning stage 8 operates at a reduced spinning speed vA, the increased air pressure p during the spinning stage 8 (e.g., ...) Figure 5 (As shown) It has a very positive impact on yarn quality, especially splice strength.

[0037] According to this example, in the startup phase 9 following the spinning stage 8, the take-up speed v continuously increases from the spinning speed vA to the normal production speed vP. During startup phase 9, the air pressure p of the spinning air (e.g., ...) Figure 5 (As shown) can correspond to the normal spinning air pressure pSp.

[0038] Figure 7 A schematic diagram showing the variation curves of air pressure p versus take-up speed v at spinning station 4 of the air-jet spinning machine 1 according to the second embodiment is shown. The variation trend of the spinning speed vA basically corresponds to... Figure 6 The graph shown.

[0039] During the spin-bonding stage 8 (such as Figure 5 As shown, an increased air pressure ph is provided to improve fiber entanglement in the splicing zone. However, near the end of the splicing stage 8, the increased air pressure ph relative to the normal spinning air pressure pSp briefly drops to a reduced air pressure pl, which is lower than the normal spinning air pressure pSp. For example, after the splicing is completed, the reduced air pressure pl immediately drops to 3.5 bar to 4 bar, and then increases to the normal spinning air pressure pSp along with the pull-out speed v.

[0040] In this way, even during the subsequent start-up phase 9, the air pressure p can be matched with the current drawing speed v. As shown in the figure, as the drawing speed v gradually increases, the air pressure p also rises from a decrease in air pressure pl until it reaches the level of the normal spinning air pressure pSp at the end of start-up phase 9. If the air pressure p and the drawing speed v are matched, the yarn segment immediately following the splice or joint (which is formed during the start-up phase) can also produce yarn with the same quality and strength characteristics as the yarn produced during normal production.

[0041] In order to match the air pressure p with the current pull speed v, each spinning station 4 is preferably provided with a spinning air conditioning device 12, which preferably includes a dynamic pressure regulating device, such as one or more electro-pneumatic valves.

[0042] During the start-up phase, the air pressure p can be controlled or adjusted in a manner proportional to the extraction speed v or according to other functions, and can also be adjusted continuously or in stages (see below). Figures 8 to 10 (Detailed explanation).

[0043] Figure 8 A schematic diagram showing the variation curves of air pressure p versus take-up speed v at spinning station 4 of the air-jet spinning machine 1 according to the third embodiment is shown. Spinning stage 8 is similar. Figure 7The air pressure p increases relative to the normal spinning air pressure pSp. Similarly, at the end of the start-up phase 8, the air pressure p decreases to the reduced air pressure pl; while during the start-up phase 9, the air pressure p increases at the same magnitude as the take-up speed v, so the two curves appear to be parallel.

[0044] Figure 9 A schematic diagram showing the variation curves of air pressure p versus take-up speed v at spinning station 4 of the air-jet spinning machine 1 according to the fourth embodiment is shown. Spinning stage 8 is similar. Figure 5 The air pressure p increases relative to the normal spinning air pressure pSp. At the end of the spinning stage 8, the air pressure p also decreases to the reduced air pressure p1. Referring to this figure, this change is step-like, but it may also be stage-like depending on the adjustment scheme (e.g., ...). Figure 10 (as shown) or in a continuous manner (such as) Figure 7 and Figure 8 (As shown).

[0045] During Phase 9 of the launch, such as Figure 7 and Figure 8 As shown, the air pressure p rises from the reduced air pressure pl to the normal spinning air pressure pSp. This differs from... Figure 7 and Figure 8 This speed increase is not continuous, but rather staged. This simplifies the design of the spinning air conditioning device 12. Needless to say, for easier adjustment, the actual number of stages can be fewer than shown in this figure. Furthermore, each stage need not be equidistant or have the same duration.

[0046] Figure 10 A schematic diagram showing the variation curves of air pressure p versus take-up speed v at spinning station 4 of the air-jet spinning machine 1 according to the fifth embodiment is shown. Unlike Figure 9 Only at the end of spinning stage 8, the air pressure p is not continuous but graded, decreasing from increasing air pressure ph to decreasing air pressure pl. In this diagram, the process is completed in two stages, but more or fewer stages can also be set.

[0047] at last, Figure 11 A schematic simplified cross-sectional view of the spinneret 5 is shown. The spinneret 5 has a spinneret body 22 in a known manner, in which a spindle 21 and a through-passage 25 for the produced yarn 15 are arranged. Furthermore, a sliver inlet 19 can be seen in the lower region of the spinneret 5. The spinneret 5 also has spinneret orifices 7, thereby applying spinning air pressure p to the air supply passage 20.

[0048] According to an advantageous embodiment of the invention, the diameter of the spinneret orifice 7 is greater than 0.6 mm, which corresponds to the commonly used orifice diameter of a conventional spinneret 5. Particularly advantageously, the orifice diameter is at least 0.7 mm. This allows for a higher volumetric flow rate in the spinneret 5 under the same pressure, which in turn enables better entanglement of the fibers of the sliver 14 into the yarn 15. This enlarged orifice diameter of the spinneret orifice 7 enables better operation during normal production phase 10 (see...). Figures 5 to 10 Spinning is performed at a lower spinning air pressure pSp compared to a conventional air-jet spinning machine 1. The spinning air pressure pSp in a conventional air-jet spinning machine 1 is about 6 bar, but the spinneret 5 with enlarged spinneret orifice 7 can operate at a significantly lower normal spinning air pressure pSp compared to the prior art, for example, in the range of 4.5 bar to 5 bar.

[0049] For example, the increased air pressure (pH) during spinning stage 8 can reach 6 bar. This means that the compressed air generator 23 only needs to generate a maximum pressure of 6 bar, as in the prior art, so that even if the air pressure is increased during spinning stage 8, the air consumption can still be kept at a low level.

[0050] Figures 5 to 10 The curve showing the change in pull speed v versus air pressure p is merely an example. It is particularly advantageous that at least some of the relevant parameters can be set, for example, by inputting these parameters on the control unit 11 of the air-jet spinning machine 1 (see...). Figure 1 Particularly advantageously, the level of reducing the spinning speed vA and / or the duration of the spinning stage 8 and / or the duration of the start-up stage 9 can be selected (preferably freely selected) and input to the control unit 11. This also applies to the duration of increasing the air pressure ph and / or the duration of reducing the increased air pressure ph to the reduced air pressure pl. According to an embodiment of the spinning air conditioning device 12, it is even more advantageous to select and input to the control unit 11 the level and / or number and / or amplitude of increasing the air pressure ph and / or decreasing the air pressure pl.

[0051] Figures 5 to 10 Although only the air pressure p change curve is depicted, this also applies to the volumetric flow rate change curve. According to the implementation scheme of spinning station 4 (especially compressed air conditioning device 12), even if the air pressure p of spinning air remains unchanged, the volumetric flow rate can still be changed accordingly, for example, by releasing different cross-sectional areas of the spinning air supply area during the spinning process or during spinning stage 8, start-up stage 9 and production stage 10.

[0052] In addition, unlike Figures 5 to 10 As shown, the initiation stage 9 can also overlap with the spinning stage 8 in time, wherein the initiation stage 9 can also begin from the point where the spinning stage 8 has already started.

[0053] This invention is not limited to the embodiments shown in the figures and described herein. The combination of features represented and described in different embodiments may also be covered within the scope of the claims.

Claims

1. A method for spinning a sliver end (2) to a winding-side yarn end (3) in a spinning station (4) having a spinneret (5) in an air-jet spinning machine (1), wherein the yarn end (3) is fed back through the spinneret (5) against the pull-out direction (AR) of the yarn (15), and the yarn end (3) is brought into contact with the sliver end (2). in, During the spinning stage (8), the pull-out device (6) is put into operation and spinning air is applied to the spinneret orifice (7) of the spinneret (5) so that the sliver head (2) is spun to the yarn head (3) under the action of the airflow in the spinneret (5). During the startup phase (9), the extraction speed (v) of the extraction device (6) is accelerated to the normal production speed (vP). The take-up device (6) and the air pressure (p) and / or volumetric flow rate of the spinning air are controlled by the control unit (11) of the spinning station (4) and / or the air jet spinning machine (1). Its features are, During the spinning stage (8) and / or the start-up stage (9), the spinning air is set by the spinning air conditioning device (12) to deviate from the normal spinning air pressure (pSp) or normal spinning volume flow rate, wherein the air pressure (p) and / or volume flow rate of the spinning air is matched with the current pull speed (v) of the pull-out device (6).

2. The method according to the preceding claim, characterized in that, During the spinning stage (8), the increased air pressure (ph) of the spinning air relative to the normal spinning air pressure (pSp) and / or the increased volumetric flow rate relative to the normal spinning volumetric flow rate are set, wherein preferably, the increased air pressure (ph) is at least 5 bar, and / or wherein preferably, the increased air pressure (ph) is at most 7 bar.

3. The method according to the preceding claim, characterized in that, The diameter of the spinneret orifice (7) of the spinneret (5) is greater than 0.6 mm, preferably at least 0.7 mm, and preferably less than 0.85 mm.

4. The method according to any one of the preceding claims, characterized in that, During the spinning stage (8), the pull-out device (6) operates at a reduced spinning speed (vA) that is preferably constant relative to the normal production speed (vP).

5. The method according to any one of the preceding claims, characterized in that, During the start-up phase (9), the pulling device (6) accelerates from the reduced spinning speed (vA) to the normal production speed (vP).

6. The method according to any one of the preceding claims, characterized in that, At the end of the spinning stage (8), the increased air pressure (ph) of the spinning air relative to the normal spinning air pressure (pSp) and / or the increased volumetric flow rate of the spinning air relative to the normal spinning volumetric flow rate are reduced. Wherein, the reduction of air pressure (psp) and / or the reduction of volumetric flow rate is lower than the normal spinning air pressure (pSp) and / or the normal spinning volumetric flow rate.

7. The method according to the preceding claim, characterized in that, During the start-up phase (9), as the pull-out speed (v) gradually increases, the air pressure (p) and / or the volumetric flow rate increases from the reduced air pressure (pl) and / or the reduced volumetric flow rate to the normal spinning air pressure (pSp) and / or the normal spinning volumetric flow rate.

8. The method according to any one of the preceding claims, characterized in that, The air pressure (p) and / or the volumetric flow rate are reduced and / or increased in stages.

9. The method according to any one of the preceding claims, characterized in that, The decrease and / or increase of the air pressure (p) and / or the volumetric flow rate are carried out continuously.

10. The method according to any one of the preceding claims, characterized in that, Input to the control unit (11) the level and / or grade and / or amplitude of the increased air pressure (ph) and / or the increased volumetric flow rate and / or the decreased air pressure (pl) and / or the decreased volumetric flow rate; and / or the level of the decreased spinning speed (vA); and / or the duration of the increased air pressure (ph); and / or the duration of reducing the increased air pressure (ph) to the decreased air pressure (pl); and / or the duration of the spinning stage (8); and / or the duration of the start-up stage (9).

11. An air-jet spinning machine (1), comprising: At least one spinning station (4) has a spinneret (5) and a take-up device (6). The spinneret (5) has a spinneret channel (7) for applying spinning air; and At least one control unit (11). Its features are, The jet spinning machine (1) and / or the spinning station (4) have at least one spinning air conditioning device (12); and The control unit (11) is configured to control the pulling device (6) and the spinning air conditioning device (12) according to any one of the preceding claims.

12. The air-jet spinning machine (1) according to claim 11, characterized in that, The spinning air conditioning device (12) includes at least one solenoid valve or electro-pneumatic valve.

13. The air-jet spinning machine (1) according to any one of the preceding claims, characterized in that, The diameter of the spinneret orifice (7) of the spinneret (5) is greater than 0.6 mm, preferably at least 0.7 mm, and preferably less than 0.85 mm.

14. The air-jet spinning machine (1) according to any one of the preceding claims, characterized in that, The following can be selected and input into the control unit (11): the level and / or grade and / or amplitude of the increase in air pressure (ph) and / or the increase in volumetric flow rate and / or the decrease in air pressure (pl) and / or the decrease in volumetric flow rate; and / or the level of the decrease in spinning speed (vA); and / or the duration of the increase in air pressure (ph); and / or the duration of the decrease in air pressure (ph) to the decrease in air pressure (pl); and / or the duration of the spinning stage (8); and / or the duration of the start-up stage (9).

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