Method for optimizing the production of a rotor spinning machine

Abstract

A method optimizes production of a rotor spinning machine having a plurality of identical spinning units, with each spinning unit having a spinning rotor driven by a rotor drive at a rotor speed to produce yarn at a delivery speed. A permissible range with a minimum delivery speed and a maximum delivery speed for the delivery speed of the spinning units is specified. Operation of the spinning units is started with a starting delivery speed within the permissible range. Current production capacity of the spinning units or the rotor spinning machine is continuously calculated. Current delivery speed of the yarn is regulated as a function of the current production capacity in such a manner that a maximum production capacity is achieved. A rotor spinning machine in accordance with method is also provided.

Claims

1. A method for optimizing production of a rotor spinning machine having a plurality of identical spinning units, with each spinning unit having a spinning rotor, and wherein during operation of the rotor spinning machine, the spinning rotors are driven by a rotor drive, rotate at a rotor speed, and provide a yarn at a delivery speed, the method comprising: specifying a permissible range with a minimum delivery speed and a maximum delivery speed for the delivery speed of the spinning units; starting operation of the spinning units with a starting delivery speed within the permissible range; continuously monitoring and calculating current energy consumption of the spinning units or the rotor spinning machine; regulating current delivery speed as a function of the current energy consumption in such a manner that a minimum energy consumption is achieved, comprising decreasing the delivery speed from the starting delivery speed until the minimum energy consumption is reached and only increasing the delivery speed when the minimum delivery speed has been reached or an increase in energy consumption results from operation at the decreased delivery speed.

2. The method according to claim 1, further comprising: continuously calculating current production capacity of the spinning units or the rotor spinning machine; and regulating current delivery speed also as a function of the current production capacity, wherein one or more of the following are used for calculating the current production capacity: current thread breakage rate, current clearer cut rate, current maintenance intervention rate, and maintenance capacity.

3. The method according to claim 2, wherein the rotor spinning machine is operated to achieve one of: a maximum production capacity, the minimum energy consumption, or a weighted partial optimum of the maximum production capacity and the minimum energy consumption.

4. The method according to claim 2, wherein a desired production capacity range is specified with an upper and a lower production capacity limit, and the current delivery speed is regulated within the desired production capacity range to achieve the minimum energy consumption.

5. The method according to claim 2, wherein a desired energy consumption range is specified with an upper and a lower energy consumption limit, and the current delivery speed is regulated within the desired the desired energy consumption range to achieve a maximum production capacity.

6. The method according to claim 1, wherein for the regulating the current delivery speed, a speed of the rotor and the delivery speed are adjusted to maintain yarn properties unchanged.

7. The method according to claim 1, wherein the permissible range of the delivery speed is determined based on one or more of: a maximum permissible rotor speed; desired yarn quality requirements; and climatic conditions of the spinning environment.

8. The method according to claim 1, wherein the delivery speed and rotor speed are separately set and adjusted for each rotor drive of the rotor spinning machine.

9. The method according to claim 8, wherein each spinning unit comprises an individual drive for the rotor and an individual drive for the draw-off device, wherein the delivery speed and the rotor speed are individually set for each spinning unit.

10. The method according to claim 2, wherein setting options for one or both of the production capacity and the energy consumption are indicated, and wherein the rotor spinning machine is operated in accordance with selection or value of the setting options.

11. A rotor spinning machine, comprising: a plurality of spinning units, each spinning unit comprising: a spinning rotor with a rotor drive wherein the spinning rotor is driven with a variable rotor speed during operation of the rotor spinning machine; a draw-off device by which a produced yarn is removed from the spinning unit at a delivery speed; wherein a current energy consumption of the spinning units or the rotor spinning machine is continuously calculated; a control unit configured to regulate the delivery speed within a permissible range having a minimum delivery speed and a maximum delivery speed based on the current energy consumption in a manner such that a minimum energy consumption is achieved; and wherein the control unit is configured to regulate current delivery speed as a function of the current energy consumption in such a manner that a minimum energy consumption is achieved by decreasing the delivery speed from the starting delivery speed until the minimum energy consumption is reached and only increasing the delivery speed when the minimum delivery speed has been reached or an increase in energy consumption results from operation at the decreased delivery speed.

12. The rotor spinning machine according to claim 11, wherein a current production capacity of the spinning units or the rotor spinning machine is continuously calculated, the control unit further regulating current delivery speed also as a function of the current production capacity, wherein one or more of the following are used for calculating the current production capacity: current thread breakage rate, current clearer cut rate, current maintenance intervention rate, and maintenance capacity.

13. The rotor spinning machine according to claim 12, wherein the control unit regulates the delivery speed to achieve one of: a maximum production capacity, a minimum energy consumption, or a weighted partial optimum of the maximum production capacity and the minimum energy consumption.

14. The rotor spinning machine according to claim 12, wherein a desired production capacity range and a desired energy consumption range are stored in the control unit such that the spinning units are controlled to be within the stored production capacity range with the minimum energy consumption or within the stored energy consumption range with the maximum production capacity.

15. The rotor spinning machine according to claim 12, further comprising indicator by which setting options for one or both of the production capacity and the energy consumption are displayed, and an input by which the setting options are selected or changed.

16. The rotor spinning machine according to claim 11, wherein each spinning unit comprises an individual drive for the spinning rotor and an individual drive for the draw-off device, wherein the delivery speed and the rotor speed are individually set for each spinning unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages are described on the basis of the following presented embodiments. The following is shown:

(2) FIG. 1 is a rotor spinning machine according to a first design in a schematic top view; and

(3) FIG. 2 is a schematic sectional view of a spinning unit of a rotor spinning machine according to a second design.

DETAILED DESCRIPTION

(4) 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.

(5) FIG. 1 shows a rotor spinning machine 1 with a multiple number of spinning units 2 arranged side by side, each having a spinning rotor 3 as a spinning element. Here, a fiber material 16 (see FIG. 2), which is opened into individual fibers in a opening device 9 and fed to the spinning rotor 3, is fed to the spinning units 2 in a conventional manner by means of a feed device 8. The yarn 15 produced in the spinning rotor 3 is subsequently drawn off by a draw-off device 10 at a delivery speed and fed via a yarn monitoring device 6 to a winding device 11, where it is wound onto a coil 17.

(6) In order to drive the spinning rotors 3, according to the design of FIG. 1, a central rotor drive 4 is provided that, by means of a tangential belt 18, drives the spinning rotors 3 of a multiple number of spinning units 2 in a group-by-group manner. In this case, a single rotor drive 4 can be provided for all spinning units 2 of the spinning machine 1, a separate rotor drive 4 can be provided for each side of the rotor spinning machine 1, or the spinning units 2 of the rotor spinning machine 1 can also be divided into groups, each of which is then assigned with a separate rotor drive 4. Furthermore, the rotor spinning machine 1 features a drive 14 for the draw-off devices 10 which, like the rotor drive 4, can be provided as a central drive for all spinning units 2 of the rotor spinning machine or for a group of spinning units 2 of the rotor spinning machine 1. Furthermore, one or more maintenance devices 12, which can be moved on a rail 13, are provided on the rotor spinning machine 1 and carry out maintenance operations at the spinning units 2, such as the repair of thread breaks, thread setting after clearer cuts, coil changing, rotor cleaning and the like.

(7) The rotor spinning machine 1 has a control and/or regulating unit 5, which drives the rotor drive(s) 4 and the drive(s) 14 of the draw-off devices 10 along with additional drives, which are not designated here. The control and/or regulating unit 5 is connected to the maintenance device 12 for controlling or regulating the elements of the maintenance device 12, as indicated by the dash-dotted line. With the present invention, the control and/or regulating unit 5 is provided as a central control and/or regulating unit 5 of the rotor spinning machine 1, and is connected to an additional control and/or regulating unit 5 of the maintenance device 12. However, the maintenance device 12 could likewise be controlled by the central control and/or regulating unit 5 of the rotor spinning machine 1. Furthermore, the control and/or regulating unit 5, which works together with the control and/or regulating unit 5 of the rotor spinning machine 1 and/or the maintenance devices 12, may also feature the individual spinning units 2.

(8) If a thread breakage occurs during the operation of the rotor spinning machine 1, this is registered by the yarn monitoring device 6, the further feeding of the fiber material 16 to the relevant spinning unit 2 is stopped, and the removal of the thread breakage by the maintenance device 12 is initiated. Since the relevant spinning unit 2 does not produce any additional yarn 15 until the thread breakage is corrected, the production capacity of the spinning machine 1 is thereby reduced. The same problem arises if the quality problems of the produced yarn 15 are determined by the yarn monitoring device 6, and a clearer cut is then initiated. Likewise, by means of further maintenance activities of the maintenance device 12, such as coil changing, rotor cleaning, and the like, standstill times of spinning units 2, which have negative effects on production capacity, arise. The problem of reduced production capacity is aggravated even if only a few maintenance devices 12 are present, or if many maintenance requests exist at the same time, resulting in long waiting times at the individual spinning units 2. In addition, not all of the maintenance requests can be remedied by the maintenance devices 12; rather, intervention by an operator is often required.

(9) With the present rotor spinning machine 1, it is therefore provided that the spinning units 2 are not operated at a predetermined, constant delivery speed; rather, the current delivery speed is adjusted as a function of the current production capacity, in such a manner that maximum production capacity is achieved. Means 22 are provided for this purpose, by means of which the current production capacity can be continuously calculated during operation. For this purpose, a corresponding formula is stored in the rotor spinning machine 1, which is used to constantly calculates the current yarn production on the basis of the current delivery speed, the current thread breakage rate, a current clearer cut rate, and a current maintenance capacity or a current maintenance intervention rate. The delivery speed is then always tracked within a previously defined, permissible range starting from a starting delivery speed, in such a manner that maximum production capacity is achieved.

(10) In order to be able to calculate the current production capacity on the basis of the indicated factors, means 19 are provided on the rotor spinning machine 1 in the area of the yarn monitoring device 6, with which the thread breakage rate of the relevant spinning unit 2 can be determined. If the yarn monitoring device 6 is additionally equipped with a yarn cleaning device, the means 19 are also designed to detect a clearer cut rate. In the maintenance device 12, means 21 are also provided, by means of which a maintenance intervention rate can be determined on the rotor spinning machine 1. Thereby, the maintenance intervention rate can be determined as a total maintenance intervention rate for the entire rotor spinning machine 1 or also separately for each individual spinning unit 2. Furthermore, the maintenance capacity can be stored in the control and/or regulating unit 5 of the rotor spinning machine 1 and, if necessary, can also be detected during changes such as, for example, upon the removal of a maintenance device 12 or personnel breaks. The control and/or regulating unit 5 of the rotor spinning machine 1 furthermore has means 21 that, based on the aforementioned data along with the values of the means 18 for determining the thread breakage rate and/or the clearer cut rate along with the means 20 for determining the maintenance intervention rate, determine the current production capacity of the rotor spinning machine 1 on the basis of the stored formula.

(11) The control and/or regulating unit 5 thereupon regulates the current delivery speed by means of the drive 14 in such a manner that maximum production capacity is achieved. This may mean that the delivery speed will be increased if the current production capacity has decreased with respect to a production capacity that was already determined. However, this can also mean that the current delivery speed is reduced if, after an increase in the delivery speed, a drop in production capacity has nevertheless occurred.

(12) According to the present example, the current thread breakage rate, the current clearer cut rate, the current maintenance intervention rate, and the maintenance capacity were used to calculate the current production capacity. However, it is, of course, also possible to use other factors for calculating the current production capacity, such as, for example, a wear condition of the spinning rotors along with standstill times, for which corresponding means for detecting the wear state 19 (see FIG. 2), and means for detecting standstill times are provided. Preferably, not only is the current delivery speed tracked; rather, the rotational speed of the spinning rotors 3 is simultaneously adjusted, such that the yarn twist of the yarn 15 produced remains constant. For this purpose, the control and/or regulating unit 5 is capable of driving the drive 14 of the draw-off devices 10 along with the rotor drive 4 at a variable rotational speed.

(13) FIG. 2 shows a spinning unit 2 of an additional design of a rotor spinning machine 1, with which the spinning rotors 3, along with the draw-off devices 10, are not driven by means of central drives, but by means of individual drives. The same components of the spinning unit 2 of FIG. 2 are provided with the same reference signs as in FIG. 1, such that only the differences with the design of FIG. 1 will be discussed in the following. As already explained, each of the spinning rotors 3 of FIG. 2 is driven by means of a rotor drive 4, which is arranged at the spinning unit 2 and designed as an individual drive. Likewise, the draw-off devices 10 are driven by means of a drive 14, which is designed as an individual drive. Furthermore, the means 19 for determining a thread breakage rate and/or a clearer cut rate are shown in the present sectional view of the spinning units 2.

(14) In contrast to the rotor spinning machine 1 of FIG. 1, with the present rotor spinning machine 1, each of the individual spinning units 2 is provided with a maintenance device 12 of its own spinning unit, which is at least able to remedy thread breaks or to spin in again after clearer cuts. Preferably, the maintenance device 12 of its own spinning unit also includes a separate device for rotor cleaning and, if necessary, a separate device for changing the coil. The maintenance device 12 also includes means 21 for determining the maintenance intervention rate in the respective spinning unit 2. In addition, means 20 for determining a wear state of the spinning rotor 3 are arranged at the shown spinning unit 2.

(15) With such a rotor spinning machine 1, it is possible to individually detect the current production capacity for each spinning unit 2, and to optimize it individually at each spinning unit 2 by a corresponding tracking of the delivery speed. The specified means 19, 20, 21 are in turn connected to a control and/or regulating unit 5, which is advantageously provided at each individual spinning unit. The control and/or regulating unit 5 in turn has means 21 for calculating the production capacity, and is able to drive the rotor drive 4 along with the drive 14 of the draw-off device 10, in such a manner that maximum production capacity is always achieved. However, instead of the control and/or regulating unit 5 of its own spinning unit shown here, the control of the drives 4, 14 and the calculation of the production capacity can, of course, also take place in a central control and/or regulating unit 5 of the rotor spinning machine 1. Furthermore, the maintenance capacity of the spinning machine 1 can also be stored in a central control and/or regulating unit 5 and, if appropriate, can be currently detected. Of course, it would also be conceivable to detect the current production capacity or the current energy consumption in each case in a group-by-group manner for a multiple number of spinning units 2, and to control the drives of the spinning machine 1 preferably also in a group-by-group manner, or to provide group drives.

(16) With each of the described designs, it is advantageous if the spinning machine 1 includes indicator means and input means, such that the various available setting options can be indicated to the operator and he is able to select them. The indicator means and input means can be provided, for example, within the control unit 5.

(17) The invention is not limited to the illustrated embodiments. In particular, for example, hybrid forms of the rotor spinning machines 1 shown in FIGS. 1 and 2 are also possible. For example, although rotor drives 4 may be provided as individual drives, as shown in FIG. 2, the maintenance, as in FIG. 1, can be carried out by means of movable maintenance devices 12. Additional variations and combinations within the framework of the claims also fall under the invention.

LIST OF REFERENCE SIGNS

(18) 1 Rotor spinning machine 2 Spinning units 3 Spinning rotor 4 Rotor drive 5 Control and/or regulating unit 6 Yarn monitoring device 7 Frame 8 Feed device 9 Severing device 10 Draw-off device 11 Winding device 12 Maintenance device 13 Rail 14 Drive of the draw-off devices 15 Yarn 16 Fiber material 17 Coil 18 Tangential belt 19 Means for determining the thread breakage rate and/or clearer cut rate 20 Means for determining the wear state of the spinning rotor 21 Means for determining the maintenance intervention rate 22 Means for calculating the current production capacity