Method for detecting a leak and / or a blockage in a spinning unit of a spinning device of a rotor spinning machine or an air-jet spinning machine

Abstract

The present invention relates to a method for detecting leakage and / or blockage in the spinning unit of a spinning apparatus of a rotor spinning machine or an air-jet spinning machine, and to a rotor spinning machine or air-jet spinning machine for performing the method. To provide a method for reliably detecting leaks and / or blockages in the spinning units of a rotor spinning machine or an air-jet spinning machine, and a rotor spinning machine or air-jet spinning machine for performing the method, the method is specified to include the following steps: - setting the spinning machine to an inspection mode, wherein a compressed air valve is specifically set to an "open" state in a controllable manner to release a compressed air flow feed to the spinning units; - if at least one compressed air source is cut off, turning on the compressed air source to feed the compressed air flow; - closing the compressed air valves one after another in a defined sequence, wherein each time a compressed air valve is closed, a dominant compressed air flow value is measured, and the measurement result is transmitted to an evaluation device and assigned to at least one spinning unit assigned to the compressed air valve, and compared with a specified limit value or limit range stored in the evaluation device or a memory unit connected to the evaluation device; - the evaluation device identifies spinning units whose assigned compressed air flow values ​​deviate from the limit values ​​or limit ranges, wherein it is assessed whether the measured compressed air flow value is below or above the assigned limit values ​​or limit ranges.

Description

[0001] The present invention relates to a method for detecting leakage and / or blockage in the spinning unit of a spinning apparatus of a rotor spinning machine or an air-jet spinning machine, and to a rotor spinning machine or air-jet spinning machine for performing the method.

[0002] Known rotor spinning machines or air-jet spinning machines include at least one section having a defined number of spinning units, each spinning unit having a spinning unit that requires an airflow to process the yarn fed to the respective spinning unit into yarn during the spinning process. The airflow is typically generated by at least one source of compressed air. Depending on the type of spinning machine, this can be either a suction air system or a source of compressed air, particularly used with rotor spinning machines to generate, for example, a spinning negative pressure, or particularly used with air-jet spinning machines to generate spinning pressure.

[0003] Therefore, the spinning rotor of a rotary spinning machine can be considered as a spinning unit, and the rotor cups are supplied with suction air during normal spinning operation and during the initial spinning process. In the case of an air-jet spinning machine, the air spinneret can be considered as a spinning unit. A spinning unit is generally any device designed to pneumatically generate yarn from the fibers of a sliver (either individually or as a sliver).

[0004] To supply the spinning units of each spinning apparatus, they are each connected to a compressed air supply line, such that compressed air from at least one compressed air source can be fed to the assigned spinning unit via the compressed air supply line. The compressed air flow fed to the respective spinning apparatus can be regulated via a switchable (and particularly controllable) compressed air valve assigned to each spinning unit. To monitor the compressed air flow, at least one compressed air flow meter (such as a mass flow transmitter or a volumetric flow transmitter) is used to measure the compressed air flow rate within the compressed air supply line.

[0005] For the quality of yarn produced by a rotor spinning machine or an air-jet spinning machine, the compressed air flow (especially the accompanying pressure, negative pressure, or volumetric flow) must be within a defined range so that the spinning unit can properly process the yarn or individual fibers of the yarn. Providing the compressed air flow directly after the corresponding request (if possible) also maximizes the machine's productivity, since the spinning unit would otherwise have to spend unproductive waiting time. On the other hand, setting the size of the compressed air source that generates the compressed air flow to meet the maximum required compressed air flow demand disadvantageously increases its cost.

[0006] Similarly, maintaining the compressed air flow higher than currently required increases energy consumption. This may be necessary, for example, if there are losses within the compressed air flow path, such as due to leaks. Further losses in the quality of the produced yarn can be caused by blockages in the air nozzles of the spinning unit, which can also lead to a complete interruption of the yarn production process.

[0007] It is known in the prior art to determine the corresponding compressed air volume flow at each spinning unit in order to identify leaks and / or blockages in each spinning unit of the spinning unit. However, since this method has considerable inaccuracies, the object of the present invention is to provide a method for reliably detecting leaks and / or blockages in the spinning units of a rotor spinning machine or an air-jet spinning machine, and a rotor spinning machine or air-jet spinning machine for performing the method.

[0008] For the purposes of this invention, compressed air flow is understood to mean an air flow generated by negative or positive pressure, wherein the direction of air flow in a portion of the compressed air supply line is determined by the arrangement of the pressure or negative pressure source. Therefore, in the direction of air flow, an air flow generated by negative pressure may be different from or the same as an air flow generated by pressure, depending on its arrangement. A rotor spinning machine or an air-jet spinning machine has at least one section having a defined number of spinning units, each having a spinning cell. At least one compressed air source is allocated to the spinning units, which is connected to a compressed air supply line that conducts the compressed air flow. To supply compressed air to the individual spinning units, they are connected, in particular, to the compressed air supply line via compressed air flow branch pipes, wherein the compressed air supply line or compressed air flow branch pipes are each used to supply to the individual spinning cells of the spinning units. A control and regulation unit is coupled to the spinning machine to control and / or regulate at least one compressed air source and corresponding switchable (particularly controllable) compressed air valves allocated to the spinning cells to regulate the compressed air flow fed to the allocated spinning cells. Furthermore, the spinning machine is equipped with an evaluation device for assessing measurements from at least one compressed air flow meter (such as a mass flow transmitter or a volumetric flow transmitter) used to measure the compressed air flow rate within the compressed air supply line. The evaluation device assesses the measurement data transmitted by the compressed air flow meter. The compressed air flow value that can be determined by the compressed air flow meter is at least the compressed air volumetric flow through the compressed air supply line or the dominant air pressure in the compressed air supply line.

[0009] A control and regulation unit and an evaluation device are used to perform the method according to the invention, wherein the spinning apparatus is inspected for leaks and / or blockages in the spinning unit. For this purpose, the spinning machine is first set to an inspection mode in which the compressed air valves are, in particular, controllably set to an "open" state to release a compressed air flow feed to the spinning unit. In a subsequent method step, if at least one compressed air source is in a cut-off state, the compressed air source is turned on to feed a compressed air flow. The compressed air valves are then closed one after another in a defined sequence, particularly in a controllably manner, wherein each time a compressed air valve is closed, a dominant compressed air flow value is measured, and the measurement result is transmitted to the evaluation device and assigned to the corresponding spinning unit, and compared with a specified limit range stored in or connected to a memory unit of the evaluation device. After the comparison, the evaluation device then identifies spinning units whose assigned compressed air flow values ​​deviate from the limit values ​​or limit ranges, wherein the identification enables the evaluation of whether the measured compressed air flow value is below or above the assigned limit values ​​or limit ranges. Specifically, the spinning apparatus, spinning unit, and / or compressed air supply lines associated with unacceptable deviations are indicated by means of a display unit. This means that deviations can not only be handled within the system, as will be described in more detail below by way of example, but are also visualized for the operator. Furthermore, the degree of deviation relative to the assigned limit value or limit range can preferably be identified by an evaluation device, and especially indicated by means of a display unit.

[0010] The method according to the invention has the advantage that, when the corresponding compressed air valves assigned to the spinning unit are closed one after another in a defined sequence, the differential volumetric flow or pressure difference obtained by comparing the compressed air flow values ​​before and after the valve closure is used as a measurement to identify leaks and / or blockages in the spinning unit. Because, for example, the total volumetric flow can be detected with a higher relative accuracy than the individual volumetric flow at the corresponding spinning unit, leaks and / or blockages can be detected in a particularly reliable manner. The method can be performed such that, after inspecting the spinning unit, the corresponding compressed air valve is reopened, particularly in a controllable manner, and then the next compressed air valve is closed, particularly in a controllable manner, in a specified defined sequence. Furthermore, the method according to the invention can also be performed such that the compressed air valve remains in the closed position after the measurement has been performed, and then the next compressed air valve in that sequence is subsequently closed, particularly in a controllable manner.

[0011] The compressed air source, evaluation equipment, and / or control and regulation unit may preferably be included in the rotor spinning machine or air-jet spinning machine. Alternatively, the compressed air source, evaluation equipment, and / or control and regulation unit may be arranged separately from the rotor spinning machine or air-jet spinning machine and operatively connected to said machine. A feature of the invention is that a compressed air flow meter is provided for measuring the compressed air flow rate within the compressed air supply line and is connected to the evaluation equipment in a data transmission manner, wherein the data transmission can generally be implemented in a conventional manner, particularly in a wired or wireless manner, as needed.

[0012] In the process of the method according to the invention, a compressed air flow meter is used, for example, via measurement data of the dominant total volumetric flow after the individual compressed air valves are closed, transmitted to an evaluation device, to reliably identify spinning units with leaks and / or blockages. Differential volumetric flow exceeding a limit value or range after the compressed air valves are closed indicates a leak in the assigned spinning unit, while differential volumetric flow below the limit value or range indicates a blockage in the spinning unit.

[0013] The comparison and evaluation of the determined compressed air flow value with the limiting value or limit range is performed by the evaluation device. In the sense of this invention, the evaluation device is understood as a functionally interacting element or unit configured to perform the desired process. The element or unit may be implemented separately from each other or in a common assembly. The evaluation device is preferably integrated into a processor-supported device, such as a control and regulation unit assigned to a rotor spinning machine or air-jet spinning machine. Particularly advantageously, the control and regulation unit is connected to the evaluation device via data transmission. This connection enables the automated execution of an inspection mode in which the individual spinning units of the spinning apparatus are checked for leaks and / or blockages. This process can be reliably executed by the control and regulation unit in a processor-controlled manner without operator intervention.

[0014] An alarm signal can be activated according to a preferred embodiment of the invention once the assessment shows an unacceptable deviation of the compressed air flow value from the limit value or the limit range. The alarm signal is activated when the assessment device transmits a signal suitable for triggering the alarm signal, for example, directly to the unit that triggers the alarm signal or to an intermediate unit. The alarm signal can be a visual, optical, acoustic, and / or tactile signal. Using such an alarm signal, the operator of the rotary spinning machine or air-jet spinning machine can be informed of incorrect operation that may lead to poor yarn quality.

[0015] The proposed method is a cost-effective and highly reliable way to detect leaks and / or blockages in the spinning unit of a rotor spinning machine or air-jet spinning machine. The process of measurement, transmission, determination, comparison, and evaluation can preferably be performed periodically or at fixed points in time, depending on energy consumption requirements, wherein the rotor spinning machine or air-jet spinning machine is set to a check mode for this purpose, making it possible to implement the method according to the invention. The more frequently such a process is performed, the higher the corresponding energy demand of the rotor spinning machine or air-jet spinning machine may be, but the more reliable the monitoring and immediate intervention or fault diagnosis becomes, thereby optimizing the productivity of the rotor spinning machine or air-jet spinning machine and improving the quality of the produced yarn.

[0016] According to a preferred embodiment, the alarm signal includes not only information about leaks and / or blockages, but also information about which spinning unit, spinning gear, compressed air supply line, and / or compressed air flow branch line is affected. The corresponding display of information, except for the type of unacceptable deviation (i.e., whether it is a blockage or a leak), allows for the correction of existing leaks and / or blockages in a particularly targeted manner and under temporary notification, enabling the rotor spinning machine or air-jet spinning machine to operate at a high level of overall productivity.

[0017] A particularly advantageous configuration involves, upon detection of a leak and / or blockage, the switchable (especially controllable) compressed air valve assigned to the identified spinning unit remaining in the closed position, or, if the compressed air valve is open, moving to the closed position if a deviation in the compressed air flow value at the relevant spinning unit is deemed unacceptable. This configuration of the invention reliably ensures that the corresponding spinning unit ceases operation until the detected defect is corrected, thereby reliably preventing the generation of defective yarn.

[0018] According to a particularly advantageous configuration of the invention, the method proposed in this invention is suitable for an air-jet spinning machine, wherein the spinning unit is composed of an air-jet spinneret, by means of the air-jet spinneret forming yarn from the fed yarn through an air nozzle of compressed air fed to the air-jet spinneret, the air nozzle generating a vortex airflow within the air-jet spinneret.

[0019] According to another aspect of the invention, a rotor spinning machine or air-jet spinning machine is provided for performing the method according to the invention or the method according to one of the preferred embodiments. The rotor spinning machine or air-jet spinning machine has:

[0020] - At least one section, the at least one section comprising a defined number of spinning devices, each spinning device having a spinning unit.

[0021] -At least one source of compressed air

[0022] - Compressed air supply lines, each of which is coupled to at least one spinning unit in the spinning unit, wherein compressed air flow from the at least one compressed air source can be fed to the at least one spinning unit assigned to it via the compressed air supply lines.

[0023] - A switchable, and particularly controllable, compressed air valve assigned to at least one spinning unit, wherein the compressed air valve is designed to maintain at least a constant pressure regardless of the pressure volume flow, and particularly to control the flow of compressed air supplied.

[0024] - At least one compressed air flow meter, which is used to measure the flow rate of compressed air in a compressed air supply line.

[0025] A rotor spinning machine or air-jet spinning machine according to the invention for performing the method or improved method according to the invention is characterized in that it has or is coupled to:

[0026] - A control and regulation unit, coupled to at least one compressed air source and a compressed air valve, for controlling and / or regulating at least one compressed air source and a corresponding compressed air valve, and

[0027] - An evaluation device that connects to the compressed air flow meter via data transmission for evaluating measurement data from the compressed air flow meter.

[0028] The evaluation device is configured to compare the dominant compressed air flow value during each, particularly controllable, closure of the compressed air valves as they are closed in a defined sequence with a specified limit value or limit range stored in the evaluation device or a memory unit connected to the evaluation device, and to identify spinning units whose assigned compressed air flow values ​​deviate from the limit value or limit range, wherein the evaluation determines whether the measured compressed air flow value is below or above the limit value or limit range.

[0029] The rotor spinning machine or air-jet spinning machine according to the invention is characterized by allowing for the identification of spinning units with leaks and / or blockages in a particularly simple and reliable manner, enabling the faults to be corrected under temporary notification if necessary, thereby ensuring high productivity of the rotor spinning machine and air-jet spinning machine. Furthermore, it reliably avoids the production of yarn of poor quality.

[0030] According to a particularly advantageous configuration of the invention, compressed air valves, provided for blocking the compressed air flow to the assigned spinning unit, are arranged in a compressed air flow branch duct via which the assigned spinning unit is connected to a compressed air supply line to guide the compressed air flow. This corresponding arrangement of the compressed air valves reliably ensures that the corresponding spinning unit or spinning device is isolated from the compressed air source. Therefore, according to a particularly preferred embodiment, a plurality of compressed air valves included in a rotary spinning machine or an air-jet spinning machine, or according to another preferred embodiment, all compressed air valves included in a rotary spinning machine or an air-jet spinning machine, can be arranged in corresponding compressed air flow branch ducts.

[0031] According to another configuration of the invention, the control and regulation unit is further connected to the evaluation device via data transmission. This configuration of the invention makes it possible to perform method steps in inspection mode via the evaluation device in an automated manner, for example, in a process-controlled manner, for detecting leaks and / or blockages, without operator intervention.

[0032] According to another preferred embodiment, the evaluation device is connected to the display unit wirelessly or via wired means for data transmission, as exemplarily described above, and is designed to enable the display unit to indicate the spinning apparatus, spinning unit, pressure supply line, compressed air flow branch pipe related to deviations and / or degrees of deviation relative to limit values ​​or limit ranges. In this way, the degree of deviation is visualized to the operator.

[0033] Exemplary embodiments of the invention are explained below with reference to the accompanying drawings. In the drawings:

[0034] Figure 1 It is a schematic diagram of the implementation scheme of the spinning machine, and

[0035] Figure 2 This is a schematic flowchart of an implementation scheme for a method of detecting leaks and / or blockages in the spinning unit of a spinning machine.

[0036] Figure 1 A schematic diagram of a spinning machine 1 is shown, which has multiple spinning devices 3, shown only partially here, which are combined to form sections and each has a spinning unit 4. The spinning devices 3 can be spinning devices of a rotor spinning machine or an air-jet spinning machine.

[0037] The spinning machine 1 includes a frame with a control housing 2 at one end of the machine. A plurality of spinning units 3 extend in a row along the longitudinal side of the spinning machine 1 from the control housing, wherein each spinning unit 3 is connected on a data transmission side to a central control and adjustment unit 14 shown in the control housing 2. Each spinning unit 3 has a spinning unit 4 for producing yarn from a sliver provided at the respective spinning unit 3.

[0038] The spinning machine 1 includes a compressed air source 6 that generates a compressed air flow and is arranged within a control housing 2. The compressed air source 6 is configured to generate a compressed air flow caused by negative or positive pressure. The compressed air source 6 is connected to a compressed air supply line 8 to guide the compressed air flow, wherein a plurality of compressed air flow branch pipes 9 branching from the compressed air supply line 8 are arranged on the compressed air supply line. Each of the branch compressed air flow branch pipes 9 leads to the spinning device 3 and to the spinning units 4 assigned to the spinning device 3, so as to supply them with a compressed air flow that can be generated by the compressed air source 6.

[0039] In the compressed air supply line 8, between the compressed air source 6 and the compressed air flow branch duct closest to the compressed air source 6, the compressed air supply line 8 has a compressed air flow meter 10 for measuring the compressed air flow value (i.e., compressed air volume flow in this exemplary embodiment), which is arranged in the control housing 2 according to the preferred exemplary embodiment shown. The compressed air flow meter 10 is accessible through a maintenance valve in the control housing 2 and is visible, in particular, through an observation window integrated in the maintenance valve. According to the preferred exemplary embodiment, the compressed air flow meter 10 may have a display for calibration and / or digital display of the measurable compressed air volume flow passing through.

[0040] In the corresponding compressed air flow branch pipe 9 leading to the spinning device 3, a switchable, and particularly controllable, compressed air valve 12 is arranged between the compressed air supply line 8 and the spinning unit 4. This compressed air valve is adjustable between an open and closed position, and particularly in a controlled manner. In the open position, compressed air can flow through the corresponding compressed air flow branch pipe 9 via the compressed air valve 12, while the corresponding compressed air flow branch pipe 9 is blocked from flowing compressed air when the compressed air valve 12 is in the closed position.

[0041] The evaluation device 13 is directly connected to the compressed air flow meter 10 and indirectly connected to the compressed air valves 12 of each spinning unit 3 via the control and regulation unit 14. This allows the measured compressed air volume flow to be transmitted from the compressed air flow meter 10 to the evaluation device 13. The control and regulation unit 14 can also be used to adjust the corresponding compressed air valves 12 between open and closed positions, particularly in a controllable manner. Although in Figure 1 The schematic diagram shows only a unidirectional data transmission path, but according to another preferred exemplary embodiment, it can also be a bidirectional connection, so as to provide or retrieve corresponding feedback.

[0042] The evaluation device 13 is configured to detect leaks and / or blockages in the spinning unit 4 of the spinning apparatus 3 during an inspection mode executed by the control and regulation unit 14. The method 100 for detecting leaks and / or blockages in the spinning unit 4 includes: in a first step 110, setting the spinning machine to an inspection mode in the control and regulation unit 14, wherein, in the inspection mode, the compressed air valves 12 of each spinning apparatus 3 are specifically set to an open position in a controllable manner to release a compressed air flow feed to the spinning unit 4.

[0043] In the next step 120, if the compressed air source 6 is in the configured state, the compressed air source is activated or switched on. In the following step 130 related to the testing process, the control and regulation unit 14, in particular, controls and adjusts the compressed air valves 12 on each spinning unit 3 one after another to the closed position in a controlled manner and in a defined sequence, and then records the compressed air volume flow determined on the compressed air flow meter 10 in each case. This measurement is assigned to the corresponding spinning unit 4 and compared in the evaluation device 13 with a specified limit value or limit range, which is stored in the evaluation device 13 or in a memory unit (not shown here) connected to the evaluation device 13.

[0044] If the evaluation device 13 detects a deviation of the compressed air flow value determined by the compressed air flow meter 10 from the assigned limit value or limit range, this is identified by the evaluation device 13 in subsequent step 140, which assesses whether the measured compressed air value exceeds or falls below the stored limit value or limit range, and in particular assesses the degree of deviation relative to the limit value or limit range. The degree of exceeding or falling below, especially the degree of deviation relative to the limit value or limit range, is indicated by the evaluation device 13 via a display unit 15, which is designed as an alarm signal display unit.

[0045] The alarm signal display unit 15 provides information about the type of deviation, wherein a measured compressed air flow value below the limit value or within the limit value range is signaled as a blockage of the spinning unit 4, while a compressed air flow value exceeding the limit value or within the limit value range is indicated on the alarm signal display unit 15 as a leak at the spinning unit 4.

[0046] List of reference numerals

[0047] 1 Spinning machine

[0048] 2. Control Housing

[0049] 3 Spinning apparatus

[0050] 4 Spinning Unit

[0051] 6 Compressed air source

[0052] 8 Compressed air supply lines

[0053] 9. Compressed air flow branch pipe

[0054] 10 Compressed Air Flow Meter

[0055] 12 Compressed air valve

[0056] 13. Evaluation equipment

[0057] 14 Control and Regulation Unit

[0058] 15 display units

[0059] 100 methods

[0060] 110. Steps for setting to inspection mode

[0061] 120. Steps for connecting the compressed air source

[0062] 130 Methods and steps for closing, transmitting, and comparing

[0063] 140 Identification Methods and Steps

Claims

1. A method (100) for detecting leakage and / or blockage in the spinning unit (4) of the spinning device (3) of a rotor spinning machine or air-jet spinning machine (1). -The spinning machine (1) mentioned therein includes - At least one section, said at least one section comprising a defined number of spinning devices (3), each spinning device having a spinning unit (4). - At least one compressed air source (6). - Compressed air supply lines (8), each of which is coupled to at least one of the spinning units (4), wherein the compressed air flow from the at least one compressed air source (6) can be fed via the compressed air supply lines (8) to the at least one spinning unit (4) allocated to the compressed air supply lines. - A switchable compressed air valve (12), said compressed air valve being assigned to at least one spinning unit (4), wherein said compressed air valve (12) is designed to maintain at least a constant pressure regardless of the pressure volume flow. - At least one compressed air flow meter (10), said at least one compressed air flow meter being used to measure the compressed air flow rate within the compressed air supply line (8), -The spinning machine (1) mentioned herein includes or is coupled to, - A control and regulation unit (14), coupled to the at least one compressed air source (6) and the compressed air valve (12), for controlling and / or regulating the at least one compressed air source (6) and the corresponding compressed air valve (12), and - Evaluation device (13), which is connected to the compressed air flow meter (10) via data transmission for evaluating measurement data from the compressed air flow meter (10). -The method (100) described herein includes the following steps: - Set the spinning machine (1) (110) to inspection mode, in which the compressed air valve (12) is set to "open" state so as to release compressed air flow to the spinning unit (4). - If the at least one compressed air source (6) is in a cut-off state, then the compressed air source (6) is switched on (120) to feed a compressed air flow. - The compressed air valves (12) are closed one after another in a defined order, wherein each time a compressed air valve (12) is closed, the dominant compressed air flow value is measured, and the measurement result is transmitted to the evaluation device (13) and assigned to the at least one spinning unit (4) assigned to the compressed air valve (12), and compared with a specified limit value or limit value range stored in the evaluation device (13) or a memory unit connected to the evaluation device (13). -The spinning unit (4) whose assigned compressed air flow value deviates from the limit value or limit range is identified by the evaluation device (13), wherein the evaluation determines whether the assigned compressed air flow value is below or above the limit value or limit range.

2. The method (100) according to claim 1, characterized in that, The control and regulation unit (14) is connected to the evaluation device (13) via data transmission.

3. The method (100) according to claim 1, characterized in that, When the assessment indicates that the assigned compressed air flow value deviates from the limit value or the limit range in an unacceptable manner, the assessment device (13) issues an alarm signal.

4. The method (100) according to claim 3, characterized in that, The alarm signal includes information about the type of the disallowed deviation and about the spinning device (3), the spinning unit (4), and / or the compressed air supply line (8) associated with the disallowed deviation.

5. The method (100) according to any one of claims 1 to 4, characterized in that, When the deviation of the allocated compressed air flow value at the relevant spinning device (3) has been deemed unacceptable, the switchable compressed air valve (12) allocated to at least one spinning unit (4) is moved to the closed position in each case.

6. The method (100) according to any one of claims 1 to 4, characterized in that, The spinning machine (1) is an air-jet spinning machine, wherein the spinning unit (4) is formed by an air-jet spinneret, by means of which a yarn is formed from the fed yarn via the compressed air flow fed to the air-jet spinneret, the compressed air flow generating a vortex air flow within the air-jet spinneret.

7. The method (100) according to claim 3 or 4, characterized in that, The spinning device (3), the spinning unit (4), and / or the compressed air supply line (8) are indicated by means of the display unit (15) in relation to the not permitted deviation.

8. The method (100) according to any one of claims 1 to 4, characterized in that, The degree of deviation from the limit value or the range of limit values ​​is identified and indicated by means of the display unit (15).

9. The method (100) according to any one of claims 1 to 4, characterized in that, The compressed air valve (12) is controllable.

10. The method (100) according to any one of claims 1 to 4, characterized in that, The compressed air valve (12) is designed to control the flow of compressed air supplied.

11. A rotor spinning machine or an air-jet spinning machine (1), comprising: - At least one section, said at least one section comprising a defined number of spinning devices (3), each spinning device having a spinning unit (4). -At least one compressed air source (6), - Compressed air supply lines (8), each of which is coupled to at least one of the spinning units (4), wherein the compressed air flow from the at least one compressed air source (6) can be fed via the compressed air supply lines (8) to the at least one spinning unit (4) allocated to the compressed air supply lines. - A switchable compressed air valve (12), said compressed air valve being assigned to at least one spinning unit (4), wherein said compressed air valve (12) is designed to maintain at least a constant pressure regardless of the pressure volume flow, and - At least one compressed air flow meter (10), said at least one compressed air flow meter being used to measure the compressed air flow rate within the compressed air supply line (8), Its features are, The spinning machine (1) for performing the method (100) according to any one of claims 1 to 10 includes or is coupled to, - A control and regulation unit (14), coupled to the at least one compressed air source (6) and the compressed air valve (12), for controlling and / or regulating the at least one compressed air source (6) and the corresponding compressed air valve (12), and - Evaluation device (13), which is connected to the compressed air flow meter (10) via data transmission for evaluating measurement data from the compressed air flow meter (10). The evaluation device (13) is configured as follows: - As the compressed air valves (12) close one after another in a defined sequence, the dominant compressed air flow value measured each time a compressed air valve (12) closes is compared with a specified limit value or limit range stored in or connected to the evaluation device (13), and - Identify the spinning unit (4) whose assigned compressed air flow value deviates from the limit value or limit range, wherein the assigned compressed air flow value is assessed as being below or above the limit value or limit range.

12. The rotor spinning machine or air-jet spinning machine (1) according to claim 11, characterized in that, The compressed air valve (12) is arranged in the compressed air flow branch pipe (9), and the assigned spinning unit (4) is connected to the compressed air supply line (8) via the compressed air flow branch pipe in order to guide the compressed air flow.

13. The rotor spinning machine or air-jet spinning machine (1) according to claim 11 or 12, characterized in that, The control and regulation unit (14) is connected to the evaluation device (13) via data transmission.

14. The rotor spinning machine or air-jet spinning machine (1) according to claim 11 or 12, characterized in that, The evaluation device (13) is connected to the display unit (15) wirelessly or wiredly via data transmission and is designed such that the display unit (15) indicates the spinning device (3), the spinning unit (4), and the compressed air supply line (8) in relation to the degree of deviation from and / or the limit value or limit range.

15. The rotor spinning machine or air-jet spinning machine (1) according to claim 11 or 12, characterized in that, The compressed air valve (12) is controllable.

16. The rotor spinning machine or air-jet spinning machine (1) according to claim 11 or 12, characterized in that, The compressed air valve (12) is designed to control the flow of compressed air supplied.

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