Method of monitoring rotating machine having plurality of subsystems configured for energy transfer

Abstract

The invention relates to a method of monitoring a rotary machine configured for energy transfer having a plurality of subsystems, each subsystem comprising a cylinder. In the method, a measurement signal of vibration of the rotating machine is acquired; and sampling the vibration measurement signal into a plurality of vibration sub-signals, each vibration sub-signal corresponding to a complete revolution of the rotating machine. A reference oscillator sub-signal is determined based on an average value of the plurality of oscillator sub-signals. The reference oscillator sub-signal is sampled into a plurality of signal segments, each signal segment being assigned to one sub-system of the rotating machine. Cross-correlation analysis of the plurality of signal segments is performed to identify a potential fault state of the rotating machine. The invention also relates to providing a rotary machine configured for energy transfer having a plurality of subsystems, each subsystem comprising a cylinder, where the rotary machine further comprises a control unit adapted to carry out the method according to the invention.

Description

Technical Field

[0001] The present disclosure relates to a method of monitoring a rotating machine having a plurality of subsystems configured for energy transfer, each subsystem comprising a cylinder. The present disclosure also relates to a rotating machine having a plurality of subsystems configured for energy transfer, each subsystem comprising a cylinder. Background Art

[0002] Rotating machines are among the most critical machines in a wide range of industries such as (petro)chemicals, energy, oil and gas. Compared to other rotating machines, rotating machines with cylinders and / or pistons guided in cylinders require more maintenance in some applications. Therefore, it is very important to have advanced monitoring systems to monitor various important machine parameters. Among other things, the monitoring is based on the detection of oscillations and vibrations.

[0003] In machines and systems with moving masses, the causes of dangerous vibrations can be very diverse: imbalance, misalignment, shaft bending, foundation problems, cavitation, gear failure in gearboxes, buildup on fan blades, eddy current vibrations in gases and liquids, electrical or magnetic interference and many other causes.

[0004] Oscillations are repetitive fluctuations in time of state variables. In the context of mechanics, oscillations are understood as the movement of a substance or body about its stationary point. In the case of periodic (i.e. repetitive) oscillations accompanied by deformations of the body, we speak of vibrations. Here, the two terms are used synonymously. Vibrations are described in terms of three mechanical quantities: acceleration, velocity and displacement. These three quantities can be converted into one another by differentiation and integration. In practice, the conversion of the quantities is problematic and sometimes impossible, since measurement errors such as noise can lead to severe distortions of the results after the conversion. It is characteristic for vibrations that all three quantities vary (quasi)periodically, i.e. continuously repetitive signal processes are identifiable. In machines, vibrations are mainly caused directly or indirectly by rotating components. When observing machine vibrations, it can be noticed that the clear sinusoidal signal that is expected to be generated due to the overall rotational motion is not always identifiable. Instead, several vibrations from different sources overlap. For example, in addition to the motor shaft, the gears of a connected gearbox that rotate at a different speed than the shaft can cause vibrations of different frequencies. The superposition of different vibrations makes it difficult to initially evaluate the vibration signal, since it is not possible to recognize at first glance how the measurement signal is composed.

[0005] Vibration measurement is difficult due to the natural mechanical motion of these machines. However, monitoring vibration at various points on the machine is critical to gaining insight into the machine and maintaining a stable process. Vibration values ​​are collected using non-contact displacement sensors, piezoelectric accelerometers, linearized (usually electrodynamic) vibration rate sensors, and air gap sensors.

[0006] US 8,082,125 B2 describes an apparatus and method for condition-based maintenance of a hydrostatic displacement unit. An acceleration sensor is mounted on the hydrostatic displacement unit, records vibration data, and is connected to an evaluation unit that temporarily stores the vibration data. A communication unit connected to the evaluation unit further transmits the data.

[0007] Various condition monitoring concepts are based on a complex analysis and evaluation of the recorded vibrations. Downstream analysis allows for a more in-depth diagnosis of the cause of the vibrations. FFT diagrams, cascade diagrams, waterfall diagrams, orbital diagrams, polar diagrams, Bode or Nyquist diagrams and centroid diagrams are typical forms of analysis in the time or frequency domain.

[0008] It is therefore an object of the present disclosure to overcome or reduce at least some of the disadvantages of the prior art and to provide a method of monitoring a rotating machine configured for energy transfer, the rotating machine having a plurality of subsystems, each subsystem including a cylinder.

[0009] The given object is achieved by the subject matter of the independent claims. Advantageous embodiments of the invention can also be derived from the dependent claims. Summary of the invention

[0010] The invention is defined by the appended claims.

[0011] According to one aspect of the present invention, a method for monitoring a rotating machine is provided, wherein the rotating machine is configured for energy transmission and has a plurality of subsystems, wherein each subsystem includes a cylinder. In the method, a measurement signal of the vibration of the rotating machine is first acquired. The vibration measurement signal is then sampled into a plurality of vibration sub-signals, wherein each vibration sub-signal corresponds to a full revolution of the rotating machine. In addition, a reference vibration sub-signal is determined based on the average value of the plurality of vibration sub-signals. The reference vibration sub-signal is then sampled into a plurality of signal segments, wherein each signal segment is assigned to a subsystem of the rotating machine. In other words, each signal segment corresponds to 1 / n of a full revolution of the rotating machine, wherein n is equal to the number of subsystems. Then, a cross-correlation analysis of the plurality of signal segments is performed to identify potential fault states of the rotating machine.

[0012] The method according to the invention enables monitoring of rotating machines, by data processing of the available vibration data, operating parameters and environmental parameters can be normalized and do not influence the determined results. Furthermore, the method is independent of the positioning of the potentially used sensors for the acquisition of the measurement data.

[0013] The rotary machine preferably comprises an axial piston pump (positive displacement pump) or an isobaric pressure exchanger.The machine typically operates in an operating range of speeds from 500 rpm to 2000 rpm, ie 10 to 20 revolutions per second.

[0014] The measurement signal of the vibration of the rotating machine is preferably obtained by real-time measurement on the rotating machine and / or by reading data from a memory. The latter has the advantage that the method can be executed on a back-end server remote from the actual rotating machine. The vibration is preferably measured optically (laser vibrometer) or by means of an accelerometer. Which type of acceleration sensor (piezoresistive, capacitive, piezoelectric) is used must be adapted to the application and the associated frequency to be measured. The vibration sensor used to capture the real-time measurement is preferably a piezoelectric sensor that captures the vibration. It preferably measures acceleration, velocity or regular vibrations. In addition, the method is advantageously independent of the positioning of the vibration sensor, which can be mounted, for example, to the machine base.

[0015] The acquired vibration measurement signal preferably comprises measurement values ​​over a predetermined (first) time period, preferably a time period of multiple seconds (e.g. 2 seconds). This provides measurement data covering a sufficient number of complete revolutions of the rotating machine and its subsystems, thereby allowing reliable deductions in subsequent method steps. Preferably, the vibration measurement signal is acquired repeatedly, preferably after each end of a predetermined (second) time period, which is preferably a time period of multiple minutes, for example, the vibration measurement signal is acquired every 30 minutes. In this way, the rotating machine is reliably monitored at sufficient intervals.

[0016] The acquired vibration measurement signal is cut into a plurality of vibration sub-signals, wherein each sub-signal refers to a complete revolution of the rotating machine. In other words, the data is parallelized into "same" sub-signals, wherein "same" refers to their time length, rather than the process of measuring signals of different sub-signals. The vibration sub-signals correspond to a complete revolution of all subsystems in the rotating machine. Preferably, the vibration measurement signal includes a duration that results in 10 to 100 such vibration sub-signals. Depending on the rotational frequency, this preferably determines the (first) time period as mentioned above. This provides many vibration sub-signals, which, on the one hand, enables precise and meaningful statements to be made in the further course of the method, and, on the other hand, keeps the computational workload within limits.

[0017] These sub-signals are averaged to eliminate random noise, such as pressure pulsations (which occur at low frequencies) and pulsations due to machine operations (valves, switching operations, etc., which occur at high frequencies). After this step, an averaged baseline vibration sub-signal is obtained for each revolution, which can be considered a "machine fingerprint".

[0018] Then, the reference vibration sub-signal (i.e., "machine fingerprint") is again sampled (cut) into signal segments, where each of these signal segments is associated with a subsystem. Each subsystem includes a cylinder, and each subsystem may also include other components such as gaskets, O-rings, etc. Therefore, each signal segment can be regarded as a "fingerprint" of a subsystem of the rotating machine.

[0019] The plurality of signal segments are then cross-correlated, i.e. the signal segments are compared with each other. Preferably, a known cross-correlation algorithm is used for this cross-correlation. The inventors have found that in new rotating machines, these signal segments are usually highly correlated, i.e. they hardly deviate from each other or only within an acceptable tolerance. The inventors have also found that when the correlation fails, it indicates that one of the subsystems has a problem, which allows using this cross-correlation analysis of the signal segments to determine potential fault states of the rotating machine.

[0020] The method according to the invention thus enables calibration-free and environment-independent monitoring of rotating machines and their subsystems. This allows machine faults to be detected reliably and appropriate measures to be taken in a timely manner, especially before actual damage occurs, since its threat can be detected at an early stage. In particular, fault symptoms due to aging and stress in rotating hydraulic energy machines, especially axial piston pumps and rotary pressure exchangers, increasingly appear during operation, and the method helps to monitor the condition of the machine. It is also advantageous that the arrangement of the machine sensors is essentially irrelevant to the invention, the final measurement results represent the behavior of the subsystems covered by the machine, which define and shape the system to be measured, and due to the comparison of the subsystems, the results or statements about potential problems are not influenced by the sensor arrangement.

[0021] In a preferred embodiment of the present disclosure, the cross-correlation analysis includes performing a comparison of a plurality of signal segments with each other. Additionally or alternatively, the cross-correlation analysis includes determining the deviation of a plurality of signal segments with each other. This enables the identification of a potential fault of at least one subsystem based on the comparison result. Preferably, all signal segments are compared with each other. This provides a very accurate picture of the subsystem because all subsystems are included in the analysis. Preferably, the comparison is performed in pairs by signal segments from two different subsystems. Therefore, the number of comparisons and the obtained comparison results are preferably calculated by dividing the binomial coefficient n by k, where n is the total number of subsystems and k is the number of subsystems selected for comparison. Therefore, for two subsystems, there is one comparison with one obtained result, for three subsystems, there are three comparisons with three obtained results, for four subsystems, there are six comparisons with six obtained results, and so on. Different situations may occur. This approach is particularly advantageous for qualitatively evaluating the behavior of subsystems. A comprehensive and different picture of the subsystem is provided because subsystems that do not show expected behavior or behavior different from other subsystems are highlighted.

[0022] The analysis of the deviation is preferably based on different signal processing methods. In addition, the deviation is preferably determined by comparing local and / or global extreme values ​​of the signal segments. On the one hand, the amplitude can be taken into account, and on the other hand, the number of local extreme values ​​can also be taken into account. For example, the amplitudes of the global maximum values ​​of the signal segments can be compared with each other, and the deviation can be determined on this basis. For example, if the maximum value of the signal segment belonging to the subsystem exceeds the other maximum values ​​of the signal segments belonging to other subsystems, for example, by exceeding a predetermined threshold value (for example, exceeding 3 times the standard deviation σ), this is used as an indication of a faulty subsystem. In addition, the number of local extreme values ​​assigned to the subsystem is particularly high, exceeding the number of local extreme values ​​assigned to other subsystems, which is an indication of faulty behavior. In addition, the area integral of the signal segment and / or the differential of the signal segment can also be used to determine the deviation between them. The combination of the aforementioned factors for determining the deviation thus increases the reliability and accuracy of the derivation, which can then be derived from the combined deviation, preferably based on a suitable weighting of the deviation by different factors. Signal analysis also provides a suitable method for determining the deviation. For example, there is a high deviation in the comparison of one subsystem with other subsystems, while the comparison of other subsystems with each other gives similar results, which further deviates the results of that one subsystem with other subsystems. This will indicate an error in one subsystem as it shows different behavior from other subsystems.

[0023] According to a preferred embodiment of the invention, a comparison of the plurality of signal segments with corresponding segments of the plurality of vibrator sub-signals is performed. Thus, a signal segment based on a reference vibrator sub-signal previously obtained by averaging is compared with a corresponding segment of a plurality of vibrator sub-signals that have not been averaged. In other words, the averaged signal segment is compared with an unaveraged segment relating to the same subsystem. This allows a statement to be derived as to whether there are errors that occur sporadically over time, and in particular errors that are not repeated periodically, which would otherwise not be detected as a result. Preferably, this comparison is performed in conjunction with a comparison of the signal segments with one another, so that on the one hand the previously described results are obtained and on the other hand statements about the behavior of the subsystems compared with one another are made possible.

[0024] Preferably, deviations between the plurality of signal segments and corresponding segments of the plurality of oscillator sub-signals are determined. The deviations may be determined based on the factors described previously. This allows statements to be made about whether there are errors that occur sporadically, and in particular errors that do not repeat periodically, which would otherwise not be detected. Preferably, this comparison is performed in conjunction with determining at least one deviation of the signal segments from one another, so that on the one hand the previously described results are obtained and on the other hand statements about the behavior of the subsystems in comparison with one another are made possible.

[0025] According to another preferred embodiment, the cross-correlation analysis comprises: determining a reference signal segment based on an average value of a plurality of signal segments, and performing a comparison of the reference signal segment with at least one signal segment, and / or determining at least one deviation between the reference signal segment and at least one signal segment of the plurality of signal segments. Through such a cross-correlation analysis, the identification of a potential fault of at least one subsystem based on the comparison result can be performed in more detail and more accurately. Preferably, the reference signal segment is compared with each of the plurality of signal segments, which improves the accuracy of identifying a potential fault of at least one subsystem based on the comparison result. The average value (mean) is a number determined from a given number according to a specific calculation rule. Commonly used calculation rules are arithmetic mean, geometric mean and quadratic mean. In this example, the average value is not limited to a specific calculation rule. The median is also an average value in the sense of the present invention, wherein the median describes the value that divides the data set into two halves.

[0026] According to this embodiment, the reference signal segment is an expected value of a plurality of signal segments. Preferably, the attribute of the reference signal segment (preferably the amplitude of the global maximum of the reference signal segment) is also the expected value of the corresponding attribute of the plurality of signal segments. In this case, this further preferred embodiment comprises: determining at least one deviation between the attribute of the reference signal segment and the corresponding attribute of at least one of the plurality of signal segments. Preferably, a potential fault state is identified if the determined deviation exceeds a deviation interval of plus or minus 3 times the standard deviation σ from the expected value. In other words, the corresponding attribute of at least one signal segment is outside the deviation interval of plus or minus 3 times the standard deviation σ from the expected value. For example, if the amplitude of the compared signal segment is within an interval of plus or minus 3 times the standard deviation σ around the expected value (amplitude of the reference signal segment), the condition is not met, which allows us to assume that the subsystem is working.

[0027] Especially in the case of first commissioning or close to first commissioning, where the subsystems are new and have not yet been subjected to any loads and therefore have no weaknesses or errors, it is possible to determine a reference signal segment representing a plurality of subsystems. Small deviations are inevitable, for example due to materials and manufacturing, and do not cause problems or indicate errors. By determining the reference signal segment based on the average value, this can be taken into account and a representative signal can be used for comparison, which can be regarded as an error-free reference subsystem. Because the subsystem is now only compared with the reference signal segment, the workload of the comparison can also be reduced. In the case where one or more subsystems exhibit a significantly different behavior from the other subsystems, this can be detected by comparing the signal segment with the reference signal segment. The deviation can be determined based on what has been described above. Therefore, the signal segment is used to determine the deviation, whereby each signal segment is assigned to a subsystem. They are adjusted for possible interference and noise as well as random deflections so that such mechanisms have a smaller influence on the determined deviation. Then, the impending failure of the subsystem is indicated by an increase in the deviation between the signal segment of the subsystem and the reference signal segment.

[0028] An additional preferred embodiment of the method comprises the step of performing a comparison of a reference signal segment with corresponding segments of a plurality of vibration sub-signals. The reference signal segment is a kind of fingerprint for each subsystem. The reference signal segment is a kind of "ideal value", in particular for initial commissioning or short-term operation, in which case no errors are present or expected in the components of the subsystem at this time. Therefore, the reference signal segment serves as a suitable comparison object. By comparing the corresponding segment with the reference signal segment, it is possible to assess the extent to which the segments of the subsystem correspond to the ideal behavior. The plurality of vibration sub-signals each comprise a signal corresponding to one complete revolution of the rotating machine and comprise segments which in turn refer to the subsystem. Thus, information about the rotating machine and its subsystems can be obtained at a plurality of time intervals. If this information exhibits atypical behavior, this can be identified because the segments do not represent average values.

[0029] Preferably, a deviation between a reference signal segment and a corresponding segment of a plurality of oscillator sub-signals is determined. The deviation can be determined based on what has been described previously. This allows statements to be made about whether there are errors that occur sporadically, and in particular errors that do not repeat periodically, which would otherwise not be detected. More preferably, the comparison is performed in conjunction with determining a deviation between a reference signal segment and at least one signal segment of the plurality of signal segments, so that on the one hand the previously described results are obtained and on the other hand statements about the behavior of the subsystems in comparison with one another are made possible.

[0030] According to another preferred embodiment of the present invention, the method comprises a step of performing a comparison of the at least one deviation with a first threshold value. The deviation may be any deviation described in the previous preferred embodiment. Preferably, the first threshold value is a relative threshold value. In other words, the threshold value is preferably a percentage value representing a percentage deviation defined by the user and considered as permissible. For example, this allows to take into account random deviations that still exist due to divergence around the expected value.

[0031] In a further preferred embodiment of the second preferred embodiment, a potential fault in the rotating machine is determined when at least one deviation exceeds a first threshold value. If the deviation exceeds the first threshold value, there is a high probability that an error actually exists. For example, an imminent fault or problem in a subsystem is marked by a deviation from the mean or median value of the signal segment, wherein the first threshold value preferably serves as a relative threshold value for such a deviation.

[0032] Preferably, when a potential failure of a rotating machine is identified, a warning message is output and / or the rotating machine is stopped. It allows the user to be informed of a potential failure of a subsystem, i.e. if a subsystem is defective, a warning indicating an error will appear. Furthermore, an automatic stop of the machine is performed and a specialist can conduct further investigations and replace the faulty component. This avoids long downtimes that may occur if a failure is not detected in time and that may result in damage to affected components and parts of the system or to the entire system. In addition to increasing the repair costs, this may also result in higher costs due to the extended downtime. The process according to the invention avoids this.

[0033] In another preferred embodiment of the invention, the method further comprises the steps of: performing a comparison of the at least one deviation with a first threshold value and a second threshold value; outputting a warning message if the at least one deviation exceeds the first threshold value; and stopping the machine if the at least one deviation exceeds the first threshold value and the second threshold value. In this way, different situations can be distinguished, where the rotating machine is still functional and tolerable, and where the machine is not stopped if the deviation is still within a range that prompts the operator to conduct further investigations, so that these investigations are carried out at an appropriate time, which can be appropriately integrated into the operating procedures. However, if the deviation is within a range that can be regarded as critical to the condition of the rotating machine, an immediate stop may be required and significant damage will be prevented.

[0034] According to another preferred embodiment of the invention, the rotational frequency of the rotating machine is determined, wherein the sampling of the vibration measurement signal is based on this rotational frequency. The sampling is supported and made more precise by the previously determined rotational frequency. Based on the knowledge about the number of subsystems and the rotational frequency, combined with the also known time length of the vibration measurement signal, an exact division of the complete signal into vibration sub-signals can be performed, which correspond exactly to one complete revolution of the rotating machine.

[0035] Preferably, the rotational frequency is determined based on the detected sensor value and / or the vibration measurement signal. The detected sensor value and / or the vibration measurement signal characterizes the rotational frequency. The rotational frequency of the rotating machine is the main component in the frequency spectrum of the generated mechanical vibrations, so the rotational frequency can be determined based on the vibration measurement signal. Preferably, a light barrier or other switching sensor is used to measure the time it takes for the rotating machine to complete one revolution. Thus, the rotational speed can be determined.

[0036] According to a further preferred embodiment, the method further comprises acquiring at least one other measurement signal of the vibration of the rotating machine and performing the method according to the invention for the at least one other measurement signal.This allows mapping and tracking the dynamic development of the rotating machine.

[0037] A preferred embodiment of the invention further comprises: determining the deviations between the plurality of signal segments obtained based on the measurement signal; determining the deviations between the at least one other plurality of signal segments obtained based on the at least one other measurement signal; and sorting the plurality of signal segments and the at least one other plurality of signal segments based on the respective deviations. In particular, this avoids "averaging" signals, which actually indicate that one subsystem has deviated from the other subsystems. Deviations include deviations from each other, but also deviations between a plurality of signal portions or a plurality of other signal portions and a mean or median and / or a respective corresponding reference signal portion or another reference signal portion. This is achieved by sorting the signal segments, for example according to the deviations of the signal segments from each other, and / or preferably the deviations of the signal segments from the median / average value. For example, one starts with the "worst" signal segment, i.e. the segment with the largest deviation from the other subsignals or medians, and then continues in the correct time sequence. This does not necessarily allow a 1:1 identification of the piston, for example, if the original "worst" subsystem is surpassed by another subsystem that has failed. In the current solution, this subsystem replaces the original worst subsystem as the first subsystem in the sorting order. However, this approach is sufficient to detect failures of a single subsystem. Advantageously, for the threshold value, only the distance between the first order sub-segments and the median value needs to be monitored.

[0038] According to another preferred embodiment, the allocation of the subsystem to the allocated signal segments is determined based on the detected and / or acquired allocation signal. Preferably, the allocation of the subsystem to the allocated segments of multiple vibration sub-signals is determined based on the detected and / or acquired allocation signal. For example, vibrations occur at different phase positions. In many cases, the cause of the vibration can only be analyzed by measuring the phase position. By allocating the subsystems to the allocated signal segments, the method can even provide a status report for the individual subsystems. Therefore, if the subsystem is not obviously damaged, it can be replaced by non-experts or earlier. Therefore, the signal segments are allocated to the individual subsystems.

[0039] Preferably, the assignment is determined based on correlating the detected and / or acquired assignment signal with the vibration measurement signal. This can be achieved, for example, based on additional reference signals, such as the overall machine rotational position of the rotating machine, a laser or reflector indicator signal, etc. For example, the shaft position is additionally recorded by means of a reference sensor (and preferably the rotational frequency is determined simultaneously). Characteristic values ​​evaluating the vibration level (such as the amplitude vRMS of the vibration, the RMS value of the harmonic vibration components, etc.) are then monitored. In this way, subsystems causing atypical vibration subsignals can be determined and replaced.

[0040] In another preferred embodiment of the invention, an autocorrelation analysis of signal segments based on different measurement signals and assigned to the same subsystem of the rotating machine is performed to identify potential fault states of the rotating machine. Thus, in other words, a signal segment is compared with itself at another moment in time. Thus, the temporal development of the subsystems can be monitored. In particular, in the case where all subsystems behave similarly compared to each other and, for example, "deteriorate", i.e. develop errors, this may not be detected. A comparison with each other would not reveal any significant differences, since all subsystems develop equally "badly". However, by comparing the same subsystem with itself at different times (for example, after a few days or weeks), such an overall deterioration can be reliably detected.

[0041] According to another aspect of the invention, there is provided a rotating machine configured for energy transmission, the rotating machine having a plurality of subsystems, each subsystem comprising a cylinder, wherein the rotating machine further comprises a control unit adapted to perform the method according to the invention.

[0042] Unless indicated to the contrary herein, the different embodiments of the disclosure described herein may be advantageously combined.

[0043] Reference is now made to the following drawings to describe in more detail the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0045] Figure 1a A first accelerometer signal of an axial 5-piston pump is illustrated.

[0046] Figure 1b Pictured Figure 1a an amplified portion of the first accelerometer signal.

[0047] Figure 2 A second accelerometer signal of an axial 5-piston pump is illustrated.

[0048] Figure 3 Pictured Figure 2 The sampled vibration measurement signal of the second accelerometer signal.

[0049] Figure 4 Pictured Figure 2 The reference vibration sub-signal of the second accelerometer signal

[0050] Figure 5 Pictured Figure 2 A reference signal segment of the second accelerometer signal.

[0051] Figure 6 A method of monitoring a rotating machine having multiple subsystems configured for energy transfer according to an embodiment of the present invention is illustrated.

[0052] The present invention is defined by the appended claims. The following description is limited thereto. Any disclosure outside the scope of the claims is intended for illustration and comparison purposes only.

[0053] Therefore, processes, elements, and techniques that are not considered necessary for those skilled in the art to fully understand the various aspects and features of the present disclosure may not be described.In the drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity.

[0054] As used herein, the term "and / or" includes any and all combinations of one or more associated listed items. In addition, the use of "may" when describing embodiments of the present disclosure refers to "one or more embodiments of the present disclosure." In the following description of embodiments of the present disclosure, unless the context clearly indicates otherwise, terms in the singular may include plural forms.

[0055] It should be understood that although the terms "first" and "second" are used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be named a second element, and similarly, a second element may be named a first element. When expressions such as "at least one" are in front of a list of elements, they modify the entire list of elements, rather than modifying individual elements in the list.

[0056] As used herein, the terms "substantially," "approximately," and similar terms are used as terms of approximation rather than as terms of degree, and are intended to take into account the inherent deviations in measured or calculated values ​​that those skilled in the art will recognize. In addition, if the term "substantially" is used in conjunction with a feature that can be expressed using a numerical value, the term "substantially" means a range of + / - 5% of a value centered on that value.

[0057] It will also be understood that the terms “comprises,” “includes,” “has,” or “carries” specified attributes, regions, fixed numbers, steps, processes, elements, parts, and combinations thereof, but do not exclude other attributes, regions, fixed numbers, steps, processes, elements, parts, and combinations thereof.

[0058] In the following description of the embodiments of the present invention, terms in the singular form may include plural forms unless the context clearly indicates otherwise.

[0059] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and / or this specification, and should not be interpreted in an idealized or overly formal sense, unless explicitly defined as such herein. DETAILED DESCRIPTION

[0060] Figure 1a The diagram shows a first accelerometer signal of an axial 5-piston pump. This is therefore a first measurement signal 1 of the vibration of a rotating machine. The signal comprises a duration which comprises a number of complete revolutions of the rotating machine. Thus, a corresponding portion of the first measurement signal 1 of vibration is repeated at periodic intervals. The rotating machine is an axial piston pump with 5 subsystems, each comprising a cylinder and a piston, and other components which are not further mentioned but are common. The dashed rectangle represents a portion of the first vibration measurement signal 1 which comprises one revolution of the rotating machine.

[0061] Figure 1b The diagram shows an enlarged portion of the first accelerometer signal of FIG1 marked by a dotted rectangle. The portion comprises five segments 11 to 15 of the first measurement signal 1, each segment being assigned to a subsystem and being due to vibrations of the subsystem. The first vibration measurement signal 1 indicates Figure 1b The deflection marked with an asterisk in is different from the other 4 segments that do not have this deflection, which indicates a fault in the subsystem.

[0062] Figure 2 A second accelerometer signal of an axial 5-piston pump is illustrated. This is a second measurement signal 2 of the vibration of the rotating machine, which is obtained by means of an accelerometer on the rotating machine by real-time measurement and / or by reading data from a memory.

[0063] Figure 3 Pictured Figure 2 The sampled second vibration measurement signal 2 is a second accelerometer signal. Figure 2The second vibration measurement signal 2 shown in is sampled into a plurality of vibration sub-signals 21 to 25, each of which corresponds to a complete revolution of the rotating machine. Other vibration sub-signals can also be acquired, but they are not shown for clarity reasons. Each vibration sub-signal 21 to 25 includes five segments 2x1 to 2x5 demarcated from each other by the dotted lines of the second measurement signal 1, each segment is assigned to a subsystem, and is caused by the vibration of the subsystem (x=1...5). In other words, the first vibration sub-signal 21 includes a first segment 211 of the first vibration sub-signal, a second segment 212 of the first vibration sub-signal, a third segment 213 of the first vibration sub-signal, a fourth segment 214 of the first vibration sub-signal, and a fifth segment 215 of the first vibration sub-signal. The same applies to the second vibration sub-signal, and so on. Therefore, there are now several vibration sub-signals 21 to 25, each vibration sub-signal includes a number of segments 2x1 to 2x5 corresponding to the number of subsystems, and the segments of each vibration sub-signal are arranged in the same order as another vibration sub-signal. Therefore, each of the vibrator sub-signals 21 to 25 includes a signal at a different point in time, but all of the vibrator sub-signals are measured in the same way.

[0064] Figure 4 Picture shows Figure 2 The reference oscillator sub-signal 20 is a reference oscillator sub-signal 20 of the second accelerometer signal of FIG. The reference oscillator sub-signal 20 is determined based on the average value of multiple oscillator sub-signals 21 to 25. Therefore, the reference oscillator sub-signal 20 also includes parts that are each assigned to a subsystem. These parts are the first signal snippet 201 to the fifth signal snippet 205. The reference oscillator sub-signal 20 can be regarded as an "axial pump fingerprint". Therefore, the signal segments 201 to 205 are fingerprints of a related subsystem. The asterisk marks an additional local extremum that occurs only in the signal segment 205, which is the reason why the signal segment 205 is different from the other signal segments, indicating a potential error.

[0065] Figure 5 Picture shows Figure 2 The reference signal segment 30 of the second accelerometer signal. Figure 4The reference vibration sub-signal 20 shown in is sampled into a plurality of signal segments 201 to 205, each of which is assigned to a subsystem of the rotating machine. A reference signal segment 30 is determined based on the average of the plurality of signal segments. In the reference signal segment 30 which is preferred for comparison, the extreme value is only implicitly presented because it has been attenuated by averaging. A cross-correlation analysis of each of the signal segments 201 to 205 representing the average subsystem and the reference signal segment 30 representing the reference subsystem will show that the subsystems assigned to the signal segments 201 to 204 are well correlated, although not perfectly, while the subsystem assigned to the signal segment 205 is much less correlated.

[0066] Figure 6 The method for monitoring a rotating machine having multiple subsystems configured for energy transmission according to an embodiment of the present invention is illustrated. In a first step S100, obtaining Figure 2 A second vibration measurement signal 2 of the rotating machine is shown. The measurement in step S100 is preferably performed every 30 minutes for a duration of 2 seconds.

[0067] In step S200, the rotational frequency of the rotating machine is determined. Preferably, the rotational frequency is determined based on the detected sensor value and / or the second vibration measurement signal 2. The rotational frequency of the rotating machine is the main component in the spectrum of the generated mechanical vibration, so the rotational frequency can be determined based on the second vibration measurement signal 2. Preferably, a light barrier or other switching sensor is used to measure the time it takes for the rotating machine to complete one revolution. Therefore, the rotational speed can be determined.

[0068] In step S300, the second vibration measurement signal 2 is sampled into a plurality of vibration sub-signals 21 to 25. The sampling of the second vibration measurement signal 2 is based on the rotation frequency. The sampling is supported and made more precise by the previously determined rotation frequency. Based on the knowledge about the number of subsystems and the rotation frequency, combined with the also known time length of the second vibration measurement signal 2, an accurate division of the complete signal into vibration sub-signals 21 to 25 can be performed, which corresponds exactly to one complete revolution of the rotating machine.

[0069] In step S400, a reference vibrator signal 20 is determined. The vibrator signals 21 to 25 are averaged to eliminate random noise, such as pressure pulsations and pulsations due to machine operation. After this step S400, an average reference vibrator signal 20 is obtained for each revolution, which can be considered a "pump fingerprint".

[0070] Subsequently, in step S500, the reference oscillator signal 20 is sampled into a plurality of signal segments 201 to 205. The reference oscillator signal 20 (pump fingerprint) is cut (not shown) into signal segments 201 to 205, wherein each of these signal segments 201 to 205 is associated with a subsystem having a cylinder and a piston, wherein each subsystem may also include a gasket, an O-ring, etc. Therefore, each signal segment 201 to 205 is a fingerprint of a related subsystem.

[0071] In step S600, a reference signal segment 30 is determined. Thus, a reference signal segment 30 representative of a plurality of subsystems is determined. If the method according to the invention is performed for the first time after commissioning, a reference signal segment 30 is provided which can be regarded as error-free behavior and thus facilitates further comparisons.

[0072] In step S700, a cross-correlation analysis of the plurality of signal segments 201 to 205 is performed. The cross-correlation analysis comprises determining at least one deviation between a reference signal segment 30 and at least one signal segment of the plurality of signal segments 201 to 205, which is performed in step S710. Furthermore, in step S720, the plurality of signal segments 201 to 205 are sorted based on the respective deviations previously determined.

[0073] Subsequently, in step S730, a comparison of the at least one deviation with a first threshold and a second threshold is performed. The first threshold and the second threshold are preferably relative thresholds. When the at least one deviation exceeds the first threshold, it is determined that the rotating machine has a potential fault. In step S800, if the at least one deviation exceeds the first threshold, a warning message is output, and if the at least one deviation exceeds the first threshold and the second threshold, the machine is additionally stopped in step S900.

[0074] According to an additional preferred embodiment, the method further comprises: acquiring at least one further measurement signal of the vibration of the rotating machine and performing the method according to the invention for the at least one further measurement signal. This occurs in step S100', in which further measurement signals of the vibration of the rotating machine are acquired.

[0075] Therefore, in step S200 ′, another rotation frequency of the rotating machine is determined, and then in step S300 ′, another vibration measurement signal is sampled into another plurality of vibration sub-signals based on the other rotation frequency.

[0076] After this, another reference oscillator signal is determined in step S400 ′.

[0077] In step S500 ′, the other reference oscillator signal is sampled into another plurality of signal segments.

[0078] In addition, in step S600 ′, another reference signal segment is acquired.

[0079] In step S700', a cross-correlation analysis of the plurality of other signal segments is then subsequently performed. This includes determining a deviation between the other reference signal segment and at least one other signal segment of the plurality of other signal segments in step S710'. Subsequently, the plurality of other signal segments are sorted in step S720'.

[0080] In step S750, an auto-correlation analysis of signal segments based on different measurement signals and assigned to the same subsystem of the rotating machine is performed to identify potential fault states of the rotating machine. In other words, signal segments 201 to 205 based on the second vibration measurement signal 2 are compared with other signal segments based on other vibration measurement signals. In each case, the signal segment is compared with other signal segments assigned to the same subsystem. However, the main difference is that the signal segment and the other signal segments provide information about the corresponding subsystem at different times. For example, one vibration measurement signal can be compared with another vibration measurement signal received after the above-mentioned 30-minute interval. The comparison can also cover a larger interval, for example, the comparison of a signal segment of a vibration measurement signal with a signal segment of another vibration measurement signal received a week later is preferred. In this way, the development over time can be advantageously monitored. In addition, subsequent measurements and autocorrelations can be repeated multiple times to obtain timing information of vibration data of each subsystem respectively.

[0081] In step S800', a warning message is outputted and / or in step S900' the machine is stopped. This is dependent on the detected deviations between at least one other plurality of signal segments, wherein there may be deviations from one another and / or from another reference signal segment. Preferably, the deviations leading to the warning and / or the stop also include deviations determined during the autocorrelation analysis.

[0082] Reference numerals

[0083] 1 First vibration measurement signal / first vibration measurement signal

[0084] 11 Segment of the first subsystem of the measurement signal

[0085] 12 Segment of the second subsystem measuring the signal

[0086] 13 Segment of the third subsystem measuring the signal

[0087] 14 Segment of the fourth subsystem of the measurement signal

[0088] 15 Segment of the fifth subsystem measuring the signal

[0089] 2 Second vibration measurement signal / second vibration measurement signal

[0090] 20 Reference oscillator signal

[0091] 201 First signal segment

[0092] 202 Second signal segment

[0093] 203 Third signal segment

[0094] 204 Fourth signal segment

[0095] 205 Fifth Signal Fragment

[0096] 21 First oscillator signal

[0097] 211 The first segment of the first oscillator signal

[0098] 212 The second segment of the first oscillator signal

[0099] 213 The third segment of the first oscillator signal

[0100] 214 The fourth segment of the first oscillator signal

[0101] 215 The fifth segment of the first oscillator signal

[0102] 22 Second oscillator signal

[0103] 23 Third oscillator signal

[0104] 24 Fourth oscillator signal

[0105] 25 Fifth oscillator signal

[0106] 251 The first segment of the fifth oscillator signal

[0107] 252 The second segment of the fifth oscillator signal

[0108] 253 The third segment of the fifth oscillator signal

[0109] 254 The fourth segment of the fifth oscillator signal

[0110] 255 The fifth segment of the fifth oscillator signal

[0111] 30 Reference signal segments

[0112] S100 acquires vibration measurement signals from rotating machines

[0113] S200 Determines the rotational frequency of rotating machines

[0114] S300 samples the vibration measurement signal into multiple vibration sub-signals

[0115] S400 Determine the reference oscillator signal

[0116] S500 samples the reference oscillator signal into multiple signal segments

[0117] S600 Determine reference signal segment

[0118] S700 performs cross-correlation analysis of multiple signal segments

[0119] S710 Determine at least one deviation between a reference signal segment and at least one signal segment of a plurality of signal segments

[0120] S720 Sort multiple signal fragments

[0121] S730: Compare at least one deviation with a first threshold and a second threshold

[0122] S800 outputs warning message

[0123] S900 Stop the machine

[0124] S100' Acquisition of another measurement signal of the vibration of a rotating machine

[0125] S200' Determine a different rotational frequency of a rotating machine

[0126] S300' samples other vibration measurement signals into other multiple vibration sub-signals

[0127] S400' Determine another reference oscillator signal

[0128] S500' Sampling other reference oscillator signals into other multiple signal segments

[0129] S600' Determine another reference signal segment

[0130] S700' Perform cross-correlation analysis on multiple other signal segments

[0131] S710′ Determine a deviation between another reference signal segment and at least one signal segment of a plurality of other signal segments

[0132] S720' Sort multiple other signal fragments

[0133] S750 performs autocorrelation analysis on signal segments

[0134] S800' Output warning message

[0135] S900' Stop the machine

Claims

1. A method for monitoring a rotating machine, the rotating machine being configured for energy transmission and having a plurality of subsystems, each subsystem comprising a cylinder, the method comprising the following steps: Acquiring a measurement signal of vibration of the rotating machine (2); Sampling the vibration measurement signal (2) into a plurality of vibration sub-signals (21, 22, 23, 24, 25), each vibration sub-signal (21, 22, 23, 24, 25) corresponding to a complete revolution of the rotating machine; Determining a reference vibrator signal (20) based on an average value of the plurality of vibrator signals (21, 22, 23, 24, 25); Sampling the reference vibration sub-signal (20) into a plurality of signal segments (201, 202, 203, 204, 205), each signal segment (201, 202, 203, 204, 205) being assigned to a subsystem of the rotating machine; and A cross-correlation analysis of the plurality of signal segments (201, 202, 203, 204, 205) is performed to identify a potential fault condition of the rotating machine.

2. The method according to claim 1, wherein: The cross-correlation analysis includes: performing a comparison of the plurality of signal segments (201, 202, 203, 204, 205) with one another; and / or Deviations of the plurality of signal segments (201, 202, 203, 204, 205) from one another are determined.

3. A method according to any one of the preceding claims, wherein: The cross-correlation analysis includes: determining a reference signal segment (30) based on an average value of the plurality of signal segments (201, 202, 203, 204, 205); and performing a comparison of the reference signal segment (30) with at least one signal segment (201, 202, 203, 204, 205); and / or At least one deviation between the reference signal segment (30) and at least one signal segment of the plurality of signal segments (201, 202, 203, 204, 205) is determined.

4. The method according to claim 2 or 3, wherein: The method further comprises: A comparison of the at least one deviation with a first threshold value is performed.

5. The method according to claim 4, wherein: The method further comprises: When the at least one deviation exceeds the first threshold, it is determined that the rotating machine has a potential fault.

6. A method according to any one of the preceding claims, wherein: The method further comprises: When a potential failure of the rotating machine is identified, a warning message is output and / or the rotating machine is stopped.

7. The method according to claim 4, wherein: The method further comprises: performing a comparison of the at least one deviation with the first threshold and a second threshold; If at least one deviation exceeds said first threshold, outputting a warning message; and If at least one deviation exceeds the first threshold and the second threshold, the machine is stopped.

8. A method according to any one of the preceding claims, wherein: The method further comprises: determining a rotational frequency of the rotating machine, Therein, the sampling of the vibration measurement signal is based on the rotation frequency.

9. The method according to claim 8, wherein: The rotation frequency is determined based on the detected sensor value and / or the vibration measurement signal (2).

10. The method according to claim 1, wherein: The method further comprises: At least one further measurement signal of the vibrations of the rotating machine is acquired and the method according to claim 1 is performed on the at least one further measurement signal.

11. The method according to claim 10, wherein: The method further comprises: determining a deviation between the plurality of signal segments (201, 202, 203, 204, 205) obtained based on the measurement signal; determining a deviation between the at least one other plurality of signal segments obtained based on the at least one other measurement signal; and The plurality of signal segments (201, 202, 203, 204, 205) and the at least one other plurality of signal segments are sorted based on the respective deviations.

12. A method according to any one of the preceding claims, wherein: The method further comprises: Based on the detected and / or acquired allocation signals, an allocation of the subsystems to the allocated signal segments (201, 202, 203, 204, 205) is determined.

13. The method according to claim 12, wherein: The assignment is determined based on correlating the detected and / or acquired assignment signal with the vibration measurement signal (2).

14. The method according to claim 10 or 11, further comprising the following steps: An autocorrelation analysis of signal segments (201, 202, 203, 204, 205) based on different measurement signals and assigned to a same subsystem of the rotating machine is performed, configured to identify a potential fault state of the rotating machine.

15. A rotating machine having a plurality of subsystems configured for energy transmission, each subsystem comprising a cylinder, the rotating machine comprising a control unit adapted to perform the method according to any of the preceding claims.

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