Method for controlling and / or monitoring the operation of a pump system

Abstract

A method for controlling and / or monitoring the operation of a pump system (1), preferably computer-implemented, in which the pump system (1) comprises a pump (2) and a motor (3) connected to drive the pump (2), comprising the steps of: determining a plurality of cavitation indicators (10), in which each cavitation indicator (11, 12) indicates cavitation or a likelihood of cavitation of the pump (2) for a different operating range (21, 22, 31, 32), wherein each operating range (21, 22, 31, 32) is given by a combination of values of the first motor characteristic and the second motor characteristic.

Description

Field of the technology

[0001] The present disclosure relates to the field of pump systems and to the control and / or monitoring of pump systems. Background art

[0002] When operating a pump, an undesirable phenomenon called cavitation occurs when the suction pressure is too low, which causes boiling bubbles to appear in the pumped medium. At least unplanned work actions need to be carried out to maintain the pump system, such as replacing the impeller and / or the housing of the pump.

[0003] As known from European Patent Application No. EP 21200024.4, the stray flux of the motor is measured and input into a simulation model of the motor. The simulation model determines the operating parameters of the motor and analyzes these operating parameters to identify faults in the motor.

[0004] As known from European Patent Application EP 2 196 678 A1, a method and a system for a pump controlled by an inverter are provided. Among them, one or more characteristics indicating the cavitation or the possibility of cavitation of the pump are determined, so as to detect the cavitation or the possibility of cavitation of the pump by one or more formed characteristics.

[0005] As known from US Patent Application US2016 / 010639 A1, a sensorless technology for pump differential pressure and flow monitoring is provided.

[0006] As known from European Patent Application EP 1 198 871 A1, a method for fault detection of a machine driven by a motor at variable speed is provided. When a fault occurs, the motor is shut down. For this purpose, the machine and / or the unit driven by the machine go through all possible operating states, and the operating values of the motor recorded during the learning function related to the machine and / or the unit driven by the machine are stored, presented and used for fault monitoring. Summary of the invention

[0007] Cavitation can cause erosion of the impeller and / or the housing, and thus damage the pump. It is necessary to avoid running the pump in a cavitation state for a long time at all costs.

[0008] Therefore, it is desirable to prevent interruptions in the equipment (thereby avoiding costly downtime) and ensure the best motor load. At the same time, it is also desirable to prevent faults from occurring in the system and identify impending faults before they occur.

[0009] Therefore, an object of the present invention is to be able to more accurately evaluate the operating state, possible changes, and the distance between the operating point and the undesirable operation where cavitation occurs.

[0010] This object is achieved by the subject matter of the independent claims. The dependent claims provide advantageous embodiments. Description of the Drawings

[0011] Figure 1 Shows a pump system.

[0012] Figure 2 Shows another pump system.

[0013] Figure 3 Shows the visualization of cavitation indices for different operating ranges.

[0014] Figure 4 Shows a pump system and exemplary method steps.

[0015] Figure 5 Shows the visualization of the curves of the first operating point and the second operating point, and the transient operating points between the first operating point and the second operating point.

[0016] Figure 6 Shows the visualization of the change of cavitation index during the operation of the pump system.

[0017] Figures 7 to 15 Shows exemplary method steps. Detailed Description of the Invention

[0018] Figure 1 A pump system is shown. The pump can be used to transport a liquid fluid within a production plant in the processing industry. The pump 2 can be combined with an electric motor 3 driven by three-phase alternating current (AC) from an inverter 6. An actuator and / or a sensor 4 in the pump system can be used together with the pump to generate and monitor a defined (controlled) flow rate of the liquid. A control unit 5 can be used for the automation of the pump system. For this purpose, the control unit can include control functions. For example, in the case of a centrifugal pump, PI flow control is performed by a continuously adjustable proportional valve downstream. The pump itself is controlled by the control unit (direct starter), such as SIMOCODE provided by SIEMENS. A control device 7 with a display screen (such as an industrial PC) can be connected to the control unit 5. The motor characteristics, valve status values, and / or measurement values from one or more sensors in the pump system (for example, in the form of data) can be obtained by the operating device 7. Then, the operating device 7 can be used to further process and / or visualize the obtained data.

[0019] As Figure 1 shown, an actuator in the form of a valve can ensure that no liquid flows through the pump when the pump is shut down. This valve can also be used to control the pump load. The pump load refers to the backpressure and / or resistance to fluid flow that the pump must overcome to make the fluid flow through the pipeline and drill pipe. In addition, to control the pump system, the flow rate, the inlet and outlet side pressures, and / or the temperature of the liquid medium can be measured. A binary liquid detector is used to determine whether there is liquid present.

[0020] One or more sensors can be used to measure multiple characteristics of the pump system. Thus, multiple sensor signals can be measured. For example, the electric active power of the motor 3, the flow rate of the pumped medium, the inlet pressure (suction pressure) of the pump 2, the discharge pressure (delivery pressure) of the pump, and / or a binary signal indicating whether the motor is running can be determined. In addition, for cavitation monitoring, it may be necessary to determine the temperature of the pumped medium. Furthermore, in the case of speed control, the speed of the pump can be determined. In the case where the frequency converter 6 provides the (shaft) power of the motor 3, the mechanical power can be determined. Other characteristics of the motor 3 can include the rated speed, rated power, and rated efficiency. The characteristics of the pump 2 can include the minimum flow rate, rated flow rate, delivery characteristic (H / Q characteristic), power curve (P / Q curve), and / or efficiency curve. Other characteristics can be determined. For example, in the case where the fluid is not water, the fluid-specific vapor value can be determined.

[0021] Faults during the operation of the pump 2 can pose a serious threat. Depending on the appropriate corresponding and / or emergency situations, different monitoring and / or control functions can be implemented for the pump system. Diagnostic results such as severe blockage, dry running, and / or cavitation can be immediately reported to the equipment operator as an alarm (e.g., alarm sound) because these operating states can quickly damage the pump. Then, the automatic emergency shutdown of the pump and / or the closing of the valve can be initiated. In particular, operating states such as cavitation can damage the pump after a period of time, but usually still require a relatively rapid response. In this case, the diagnostic information can be reported to the equipment operator and / or maintenance engineer.

[0022] For example, in the case where the transported liquid is flammable, an explosive atmosphere can form in the pump with the gas / vapor phase together with oxygen (e.g., from air ingress). If cavitation occurs, the material of the impeller, propeller, or valve flap will indeed be eroded. Therefore, in the case where the machine is at risk of cavitation, particularly hard and high-strength materials must be used. Cavitation usually leads to corrosive attack. The protective layer is removed, and the porous surface provides ideal conditions for corrosion. The main criteria for cavitation are the cavitation number and the required net positive suction head. The dimensionless cavitation number σ is a measure of when fluid cavitation occurs. To avoid cavitation, a larger cavitation number σ should be selected as much as possible. The following measures can reduce the cavitation tendency: avoid low pressure, avoid temperatures close to the boiling point of the fluid, use thin blade profiles, select a smaller impact angle for the blades, avoid sudden deflection of the flow, and trim the leading edge to a rounded corner.

[0023] Another criterion is the NPSH value (Net Positive Suction Head). The NPSH value corresponds to the (pressure) energy of the liquid column at the connection flange in the current operating state. This value is always positive. There are two distinctions for the NPSH value: NPSHA (Available Net Positive Suction Head): This is the actual pressure of the device as the head difference in the operating state. NPSHR (Required Net Positive Suction Head): This is the required pressure to operate the pump as the height difference.

[0024] Figure 2 Another pump system is shown. In this system, the motor 3 drives the pump 2, where the motor is directly powered by a three-phase alternating current (AC) main line. To monitor the operation of the pump system, measurement values from one or more sensors (e.g., sensors effectively coupled to the motor) can be collected. In addition, the characteristics of the motor can be determined. The above values can be read from the motor or a separate sensor (e.g., attached to the motor). For example, a control device 7 (such as an industrial PC) can be communicatively coupled to the motor and / or the separate sensor. The pump and the pump system can have one or more operating ranges. As described herein, the pump or the pump system can thus operate in one or more of these operating ranges. For example, the pump system can include one or more acceleration phases and / or deceleration phases of the pump and / or the motor, e.g., during the ramp-up and / or ramp-down of the motor / pump. Generally, the pump (system) can have an allowable operating range including these operating ranges. The operating range can be given by a combination of values of a first motor characteristic and a second motor characteristic.

[0025] Now turning to Figure 3 , the figure shows a plurality of cavitation indicators. Among them, each cavitation indicator indicates the cavitation or the possibility of cavitation of the pump for different operating ranges, where each operating range is given by a combination of values of a first motor characteristic and a second motor characteristic. Therefore, the operating range can be determined by a plurality of values (e.g., intervals) of the first motor characteristic and a plurality of values (e.g., intervals) of the second motor characteristic. The cavitation indicator can present discrete values. As Figure 3 shown, the cavitation indicator can present 10 values. In addition, when no motor characteristics are available or no cavitation indicator can be determined for other reasons, a value for the cavitation indicator can be reserved for such a situation. For example, the motor characteristics can be the motor speed (e.g., speed value) and the motor load (e.g., load value). Therefore, a speed interval (including the speed value range) and a load interval (including the load value range) can be determined, which together constitute the operating range. Among them, the operating range can be given by relating the speed intervals 21, 22 to the load intervals 31, 32. As Figure 3As shown, this can generate a cavitation index 11 for the pairing of interval 21 and interval 31, and a second cavitation index 12 for the pairing of interval 22 and interval 32. Thus, the allowable operating range can have a cavitation index assigned to each or at least multiple operating ranges. The resolution or width of the operating range can be selected based on the update rate or sampling rate of the available speed value or load value.

[0026] As Figure 3 shown, the cavitation index can be visualized, for example, in the form of a heat map. This visualization result can be presented to the user, for example, on the display screen of the control device 7. The heat map is created from data at different operating points. The heat map does not necessarily have to be completely filled.

[0027] In this way, a more accurate assessment of the operating state, possible changes, and / or the distance of the operating point to poor operation with cavitation can be determined.

[0028] The cavitation index can be determined based on pump vibration and / or magnetic flux. Therefore, this may require detecting pump vibration and / or magnetic flux, for example, in addition to the speed and / or load of the drive motor. The vibration and / or magnetic flux (values) can be obtained, for example, via sensors attached to the pump and / or motor, such as SIMOTICS Connect 400, using vibration and magnetic field sensors. In addition, the temperature of the conveyed medium can be measured or estimated by measuring the fluid temperature or the temperature of the surroundings of the fluid. Then, characteristic values for cavitation activity can be determined from the vibration and / or magnetic flux signals.

[0029] Cavitation refers to the appearance and subsequent sudden disappearance of vapor bubbles in the flow of a liquid. During the operation of a pump, such vapor bubbles can be generated due to (local) excessively high flow velocities: the higher the flow velocity, the lower the pressure in the liquid. If the pressure drops below the vapor pressure of the liquid, vapor bubbles will form. If the pressure rises again along the flow direction, the bubbles will burst: the gas inside the bubbles is suddenly compressed. The implosion of such bubbles generates a so-called "jet impact". Extremely high pressure and temperature peaks occur, which are usually many times higher than the load-bearing limit of the pump blade or pump wall material. The surface of the blade or wall will be permanently damaged and eventually destroyed. In addition, even a small amount of cavitation will reduce the efficiency (head) of the pump. The maximum amount of cavitation can even lead to a complete interruption of production.

[0030] The cavitation index can be determined based on the vibration signal. Optionally, other signals, such as motor current, the stray magnetic field of the motor, and / or the acoustic signal of a microphone, can also be used to determine the cavitation index.

[0031] As Figure 3As shown, the cavitation index can exhibit discrete values on a scale, one end of which indicates high cavitation or high cavitation likelihood, and the other end indicates low cavitation or no cavitation or no cavitation likelihood or low cavitation likelihood. One or more thresholds T1 can be determined for the cavitation index.

[0032] Advantageously, during pump system startup or during a period of time with changing load and speed (e.g., a relatively long period of time), data including speed values, load values, and / or vibration and / or flux values are recorded. Different acceleration trajectories can also be employed to cover (e.g., a relatively large) operating range area. Vibration can be in the range of 0.1 Hz to 20 kHz. Sound can be in the range of 0.1 Hz to 100000 kHz. Additionally, as described herein, the pump or pump system can thus operate within one or more operating ranges. For example, the pump system can include one or more transition phases, such as one or more acceleration phases and / or one or more deceleration phases of the pump and / or the motor (e.g., during the ramp-up and / or ramp-down of the motor / pump). Thus, the transition phase can include one or more operating ranges (given by the values of the first motor characteristic and the second motor characteristic). During such a transition phase, the pump system (especially the pump and / or the motor) can transition from one operating point or range to another operating point or range. Now, for example, one or more measurements can be made during the transition phase to obtain the values of the first motor characteristic and / or the second motor characteristic. Thus, during the transition phase, the values of the first motor characteristic and the second motor characteristic can be obtained. Based on the values of the first motor characteristic and the second motor characteristic, a cavitation index can be determined. That is, for example, for one or more pairs of values of the first motor characteristic and the second motor characteristic, a cavitation index can be determined. One or more cavitation indices determined during one or more transition phases (or based on the values of the first motor characteristic and the second motor characteristic during one or more transition phases) can be used to create and / or add to a database that has entries regarding one or more cavitation indices associated with the corresponding operating ranges. Thus, even if one or more values of the first motor characteristic and / or the second motor characteristic have been determined during the transition phase, these one or more values of the first motor characteristic and / or the second motor characteristic can be used to determine one or more cavitation indices, for example, for one or more operating ranges or operating points, such as those included in or covered by the transition phase. The transition phase can be caused by a change in the operating state of the pump system. For example, based on the valve position, the load can increase; and / or based on a change in the volumetric flow rate, the speed can change. Thus, for example, a transition phase can occur or can be initiated. For example, the valve position can be changed based on a control valve setpoint, and / or the volumetric flow rate can be changed based on a speed setpoint. Also, the control valve setpoint and / or the motor speed setpoint can be changed to avoid any area (i.e., one or more operating ranges where the corresponding cavitation index exceeds a predetermined cavitation threshold), for example, when the pump system (especially the pump and / or the motor) switches from a first operating point or range to a second operating point or range.

[0033] Figure 4A pump system and exemplary method steps are shown. A sensor 40 for detecting the vibration and / or magnetic flux of the motor can be attached to the motor or located in the vicinity of the motor 3. Thus, measurement values can be obtained from the pump system. As described herein, the measurement values can be obtained by a control device, which can further process these measurement values. Thus, based on these measurement values, a cavitation index can be determined for each operating state present during the measurement. For example, it may be necessary to obtain sufficient vibration and / or magnetic flux values within a certain specific operating range in order to determine the cavitation index for that operating range. However, the cavitation index can also be estimated, for example, based on a first motor characteristic and / or a second motor characteristic. Then a database can be created, which has entries regarding the operating range and the cavitation index associated with the corresponding operating range. For this purpose, the database can be stored in the memory of the control device or in the memory of another device. Then the cavitation index can be visualized, for example in the form of a heat map, for example to assist the user, for example for controlling the pump (system). Thus, the user can control the operation of the pump system (e.g., the motor and / or the pump) based on multiple cavitation indices. Thus, the operation of the pump system (e.g., the motor and / or the pump) can be controlled (e.g., automatically controlled) based on multiple cavitation indices. That is, the operation can be controlled so as to avoid the cavitation index in one or more operating ranges of the pump exceeding a predetermined cavitation threshold. For example, the user can control the operation of the pump system based on the visualization of the cavitation index, for example by setting the speed and / or load setpoint. In addition to the cavitation index, the operating range given by the combination of the values of the first motor characteristic and the second motor characteristic can also be visualized, for example as the x-axis and y-axis.

[0034] Figure 5 A visualization diagram showing the first operating point O1 and the second operating point O2 and the curves C1, C2 of the (transient) operating points between the first operating point O1 and the second operating point O2 is shown. As before, the coordinate axes respectively correspond to the speed and load of the motor driving the pump. However, other motor characteristics can also be used. The first operating point O1 preferably corresponds to the current operating point of the pump and can be assigned a first cavitation index, which, for example, indicates low cavitation or current cavitation or the likelihood of cavitation. The first operating point O1 can correspond to a first operating range and / or be located within the first operating range. The second operating point, preferably the operating point to be reached, can also be assigned a second cavitation index. The second operating point O2 can correspond to a second operating range and / or be located within the second operating range. Currently, according to the curve C1, the change of the operating point requires the pump (system) to bear the operating points with cavitation and / or a high likelihood of cavitation. Therefore, a second curve C2 is determined, which avoids those operating points where cavitation occurs or is very likely to occur. The second curve is determined such that it avoids the cavitation index exceeding a threshold (e.g., Figure 3The operating point or corresponding operating range (with a threshold T1 therein). Thus, based on the operating range and the cavitation index assigned to (each) operating range, a transition can be achieved between operating points that can cause cavitation.

[0035] Figure 6 A visualization diagram showing the change in the cavitation index during the operation of the pump system is presented. Similarly, the cavitation index is determined for different operating ranges. During the operation of the pump system, the behavior of the pump (i.e., its operating conditions) can change. Therefore, it may be necessary to update the cavitation index after a period of time (e.g., regularly or when a certain event occurs). As Figure 6 shown, at the first time point t1, for example, directly after the commissioning of the pump system, the cavitation index for multiple operating ranges is determined. After the (e.g., long-term) operation of the pump system, at the second time point t2 in terms of time, the cavitation index for (e.g., at least part of) the operating ranges is re-determined and / or updated. As Figure 6 shown, by comparing the visualizations of the cavitation index, a change in the cavitation behavior of the pump (system) can be identified. Based on this comparison, the control settings of the pump system can be adjusted. In addition, in addition to performing anomaly detection, the operating state of the pump, more precisely the fault state, such as damage to the impeller or diffuser, or deposits in the pipeline, can also be determined. In addition, based on this comparison, changes in the process can also be derived.

[0036] Figures 7 to 15 Exemplary method steps are presented. In step S1, multiple cavitation indices can be determined. For example, the cavitation index can be calculated by a processor of the operating device. The cavitation index can be stored in a database. This database can also be located in the memory of the operating device, i.e., the cavitation index is stored in the memory. In step S2, it is determined whether the cavitation index (among the multiple cavitation indices) exceeds a predetermined cavitation threshold. The cavitation threshold can be set by the user, for example, based on experience, and / or based on the pump application, i.e., the use of the pump system.

[0037] The cavitation index and thus each cavitation index among the multiple cavitation indices determines the cavitation or the likelihood of cavitation of the pump. Since the occurrence of cavitation depends on specific circumstances, it is not possible to determine with absolute certainty whether cavitation will occur. Therefore, the cavitation index can be interpreted as representing the probability of cavitation occurring.

[0038] Each cavitation index among the multiple cavitation indices can be determined for different operating ranges. Each operating range is given by a combination of values of the first motor characteristic and the second motor characteristic. For example, for an interval of values, a representative value can be used, such as the middle value or average value of the interval or range as the basis for determining the cavitation index. Optionally, the cavitation index can be determined for all values of the interval or range, and the average value or middle value of these cavitation indices can be used.

[0039] Each operating range can be given by a combination of values of a first motor characteristic and a second motor characteristic. Thus, an operating range can include a single value or can be an interval including multiple values. For example, an operating range can include a first value of the first motor characteristic and a first value of the second motor characteristic. Additionally, an operating range can include multiple values of the first motor characteristic and multiple values of the second motor characteristic. As previously mentioned, the values of the first motor characteristic and the second motor characteristic can be stored in a memory and be related to each other and / or to a cavitation index. This can roughly map the cavitation situation of the pump system, for example, within the allowable operating range of the pump (system) and / or the motor. Thus, the cavitation of the pump system can be determined in a fine-grained manner (refined). To this end, for each of a plurality of operating ranges (e.g., within the allowable operating range of the pump (system) and / or the motor), the cavitation index can be determined (e.g., estimated). When the pump (system) and / or the motor is operating within this operating range or within one or more adjacent operating ranges (in reality), the cavitation index of this operating range can be updated.

[0040] In step S3, in the case where one or more of the plurality of cavitation indices exceed a cavitation threshold, an alarm can be initiated. The alarm can be displayed, for example, on the display screen of the operating device. The alarm can be a notification or an alarm sound and can include information about one or more of the cavitation indices exceeding the cavitation threshold.

[0041] Go to Figure 8 , which shows further exemplary method steps. In step S0, vibration and / or magnetic flux can be measured. The vibration and / or magnetic flux are generated by the motor. The measurement can be performed in different operating ranges. In step S1, as previously mentioned, the cavitation index for the corresponding operating range can be determined based on the measured vibration and / or magnetic flux.

[0042] Go to Figure 9 , in step S1, a plurality of cavitation indices can be determined. Here, the cavitation index can be a cavitation score, for example, on a cavitation scale. Thus, in step S4, the cavitation score can be determined. The cavitation scale can be a (discrete or continuous) cavitation scale, with the first cavitation possibility (e.g., cavitation exists) indicated at one end of the scale and the second cavitation possibility (e.g., no cavitation) indicated at the other end of the scale.

[0043] Go to Figure 10 , in step S5, the distance to one or more other operating ranges is determined. The distance can be between the operating range of the first operating point and one or more other operating ranges. The first operating point or the first operating range can be related to a non-cavitation index or a low cavitation index (e.g., below the cavitation threshold). On the other hand, the first operating point can be related to a high / medium cavitation index.

[0044] It is possible to determine a distance in terms of a first motor characteristic and / or a second motor characteristic, for example given in units of the first motor characteristic and / or the second motor characteristic respectively. One or more other operating ranges can be associated with a cavitation index exceeding a predetermined cavitation threshold or can have a cavitation index exceeding a predetermined cavitation threshold. Thus, it is possible to determine the risk of the operating point of the pump system drifting towards the cavitation region or the region of cavitation likelihood.

[0045] Thus, in step S6, it is possible to (automatically) adjust the control settings of the motor and / or the pump system based on the distance. The control settings of the motor and / or the pump system can be related to the first motor characteristic and / or the second motor characteristic, preferably in order to achieve an operating point with a low / no cavitation index. The first motor characteristic can correspond to the motor speed, and / or the second motor characteristic can correspond to the motor load (torque).

[0046] Go to Figure 11 , in step S6, it is possible to (automatically) adjust the control settings of the motor and / or the pump system based on the distance, for example as described herein. In step S7, this can include adjusting the motor speed setpoint of the motor and / or adjusting the control valve setpoint of the control valve of the pump system. Thus, the pump system can include a valve for controlling the motor load (torque).

[0047] Go to Figure 12 , a further exemplary method step is shown. In step S8, a plurality of cavitation indices are determined during the acceleration phase and / or the deceleration phase of the pump and / or the motor. For this purpose, corresponding vibration and / or magnetic flux measurements are carried out during these phases respectively. The acceleration phase and / or the deceleration phase can correspond to the ramp-up and / or ramp-down of the motor / pump. In this way, the behavior of the motor and / or the pump in different and / or multiple operating ranges can be obtained.

[0048] In step S9, the cavitation index can be re-determined during the operation of the pump system. For example, for repeated acceleration phases and / or deceleration phases, and / or after a predetermined operating time of the pump system. For example, at a first point in time, the cavitation index can be determined for one or more operating ranges, and at a later point in time (and for the same or different operating ranges), the cavitation index can be re-determined.

[0049] Go to Figure 13 , as described above, in step S9, the cavitation index can be re-determined during the operation of the pump system. In step S10, the updated cavitation index can be compared with the previously determined cavitation index, for example for the same or similar (e.g., overlapping) operating ranges. In step S11, based on the comparison, the operating state of the pump / pump system is determined, such as damage to the pump and / or deposits in the pipes at the pump inlet and / or pump outlet.

[0050] Go toFigure 14 , in step S12, for example, by means of a processor of the operating device (such as the above-mentioned control unit), it is possible to determine whether the cavitation index of one or more (e.g., transient) operating points between the first operating point and the second operating point exceeds the cavitation threshold. The same applies to the (transient) operating range between the first operating range and the second operating range. Among them, one or more (transient) operating points or one or more (transient) operating ranges can be located on the curve given by the first motor characteristic and the second motor characteristic. This curve can connect the first operating point and the second operating point, or the first operating range and the second operating range. Now, if cavitation occurs at the operating point or operating range, that is, the cavitation index of these (transient) operating points or operating ranges exceeds the (set) cavitation threshold, then such a curve (for the operating pump system) can be undesirable because it is adverse to the operating life of the pump system. Therefore, in step S13, if the cavitation index of one or more transient operating points exceeds the cavitation threshold, the curve can be adjusted. In this case, when the operation of the pump system changes from the first operating point to the second operating point, the curve can be adjusted to exclude this (transient) operating point or (transient) operating range. In addition, interpolation can be performed on the cavitation index of one or more operating points or one or more operating ranges between the first operating point and the second operating point, or the first operating range and the second operating range. That is, given the cavitation index of the first operating point and the second operating point, or the cavitation index of the first operating range and the second operating range, it is possible to determine the cavitation index of the operating points or operating ranges between them based on the first motor characteristic and / or the second motor characteristic between the operating points or ranges. Similarly, interpolation and / or extrapolation can be performed on the cavitation index of one or more operating points or one or more operating ranges based on at least the first operating point and the second operating point, or the first operating range and the second operating range. In particular, it is determined whether the interpolated and / or extrapolated cavitation index exceeds the cavitation threshold. In particular, among them, one or more transient operating points or one or more transient operating ranges are located on the curve given by the first motor characteristic and the second motor characteristic value, and this curve connects at least one first operating point and the second operating point, or the first operating range and the first operating range.

[0051] Now turn to Figure 15 , in step S1 as described above, a plurality of cavitation indices are determined. In step S14, the plurality of cavitation indices and their corresponding operating ranges can be visualized (e.g., in the form of a heat map) on a display screen of, for example, an operating device (such as a computer or a handheld device).

[0052] It should be understood that the operating ranges are preferably adjacent to each other and cover (at least in part) the allowable operating range of the pump system and / or the motor. That is, the operating ranges can cover the first motor characteristic and / or the second motor characteristic that exist at the rated speed, the rated power, and / or the rated efficiency. The operating ranges can cover the first motor characteristic and / or the second motor characteristic of the pump under the minimum flow rate, the maximum flow rate, the rated flow rate, the delivery characteristic (H / Q characteristic), the power curve (P / Q curve), and / or the efficiency curve.

[0053] Another embodiment includes a computer program that includes program code that, when executed, performs the method steps of any one of the embodiments described herein. Another embodiment includes a (preferably non-volatile) computer-readable medium that includes the computer program.

Claims

1. A method for controlling and / or monitoring the operation of a pump system (1), preferably the method is computer-implemented, wherein, the pump system (1) includes a pump (2) and a motor (3), the motor (3) is connected to drive the pump (2), and the method includes the following steps: Determine a plurality of cavitation indicators (10), wherein each cavitation indicator (11, 12) indicates the cavitation or cavitation possibility of the pump (2) for different operating ranges (21, 22, 31, 32), and each operating range (21, 22, 31, 32) is given by a combination of values of a first motor characteristic and a second motor characteristic.

2. The method according to the preceding claim, further including: Determine whether the cavitation indicators (11, 12) of one or more operating points (O1) of the motor (3) exceed a predetermined cavitation threshold (T1), and the one or more operating points are given by a combination of values of the first motor characteristic and the second motor characteristic within the operating range (21, 22, 31, 32); Initiate an alarm when the cavitation threshold (T1) is exceeded.

3. The method according to any one of the preceding claims, further including: wherein, each operating range (21, 22, 31, 32) is given by a combination of a first range of values of the first motor characteristic and a second range of values of the second motor characteristic.

4. The method according to any one of the preceding claims, further including: Measure the vibration generated by the motor (3) and / or the magnetic flux generated by the motor (3) in different operating ranges, and Determine the cavitation indicators (21, 22, 31, 32) for the operating range based on the measured vibration and / or magnetic flux.

5. The method according to any one of the preceding claims, further including: wherein, The step of determining the cavitation indicators (21, 22, 31, 32) in the different operating ranges includes: Determine a cavitation score on a (discrete or continuous) cavitation scale, which indicates a first cavitation possibility, such as the presence of cavitation, at one end, and a second cavitation possibility, such as the absence of cavitation, at the other end.

6. The method according to any one of the preceding claims, further including: For example, with respect to the first motor characteristic and / or the second motor characteristic, determine the distance from a first operating point in a first operating range, such as the first operating point associated with a zero / low cavitation indicator, to one or more other operating ranges in which the cavitation indicator exceeds the predetermined cavitation threshold.

7. The method according to any one of the preceding claims, further including: For example, with respect to the first motor characteristic and / or the second motor characteristic, determine the distance from a first operating point in a first operating range, such as the first operating point associated with a high / medium cavitation indicator, to one or more other operating ranges in which the cavitation indicator does not exceed the predetermined cavitation threshold.

8. The method according to any one of the preceding claims, further including: Adjust the control settings of the motor and / or the pump system related to the first motor characteristic and / or the second motor characteristic based on the distance, preferably in order to achieve an operating point with a low / no cavitation index.

9. The method according to any one of the preceding claims, further comprises: wherein, the first motor characteristic corresponds to the motor speed and / or the second motor characteristic corresponds to the motor load (torque).

10. The method according to any one of the preceding claims, further comprises: Adjust the motor speed setpoint of the motor and / or adjust the control valve setpoint of the control valve of the pump system, wherein the control valve controls the motor load (torque).

11. The method according to any one of the preceding claims, further comprises: wherein, the plurality of cavitation indices are determined during the acceleration phase and / or the deceleration phase of the pump and / or the motor, for example during the ramp-up and / or ramp-down of the motor / pump.

12. The method according to any one of the preceding claims, further comprises: Redetermine the cavitation index during the operation of the pump system, i.e., update the cavitation index.

13. The method according to any one of the preceding claims, further comprises: Compare the updated cavitation index with the previously determined cavitation index, and Based on the comparison, determine the operating state of the pump / pump system, such as damage to the pump and / or deposits in the pipes at the pump inlet and / or pump outlet.

14. The method according to any one of the preceding claims, further comprises: Interpolate and / or extrapolate the cavitation indices of one or more operating points given by at least a first operating point and a second operating point, or one or more operating ranges given by at least a first operating range and a second operating range, and preferably determine whether the interpolated and / or extrapolated cavitation indices exceed the cavitation threshold, in particular wherein, one or more transient operating points, or one or more transient operating ranges are located on a curve given by the values of the first motor characteristic and the second motor characteristic, the curve connecting at least one of the first operating point and the second operating point, or at least one of the first operating range and the second operating range.

15. The method according to any one of the preceding claims, further comprises: Determine whether the cavitation indices of one or more transient operating points between the first operating point and the second operating point, or the cavitation indices of one or more transient operating ranges between the first operating range and the second operating range exceed the cavitation threshold, wherein the one or more transient operating points are located on a curve given by the first motor characteristic and the second motor characteristic, the curve connecting the first operating point and the second operating point, or the first operating range and the second operating range.

16. The method according to any one of the preceding claims, further comprises: Adjust the curve in the case where the cavitation index at one or more transient operating points, or one or more transient operating ranges, exceeds the cavitation threshold, the curve being given, for example, by a first motor characteristic and a second motor characteristic, and preferably the curve connecting a first operating point and a second operating point, or a first operating range and a second operating range.

17. The method according to the preceding claim, Visualize the plurality of cavitation indices and the corresponding operating ranges on a display.

18. A pump system operable to perform the method steps according to any one of the preceding claims.

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