PUMP FOR TRANSFERRING A MEDIUM AND METHOD FOR MONITORING

Description

[0001] The invention relates to a pump for conveying a (fluid) medium, in particular a liquid or a solid-liquid mixture or a liquid-gas mixture, with at least one drive, a first shaft and a second shaft driven in rotation by the first shaft, which is connected to a pump element or is part of a pump element, wherein the first shaft is connected to the second shaft by means of at least one connection (or coupling), wherein during operation the first shaft rotates at a first angle of rotation and the second shaft rotates at a second angle of rotation, each relative to a common zero angle.

[0002] The pump is preferably a positive displacement pump, in particular an eccentric screw pump, which has at least one stator (e.g. made of an elastic material) and a rotor rotating in the stator as the pump element. In such an eccentric screw pump, the rotor can be connected to the drive, for example, via at least one coupling rod, which is also referred to as a cardan shaft. This means that a drive shaft or a connecting shaft connected to the drive, which forms the first shaft, is connected to the rotor in an articulated manner via the coupling rod or a comparable element, so that the second shaft is part of this rotor, e.g. as the rotor head. The coupling rod is therefore connected to the first shaft (second connecting shaft / drive shaft) by a first (drive-side) joint and to the second shaft, e.g. to the rotor head of the rotor, by a second (rotor-side) joint.The coupling rod enables the eccentric movement of the rotor or rotor head of such an eccentric screw pump. The pump has a pump housing, e.g., the suction housing, which is connected to the stator on the suction side, for example, and which usually has a housing opening, e.g., an inlet opening, for the medium to be pumped. The pump also has a pump housing, e.g., the pressure side, which is connected to the stator, e.g., a pressure port and / or a pressure-side line. Such an eccentric screw pump is a pump from the group of rotating positive displacement pumps, which are used to pump a wide variety of media, particularly highly viscous liquids, in various industrial sectors. The media to be pumped can, for example, also contain solids. As an alternative to an eccentric screw pump, the pump can be another type of positive displacement pump with a rotating shaft or shafts.

[0003] Eccentric screw pumps of the type described are known, for example, from DE 102014 112 552 A1, DE 10 2010 037 440 A1, WO 2009 / 024279 A1 or DE 10 2018 113 347 A1.

[0004] Fundamentally, there is a need to monitor the condition and / or operation of pumps, e.g., progressive cavity pumps. The primary focus was on monitoring wear on the stator, which is subject to wear due to its elastic material.

[0005] DE 20 2005 008 989 U1, for example, describes an eccentric screw pump in which a measuring sensor is assigned to the stator, with which compressions and / or movements of the stator or the elastic material are measured during the rotation of the rotor.

[0006] DE 10 2018 113 347 A1 describes a method for determining or monitoring the condition of an eccentric screw pump. The method provides the temporal progression of an operating parameter of the pump that pulsates periodically at the pump frequency or a multiple of the pump frequency, and whose pulsation amplitude depends on the condition of the eccentric screw pump. In particular, the pulsation amplitude of the pressure pulsation is determined, and the condition of the eccentric screw pump, in particular the stator, is determined by comparing it with one or more reference values.

[0007] However, there is also a need to detect or monitor wear or damage to other components of a progressing cavity pump. This applies, among other things, to the connections within the rotating unit, e.g., the articulated connections of the coupling rod. This is where the invention comes in.

[0008] The invention is based on the object of creating a pump that enables reliable monitoring of the condition, e.g., the wear of connections within the rotating unit, using simple means. Preferably, reliable monitoring of the wear of joints within the rotating unit of an eccentric screw pump should be enabled.

[0009] To achieve this object, the invention teaches that, in a generic pump of the type described above, a monitoring device is provided or the pump is equipped with a monitoring device which is designed to monitor the state of the connection by determining a phase shift occurring in the connection between the first angle of rotation and the second angle of rotation. Preferably, the monitoring device is designed to monitor the wear state of the connection between the first shaft and the second shaft by determining a phase shift occurring in the connection between the first angle of rotation and the second angle of rotation due to wear. Alternatively, it is also possible to monitor other damage or defects which are present or occur in the area of ​​the connection independently of wear. The connection to be monitored can be a separable (ieThe connection can be a dismountable (e.g., detachable) and / or articulated connection, e.g., a joint or a separable connection on the rotor head. This also includes plug-in and / or flexible connections, e.g., a connection via a plug-in shaft or a flexible coupling rod. The first shaft is preferably a centrally or circularly rotating shaft that rotates around a fixed axis. The second shaft can also be such a centrally rotating shaft. However, the second shaft can also rotate eccentrically relative to the first shaft.

[0010] Ideally, not only can wear and tear be monitored or damage detected, but also predictions can be made in the sense of predictive maintenance ("condition monitoring" / "predictive maintenance"). This will be discussed in more detail below.

[0011] The invention is particularly preferably implemented in an eccentric screw pump in which a rotating rotor is provided as the pump element, which rotates within a stator (e.g. made of elastic material). In this eccentric screw pump, a coupling rod can be provided within the rotating unit, which is arranged between the first shaft (e.g. connecting shaft or drive shaft) and the rotor or rotor head (as the second shaft), wherein the coupling rod ensures or enables the eccentricity between the first shaft and the second shaft (e.g. rotor head) and wherein the coupling rod is connected, for example, with a first (drive-side) joint to the first shaft (e.g. connecting shaft / drive shaft) and with a second (rotor-side) joint to the second shaft (e.g. the rotor head). In such an embodiment, the monitoring device is designed to monitor the state (e.g.wear condition) of the first joint and / or the second joint by determining a phase shift occurring (e.g. due to wear) in one joint or in both joints between the first angle of rotation and the second angle of rotation.

[0012] The invention is based on the recognition that the connections or couplings within the rotating unit, e.g., the joints, are subject to wear or damage, and that such wear or damage can be detected by monitoring or analyzing a phase shift between the first shaft (e.g., the drive shaft) and the second shaft (e.g., the rotor head). Damage or wear within a joint can lead to the rotor "lagging" relative to the drive shaft, i.e., the torque acting on the rotor causes wear dependent on the direction of rotation, which leads to a phase shift between the rotation of the drive shaft and the rotor. This phase shift can be detected and monitored according to the invention.

[0013] This applies in particular to designs in which one or more joints enable free movement in multiple directions. These can be, for example, pin joints, ball joints, cardan joints, universal joints, or the like. A pin joint has, on the one hand, a plug-in socket and, on the other hand, a pin engaging in the plug-in socket, as well as a connecting pin that fixes the pin in the plug-in socket. During operation, wear can cause the joint pin to work its way through the rotor head or the plug-in socket / coupling rod bushing, or to be abraded itself. When the pin is incorporated into the coupling rod or the rotor head, or in the case of severe pin wear, the aforementioned "lagging" of the rotor relative to the drive shaft occurs, and thus to the phase shift observed according to the invention. By determining orMonitoring this phase shift therefore provides direct information about the condition of the rotating unit, and in particular, the condition of its connections, such as joints. This allows maintenance / repairs to be carried out in a timely manner and joint failure to be avoided. Predictions can be made, allowing timely maintenance or repairs to be carried out. This allows maintenance work to be excellently planned and optimized, and, in particular, timely measures to be taken to prevent damage.

[0014] The aforementioned advantages can be achieved not only with eccentric screw pumps with a coupling rod and multiple (pin) joints, but also with other eccentric screw pump designs, e.g., designs with only one joint or designs with a flexible coupling rod without (dismountable) joints. Furthermore, the advantages can be achieved not only with eccentric screw pumps, but also with other types of positive displacement pumps with rotating shafts, and in particular, connections between rotating shafts.

[0015] In practice, the joints of the progressing cavity pump are separated from the fluid being pumped by suitable means, such as sleeves. If such a sleeve becomes damaged, the fluid can penetrate into the area of ​​the joint and cause increased wear. Especially in such cases, the monitoring system according to the invention can prevent damage and consequential damage.

[0016] What is particularly interesting is the fact that joint wear can be easily determined / monitored and optionally predicted without dismantling the pump or the relevant components.

[0017] In a preferred embodiment, the monitoring device for monitoring the condition of the pump has one or more sensors, which generate one or more signals that depend on the first angle of rotation and / or the second angle of rotation and / or the phase shift. The monitoring device can have an evaluation unit, with which in particular the signals from the sensors are processed and evaluated. The sensors can be, for example, position sensors. Such position sensors are, for example, inductive, capacitive, magnetic or optical sensors. In this preferred embodiment, the phase shift is therefore measured directly via the sensors. For example, it is possible to provide a first sensor in the area of ​​the first shaft (e.g. drive shaft / stub shaft) and a second sensor in the area of ​​the second shaft (e.g.Rotor / rotor head) so that the phase shift between the two rotation angles can be determined directly from the signals of the two sensors (e.g., distance sensors). (Stationary) Hall sensors can be used as sensors, for example, with a magnet attached to the respective shaft.

[0018] The time interval at which a defined measurement point is detected on both sensors per revolution is set as the starting point / zero angle when the pump is new or during commissioning. With increasing wear, the time interval between the two detection points increases or decreases at the same speed. By relating the time difference between the detections to the length of a period (revolution), the phase shift between the two signals can be directly calculated. This phase shift serves as a measure of the wear of the joint(s).

[0019] Furthermore, determining a phase shift between two angles of rotation does not necessarily mean determining an absolute value for the phase shift. Rather, it may be sufficient to determine the time intervals and evaluate them directly. In this case, the time intervals or time differences represent the phase shift, so that the current state of the connection can be deduced from the time differences. However, it is generally advisable to also consider the speed of the respective shaft, which can vary during operation, so that the time intervals, taking the respective speed into account, are incorporated into the determination of the phase shift.

[0020] Even if a progressive cavity pump often has a coupling rod with two connecting joints or joints between the drive shaft and the rotor, it may be sufficient to work with a first sensor in the area of ​​the first shaft and a second sensor in the area of ​​the second shaft (rotor), so that the "total wear" of the two joints is determined via the phase shift.

[0021] In a possible further development, an additional (third) sensor can be provided, e.g. in the area of ​​the coupling rod, so that on the one hand a first phase shift between the drive shaft and the coupling rod and on the other hand a second phase shift between the coupling rod and the rotor can be determined. In this way, the wear of the two joints can be determined / monitored selectively and separately. In principle, two detection points, e.g. two sensors, are sufficient. Optionally, it is possible to use multiple detection points or sensors for multiple connections. In the case of N connections (e.g. couplings or joints), N+1 detection points, e.g. sensors, are used.

[0022] In a modified embodiment, a single sensor may be sufficient to monitor a connection between the first and the second shaft, which sensor is arranged directly in the area of ​​the connection and measures a value from which the phase shift can be determined.

[0023] The invention is preferably implemented in the described embodiment with a coupling rod that is connected on both sides by joints to the drive shaft / stub shaft on the one hand and the rotor on the other. However, the invention can also be implemented in the same way in eccentric screw pumps that only use a single joint or even non-articulated connections, e.g., in eccentric screw pumps with a flexible shaft or flexible components within the rotating unit.

[0024] Alternatively or additionally, the principle according to the invention can also be implemented in the area of ​​the drive of the eccentric screw pump, e.g. in the area of ​​the connection between a drive shaft and a stub shaft. For example, the (electric) drive of an eccentric screw pump can be equipped with an integrated drive shaft that is connected to another shaft via a connection, which is referred to as a connecting shaft or also as a stub shaft. The stub shaft can optionally in turn be connected to a coupling rod or another element to compensate for the eccentricity of the rotor. In the event of wear or damage, a phase shift can also occur between the drive shaft and the stub shaft, which can be monitored in the manner according to the invention, for example by arranging sensors in the area of ​​the drive shaft and / or the stub shaft.

[0025] As already described, the monitoring device can be equipped with or connected to an evaluation unit that, for example, processes and evaluates the signals from the sensors. Furthermore, a threshold value for the phase shift can be stored in the evaluation unit so that, for example, a message is generated during operation when the threshold value is reached or exceeded, e.g., a visual and / or acoustic alarm signal. Alternatively, however, it is also possible to work without a fixed threshold. This makes it possible to store one or more comparison values ​​in the evaluation unit, e.g., during operation of a new pump or new connection. During operation, the temporal development of the phase shift can then be monitored, allowing conclusions to be drawn about the condition of the connection.

[0026] This preferably allows for the pump's condition to be continuously determined and, based on the determined condition data, to use an algorithm to predict the condition and / or the timing of maintenance appointments. An algorithm is stored in the evaluation unit that can be used to make predictions about potential maintenance requirements based on the data. The evaluation unit can therefore be configured for a further analysis step, namely a prediction, thus enabling predictive maintenance and repair.

[0027] Optionally, the evaluation unit can also be set up to analyze the phase shift (i.e. the difference in the angle of rotation) taking into account the rotational speed of the first shaft and / or the second shaft. In particular, there is the possibility that the phase shift is speed-dependent or behaves differently at different rotor speeds. In this respect, it can be useful to take the speed into account when evaluating the phase shift. This is usually easily possible because the speed can be recorded using the measuring devices provided and is usually included in the determination of the phase shift anyway by relating the time difference of the respective signals to the length of the period (revolution) in order to determine the phase shift between the signals. In addition, the phase shift can then also be considered as a function of this speed during the evaluation.The speed is determined by the time difference between the signals. Alternatively or additionally, it is possible to determine the phase shift taking into account the torque and / or the axial force (of the shafts or the respective shaft). This option is particularly interesting when a joint or coupling rod made of a material other than metal, e.g. an elastomer, is used, i.e. with materials that are elastically deformable, as the angle of rotation could then change with the speed or pressure. It is then useful to also record and take into account the torque, because with elastically deformable components the torque would generally be responsible for the phase shift, so that corresponding deformations can be compensated for in the evaluation using the torque.The axial force can also be relevant, as it influences the extent to which a part can work into a material not only in the radial direction, but also in the axial direction. In such a case, changing pressure conditions on the suction and pressure sides could lead to a reversal of the direction of the axial force, i.e. the rotor is pushed or pulled in the opposite direction and the phase angle returns to its original position. In this case, work-in or wear can occur in the other direction, so the evaluation of the axial force can optionally be advantageous. The preferred option of determining the phase shift as a function of speed and / or pressure can be implemented not only for joints, but also for other types of connections.

[0028] Overall, the invention enables simple and flawless monitoring of the condition of connections within the rotating unit of a pump, e.g., the condition of the joints of an eccentric screw pump. This allows for timely detection of incipient wear, e.g., in pin joints where the pin is penetrating the other joint part or is itself subject to wear. Detection can be achieved using inexpensive standard sensors. Using a sensor with a switching output, the signals can be evaluated using existing industrial circuits. At the same time, the pump speed can be determined from the signals. This means that when the phase shift and the speed are monitored simultaneously, no additional sensors are required.

[0029] Particularly preferably, the monitoring device or the evaluation unit is designed in such a way that not only current status data, e.g. a specific wear or damage, is recorded, but in particular predictions can also be made about the status of the pump or a connection and / or predictions about the time of maintenance measures. The evaluation unit is therefore equipped with an algorithm with which predictions about the maintenance requirement can be made from the continuously recorded data. For this purpose, display devices can optionally be provided on the pump with which certain states are indicated acoustically and / or visually. Particularly preferably, the monitoring device is equipped with an interface for data transmission or data retrieval or an interface so that data and / or predictions can be made available, e.g. via computers and / or end devices (e.g.In this way, information can be received and, if necessary, visualized even at greater distances from the pump via, for example, end devices. This allows maintenance technicians, for example, to quickly and easily obtain current information on the status of individual pumps or individual components and to plan maintenance work. The invention therefore enables both condition monitoring and predictive maintenance to be implemented. Production and pump data can be collected centrally and, if necessary, accessed via any end device. This makes it easy to monitor and systematically optimize production.

[0030] The monitoring system not only predicts damage or other conditions, but also generates warning messages. Maintenance predictions allow for optimized planning of maintenance intervals, thus minimizing maintenance costs. Optionally, maintenance can be performed dynamically as needed rather than at intervals. This type of flexible maintenance and repair also reduces downtime, enabling efficient production for the pump operator. Furthermore, optimized maintenance based on the determined condition data extends the service life of the pump and / or increases its efficiency, thus improving efficiency.

[0031] The monitoring device and the evaluation unit can be part of the pump or can be arranged directly on the pump. Alternatively, the monitoring device or parts of the monitoring device and / or the evaluation unit can also be arranged spatially separate from the pump and, for example, integrated into a (central) control device or a (central) computer. In particular, it is possible for the monitoring device of the pump to only record the necessary data and, if necessary, to temporarily store it. The data can be transmitted via the aforementioned interface, e.g. wirelessly or wired, to a computer and / or a terminal device, so that the aforementioned algorithm for evaluation can run on a computer and / or a terminal device, for example.

[0032] The subject matter of the invention is not only the pump described, but also a method for monitoring the operation and wear of such a pump. During operation, the first shaft rotates at a first angle of rotation and the second shaft rotates at a second angle of rotation, each relative to a common zero angle. According to the invention, the condition of the connection or connections is monitored by determining or monitoring a phase shift occurring in the connection between the first angle of rotation and the second angle of rotation. In a preferred development of the method according to the invention, the measures described in connection with the pump are protected individually and in combination.

[0033] The invention will be explained in more detail below with reference to drawings which merely represent an exemplary embodiment. Fig. 1 an eccentric screw pump with a monitoring device for monitoring the condition, for example wear condition in a simplified side view, Fig. 2 an enlarged section of Fig. 1 in the area of ​​a joint, Fig. 3A, 3B each show a cross-section in the area of ​​the joint in different wear states and Fig. 4A, 4B measurement signals for the joint after Fig. 3A or 3B, Fig. 5 a view from Fig. 1 in the area of ​​the drive shaft.

[0034] In Fig. 1 An eccentric screw pump is shown, which has a stator 1 made of an elastic material and a rotor 2 rotating in the stator 1, wherein the stator 1 is surrounded by a stator casing 3. Furthermore, the pump has a suction housing 4 and a connection nozzle 5, which is also referred to as a pressure nozzle 5. The pump also has a pump drive 6, which acts on the rotor 2 via a coupling rod 7. The coupling rod 7 is connected to the drive shaft via a drive-side coupling joint 8 and to the rotor 2 or the rotor head via a rotor-side coupling joint 9.

[0035] The coupling joints 8, 9 are each designed as pin joints in this embodiment, each having on the one hand a plug-in receptacle 10 and on the other hand a pin 11 engaging in the plug-in receptacle 10 and a connecting pin 12 fixing the pin 11 in the plug-in receptacle 10 (see Fig. 2 ).

[0036] A drive shaft or connecting shaft 18 driven by the drive forms a first shaft W1 and the rotor 2 or rotor head forms a second shaft W2, wherein the first shaft W1 is connected to the second shaft W2 via the connecting joints 8, 9 as connections V. During operation, the first shaft W1 (drive shaft) rotates at a first angle of rotation and the second shaft W2 (rotor head) rotates at a second angle of rotation, in each case relative to a common zero angle. In the new state, the phase shift between the first angle of rotation and the second angle of rotation is zero or such a phase shift can be defined as a zero angle. With a monitoring device 13 provided according to the invention, a phase shift between the first angle of rotation and the second angle of rotation, which may occur, for example, due to wear, is determined and monitored.For this purpose, the two sensors 15, 16, which are only indicated in the illustrated embodiment, can be provided, one in the area of ​​the first shaft W1 and the other in the area of ​​the second shaft W2. With the help of these sensors 15, 16, which can be designed, for example, as distance sensors, the phase shift can be determined directly. For this purpose, reference is also made to the . Fig. 3A und 3B as well as Fig. 4A und 4B referred to. The Fig. 3A and 4A each show a new condition and the Fig. 3B and 4B each a wear condition of a connection V according to the invention, e.g. a pin joint 8, 9.

[0037] The two sensors 15, 16 each generate switching signals which are Fig. 4A only have a very short time interval Δ T1. This time interval Δ T1 can form the starting point for monitoring in the new state, ie, such a phase shift can be stored as a reference value or comparison value in an evaluation unit 14.

[0038] In contrast, Fig. 4B The signal progression with increasing wear is determined by increasing the time interval ΔT2 between the two detections. By relating the time difference of these signals to the length of a period (revolution), the phase shift between the two signals can be determined, so that the phase shift can be used as a measure of the joint's wear. This monitoring is carried out by the monitoring device 13, which includes, in particular, the sensors 15, 16 and the evaluation unit 14.

[0039] Furthermore, in Fig. 5 in an excerpt from Fig. 1 It is shown that in such an eccentric screw pump, a drive shaft 17 integrated into the drive 6 does not have to be directly connected to the drive-side coupling joint 8. Instead, in this embodiment, the drive shaft 17 integrated into the drive 6 is connected to a connecting shaft 18, which is also referred to as a plug-in shaft or, in this embodiment, is designed as a plug-in shaft. This plug-in shaft 18 is connected in the embodiment as the first shaft W1 via the coupling joints 8, 9 and the coupling rod 7 to the rotor 2 or rotor head as the second shaft W2. Fig. 1 and 5 Also shown as an example are a connecting housing 19 and a shaft seal 20, e.g. a mechanical seal, in the area between drive 6 and housing 4.

[0040] Furthermore, it is also possible to implement the inventive principle in the area of ​​the connection between the drive shaft 17 and the plug-in shaft 18. In this case, the drive shaft 17 would be the first shaft and the plug-in shaft 18 the second shaft, so that the condition of the connection between these two shafts can be monitored. Details are not shown in the figures.

Claims

1. A pump for conveying a medium, in particular, a liquid or a solid-liquid mixture, comprising at least one drive (6), a first shaft (W1) and a second shaft (W2) driven by the first shaft (W1) in a rotating manner, which is connected to a pump element (2) or is part of a pump element (2), wherein the first shaft (W1) is connected to the second shaft (W2) by means of at least one connection (V), wherein, during operation, the first shaft (W1) rotates at a first angle of rotation and the second shaft (W2) rotates at a second angle of rotation, each with reference to a common zero angle, characterized by a monitoring device (13) which is designed to monitor the condition of the connection (V) by detecting a phase shift occurring in the connection between the first angle of rotation and the second angle of rotation.

2. The pump according to Claim 1, characterized in that the connection (V) is formed as a separable and / or articulated connection, for example, as a joint or coupling joint (8, 9).

3. The pump according to Claim 1 or 2, characterized in that the monitoring device (13) is designed to monitor the wear condition of the connection (V) or connections by detecting a phase shift between the first angle of rotation and the second angle of rotation occurring due to wear in the connection (V).

4. The pump according to any one of the Claims 1 to 3 in the embodiment of an progressive cavity pump, comprising at least a stator (1) and a rotor (2) rotating in the stator as a pump element.

5. The pump according to Claim 4, comprising a coupling rod (7) between the first shaft (W1) and the rotor (2) as the second shaft (W2), wherein the coupling rod (7) is connected to a first (drive-side) joint (8) with the first shaft (W1) (e.g., connecting shaft / drive shaft) and to a second (rotor-side) joint (9) with the rotor (2).

6. The pump according to Claim 5, characterized in that the monitoring device (13) is designed to monitor the wear condition of the first joint (8) and / or the second joint (9) by determining a phase shift between the first angle of rotation and the second angle of rotation occurring due to wear in one joint (8, 9) or in both joints (8, 9).

7. The pump according to any one of the Claims 1 to 6, characterized in that the joint (8, 9) or joints (8, 9) is / are formed as a pin joint or pin joints, wherein the pin joint comprises an insertion receptacle (10) on the one hand and, on the other hand, a pin (11) engaging the insertion receptacle (10) and a connecting pin (12) fixing the pin (11) within the insertion receptacle (10).

8. The pump according to any one of the Claims 1 to 7, characterized in that the monitoring device (13) comprises one or a plurality of sensors (15, 16) which generate one or a plurality of signals depending on the first angle of rotation and / or the second angle of rotation and / or the phase shift.

9. The pump according to any one of the Claims 1 to 8, characterized in that the monitoring device (13) comprises an evaluation unit (14) or is connected to an evaluation unit (14) with which, in particular, the signals of the sensors (15, 16) are processed and evaluated.

10. The pump according to Claim 8 or 9, characterized in that the sensor(s) (15, 16) are designed as position sensors, for example, as inductive, capacitive, magnetic or optical sensors.

11. The pump according to any one of the Claims 8 to 10, characterized in that at least one first sensor (15) is arranged in the region of the first shaft (W1) and a second sensor (16) is arranged in the region of the second shaft (W2) or of the pump element (2).

12. The pump according to any one of the Claims 9 to 11, characterized in that a threshold value or one or a plurality of comparative values for the phase shift can be stored in the evaluation unit (14) and that, during operation, when the threshold value is reached or exceeded or when a temporal development of the phase shift is detected that deviates from a previously determined characteristic development, a message can be generated, for example, a visual and / or acoustic alarm signal.

13. The pump according to any one of the Claims 9 to 12, characterized in that an evaluation algorithm is stored in the evaluation unit (14) with which predictions of the condition of the connection (V) and / or predictions of maintenance times can be generated from continuously determined data.

14. The pump according to any one of the Claims 9 to 13, characterized in that the monitoring device (13) is equipped or connected with a display device by means of which status information and / or warning signals can be displayed, e.g. acoustically or optically and / or that the monitoring device (13) is equipped or connected with an interface via which status data and / or predictions and / or warning messages are transmitted to external devices, e.g. computers, terminal devices or the like.

15. The pump according to any one of the Claims 1 to 14, characterized in that the monitoring device (13) or the evaluation unit (14) is designed to analyse the phase shift taking into account the rotational velocity of the first shaft (W1) and / or the second shaft (W2).

16. A method for monitoring the operation or wear of a pump according to any one of the Claims 1 to 15, wherein, during operation, the first shaft rotates at a first angle of rotation and the second shaft rotates at a second angle of rotation, each with reference to a common zero angle, characterized in that the monitoring device is used to monitor the condition, for example, the wear condition of the connection, by determining a phase shift between the first angle of rotation and the second angle of rotation, for example, due to wear in the connection.

17. The method according to Claim 16, characterized in that the condition of the pump or the condition of a connection is continuously determined and that predictions about the condition of the pump or the connection and / or predictions about maintenance times are generated from the determined condition data by means of an algorithm.

18. The method according to Claim 16 or 17, characterized in that condition data, warning messages and / or maintenance predictions are transmitted via an interface to external devices, for example, computers, terminal devices or the like, or are queried by them.