STATE DETECTION ON ECCENTRIC SCREW PUMPS

Abstract

An eccentric screw pump hasa pump housing having a pump inlet opening and a pump outlet opening, a stator disposed in the pump housing, a rotor disposed in the stator, a drive unit comprising a drive motor and a driveshaft which for transmitting a torque connects the drive motor to the rotor, wherein the rotor for a rotating movement about a rotating axle is guided in the stator, a state sensor for detecting a state variable of the eccentric screw pump, where the state sensor, for detecting a state variable on the rotor or on the driveshaft, is disposed on the rotor or the driveshaft, or is connected to the rotor or the driveshaft by means of a signal line and is disposed so as to be spaced apart from the rotor or the driveshaft.

Claims

1-19. (canceled)

20. An eccentric screw pump, comprising: a pump housing having a pump inlet opening and a pump outlet opening; a stator disposed in the pump housing; a rotor disposed in the stator, wherein the rotor is adapted for rotational movement about a rotating axis and is guided in the stator; a drive unit comprising a drive motor and a drive shaft transmitting a torque and connecting the drive motor to the rotor; and a state sensor for detecting a state variable of the eccentric screw pump; wherein the state sensor is disposed within the rotor or within the drive shaft and is connected to a state sensor data transmission module for wirelessly transmitting state data to a data receiver outside the eccentric screw pump; and wherein: the state sensor and the state sensor data transmission module are connected to an energy converter disposed on the rotor or on the drive shaft and configured for converting kinetic or thermal energy acting on the energy converter into electric energy; or the state sensor is connected to the rotor or the drive shaft by a signal line and is disposed so as to be spaced apart from the rotor or the drive shaft.

21. The eccentric screw pump as claimed in claim 20, wherein the state sensor is connected so as to be wired to an electronic evaluation unit by way of a sensor cable; and wherein the sensor cable runs within a portion of the drive shaft and/or within a portion of the rotor; or wherein the sensor cable runs through the drive shaft.

22. The eccentric screw pump as claimed in claim 20, wherein: the drive shaft is a wobble shaft which at an end thereof that points toward the drive motor is connected to the drive motor for rotation about a drive axis; and at an end thereof that points toward the rotor is connected to the rotor for rotation about a rotor axis and for a superimposed rotation about a stator axis spaced apart from the rotor axis.

23. The eccentric screw pump as claimed in claim 22, wherein the wobble shaft has a wobble shaft central portion, a first universal joint, and a second universal joint, wherein: the first universal joint is inserted between the wobble shaft central portion and the drive motor; and the second universal joint is inserted between the wobble shaft central portion and the rotor.

24. The eccentric screw pump as claimed in claim 23, wherein a sensor cable is routed: into the first and/or the second universal joint; through the first universal joint; or about the first and/or the second universal joint.

25. The eccentric screw pump as claimed in claim 23, wherein the first universal joint is enclosed by a first sealing boot and the second universal joint is enclosed by a second sealing boot, or wherein the first and the second universal joint and the wobble shaft are enclosed by a sealing sleeve; and in that, for detecting the pressure in the first and/or second sealing boot or in the sealing sleeve, a pressure sensor is disposed in the first and/or the second sealing boot or in the sealing sleeve; or a pressure line is routed into the first and/or the second sealing boot or into the sealing sleeve, and a pressure sensor is fluidically connected to the pressure line; and the pressure sensor for signal transmission is connected to an evaluation unit and the pressure sensor is configured for detecting the pressure within the first and/or the second sealing boot or within the sealing sleeve.

26. The eccentric screw pump as claimed in claim 20, wherein the state sensor is connected to an electronic evaluation unit and the electronic evaluation unit is configured for: determining a variance of an actual state detected by the state sensor by the state sensor data from a predetermined target state; comparing this determined variance with a predetermined permissible variance; and when the determined variance exceeds the permissible variance, emitting an alarm signal.

27. The eccentric screw pump as claimed in claim 26, wherein the electronic evaluation unit is configured for: receiving a state sensor signal as the actual state; and comparing the state sensor signal with a stored normal state sensor signal as the target state, wherein the electronic evaluation is further configured for: calculating the determined variance as the difference between the state sensor signal and the stored normal state sensor signal; utilizing a predetermined permissible variance value as the predetermined permissible variance; and emitting an alarm signal as a value alarm signal.

28. The eccentric screw pump as claimed in claim 26, wherein the electronic evaluation unit is configured for: receiving state sensor signals; determining from at least two temporally sequential state sensor signals a state variation value as the actual state; and comparing the state variation value with a stored normal state variation value as the target state, wherein the electronic evaluation is further configured for: calculating the determined variance as a difference between the state variation value and the stored normal state variation value; utilizing a predetermined permissible variance variation value as the predetermined permissible variance; and emitting a variation alarm signal as the alarm signal.

29. The eccentric screw pump as claimed in claim 26, wherein the electronic evaluation unit is configured for: receiving state sensor signals; determining from at least three temporally sequential state sensor signals a state variation speed as the actual state; and comparing the state variation speed with a stored normal state variation speed as the target state, wherein the electronic evaluation is further configured for: calculating the determined variance as the difference between the state variation speed and the stored normal state variation speed; utilizing a predetermined permissible speed variance as the predetermined permissible variance; and emitting a variation speed alarm signal as the alarm signal.

30. The eccentric screw pump as claimed in claim 26, wherein the electronic evaluation unit is configured for: comparing a plurality of temporally sequential actual states with a plurality of temporally sequential target states; calculating from the comparison a variance characteristic value as the determined variance; and utilizing a predetermined permissible variance characteristic value as the predetermined permissible variance.

31. The eccentric screw pump as claimed in claim 26, wherein the eccentric screw pump has a rotor having a conical envelope and a conically tapered stator interior, and the rotor and the stator are adjustable relative to one another in the axial direction by an axial actuating drive, and wherein the electronic evaluation unit for signal transmission is connected to the axial actuating drive and configured for: actuating the actuating drive so as to carry out an axial adjustment between the rotor and the stator; and detecting during the axial adjustment procedure a plurality of temporally sequential state sensor signals of the state sensor.

32. The eccentric screw pump as claimed in claim 20, wherein the energy converter is selected from: a converter based on an electromagnetic induction principle, which converts a relative rotating movement of the rotor or of the wobble shaft in relation to a pump housing into electric energy; a converter based on an electromagnetic induction principle, which converts a reciprocating acceleration of the rotor or of the wobble shaft resulting from the rotation of the rotor or of the wobble shaft about a rotor axis and from the rotation of the rotor about an eccentric axis into electric energy; or a converter based on a thermo-electric principle, which converts a temperature gradient into electric energy, wherein the converter is disposed in a region exposed to a temperature gradient between the conveyed medium and a pump component.

33. The eccentric screw pump as claimed in claim 20, further comprising two state sensors disposed on two mutually spaced apart positions disposed on the rotor, and the positions have a phase shift of a measured state variable.

34. The eccentric screw pump as claimed in claim 20, wherein the state sensor comprises: a temperature sensor; a pressure sensor; a vibration sensor; or an acceleration sensor.

35. A method for controlling an eccentric screw pump comprising a pump housing having a pump inlet opening and a pump outlet opening, the method comprising the steps of: driving a rotor for a rotational movement about a rotating axis in a stator by a drive unit and a drive shaft; pumping a medium from a pump inlet through the stator to a pump outlet by way of a displacement effect between the rotor and the stator; and detecting a state variable of the eccentric screw pump, wherein: the state variable is detected by means of a state sensor which is: disposed within the rotor or within the drive shaft and connected to a state sensor data transmission module for wirelessly transmitting state data to a data receiver outside the eccentric screw pump, wherein the state sensor and the state sensor data transmission module for receiving electric energy are connected to an energy converter disposed on the rotor or on the drive shaft and configured for converting kinetic or thermal energy acting on the energy converter into electric energy; or connected to the rotor or the drive shaft by means of a signal line and is disposed so as to be spaced apart from the rotor or the drive shaft; and wherein the state variable is detected on the rotor or on the drive shaft.

36. The method as claimed in claim 35, wherein: the eccentric screw pump has a rotor having a conical envelope and a conically tapered stator interior, and the rotor and the stator are adjusted relative to one another in the axial direction by means of an axial actuating drive; the rotor and the stator are axially mutually adjusted by means of the axial actuating drive; a plurality of temporally sequential state sensor signals of the state sensor are detected during the axial adjustment procedure; and the state variable is detected during the pumping procedure and the axial adjustment procedure is carried out during the pumping procedure.

37. An eccentric screw pump, comprising: a pump housing having a pump inlet opening and a pump outlet opening; a stator disposed in the pump housing; a rotor disposed in the stator; a drive unit comprising a drive motor and a drive shaft mechanically coupled with the rotor for transmitting a torque to the rotor, wherein the rotor is guided in the stator for rotational movement about a rotating axis; and a state sensor for detecting a state variable of the eccentric screw pump, wherein the state sensor is disposed within the rotor or within the drive shaft and is connected to a state sensor data transmission module for wirelessly transmitting state data to a data receiver outside of the eccentric screw pump; wherein the state sensor and the state sensor data transmission module for receiving electric energy are connected to an energy converter disposed on the rotor or on the drive shaft, the energy converter being configured for converting kinetic or thermal energy acting on the energy converter into electric energy; or wherein the state sensor is connected by a signal line to the rotor or the drive shaft and is disposed so as to be spaced apart from the rotor or the drive shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Preferred embodiments of the invention will be explained by means of the appended figures, in which:

[0056] FIG. 1 shows a longitudinal sectional view of an eccentric screw pump according to the invention;

[0057] FIG. 2 shows a longitudinal sectional view of a fragment of a first embodiment of the eccentric screw pump according to the invention;

[0058] FIG. 3 shows a view according to FIG. 2 of a second embodiment of the invention;

[0059] FIG. 4a shows a longitudinal sectional partial view of a third embodiment of the invention;

[0060] FIG. 4b shows a view according to FIG. 4a of a fourth embodiment of the invention;

[0061] FIG. 4c shows a view according to FIG. 4a of a fifth embodiment of the invention;

[0062] FIG. 4d shows a view according to FIG. 4a of a sixth embodiment of the invention;

[0063] FIG. 4e shows a view according to FIG. 4a of a seventh embodiment of the invention;

[0064] FIG. 4f shows a view according to FIG. 4a of an eighth embodiment of the invention;

[0065] FIG. 4g shows a view according to FIG. 4a of a ninth embodiment of the invention;

[0066] FIG. 4h shows a view according to FIG. 4a of a tenth embodiment of the invention;

[0067] FIG. 4i shows a view according to FIG. 4a of an eleventh embodiment of the invention;

[0068] FIG. 4j shows a view according to FIG. 4a of a twelfth embodiment of the invention;

[0069] FIG. 4k shows a view according to FIG. 4a of a thirteenth embodiment of the invention;

[0070] FIG. 5a shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a first embodiment;

[0071] FIG. 5b shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a second embodiment;

[0072] FIG. 5c shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a third embodiment;

[0073] FIG. 6a shows a schematic illustration of the profile of three characteristic measured values which are recorded on the wobble shaft or the rotor, over the operating time of an eccentric screw pump;

[0074] FIG. 6b shows a typical schematic profile of three temperatures recorded on the rotor over time;

[0075] FIG. 6c shows a typical schematic profile of the movement of a sensor fastened to the rotor in three directions over time, in a normal operating state; and

[0076] FIG. 6d shows a typical schematic profile of the movement of a sensor fastened to the rotor in three directions over time, in an operating state of a pump having progressed wear.

DETAILED DESCRIPTION OF THE EMBODMENTS

[0077] Shown in FIG. 1 is the typical construction of an eccentric screw pump. The pump has a stator 10 which has a cavity in the form of a spiral screw path having two turns that extends along a stator longitudinal axis A. The stator 10 typically comprises a metal pipe 11 or any other stable enveloping construction which encloses an elastomer casing 12 which on the inside configure a cavity having the screw geometry. A rotor 20, which extends along a rotor longitudinal axis B which runs so as to be offset in parallel to the stator longitudinal axis A by the so-called “eccentricity,” is disposed in the stator cavity. Eccentric screw pumps can be configured with rotors and stators with various numbers of turns. In principle, the number of turns of the rotor will always exceed the number of turns of the stator by one turn in order to meet the functional principle.

[0078] The stator interior and the rotor can taper in the axial direction, i.e., in the pumping direction (not illustrated), such that the end of the rotor and of the stator interior that points toward an inlet opening 1 has a larger cross-sectional area than the end pointing toward the outlet opening 2. In such tapered rotors and stators (typically having a conical envelope, or being equipped with a conically tapered interior, respectively), the rotor and the stator in this instance are disposed so as to be axially mutually displaceable (axial movement Ax). An axial actuation in this instance is preferably possible during the rotating movement Ro of the rotor. As a result, play due to wear, or insufficient pre-tensioning of the rotor, in the stator, respectively, can be compensated for, on the one hand, in that the rotor is driven further into the stator. Moreover, a start-up behavior of the pump can be optimized by the axle adjustment, for example in that axial adjustment is performed by means of the state variables as a function of the pumping behavior. For example, a response to different viscosities of the conveyed medium is possible.

[0079] The rotor 20 by a wobble shaft 30 is set in rotation about the rotor longitudinal axis B of said rotor 20. The wobble shaft 30 here is inserted between the rotor and a drive input shaft which by way of a belt drive 41 is driven by a drive motor 40, said wobble shaft 30 transmitting a rotating movement of the drive motor 40 to the rotor 20. The wobble shaft 30 here extends from a drive input end 30a, which in the rotating manner is mounted in an inlet housing 50, to a drive output end 30b which is connected to the rotor. The wobble shaft 30 at the drive output end 30b performs a combined movement which is composed of a rotation about the rotor longitudinal axis B and of a rotation of the rotor longitudinal axis B about the stator longitudinal axis A. At this drive output end, the wobble shaft can be guided by means of an eccentric mounting, which is embodied by two rotary bearings having eccentrically offset axes, or said wobble shaft may be without guidance so that the movement of the drive output end of the wobble shaft is defined by the guidance of the rotor in the stator.

[0080] The wobble shaft 30 on the drive input end 30a has an input universal joint 31, and on the drive output end has an output universal joint 32. A shaft portion 33, which connects the two universal joints 31, 32, extends between the two universal joints 31, 32. The input universal joint 31 is connected to the drive input shaft, and by way of the belt drive connected to the output shaft of the drive motor 40. The output universal joint 32 is connected to the rotor.

[0081] The entire wobble shaft 30 is disposed in an inlet housing 50 and is surrounded by the wash of a medium to be pumped, which by way of an inlet opening 51 flows into the inlet housing 50. This represents the suction side of the pump. Therefore, the wobble shaft is entirely surrounded by a protective casing 36 which extends across the input universal joint 31, the shaft portion 33, and the output universal joint 32.

[0082] The rotor 20 and the stator 10 extend from an inlet end 10a, which is fastened to the inlet housing, to an outlet housing 60, which is fastened to an outlet end 20a. An outlet opening 61 is disposed on the outlet housing 60, the conveyed medium from the pump flowing through said outlet opening 61, the latter representing the pressure side of the pump.

[0083] FIG. 2 shows a fragment which shows the wobble shaft, having the drive input shaft attached thereto and the rotor attached thereto in the fragment. In this embodiment, a sensor 101 is inserted in a bore 102 in the rotor, said bore 102 running in the radial direction to the rotor longitudinal axis B. The sensor can be, for example, a temperature sensor, an acceleration sensor, or a pressure sensor. The rotor 20 furthermore has a longitudinal bore 103 which extends along the rotor longitudinal axis B so as to be coaxial with the latter.

[0084] In the embodiment according to FIG. 2, the sensor 101 is connected by means of a sensor signal line 105 which runs through the longitudinal bore 103 in the rotor and, proceeding therefrom, opens into a flange longitudinal bore 34 in the connecting flange of the output universal joint 31, said flange longitudinal bore 34 running coaxially with the longitudinal bore 103. From this flange longitudinal bore 34, the sensor signal line 105 runs through a bore in the connecting flange of the output universal joint 31 to a position outside the universal joint 31, said bore extending in the radial direction to the rotor longitudinal axis B. The signal line 105 then runs outside the universal joint 31, outside the shaft portion 33 and outside the universal joint 32, but within the protective casing 31, to the input end of the wobble shaft 30. At this input end the signal line 105 runs in a manner analogous to that of the output end, first through a radial bore in the shaft portion-proximal connecting flange of the input universal joint to an axial bore in the drive input shaft-proximal connecting flange of the universal joint, and from there into a coaxial longitudinal bore in the drive input shaft. The sensor signal line can then be routed to a sensor signal rotary transmission unit which can be embodied in the form of a plurality of collector rings or the like, for example, so as to route the sensor signal from the rotating part of the eccentric screw pump to the outside, into a stationary part of the eccentric screw pump.

[0085] FIG. 3 shows a variant of the signal line routing. The figure shows a construction which is fundamentally identical to that of FIG. 2. Deviating therefrom however, the signal line in this variant is routed exclusively through axial longitudinal bores in the connecting flange of the universal output joint, the shaft portion, and the connecting flange of the universal input joint, so as to again open into the longitudinal bore in the driveshaft.

[0086] In this case, the signal line also runs through corresponding transverse bores in the pins of the two universal joints. It is to be understood here that the ducts in which the signal line runs, in terms of the dimensions thereof are embodied in a corresponding size such that the signal line remains free of shear effects and thus free of damage even in the wobbling movement arising during operation and during the bending of the universal joints.

[0087] The drive input shaft in FIG. 2 as well as in FIG. 3 on the input-proximal universal joint can be fastened by means of a central pin which extends partially or completely through the drive input shaft and is fastened to the universal joint so as to tension axially a conical interference fit between the drive input shaft and the universal joint. A further difference can be seen in that the signal line in the drive input shaft in the embodiment according to FIG. 2 is routed in an axially extending longitudinal groove in the shaft (e.g., in the manner of a feather key groove) and therefore lies laterally to the pin, whereas, in the embodiment according to FIG. 3, a hollow pin is provided, which runs in the drive input shaft embodied as a hollow shaft, and the signal line runs within the internal cavity of this hollow pin.

[0088] Different variants of the disposal of the sensor on the rotor are illustrated in FIGS. 4a-4k. It is to be understood in principle that the depicted sensors in these figures can be pressure sensors, temperature sensors, acceleration sensors, vibration sensors, or other sensors. It is furthermore to be understood that the variants of the disposal of the sensor depicted in FIGS. 4a-4k can also be combined with one another, specifically in such a manner that sensors of the same type can be disposed at different locations according to these variants, on the one hand, or that sensors of the same type can be used at different locations according to these variants, or that a plurality of sensors of different types can be disposed on one location shown in these variants. The principles of signal transmission and the energy supply of the sensors, which are shown in these variants according to FIGS. 4a-4k, can likewise be combined with one another.

[0089] FIG. 4a shows a disposal of the sensor 301 in the rotor, in which the sensor is inserted in the external surface of the rotor. This disposal of the sensor, as has been illustrated above by means of FIG. 2 3, can take place by a corresponding bore which extends radially in the rotor and a bore which extends axially in the rotor, if the sensor is intended to transmit the sensor signal by means of a signal line 305 and is optionally to be supplied with energy by way of an energy line 306 which runs in parallel to said signal line 305.

[0090] In general, a disposal of the sensor in the external surface of the rotor is advantageous because this position enables a revolving signal detection, on the one hand, and thus a signal detection across an angle of rotation of 160° about the rotor longitudinal axis or stator longitudinal axis, respectively, and thus enables a type of cross-sectional detection of the signal. The disposal of the sensor on the rotor is furthermore advantageous, in particular when the sensor is disposed in the region of the external surface of the rotor, because there is the possibility of carrying out by way of the sensor a signal detection of a characteristic value on the stator as well as a characteristic value on the rotor as well as a characteristic value of the conveyed medium during the ongoing operation. This signal detection can take place, in particular, during a revolution of the rotor across 360°. This is made possible in that, in the case of this sensor position on or close to the surface of the rotor, the sensor during the operation of an eccentric screw pump comes in direct contact with the stator, on the one hand, and during the further rotation also comes to be spaced apart from the stator, on the other hand, and as a result comes in contact with the conveyed medium, as a result of which it is in each case possible for the stator and the conveyed medium to be periodically detected. Moreover, the disposal in the rotor per se also makes measuring toward the rotor possible. This can, in particular, be a temperature measurement in which, depending on the angle of rotation of the rotor about the rotor longitudinal axis, the temperature of the stator is measured at specific angles, angular ranges, or across the entire circumference in relation to the stator longitudinal axis, and the temperature of the conveyed medium is moreover measured. Furthermore, for example in that the sensor is embodied with a plurality of probes, the temperature of the rotor can also be detected by the sensor. It is to be fundamentally understood that the sensor can also be embodied as a sensor unit and can detect a plurality of measurement functions for identical or dissimilar physical variables.

[0091] The sensor position shown in FIG. 4a can also be used for piezoelectric or capacitive vibration sensors so as to detect vibrations or accelerations of the rotor at this installation position of the sensor. These here may be sensors measuring in a single axis or in multiple axes. Likewise, eddy current sensors can be used at this position in order to perform a measurement of the spacing or position of the rotor.

[0092] FIG. 4b schematically shows a positioning of the sensor 401 identical to that of FIG. 4a. In this variant of installation however, only the signal line 405 from the sensor to the receiver is hard-wired. In order for the sensor to be supplied with energy, an energy converter 407, which converts temperatures or temperature gradients into electric energy, such as can be carried out by a Pelletier element, for example, is disposed adjacent to the sensor. This energy converter utilizes the fact that, as a result of friction between the rotor and the stator and of the medium flowing therethrough, temperatures which vary in relation to the ambient temperature and consequently temperature gradients arise here which enable a conversion of energy which is sufficient for supplying the sensor with energy.

[0093] FIG. 4c shows a further variant in which the position of the sensor 501 and of the signal line 505 corresponds to the sensor position according to FIG. 4a, and the sensor is supplied with energy by means of an energy converter. The energy converter here is constructed according to the principle of induction, wherein corresponding magnets 508 are disposed as solid magnets or magnetic coils in the inlet housing 50, on the one hand, and a coil 507, in which a current flow is triggered by induction, is situated in the region of the outlet universal joint or at the inlet end of the rotor. The generator/dynamo thus acting in the rotation of the rotor in this instance generates the required electric energy for supplying the sensor by way of a short energy line 506.

[0094] Shown in FIG. 4d is a further variant of the energy supply. In this variant, a piezo converter or an electrodynamic converter 607, which generates electric energy from the vibration which is caused by the eccentric rotating movement of the rotor, is disposed in the rotor, said converter 607 thus supplying the sensor 601 with said electric energy. The signal transmission again takes place by wire over a signal line 605.

[0095] FIGS. 4e and 4f show a variant in which two sensors 701a,b or 801a,b, respectively, are disposed on the rotor at the same angular position in relation to the rotor longitudinal axis B but so as to be axially mutually spaced apart along the rotor longitudinal axis B. The axial spacing of the two sensors 701a, 701b in FIG. 4f here is chosen such that both sensors are disposed in the region of a crest of thread of the thread turn of the rotor, the axial spacing thus corresponding to the pitch of the rotor thread, whereas the axial spacing between the two sensors 801a, 801b in FIG. 4e is chosen such that a sensor is disposed in the region of a crest of thread and the other sensor is disposed in the region of a thread groove, the axial spacing here thus corresponding to half the pitch of the rotor thread. In both variants, the sensors are supplied by way of a common energy line 706, 806, and said sensors emit the respective signals thereof by way of respective separate signal line 705a, 705b or 805a, 805b, respectively.

[0096] FIG. 4g shows a further variant in which two sensors 901a, 901b are disposed on the rotor at the same axial spacing as in FIG. 4e, but in this case not at the same angular position. For the purpose of a phase shift measurement, the sensors are positioned so as to be mutually rotated by 180° about the rotor longitudinal axis.

[0097] FIG. 4h shows a further variant of the disposal of the sensor 1001. In this variant, the sensor is disposed centrally in the rotor longitudinal axis within the rotor and does not extend to an external surface of the rotor. Moreover, the sensor in the axial direction is disposed so as to be approximately centric in the rotor. This disposal is particularly suitable so as to dispose a single-axis or multiple-axes vibration sensor or a gyroscope or a rotation sensor and as a result detect the movement, the speed or the exhilaration of the sensor, the latter by virtue of the eccentric movement enabling a characteristic statement pertaining to the operating state of the eccentric screw pump.

[0098] FIG. 4i shows a variant of the disposal of the sensor, in which the sensor 1101 is likewise disposed so as not to extend to the external surface of the rotor but to remain within the rotor. In contrast to the sensor position illustrated in FIG. 4h, the sensor here is however disposed so as to be radially spaced apart from the rotor longitudinal axis and so as to be situated close to the external surface of the rotor.

[0099] FIG. 4j shows an embodiment in which a wired transmission of data or energy to the sensor 1201 is not required. In a manner corresponding to that of FIG. 4b, an energy converter 1207 here is disposed so as to be adjacent to the sensor. Moreover, a radio transmission module 1209 is also disposed in the rotor so as to be adjacent to the sensor in this embodiment. As a result, the sensor signals can be transmitted to a receiver 1210 which is disposed outside the rotor, in particular outside the stator or the eccentric screw pump.

[0100] FIG. 4k shows a complementary variant in which, besides the sensor 1301, the radio transmission module 1309 is also supplied with energy directly from the energy converter 1307 and said radio transmission module 1309 transmits the signals to an external receiver 1310.

[0101] In both the embodiments according to FIGS. 4j and 4k the sensor is autonomous and disposed on the rotor without the requirement of a wired signal line or a wired energy supply, and therefore is particularly advantageous in terms of assembly and at the same time robust.

[0102] FIGS. 5a-5c show the fundamental principle of generating the measurement signal from a measured parameter and the energy supply required to this end for generating the measurement signal and for transmitting this measurement signal.

[0103] FIG. 5a here shows a sensor 2200 which detects a measured parameter 2201 and by way of a microcontroller 2202 generates and emits a measurement signal 2204. To this end, the sensor is connected directly to a current supply 2203.

[0104] FIG. 5b shows a variant of the principle, in which a sensor 2300 likewise detects a measured parameter 2301 and by way of a microcontroller 2302 emits a measurement signal 2304 that describes this measured parameter. The sensor here is not connected directly to an external energy supply. Provided instead is an energy converter 2305 which converts ambient energy 2303 into electric energy for supplying the sensor 2300 and the microcontroller 2302. The energy converter to this end delivers the generated energy to an energy management and storage module 2306 from which the sensor and the microcontroller are supplied with energy.

[0105] FIG. 5c shows a variant which is based on the above and in which, besides the sensor 2400 which by way of a microcontroller 2402 converts the measured parameter 2401 into a measurement signal 2404, an energy converter 2405 which converts ambient energy 2403 into electric energy and delivers the latter to an energy management and storage module 2406, is also present. The energy management and storage module here supplies the sensor and the microcontroller 2402 with electric energy. Furthermore used is a converter or coupler which operates as a wireless transmission module 2407 and has an antenna 2408 for transmitting the sensor signal 2404 to an outside receiver.

[0106] FIGS. 6a-6d show typical profiles of some characteristic sensor signals which reflect measured parameters detectable on the rotor or the wobble shaft.

[0107] Plotted in FIG. 6a here is the dynamic stiffness 3001 (curve with triangles), the damping work 3002 (curve with rectangles), and the surface temperature 3003 of the stator (curve with dots) across the entire operating period 3010 during which an eccentric screw pump is operated. It can be seen that the surface temperature 3003, proceeding from a running-in phase 3011, in which said surface temperature 3003 is initially low, moves in an acceptable operating window over a long normal operating interval 3012, so as to then exponentially increase in a subsequent fatigue/failure phase 3013. This is typically characterized by exceeding a limit temperature TF 3020. The damping work 3002 which is performed in the rubberized stator, here in terms of the curved profile behaves in a manner similar to the surface temperature 3003 of the stator. The dynamic stiffness 3001 in the running-in phase 3011 is initially high at the very beginning, then remains almost consistent over the normal operating period 3012 so as to drop during the fatigue/failure phase 3013.

[0108] The effects behind these curved profiles depend on various factors, and the curved profile can, therefore, not be explained in terms of a general cause. On the one hand, the initial fit between the rotor and the stator plays a role; an initially tight fit can here lead to an initially high import of frictional energy, the latter then decreasing. On the other hand, the dynamic stiffness of the elastomer (of the stator) also plays a role, for example, said dynamic stiffness describing the ability for propagating vibrations and thus the transport of energy/temperature. Said dynamic stiffness changes during the running-in and starting-up phase 3011 and, when said dynamic stiffness drops, can lead to an increase in temperature which has to be directed through the elastomer.

[0109] FIG. 6b shows the temperature profile of the surface temperature 4020 of the stator over time 4010 during the starting-up behaviour when once ramping up an eccentric screw pump. Illustrated are three typical temperature profiles T1, T2 and T3 which by means of a sensor embedded in the rotor could be detected at three different points in time of the state at a measurement point on the stator. All three temperature profiles show an initially steep increase which then plateaus and settles at a constant temperature level.

[0110] The temperature curve T2 here represents a curve with the comparatively steepest increase whereas the curve T1 has indeed a lesser gradient but climbs to a higher temperature level than T2 by a difference ΔT12. This more steeply increasing temperature curve T2 correlates, for example, with a more heavily decreasing dynamic stiffness or other properties of the elastomer of the stator. The comparison of the stationary temperatures ΔT12 can signal a pumping situation involving a medium with better lubricating properties and a lower temperature, for example. In contrast, a temperature curve T3 having a flatter profile and in relation thereto a settled constant temperature which is lower by ΔT13 can arise in the case of an identical conveyed medium at a lower rotating speed of the pump, for example.

[0111] FIG. 6c and FIG. 6d show in each case the measured values of a position, speed or acceleration 5020 of a position sensor disposed in the external surface of the rotor, or close to the external surface of the rotor, said position sensor potentially being embodied as a rotation sensor or a gyro sensor, for example, in the directions of the three axes X, Y, and Z over time 5010. FIG. 6c here shows a typical curved profile for an eccentric screw pump which is in a normal operating state without any appreciable wear. In contrast, FIG. 6d reflects an operating state of the pump with advanced wear.

[0112] It can be seen here that the positions which in the Z-direction and the Y-direction have a mutual phase shift of 90° have a similar profile in both figures, whereas the position in the X-direction in the normal operating state has an almost stationary value which is subject to certain minor fluctuations only by pulsed pressure influences and axial play in the bearings.

[0113] In contrast, FIG. 6d shows a curved profile which has a significantly larger amplitude in terms of the Z-values and Y-values and moreover displays a significant variance of the X-values from a consistent profile, having a significant albeit irregular vibration of the rotor in the X-direction. All these three characteristic curve profiles indicate increased wear on the eccentric screw pump, this also being evident by radial as well as axial positional variations, accelerations and speeds.

[0114] The operating state of the pump, as a result of the measurement of the trajectory shown in FIGS. 6c and 6d, for example by distance sensors or rotation sensors, can be monitored such that disadvantageous rotor movements, for example, as a result of misalignments or a wobbling movement (FIGS. 6c and 6d) due to play of the rotor (caused by a fading pre-tension of the rotor in the stator) can be identified.