JP2023523059A - Eccentric screw pump status detection - Google Patents

Abstract

An eccentric screw pump, comprising: a pump housing having a pump inlet opening and a pump outlet opening; a stator disposed within the pump housing; a rotor disposed within the stator; a drive motor; a drive unit comprising a drive shaft connecting the drive motor to the rotor for transmission, the rotor in rotary motion about the axis of rotation being guided in the stator and the eccentric screw A state sensor for detecting a state variable of the pump and a state sensor for detecting a state variable in the rotor or the drive shaft may be arranged on the rotor or the drive shaft or may be connected to the rotor by a signal line. or placed away from the rotor or drive shaft by connecting to the drive shaft.

Description

The present invention relates to an eccentric screw pump comprising a pump housing having a pump inlet opening and a pump outlet opening, a stator arranged within the pump housing, and a rotor arranged within the stator. , a drive motor, and a drive shaft connecting the drive motor to a rotor for transmitting torque, the rotor having rotary motion about an axis of rotation being guided in a stator to provide an eccentric screw pump. It has a state sensor for sensing state variables.

Eccentric screw pumps are used to convey a wide variety of media in a wide variety of applications. Eccentric screw pumps operate on the principle of a volumetric displacement pump and for that purpose comprise a rotor which is driven in rotation about a rotor longitudinal axis in a stator. The rotor longitudinal axis then rotates about the stator longitudinal axis, the stator longitudinal axis being spaced from the rotor longitudinal axis and typically extending parallel to the rotor longitudinal axis. there is Thereby, the rotation of the rotor about the longitudinal axis of the stator and the rotation of the rotor about the longitudinal axis of the rotor are complementary eccentric rotations, resulting in a superposition of the rotor in the stator. movement occurs. Since the eccentric screw pump operates at a predetermined rotational speed, which is proportional to the desired conveyed amount, it can be used to systematically convey the predetermined conveyed amount. Eccentric screw pumps are often used in the field of production engineering and are often used to supply liquids containing foreign matter. Especially in production engineering applications, but also in general applications, failure of eccentric screw pumps often leads to long downtime of the entire production line, which is a significant disadvantage for the user.

There are many possible causes for the failure of eccentric screw pumps. Excessive stator wear is a common cause of failure. In many construction modes of eccentric screw pumps, the stator is made as a shell structure by rubber material or other elastomer, and the rotor is made of metal, the wear that occurs between the rotor and stator often causes the stator to Positioned to have a substantive impact. However, the swaying mode of motion caused by eccentric motion also requires a corresponding mounting, and the drive requires a corresponding transmission of torque by a wobble shaft, which is , often embodied by two universal joints. In many modes of construction of eccentric screw pumps, these universal joints are additionally arranged in the inlet region of the stator, as a result of which they are exposed to the friction of the conveying medium, which leads to stresses on these universal joints and the sealing of the universal joints. can leak, which can lead to wear of the fittings and damage to the bearings, and can lead to failure of the eccentric screw pump.

Various solutions have already been proposed to deal with these problems. For eccentric screw pumps with minor eccentricity, the wobble shaft embodiment is embodied as a flexing torsion bar. For example, as a result, two universal joints in the drivetrain can be eliminated, avoiding one cause of wear and failure. However, this configuration mode is not suitable for high throughput pumps. A relatively large eccentricity is advantageous for high throughput pumps, and the construction modes described above are limited to relatively small types of pump construction.

European patent document EP 2 944 819 B1 discloses a mode of construction of an eccentric screw pump that can significantly reduce the repair time for replacing the rotor or stator of the eccentric screw pump. This allows the stator to be externally coupled with the rotor arranged therein without having to disassemble the pipeline connected to the eccentric screw pump for this purpose or perform other disassembly steps. This is achieved by a specific design of the stator flange that allows it to be swiveled into position. Here, the release of the rotor from the wobble shaft required for disassembly of the rotor can be accomplished through a cavity in the rotor itself, so that the inlet chamber for dismantling the flange located in the inlet chamber does not require access to The construction of this maintenance-friendly eccentric screw pump actually offers great advantages when it comes to maintenance. However, in normal production operations, it is further desirable to anticipate maintenance needs in order to be able to better plan such maintenance activities.

To this end, various approaches have been explored to identify operating conditions that require maintenance of eccentric screw pumps.

Monitoring of specific operating parameters of eccentric screw pumps is described in German Patent Document DE 100 63 953 A1, in which pressure transducers, temperature sensors and vibration sensors are located in the area of the joint or mounting or of the rotor or stator. placed in the area. This measurement principle is due to the approach in other types of pump construction. In particular, it is known, for example from Japanese Patent Document JP6015049A or German Patent Document DE19649766A, that monitoring the condition by evaluating temperature or vibration values yields a statement about the wear condition of the pump. However, this approach does not allow for the specific vibration conditions caused by the eccentric motion of the eccentric screw pump to be sufficiently reliable to detect operating conditions indicative of wear versus the normal operating conditions of the eccentric screw pump. It provides the placement of the sensors. With such an approach, this leads to the disadvantage of many different sensor placements to achieve wear condition detection. As a result, the assembly and disassembly of the eccentric screw pump is not only significantly hampered, but also the cost of the eccentric screw pump is increased. Moreover, it has been demonstrated that even with such a complex multiplicity of different sensors, it is not possible to reliably identify wear conditions that actually require maintenance, or only when significant damage has occurred. In particular, it is not possible to identify operating conditions leading to increased wear in a reliable and preventive manner.

From German patent document DE 2005019063 B3 it is known to arrange a vibration sensor outside the eccentric screw pump and evaluate the measurement results of this vibration sensor to draw conclusions regarding specific operating or wear conditions, respectively. there is While this certainly addresses the drawbacks of hindering disassembly and increasing costs due to the large number of sensors, reliable detection of conditions of wear and operating conditions leading to increased wear cannot be achieved by this prior art. .

An updated and more recent approach is known from German patent document DE 10 2018 113 347 A1. In this approach, operating parameters in the form of operating pressure or pump torque are monitored in an eccentric screw pump by sensing pressure at the outlet of the eccentric screw pump. In this operating pressure/torque monitoring, evaluation of the signal by Fourier transform yields statements about specific operating parameters. Theoretically, a sensor assembly at the pump outlet can achieve easier assembly and disassembly compared to previously known solutions. However, the processing of the sensors includes a statement about the operating pressure of the pump, and indirectly deriving a statement about the torque therefrom, by means of a specific evaluation mode and by comparison with calibrated comparison values. There is a drawback that it must be broken. Also, this statement is to a large extent a function of the medium being pumped and influenced by the line network at the pump outlet. Wear conditions, in particular wear conditions that require maintenance or that require maintenance at a foreseeable time in the future, cannot be reliably detected by this detection and measurement evaluation.

Previous approaches specifically target maintenance-required conditions directly. However, according to our concept, it would be advantageous in principle if an eccentric screw pump could be controlled in such a way that particularly wear-causing operating conditions could be prevented proactively. For this purpose, however, it is necessary to detect not only wear states that already require maintenance, but also operating states that lead to increased wear. Also, on the one hand, operating conditions that lead to increased wear can be avoided by modifying the operation of the eccentric screw pump, and on the other hand, the effects of wear can be minimized. According to our concept, this can manifest itself, for example, in the start-up behavior of the pump. This is because a low wear ramp-up of the pump is achieved by a specific increase in rotational speed, which for example can vary depending on the medium conveyed. Furthermore, dry-running conditions can be avoided by identifying in real time that there is no medium to be transported and either stopping the pump or running it at a very low rpm.

Furthermore, from the international patent application WO 2018/130718 A1 filed by the applicant, an eccentric screw pump with a conical design of the rotor and stator is known, whereby an axial can be adjusted so that the gap between the rotor and stator can be adjusted. In this construction mode of the eccentric screw pump, the ramp-up and ramp-down action of the pump can be designed by controlling the axial actuation by the relative axial actuation of the rotor and stator. If a statement about the state of wear and the operational state of the pump is available, it can be circumvented by very rapid control when high-wear operational states are detected. Such a targeted axial adjustment between the rotor and stator, so to speak in real time, can change the type of control action or feedback control loop.

Therefore, there is a need to monitor the condition of the eccentric screw pump, which overcomes the drawbacks of the known detection mode of the operating parameters of the eccentric screw pump, and makes the eccentric screw pump more spontaneous and More accurate control becomes possible.

This object is achieved according to the invention by an eccentric screw pump of the structural mode described above. In the eccentric screw pump, a state sensor for detecting state variables in the rotor or drive shaft is arranged on the rotor or drive shaft or connected to the rotor or drive shaft by a signal line, whereby Disposed away from the rotor or drive shaft.

According to the invention, the state variables are detected directly on the rotor or drive shaft. State variables here should be understood to mean physical variables detected by the sensor installation. This physical variable may be, for example, temperature, fluid pressure, elongation, material stress, alignment with respect to direction of gravity, absolute value and/or direction of velocity, or absolute value and/or direction of exhilaration. This state variable is detected according to the invention by a state sensor, which according to a first alternative is arranged on the rotor or the drive shaft. Therefore, in this first alternative, the status sensor is fixed directly to the rotor or drive shaft. For example, the condition sensor may be fixed to the outer surface of the rotor or drive shaft, embedded within said outer surface, or positioned and fixed in an internal cavity of the rotor or drive shaft. In particular, starting with a cavity in a hollow shaft configured as a rotor or drive shaft, the condition sensor is located on the inner surface of this cavity, or proceeds from this cavity and extends to the outer surface of the rotor or drive shaft, optionally It is arranged in a duct that can also pass through this outer surface.

Alternatively, according to the invention, the state variables can be detected by state sensors connected by signal lines to the rotor or drive shaft and themselves remote from the rotor or drive shaft. In this alternative, the condition sensor is located remotely from the rotor or drive shaft and is connected to the rotor or drive shaft by signal lines. In this alternative, a physically embodied signal line relays physical state variables from sensing points in the rotor or drive shaft to state sensors via the signal line without data transmission, such as by radio waves. is embodied to In this way, the pressure sensed directly at the surface of the rotor or drive shaft, for example by hollow lines such as ducts, hose lines, pipelines, bores, etc., is guided away from the sensing location and to another location. Detected by a state sensor. The signal lines here run from the status sensor to termination located directly on the rotor or drive shaft, as described in the context of the status sensor located directly on the rotor or drive shaft.

By detecting the state variables of the rotor or the drive shaft by means of the respective arrangements of state sensors or signal lines described above, the directly measured variables of the eccentric screw pump are detected, said measured variables being dependent on the operating state of the eccentric screw pump. Allows drawing conclusions about relevant measurements. As a result of this direct detection, on the one hand, physical variables directly correlated with rotor or drive shaft rotation, such as pressure ratio, pressure amplitude or frequency acceleration or variation, or rotation-induced acceleration, etc., can be measured in real time. can be detected directly. By sensing directly at the rotor or drive shaft, respectively, temperature and temperature potential increases can be sensed more in real time at locations where temperature peaks typically occur throughout the eccentric screw pump.

Vibration measurements with sensors arranged on the outer wall of the housing, for example, always require consideration of the transmission and propagation of vibration waves from the vibration source to the sensor when evaluating vibration signals. Material properties and dynamic structural properties, such as the stiffness of the overall structure and thus the natural frequency, play a decisive role here. Furthermore, the damping properties of the conveyed medium and the stator are decisive drawbacks here. Due to the large number of influencing factors, complex structural analysis of the system and modal analysis of the measured signals are often required. Thus, signal components adjusted to account for several influencing factors can be extracted from the entire vibration spectrum, but at the risk of intensive signal processing. This is because either systematic signal errors are introduced into the evaluation signal, or certain status signals can be systematically filtered out of the evaluation signal.

The direct and immediate measurement according to the invention on or in the components involved in the monitoring greatly reduces the above effects and allows simpler methods such as band-pass filters to be applied, so that rotors or drives Shaft evaluation is very easy to implement and achieves high reliability.

By placing the condition sensor on the rotor or drive shaft, the condition sensor rotates in conjunction with the rotor or drive shaft, respectively, and can detect a 360-degree profile to provide a cross-sectional measurement of condition. . The effectiveness of such a measurement is more accurate and far superior to that of a condition sensor fixedly placed on the eccentric screw pump.

The invention is based, inter alia, on the concept that the indirect detection of physical variables and the calculation of critical operating parameters derived therefrom has drawbacks. On the one hand, real-time monitoring by indirect detection, by means of the necessary comparative calculations, the necessary mathematical processes themselves, and the necessary integration time comparisons, allows the identification of operating conditions that lead to increased wear, and corresponding control measures. Avoiding such operating conditions is unreliable and ineffective. On the other hand, the invention is based on the concept of placing status sensors on the rotor or the drive shaft respectively or taking physical measurement variables from the rotor or the drive shaft respectively via signal lines. This allows the maximum value of the state change to be minimized depending on transport parameters such as the temperature and viscosity of the medium being transported, and the detection of the state variable at the position possible that typically detects the most direct state change. enable.

Thus, in accordance with the present invention, state variables with damped and incorrect assumptions detected elsewhere are used to revert to actual changes in state variables at critical locations using inverse calculations. no need to ask. For example, when detecting the temperature or pressure of the rotor or drive shaft, idling can be detected as soon as the idling starts and the resulting wear effects can be immediately avoided by corresponding control. Similarly, excessive stress on the mounting that leads to increased wear of the mounting can be detected by the corresponding characteristic oscillatory behavior of the rotor or drive shaft at the moment the excessive stress first occurs, thus , can also be quickly and effectively avoided by a corresponding reduction in power or rotational speed or other control variables before wear ensues. Finally, the real-time detection of the state variables of the rotor or drive shaft, respectively, is also suitable for actuating the control variables of the conically embodied rotor/stator assembly therefrom. Thereby, the axial adjustment between the rotor and the stator, or the eccentric adjustment, approaches the predetermined operating state of the eccentric screw pump in a targeted manner, or the predetermined operating state of the eccentric screw pump. Profiles can be run in a feedback control loop.

According to a first preferred embodiment, one is provided in which the status sensor is located in the rotor or in the drive shaft or the signal line terminates in the rotor or in the drive shaft. According to this preferred embodiment, state variables are detected at the rotor or the drive shaft, respectively. This makes it possible, on the one hand, to directly detect the state variables of the eccentrically rotating component and, on the other hand, to carry the processing of the state sensors, optionally the necessary sensor lines or energy supply of the sensors, or the signal lines, respectively. to protect against the influence of media that For this purpose, the rotor or drive shaft, respectively, can be configured with an internal cavity, for example as a roller-type rotor or as a hollow shaft. The status sensor or signal line ends, respectively, can be positioned and secured within the internal cavity in this example.

Further preferably, the status sensor is guided and connected to the electronic evaluation unit via a sensor cable, the sensor cable or signal line preferably being routed within a portion of the drive shaft and optionally within a portion of the rotor. be. According to this embodiment, the sensor signal cable, which conducts the sensor signal electrically, or fiber optic or otherwise, can be connected from a status sensor fixed to the drive shaft or rotor to an electronic evaluation unit, or , to signal lines in the case of condition sensors located remotely from the drive shaft or rotor, routed through a portion of the drive shaft, or optionally routed through a portion of the rotor. . Such guidance allows a protected placement of the sensor signal cable or signal line, respectively.

In particular, the sensor cables or signal lines can each extend along the entire driveshaft and along the entire drivetrain to termination or fixed points at status sensors located on the rotor or driveshaft, respectively. , also here partially passing through the drive shaft or the rotor, or both. This allows for total path protection for each sensor cable or signal line so that the sensor signal can be routed from the rotating shaft of the drivetrain to the stationary transmission unit by the corresponding transmission element.

Here, preferably, the drive shaft is a wobble shaft. The wobble shaft is connected to the drive motor at the end facing the drive motor so as to rotate about the drive shaft, and at the end facing the rotor is centered about the rotor axis. and is connected to the rotor for overlapping rotation about a stator axis remote from the rotor axis.

According to this embodiment, the eccentric rotary motion of the rotor is transmitted by the wobble shaft as drive shaft. This wobble shaft is mounted for rotation on the side that connects to the drive motor and to the rotor on the side that connects to the rotor, in which position the eccentric rotary motion of the rotor and the rotor about its longitudinal axis are controlled. perform a rotational motion.

This wobble shaft can in principle be embodied as a bent bar to transmit rotation with small eccentricity. However, it is particularly preferred that the wobble shaft has a central wobble shaft, a first universal joint and a second universal joint, the first universal joint being interposed between the central wobble shaft and the drive motor and a second universal joint. A universal joint is inserted between the central portion of the wobble shaft and the rotor. A wobble shaft that is also suitable for large eccentricities and high torques is provided by the two spaced universal joint design embodiments. A universal joint in this context should be understood to be any joint capable of transmitting rotation through angled routing of the shaft, such as a pin joint, or other mode of construction.

In one embodiment of the design of the wobble shaft with such a universal joint, particularly preferably the sensor cable or signal line is guided inside the first universal joint and/or the second universal joint. Alternatively, sensor cables or signal lines are guided through the first universal joint and optionally through the second universal joint. Alternatively, sensor cables or signal lines are routed around the first universal joint and/or the second universal joint. Thus, inward routing, or through-routing, of the sensor cable and signal lines into or through the first universal joint and/or the second universal joint. Advantageous in protected installations. This can be combined, inter alia, with placing sensor cables or signal lines through the central portion of the wobble shaft. A wobbled shaft with universal joints is often sealed against the medium to be pumped by a seal protection tube that is placed around each universal joint and seals each universal joint. Alternatively, a protective tube extends across both universal joints to seal the central portion of the wobble shaft against the medium to be pumped. In such a case, the sensor cable or signal line can also be installed between this protective tube and the wobble shaft, thereby being likewise protected against the medium to be pumped. . In particular, sensor cables or signal lines can be integrated into such a protective tube or arranged like a double casing between two protective tubes. This also protects the sensor cable against mechanical stress due to the wobble shaft.

Here, it is particularly preferred that the first universal joint is surrounded by a first sealing boot and the second universal joint is surrounded by a second sealing boot. Alternatively, the first universal joint and the second universal joint and the wobble shaft are surrounded by a sealing sleeve and the pressure sensor is located in the first and/or second sealing boot or sealing sleeve. or by guiding the pressure line into the first and/or second sealing boot or sealing sleeve, and by fluidly connecting the pressure sensor to the pressure line and in the first and/or second sealing boot or sealing sleeve. Detect pressure. Alternatively, for signal transmission a pressure sensor is connected to the evaluation unit, the pressure sensor being adapted to detect the pressure in the first and/or second sealing boot or sealing sleeve. The pressure sensor preferably detects the pressure of the pressurized medium. The pressurized medium is supplied by or by pressure lines guided in the first and/or second sealing boot or sealing sleeve.

According to embodiments, the pressure sensors are arranged in one of the sealing boots or the sealing sleeves, or one pressure sensor is arranged in each sealing boot. and guided in a first or second sealing boot around the first universal joint or the second universal joint, respectively, or guided in a common sealing sleeve of the first universal joint or the second universal joint; A pressure line that detects the pressure in the sealing boot or sealing sleeve, respectively, is used as a signal line. In particular, a first pressure sensor arranged in the first sealing boot or connected to a pressure line leading into the first sealing boot and a pressure sensor arranged in the second sealing boot or connected to the first sealing boot. A second pressure sensor connected to the pressure line leading to the two sealing boots can also be provided here. A pressure sensing structure within the sealing boot or sealing sleeve can indicate leakage of the sealing boot/sealing sleeve and reliably and directly detect a decrease or increase in pressure within the sealing boot. Such leakage causes rapid access of the ultimately pumped medium to the universal joint, an event that quickly leads to high wear. Detection of this leak is therefore important to avoid such undesirably high wear. In this case, the invention makes it possible to seal or replace the sealing sleeve before such wear occurs. Such wear then leads to the need for complex repairs involving replacement of one or both universal joints and optionally additional mounting elements. Here, it is particularly advantageous to supply the pressurized medium via a pressure line to the sealing boot or the sealing sleeve, respectively. This can also be done via the signal line as long as the pressure line is provided as the signal line. This makes it possible to build and maintain pressure within the sealing boot. On the one hand, this creates a space between the sealing boot or sealing sleeve, respectively, and the universal joint, which makes it possible to avoid mechanical damage to the sealing boot or sealing sleeve, respectively, by the universal joint. On the other hand, a defined pressure occurs in the sealing boot or the sealing sleeve, respectively, by means of which a pressure loss can be reliably established and distinguished from pressure effects generated by the conveyed medium itself.

According to a further embodiment, a state sensor for signal transmission is connected to the electronic evaluation unit, which uses the data of the state sensor to determine the variance of the actual state detected by the state sensor with respect to a predetermined desired state. configured to determine The determined variance is then compared to a predetermined allowable variance and an alarm signal is issued if the determined variance exceeds the allowable variance.

Specifically, the electronic evaluation unit is configured to receive the state sensor signal as the actual state, compares the state sensor signal with the normal state sensor signal stored as the target state, and calculates the determined variance as , calculated as the difference between the state sensor signal and the normal state sensor signal, and using the predetermined allowable variance value as the predetermined allowable variance, a value alert signal is issued as the alert signal. According to these refinements, a condition sensor signal indicative of an unfavorable operating condition is detected by the condition sensor, and operating conditions that cause or may increase wear are identified by target data and actual data. can be identified based on a comparison with The target data here are in electronically stored form, e.g. as data values, data value profiles, algorithmic descriptions of data value profiles or as a comparison table with multiple target values for different operating states of the eccentric screw pump. exist. The target data can be pre-determined and pre-stored so that it can be included in the factory eccentric screw pump. As it were, the target data contain characteristic values which are characteristic and constant in the configuration mode of the eccentric screw pump.

The target data can be defined by pump-specific configuration characteristics, such as constant state values caused by eccentricity, stress values defined by the drivetrain, and the like. However, target data can also be determined as a reference or calibration value when pumping a particular medium and then stored. This reference or calibration value can be determined by the user when pumping a particular medium for the first time or when commissioning the pump for the first time in a particular installation situation, for example for comparison in subsequent monitoring. can be used for This allows immediate identification of critical changes in subsequent actual value measurements compared to the original reference or calibration values. In principle, deviations of the actual data from the reference data are issued as alarms. However, defining a tolerance range is often practiced. Within the tolerance range, the critical operating conditions of the eccentric screw pump are not determined, although the actual value may differ from the nominal value.

According to a further preferred embodiment, the electronic evaluation unit is arranged to receive the state sensor signals, determines the state change value as the actual state from the at least two temporally successive state sensor signals, the state change value is compared with the normal state change value stored as the target state, the determined variance is calculated as the difference between the state change value and the normal state change value, and the predetermined allowable change variance value is calculated as the predetermined allowable Use as a variance and issue a change alert signal as the alert signal.

Further preferably, the electronic evaluation unit is arranged to receive the state sensor signals and determines from the at least three temporally successive state sensor signals a state change rate as the actual state and a state change rate as the target state. Comparing with the stored normal state change speed, calculating the determined variance as the difference between the state change speed and the normal state change speed, using the predetermined allowable speed change as the predetermined allowable variance, and alarming the change speed A signal is emitted as an alarm signal.

According to these refinements, a state change signal is determined which is characterized by two temporally successive changes in actual value. This state change signal can be understood to be the first time derivative of the state signal and provides a measure of the critical operating state that has already occurred or is in progress and is superior to the absolute value of the state signal. . Similarly, the state change rate can be determined by the time series of the state sensor signal and should be understood to be the second time derivative of the state signal. By calculating and utilizing these state change values or state change rates, the velocity on the one hand and the acceleration at which the state signal changes on the other hand are determined. To detect critical operating conditions of eccentric screw pumps that have already occurred or are in progress, these two values are more suitable for many physical variables detected in the rotor or drive shaft than the condition signal alone. ing. If only status signals are detected, in many cases only one critical limit can be defined. However, in order to allow normal operation without interruption or alarms, this limit should be specified to actually approach the critical limit. In contrast, when detecting the rate of change of the state signal or the rate of change of the rate of change, whether the eccentric screw pump is moving towards the critical operating state is still within an acceptable range for the absolute value of the state signal. can also be specified. For example, a large increase in pressure in an eccentric screw pump, or a very rapid change in pressure increase or decrease, can indicate a wear condition on the pressure side of the pump or a wear condition on the suction side of the pump, and these can be determined at an early stage, thereby establishing the operation of the eccentric screw pump. Similarly, a large increase in temperature, or a large rate of change in temperature increase, and an acceleration in temperature increase can already signal dry running, even if the absolute temperature has not yet reached the critical state value. Again, the real-time response of the control of the eccentric screw pump as a result of direct condition detection at the rotor or drive shaft, and the first or second time derivative as a result of monitoring conditions. Resulting, allowing determination of the difference, and real-time response can prevent damage and wear before they occur.

It is further preferred here overall that the electronic evaluation unit is arranged to compare a plurality of temporally consecutive actual states with a plurality of temporally consecutive target states, wherein as the determined variance: It is calculated by comparing the variance feature values, and the predetermined allowable variance feature value is used as the predetermined allowable variance. According to this embodiment, a predetermined variance for changes in the determined change of the state variable or rate of change of the state variable is utilized. This allows operation within tolerances that are judged to be non-critical, and triggers corresponding alarms when these tolerances are exceeded.

More preferably, the eccentric screw pump has a rotor with a conical envelope and a conically tapered stator interior. The rotor and stator are axially adjustable with respect to each other by an axial drive. The electronic evaluation unit for signal transmission is connected to the axial drive and is adapted to actuate the drive, thereby effecting the axial adjustment between the rotor and the stator, and A plurality of time-sequential status sensor status sensor signals are sensed during the axial alignment operation. According to this embodiment, the conically tapered rotor and stator provide an axial alignment movement between the rotor and stator, thereby Allows adjustment of the radial gap between. To this end, the stator can be configured to be stationary and the rotor can be axially adjustable. The axial adjustment device can in particular provide axial adjustment of the rotor during on-going operation, for example the rotor can be geared with a wobble shaft and the drive motor can be axially adjusted. For this purpose, for example, actuatable actuators can be used, which can preferably be set to predetermined axial positions by way of path sensors. The drive motor or other part of the drive train may also be configured to be axially stationary and connected to the rotor by a torque-transmitting axial thrust connection. Axial adjustment motion of the rotor typically affects the state signal and can be used to achieve changes in the state signal. According to the invention, for this purpose, at least one status signal, preferably a plurality of temporally successive status signals, is detected during the adjustment operation. Axial adjustment actions can be performed as a function of the status signal. This can therefore be done by controlling the axial adjustment or by a feedback control loop. That is, the status signal acts as an input or command variable, and the axial adjustment motion acts as an output or control variable. Axial adjustment between the rotor and stator can spontaneously modify the operating conditions of the eccentric screw pump. Said axial adjustment can be used to optimize the start-up procedure of the pump, e.g. to achieve a power saving ramp-up at a larger gap and then, when the desired rotational speed is reached, Or reduce the gap during ramp-up. In addition, by monitoring state signals such as drive power, torque or temperature, axial adjustments can be made until the ideal gap between the rotor and stator is obtained in terms of pump efficiency and wear. It can be performed.

More preferably, the condition sensor is located on the drive shaft or rotor and is further connected to the condition sensor data transmission module to wirelessly transmit the condition data to a data receiver external to the eccentric screw pump. The state sensor and the state sensor data transmission module for receiving electrical energy are connected to an energy converter, which is arranged on the rotor or the drive shaft and converts the kinetic or thermal energy acting on the energy converter into electricity. configured to convert to energy. According to this embodiment, the state sensor is arranged on the rotor or drive shaft as an autonomous module to wirelessly transmit state data to a receiver located remotely from said state sensor. Here, the energy required to detect and transmit state data is provided by an energy converter. The energy converter can likewise be arranged on the rotor or drive shaft and directly connected to the state sensor for transmitting energy or embodied as a module in common with said state sensor. For example, the energy converter may be embodied such that the energy converter produces electrical energy from acceleration or vibrations resulting from induction from rotary motion. Other types of converters can also be used, for example thermal converters that produce electrical energy from the temperature of the medium to be pumped.

the energy converter
a converter based on the principle of electromagnetic induction, said converter converting the relative rotary motion of the rotor or wobble shaft with respect to the pump housing into electrical energy;
Converters based on the principle of electromagnetic induction, reciprocating rotor or wobble shaft resulting from rotation of the rotor or wobble shaft about the rotor axis and from rotation of the rotor about the eccentric axis said converter for converting acceleration into electrical energy;
Converters based on the thermoelectric principle for converting temperature gradients into electrical energy, in particular temperature gradients between the conveyed medium and pump components such as rotors, wobble shafts or stators. the converter located in the exposed area;
It is particularly preferred to be selected from

More preferably, two state sensors arranged at two positions spaced from each other are arranged on the rotor, the two positions having a phase shift of the measured state variable. The phase shift is preferably such that the axial separation of the state sensors is greater or less than an integer multiple of the rotor pitch, or the angular separation of the two state sensors spans 360 degrees over the rotor pitch course. is not equal to an integer multiple of the value divided by the number of courses). Simultaneous phase shift measurement of two state variables is achieved by this embodiment. Phase shift here is understood to mean detection of two state variables within a periodic profile. Two state variables within a periodic profile occur at two points in the periodic profile, the two points being separated from each other by not exactly an integer multiple of the wavelength of the periodic profile. The detection of these two state variables by the two state sensors of the three-turn eccentric screw rotor can be done in various ways of arrangement. For example, the two state sensors are not actually axially spaced apart from each other and are therefore located in the cross-sectional plane of the rotor, but in this cross-sectional plane 360°/n of each other (where n is , which is the number of thread courses of the rotor), the phase shift can be achieved. Therefore, phase shift measurements for a three-turn eccentric screw rotor can be performed when the state sensors are not equal to 120° or 240° and are offset from each other by an angle of, for example, 90° or 180°. can. For a two-turn eccentric screw rotor, phase shift measurements require an angular offset not equal to 180°. For a four-turn eccentric screw rotor, the angular offsets should be unequal to 90°, 180°, and 270°. Here, for reasons of principle, it must be taken into account that the number of stator thread courses in the case of eccentric screw pumps always exceeds the number of rotor thread courses by one.

However, a phase shift measurement can also be achieved if the angular offset of the state sensor corresponds to a value of 360 degrees/n, i.e. in this case the state sensor is not equal to a multiple of the rotor thread pitch. By axially separating by a distance, a phase shift measurement can be achieved. Pitch here is understood to be the axial spacing between two adjacent threads, in the case of a single-turn thread the pitch corresponds to the lead, in the case of a multi-turn thread the pitch corresponds to the lead/ Corresponds to the value of the number of screw revolutions (n). Specifically, the phase shift can be set as follows. That is, a phase shift of half a wavelength is achieved by separating the state sensors from each other by an axial distance corresponding to half the pitch.

Measurements using phase shifts can provide particularly advantageous monitoring of certain indicators of wear. In this way, by subtracting the sensor signals of the two state sensors, it is possible to obtain a measured variable that is adjusted for the effects occurring in the case of one phase only, which is local in the range of angles. It can show the result of wear occurring in Additionally, by comparing the acquired sensor signals offset in time by the phase shift, a relative statement of state change can be obtained.

Alternatively or additionally, in certain applications it is advantageous for the rotor to have two state sensors arranged in two phase-equal positions spaced apart from each other. Equal phase is preferably achieved by the axial spacing of the condition sensors corresponding to a multiple of the rotor pitch. Alternatively, it can be achieved by making the angular separation between the two status sensors an integer multiple of 360 degrees divided by the number of revolutions of the screw. What is achieved by this embodiment is simultaneous phase-synchronous measurement of two state variables. In this measurement mode, it is possible to compare two state values detected simultaneously at different positions, so that direct conclusions can be drawn about locally occurring operating state changes.

Particularly preferably, more than two state sensors are provided, of which two state sensors are arranged with a phase shift relative to each other and two state sensors are arranged with an equal phase. This allows us to combine the above advantages to get a comprehensive statement about the operating conditions.

More preferably, the state sensor is a temperature sensor, pressure sensor, vibration sensor or acceleration sensor.

Here, evaluation by comparison with previously stored and/or calibrated master curves can provide information about temperature equilibrium being achieved. A detailed analysis of the curve profile, taking into account slope and curvature, allows further evaluation. Thus, the relaxation time constant correlates with, for example, the dynamic properties of the stator's elastomer jacket. A comparison of area integrals indicates damping performance during the running-in phase.

Theoretically, the pressure difference can be used to calculate the volumetric flow rate. For example, it can be determined by measurements from two or more pressure sensors axially spaced along the rotor axis.

For example, by measuring the vibrations generated in the rotor, performed by acceleration sensors or vibration sensors, it is possible to monitor the natural frequency of the rotor/stator system under continuous excitation in the pumping operation. When there is a significant change in the signal ratio, for example, the initiation or propagation of cracks or deformations in the stator can be identified, on the basis of which conclusions about the material and structural properties of the rotor can be drawn. In addition, it is possible to detect impacts caused by relatively large foreign objects, such as stones or screws, that have entered the medium being transported. When such an operating condition is detected, the user of the pump can be warned of damage from this foreign object. The pumping process can then be verified by the user to prevent damage to the pump. Alternatively, control measures derived directly from the status sensor signal, such as an emergency stop or a reduction in rotational speed of the pump, can be implemented.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

1 shows a longitudinal section through an eccentric screw pump according to the invention; FIG. 1 shows a longitudinal section of part of a first embodiment of an eccentric screw pump according to the invention; FIG. Figure 3 shows a second embodiment of the invention of the eccentric screw pump according to Figure 2; FIG. 12 shows a partial longitudinal sectional view of a third embodiment of the invention; Figure 4b shows a fourth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a fifth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a sixth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a seventh embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows an eighth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a ninth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a tenth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows an eleventh embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a twelfth embodiment of the invention of the eccentric screw pump according to Figure 4a; Figure 4b shows a thirteenth embodiment of the invention of the eccentric screw pump according to Figure 4a; Fig. 4 is a schematic diagram showing the measurement procedure performed on the wobble shaft or rotor respectively according to the first embodiment; Fig. 4 is a schematic diagram showing the measurement procedure performed on the wobble shaft or rotor, respectively, according to the second embodiment; Fig. 10 is a schematic diagram showing the measurement procedure performed on the wobble shaft or rotor, respectively, according to the third embodiment; FIG. 3 is a schematic diagram showing profiles of three characteristic measurements recorded on the wobble shaft or rotor over the operating time of an eccentric screw pump; FIG. 3 shows a typical schematic profile of three temperatures recorded in the rotor over time; FIG. 4 shows a typical schematic profile of motion over time in three directions of a sensor fixed to a rotor under normal operating conditions; FIG. 3 shows a typical schematic profile of motion over time in three directions of a sensor fixed to the rotor under operating conditions of a pump with advanced wear;

FIG. 1 shows a typical construction of an eccentric screw pump. The pump comprises a stator 10 having a cavity in the form of a spiral screw path having two turns extending along the longitudinal axis A of the stator. The stator 10 typically comprises a metal pipe 11 or other stable enclosure surrounding an elastomeric casing 12 defining an inner screw-shaped cavity. The rotor 20 extends along a rotor longitudinal axis B which extends parallel to and offset from the stator longitudinal axis A by a so-called "eccentricity" and is positioned within a cavity of the stator. Eccentric screw pumps can be constructed with rotors and stators of various speeds. As a rule, the rotor speed is always one turn higher than the stator speed in order to satisfy the functioning principle.

The stator interior and rotor can be tapered in the axial, or pumping direction (not shown). Thereby, the ends within the rotor and stator facing the inlet opening 1 have a larger cross-sectional area than the ends facing the outlet opening 2 . In such tapered rotors and stators (which typically each have a conical envelope or a conically tapered interior), the rotor and stator are axially mutually (axial movement Ax). Preferably, this axial actuation is possible during the rotational movement Ro of the rotor. As a result, play in the stator due to wear or insufficient pre-tensioning of the rotor, respectively, can be compensated. On the one hand, the rotor is pushed further into the stator. Additionally, the start-up behavior of the pump can be optimized by axial adjustment. For example, axial adjustment is performed by state variables as a function of pumping behavior. For example, it can be adjusted according to different viscosities of the medium to be transported.

Rotor 20 is arranged to rotate about rotor longitudinal axis B of rotor 20 by wobble shaft 30 . The wobble shaft 30 is inserted between the rotor and the drive input shaft, the drive input shaft is driven by the drive motor 40 through the belt drive 41, and the wobble shaft 30 rotates the rotary motion of the drive motor 40. transmit to child 20; Wobble shaft 30 extends from a drive input end 30a mounted for rotation within inlet housing 50 to a drive output end 30b connected to the rotor. Wobble shaft 30 undergoes a compound motion at drive output end 30b. The compound motion includes rotation about the rotor longitudinal axis B and rotation of the rotor longitudinal axis B about the stator longitudinal axis A. At this drive output the wobble shaft can be guided by an eccentric mounting with two rotary bearings with eccentrically offset axes. Alternatively, the wobble shaft can be unguided and the motion of the drive output end of the wobble shaft can be defined by the guidance of the rotor within the stator.

The wobble shaft 30 has an input universal joint 31 at its drive input end 30a and an output universal joint 32 at its drive output end. A shaft portion 33 connecting 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 is connected to the output shaft of the drive motor 40 via a belt drive. An output universal joint 32 is connected to the rotor.

The entire wobble shaft 30 is arranged in the inlet housing 50 and is surrounded by the medium to be pumped, which flows into the inlet housing 50 through the inlet opening 51 . This represents the suction side of the pump. The wobble shaft is then completely surrounded by a protective casing 36. A protective casing 36 extends over the input universal joint 31 , the shaft portion 33 and the output universal joint 32 .

Rotor 20 and stator 10 extend from an inlet end 10 a secured to the inlet housing to an outlet end 20 a secured to the outlet housing 60 . An outlet opening 61 is arranged in the outlet housing 60, through which the medium conveyed from the pump flows, the outlet opening 61 representing the pressure side of the pump.

FIG. 2 is a cross-sectional view showing a wobble shaft. The illustrated wobble shaft is shown with a drive input shaft and rotor attached to it. In this embodiment, the sensor 101 is inserted in a rotor bore 102, which extends radially with respect to the rotor longitudinal axis B. FIG. A sensor may be, for example, a temperature sensor, an acceleration sensor, or a pressure sensor. The rotor 20 further has a longitudinal bore 21 extending along the rotor longitudinal axis B, ie the rotor 20 and the bore 21 are coaxial.

In the embodiment according to FIG. 2 the sensors 101 are connected by sensor signal lines 110 . The sensor signal line 110 is guided through the rotor longitudinal bore 21 and therefrom into the flange longitudinal bore 34 of the connecting flange of the output universal joint 31 . Said flange longitudinal bore 34 extends coaxially with longitudinal bore 21 . From this flange longitudinal bore 34 the sensor signal line 103 extends through a bore in the connecting flange of the output universal joint 31 to a location outside the universal joint 31 . Said bore extends radially to the longitudinal axis B of the rotor. The signal line is then guided 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 the input end, the signal line is guided in the same way as at the output end, first through the radial bore of the shaft portion proximal connection flange of the input universal joint and into the axial bore of the drive input shaft proximal connection flange of the universal joint. It is guided from there into a coaxial longitudinal bore in the drive input shaft. The sensor signal line can then be guided to the sensor signal rotary transmission unit. The sensor signal rotary transmission unit can, for example, be embodied in the form of a plurality of collector rings or the like, which route the sensor signals from the rotating part of the eccentric screw pump to the outside to the fixed part of the eccentric screw pump. be able to.

FIG. 3 shows a modification of routing of signal lines. This figure shows basically the same structure as FIG. However, the signal lines in this variant are guided only through the axial longitudinal bores in the connecting flange of the output universal joint, the shaft portion and the connecting flange of the input universal joint, and in the longitudinal bore of the drive shaft. It differs in that it re-enters.

In this embodiment, the signal lines also run through corresponding lateral bores in the pins of the two universal joints. Here, the ducts through which the signal wires pass should be of a size corresponding to their dimensions so that they are not sheared by the signal wires and are not damaged by the wobbly movements that occur during operation and during universal joint bending conditions. is understood to be embodied in

The drive input shaft proximal to the input universal joint shown in FIGS. 2 and 3 may be secured with a central pin. The central pin passes partially or completely through the drive input shaft and is secured to the universal joint so as to axially pull the conical interference fit between the drive input shaft and the universal joint. do. A further difference is in the signal lines of the drive input shaft. The signal lines in the drive input shaft of the embodiment according to FIG. be. In the embodiment according to FIG. 3, a hollow pin is provided, which is arranged in the drive input shaft embodied as a hollow shaft, and the signal line is guided in the inner cavity of this hollow pin.

Different variants of the arrangement of the sensors on the rotor are shown in Figures 4a to 4k. It should be understood in principle that the sensors shown in these figures can be pressure sensors, temperature sensors, acceleration sensors, vibration sensors or other sensors. Furthermore, it should also be understood that the sensor placement variations shown in Figures 4a to 4k can be combined with each other. Specifically, these variations allow the same type of sensor to be placed in different locations. Alternatively, these variations allow the same type of sensor to be used in different locations. Alternatively, multiple sensors of different types can be placed at one location shown in these variations. The principles of signal transmission and energy supply of the sensors shown in these variants according to FIGS. 4a to 4k can likewise be combined with one another.

Figure 4a shows the placement of sensors 301 within the rotor, which are inserted into the outer surface of the rotor. With this arrangement of the sensors, if the sensors are intended to transmit sensor signals by means of signal lines 305, and optionally parallel to said signal lines 305, as described above with reference to FIGS. If it is intended to be energized by the energy line 306 running in the rotor, it can be achieved by corresponding bores extending radially in the rotor and axially extending in the rotor. can be done.

Generally, it is advantageous to place the sensors on the outer surface of the rotor. Because this position, on the one hand, allows the detection of the rotation signal and thus over a rotation angle of 160 degrees about the rotor longitudinal axis or the stator longitudinal axis respectively, which provides a kind of cross-section This is because it becomes possible to effectively detect signals. Arranging the sensors on the rotor has further advantages, especially if the sensors are arranged in the region of the outer surface of the rotor. This is because, during ongoing operation, signal detection of stator, rotor and conveyed medium characteristics may be performed via the sensors. This signal detection can be done especially when the rotor is rotating 360 degrees. The reason why this is possible is considered as follows. Thus, when the sensor is located on or near the surface of the rotor, during operation of the eccentric screw pump, the sensor comes into direct contact with the stator on the one hand, On the other hand, further rotation causes it to move away from the stator and come into contact with the transported media. This makes it possible in any case to periodically detect the stator and the conveyed medium. It is also possible to measure the rotor as it is located on the rotor itself. This allows, in particular, temperature measurement. In temperature measurement, depending on the angle of rotation of the rotor about the longitudinal axis of the rotor, the temperature of the stator is measured over a given angle, range of angles, or over the circumference with respect to the longitudinal axis of the stator. Also, the temperature of the transported medium is measured. Furthermore, the temperature of the rotor can also be detected by the sensor, for example if the sensor is embodied with a plurality of probes. It should be understood that in principle the sensor can also be implemented as a sensor unit and can detect multiple measurement functions of the same or different physical variables.

Piezoelectric sensors or capacitive vibration sensors can also be arranged at the positions of the sensors shown in FIG. These sensors may be sensors that measure on a single axis or multiple axes. Similarly, an eddy current sensor can be placed at that location to perform a rotor spacing or position measurement.

FIG. 4b schematically shows the positioning of the same sensor 401 as in FIG. 4a. However, in this alternative arrangement, only the signal line 405 from the sensor to the receiver is hard-wired. An energy converter 407, which converts temperature or temperature gradients into electrical energy to supply energy to the sensor, can be implemented, for example, by a Peltier element. A Peltier element can, for example, be placed adjacent to the sensor. This energy converter takes advantage of the fact that the friction between the rotor and stator and the medium flowing there causes a temperature change with respect to the ambient temperature and a temperature gradient there. The resulting temperature change or temperature gradient with respect to the ambient temperature allows the conversion of sufficient energy to power the sensor.

FIG. 4c shows a further variation in the position of the sensor 501 and signal line 505 with respect to the sensor position according to FIG. 4a. The sensor is supplied with energy by an energy converter. The energy converter here is constructed according to the principle of induction. On the one hand, the corresponding magnets 508 are arranged as solid magnets or magnetic coils in the inlet housing 50, and on the other hand, the coils 507 are located in the area of the outlet universal joint or the inlet end of the rotor, and in the coils 507, Induction triggers current flow. Coil 507, in which current flow is induced by induction, is located in the region of the exit universal joint or at the entrance end of the rotor. In this case, a generator/dynamo operating in the rotation of the rotor produces the necessary electrical energy to supply the sensor via a short energy line 506 .

FIG. 4d shows a further variant of energy supply. In this variant, a piezoconverter or electrodynamic converter 607 is arranged in the rotor to generate electrical energy from the vibrations caused by the eccentric rotary motion of the rotor. Converter 607 then supplies electrical energy to sensor 601 . Transmission of signals is also wired via signal line 605 .

Figures 4e and 4f show that two sensors 701a, 701b or 801a, 801b, respectively, are placed on the rotor at the same angular position with respect to the rotor longitudinal axis B, but at the rotor longitudinal axis B 4 shows variants arranged axially apart from each other along. The axial spacing of the two sensors 801a, 801b in FIG. 4f is such that both sensors are located within one thread area of the rotor thread rotation and the axial spacing corresponds to the pitch of the rotor thread. selected for On the other hand, the axial spacing of the two sensors 701a, 701b in FIG. is selected to correspond to half the pitch of In both variants the two sensors are powered by a common energy line 706, 806 and the two sensors emit signals by separate signal lines 705a, 705b or 805a, 805b respectively.

FIG. 4g shows a further variant in which the two sensors 901a, 901b are arranged on the rotor with a similar axial spacing as in FIG. 4e, but in this case not at the same angular position. For the purpose of phase shift measurement, the two sensors are arranged such that they are rotated 180 degrees relative to each other about the rotor longitudinal axis.

FIG. 4h shows a further variant of the placement of the sensor 1001. FIG. In this variant, the sensor is centrally located within the rotor at the rotor longitudinal axis and does not extend to the outer surface of the rotor. In addition, the axial sensor is arranged substantially at the center of the rotor. This arrangement is particularly suitable for arranging single or multi-axis vibration sensors, or gyroscopes, or rotation sensors. This detects motion, velocity, or exhilaration of the sensor. The latter is due to the eccentric movement that allows a characteristic statement about the operating state of the eccentric screw pump.

Figure 4i shows a variant of the sensor arrangement, in which the sensors 1101 are likewise arranged so that they do not extend to the outer surface of the rotor, but remain within the rotor. However, in contrast to the location of the sensors shown in Figure 4h, the sensors in this variant are positioned radially away from the rotor longitudinal axis and located near the outer surface of the rotor.

FIG. 4j shows an embodiment in which wired transmission of data or energy to sensor 1201 is not required. The energy converter 1207 is positioned adjacent to the sensor, corresponding to the embodiment shown in FIG. 4b. Additionally, in this embodiment, a wireless transmission module 1209 is also positioned within the rotor adjacent to the sensor. This allows the sensor signal to be transmitted to a receiver 1210 arranged outside the rotor, in particular outside the stator or the eccentric screw pump.

FIG. 4k shows a complementary variant. In this variant, in addition to the sensor 1301 , the wireless transmission module 1309 is also directly energized by the energy converter 1307 , and the wireless transmission module 1309 transmits signals to the external receiver 1310 .

In both the embodiments according to Figures 4j and 4k, the sensors are autonomous and are placed on the rotor without the need for wired signal lines or wired energy supplies. It is therefore particularly advantageous and robust in terms of assembly.

Figures 5a to 5c show the basic principle of generating a measurement signal from a measurement parameter and the energy supply required for generating the measurement signal and for transmitting this measurement signal.

FIG. 5a shows a sensor 2200 that detects a measured parameter 2201 and generates and emits a measurement signal 2204 via a microcontroller 2201. FIG. For this purpose the sensor is directly connected to the current source 2203 .

FIG. 5b shows a variant of the above basic principle. In this variant, a sensor 2300 likewise detects a measured parameter 2301 and, via a microcontroller 2302, emits a measured signal 2304 representative of this measured parameter. The sensors here are not directly connected to an external energy supply. Instead an energy converter 2305 is provided, which converts the ambient energy 2303 into electrical energy for feeding the sensor 2300 and microcontroller 2302 . For this purpose, the energy converter delivers the generated energy to the energy management and storage module 2306, from which the energy to the sensors and microcontrollers is supplied.

FIG. 5c shows a variant based on the above basic principle. In this variant, in addition to the sensor 2400 converting the measured parameter 2401 into a measured signal 2404 via the microcontroller 2402, there is also an energy sensor that converts the ambient energy 2403 into electrical energy and delivers the electrical energy to the energy management and storage module 2406. A converter 2405 is also shown. The energy management and storage module then supplies electrical energy to the sensors and microcontroller 2402 . Additionally, a converter or coupler is utilized that acts as a wireless transmission module 2407 and has an antenna 2408 for transmitting the sensor signal 2404 to an external receiver.

Figures 6a to 6d show typical profiles of some characteristic sensor signals reflecting the measured parameters detectable at the rotor or wobble shaft.

Figure 6a shows dynamic stiffness 3001 (curves with data in triangles), braking action 3002 (curves with data in rectangles) and stator surface temperature 3003 (dots is a graph showing a curve showing data at . that the surface temperature 3003 starts with an initially low run-in phase 3011, moves within an acceptable operating window over a long normal operating period 3012, and then increases exponentially during the fatigue/failure phase 3013; I understand. This is usually characterized by exceeding the limit temperature TF3020. The braking action 3002 exerted on the rubberized stator has a similar behavior to the stator surface temperature 3003 in curvilinear profile as shown. The dynamic stiffness 3001 initially has a high value during the break-in phase 3011 , then remains fairly consistent during normal operation and tends to drop off during the fatigue/failure phase 3013 .

Due to the variety of factors that influence these curve profiles, they cannot be explained in terms of general causes. On the one hand, the initial fit between the rotor and stator is important, and an initial tight fit tends to result in an initially high import of frictional energy and then a decreasing trend. On the other hand, the dynamic stiffness of the elastomer (of the stator) also plays an important role. For example, dynamic stiffness describes the ability to propagate vibrations and the ability to transfer energy/temperature. The dynamic stiffness changes during the break-in and start-up phases 3011, and when the dynamic stiffness is reduced, the transmission capability of the elastomer may be reduced, resulting in increased temperatures.

FIG. 6b shows the temperature profile of the stator surface temperature 4020 against time 4010 during the start-up behavior of the eccentric screw pump once started. Three typical temperature profiles T1, T2, and T3 are shown, detected at three different points in this condition at the measurement points on the stator by sensors embedded in the rotor. be. All three temperature profiles show an initial sharp rise, then leveling off and settling to a constant temperature level.

Here, the temperature curve T2 shows a relatively steep rising curve, while the temperature curve T1 has a relatively small slope but reaches a temperature level higher than T2 by a difference ΔT12. This more steeply rising temperature curve T2 correlates with, for example, a significant reduction in dynamic stiffness or other properties of the stator elastomer. A steady-state temperature value comparison ΔT12 can, for example, inform the pumping situation for a medium with better lubricity and lower temperature. In contrast, the temperature curve T3 has a flatter profile and, associated, a steady-state temperature value that is ΔT13 lower. This can occur, for example, with the same transport medium at a lower rotational speed of the pump.

Figures 6c and 6d show position, velocity, or acceleration 5020 measurements, respectively, of position sensors located at or near the outer surface of the rotor. The position sensor may, for example, be embodied as a rotational or gyroscopic sensor in three axes X, Y, and Z over time 5010 . Figure 6c shows a typical curvilinear profile of an eccentric screw pump, when in normal operating condition with little wear. In contrast, Figure 6d represents the operating state of the pump as wear progresses.

As shown, locations with mutual phase shifts of 90 degrees in the Z and Y directions have similar profiles in both figures. On the other hand, in normal operating conditions, the position in the X direction has a substantially constant value. It has a predetermined small variation due only to the effect of the pulse pressure and the axial play of the bearing.

In contrast, FIG. 6d shows a curve profile with significantly higher amplitudes for Z and Y values. In addition, the X-values show a significant variance from the steady-state profile, highlighting the random oscillations of the rotor in the X-direction. All three of these characteristic curve profiles show increased wear of the eccentric screw pump. This is also manifested by radial and axial position displacements, accelerations and velocities.

Tracking measurements, for example by distance sensors or rotation sensors, as shown in FIGS. 6c and 6d, make it possible to know the operational state of the pump. This can lead to a rotor disadvantage that can be caused, for example, by misalignment or by wobbly motions (FIGS. 6c and 6d) due to rotor play (caused by weakened pretension of the rotor in the stator). Movement can be monitored.

Furthermore, from the international patent application WO 2018/130718 A1 filed by the applicant, an eccentric screw pump with a conical design of the rotor and stator is known, whereby an axial can be adjusted so that the gap between the rotor and stator can be adjusted. In this construction mode of the eccentric screw pump, the ramp-up and ramp-down action of the pump can be designed by controlling the axial actuation by the relative axial actuation of the rotor and stator. If a statement about the state of wear and the operational state of the pump is available, it can be circumvented by very rapid control when high-wear operational states are detected. Such a targeted axial adjustment between the rotor and stator, so to speak in real time, can change the type of control action or feedback control loop.
Furthermore, from WO 01/88379 A1 a method and device for monitoring eccentric screw pumps in terms of measurement data that can be recorded from rotors, stators, joints, bearings, pump inlets and pump outlets is known. German patent document DE 10 2015 112 248 A1 discloses an eccentric screw pump and a method for adjusting the operating state of an eccentric screw pump. German Patent Document DE 101 57 143 A1 describes a maintenance interval indication for a pump.

Claims (19)

An eccentric screw pump,
a pump housing having a pump inlet opening and a pump outlet opening;
a stator disposed within the pump housing;
a rotor disposed within the stator;
a drive unit comprising a drive motor and a drive shaft connecting the drive motor to the rotor for transmitting torque;
with
the rotor rotating about a rotation axis is guided in the stator;
a state sensor for detecting a state variable of the eccentric screw pump;
the state sensor for detecting a state variable in the rotor or the drive shaft comprising:
located on the rotor or the drive shaft, or
located away from the rotor or the drive shaft by connecting to the rotor or the drive shaft by a signal line;
An eccentric screw pump characterized by: the state sensor is located inside the rotor or inside the drive shaft;
The eccentric screw pump according to claim 1, characterized in that: the state sensor is connected to a sensor cable and via the sensor cable to an electronic evaluation unit;
the sensor cable is routed within a portion of the drive shaft and/or within a portion of the rotor, or
the sensor cable passes through the drive shaft and optionally through a portion of the rotor;
An eccentric screw pump according to claim 1 or 2, characterized in that: The drive shaft is a wobble shaft,
connected to the drive motor at the end facing the drive motor so as to rotate about a drive shaft;
At the end facing the rotor, it is connected to the rotor for rotation about the rotor axis and for overlapping rotation about the stator axis remote from the rotor axis. ,
An eccentric screw pump according to any one of claims 1 to 3, characterized in that: 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; 2 a universal joint is inserted between the wobble shaft central portion and the rotor;
The eccentric screw pump according to claim 4, characterized in that: The sensor cable is
guided inside said first universal joint and/or said second universal joint, or
guided through the first universal joint and optionally guided through the second universal joint, or
via the perimeter of the first universal joint and/or the second universal joint;
The eccentric screw pump according to claim 5, characterized in that: the first universal joint is surrounded by a first sealing boot and the second universal joint is surrounded by a second sealing boot; or the first universal joint, the second universal joint and the wobble shaft are surrounded by a sealing sleeve and for detecting pressure within said first sealing boot and/or said second sealing boot or said sealing sleeve,
a pressure sensor is arranged in the first sealing boot and/or in the second sealing boot or in the sealing sleeve, or
a pressure line is guided in the first sealing boot and/or the second sealing boot or in the sealing sleeve, a pressure sensor being fluidly connected to the pressure line;
and,
The pressure sensor is connected for signal transmission to an evaluation unit, which utilizes the pressure sensor in the first sealing boot and/or in the second sealing boot or in the configured to detect pressure within the sealing sleeve,
The pressure sensor preferably detects the pressure of a pressurized medium, which is guided in the first sealing boot and/or in the second sealing boot or in the sealing sleeve. supplied by a pressure line connected to or by said pressure line,
An eccentric screw pump according to claim 5 or 6, characterized in that: said state sensor is connected to an electronic evaluation unit for signal transmission,
The electronic evaluation unit determines, from the state sensor data, the variance of the actual state sensed by the state sensor with respect to a predetermined target state, compares the determined variance with a predetermined allowable configured to issue an alarm signal if the calculated variance exceeds the allowable variance.
An eccentric screw pump according to any one of claims 1 to 7, characterized in that: The electronic evaluation unit comprises:
receiving the state sensor signal as the actual state;
comparing the state sensor signal to a normal state sensor signal stored as the target state;
calculating the determined variance as the difference between the state sensor signal and the normal state sensor signal;
using a predetermined allowable dispersion value as the predetermined allowable dispersion;
configured to emit a value alert signal as said alert signal;
The eccentric screw pump according to claim 8, characterized in that: The electronic evaluation unit comprises:
receiving a state sensor signal;
determining as the actual state a state change value from at least two temporally consecutive state sensor signals;
comparing the state change value to a normal state change value stored as a target state;
calculating the determined variance as the difference between the state change value and the normal state change value;
using a predetermined allowable change variance value as the predetermined allowable variance;
configured to emit a change alarm signal as said alarm signal;
An eccentric screw pump according to claim 8 or 9, characterized in that: The electronic evaluation unit comprises:
receiving a state sensor signal;
determining a state change rate from at least three temporally consecutive state sensor signals as the actual state;
comparing the state change rate to a normal state change rate stored as a target state;
calculating the determined variance as the difference between the state change rate and the normal state change rate;
using a predetermined allowable speed change as the predetermined allowable dispersion;
configured to emit a rate-of-change alarm signal as the alarm signal;
An eccentric screw pump according to any one of claims 8 to 10, characterized in that: The electronic evaluation unit comprises:
comparing a plurality of temporally consecutive actual states to a plurality of temporally consecutive target states;
Calculated from comparing the variance feature values as the determined variance,
configured to use a predetermined allowable dispersion feature value as the predetermined allowable dispersion,
An eccentric screw pump according to any one of claims 8 to 11, characterized in that: The eccentric screw pump has a rotor with a conical envelope and a conical tapered stator interior, wherein the rotor and the stator are axially opposed to each other by an axial drive. can be adjusted by
the electronic evaluation unit is connected to the axial drive for signal transmission,
actuating the drive to effect axial alignment between the rotor and the stator;
configured to detect a plurality of time-sequential status sensor signals of the status sensor during the axial adjustment operation;
An eccentric screw pump according to any one of claims 8 to 12, characterized in that: the condition sensor is located on the drive shaft or the rotor and is further connected to a condition sensor data transmission module to wirelessly transmit the condition data to a data receiver external to the eccentric screw pump;
The state sensor and the state sensor data transmission module are connected to an energy converter for receiving electrical energy, and the energy converter is disposed on the rotor or the drive shaft for kinetic energy acting on the energy converter. or configured to convert thermal energy into electrical energy,
An eccentric screw pump according to any one of claims 1 to 13, characterized in that: The energy converter is
a converter based on the principle of electromagnetic induction, which converts the relative rotational movement of the rotor or the wobble shaft with respect to the pump housing into electrical energy;
A converter based on the principle of electromagnetic induction resulting from rotation of said rotor or said wobble shaft about a rotor axis and from rotation of said rotor about an eccentric axis the converter that converts the reciprocating acceleration of the wobble shaft into electrical energy;
A converter based on the thermoelectric principle for converting a temperature gradient into electrical energy, especially between a conveyed medium and a pump component such as the rotor, the wobble shaft or the stator. said converter located in an area exposed to a temperature gradient;
selected from
15. The eccentric screw pump according to claim 14, characterized in that: Two state sensors arranged at two positions spaced from each other are arranged on the rotor, the two said positions having a phase shift of the measured state variable, said phase shift preferably comprising:
the axial spacing of two of the state sensors is greater or less than the pitch of the rotor, or
the angular spacing of the two state sensors;
realized by
16. An eccentric screw pump according to any one of claims 1 to 15, characterized in that: The state sensor is
temperature sensor, or
a pressure sensor, or
vibration sensor, or
is an acceleration sensor,
17. An eccentric screw pump according to any one of claims 1 to 16, characterized in that: A method of controlling an eccentric screw pump, comprising:
the eccentric screw pump comprising a pump housing having a pump inlet opening and a pump outlet opening;
driving the rotor into rotary motion about an axis of rotation within the stator by the drive unit;
pumping medium from a pump inlet, through the stator, to a pump outlet by a displacement effect between the rotor and the stator;
detecting a state variable of the eccentric screw pump;
including
the state variable is detected by a state sensor;
The state sensor is
located on the rotor or the drive shaft, or
positioned remotely from the rotor or the drive shaft by connecting to the rotor or the drive shaft by a signal line;
a state variable is detected in the rotor or the drive shaft;
Said eccentric screw pump preferably has a rotor with a conical envelope and a conically tapered stator interior, said rotor and said stator being axially driven by an axial drive. are tunable with respect to each other at
the rotor and the stator are axially aligned relative to each other by the drive;
detecting a plurality of time-sequential status sensor signals of the status sensor during the axial adjustment operation;
Method. detecting the state variable during pumping and performing the axial adjustment during pumping;
19. A method according to claim 18, characterized in that:

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