US20230265846A1 - State detection on eccentric screw pumps - Google Patents

State detection on eccentric screw pumps Download PDF

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Publication number
US20230265846A1
US20230265846A1 US17/921,483 US202117921483A US2023265846A1 US 20230265846 A1 US20230265846 A1 US 20230265846A1 US 202117921483 A US202117921483 A US 202117921483A US 2023265846 A1 US2023265846 A1 US 2023265846A1
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Prior art keywords
rotor
state
sensor
eccentric screw
stator
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US17/921,483
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English (en)
Inventor
Michael Rolfes
Nadja Hüdepohl
Peter Hartogh
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Vogelsang GmbH and Co KG
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Vogelsang GmbH and Co KG
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Assigned to VOGELSANG GMBH & CO KG reassignment VOGELSANG GMBH & CO KG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HARTOGH, Peter, HUDEPOHL, NADJA, ROLFES, Michael
Publication of US20230265846A1 publication Critical patent/US20230265846A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B35/00—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
    • F04B35/04—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
    • F04C2/107—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with helical teeth
    • F04C2/1071—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with helical teeth the inner and outer member having a different number of threads and one of the two being made of elastic materials, e.g. Moineau type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/022—Stopping, starting, unloading or idling control by means of pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/28—Safety arrangements; Monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C2/16—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/80—Other components
    • F04C2240/803—Electric connectors or cables; Fittings therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/80—Other components
    • F04C2240/81—Sensor, e.g. electronic sensor for control or monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2250/00—Geometry
    • F04C2250/20—Geometry of the rotor
    • F04C2250/201—Geometry of the rotor conical shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/06—Acceleration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/12—Vibration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/16—Wear
    • F04C2270/165—Controlled or regulated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/17—Tolerance; Play; Gap
    • F04C2270/175—Controlled or regulated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/18—Pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/19—Temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/80—Diagnostics

Definitions

  • the invention relates to an eccentric screw pump, having 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 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, and a state sensor for detecting a state variable of the eccentric screw pump.
  • Eccentric screw pumps are used for conveying various media in a multiplicity of applications.
  • Eccentric screw pumps operate according to the principal of a volumetric displacement pump and to this end have a rotor which is driven so as to rotate about its own rotor longitudinal axis in a stator, wherein this rotor longitudinal axis in turn is rotated about a stator longitudinal axis which is spaced apart from said rotor longitudinal axis and typically runs parallel to the latter, such that a rotation of the rotor about the stator longitudinal axis and a rotation of the rotor about the rotor longitudinal axis, as a complementary eccentric rotation, results in a superimposed movement of the rotor in the stator.
  • Eccentric screw pumps can be used for conveying volume in a defined and projectable manner in that a specific number of revolutions are carried out, the latter being proportional to the desired conveying volume.
  • Eccentric screw pumps are often used in the field of plant engineering and often serve for supplying liquid charged with foreign matter.
  • any failure of the eccentric screw pump often equates to a prolonged downtime of the entire plant, this being associated with significant disadvantages for the user.
  • a failure of an eccentric screw pump may be traced back to many causes.
  • a frequent cause of failure is excessive wear on the stator, the latter in many construction modes of eccentric screw pumps being made as a shell construction from a rubber material or another elastomer and in which a rotor made of metal is situated such that wear arising between the rotor and that the stator often has a substantial effect on the stator.
  • the wobbling mode of movement caused by the movement of the eccentric also requires a corresponding mounting and on the drive a corresponding transfer of torque by way of a wobble shaft which is often embodied with two universal joints.
  • the embodiment of the wobble shaft is thus embodied as a flexing torsion bar, for example, as a result of which the two universal joints in the drivetrain can be dispensed with and one cause of wear and failure can be avoided as a result.
  • this construction mode is not suitable for pumps with a high throughput volume because comparatively great eccentricities are advantageous to this end, and this construction mode is therefore limited to comparatively small types of pump constructions.
  • EP 2 944 819 B1 is a construction mode of an eccentric screw pump which enables a highly curtailed repair time for the replacement of a rotor or stator of the eccentric screw pump. This is achieved by a specific design of the stator flange which enables the stator conjointly with the rotor disposed therein to be pivoted outward without further pipelines that are connected to the eccentric screw pump having to be disassembled for this purpose, or without other disassembly steps being required.
  • the release of the rotor from the wobble shaft, which is required for disassembling the rotor, here can take place by way of a cavity in the rotor per se such that access to the inlet chamber for disassembling a flange disposed therein is also not required.
  • a significant advantage in the case of maintenance is indeed achieved by way of this maintenance-friendly eccentric screw pump construction. However, it is moreover desirable to forecast the requirement of maintenance, in order to be better able to plan such maintenance procedures in the regular operation of the plant.
  • the disposal of the sensor has the disadvantage that a statement pertaining to the operating pressure of the pump, and indirectly derived therefrom a statement pertaining to the torque, is to be made by means of a specific evaluation mode and by comparing calibrated comparison values, said statement to a significant degree being a function of the pumped medium and of influences in the line network at the pump exit. States of wear, in particular, such that require maintenance or require maintenance to a projectable point in time in the future, cannot be reliably detected by this detection and evaluation of measured values.
  • this can manifest itself, for example, in the start-up behavior of pumps in that a low-wear ramping up of the pump is achieved by way of a specific increase in the rotating speed, for example, this potentially differing according to the medium conveyed.
  • dry running states can be avoided in that the absence of conveyed medium is identified in real time, and the pump thereupon is stopped or operated at a highly reduced rotating speed.
  • WO 2018/130718 A1 is an eccentric screw pump having a conical design of the rotor and stator, which provides an axial adjustment possibility between the rotor and the stator and as a result enables the gap between the rotor and the stator to be adjusted.
  • the ramping up and ramping down behavior of the pump can be designed by controlling the axial actuation by an axial actuation of the rotor and the stator in relation to one another, and should knowledge pertaining to the states of wear and the operating states of the pump be available, a wear-intensive operating state, should the latter be detected, could be avoided by very rapid control, in real time, so to speak, in a targeted manner the form of a control behavior or of a feedback-control loop, by such an axial adjustment between the rotor and the stator.
  • a method and a device for monitoring eccentric screw pumps with regard to the measurement data that can be recorded from the rotor, stator, joint(s), bearing, pump inlet and pump outlet is known from WO 01/88379 A1.
  • DE 10 2015 112 248 A1 discloses an eccentric screw pump and a method for adjusting an operating state of an eccentric screw pump.
  • DE 101 57 143 A 1 describes a maintenance interval display for pumps.
  • an eccentric screw pump of the construction mode described above in which the state sensor, for detecting a state variable on the rotor or on the driveshaft, is disposed on the rotor or the driveshaft, or by means of a signal line is connected to the rotor or the driveshaft, and is disposed so as to be spaced apart from the rotor or the driveshaft.
  • a state variable is detected directly on the rotor or on the driveshaft.
  • a state variable here is to be understood to mean a physical variable which is detected by means of a sensor installation.
  • This physical variable can be, for example, a temperature, a fluid pressure, an elongation, a material stress, an alignment in relation to the direction of gravity, a speed in terms of absolute value and/or direction, or an exhilaration in terms of absolute value and/or direction.
  • This state variable is detected according to the invention either by a state sensor which, according to a first alternative, is disposed on the rotor or the driveshaft. In this first alternative, the state sensor is thus fastened directly to the rotor or the driveshaft.
  • the state sensor can be fastened to the external surface of the rotor or the driveshaft, embedded in said external surface, or be disposed in an internal cavity of the rotor or of the driveshaft and be fastened, in particular in such a manner that, proceeding from a cavity of a configured rotor or a hollow shaft as the driveshaft, the state sensor is disposed on an inner surface of this cavity, or proceeding from this cavity is disposed in a duct which extends to the external surface of the rotor or the driveshaft and optionally may also penetrate this external surface.
  • the state variable can be detected according to the invention by a state sensor which by means of a signal line is connected to the rotor or the driveshaft and per se is spaced apart from the rotor and the driveshaft.
  • the state sensor is disposed so as to be spaced apart from the rotor or the driveshaft, and is connected to the rotor or the driveshaft by means of a signal line.
  • a physically embodied signal line thus no data transmission per radio waves or the like, is embodied in order to relay a physical state variable by way of the signal line, from a detection point on the rotor or on the driveshaft, away to the state sensor.
  • a pressure which is detected directly on the surface of the rotor or the driveshaft by means of a hollow line such as a duct, a hose line, a pipeline, a bore, or the like, for example, can be directed away from the detection location and be detected by the state sensor at another location.
  • the signal line here extends from the state sensor to a terminal point which is disposed directly on the rotor or on the driveshaft, as has been explained above in the context of the state sensor disposed directly on the rotor or on the driveshaft.
  • a direct measured variable is detected on the eccentric screw pump, said measured variable enabling a direct conclusion pertaining to a measured value relevant to the operating state of the eccentric screw pump.
  • this direct detection it is possible, on the one hand, to detect directly in real time physical variables which have a direct correlation with the rotation of the rotor or the driveshaft, for example, pressure ratios, accelerations, or vibration values, such as an amplitude or a frequency of the pressure, or an acceleration caused by the rotation.
  • a temperature and the potential increase of the latter is furthermore detectable in real time at a position where a temperature peak typically arises within the entire eccentric screw pump.
  • the evaluation is significantly easier and at the same time more reliable because the influences described above are significantly reduced, and simpler methods can be applied such as, for example, a bandpass filter.
  • the state sensor rotates conjointly with the rotor or the driveshaft, respectively, and can thus detect a 360° profile, as a result of which a cross-sectional measurement of the state is achieved.
  • the validity of such a measurement is significantly better and more precise than any measurement by way of a state sensor disposed stationary on the eccentric screw pump can ever be.
  • the invention is based inter alia on the concept that an indirect detection of physical variables, and a calculation derived therefrom of critical operating parameters that can be derived therefrom has the disadvantage, on the one hand, that monitoring in real time by virtue of the necessary comparative calculations, the necessary mathematical steps per se and the necessity of comparing integral time periods herein, is not reliable and sufficiently effective to enable that an operating state which would lead to increased wear is already identified and can be avoided by corresponding control measures.
  • this is based on the concept that the disposal of the state sensor on the rotor or on the driveshaft, respectively, or the offtake of the physical measured variable from the rotor or the driveshaft, respectively, by way of a signal line, enables a detection of the state variable at that location that typically makes it possible to detect the most direct state variation with the largest value of the state variation and a minor dependence on conveying parameters such as temperature or viscosity of the conveyed medium.
  • the real time detection of the state variable on the rotor or the driveshaft, respectively is also suitable for actuating therefrom control variables of a conically embodied rotor/stator assembly such that predetermined operating states of the eccentric screw pump can be approached in a targeted manner, or predetermined operating state profiles of the eccentric screw pump can be performed in a feedback-control loop, by an axial adjustment between the rotor and the stator, or by an adjustment of the eccentricity.
  • the state sensor is disposed within the rotor or within the drive shaft, or the signal line terminates within the rotor or within the driveshaft.
  • the state variable is detected within the rotor or the driveshaft, respectively. This enables, on the one hand, a direct detection of the state variable on the eccentrically rotating component and, on the other hand, a disposal of the state sensor, and of an optionally required sensor line or energy supply of the sensor, or the signal line, respectively, so as to be protected in relation to the influence of the conveyed medium.
  • the rotor or the driveshaft can be embodied with an internal cavity, for example be configured as a roller-type rotor or as a hollow shaft, and the state sensor, or the end of the signal line, respectively, in this instance can be disposed and fastened in this cavity.
  • the state sensor is connected so as to be wired to an electronic evaluation unit by way of a sensor cable, and for the sensor cable or the signal line to run within a portion of the driveshaft and optionally within a portion of the rotor.
  • a sensor signal cable which conducts the sensor signal electrically, or as an optic fiber, or in any other way, runs from the state sensor fastened to the driveshaft or to the rotor to an electronic evaluation unit, or the signal line, in the case of a state sensor disposed so as to be spaced apart from the driveshaft or the rotor, runs through a portion of the driveshaft and optionally within a portion of the rotor. This routing enables a protected placement of the sensor signal cable, or of the signal line, respectively.
  • the sensor cable, or the signal line, respectively can extend along the entire driveshaft and along the entire drivetrain to the terminal point, or the fastening point, respectively, of the state sensor on the rotor or on the driveshaft, respectively, and herein in portions runs through the driveshaft or the rotor, or both.
  • This enables an overall protected routing of the sensor cable or of the signal line, respectively, and enables the sensor signal to be routed from the rotating shaft of the drivetrain to a stationary transmission unit by means of corresponding transmission elements.
  • the driveshaft prefferably be a wobble shaft which at the end thereof that points to the drive motor, for a rotation about a drive axle, is connected to the drive motor, and at the end thereof that points towards the rotor, for rotation about a rotor axle and for a superimposed rotation about a stator axle spaced apart from the rotor axle, is connected to the rotor.
  • the eccentric rotating movement of the rotor is transmitted by means of a wobble shaft as the driveshaft.
  • This wobble shaft on the side connected to the drive motor is mounted in a rotating manner, and on the side connected to the rotor is connected to the rotor and at this location performs the eccentric rotating movement of the rotor and the rotating movement of the rotor about the longitudinal axis of the latter.
  • This wobble shaft can in principle be embodied as a flexing bar so as to transmit a rotation about small eccentricities.
  • the wobble shaft it is particularly preferable for the wobble shaft to have a wobble shaft central portion, a first universal joint and a second universal joint, and for the first universal joint to be inserted between the wobble shaft central portion and the drive motor, and for the second universal joint to be inserted between the wobble shaft central portion and the rotor.
  • a wobble shaft which is also suitable for great eccentricities and high torques is provided by such a design embodiment in that two spaced apart universal joints are provided.
  • a universal joint in this context is to be understood to be any joint which can transmit a rotation by way of an angled routing of the shaft, for example, also a pin joint, or other construction modes.
  • the sensor cable or the signal line is particularly preferable for the sensor cable or the signal line to be routed into the first and/or the second universal joint, or to be routed through the first and optionally through the second universal joint, or to be routed about the first and/or the second universal joint.
  • Such inward routing, or through-routing, into or through the first and/or the second universal joint is advantageous in terms of a protected installation of the sensor cable and the signal line, this can, in particular, also be combined with routing the sensor cable or the signal line, respectively, through the central portion of the wobble shaft.
  • Wobble shafts having universal joints are often sealed in relation to the pumped medium by means of a sealing protective tube which is in each case disposed about each universal joint and seals the latter, or a protective tube which extends across both universal joints and the central portion of the wobble shaft is sealed in relation to the pumped medium.
  • the sensor cable or the signal line can also be installed between this protective tube and the wobble shaft, and as a result is likewise installed so as to be protected in relation to the pumped medium.
  • the sensor cable or the signal line can also be incorporated in such a protective tube, or be placed between two protective tubes disposed as a double casing, or the like, in order to protect the sensor cable also in relation to mechanical stress by the wobble shaft.
  • first universal joint to be enclosed by a first sealing boot
  • second universal joint to be enclosed by a second sealing boot
  • first and the second universal joint and the wobble shaft to be enclosed by a sealing sleeve
  • a pressure sensor to be disposed in the first and/or the second sealing boot or in the sealing sleeve, or for a pressure line to be routed in to the first and/or the second sealing boot or into the sealing sleeve
  • a pressure sensor to be fluidically connected to the pressure line in order to detect the pressure in the first and/or second sealing boot or in the sealing sleeve
  • signaling for the pressure sensor to be connected to an evaluation unit which by means of the pressure sensor is configured for detecting the pressure within the first and/or the second sealing boot or within the sealing sleeve
  • the pressure sensor preferably detects the pressure of a pressurized medium which is supplied by way of a pressure line routed into the first and/or the second sealing
  • a pressure sensor is disposed within one of the sealing boots or the sealing sleeve, or one pressure sensor is in each case disposed in each of the sealing boots, or a pressure line which accordingly is routed into a first or a second sealing boot about the first or the second universal joint, respectively, or into a common sealing sleeve of the first or the second universal joint and detects a pressure within these sealing boots, or the sealing sleeve, respectively, is used as the signal line.
  • a first pressure sensor which is disposed within the first sealing boot or is connected to a pressure line which opens into the first sealing boot, and a second pressure sensor which is disposed within the second sealing boot or is connected to a pressure line which opens into the second sealing boot can also be provided here.
  • a pressure detection within the sealing boots or the sealing sleeve respectively, a decrease or increase in pressure within this sealing boot, which indicates a leakage of the sealing boot/sealing sleeve, can be reliably and directly detected.
  • Such a leakage which will ultimately rapidly result in access of the pumped medium to the universal joints, is an event which will directly result in high wear.
  • the detection of this leak is, therefore, important in order to avoid such undesirable and high wear.
  • the invention enables the sealing sleeve to be sealed or replaced before such wear arises, such wear thereafter requiring a complex repair including the replacement of one or both universal joints and optionally further mounting elements. It is particularly advantageous here for a pressurized medium to be supplied into the sealing boot or sealing sleeve, respectively, by way of a pressure line. This to the extent that a pressure line is provided as the signal line, can also take place by way of the signal line. As a result, it is possible for a pressure to be built up and maintained within the sealing boot.
  • the state sensor the state sensor for signal transmission 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 means of the state sensor data from a predetermined target state, for comparing this determined variance with a predetermined permissible variance and, when the determined variance exceeds the permissible variance, for emitting an alarm signal.
  • the electronic evaluation unit when configured for receiving a state sensor signal as the actual state, that the state sensor signal is compared with a stored normal state sensor signal as the target state, and the determined variance is calculated as a difference between the state sensor signal from the normal state sensor signal, and to utilize a predetermined permissible variance value as the predetermined permissible variance, and to emit a value alarm signal as the alarm signal.
  • the detection of a sensor signal of the state sensor which signals an unfavorable operating state, thus an operating state that causes or will cause increased wear, is based on a comparison of target data and actual data.
  • the target data here is present in an electronically stored form, for example, as a data value, a data value profile, an algorithmic description of a data value profile, or as a comparison table having a plurality of target values for different operating states of the eccentric screw pump.
  • the target data can be predetermined and previously stored, thus be included in the eccentric screw pump ex works, so to speak, such that said target data contains characteristic values which are characteristic and constant in terms of the construction mode of the eccentric screw pump.
  • the target data can be defined by the pump-inherent constructive characteristics, such as the constant state values caused by the eccentricity, stress values defined by the drive train.
  • the target data can also be determined as a reference or calibration value when pumping a specific medium, so as to be stored thereafter.
  • This reference or calibration value can be determined by the user when initially pumping a specific medium, or when initially commissioning the pump in a specific installation situation, for example, and then be utilized for comparison in the further monitoring, thus during subsequent measurements of an actual value, such that critical changes in comparison to the original reference or calibration value can be immediately identified.
  • any variance of the actual data from the nominal data can be emitted as an alarm.
  • 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, comparing the state variation value with a stored normal state variation value as the target state, calculating the determined variance as the difference between the state variation value and the 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.
  • the electronic evaluation unit 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, calculating the determined variance as the difference between the state variation speed and the 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.
  • a state variation signal which characterizes the variation of two temporally sequential actual values is determined.
  • This state variation signal can be understood to be the first temporal derivation of the state signal, and often results in an evaluation basis for a critical operating state that has arisen or is developing that is better than the absolute value of a state signal.
  • a state variation speed can be determined from temporally sequential state sensor signals, this to be understood to be the second temporal derivation of the state signal.
  • a sizeable increase of the pressure in the eccentric screw pump can indicate a state of wear on the pressure side of the pump or a state of wear on the suction side of the pump, and can be identified at an early stage so as to establish an actuation of the eccentric screw pump as a result.
  • a sizeable increase in temperature or a sizeable variation rate of the temperature increase thus an accelerated increase in temperature, can already signal dry running even when the absolute temperature has not yet reached a critical state value.
  • a real-time response of the control of the eccentric screw pump as a result of the direct state detection on the rotor, or on the driveshaft, respectively, and the consideration of differences after the first temporal derivation or the second temporal derivation enabled as a result, can be achieved by monitoring the state, said real-time response being able to pre-empt the occurrence of damage and wear.
  • the electronic evaluation unit is configured for comparing a plurality of temporally sequential actual states with a plurality of temporally sequential target states, and 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.
  • a predetermined variance for the determined variations of the state variables, or variations of the variation speeds of the state variables is utilized in order to enable an operation within a tolerance window considered to be non-critical and to trigger a corresponding alarm when this tolerance window is exceeded.
  • the eccentric screw pump has a rotor having a conical envelope and a conically tapering stator interior, and the rotor and the stator are adjustable relative to one another in the axial direction by means of an axial actuating drive, 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 a plurality of temporally sequential state sensor signals of the state sensor during the axial adjustment process.
  • an adjustability of the radial gap between the rotor and the stator by means of a conically tapered rotor and stator is enabled in that an axial adjustment movement takes place between the rotor and the stator.
  • the stator can be embodied so as to be stationary, and the rotor can be axially adjustable.
  • the axial adjustment installation can, in particular, be embodied in such a manner that an axial adjustment of the rotor can take place in the ongoing operation, for example, in that the rotor conjointly with the wobble shaft and the drive motor can be axially adjusted.
  • an actuatable actuator can be used for example, which preferably can set a predetermined axial position by way of a path sensor.
  • the drive motor or other parts of the drivetrain can also be configured so as to be axially stationary and to be connected to the rotor by means of a torque-transmitting axial thrust connection.
  • the axial adjustment movement of the rotor typically influences the state signal and can be utilized for achieving a state signal variation.
  • at least one state signal is detected during the adjustment procedure, preferably a plurality of sequential state signals.
  • the axial adjustment movement can take place as a function of the state signals. This can thus take place by a control of the axial adjustment or a feedback-control loop in that the state signal serves as an input or command variable, and the axial adjustment movement serves as an output or control variable.
  • the axial adjustment between the rotor and the stator permits a spontaneous correction of the operating state of the eccentric screw pump.
  • Said axial adjustment can be used for optimizing a start-up procedure of the pump, for example in order to achieve a power-saving ramping up with a larger gap, and for thereafter reducing the gap upon reaching the desired rotating speed or during the ramping up.
  • the axial adjustment by means of monitoring a state signal such as the drive output, the torque or the temperature can take place until an ideal gap in terms of pump efficiency and wear is obtained between the rotor and the stator.
  • the state sensor is disposed on the driveshaft or the rotor and to be furthermore connected with 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 which is disposed on the rotor or on the driveshaft and is configured for converting kinetic or thermal energy acting on said energy converter into electric energy.
  • the state sensor is disposed as an autonomous module on the rotor or the driveshaft and wirelessly transmits the state data to a receiver spaced apart from said state sensor.
  • the energy required for detecting and transmitting the state data here is provided by way of an energy converter which is likewise disposed on the rotor or the driveshaft and is connected directly to the state sensor for transmitting energy, or is embodied as a common module with said state sensor.
  • the energy converter can be embodied such that said energy converter generates electric energy by way of induction from the rotation movement, from a resultant acceleration or vibration.
  • Other types of converters can also be used, for example thermal converters which generate electric energy from a temperature of the pumped medium.
  • the energy converter prefferably be selected from:
  • phase shift is preferably achieved by an axial spacing of the state sensors that is larger or smaller than an integral multiple of the pitch of the rotor, or by an angular spacing of the two state sensors that is unequal to an integral multiple of 360° divided by the number of pitch courses of the rotor.
  • a simultaneous, phase-shifted measurement of two state variables is achieved by this embodiment.
  • a phase shift here is understood to mean a detection of the two state variables within a periodic profile, this taking place at two points of the periodic profile that are not mutually spaced apart by exactly an integral multiple of the wavelength of the periodic profile.
  • phase shift can thus be achieved, for example, in that the two state sensors in the axial direction are indeed not mutually spaced apart, thus lie in the cross-sectional plane of the rotor, but in this cross-sectional plane have a mutual angular offset which differs from the quotient 360°/n, where n is the number of thread courses of the rotor.
  • a phase-shifted measurement in the case of a triple-turn rotor can be carried out when the state sensors are mutually offset by an angle which is not equal to 120° or equal to 240°, thus when said state sensors are mutually offset by 90° or by 180°, for example.
  • the angular offset would have to be unequal to 180° in order to achieve a phase-shifted measurement; in a quadruple-turn rotor said angular offset would have to be unequal to 90°, 180°, and 270°. It is to be taken into account here that the number of thread courses of the stator in the case of eccentric screw pumps for reasons of principle always exceeds the number of thread courses of the rotor by 1.
  • a phase-shifted measurement can also be achieved when the state sensors have an angular offset which corresponds to the quotient 360°/n, in that the state sensors are axially spaced apart by a distance which is unequal to a multiple of the pitch of the thread of the rotor.
  • the pitch here is understood to be the axial spacing of two adjacent crests of thread, and in the case of a single-turn thread corresponds to the lead, in a multi-turn thread corresponds to the quotient of lead/number of thread turns (n).
  • a phase shift can, in particular, be set in that the state sensors are mutually spaced apart by an axial distance which corresponds to half the pitch such that a phase shift by half the wavelength is achieved.
  • Particularly favorable monitoring of specific indicators of wear is achieved by the measurement using a phase shift.
  • a measured variable which is adjusted in terms of effects which arise only in one phase can be obtained, this measured variable permitting a statement to consequences of wear that arise locally in an angular range.
  • a relative statement pertaining to state variations can be obtained by comparing sensor signals that have been obtained so as to be temporally offset by the phase shift.
  • phase equality is preferably achieved by an axial spacing of the state sensors that corresponds to a multiple of the pitch of the rotor, or by an angular spacing of the two state sensors by an angle which is an integral multiple of 360° divided by the number of thread turns.
  • This embodiment is a simultaneous, phase-synchronous measurement of two state variables. This measurement mode permits a comparison of two state values detected simultaneously at different positions, and can, therefore, enable a direct conclusion pertaining to locally caused operating state variations.
  • three or more state sensors can, in particular, also be preferable for three or more state sensors to be provided, of which two state sensors are mutually disposed by a phase shift and two state sensors are disposed in equal phases, so as to combine the advantages explained above and to achieve a comprehensive statement pertaining to the operating state.
  • the state sensor prefferably be a temperature sensor, a pressure sensor, a vibration sensor, or an acceleration sensor.
  • An evaluation by means of a comparison with a previously stored and/or calibrated master curve here can offer information pertaining to a developing temperature equilibrium. Detailed analysis of the curved profile while taking into account the gradient and the curvature permit additional evaluation possibilities. In this way, the relaxation time constant correlates with the dynamic properties of the elastomer jacket of the stator, for example. A comparison of the surface integrals describes the damping performance during the running-in phase.
  • a pressure differential which can be used for calculating a volumetric flow can be determined by a measurement by means of two or more pressure sensors that are spaced apart axially along the rotor axle.
  • the user of the pump can then be warned about damage by this foreign matter and thus verify his/her pumping process so as to pre-empt damage to the pump, or a control measure which is directly derived from the state sensor signal can be carried out, for example, an emergency stop of the pump or a reduction of the rotating speed.
  • FIG. 1 shows a longitudinal sectional view of an eccentric screw pump according to the invention
  • FIG. 2 shows a longitudinal sectional view of a fragment of a first embodiment of the eccentric screw pump according to the invention
  • FIG. 3 shows a view according to FIG. 2 of a second embodiment of the invention
  • FIG. 4 a shows a longitudinal sectional partial view of a third embodiment of the invention
  • FIG. 4 b shows a view according to FIG. 4 a of a fourth embodiment of the invention.
  • FIG. 4 c shows a view according to FIG. 4 a of a fifth embodiment of the invention.
  • FIG. 4 d shows a view according to FIG. 4 a of a sixth embodiment of the invention.
  • FIG. 4 e shows a view according to FIG. 4 a of a seventh embodiment of the invention.
  • FIG. 4 f shows a view according to FIG. 4 a of an eighth embodiment of the invention.
  • FIG. 4 g shows a view according to FIG. 4 a of a ninth embodiment of the invention.
  • FIG. 4 h shows a view according to FIG. 4 a of a tenth embodiment of the invention
  • FIG. 4 i shows a view according to FIG. 4 a of an eleventh embodiment of the invention
  • FIG. 4 j shows a view according to FIG. 4 a of a twelfth embodiment of the invention
  • FIG. 4 k shows a view according to FIG. 4 a of a thirteenth embodiment of the invention.
  • FIG. 5 a shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a first embodiment
  • FIG. 5 b shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a second embodiment
  • FIG. 5 c shows a schematic illustration of the measurement procedure taking place on the wobble shaft, or on the rotor, respectively, according to a third embodiment
  • FIG. 6 a 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;
  • FIG. 6 b shows a typical schematic profile of three temperatures recorded on the rotor over time
  • FIG. 6 c 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
  • FIG. 6 d 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.
  • FIG. 1 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.
  • 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.
  • 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.
  • 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.
  • 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 30 a , which in the rotating manner is mounted in an inlet housing 50 , to a drive output end 30 b which is connected to the rotor.
  • the wobble shaft 30 at the drive output end 30 b 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.
  • 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.
  • the wobble shaft 30 on the drive input end 30 a 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.
  • 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 .
  • the rotor 20 and the stator 10 extend from an inlet end 10 a , which is fastened to the inlet housing, to an outlet housing 60 , which is fastened to an outlet end 20 a .
  • 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.
  • 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.
  • 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.
  • the senor 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 .
  • 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.
  • 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.
  • FIG. 3 shows a variant of the signal line routing.
  • the figure shows a construction which is fundamentally identical to that of FIG. 2 .
  • 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.
  • the signal line also runs through corresponding transverse bores in the pins of the two universal joints.
  • 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.
  • 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.
  • 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.
  • FIGS. 4 a - 4 k Different variants of the disposal of the sensor on the rotor are illustrated in FIGS. 4 a - 4 k .
  • the depicted sensors in these figures can be pressure sensors, temperature sensors, acceleration sensors, vibration sensors, or other sensors.
  • the variants of the disposal of the sensor depicted in FIGS. 4 a - 4 k 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. 4 a - 4 k can likewise be combined with one another.
  • FIG. 4 a 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 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 .
  • 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.
  • 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.
  • the sensor position shown in FIG. 4 a 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.
  • FIG. 4 b schematically shows a positioning of the sensor 401 identical to that of FIG. 4 a .
  • 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.
  • FIG. 4 c 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. 4 a , 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 .
  • FIG. 4 d Shown in FIG. 4 d is a further variant of the energy supply.
  • 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 .
  • FIGS. 4 e and 4 f show a variant in which two sensors 701 a , b or 801 a , 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 701 a , 701 b in FIG. 4 f 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 801 a , 801 b in FIG.
  • 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 705 a , 705 b or 805 a , 805 b , respectively.
  • FIG. 4 g shows a further variant in which two sensors 901 a , 901 b are disposed on the rotor at the same axial spacing as in FIG. 4 e , but in this case not at the same angular position.
  • the sensors are positioned so as to be mutually rotated by 180° about the rotor longitudinal axis.
  • FIG. 4 h shows a further variant of the disposal of the sensor 1001 .
  • the sensor is disposed centrally in the rotor longitudinal axis within the rotor and does not extend to an external surface of the rotor.
  • 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.
  • FIG. 4 i 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.
  • 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.
  • FIG. 4 j shows an embodiment in which a wired transmission of data or energy to the sensor 1201 is not required.
  • an energy converter 1207 here is disposed so as to be adjacent to the sensor.
  • a radio transmission module 1209 is also disposed in the rotor so as to be adjacent to the sensor in this embodiment.
  • 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.
  • FIG. 4 k 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 .
  • the senor 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.
  • FIGS. 5 a - 5 c 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.
  • FIG. 5 a 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 .
  • FIG. 5 b 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.
  • 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.
  • FIG. 5 c 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.
  • 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.
  • FIGS. 6 a - 6 d show typical profiles of some characteristic sensor signals which reflect measured parameters detectable on the rotor or the wobble shaft.
  • FIG. 6 a Plotted in FIG. 6 a 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.
  • 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 .
  • 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.
  • 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.
  • 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.
  • FIG. 6 b 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.
  • 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 ⁇ T12.
  • 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 ⁇ T12 can signal a pumping situation involving a medium with better lubricating properties and a lower temperature, for example.
  • a temperature curve T3 having a flatter profile and in relation thereto a settled constant temperature which is lower by ⁇ T13 can arise in the case of an identical conveyed medium at a lower rotating speed of the pump, for example.
  • FIG. 6 c and FIG. 6 d 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. 6 c here shows a typical curved profile for an eccentric screw pump which is in a normal operating state without any appreciable wear.
  • FIG. 6 d reflects an operating state of the pump with advanced wear.
  • FIG. 6 d 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.
  • the operating state of the pump as a result of the measurement of the trajectory shown in FIGS. 6 c and 6 d , 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. 6 c and 6 d ) due to play of the rotor (caused by a fading pre-tension of the rotor in the stator) can be identified.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
  • Details And Applications Of Rotary Liquid Pumps (AREA)
US17/921,483 2020-04-27 2021-04-27 State detection on eccentric screw pumps Pending US20230265846A1 (en)

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DE102020111386.2 2020-04-27
DE102020111386.2A DE102020111386A1 (de) 2020-04-27 2020-04-27 Zustandserfassung an Exzenterschneckenpumpen
PCT/EP2021/060932 WO2021219605A1 (de) 2020-04-27 2021-04-27 Zustandserfassung an exzenterschneckenpumpen

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JP (1) JP2023523059A (de)
CN (1) CN115443379A (de)
BR (1) BR112022020689A2 (de)
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WO (1) WO2021219605A1 (de)

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DE102019130981A1 (de) * 2019-11-15 2021-05-20 Seepex Gmbh Exzenterschneckenpumpe
DE102021121572A1 (de) 2021-08-19 2023-02-23 Hilger U. Kern Gmbh Verfahren zur Bestimmung des Verschleisszustands einer Exzenterschneckenpumpe sowie Exzenterschneckenpumpe zur Durchführung des Verfahrens
DE102021131427A1 (de) 2021-11-30 2023-06-01 Vogelsang Gmbh & Co. Kg Exzenterschneckenpumpe mit Arbeitszustellung und Ruhezustellung sowie Verfahren zum Steuern der Exzenterschneckenpumpe
DE102022110369A1 (de) 2022-04-28 2023-11-02 Audi Aktiengesellschaft Verfahren zum Betreiben eines Fluidkreislaufs für ein Kraftfahrzeug sowie entsprechender Fluidkreislauf
DE102022134734A1 (de) 2022-12-23 2024-07-04 Ruhr-Universität Bochum, Körperschaft des öffentlichen Rechts Verfahren zur Steuerung einer Exzenterschneckenpumpe

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WO2021219605A1 (de) 2021-11-04
DE102020111386A1 (de) 2021-10-28
BR112022020689A2 (pt) 2022-11-29
CN115443379A (zh) 2022-12-06
EP4143439A1 (de) 2023-03-08

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