JP2018507345A - Eccentric screw pump and method for adapting the operating condition of an eccentric screw pump - Google Patents

Abstract

An eccentric screw pump comprising a stator-rotor system comprises a rotor having a rotor screw and a stator having a female screw. The stator includes a support element and an elastomer part, and the support element surrounds at least a part of the entire circumference of the elastomer part. According to the present invention, the stator / rotor system includes an adjustment mechanism for adjusting the stator. The adjustment mechanism is coupled by the control unit to at least one sensor for measuring actual operating parameters in the stator-rotor system and / or the eccentric screw pump. The control unit can activate the adjustment mechanism taking into account the actual operating parameters measured by the at least one sensor. The invention further relates to a method for adapting the operating condition of an eccentric screw pump. [Selection] Figure 3

Description

  The invention relates to an eccentric screw pump according to the features of the premise of claim 1 and a method for adapting the operating state of the eccentric screw pump according to the features of the premise of claim 7.

  The present invention relates to an eccentric screw pump for conveying liquid and / or granular media.

  Eccentric screw pumps are in particular pumps used to transport a variety of media such as highly viscous media and abrasive media, such as sludge, liquid fertilizer, crude oil and grease. During the conveyance, the driven spiral rotor causes an eccentric motion in the stator. The stator is constituted by a housing having an inner side formed in a spiral shape. The shape axis of the rotor driven when the medium is conveyed causes an eccentric rotational movement around the stator axis. The outer screw, or stator, is configured as a double thread, while the inner screw, or rotor, is configured as a single thread. The rotor is usually made of a material with a high degree of wear resistance, for example steel, whereas the stator is made of an elastic material, for example rubber. Since the rotor and the stator have special shapes, a sealed cavity is formed between the rotor and the stator, and the medium moves along the axial direction because the cavity moves along the axial direction as the rotor rotates. In this case, since the volume of the cavity is constant, the transport medium is not compressed. If the eccentric screw pump is appropriately configured, not only fluid but also solid can be conveyed.

  The rotor is in contact with the inner wall of the stator made of an elastic material in a pressure load state in order to form a transport cavity and transport each medium with as little reverse flow as possible. Typically, a rotor made of metal typically experiences some wear on the stator by causing movement in the stator made of rubber. This wear reduces the abutment force due to the pressure load between the rotor and the stator, in particular the contact at the continuous spiral contact line along the stator and the rotor can no longer be maintained. This reduces the capacity of the eccentric screw pump. This phenomenon is particularly true for eccentric screw pumps where large suction heights or large counter pressures should be overcome. In this case, it is necessary to periodically replace the stator.

  The timing for replacing the stator is determined using, for example, a sensor that detects wear in the stator based on physical parameters. Patent Document 1 (German Patent Application Publication No. 10157143) describes a device for displaying a maintenance interval or a residual operation period of an eccentric screw pump. In this case, the sensor detects the wear-related operating parameters obtained by the control unit. Based on these parameters, the control unit calculates an expected value of an operation period or an operation cycle until a time when the next maintenance should be performed or when a specific part should be replaced.

  Patent Document 2 (German Utility Model Publication No. 202005008989) discloses an eccentric screw pump having a function of monitoring operating force and stator wear. In this case, the stator is provided with at least one measuring transducer and can measure the compression and / or movement of the stator or its elastic material as the rotor rotates.

  Other inventions for monitoring the state of the stator by the sensor include, for example, Patent Document 3 (Japanese Patent Laid-Open No. 2011-112041), Patent Document 4 (Japanese Patent Laid-Open No. 2010-281280), and Patent Document 5 (Japanese Patent Laid-Open No. 2010-281280). 2010-1104).

  Furthermore, stators are known that can be adjusted to extend their life. Patent Document 6 (German Patent Application Publication No. 3433269) describes a stator casing having tension means configured as tension bolts. In this case, the tension means is arranged over the entire axial length of the stator casing. These pulling means lead to a significant increase in weight in the stator-rotor system. In addition, each pulling means must be individually refastened when performing the readjustment.

  Patent Document 7 (European Patent Application No. 0292594) discloses a stator casing provided with a longitudinal slot and for an eccentric screw pump. The stator casing has tension means that allows pressure to be applied to the discharge area only and allows readjustment of the worn stator. In this case, the tensile force is distributed over a part of the total length of the stator casing by means of suitable reinforcing ribs.

  Patent Document 8 (German Patent Application Publication No. 4312123) describes a stator casing provided with a plurality of slots that extend in the longitudinal direction and are easily adjusted. In this case, in order to more effectively realize adjustment in the discharge side end region of the stator, each slot terminates immediately before the suction side end region of the stator and extends only in the discharge side end region. .

  Patent Document 9 (German Patent Application Publication No. 4403979) discloses an adjustable stator for an eccentric screw pump. The stator is provided with a continuous slot that extends without interruption in the longitudinal direction and a longitudinal slot that terminates just before the suction side end. Advantageously, a continuous slot is provided between each longitudinal slot.

German Patent Application No. 10157143 German Utility Model Publication No. 202005008989 JP 2011-112041 A JP 2010-281280 A JP 2010-1104 A German Patent Application Publication No. 3433269 European Patent Application No. 0292594 German Patent Application No. 4312123 German Patent Application No.4403979

  The object of the present invention is to adapt the stator-rotor system easily and quickly according to the operating conditions.

  This problem is solved by a stator-rotor system having the features of claim 1 and a method for adapting a stator-rotor system having the features of claim 7. Other advantageous embodiments are as set out in the dependent claims.

  The present invention relates to an eccentric screw pump comprising a stator-rotor system. The stator / rotor system includes a rotor having a rotor screw and a stator. According to a preferred embodiment, the stator-rotor system comprises a rotor having a single rotor screw and a stator having two female screws. The stator is composed of at least two members and includes a support element and an elastomer portion. According to embodiments of the present invention, the elastomer portion of the stator is disposed within the stator casing and typically is not rigidly coupled to the stator casing. Instead of the stator casing, a screen structure surrounding a part of the mesh frame or the elastomer part may be used as a support element. That is, the support element or stator casing and the elastomer portion are typically configured as separate members. The support element or the stator casing surrounds at least part of the entire circumference of the elastomer part. Since the support element or the stator casing in particular surrounds most of the elastomer part, only the outer free end region of the elastomer part protrudes from the support element or stator casing and is not surrounded by the support element or stator casing.

  The stator according to the invention is in particular configured as a stator system of the type described in German Offenlegungsschrift 102005042559. In this case, since the elastomer portion and the support element or the stator casing are not firmly connected, the elastomer portion can be deformed in the axial direction. The volume of the stator during deformation is kept constant. Therefore, if the elastomer portion is deformed in the axial direction, the cross section (cross-sectional area) of the long hole in the elastomer portion where the rotor is guided changes. Accordingly, the prestress, that is, the contact pressure between the stator and the rotor can be changed to compensate for the wear of the stator. Thus, by adjusting or re-adjusting the stator, it is possible to adapt the prestress between the stator and rotor in the eccentric screw pump to different operating conditions.

  The stator-rotor system of the eccentric screw pump according to the present invention includes an adjustment mechanism that enables prestress change and readjustment in the stator. Depending on the operating state of the eccentric screw pump, the prestress of the stator / rotor system must be different. The prestress depends, for example, on the viscosity of the conveyed product or product mixture. The operating state of the eccentric screw pump can be measured in particular by different operating parameters, such as pressure, rotational speed, torque, and / or other operating parameters. The adjustment mechanism is coupled to the control system and is actuated and controlled by the control system. The control system comprises in particular at least one sensor for measuring the actual operating parameters in the stator-rotor system and / or the eccentric screw pump and a control unit for adjusting the adjusting mechanism. That is, the adjustment mechanism is coupled by the control unit with at least one sensor for measuring actual operating parameters in the stator-rotor system and / or the eccentric screw pump. The operation of the adjustment mechanism by the control unit takes into account the actual operating parameters measured by the at least one sensor.

  The control mechanism according to the present invention can relate various physical parameters in the stator-rotor system to the wear state of the stator or the prestress between the stator and the rotor. In one example, physical parameters such as pressure, torque, volume flow, rotation, and / or viscosity can be related to stator wear conditions or prestress between the stator and rotor. The most prominent parameter in this case is the stress state in the elastomeric material. This stress is measured directly in the elastomeric material by the sensor system, or reaction forces occurring on other components, such as reaction forces occurring on the stator wall, in particular the support element or the stator casing, on the end face of the elastomer part. It can be measured indirectly by the reaction force that occurs in one, for example, the reaction force that occurs in the closing element that consists of two shells and holds the support element or the stator casing.

  With the adjustment algorithm according to the present invention, for example, an association is made between pressure, torque, volume flow rate, rotational speed, and prestress in the elastomer, after which an appropriate adjustment position for adjusting the adjustment mechanism is calculated, Based on the adjustment position, adjustment is made toward the optimum operating point. After automatic adjustment of the adjustment mechanism, the physical operating parameters of the eccentric screw pump are measured again to determine whether an optimal operating state has been achieved. If the measured operating parameter does not correspond to the desired nominal parameter, the adjustment stroke is calculated again and the adjustment mechanism is readjusted.

  According to a preferred embodiment of the present invention, what is actually used as a control parameter is the stress state in the elastomer, which is measured indirectly, for example, the rotational speed in an eccentric screw pump, etc. In combination with other operating parameters, the adjustment stroke x and / or the adjustment direction towards the desired nominal value is indicated, based on the incremental approximation method.

  Adjustment of the calculated adjustment process x and / or adjustment direction is preferably performed based on an incremental approximation method. That is, the adjustment of the adjustment mechanism is gradually performed particularly toward the optimum adjustment point. If the deviation between the actual operating parameter and the nominal operating parameter exceeds a specified tolerance, the adjustment mechanism is adjusted by a specified amount. The control algorithm according to the present invention defines the adjustment direction based on a comparison of actual and nominal operating parameters and data recorded in the control algorithm. In this case, the degree of adjustment corresponds to a predetermined amount. In this way, adjustments based on the incremental approximation method are made in particular to the desired nominal value until the deviation between the measured actual and nominal operating parameters is within a specified tolerance.

  According to a preferred embodiment, the adjustment mechanism comprises two adjustment elements which are arranged on the stator-rotor system and are positionally variable relative to each other. The two adjusting elements are separated from each other by a first distance in the first operating position, whereas they are separated from each other by a second distance in the second operating position. In this case, the first distance is different from the second distance. The cross section and the length of the elastomer portion of the stator at the second operating position are changed compared to the cross section and the length of the elastomer portion of the stator at the first operating position.

  Preferably, a mechanical coupling and / or a mechanical connection is provided between the adjustment mechanism and the stator, in particular in the elastomer part of the adjustment mechanism and the stator. By changing the relative distance between the two adjusting elements in the adjusting mechanism, the cross section and the length of the elastomer portion in the stator can be changed.

  Preferably, one of the adjustment elements is fixedly arranged on the stator and rotor system, and the other of the adjustment elements is arranged in a variable position on the stator and rotor system. In particular, the first adjustment element is fixedly arranged on the support element or the stator casing, and the second adjustment element is arranged variably on the elastomer part of the stator. According to a preferred embodiment, the first adjustment element is fixedly arranged on a flange provided at the free end of the support element or the stator casing, and the position-variable second adjustment element is free of the elastomer part in the stator. Located on the edge.

  According to a preferred embodiment of the invention, the actuator is actuated by the control unit, and the position-adjustable second adjustment element is relocated by the actuator. Thereby, the relative distance between the position variable second adjustment element and the fixed first adjustment element changes. The relative distance between the two adjustment elements can be adjusted by different means. As the actuator, for example, a wedge element, a tapering ring, a spindle adjustment mechanism, and a cylinder auxiliary mechanism can be used.

  According to a preferred embodiment of the invention, at least one first sensor can be arranged on a stationary component assigned to the stator-rotor system in the eccentric screw pump, by means of the first sensor, Certain physical parameters in the stator-rotor system can be detected. Alternatively or additionally, at least one second sensor can be arranged on the stator-rotor system, in particular on the elastomer part of the stator. Furthermore, alternatively or additionally, at least one third sensor can be arranged on the adjusting mechanism.

  For example, at least one first sensor is configured to measure pressure, rotational speed, torque, temperature, and / or volume flow in an eccentric screw pump, while at least one second sensor is And configured to directly or indirectly measure prestress between the stator and rotor in the stator-rotor system. The second sensor can be configured as, for example, a piezoelectric element, a load cell, or a dielectric elastomer. Furthermore, the second sensor can be configured to measure the reaction force of the elastomer material, whereas the at least one third sensor is a position of the position-variable second adjustment element and / or a fixed first It can be configured to measure the relative distance between the adjustment element and the second variable position adjustment element.

  The invention also relates to a method for adapting the operating condition of an eccentric screw pump comprising a stator-rotor system as described above.

  In the method of the present invention, first, the actual operating state of the eccentric screw pump is determined. In this case, in order to determine the actual operating state in the eccentric screw pump, at least one of the actual physical operating parameters in the eccentric screw pump is measured by an appropriate sensor and / or the stator is measured by an appropriate sensor. Measuring at least one of the actual physical operating parameters in the elastomer part of the rotor system and / or measuring at least one of the actual physical operating parameters in the adjusting mechanism by means of suitable sensors; The actual operating parameter measured by the sensor is then compared to a known nominal operating parameter or a desired nominal operating parameter. If the measured actual operating parameter deviates from the nominal operating parameter, the adjustment mechanism is activated to adjust the stator. In this case, the adjustment to the new operating state is monitored while controlling at least one of the actual physical operating parameters.

  According to the first preferred embodiment, when the measured actual operating parameter deviates from the nominal operating parameter, the adjustment process of the adjusting mechanism is calculated, and the calculated adjusting process is adjusted by operating the adjusting mechanism. Is done. As a result, readjustment or adjustment of the stator is performed, and in particular, the cross section and length of the elastomer portion in the stator change.

  According to an alternative embodiment, the operating state is adjusted towards the ideal operating point based on an incremental approximation method. In this case, the control principle or control algorithm is based on the functional characteristic of assigning the volume flow rate to the first rotational speed of the eccentric screw pump. That is, when the volumetric efficiency is 100%, the volumetric flow rate is exactly the same as the amount conveyed from the suction side to the discharge side by the individual conveying elements (conveying cavities) in the eccentric screw pump, in particular according to the rotational speed.

  The optimum adjustment for the ideal operating point in the eccentric screw pump is performed as follows. If the volume flow rate at a constant rotational speed over a specific adjustment range is observed, it can be confirmed that the volume flow rate is substantially constant over a large adjustment range. However, the required torque is not constant. When the prestress is released by adjusting or rearranging the adjustment element in the adjustment mechanism, the prestress is reduced due to a reduction in friction loss based on the reduction. The efficiency of the eccentric screw pump is increased in a large range where the backflow does not occur or the volumetric flow does not change because the backflow is slight. The efficiency of the eccentric screw pump does not decrease until it reaches the operating point where the backflow increases due to the reduced prestress. The point where the maximum efficiency is exhibited can be defined as follows. In other words, the ideal operating point in the pump is located in a range where the prestress between the rotor and the stator is sufficiently large so that backflow does not occur or hardly occurs. Thus, the ideal operating point refers to the point at which the required prestress is generated for the stator-rotor system, thereby producing the required back pressure while minimizing media backflow.

  This functional characteristic is applied to the control algorithm according to the present invention. In this case, an incremental approximation method is used in particular to make adjustments towards the ideal operating point. According to a preferred embodiment of the present invention, the control algorithm preferably utilizes the following measurement principle: In this case, first, the operating parameters in the eccentric screw pump are measured. These operating parameters include, for example, pressure, rotational speed, torque (motor current), or other operating parameters, and are measured by appropriate sensors. The volume flow rate can also be measured by, for example, a volume flow meter or a measurement diaphragm.

  The adjustment mechanism is then adjusted to at least a substantially closed position, for example a position where the two adjustment elements are as close as possible to each other. This compresses the rubber in the elastomer portion, thus increasing prestress in the stator-rotor system and minimizing backflow.

  After a sufficiently compressed region is obtained, it is gradually opened again while controlling the adjusting mechanism. In this process, the volume flow rate is initially maintained constant up to a specific point. At this particular point, the volume flow is reduced due to the increased backflow in the stator-rotor system. The ideal operating point is located just before the point where the volume flow rate drops. The ideal operating point can also be regarded as a certain range in which the eccentric screw pump can achieve maximum efficiency.

  The adjustment of the prestress is preferably performed autonomously at regular time intervals by an adjustment mechanism in the stator / rotor system. This ensures active adjustment or adaptation to changes in operating conditions in the pump.

  Alternatively, the pre-stress in the stator-rotor system can be increased until a maximum volume flow is reached based on measured operating parameters and adjustment by incremental approximation. After reaching the maximum volume flow, the prestress is gradually increased by a specified number of adjustments. This ensures that iBP is exceeded. After that, if the prestress is gradually released, iBP is measured and adjustment to iBP is performed. If this process is repeated at regular time intervals, it is possible to cope with changes in the operating state of the eccentric screw pump.

  According to a preferred embodiment, after adjusting the adjusting mechanism, the actual operating state of the eccentric screw pump is again determined and compared with the nominal operating parameters after a predetermined time interval. Thereby, it can be determined whether or not the adjustment has been performed accurately. If the actual operating parameter in the eccentric screw pump still deviates from the nominal operating parameter, in particular if the deviation exceeds a specified tolerance, the adjustment mechanism is actuated again to make the adjustment. If adjustment of the adjustment mechanism, and thus the readjustment or adjustment of the stator, sufficiently reduces the deviation between the actual and nominal operating parameters, no further adjustments are made. Instead, the operating condition of the eccentric screw pump is determined again by means of the sensor-based measurement described above after a further specified time interval.

  However, in the first judgment in the eccentric screw pump, if the actual operating parameters do not deviate from the nominal operating parameters, especially if the deviation does not exceed the specified tolerance, The actual operating condition in the eccentric screw pump is again determined by measuring the operating parameter and comparing the actual operating parameter with the nominal operating parameter. By regularly determining the actual operating condition of the eccentric screw pump at regular time intervals, the stator-rotor system can be constantly monitored. Thereby, at the time of the operation of the eccentric screw pump, the deviation from the desired operating state can be quickly adjusted and adapted to the desired operating state.

  According to one embodiment of the present invention, the pressure, rotational speed, torque, temperature, and / or volume flow rate of the eccentric screw pump is measured by a suitable sensor. Alternatively or additionally, the prestress between the rotor and the stator and / or the reaction force of the elastomer material in the elastomer part is measured. Furthermore, by means of a suitable sensor, the position of at least one adjustment element in the adjustment mechanism and / or the relative distance between two adjustment elements in the adjustment mechanism can be measured.

  According to a preferred embodiment of the present invention, the adjustment mechanism comprises two adjustment elements that are variable in distance. In this case, the adjustment mechanism adjusts by enlarging or reducing the relative distance between the two adjustment elements. A change in the distance between the two adjustment elements changes the cross-section and length of the elastomer portion coupled to the stator-rotor system. In this case, the control mechanism calculates the nominal distance between the two adjustment elements on the basis of the physical parameters measured by the appropriate sensors with respect to the stator-rotor system, in particular the adjustment process of the position-variable second adjustment element. Is calculated. Then, the adjustment mechanism is operated, and the second adjustment element is adjusted toward the calculated position with respect to the position-variable second adjustment element, in particular by adjusting the distance calculated between the two adjustment elements. The physical operating parameters are then measured again after a further time interval. If the deviation from the desired and actual operating parameters is reduced, it means that the eccentric screw pump has been adjusted to a new operating state. This new operating state of the eccentric screw pump can be brought closer to the desired and optimal operating state by further readjustment or adjustment. If the deviation from the desired and actual value is not reduced, further adjustment of the adjustment mechanism is performed. Thus, the present invention relates to a stator-rotor system for an eccentric screw pump and control of the stator-rotor system. The present invention particularly relates to an automatic control system for changing the prestress between the stator and rotor in an eccentric screw pump, i.e. an elastomer part which is a soft component and a support element which is a hard component, e.g. a so-called stator. The invention relates to an automatic control system for changing the prestress between the casing. One of the major advantages of the present invention is that the energy efficiency of the stator-rotor system can be greatly increased because the eccentric screw pump can always operate at the optimum operating point.

  By automatically controlling the prestress, in particular, automatic wear compensation is possible, so that the life of the stator can be extended. When the eccentric screw pump is switched on / off, the initial separation torque can be reduced by adjusting the stator based on a prescribed procedure.

  Furthermore, an automatic control system can advantageously adapt the prestress between the stator and the rotor to the viscosity of the transport medium.

  The method according to the present invention may comprise one or more features and / or characteristics in the above-described device as an alternative or addition to the above-described features. Similarly, the above-described apparatus may comprise one or more features and / or characteristics in the above-described method.

FIG. 10 is a schematic partial view showing a conventional stator / rotor system. 1 is a schematic partial view illustrating a first embodiment of a stator / rotor system including an adjusting mechanism according to the present invention. It is the schematic which shows the sequence of the control mechanism for adjusting a stator rotor system. It is a graph which shows an ideal operating point as a function of the adjustment process in an adjustment mechanism.

  Hereinafter, embodiments and advantages of the present invention will be described in detail with reference to the accompanying drawings. The dimensional ratio between individual elements in the drawings does not necessarily represent the actual dimensional ratio. This is because some elements are displayed in a simplified manner from the standpoint of enhancing clarity, and some other elements are displayed in an enlarged manner.

  In the drawings, the same elements or elements having the same action are represented by the same reference numerals. From the standpoint of increasing clarity, reference numerals in the individual drawings are limited to those necessary for the description of the individual drawings. Each embodiment in the drawings is merely illustrative of the apparatus and method according to the present invention and is not limiting.

  FIG. 1 shows a schematic partial view of a conventional stator-rotor system 1 for an eccentric screw pump. Such a system 1 typically includes a rotor (not shown) configured as a single metal thread and a stator 3 configured as a double thread. During operation of the eccentric screw pump, the rotor geometry axis produces an eccentric rotational movement about the stator longitudinal axis X3. The stator 3 includes an elastomer portion 4 and a stator casing 5, and the elastomer portion 4 and the stator casing 5 are not firmly connected.

  FIG. 2 shows a schematic partial view showing a first embodiment of a stator / rotor system 10 comprising an adjusting mechanism 12 according to the invention for readjusting or adjusting the stator 3. The adjustment mechanism 12 includes a fixed first adjustment element 13 and a position-variable second adjustment element 14. If the distance between the two adjusting elements 13 and 14 changes, deformation of the elastomer occurs, so that the cross section and / or length of the elastomer portion 4 of the stator 3 changes. Thereby, the elastomer part 4 of the stator 3 is readjusted or adjusted. In particular, the flange 23 of the stator casing 5 functions as a fixed adjusting element 13 and the actuating element 24 arranged at the free end 8 of the elastomer part 4 functions as a position-variable adjusting element 14.

  The adjustment mechanism 12 is coupled to the control system 30 and is actuated and controlled thereby. The control system 30 comprises a control unit 32 and at least one sensor 35 for measuring physical operating parameters in the stator-rotor system 10 or the eccentric screw pump. In particular, the eccentric screw pump is provided with at least one first sensor 36 for measuring the pressure, rotational speed, temperature and / or volume flow of the pump. Furthermore, at least one second sensor 37 can be arranged in the elastomer part 4 and, for example, a prestress between the rotor and the stator 3 or a reaction force in the elastomer part can be measured. In addition, the adjustment mechanism 12 can be provided with at least one third sensor 38, for example the position of the position variable adjustment element 14 or the relative distance between the fixed adjustment element 13 and the position variable adjustment element 14. Can be detected. Data obtained by the sensor is transmitted to the control unit 32. In this case, the control unit 32 compares the transmitted data with the nominal operating parameters and, if the measured actual operating parameters deviate from the nominal operating parameters, the adjustment of the adjustment system 12, in particular a fixed Adjustments are made to change the relative distance between the adjustment element 13 and the variable position adjustment element 14, thereby changing the deformation of the elastomer and thus the cross section and / or the length of the elastomer part 4 in the stator 3.

  FIG. 3 schematically shows a control mechanism sequence for adjusting the stator-rotor system 10 according to FIG. The control mechanism according to the present invention can relate various physical parameters in the stator-rotor system 10 or the eccentric screw pump to the wear state of the stator 3 or the prestress between the stator 3 and the rotor of the eccentric screw pump. As an example, physical parameters such as pressure, volume flow rate, rotation, and / or viscosity can be related to the wear state of the stator 3 or the prestress between the stator 3 and the rotor. The most prominent parameter in this case is the stress state in the elastomeric material. This stress is measured directly in the elastomer material by the sensor system 37 or reaction forces occurring in other components, for example the stator wall, in particular the stator casing 5, the end face of the elastomer part 4, the stator casing 5 The closing element can be measured indirectly by the reaction force generated on the rotor in the stator-rotor system 10.

  Alternatively and / or additionally, parameters that can be measured on the eccentric screw pump, such as pump pressure, rotational speed at which the eccentric screw pump operates, temperature, volumetric flow rate of the carrier medium, can also be used.

  With the adjustment algorithm according to the present invention, for example, an association is made between the pressure, the volume flow rate, the rotation speed, and the required prestress, and then an appropriate adjustment process for adjusting the adjustment mechanism 12 is calculated and the adjustment is performed. Based on the stroke, adjustments are made to the optimum operating point. In a particularly conceivable embodiment, a sensor 38 that measures the actual condition in the adjustment system, in particular a sensor that measures the relative distance between the position variable adjustment element 14 or the fixed adjustment element 13 and the position variable adjustment element 14. 38 is provided and / or a sensor 38 is provided to monitor the desired nominal position as the position of the position variable adjustment element 14 is adjusted.

  Information on the operating state of the eccentric screw pump can be obtained from the operating parameters measured by the sensor. These operating parameters are compared by the control unit 32 (see FIG. 2) with defined operating parameters recorded, for example, in a characteristic diagram or graph of the control unit 32. In this case, the control system will not react if the comparison does not deviate between the actual and nominal operating parameters. Since the actual operating parameters are measured and compared again after the time interval Δt1, the operating condition of the eccentric screw pump or the operating condition of the stator rotor system 10 is regularly monitored or controlled.

  In contrast, if the comparison reveals a deviation between the actual operating parameter and the nominal operating parameter, the control unit 32 calculates the necessary adjustment for the adjusting mechanism 12 based on the recorded characteristic diagram or graph. Activate the adjustment mechanism. After the adjustment mechanism 12 has been adjusted automatically, the physical operating parameters of the eccentric screw pump or the stator-rotor system 10 are measured again after a further time interval Δt2, so that the optimum operating condition is It is determined whether it was obtained or maintained. In this case, if the measured operating parameter does not correspond to the desired nominal operating parameter, the control unit 32 recalculates the adjustment process and readjusts the adjustment mechanism 12. The control algorithm specifically makes the incremental adjustments described below in connection with FIG.

  In an eccentric screw pump, after the desired optimum operating state is achieved by adjustment, permanent monitoring is performed by periodically measuring operating parameters at a specified time interval Δt3, and adjustments are made as necessary. The mechanism is readjusted. This achieves an optimal deformation of the elastomer and thus an optimal operating state during operation of the eccentric screw pump.

  FIG. 4 shows the adjustment of the ideal operating point as a function of the adjustment stroke n in the adjustment mechanism. A specific volume flow Q is assigned to a specific rotational speed in the eccentric screw pump. When the volumetric efficiency is 100%, the volumetric flow rate Q corresponds in particular exactly to the amount conveyed from the suction side to the discharge side by the individual conveying elements (conveying cavities) in the eccentric screw pump according to the rotational speed.

  The optimum adjustment for the ideal operating point iBP in the eccentric screw pump is performed as follows. If the volume flow rate Q at a constant rotational speed over a specific adjustment stroke n is observed, it can be confirmed that the volume flow rate Q is substantially constant over a large adjustment stroke n. However, the required torque (not shown) is not constant. When the prestress is released by adjusting or rearranging the adjustment element in the adjustment mechanism, the prestress is reduced due to a reduction in friction loss based on the reduction. The efficiency of an eccentric screw pump is typically increased in a large adjustment range in which the volume flow Q does not change at least substantially because no backflow occurs or there is little backflow. The efficiency of the eccentric screw pump does not decrease until the operating point at which the backflow increases is reached. The point where maximum efficiency is exhibited refers to an ideal operating point and can be defined as follows. That is, the ideal operating point in the pump is located within the range of the adjustment stroke n in the adjustment mechanism, where the prestress between the rotor and stator is sufficiently large so that no or little backflow occurs. Therefore, the ideal operating point iBP refers to the point where the prestress required for the stator-rotor system is generated, thereby producing the required back pressure without media back flow.

This functional characteristic is applied to the novel control algorithm according to the present invention. In this case, an incremental approximation method is used particularly toward the ideal operating point iBP. According to one embodiment of the present invention, the control algorithm utilizes the following measurement principle.
1. The operating parameters in the eccentric screw pump, such as pressure, rotational speed, torque (motor current) and possibly volumetric flow rate Q are measured. This measurement is performed by, for example, a volume flow meter or a measurement diaphragm.
2. The stator / rotor system is adjusted by the adjusting mechanism. In this case, the fixed adjustment element is adjusted to be closed. In this adjustment, since the rubber in the elastomer portion is compressed, the backflow = 0 or almost zero. The volume flow rate Q decreases particularly with increasing compression. This is because the cavity volume in the eccentric screw pump pump is gradually reduced.
3. After the fully compressed area is obtained, the adjustment mechanism is opened again. In this case, the volume flow rate Q is initially maintained constant up to a specific point. At this specific point, the backflow in the stator-rotor system increases, so the volume flow Q decreases. The ideal operating point iBP is located immediately before the point where the volume flow rate Q decreases. A sufficiently compressed region can be measured, for example, based on a measured value of the volume flow rate Q. If the adjusting mechanism is closed, the volume flow rate Q increases. If the volume flow rate Q does not change or the volume flow rate Q slightly decreases, it means that the maximum value has been exceeded.
4). Adjustment according to measurement principle 3 is autonomously performed in the stator / rotor system at regular time intervals. This ensures active adjustment or adaptation to accommodate changes in operating conditions at the pump.

  The invention has been described with reference to the preferred embodiments. However, it is obvious to those skilled in the art that modifications or changes can be made to the present invention within the scope of the appended claims.

DESCRIPTION OF SYMBOLS 1 Stator rotor system 3 Stator 4 Elastomer part 5 Stator casing 8 Free end
10 Stator rotor system
12 Adjustment mechanism
13 Fixed first adjustment element
14 Position adjustable second adjustment element
23 Flange
24 Actuating elements
30 Control system
32 Control unit
35 sensors
36 First sensor
37 Second sensor
38 3rd sensor △ t Time interval
iBP Ideal operating point n Adjustment process Q Volume flow X Longitudinal axis

Claims (17)

An eccentric screw pump comprising a stator-rotor system (10) comprising a rotor having a rotor screw and a stator (3) having an internal thread, said stator (3) comprising a support element (5) and an elastomer part (4) Wherein the support element (5) surrounds at least part of the circumference of the elastomer part (4),
The stator / rotor system (10) includes an adjustment mechanism (12) for adjusting the stator (3), and the adjustment mechanism (12) is controlled by the control unit (32). And / or coupled to at least one sensor (35) for measuring actual operating parameters in the eccentric screw pump;
Eccentric screw characterized in that the control unit (32) can actuate the adjustment mechanism (12) taking into account the actual operating parameters measured by the at least one sensor (35) pump. The eccentric screw pump according to claim 1, wherein the adjusting mechanism (12) comprises two adjusting elements (13, 14) arranged in the stator-rotor system (10), The adjusting elements (13, 14) are variable in distance relative to each other;
Since the mechanical coupling part and / or the mechanical connection part are provided between the adjustment element (13, 14) of the adjustment mechanism (12) and the stator (3), the two adjustment elements An eccentric screw pump in which the cross section and length of the elastomer portion (4) in the stator (3) can be changed by changing the relative distance between (13, 14).   The eccentric screw pump according to claim 2, wherein the first adjustment element (13) is fixedly arranged on the stator-rotor system (10), and the other second adjustment element (14) is Eccentric screw pump arranged in a variable position on the stator / rotor system (10).   4. The eccentric screw pump according to claim 3, wherein the second adjustable element (14), which is variable in position, can be repositioned by means of an actuator actuated by the control unit (32). An eccentric screw pump capable of changing a distance of the second adjustment element (14) whose position is variable with respect to the first adjustment element (13).   5. The eccentric screw pump according to claim 1, wherein at least one first sensor (36) is arranged on the eccentric screw pump and / or at least one second screw pump. A sensor (37) is arranged on the elastomer part (4) of the stator (3) and / or at least one third sensor (38) is arranged on the adjusting mechanism (12); Eccentric screw pump.   The eccentric screw pump according to claim 5, wherein the first sensor (36) is configured to measure pressure, rotational speed, temperature and / or volume flow in the eccentric screw pump and / or A second sensor (37) is configured to measure the prestress and / or reaction force of the elastomer material in the elastomer portion (4) and / or the third sensor (38) is position-variable. Configured to measure the position of the second adjustment element (14) and / or measuring the distance between the fixed first adjustment element (13) and the variable second adjustment element (14) An eccentric screw pump configured as described above. A method for adapting the operating condition of an eccentric screw pump comprising a stator-rotor system (10), comprising:
The stator / rotor system (10) includes a rotor, a stator (3), and an adjustment mechanism (12) for adjusting the stator (3).
The stator (3) comprises an elastomer part (4) and a support element (5),
The method
a. To determine the actual operating condition in the eccentric screw pump, measure at least one of the actual physical operating parameters in the eccentric screw pump by means of a suitable sensor and / or by means of a suitable sensor Measuring at least one of the actual physical operating parameters in the elastomer part (4) and / or measuring at least one of the actual physical operating parameters in the adjusting mechanism (12) by means of a suitable sensor When,
b. comparing at least one of said actual operating parameters with a known nominal operating parameter;
c. operating the adjusting mechanism (12) to adjust the stator (3) if the measured actual operating parameter deviates from the nominal operating parameter;
d. monitoring adjustment to a new operating state while controlling at least one of the actual physical operating parameters;
Including methods. 8. The method of claim 7, wherein if the measured actual operating parameter deviates from the nominal operating parameter, an adjustment stroke (n) of the adjustment mechanism (12) is calculated,
A method in which the calculated adjustment process (n) is performed by operating the adjustment mechanism (12), thereby adjusting the ideal operating point (iBP) in the stator (3).   8. The method of claim 7, wherein if the measured actual operating parameter deviates from the nominal operating parameter, the operating state is made to an ideal operating point (iBP) using an incremental approximation method. How to adjust by adjusting towards.   10. The method according to claim 9, wherein the adjusting mechanism (12) is adjusted to at least a substantially closed position where prestress in the stator-rotor system (10) increases, after which the adjusting mechanism (12). ) Is controlled and released to adjust the ideal operating point (iBP) at which the eccentric screw pump operates at maximum efficiency.   11. The method according to any one of claims 7 to 10, wherein after the regulation mechanism (12) has been adjusted and after a specified time interval (Δt2) has elapsed, the actual operation of the eccentric screw pump. Redefining the parameters and comparing them to the nominal operating parameters.   12. A method as claimed in claim 11, wherein if the actual operating parameter deviates from the nominal operating parameter, the adjusting mechanism (12) is operated again.   12. The method according to claim 11, wherein when the deviation between the actual operating parameter and the nominal operating parameter is sufficiently reduced, the eccentric screw pump adjusts after a specified time interval (Δt3). A method for re-determining the activated state.   12. The method according to any one of claims 7 to 11, wherein the eccentric screw is threaded after a specified time interval ([Delta] t1) when the actual operating parameter does not deviate from the nominal operating parameter. Redefining and comparing the actual operating parameters of the pump with the nominal operating parameters.   15. The method according to any one of claims 7 to 14, wherein the pressure, rotational speed, temperature and / or volume flow rate in the eccentric screw pump is measured with a suitable sensor and / or a suitable sensor. To measure the pre-stress between the rotor and the stator (3) and / or to measure the reaction force in the elastomer material of the elastomer part (4) and / or to use a suitable sensor. Measuring the position of at least one adjustment element (13, 14) in the adjustment mechanism (12) and / or by means of suitable sensors, the two adjustment elements (13, 14) in the adjustment mechanism (12) 14) How to measure the distance between. 16. The method according to any one of claims 7 to 15, wherein the adjustment of the adjustment mechanism (12) reduces or enlarges the distance between two adjustment elements (13, 14) in the adjustment mechanism. By doing
A method in which the cross-section and length of the elastomer portion (4) in the stator-rotor system (10) is changed by changing the distance between the two adjusting elements (13, 14).   17. A method according to any one of claims 7 to 16, wherein the adjustment mechanism is activated only when the defined deviation exceeds a specified tolerance.

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