EP3250828B1 - Stator-rotor system and method for adjusting a stator in a stator-rotor system - Google Patents

Description

The present invention relates to a stator-rotor system and a method for adjusting a stator in a stator-rotor system according to the features of the preambles of claims 1 and 12.

State of the art

The present invention relates to a stator-rotor system of an eccentric screw pump for conveying liquid and / or granular media with an adjustable or adjustable stator.

Eccentric screw pumps are pumps for pumping a variety of media, especially viscous, highly viscous and abrasive media such as sludge, liquid manure, petroleum and fats. The driven, coiled rotor rolls in the stator. This is a housing with a helical spiral inside. The rotor performs an eccentric rotary movement about the stator axis with its figure axis. The outer snail, i.e. the stator, for example, has the form of a two-start thread, while the rotor worm is only one-start. The rotor is usually made of a highly abrasion-resistant material, such as steel. The stator, on the other hand, is made of an elastic material, for example rubber. The special shape of the rotor and stator creates sealed cavities between the rotor and stator, which move axially when the rotor rotates and convey the medium. The volume of the cavities is constant so that the fluid is not squeezed. With a suitable design, eccentric screw pumps can not only convey fluids, but also solid bodies.

In order to form the delivery spaces and to be able to convey the respective medium with as little reflux as possible, the rotor is pressurized against an inner wall of the stator formed by elastic material. Due to the movement of the generally metallic rotor within the stator, which is usually made of rubber or a similar material, there is some abrasion or wear of the stator. The wear on the pressurized contact force between the rotor and the stator is reduced; in particular, the contact between the stator and the rotor cannot be maintained along an uninterrupted helical contact line, as a result of which the performance of the eccentric screw pump decreases. This applies in particular to pumps that have to overcome a high suction head. For this reason, the stator must be replaced and replaced at regular intervals.

In order to determine the time of replacement of the stator, sensors are used, for example, which detect the wear of the stator on the basis of physical parameters.

Alternatively, embodiments are known in which the stator can be adjusted to compensate for wear. For example, the voltage in the stator-rotor system can be adjusted by changing the stator diameter.

DE 3433269 A1 describes a stator jacket with tensioning devices in the form of tension bolts, which are distributed over the entire axial length of the stator jacket. This causes a significant increase in the weight of the stator-rotor system. In addition, all clamping devices must be retightened individually for adjustment.

DE 3641855 A1 describes an adjustable stator with an elastomer body, which is vulcanized into a tubular jacket divided into segments on the circumference by longitudinal slots, and at least one clamp that encompasses the tubular jacket.

EP 0292594 A1 discloses a stator jacket for eccentric screw pumps provided with a longitudinal slot, which has a tensioning device for generating pressure and for adjusting when the stator wears only in its pressure range. The voltage is partially distributed over the length of the stator sheath using suitable reinforcing ribs.

DD 279 043 A1 describes a stator for an eccentric screw pump, which can be retightened and enables a correction of wear-related gap losses along the helically wound stator interior. The stator is conical and axially retensionable in a sleeve with an inner cone. Retensioning is carried out with a clamping nut that spans the sleeve. The contacting conical outer surfaces of the stator and sleeve create a spatial Distribution of the clamping forces and thereby the narrowing of the stator interior required for the correction of the gap losses.

FR 1 155 632 A describes a screw pump, comprising a screw and a support element formed from an elastic material and surrounded by a housing. The support element is divided into different sectors. At least one projection is assigned to each sector, via which pressure is generated on the respective sector and thus on the housing and on the support element. The pressure of the projections to be applied is set, for example, by the inclined surfaces of a telescopic threaded sleeve.

DE 4312123 A1 describes a stator jacket with several longitudinal slots that simplify the adjustment. So that readjustment can be carried out better in the area of the pressure-side end of the stator, the slots end shortly before the end of the suction-side end of the stator and only run freely at the pressure-side end.

DE 4403979 A1 discloses an adjustable stator for progressing cavity pumps with continuous longitudinal slots and longitudinal slots that end at a short distance from the suction end of the stator. Advantageously, a continuous slot follows each longitudinal slot.

DE 10200393 A1 describes an eccentric screw pump with a partially retensionable stator. In this case, an axially non-continuous clamping gap is provided in the stator jacket encompassing the elastomeric stator core. The web remaining on the entry side forms a tension lock on this side. The stator is re-tensioned by means of a tensioning device which is arranged in a region of the stator jacket with a tensioning gap.

Furthermore, according to DE 2331173 a device is known in which the stator is readjusted by partially pressing in the stator elastomer at certain lines or points of the stator. For this purpose, the stator comprises helical strips in areas of particularly high wear. By adjusting the helical strips, the positions of the areas of the internal thread surface of the stator formed by the straight-line sections in cross section are changed in their position in the radial direction. As a result, even a heavily worn stator lining can be deformed in such a way that it returns to its original cross-sectional shape.

Another possibility provides that a fluid is pressed in between the wall of a stator jacket and the elastomer part, as a result of which the stator diameter is changed. According to one in the US 3139035 described variant, fluid is filled into inflatable tubes, which increases the pressure on the rotor.

The above-described prior art has a number of disadvantages. Due to the many setting options on the different systems, the respective handling is difficult. In particular, in the systems described there is no feedback about the level of the voltage between the stator and the rotor. The setting should therefore only be made by experienced operating personnel, otherwise the risk of incorrect operation is high. If the voltage is increased too much, the pump works poorly and the wear on the stator is further increased.

With the systems described above, it is only possible to compensate for stator wear, but not to adapt to the prevailing operating conditions.

The object of the invention is to make the clamping force of the elastomer of the stator to the rotor in the stator-rotor system of the eccentric screw pump variable to compensate for the wear of the stator and for which the backflow can be kept low even after a long period of operation. Furthermore, influences of the medium on the elastomer in the system should be able to be compensated.

The above object is achieved by a stator-rotor system and a method for adjusting a stator in a stator-rotor system, which comprise the features in claims 1 and 12. Further advantageous configurations are described by the subclaims.

description

The invention relates to a stator-rotor system for an eccentric screw pump. Such a stator-rotor system comprises a rotor with a rotor screw and a stator with an internal thread. The stator can be constructed, for example, in two parts and in particular comprise a support element, for example a stator jacket, and an elastomer part, the elastomer part of the stator being arranged in the support element or stator jacket and having no fixed connection to the support element or stator jacket. Alternatively, for example, a fabric surrounding the elastomer part can be used as the support element. This means that the support element or the stator casing and the elastomer part can preferably be designed as separate parts. The support element or the stator sheath completely surrounds the elastomer part at least in some areas. In particular, the support element or the stator casing surrounds the majority of the elastomer part, so that only the free outer end regions of the elastomer part protrude beyond the support element or the stator casing and are not enclosed by the latter.

In particular, the stator is a stator system as shown in FIG DE 102005042559 A1 is described. Due to the lack of a firm connection between the elastomer part and the support element or stator jacket, an axial deformation of the elastomer part is possible. In the event of deformation, the volume of the elastomer part of the stator remains the same. As a result, an axial deformation of the elastomer part also leads to a radial deformation of the elastomer part, as a result of which the cross section of the passage of the elastomer part in which the rotor is guided is reduced. As a result, in addition to compensating for the stator wear, the pretension between the stator and the rotor can easily be varied, that is to say that Adjusting or adjusting the stator according to the invention can also be used to adapt the pretension between the stator and rotor of an eccentric screw pump to different operating conditions and operating states.

According to the invention, it is provided that the stator-rotor system has an adjusting mechanism for adjusting or adjusting the stator, which comprises two adjusting elements which are coupled to the stator-rotor system and which are variable in relation to one another. In a first working position, the two setting elements are at a first distance from one another and in a second working position, the two setting elements are at a second distance from one another, the first distance being not equal to the second distance. In the second working position, the cross section and the length of the elastomer part of the stator are changed compared to the cross section and the length of the elastomer part in the first working position. The cross section of the elastomer part, in particular the cross section of the internal thread of the elastomer part, is important in relation to the pre-tension formed between the stator and the rotor. In particular, for example, compressing the elastomer part, reducing its length, increases the cross section. At the same time, the inner contour of the stator is reduced, which increases the preload between the stator and rotor. Conversely, stretching the elastomer part, increasing its length, reduces the cross-section. At the same time, the inner contour of the stator increases, which reduces the preload between the stator and rotor.

According to a preferred embodiment there is a mechanical coupling and / or connection between the adjusting mechanism and the stator, in particular there is such a mechanical coupling and / or connection between the adjusting mechanism and the elastomer part of the stator. By changing the relative distance between the two adjusting elements of the adjusting mechanism, the cross section and the length of the elastomer part of the stator are changed.

According to a preferred embodiment, the second distance is smaller than the first distance, the cross section of the elastomer part of the stator being enlarged in the second working position compared to the first working position and the length of the elastomer part of the stator being reduced compared to the first working position. In this embodiment, an approximation of the setting elements causes an enlargement or increase the bias between the rotor and stator of the stator-rotor system. In contrast, a spacing of the adjusting elements from one another results in a reduction in the pretension between the rotor and the stator of the stator-rotor system.

According to an alternative embodiment, the second distance is greater than the first distance, the cross section of the elastomer part of the stator being reduced in the second working position compared to the first working position and the length of the elastomer part of the stator being increased compared to the first working position. In this embodiment, removal of the adjusting elements causes a reduction in the pretension between the rotor and the stator of the stator-rotor system. In contrast, a spacing of the adjusting elements from one another causes an increase or increase in the pretension between the rotor and the stator of the stator-rotor system.

According to a preferred embodiment, it is provided that one of the adjusting elements is arranged in a stationary manner on the stator-rotor system and the other adjusting element is arranged in a variable position on the stator-rotor system. In particular, the first setting element is arranged in a fixed position on the support element or stator jacket and the second setting element is arranged in a variable position on the elastomer part of the stator. According to a preferred embodiment, it is provided that the first setting element is arranged in a fixed position on a flange at a free end of the support element or stator casing and that the second position-variable setting element is arranged on a free end of the elastomer part of the stator.

The relative distance between the two setting elements can be set in different ways. For example, wedge elements can be assigned to each of the two setting elements. The wedge elements are operatively connected to one another, so that a change in the position of one wedge element forces a change in the position of the other wedge element. While the first wedge element assigned to the first stationary adjusting element is displaceable relative to the latter, the second wedge element assigned to the second position-variable adjusting element is fixed in place on the second adjusting element. A movement of the first wedge element, in particular a displacement of the first wedge element relative to the first adjustment element, causes a displacement of the second wedge element and thus a displacement of the second position-variable adjustment element. In particular the displacement movement of the second wedge element is oriented approximately orthogonally to the displacement movement of the first wedge element.

According to a further embodiment, a plurality of wedge rings are provided between the two setting elements. By rotating the wedge rings against each other, the distance can be varied as desired in a range between a minimum distance defined by the wedge rings and a maximum distance.

Alternatively, the use of a spindle with an external thread or a toothed rack can be provided, which is arranged between or on the setting elements in such a way that the second position-variable setting element can be moved in the direction of the first fixed setting element or in the opposite direction from the first fixed setting element. This is possible, for example, in combination with a toggle mechanism. Instead of a spindle, at least one hydraulic or pneumatic hollow cylinder can also be provided for changing the distance between the two setting elements or for adjustment via a plurality of threads.

In addition to the adjustment mechanism comprising two adjustment elements, the invention can in particular comprise a support element, so that the elastomer part of the stator is at least partially covered and supported on an exposed outer end region in which the elastomer part is not enclosed by the support element or stator jacket. Furthermore, a compensating element may be necessary so that at least a large part of the exposed elastomer part is always covered and supported.

According to a preferred embodiment, a support and / or compensation element is arranged between the first fixed setting element and the second position-variable setting element, which at least partially covers and supports an exposed end region of the elastomer part. For example, the supporting and / or compensating element can consist of at least two supporting elements which encompass the elastomer part in a form-fitting manner and are at least partially guided into one another. One of the support elements is arranged on the first fixed setting element and the other support element is arranged on the second position-variable setting element. For example, one of the support elements is designed as a support ring encompassing the end region of the elastomer part and the other support element is designed as a hollow cylinder and on the flange of the support element or stator jacket arranged. The inner diameter of the hollow cylinder is at least slightly larger than the outer diameter of the support ring. The support ring is guided in the hollow cylinder according to the cylinder-piston principle. Support ring and hollow cylinder are arranged on the stator-rotor system in such a way that the hollow cylinder largely encloses the support ring with minimal spacing of the two adjusting elements. At maximum spacing of the two adjusting elements, however, the hollow cylinder encloses only a small part of an area of the support ring facing away from the free end of the elastomer part of the stator. In this way, radial support of the elastomer part is always guaranteed in the end region not enclosed by the support element or stator jacket.

According to a further embodiment, the support elements have approximately the same inside and outside diameter. Each of the support elements has regularly spaced fingers. The support elements are arranged on the stator-rotor system in such a way that the fingers of one support element are guided in the spaces between the fingers of the other support element. With minimal spacing of the two adjusting elements, the fingers of one support element largely fill the gaps between the fingers of the other support element and vice versa. With maximum spacing of the two setting elements, on the other hand, only end regions of the fingers of the one support element engage in the spaces between the end regions of the fingers of the other support element. In this way, radial support of the elastomer part is always guaranteed in the end region not enclosed by the support element or stator jacket.

According to a further embodiment, a spring assembly encompassing the elastomer part, for example a corrugated spring, or a plurality of elements loosely encompassing the elastomer part are used as the supporting and / or compensating element. Alternatively, the support and / or compensation element can also be formed by a material that is introduced internally and / or externally into the elastomer part and / or applied to the elastomer part.

Various other adjustment mechanisms can also be used to adjust the distance between the two setting elements. For example, it is conceivable to vary the distance between the setting elements by means of suitable hydraulically or pneumatically operated setting means or by means of suitable mechanical setting means.

The invention further relates to a method for adjusting or adjusting a stator in a stator-rotor system of an eccentric screw pump, in particular a method for adjusting or adjusting a stator in a previously described stator-rotor system. Here, the relative distance between two adjusting elements arranged on the stator-rotor system is changed in a targeted manner, whereby the cross section and / or the length of the elastomer part can be adjusted in order to adjust it and / or to adapt it to the respective operating conditions.

According to one embodiment of the method, the relative distance between the two adjusting elements is reduced in order to increase the cross section of the elastomer part of the stator and to reduce the length of the elastomer part of the stator, as a result of which the pretension between the stator and the rotor can be increased. If, on the other hand, the relative distance between the two adjusting elements is increased, the cross section of the elastomer part of the stator is reduced, while the length of the elastomer part of the stator is increased, as a result of which the pretension between the stator and the rotor can be reduced.

According to an alternative embodiment of the method, the relative distance between the two adjusting elements is increased in order to reduce the cross section of the elastomer part of the stator and to increase the length of the elastomer part of the stator, the preload between stator and rotor being reduced. If, on the other hand, the relative distance between the two adjusting elements is reduced, the cross section of the elastomer part of the stator increases, while the length of the elastomer part of the stator decreases, the preload between the stator and rotor being increased.

As an alternative or in addition to the features described, the method can comprise one or more features and / or properties of the device described above. Alternatively or additionally, the device can also have individual or multiple features and / or properties of the described method.

According to one embodiment of the invention, automation of the stator adjustment is provided. For this purpose, the adjustment mechanism is coupled to a control system and is controlled and controlled by this. In particular, the control system comprises at least one sensor for determining actual operating parameters of the stator-rotor system and a controller for adjusting the adjustment mechanism. The setting of the adjustment mechanism is determined on the basis of data measured by sensors, the adjustment of the adjustment mechanism being controlled and / or controlled or monitored by the control.

The control mechanism according to the invention establishes a connection between different physical operating parameters of the stator-rotor system and the state of wear of the stator or the pretension between the stator and rotor. For example, a relationship is established between the physical operating parameters pressure, flow rate, speed and / or viscosity and the state of wear of the stator or the pretension between the stator and the rotor. The most direct parameter that combines these relationships is the tension in the elastomer material. This can either be determined directly via a corresponding sensor system in the elastomer material, or indirectly via the reaction force of the elastomer on other components.

With the aid of the control algorithm according to the invention, a correlation is established, for example from pressure, flow, speed and the required preload, and a corresponding adjustment path for adjusting the adjustment mechanism is then determined, which should be suitable for setting the optimal operating point. In particular, the distance to be set between the setting means of the adjustment mechanism is calculated. After automatic adjustment of the adjustment mechanism, the physical operating parameters of the eccentric screw pump are measured again and it is determined from this whether the optimal operating state has been reached. If the measured operating parameters do not correspond to the desired target parameters, an adjustment path is calculated again and the adjustment mechanism is readjusted, in particular the relative distance between the adjustment means of the adjustment mechanism is readjusted. The second position-variable setting element is preferably controlled by the controller in order to change the distance from the first fixed setting element.

As part of the control, the actual operating status of the eccentric screw pump is first queried. Here, at least one physical actual operating parameter relating to the eccentric screw pump and / or at least one physical actual operating parameter relating to the elastomer part of the stator-rotor system and / or at least one physical actual operating parameter of the adjusting mechanism are determined by sensors. Then the sensor-determined actual operating parameters compared with known or desired target operating parameters. The comparison is made in particular on the basis of data stored in the control. If a deviation between the actual operating parameters and the target operating parameters is determined in the comparison, a necessary adjustment of the adjustment mechanism is calculated and this is controlled and adjusted accordingly, which leads to an adjustment or readjustment of the stator, in particular to a change in the cross section and the length of the elastomer part of the stator.

According to a preferred embodiment, after the adjustment of the adjustment mechanism, after a defined period of time, the actual operating state of the eccentric screw pump is queried again and compared with the target operating parameters. The success of the adjustment is checked. If there is still a significant difference between the actual operating parameters and the target operating parameters of the eccentric screw pump, the adjustment mechanism is triggered and adjusted again. If the deviation between the actual operating parameters and the target operating parameters could be sufficiently reduced by adjusting the adjustment mechanism and thus adjusting or adjusting the stator, no further adjustment is made. Instead, the set operating state of the eccentric screw pump is checked again after a defined further period of time by means of the sensor measurements described above.

If, on the other hand, no deviation between the actual operating parameters and the target operating parameters is determined when the actual operating status of the eccentric screw pump is queried for the first time, the actual operating status of the eccentric screw pump is queried again after a defined period of time by measuring the actual operating parameters and again Comparison of the same with the target operating parameters. The stator-rotor system is continuously monitored during operation by regular polling at defined time intervals and can be readjusted and adapted promptly.

According to one embodiment of the invention, the pressure, the speed, the temperature and / or the volume flow of the eccentric screw pump is determined by sensors. Alternatively or additionally, the pretension between the rotor and stator and / or the reaction forces of the elastomer material of the elastomer part are measured. Furthermore, the position of at least one setting element of the sensor Adjustment mechanism and / or the relative distance between two adjustment elements of the adjustment mechanism can be determined.

With the stator-rotor system and the method for adjusting or adjusting the stator of a stator-rotor system, wear and tear of a stator can be compensated for simply, quickly and thus cost-efficiently. Furthermore, the setting or readjustment of the stator according to the invention can also be used to adapt the preload between the stator and rotor of an eccentric screw pump.

This effect is also used to compensate for expansion of the elastomer, for example due to an elevated temperature of the medium being conveyed or the swelling of the elastomer. By deliberately reducing the preload between the stator and rotor, friction losses can be minimized, which in turn can increase energy efficiency enormously. Furthermore, the breakaway torques at the start of the pump can be minimized, i.e. a lower torque is required to overcome static friction and to change into sliding friction.

Adjusting the stator can still be used as a leak valve when the pump is at a standstill. When the pump is at a standstill, the preload is increased, which leads to a seal between the rotor and stator of the eccentric screw pump.

With the aid of the stator-rotor system according to the invention, the efficiency of the pump can in particular be increased, since the backflow of medium can be largely minimized.

The stator is adjusted or adjusted by the interaction of two adjusting elements. A change in the distance between the two adjusting elements causes a deformation of the elastomer and thus a change in the cross section and / or the length of the elastomer part of the stator and thus an adjustment or readjustment of the elastomer part of the stator. The position of the two elements can take place over the entire length of the stator and beyond. For example, the first stationary element can be arranged on the flange of the support element or stator jacket flange at one end of the stator-rotor system and the second stationary element on the opposite free end of the elastomer part of the stator-rotor system.

Figure description

• Figur 1 zeigt eine schematische Teil- Ansicht eines bekannten Stator- Rotor-Systems (Stand der Technik).
• Figur 2 zeigt eine schematische Teil- Ansicht einer ersten Ausführungsform eines erfindungsgemäßem Stator- Rotor- Systems mit Verstellmechanismus.
• Figur 3 zeigt schematisch eine Teil- Ansicht einer weiteren Ausführungsform eines erfindungsgemäßem Stator- Rotor- Systems mit Verstellmechanismus.
• Figur 4 zeigt schematisch eine Teil- Ansicht einer weiteren Ausführungsform eines erfindungsgemäßem Stator- Rotor- Systems mit Verstellmechanismus.
• Figur 5 zeigt einen Stator mit Stützring im Querschnitt.
• Figur 6 zeigt ein weiteres Abstütz- Ausgleichselement einer Ausführungsform des erfindungsgemäßen Stator- Rotor- Systems.
• Figur 7 zeigt ein weiteres Abstütz- Ausgleichselement einer Ausführungsform des erfindungsgemäßen Stator- Rotor- Systems.
• Figuren 8 bis 14 zeigen verschiedene Ausführungsformen von Einstellmechanismen, die im Rahmen der Erfindung Anwendung finden können.

In the following, exemplary embodiments are intended to explain the invention and its advantages with reference to the attached figures. The size relationships of the individual elements to one another in the figures do not always correspond to the real size relationships, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• Figure 1 shows a schematic partial view of a known stator-rotor system (prior art).
• Figure 2 shows a schematic partial view of a first embodiment of a stator-rotor system according to the invention with adjustment mechanism.
• Figure 3 shows schematically a partial view of a further embodiment of a stator-rotor system according to the invention with adjustment mechanism.
• Figure 4 shows schematically a partial view of a further embodiment of a stator-rotor system according to the invention with adjustment mechanism.
• Figure 5 shows a stator with support ring in cross section.
• Figure 6 shows a further support compensation element of an embodiment of the stator-rotor system according to the invention.
• Figure 7 shows a further support compensation element of an embodiment of the stator-rotor system according to the invention.
• Figures 8 to 14 show different embodiments of adjustment mechanisms that can be used within the scope of the invention.

Identical reference numerals are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numerals are shown in the individual figures which are necessary for the description of the respective figure. The illustrated embodiments merely represent examples of how the device according to the invention or the method according to the invention can be designed and do not constitute a final limitation.

Figure 1 shows a schematic partial view of a known stator-rotor system 1 for an eccentric screw pump. Such a system 1 includes one in the Rule metallic, single-start spiral rotor (not shown) and a stator 3 with a two-start thread. When the eccentric screw pump is operated, the rotor performs an eccentric rotary movement about the longitudinal axis X3 of the stator with its figure axis. The stator 3 comprises an elastomer part 4 and a stator jacket 5 as a supporting element, there being no fixed connection between the elastomer part 4 and the stator jacket 5.

Figure 2 shows a schematic partial view of a first embodiment of a stator-rotor system 10, 10a according to the invention with adjusting mechanism 12. The adjusting mechanism 12 comprises a first fixed adjusting element 13 and a second position-variable adjusting element 14. A change in the distance between the two adjusting elements 13, 14 causes one Deformation of the elastomer and thus a change in the cross section and / or the length of the elastomer part 4 of the stator 3 and thus an adjustment or readjustment of the elastomer part 4 of the stator 3. In particular, a flange 23 on the stator casing 5 serves as a fixed adjusting element 13 and one at the free end 8 of the elastomer part 4 arranged actuating element 24 serves as a variable position adjusting element 14.

Figures 3 and 4 show schematic partial views of further embodiments of a stator-rotor system 10b, 10c according to the invention with adjustment mechanism 12.

The change in the distance of the two adjusting elements 13, 14 from one another causes a deformation of the elastomer and thus a change in the cross section and / or the length of the elastomer part 4 of the stator 3. However, the length of an end region 9 of the elastomer part 4 protruding from the stator jacket 5 also changes .

The end region 9 of the elastomer part 4 protruding from the stator jacket 5 is preferably at least partially covered and supported by a support element which at least partially covers and supports the elastomer part 4 of the stator 3 in the exposed end region 9 in which the elastomer part 4 is not enclosed by the stator jacket 5. In order to be able to compensate for the change in length of the elastomer part 4, a compensating element is also necessary so that at least a large part of the exposed elastomer part 4 is always covered and supported.

According to the in Figure 3 In the embodiment shown, two elements 30, 31 which enclose the elastomer part 4 in a form-fitting manner and are at least partially guided into one another are provided, in particular a support ring 30 * and a hollow cylinder 31 *, which support the elastomer part 4 according to the cylinder-piston principle of length changes. One of the elements, in particular the support ring 30 *, is arranged and fastened on the position-variable adjusting element 14 and the other element, in particular the hollow cylinder 31 *, is arranged and fastened on the stationary adjusting element 13. When the position-variable adjusting element 14 approaches the stationary adjusting element 13, the support ring 30 * is pushed further into the hollow cylinder 31 *. If the position-variable adjusting element 14 is spaced further apart from the stationary adjusting element 13, the support ring 30 * is at least partially pulled out of the hollow cylinder 31 *. In particular, both elements 30, 31 jointly support the exposed end region 9 and the length compensation of the elastomer part 4, that is to say each of the two elements 30, 31 serves both as a support element and as a compensation element.

An element 30, in particular a support ring 30 *, which positively encompasses the elastomer part 4 can be attached, for example, to the thickened free end 8 of the elastomer part 4 and is shown in FIG Figure 13 shown. The elastomer part 4 is arranged in the stator jacket 5. Subsequently, an element 30 which engages around the elastomer part 4 in a form-fitting manner is arranged in the form of a support ring 30 * in the region of the free end 8 of the elastomer part 4 and screwed together after assembly. In particular, the screw connection 40 takes place in the region of the thickening of the free end 8 of the elastomer part 4.

Figure 5 shows the structure of a support ring 30 arranged around the elastomer part 4 of the stator 3. This has an overlap and is fastened in the overlap region by means of a screw connection 40 on the elastomer part 4.

Figure 6 shows a further support compensation system also comprising two elements 32, 33 which encompass the elastomer part 4 in a form-fitting manner and are at least partially guided into one another. The elements 32, 33 each have regularly spaced fingers 34. The two elements 32, 33 are arranged such that the fingers 34a of the first element 32 engage in the spaces between the fingers 34b of the second element 33. By moving the elements 32, 33 against each other, changes in length of the elastomer part 4 can thus be compensated for, while at the same time the support of the elastomer part 4 is ensured. This means that in this embodiment, too, each of the two elements 32, 33 serves both as a supporting element and as a compensating element.

Figure 4 shows an embodiment of a stator-rotor system 10c according to the invention with an adjustment mechanism 12 with a support compensating element 35 between the first fixed adjusting element 13, in particular between the stator jacket flange 23, and the second position-variable adjusting element 14, in particular the actuating element 24. For example, loose elements which encompass the elastomer part 4 of the stator 3 can serve as a supporting compensating element 35, between the adjusting elements 13, 14 lie and thus cover a large part of the exposed outer surface area of the elastomer part 4. According to a further embodiment, a spring assembly, for example, a spring assembly encompassing the elastomer part 4 of the stator 3, can be provided as the support compensating element 35 Figure 7 wave spring 37 shown.

According to a further embodiment, not shown, the elastomer part 4 can also be supported internally and / or externally at the exposed locations by a material introduced into the elastomer part 4 or applied to the elastomer part 4, for example an elastomer-fiber composite can be used for this. Since in this case the compensating function is also effected by this material, the length of the elastomer part 4 supported in this way along the longitudinal axis X3 of the stator (cf. Figure 1 ) be chosen accordingly so that the area of the elastomer part 4 which is exposed at any given time is always adequately supported.

Figures 8 to 14 show various embodiments of adjustment mechanisms 12 which can be used within the scope of the invention.

Figure 8 represents an adjustment mechanism 12a in the form of a wedge mechanism, in which a first wedge element 50 is arranged on the first fixed adjusting element 13 and a second wedge element 54 is arranged on the second position-variable adjusting element 14. The first setting element 13 further comprises a spindle 52 with an external thread fastened to the first wedge element 50, which is guided by a nut 51 with a corresponding internal thread. By rotating the spindle 52 about the longitudinal axis X52, the first wedge element 50 is moved in a first direction of movement B1. The movement of the first wedge element 50 is transmitted to the second wedge element 54 of the second adjusting element 14 which is operatively connected to the first wedge element 50. This leads to a movement of the second setting element 14 in a second movement direction B2, which is essentially orthogonal to the first movement direction B1 of the first wedge element 50. The interaction of the wedge elements 50, 54 of the two adjusting elements 13, 14 brings about a change in the distance between the two adjusting elements 13, 14 and thus one Deformation of the elastomer, in particular a change in the cross section and / or a change in the length of the elastomer part 4.

Figure 9 shows an adjustment mechanism 12b in the form of an adjustment by means of a spindle 60. The spindle 60 has an external thread 62. The spindle 60 is rotatably arranged and mounted on the flange 23 arranged fixed on the stator jacket 5. In particular, the spindle 60 is mounted in a stationary manner on the flange 23, ie rotation of the spindle 60 does not change the position of the spindle 60 relative to the flange 23. The spindle 60 has an adjustment shoulder 66. This can be designed, for example, as a clutch for a motor or as a starting point for manual adjustment of the spindle 60.

According to an embodiment of the invention, a plurality of spindles (not shown) can be arranged around the outer circumference of the stator 3. A first driven spindle 60 can be mechanically coupled to the other non-driven spindles (not shown) via a gear 64 and a ring gear 65 or other suitable coupling means such that all spindles can be adjusted together.

At the free end of the elastomer part 4 of the stator 3 (compare Figure 1 ) a second position-variable setting element 14 is arranged. A support compensating element 35 is provided between the second position-variable setting element 14 and the flange 23 serving as the first fixed setting element 13, as is the case, for example, in connection with FIGS Figures 3 to 6 has been described.

The second position-variable setting element 14 has a bearing for the spindle 60 with an internal thread (not shown), in which the spindle 60 is rotatably mounted, so that a rotation R of the spindle 60 about its longitudinal axis X60, a movement of the second position-variable setting element 14 effected in a direction of movement B3.

Figure 10 represents part of an adjusting mechanism 12c in the form of a toggle lever 70. A spindle 72 or rack 73 with an external thread 74 is assigned to an adjusting element 75 so as to be rotatable. Two adjusting elements 77 are arranged on the spindle 72 via movably mounted connecting elements 76. One of the adjusting elements 77a is fixed in place and forms the first fixed adjusting element 13. The other adjusting element 77b is variable in position and forms the second variable adjusting element 14. By actuating the adjusting element 75, for example by Rotation R, the spindle 72 is moved and in particular moved in the direction of movement B4. This movement is transmitted via the movable connecting elements 76 to the adjusting elements 77, which are thereby moved closer to one another or moved apart, in particular the variable-position adjusting element 77b being moved relative to the fixed adjusting element 77a.

Figure 11 shows an adjustment mechanism 12d in the form of an adjustment by means of wedge rings 80, 82. The adjustment mechanism 12d is constructed, for example, from two outer wedge rings 80a, 80b and two inner wedge rings 82a, 82b and is seated at the free end 8 on the elastomer part 4 of the stator. The outer wedge ring 80b is arranged on a fixed part 13, for example on the flange 23 of the stator casing (not shown). The variable outer setting element 14 is assigned to the opposite outer wedge ring 80a. The two inner wedge rings 82a, 82b are seated on the widened free end 8 of the elastomer part 4 of the stator and are fixed thereon. By rotating the wedge rings 80a, 80b, 82a, 82b, their spacing from one another is set and thus the relative distance between the flange 23 of the stator casing and the free end 8 of the elastomer part 4 of the stator is varied.

Figure 12 represents an adjusting mechanism 12e by means of a hydraulic or pneumatic hollow cylinder 90. Here, the second position-variable adjusting element 14 is in turn arranged on the widened free end 8 of the elastomer part 4 of the stator 3. The flange 23 on the stator casing 5 represents the fixed setting element 13 and is increased in its outer regions in the direction of the free end 8 of the elastomer part 4 by an attached ring or the like. At least one hydraulic or pneumatic hollow cylinder is arranged on the second position-variable setting element 14. By actuating the hollow cylinder, in particular by filling or removing a suitable fluid, the second position-variable adjusting element 14 can be moved in the direction of the first stationary adjusting element 13 or in the opposite direction. The change in distance between the two adjusting elements 13, 14 causes the desired deformation of the elastomer part 4 and thus an adjustment or readjustment of the elastomer part 4 of the stator 3. Analogously to Figures 2 to 4 a support compensation element 35 is in turn provided between the second position-variable setting element 14 and the flange 23 serving as the first fixed setting element 13

Figure 13 shows an adjustment mechanism 12f which achieves the adjustment of the relative distance of the adjustment elements 13, 14 from one another with the aid of threads. The fixed adjusting element 13 is operatively connected to the position-variable adjusting element 14 via a thread arrangement. The position-variable adjusting element 14 is designed as an adjusting ring 93 and is placed on the flange of the elastomer part 4 with a thread. The adjusting ring 93 also receives a collar 95, which is fixed via a clamping ring 97. A fixed fastening ring is arranged at the free end 8 of the elastomer part 4. A drive gear 94 and a gear 96 with an internal thread are assigned to the fastening ring 92. The gear 96 with an internal thread in turn engages the position-variable adjusting element 14 or adjusting ring 93. The twisting of the threads of the gear wheels 94, 96 relative to one another causes the position-variable adjusting element 14 or adjusting ring 93 to move along the longitudinal axis X3 of the stator (not shown) or the elastomer part 4.

Fig. 14 shows an adjustment mechanism 12g, which is designed as a medium-operated adjustment system, in particular a hydraulic or pneumatic adjustment system, using a membrane 45. The principle of the medium-operated adjustment mechanism 12g is a modification of the idea of the adjustment by means of a hydraulic cylinder 46 according to Figure 12 . The bias between stator 3 and rotor (not shown) is set as a function of a medium pressure on the membrane 45.

The hydraulic cylinder 46 comprises a fixed cylinder part 47 and a movably mounted cylinder part 48, on which the membrane 45 is arranged in such a way that it separates the hydraulic fluid H from the medium pumped by the eccentric screw pump. The hydraulic cylinder 46 is arranged at the free end 8 of the elastomer part 4 of the stator 3, in particular the movably mounted cylinder part 48 is fastened to the elastomer flange and the stationary fixed cylinder part 47 is arranged and fixed on the stator jacket 5.

Instead of positioning the hydraulic cylinder 46 externally via a unit and a logic / control system, the medium pressure of the eccentric screw pump is used. This simplifies the system and significantly reduces costs. The necessary separation between hydraulic fluid H and medium is realized in the illustrated embodiment by the membrane 45. When the pump pressure increases, the pressure is transferred to the hydraulic fluid H via the membrane 45, which leads to an adjustment of the hydraulic cylinder 46. In particular, a pressure transmission D causes the movably mounted cylinder part 48 to be displaced with respect to the fixedly fixed cylinder part 47. The hydraulic cylinder is reset 46 in the case of a reduction in pressure takes place via the spring force of the elastomer of the elastomer part 4 and / or through additional components. As a result of this interaction, the elastomer of the elastomer part 4 is compressed to such an extent that, depending on the pump pressure, an optimal preload is established between the rotor (not shown) and the stator 3.

The end region 9 of the elastomer part 4 protruding from the stator jacket 5 is also at least partially enclosed in this exemplary embodiment by an encompassing (support) element 30 which supports the elastomer part 4 of the stator 3 in the exposed end region 9, in which the elastomer part 4 is not the stator jacket 5 is enclosed, at least partially covered and supported. Furthermore, there is a compensating element 36 which can compensate for the change in length of the elastomer part 4 of the stator-rotor system of the eccentric screw pump in relation to a fixed flange 20 of the eccentric screw pump.

According to a further embodiment, not shown, it is provided to distribute a plurality of hydraulic cylinders 46 on the circumference of the free end 8 of the elastomer part 4 of the stator 3 and to operate them according to the principle described.

According to a further embodiment, not shown, it is provided that the end face of the elastomer part 4 is used as a piston, on which the medium pressure of the pumped medium acts directly.

The invention has been described with reference to a preferred embodiment. However, it is conceivable for a person skilled in the art that modifications or changes of the invention can be made without leaving the scope of the following claims.

Reference list

1

Stator-rotor system

3rd

stator

4th

Elastomer part

5

Stator jacket

8th

free end

9

End area

10th

Stator-rotor system

12th

Adjustment mechanism

13

first fixed setting element

14

second position variable setting element

23

flange

24th

Actuator

30th

comprehensive (compensation) element

30 *

Support ring

31

encompassing element

31 *

Hollow cylinder

32

encompassing element with regularly spaced fingers

33

encompassing element with regularly spaced fingers

34

finger

35

Support compensating element

36

Compensating element

37

Corrugated spring

40

Screw connection

45

membrane

46

Hydraulic cylinder

47

fixed cylinder part

48

movably mounted cylinder part

50

first wedge element

51

mother

52

spindle

54

second wedge element

60

spindle

62

External thread

64

gear

65

Sprocket

66

Adjustment approach

70

Toggle lever

72

spindle

73

Rack

74

External thread

75

storage

76

Fastener

77

Actuator

80

Wedge ring

82

Wedge ring

90

Hollow cylinder

92

Mounting ring

93

Adjustment ring

94

Drive gear

95

Federation

96

Gear with internal thread

97

Clamping ring

B

Direction of movement

H

Hydraulic fluid

R

rotation

Ü

Overlap area

X3

Longitudinal axis

Claims (13)

1. A stator-rotor system (10) of an eccentric screw pump comprising a rotor with a rotor screw and a stator (3) with an internal thread, the stator (3) comprising a support element (5) and an elastomer part (4), wherein the support element (5) surrounds the elastomer part (4) in sections around the whole circumference, wherein the stator-rotor system (10) comprises an adjusting mechanism (12) for adjusting the stator (3), the adjusting mechanism (12) comprising at least two adjustment elements (13, 14) coupled to the stator-rotor system (10), wherein the two adjustment elements (13, 14) are distance-variable relative to one another, wherein the two adjustment elements (13, 14) have a first distance from one another in a first working position and wherein the two adjustment elements (13, 14) have a second distance from one another in a second working position, wherein the first distance is not equal to the second distance, wherein in the second working position the cross-section and the length of the elastomer part (4) of the stator (3) are changed compared to the cross-section and the length of the elastomer part (4) in the first working position, wherein for the adjustment or readjustment of a stator (3), the relative distance between the two adjustment elements (13, 14) can be adjusted in order to adapt the cross-section and the length of the elastomer part (4) of the stator (3) to given operating conditions, characterised in that the relative distance between the two adjustment elements (13, 14) can be reduced in order to reduce the length of the elastomer part (4) of the stator (3), to increase the cross-section of the elastomer part (4) of the stator (3), to reduce an inner contour of the stator (3) and to increase pretensioning between the rotor and the stator (3), or that the relative distance between the two adjustment elements (13, 14) can be increased in order to increase a length of the elastomer part (4) of the stator (3), to reduce a cross-section of the elastomer part (4) of the stator (3), to increase an inner contour of the stator (3) and to reduce pretensioning between the rotor and stator (3).
2. The stator-rotor system (10) according to claim 1, wherein a mechanical coupling and/or connection is present between the adjusting mechanism (12) and the stator (3), wherein a change in the cross-section and the length of the elastomer part (4) of the stator can be brought about by a change in the relative distance between the two adjustment elements (13, 14).
3. The stator-rotor system (10) according to claim 1 or 2, wherein the second distance is smaller than the first distance, wherein in the second working position the cross-section of the elastomer part (4) of the stator (3) is enlarged compared to the first working position and the length of the elastomer part (4) of the stator (3) is reduced or wherein the second distance is greater than the first distance, wherein in the second working position the cross-section of the elastomer (4) of the stator (3) is reduced compared to the first working position and the length of the elastomer part (4) of the stator (3) is enlarged compared to the first working position.
4. The stator-rotor system (10) according to any one of claims 1 to 3, wherein the one first adjustment element (13) is arranged stationary on the stator-rotor system (10) and wherein the other second adjustment element (14) is arranged position-variable on the stator-rotor system (10).
5. The stator-rotor system (10) according to any one of claims 1 to 4, wherein the first adjustment element (13) is arranged stationary on the support element (5) and wherein the second adjustment element (14) is arranged position-variable on the elastomer part (4).
6. The stator-rotor system (10) according to claim 5, wherein the first adjustment element (13) is arranged stationary on a flange (23) at a free end of the support element (5) and wherein the second position-variable adjustment element (14) is arranged at a free end (8) of the elastomer part (4) .
7. The stator-rotor system (10) according to any one of the preceding claims, wherein the adjusting mechanism (12) comprises wedge elements (50, 54) or wedge rings (80, 82) for changing the distance between the two adjustment elements (13, 14).
8. The stator-rotor system (10) according to any one of claims 1 to 6, wherein the adjusting mechanism (12) comprises a spindle adjustment for changing the distance between the two adjustment elements (13, 14) or wherein the adjusting mechanism (12) comprises an adjustment by means of a toggle lever mechanism (70) for changing the distance between the two adjustment elements (13, 14) or wherein the adjusting mechanism (12) comprises an adjustment by means of a hydraulic or pneumatic hollow cylinder (90) for changing the distance between the two adjustment elements (13, 14) or wherein the adjusting mechanism (12) comprises an adjustment by means of threads (94, 96) for changing the distance between the two adjustment elements (13, 14).
9. The stator-rotor system (10) according to any one of the preceding claims, wherein a supporting and/or compensating element (35) is arranged between the first stationary adjustment element (13) and the second position-variable adjustment element (14), said supporting and/or compensating element at least partially covering and supporting an exposed end region (9) of the elastomer part (4) .
10. The stator-rotor system (10) according to claim 9, wherein the supporting and/or compensating element (35) comprises at least two support elements (30, 31) encompassing the elastomer part (4) in a form-fit manner and at least partially guided into one another, wherein one of the support elements (30, 31) is arranged on the first stationary adjustment element (13) and the other of the support elements (14, 13) is arranged on the second position-variable adjustment element (14), in particular wherein the supporting and/or compensating element (35) comprises a support ring (30*) and a hollow cylinder (31*), wherein the support ring (30*) is guided in the hollow cylinder (31*) according to the cylinder-piston principle or wherein the at least two elements (32, 33) each comprise fingers (34a, 34b) spaced apart at regular intervals, which are guided into one another, wherein the fingers (34a) of the one element (32) are guided into intermediate spaces between the fingers (34b) of the other element (33).
11. The stator-rotor system (10) according to claim 9, wherein the supporting and/or compensating element (35) is formed from a spring assembly encompassing the elastomer part (4) or wherein the supporting and/or compensating element (35) is formed from an undulating spring (37) or wherein the supporting and/or compensating element (35) is formed from a plurality of elements loosely encompassing the elastomer part (4) or wherein the supporting and/or compensating element (35) is formed by a material introduced internally and/or externally into the elastomer part (4) and/or deposited on the elastomer part (4).
12. A method for adjusting a stator (3) in a stator-rotor system (10) of an eccentric screw pump comprising a rotor with a rotor screw and a stator (3) with an internal thread, the stator (3) comprising a support element (5) and an elastomer part (4), wherein the support element (5) and the elastomer part (4) are separate parts and wherein the support element (5) surrounds the elastomer part (4) in sections, wherein the stator-rotor system (10) comprises an adjusting mechanism for adjusting the stator (3), which adjusting mechanism comprises at least two adjustment elements (13, 14), wherein the relative distance between the two adjustment elements (13, 14) is adjusted in order to adjust the cross-section and the length of the elastomer part (4) of the stator (3) and/or to adapt the latter to given operating conditions, wherein for the adjustment or readjustment of a stator (3), the relative distance between the two adjustment elements (13, 14) can be adjusted in order to adapt the cross-section and the length of the elastomer part (4) of the stator (3) to given operating conditions characterised in that the relative distance between the two adjustment elements (13, 14) is reduced in order to reduce the length of the elastomer part (4) of the stator (3), to increase a cross-section of the elastomer part (4) of the stator (3), to reduce an inner contour of the stator (3) and to increase pretensioning between the rotor and the stator (3), or that the relative distance between the two adjustment elements (13, 14) is increased in order to increase a length of the elastomer part (4) of the stator (3), to reduce a cross-section of the elastomer part (4) of the stator (3), to increase an inner contour of the stator (3) and to reduce pretensioning between the rotor and stator (3).
13. The method according to claim 12, wherein the relative distance between the two adjustment elements (13, 14) is reduced in order to reduce the cross-section of the elastomer part (4) of the stator (3) and to increase the length of the elastomer part (4) of the stator (3) or wherein the relative distance between the two adjustment elements (13, 14) is increased in order to increase the cross-section of the elastomer part (4) of the stator (3) and to reduce the length of the elastomer part (4) of the stator (3).

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