Stator-Rotor System And Method For Adjusting A Stator In A Stator-Rotor System

Abstract

A stator-rotor system of an eccentric screw pump including a rotor with a rotor screw and a stator with an internal thread. The stator includes a support element and an elastomer part. The support element surrounds the elastomer part in sections around the whole circumference. The stator-rotor system includes a mechanism for adjusting the stator, having two adjustment elements arranged on the stator-rotor system, which are distance-variable relative to one another. In a first working position the two adjustment elements have a first distance from one another and in a second working position, a second distance. The cross-section and the length of the elastomer part of the stator in the second working position are changed compared to the cross-section and the length of the elastomer part in the first working position.

Claims

1. A stator-rotor system of an eccentric screw pump comprising a rotor with a rotor screw and a stator with an internal thread, the stator comprising a support element and an elastomer part, wherein the support element surrounds the elastomer part in sections around the whole circumference, characterised in that the stator-rotor system comprises an adjusting mechanism for adjusting the stator, the adjusting mechanism comprising at least two adjustment elements coupled to the stator-rotor system, wherein the two adjustment elements are distance-variable relative to one another, wherein the two adjustment elements have a first distance from one another in a first working position and wherein the two adjustment elements 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 of the stator are changed compared to the cross-section and the length of the elastomer part in the first working position.

2. The stator-rotor system according to claim 1, wherein a mechanical coupling and/or connection is present between the adjusting mechanism and the stator, wherein a change in the cross-section and the length of the elastomer part of the stator can be brought about by a change in the relative distance between the two adjustment elements.

3. The stator-rotor system according to claim 1, wherein the second distance is smaller than the first distance, wherein in the second working position the cross-section of the elastomer part of the stator is enlarged compared to the first working position and the length of the elastomer part of the stator 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 of the stator is reduced compared to the first working position and the length of the elastomer part of the stator is enlarged compared to the first working position.

4. The stator-rotor system according to claim 1, wherein the one first adjustment element is arranged stationary on the stator-rotor system and wherein the other second adjustment element is arranged position-variable on the stator-rotor system.

5. The stator-rotor system according to claim 1, wherein the first adjustment element is arranged stationary on the support element and wherein the second adjustment element is arranged position-variable on the elastomer part.

6. The stator-rotor system according to claim 5, wherein the first adjustment element is arranged stationary on a flange at a free end of the support element and wherein the second position-variable adjustment element is arranged at a free end of the elastomer part.

7. Stator-rotor system according to claim 1, wherein the adjusting mechanism comprises wedge elements or wedge rings for changing the distance between the two adjustment elements.

8. The stator-rotor system according to claim 1, wherein the adjusting mechanism comprises a spindle adjustment for changing the distance between the two adjustment elements or wherein the adjusting mechanism comprises an adjustment by means of a toggle lever mechanism for changing the distance between the two adjustment elements or wherein the adjusting mechanism comprises an adjustment by means of a hydraulic or pneumatic hollow cylinder for changing the distance between the two adjustment elements or wherein the adjusting mechanism comprises an adjustment by means of threads for changing the distance between the two adjustment elements.

9. The stator-rotor system according to claim 1, wherein a supporting and/or compensating element is arranged between the first stationary adjustment element and the second position-variable adjustment element, said supporting and/or compensating element at least partially covering and supporting an exposed end region of the elastomer part.

10. The stator-rotor system according to claim 9, wherein the supporting and/or compensating element comprises at least two support elements encompassing the elastomer part in a form-fit manner and at least partially guided into one another, wherein one of the support elements is arranged on the first stationary adjustment element and the other of the support elements is arranged on the second position-variable adjustment element, in particular wherein the supporting and/or compensating element comprises a support ring and a hollow cylinder, wherein the support ring is guided in the hollow cylinder according to the cylinder-piston principle or wherein the at least two elements each comprise fingers spaced apart at regular intervals, which are guided into one another, wherein the fingers of the one element are guided into intermediate spaces between the fingers of the other element.

11. The stator-rotor system according to claim 9, wherein the supporting and/or compensating element is formed from a spring assembly encompassing the elastomer part or wherein the supporting and/or compensating element is formed from an undulating spring or wherein the supporting and/or compensating element is formed from a plurality of elements loosely encompassing the elastomer part or wherein the supporting and/or compensating element is formed by a material introduced internally and/or externally into the elastomer part and/or deposited on the elastomer part.

12. A method for adjusting a stator in a stator-rotor system of an eccentric screw pump comprising a rotor with a rotor screw and a stator with an internal thread, the stator comprising a support element and an elastomer part, wherein the support element and the elastomer part are separate parts and wherein the support element surrounds the elastomer part in sections, characterised in that the stator-rotor system comprises an adjusting mechanism for adjusting the stator, which adjusting mechanism comprises at least two adjustment elements, wherein the relative distance between the two adjustment elements is adjusted in order to adjust the cross-section and the length of the elastomer part of the stator and/or to adapt the latter to given operating conditions.

13. The method according to claim 12 for readjusting a stator in a stator-rotor system, wherein the relative distance between the two adjustment elements is adjusted in order to adapt the cross-section and the length of the elastomer part of the stator to given operating conditions.

14. The method according to claim 12, wherein the relative distance between the two adjustment 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 or wherein the relative distance between the two adjustment 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.

15. The method according to claim 12, wherein the relative distance between the two adjustment elements is reduced 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 or wherein the relative distance between the two adjustment elements is increased 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.

16. The stator-rotor system according to claim 2, wherein the second distance is smaller than the first distance, wherein in the second working position the cross-section of the elastomer part of the stator is enlarged compared to the first working position and the length of the elastomer part of the stator 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 of the stator is reduced compared to the first working position and the length of the elastomer part of the stator is enlarged compared to the first working position.

17. The method according to claim 13, wherein the relative distance between the two adjustment 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 or wherein the relative distance between the two adjustment 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.

18. The method according to claim 13, wherein the relative distance between the two adjustment elements is reduced 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 or wherein the relative distance between the two adjustment elements is increased 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Examples of embodiment of the invention and its advantages are explained in greater detail below with the aid of the appended figures. The size ratios of the individual elements with respect to one another in the figures do not always correspond to the actual size ratios, since some forms are represented simplified and other forms magnified compared to other elements for the sake of better clarity.

[0052] FIG. 1 shows a diagrammatic partial view of a known stator-rotor system (prior art).

[0053] FIG. 2 shows a diagrammatic partial view of a first embodiment of a stator-rotor system according to the invention with an adjusting mechanism.

[0054] FIG. 3 shows diagrammatically a partial view of a further embodiment of a stator-rotor system according to the invention with an adjusting mechanism.

[0055] FIG. 4 shows diagrammatically a partial view of a further embodiment of a stator-rotor system according to the invention with an adjusting mechanism.

[0056] FIG. 5 shows a stator with a support ring in cross-section.

[0057] FIG. 6 shows a further supporting/compensating element of an embodiment of the stator-rotor system according to the invention.

[0058] FIG. 7 shows a further supporting/compensating element of an embodiment of the stator-rotor system according to the invention.

[0059] FIGS. 8 to 14 show various embodiments of adjusting mechanisms which can be used within the scope of the invention.

DETAILED DESCRIPTION

[0060] Identical reference numbers are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numbers that are required for the description of the given figure are represented in the individual figures. The represented embodiments only represent examples as to how the device according to the invention or the method according to the invention can be constituted and do not represent a conclusive limitation.

[0061] FIG. 1 shows a diagrammatic partial view of a known stator-rotor system 1 for an eccentric screw pump. Such a system 1 comprises a usually metallic, single-lead helical rotor (not represented) and a stator 3 with a double-lead thread. During the operation of the eccentric screw pump, the rotor performs with its figure axis an eccentric rotary motion about stator longitudinal axis X3. Stator 3 comprises an elastomer part 4 and a stator casing 5 as a support element, wherein there is no fixed connection between elastomer part 4 and stator casing 5.

[0062] FIG. 2 shows a diagrammatic partial view of a first embodiment of a stator-rotor system 10, 10a according to the invention with adjusting mechanism 12. Adjusting mechanism 12 comprises a first stationary adjustment element 13 and a second position-variable adjustment element 14. A change in the distance of the two adjustment elements 13, 14 from one another brings about a deformation of the elastomer and therefore a change in the cross-section and/or the length of the elastomer part 4 of stator 3 and therefore an adjustment or readjustment of elastomer part 4 of stator 3. In particular, a flange 23 on stator casing 5 serves as a stationary adjustment element 13 and actuation element 24 arranged at free end 8 of elastomer part 4 serves as a position-variable adjustment element 14. The change in position of position-variable adjustment element 14 is brought about in particular by moving the latter parallel to stator longitudinal axis X3, as a result of which the distance from stationary adjustment element 13 is changed.

[0063] FIGS. 3 and 4 show diagrammatic partial views of further embodiments of a stator-rotor system 10b, 10c according to the invention with adjusting mechanism 12.

[0064] The change in the distance of the two adjustment elements 13, 14 from one another brings about a deformation of the elastomer and therefore a change in the cross-section and/or the length of elastomer part 4 of stator 3. However, the length of an end region 9 of elastomer part 4 projecting out of stator casing 5 is thus also changed.

[0065] End region 9 of elastomer part 4 projecting out of stator casing 5 is preferably at least partially covered and supported by a supporting element, which at least partially covers and supports elastomer part 4 of stator 3 in exposed end region 9 in which elastomer part 4 is not surrounded by stator casing 5. In order to compensate for the change in length of elastomer part 4, the compensating element is also required in order that at least a major part of exposed elastomer part 4 is always covered and supported.

[0066] According to the embodiment represented in FIG. 3, two elements 30, 31 encompassing elastomer part 4 in a form-fit manner and guided at least partially into one another are provided, in particular a support ring 30* and a hollow cylinder 31*, which provide a support of elastomer part 4 taking account of the changes in length according to the cylinder-piston principle. One of the elements, in particular support ring 30*, is arranged and fixed on position-variable adjustment element 14 and the other element, in particular hollow cylinder 31*, is arranged and fixed on stationary adjustment element 13. When position-variable adjustment element 14 approaches stationary adjustment element 13, support ring 30* is pushed farther into hollow cylinder 31*. When position-variable adjustment element 14 is moved farther away from stationary adjustment elements 13, support ring 30* is withdrawn at least partially from hollow cylinder 31*. In particular, the two elements 30, 31 together bring about the supporting of exposed end region 9 and the length compensation of elastomer part 4, i.e. each of the two elements 30, 31 serves both as a supporting element and also as a compensating element.

[0067] The fixing of an element 30, in particular a support ring 30*, encompassing the elastomer part 4 in a form-fit manner, can take place for example on thickened free end 8 of elastomer part 4 and is represented in FIG. 13. Elastomer part 4 is arranged in this stator casing 5. An element 30 in the form of a support ring 30* encompassing elastomer part 4 in a form-fit manner is then arranged in the region of free end 8 of elastomer part 4 and screwed down after fitting. Screwing 40 takes place in particular in the region of the thickened portion of free end 8 of elastomer part 4.

[0068] FIG. 5 shows the structure of a support ring 30 arranged around elastomer part 4 of stator 3. Said support ring comprises an overlap and is fixed to elastomer part 4 by means of screwing 40 in the overlap region.

[0069] FIG. 6 shows a further supporting/compensating system also comprising two elements 32, 33 encompassing elastomer part 4 in a form-fit manner and guided at least partially into one another. Elements 32, 33 each comprise fingers 34 spaced apart at regular intervals. The two elements 32, 33 are arranged in such a way that fingers 34a of first element 32 engage in the intermediate spaces between fingers 34b of second element 33. By displacing elements 32, 33 relative to one another, length changes in elastomer part 4 can thus be compensated for, whilst at the same time the supporting of elastomer part 4 is ensured. This means that, also with this embodiment, each of the two elements 32, 33 serves both as a supporting element and also as a compensating element.

[0070] FIG. 4 shows an embodiment of a stator-rotor system 10c according to the invention with adjusting mechanism 12 with a supporting/compensating element 35 between first stationary adjustment element 13, in particular between stator casing flange 23, and a second position-variable adjustment element 14, in particular actuation element 24. Loose elements, for example, can be used as supporting/compensating element 35, which loose elements encompass elastomer part 4 of stator 3, lie between adjustment elements 13, 14 and therefore cover a major part of the exposed outer casing surface of elastomer part 4. According to a further embodiment, a spring assembly encompassing elastomer part 4 of stator 3 can be provided as a supporting/compensating element 35, for example an undulating spring 37 represented in FIG. 7.

[0071] According to a further embodiment not represented, elastomer part 4 can be supported at the exposed points also internally and/or externally by a material introduced into elastomer part 4 or deposited on elastomer part 4, an elastomer-fibre composite, for example, being used for this purpose. Since, in this case, the compensation function is also brought about by this material, the length of elastomer part 4 thus supported along stator longitudinal axis X3 (see FIG. 1) must correspondingly be selected such that the region of elastomer part 4 exposed at any given time is always sufficiently supported.

[0072] FIGS. 8 to 14 show various embodiments of adjusting mechanisms 12 which can be used within the scope of the invention.

[0073] FIG. 8 represents an adjusting mechanism 12a in the form of a wedge mechanism, wherein a first wedge element 50 is arranged on first stationary adjustment element 13 and a second wedge element 54 is arranged on second position-variable adjustment element 14. First adjustment element 13 also comprises a spindle 52 with an external thread, said spindle being fastened to first wedge element 50 and guided through a nut 51 with a corresponding internal thread. By rotating spindle 52 about spindle longitudinal axis X52, first wedge element 50 is moved in a first movement direction B1. The movement of first wedge element 50 is transmitted to second wedge element 54 of second adjustment element 14, said second wedge element being in an operative connection with first wedge element 50. This leads to a movement of second adjustment element 14 in second movement direction B2, which is essentially orthogonal to first movement direction B1 of first wedge element 50. The interaction of wedge elements 50, 54 of the two adjustment elements 13, 14 brings about a change in the distance of the two adjustment elements 13, 14 from one another and thus a deformation of the elastomer, in particular a change in the cross-section and/or a change in the length of elastomer part 4.

[0074] FIG. 9 shows an adjusting mechanism 12b in the form of an adjustment by means of a spindle 60. Spindle 60 comprises an external thread 62. Spindle 60 is arranged and mounted rotatably on flange 23 which is arranged stationary on stator casing 5. In particular, spindle 60 is mounted stationary on flange 23, i.e. a rotation of spindle 60 brings about no change in the position of spindle 60 relative to flange 23. Spindle 60 comprises an adjustment shoulder 66. The latter can be constituted for example as a coupling for a motor or can serve as an attachment point for a manual adjustment of spindle 60.

[0075] According to an embodiment of the invention, a plurality of spindles (not represented) can be arranged around the outer circumference of stator 3. A first and driven spindle 60 can be coupled mechanically via a gearwheel 64 and a toothed ring 65 or other suitable coupling means to the other, non-driven spindles (not represented) in such a way that all the spindles can be adjusted together.

[0076] A second position-variable adjustment element 14 is arranged at the free end of elastomer part 4 of stator 3 (see FIG. 1). A supporting/compensating element 35 is provided between second position-variable adjustment element 14 and flange 23 serving as first stationary adjustment element 13, such as has been described for example in connection with FIGS. 3 to 6.

[0077] Second position-variable adjustment element 14 comprises a mounting for spindle 60 with an internal thread (not represented), in which spindle 60 is mounted rotatably, so that a rotation R of spindle 60 about its spindle longitudinal axis X60 brings about a movement of second position-variable adjustment element 14 in a movement direction B3.

[0078] FIG. 10 represents a part of adjusting mechanism 12c in the form of a toggle lever 70. A spindle 72 or toothed rod 73 with an external thread 74 is assigned to an adjustment element 75 in a rotatable manner. Two adjusting members 77 are arranged on spindle 72 by means of movably mounted connecting elements 76. One of adjusting members 77a is fixed stationary and forms first stationary adjustment element 13. The other adjusting member 77b is position-variable and forms second position-variable adjustment element 14. By actuating adjustment element 75, for example by rotation R, spindle 72 and is moved and in particular moved in movement direction B4. This movement is transmitted to adjusting member 77 via movable connecting elements 76, said adjusting members thus being moved closer together or farther apart, wherein position-variable adjusting member 77b is in particular moved relative to fixed adjusting member 77a.

[0079] FIG. 11 shows an adjusting mechanism 12d in the form of an adjustment by means of wedge rings 80, 82. Adjusting mechanism 12d comprises for example two external wedge rings 80a, 80b and two internal wedge rings 82a, 82b and sits on free end 8 of elastomer part 4 of the stator. External wedge ring 80b is arranged on a stationary part 13, for example on flange 23 of the stator casing (not represented). Position-variable adjustment element 14 is assigned to external wedge ring 80a lying opposite. The two internal wedge rings 82a, 82b sit on widened free end 8 of elastomer part 4 of the stator and are fixed to the latter. By rotating wedge rings 80a, 80b, 82a, 82b, their distance from one another is adjusted and the relative distance between flange 23 of the stator casing and free end 8 of elastomer part 4 of the stator is thus also varied.

[0080] FIG. 12 represents an adjusting mechanism 12e by means of a hydraulic or pneumatic hollow cylinder 90. Here, second position-variable adjustment element 14 is again arranged on widened free end 8 of elastomer part 4 of stator 3. Flange 23 on the stator casing 5 represents stationary adjustment element 13 and, in its outer regions, is raised in the direction of free end 8 of elastomer part 4 by a fitted ring or suchlike. At least one hydraulic or pneumatic hollow cylinder is arranged on second position-variable adjustment element 14. By actuating the hollow cylinder, in particular by filling or removing a suitable fluid, second position-variable adjustment element 14 can be moved in the direction of first stationary adjustment element 13 or in the opposite direction. The change in distance between the two adjustment elements 13, 14 brings about the desired deformation of elastomer part 4 and therefore an adjustment or readjustment of elastomer part 4 of stator 3. Similar to FIGS. 2 to 4, a supporting/compensating element 35 is again provided between second position-variable adjustment element 14 and flange 23 serving as first stationary adjustment element 13.

[0081] FIG. 13 shows an adjusting mechanism 12f, which achieves the adjustment of the relative distance of adjustment elements 13, 14 from one another with the aid of threads. Stationary adjustment element 13 is in an operative connection with position-variable adjustment element 14 by means of a thread arrangement. Position-variable adjustment element 14 is constituted as an adjustment ring 93 and is placed with a thread onto the flange of elastomer part 4. Adjustment ring 93 also accommodates a collar 95, which is fixed by means of a clamping ring 97. A stationary fastening ring is arranged at a free end 8 of elastomer part 4. A driving toothed wheel 94 and a toothed wheel 96 with an internal thread are assigned to fastening ring 92. Toothed wheel 96 with an internal thread in turn engages with position-variable adjustment element 14 or adjustment ring 93. The rotation of the thread of toothed wheels 94, 96 against one another brings about a movement of position-variable adjustment element 14 or adjustment ring 93 along longitudinal axis x3 of the stator (not represented) or of elastomer part 4.

[0082] FIG. 14 shows an adjusting mechanism 12g, which is constituted as a medium-actuated adjustment system, in particular a hydraulic or pneumatic adjustment system, using a membrane 45. The principle of medium-actuated adjusting mechanism 12g involves a modification of the idea of the adjustment by means of a hydraulic cylinder 46 according to FIG. 12. Here, the pretensioning between stator 3 and the rotor (not represented) is adjusted as a function of the pressure of a medium on membrane 45.

[0083] Hydraulic cylinder 46 comprises a cylinder part 47 fixed stationary and a cylinder part 48 mounted movably, on which membrane 45 is arranged in such a way that it separates hydraulic fluid H from the medium pumped by means of the eccentric screw pump. Hydraulic cylinder 46 is arranged at free end 8 of elastomer part 4 of stator 3, in particular cylinder part 48 mounted movably is fastened to the elastomer flange and cylinder part 47 fixed stationary is arranged and fixed on a stator casing 5.

[0084] Instead of positioning hydraulic cylinder 46 externally by way of a unit and a logic circuit/control, the pressure of the medium of the eccentric screw pump is used. This simplifies the system and reduces costs decisively. The required separation between hydraulic fluid H and medium is implemented by membrane 45 in the example of embodiment represented. When the pump pressure is increased, the pressure is transmitted via membrane 45 to hydraulic fluid H, which leads to a displacement of hydraulic cylinder 46. In particular, a pressure transmission D brings about a displacement of cylinder part 48 mounted movably relative to cylinder part 47 fixed stationary. The resetting of hydraulic cylinder 46 with a reduction in pressure takes place by means of the elastic force of the elastomer of elastomer part 4 and/or by additional components. By means of this interaction, the elastomer of elastomer part 4 is compressed to an extent such that optimum pretensioning between the rotor (not represented) and stator 3 is adjusted as a function of the pump pressure.

[0085] In this example of embodiment too, end region 9 of elastomer part 4 projecting out of stator casing 5 is also surrounded at least in sections by an encompassing (supporting) element 30, which at least partially covers and supports elastomer part 4 of stator 3 in exposed end region 9, in which elastomer part 4 is not surrounded by stator casing 5. Furthermore, there is a compensating element 36, which can compensate for the change in length of elastomer part 4 of the stator-rotor system of the eccentric screw pump relative to a stationary flange 20 of the eccentric screw pump.

[0086] According to a further embodiment, not represented, provision is made to distribute a plurality of hydraulic cylinders 46 at the circumference of free end 8 of elastomer part 4 of stator 3 and to actuate the latter according to the described principle.

[0087] According to a further embodiment, not represented, provision is made to use the end face of elastomer part 4 as a piston, on which the medium pressure of the pumped medium acts directly.

[0088] The invention has been described by reference to a preferred embodiment. A person skilled in the art can however envisage that modifications or changes to the invention can be made without thereby departing from the scope of protection of the following claims.