Stator lining, stator and method for producing a stator lining

Abstract

The invention relates to a stator lining (3) for a stator (1) of an eccentric screw pump, comprising: a rotor-receiving space (8) which is formed continuously on the stator lining (3) and axially with respect to a longitudinal centre axis (L) of the stator lining (3) from a suction end region of the stator lining (3) to a pressure end region of the stator lining (3); and at least one pressure chamber recess (17) which is arranged radially outwardly at a distance from the rotor-receiving space (8) and is radially outwardly open and / or at least one pressure chamber (24, 25) which is arranged radially outwardly at a distance from the rotor-receiving space (8) and is formed completely within the stator lining (3); wherein the pressure chamber recess (17) and / or the pressure chamber (24, 25) is / are connected so as to communicate with the pressure end region of the stator lining (3). In order to create a stator (1) by means of which backflow of a conveying medium to the suction side of the eccentric screw pump can be minimised as much as possible even at relatively high conveying pressure loads, the stator lining (3) is made of a material selected from a group including at least one metal, at least one metal alloy and at least one plastics material or plastics composite material having a hardness value of at least 65 on the Shore D hardness scale.

Description

[0001] Stator lining, stator and method for producing a stator lining

[0002] Technical area

[0003] The invention relates to a stator lining for a stator of an eccentric screw pump, comprising a rotor receiving space formed axially continuously on the stator lining with respect to a longitudinal center axis of the stator lining from a suction end region of the stator lining to a pressure end region of the stator lining and at least one pressure chamber recess arranged radially outwardly at a distance from the rotor receiving space and formed radially outwardly open and / or at least one pressure chamber arranged radially outwardly at a distance from the rotor receiving space and formed completely within the stator lining, wherein the pressure chamber recess and / or the pressure chamber are or are communicatively connected to the pressure end region of the stator lining.

[0004] The invention also relates to a stator for an eccentric screw pump, comprising at least one stator housing and at least one stator lining which is enclosed radially on the outside circumferentially by the stator housing with respect to a longitudinal center axis of the stator.

[0005] Furthermore, the invention relates to a method for producing a stator lining for a stator of an eccentric screw pump, wherein the stator lining is produced with a rotor receiving space formed axially continuously on the stator lining with respect to a longitudinal center axis of the stator lining from a suction end region of the stator lining to a pressure end region of the stator lining and at least one pressure chamber recess arranged radially outwardly at a distance from the rotor receiving space and formed radially outwardly open and / or at least one pressure chamber arranged radially outwardly at a distance from the rotor receiving space and formed completely within the stator lining, so that the pressure chamber recess and / or the pressure chamber are or are communicatively connected to the pressure end region of the stator lining.

[0006] State of the art: Progressing cavity pumps are traditionally used primarily for pumping viscous, highly viscous, and abrasive media. For this purpose, a progressing cavity pump comprises a stator and a rotor rotatably mounted within the stator, which is usually driven at its suction end to operate the progressing cavity pump.

[0007] DE 20 2021 106 537 U1 discloses an eccentric screw pump with a rotor forming a conveyor screw and a stator forming a screw flight, in which the rotor rotates during conveying operation. The stator has a stator housing in which a stator lining is located, which forms the screw flight. The stator lining is a sleeve that is supported on the stator housing at its outer circumference via a support structure that forms cavities. The support structure is designed and dimensioned depending on the location of its connection to the sleeve such that the support effect it provides is adapted to the local requirements of the sleeve.

[0008] In order to minimize the backflow of a pumped medium from the pressure side to the suction side of the progressing cavity pump, the stator lining can be manufactured with a certain undersize in relation to the rotor, so that the rotor elastically deforms the stator lining in a contact area with the stator lining. However, operational movements of the rotor relative to the stator lining inevitably lead to abrasion or wear of the stator lining. This reduces the contact force between the rotor and the stator lining, which can interrupt a helical contact line between the rotor and the stator lining. This is accompanied by increased backflow of the pumped medium and thus a reduced effectiveness of the progressing cavity pump.To counteract this, the stator lining or the entire stator must be replaced at regular intervals with a new stator lining or a new stator, which results in downtime of the progressing cavity pump and in maintenance costs.

[0009] EP 3 825 552 A1 discloses an eccentric screw pump with a rotor and a stator. The stator has at least one elastomer section, on which a pressure chamber is arranged on a side facing away from the rotor. The pressure chamber is connected to a pressure end region of the eccentric screw pump such that the elastomer section is exposed to a pressure generated by the eccentric screw pump in order to influence a contact pressure between the stator and the rotor.

[0010] Disclosure of the invention

[0011] An object of the invention is to provide a stator for an eccentric screw pump with which a backflow of a pumping medium to the suction side of the eccentric screw pump can be minimized as far as possible even at relatively high discharge pressure loads.

[0012] This object is achieved by the independent patent claims. Advantageous embodiments are recited in the dependent patent claims, the following description, and the figures, wherein these embodiments, each taken individually or in combination of at least two of these embodiments, may represent an advantageous and / or further developing aspect of the invention. Advantageous embodiments of the stator lining and the stator may correspond to advantageous embodiments of the method, and vice versa, even if this is not explicitly referred to in detail below.

[0013] A stator lining according to the invention for a stator of an eccentric screw pump has: a rotor receiving space formed axially continuously on the stator lining with respect to a longitudinal center axis of the stator lining from a suction end region of the stator lining to a pressure end region of the stator lining; and at least one pressure chamber recess arranged radially outwardly at a distance from the rotor receiving space and formed radially outwardly open and / or at least one pressure chamber arranged radially outwardly at a distance from the rotor receiving space and formed completely within the stator lining; wherein the pressure chamber recess and / or the pressure chamber are connected in a communicating manner to the pressure end region of the stator lining.and wherein the stator lining is formed from a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material having a hardness value of at least 65 on the Shore D hardness scale.

[0014] The terms “axial” and “radial” throughout this application refer to the longitudinal center axis of the stator lining or the stator.

[0015] During pumping operation of an eccentric screw pump equipped with a stator lining according to the invention, a pressurized pumping medium leaves the eccentric screw pump and is applied to the pressure end region of the stator lining. Since the pressure chamber recess or the pressure chamber is connected in a communicating manner to the pressure end region of the stator lining, the pressurized pumping medium enters the pressure chamber recess or the pressure chamber and completely fills it. This reliably prevents the rotor receiving space from expanding radially outward under higher pressure loads, which could interrupt a helical contact line between the rotor and the stator lining.This would inevitably result in a significantly increased backflow of the pumped medium to the suction end of the stator lining, which must be avoided at all costs to increase the efficiency of a suitably equipped eccentric screw pump. Instead, the invention permanently ensures that a suitably equipped eccentric screw pump maintains a high level of tightness, even at very high pressures, for example, in a range of 20 to 40 bar per stage of a suitably equipped eccentric screw pump, by ensuring that the stator lining maintains contact with the rotor with a nearly consistent quality.

[0016] At least one pressure chamber recess can be formed on the stator lining, which is arranged radially outwardly at a distance from the rotor receiving space and is open on the radial outside and is communicatively connected to the pressure end region of the stator lining. The pressure chamber recess can be open on an outer circumferential surface of the stator lining, i.e. can be formed at least partially as a depression on the outer circumferential surface of the stator lining, and can extend radially inward to a distance from the rotor receiving space. The pressure chamber recess is closed with respect to a suction end region, in particular with respect to an axial suction end face, of the stator lining. The pressure chamber recess can be communicatively connected to the pressure end region of the stator lining itself or via at least one channel formed on the stator lining.The pressure chamber recess can be connected in a communicating manner to a section of an inner circumferential surface of the stator lining arranged in the suction end region and surrounding the rotor receiving space radially on the outside and / or to a section of the axial pressure end face of the stator lining.

[0017] When the stator lining is inserted into a stator housing, the pressure chamber recess is completely closed radially on the outside by a stator housing section, so that a closed pressure chamber is formed between the stator lining and the stator housing, which is connected in communication with the pressure end region of the stator lining and in which a pressure build-up as described above can take place by introducing the conveying medium into the pressure chamber.

[0018] The pressure chamber recess can be formed completely circumferentially on the stator lining, so that the pressure described above can act radially inward on the stator lining from all sides. Alternatively, two or more corresponding pressure chamber recesses can be formed circumferentially offset from one another on the stator lining, each extending over only a portion of the circumference of the stator lining. These pressure chamber recesses can be arranged axially offset from one another or not.

[0019] Alternatively or additionally, at least one pressure chamber may be provided within the stator lining, arranged radially outwardly at a distance from the rotor receiving space, formed entirely within the stator lining, and communicating with the pressure end region of the stator lining. In contrast to the pressure chamber recess described above, the pressure chamber is not open on the radial outside, but rather closed.

[0020] The pressure chamber is not open, particularly at the suction end region, in particular at an axial suction end face, of the stator lining. The pressure chamber can be connected to the pressure end region of the stator lining either directly or via at least one channel formed on the stator lining. The pressure chamber can be connected to a section of an inner surface of the stator lining arranged in the suction end region, radially enclosing the rotor receiving space, and / or to a section of the axial pressure end face of the stator lining.

[0021] To allow the pressure described above to act radially inward from all sides on the stator lining or a section of the stator lining arranged between the pressure chamber and the rotor receiving space, at least a portion of the pressure chamber can be formed completely circumferentially on the stator lining. Alternatively, two or more corresponding pressure chambers can be formed circumferentially offset from one another on the stator lining, each extending over only a portion of the circumference of the stator lining. These pressure chambers may or may not be axially offset from one another.

[0022] The rotor receiving space, which runs axially continuously through the stator lining, serves to receive a rotor of the eccentric screw pump and for this purpose has at least one screw flight or a screw contour, which can be adapted to the respective intended use of a correspondingly equipped eccentric screw pump and can otherwise be of conventional design, for example.

[0023] According to the invention, the stator lining is formed from a material selected from a group comprising at least one metal, at least one metal alloy, and at least one plastic or plastic composite material with a hardness value of at least 65 on the Shore D hardness scale. As a result, the stator lining is harder than an elastomeric stator lining and is therefore essentially not elastically deformable. An elastomeric stator lining has the particular disadvantage that such a stator lining can collapse due to the differential pressure applied to it, which prevents the operation of a correspondingly equipped eccentric screw pump. Therefore, an elastomeric stator lining can only be used at relatively low pressures, whereas the elastomeric stator lining fails at higher pressures.With solid materials according to the invention, however, a higher pressure application is possible due to the higher strength, whereby a suitably equipped eccentric screw pump can be operated with higher pressures per stage of the eccentric screw pump, which is essential for many applications. A thermosetting or thermoplastic plastic, for example, can be used as the plastic. A fiber-reinforced or powder-reinforced plastic, for example, can be used as the plastic composite material. A fiber-reinforced plastic can have, for example, glass fibers, carbon fibers, ceramic fibers, aramid fibers, boron fibers, basalt fibers, steel fibers, natural fibers or nylon fibers as reinforcing fibers. The powder-reinforced plastic can be, for example, a polyvinylidene fluoride, a tetrafluoroethylene-hexafluoropropylene copolymer, a perfluoroalkoxy polymer or the like.The powder-reinforced plastic can be provided with a carbon or graphite powder.

[0024] In the case of a plastic or plastic composite material, this preferably has a hardness value of at least 65, preferably of at least 80, particularly preferably of at least 90, on the Shore D hardness scale.

[0025] For example, aluminum or copper can be used as the metal for the stator lining. Metal alloys for the stator lining can be steel, an aluminum alloy, or a copper alloy.

[0026] The stator lining according to the invention can be manufactured, for example, by injection molding, additive manufacturing, or mechanical material removal. The production of the stator lining can alternatively or additionally include a sintering process.

[0027] According to an advantageous embodiment, the pressure chamber recess is formed at least partially in a helical configuration around the stator lining. As a result, the pressure chamber recess is formed circumferentially around the stator lining and extends over part of the axial length of the stator lining. A winding direction (right-handed or left-handed) of the pressure chamber recess around the longitudinal center axis of the stator lining can be formed taking into account a winding direction of the screw contour on the inner surface of the stator lining surrounding the rotor receiving space. In particular, these winding directions can be in the same direction.Two or more corresponding pressure chamber recesses can also be formed on the stator lining, which can run parallel to one another, wherein two pressure chamber recesses arranged adjacent to one another can be separated from one another by a helically extending partition wall.According to a further advantageous embodiment, the stator lining has at least one inner lining section arranged radially inward, which has the rotor receiving space, and at least one outer lining section arranged radially outward to the inner lining section, via which outer lining section the inner lining section can be supported radially outward on a stator housing of the stator, wherein a depth of the pressure chamber recess varies according to an outer circumferential surface of the inner lining section, wherein the outer circumferential surface of the inner lining section corresponds to an enlargement of a screw contour on an inner circumferential surface of the stator lining enclosing the rotor receiving space and wherein the inner lining section has a constant material thickness.Due to this design of the inner lining section, it exhibits essentially uniform stability properties along its axial length, which can only be varied by the geometry of the inner lining section, which is defined by the screw contour. The inner lining section can be monolithically connected to the outer lining section and, in particular, can be partially or entirely made of the same material as the outer lining section.

[0028] According to a further advantageous embodiment, the pressure chamber extends helically over part of an axial length of the stator lining. A helical axis of the helical line formed by the pressure chamber preferably coincides with the longitudinal center axis of the stator lining. Due to the helical design of the pressure chamber, it is arranged partially or completely circumferentially on the stator lining, in particular on its outer lining section. Since the stator lining is closed at its axial suction end face, the pressure chamber ends at an axial distance from the axial suction end face. The pressure chamber can, for example, be designed as a helical bore with a circular cross-sectional area. Alternatively, the pressure chamber can have an elliptical, oval, or polygonal cross-sectional area.A winding direction of the pressure chamber around the longitudinal center axis of the stator lining can be formed, taking into account the winding direction of the screw contour on the inner surface of the stator lining surrounding the rotor receiving space. In particular, these winding directions can be in the same direction. Two or more corresponding pressure chambers can also be formed on the stator lining, which together can form a double or multiple helix.

[0029] According to a further advantageous embodiment, the stator lining has at least two pressure chambers arranged radially outwardly at a distance from the rotor receiving space and formed entirely within the stator lining, wherein a radially outwardly arranged pressure chamber has a larger cross-sectional area than a radially inwardly arranged pressure chamber. The radially inward inner pressure chamber can also be helical, so that this inner pressure chamber can also be formed partially or completely circumferentially on the stator lining. Since the stator lining is closed at its axial suction end face, the inner pressure chamber ends at an axial distance from the axial suction end face. The inner pressure chamber can, for example, be designed as a helical bore with a circular cross-sectional area. Alternatively, the pressure chamber can have an elliptical, oval, or polygonal cross-sectional area.A winding direction of the inner pressure chamber around the longitudinal center axis of the stator lining can be formed, taking into account the winding direction of the screw contour on the inner surface of the stator lining surrounding the rotor receiving space. In particular, these winding directions can be in the same direction. Two or more corresponding inner pressure chambers can also be formed on the outer lining section, which together form a double or multiple helix.

[0030] According to a further advantageous embodiment, the pressure chamber recess and / or the pressure chamber are / is communicatively connected to an axial pressure face of the stator lining. According to this embodiment, the pressure chamber recess or the pressure chamber is not communicatively connected to the inner surface of the stator lining, which has the screw contour, but exclusively to the axial pressure face of the stator lining. As a result, the pressure chamber recess or the pressure chamber is continuously accessible, regardless of the position of a rotor arranged in the rotor receiving space, in order to ensure the most uniform and uninterrupted pressurization of the pressure chamber recess or the pressure chamber.According to a further advantageous embodiment, the stator lining has at least one anti-rotation recess arranged on an outer surface of the stator lining and extending over part of the axial length of the stator lining, or at least one anti-rotation projection arranged on the outer surface of the stator lining and extending over part of the axial length of the stator lining. This can prevent the stator lining from rotating about its longitudinal center axis relative to a stator housing during operation of a correspondingly equipped eccentric screw pump. For this purpose, at least one anti-rotation projection that can be inserted into the anti-rotation recess of the stator lining, or at least one anti-rotation recess that receives the anti-rotation projection of the stator lining, can be arranged on an inner surface of the stator housing.This configuration is particularly advantageous when the stator lining is circularly cylindrical. This configuration can be omitted if the outer surface of the stator lining has a polygonal cross-section, for example, a square, hexagonal, or octagonal, which is possible in an alternative advantageous embodiment of the invention.

[0031] A stator according to the invention for an eccentric screw pump has at least one stator housing and at least one stator lining which is enclosed radially on the outside circumferentially by the stator housing with respect to a longitudinal center axis of the stator, wherein the stator lining is designed according to one of the above-mentioned embodiments or a combination of at least two of these embodiments.

[0032] The advantages mentioned above with regard to the stator lining are correspondingly associated with the stator. The stator housing is hollow-cylindrical and can have a circular or polygonal cross-sectional area. The stator housing can be made partially or entirely from a metal or a metal alloy. On a suction side of the stator housing, there can be at least one mechanical interface, for example a connecting flange, for connecting the stator to a conveying medium supply unit of the eccentric screw pump, via which the conveying medium can be supplied to the stator. The stator lining is enclosed radially on the outside by the stator housing in such a way that the outer circumferential surface of the stator lining is in contact with an inner circumferential surface of the stator housing.

[0033] According to an advantageous embodiment, the stator housing has a radially inward and circumferentially formed retaining shoulder on its axial pressure end face, against which the axial pressure end face of the stator lining axially rests. This prevents the stator lining from moving axially out of the stator housing during operation of a suitably equipped eccentric screw pump. The retaining shoulder is annular. The retaining shoulder extends radially inward to such an extent that the axial pressure end face of the stator lining is largely not covered by the retaining shoulder, in particular when the pressure chamber recess or the pressure chamber is connected in a communicating manner to the axial pressure end face of the stator lining, so that an opening on the axial pressure end face of the stator lining, via which the pressure chamber recess orPressure chamber is communicating with the axial pressure face of the stator lining and is covered by the retaining shoulder.

[0034] According to a further advantageous embodiment, the stator has at least one retaining ring that can be inserted into a circumferentially formed retaining groove on an inner surface of the intake end region of the stator housing, so that an axial intake end face of the stator lining rests axially against the retaining ring. This axially secures the stator lining on the intake side in the stator housing. By removing the retaining ring, the stator lining can be serviced or replaced with a new one if necessary.

[0035] According to a further advantageous embodiment, at least one anti-rotation projection engaging the anti-rotation recess of the stator lining and / or at least one anti-rotation recess into which the anti-rotation projection of the stator lining engages are arranged on an inner circumferential surface of the stator housing. This provides the corresponding advantages mentioned above with reference to the corresponding design of the stator lining. The anti-rotation projection on the stator housing can, for example, be designed as a longitudinally extending strip.According to a method according to the invention for producing a stator lining for a stator of an eccentric screw pump, the stator lining is produced with a rotor receiving space which is formed axially continuously on the stator lining from a suction end region of the stator lining to a pressure end region of the stator lining with respect to a longitudinal center axis of the stator lining, and with at least one pressure chamber recess which is arranged radially outwardly at a distance from the rotor receiving space and is open radially outward, and / or with at least one pressure chamber which is arranged radially outwardly at a distance from the rotor receiving space and is formed completely within the stator lining, so that the pressure chamber recess and / or the pressure chamber are connected in a communicating manner to the pressure end region of the stator lining.wherein the stator lining is made of a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material having a hardness value of at least 65 on the Shore D hardness scale.

[0036] The method provides the advantages mentioned above with regard to the stator lining or the stator. In particular, the method can be used to produce a stator lining according to one of the above-mentioned embodiments or a combination of at least two of these embodiments.

[0037] In the following, the invention is explained by way of example with reference to the attached figures using preferred embodiments, wherein the features explained below can represent an advantageous and / or further developing aspect of the invention both individually and in different combinations with one another.

[0038] Short description of the characters

[0039] It shows:

[0040] Fig. 1 is a schematic and perspective view of an embodiment of a stator according to the invention; Fig. 2 is a further schematic and perspective view of the stator shown in Fig. 1;

[0041] Fig. 3 is a schematic end view of the stator shown in Figs. 1 and 2;

[0042] Fig. 4 is a schematic longitudinal sectional view of the stator shown in Figs. 1 to 3 according to the section plane IV-IV of Fig. 3;

[0043] Fig. 5 is a schematic and perspective view of the stator lining of the stator shown in Figs. 1 to 4;

[0044] Fig. 6 is a schematic end view of the stator lining shown in Figs. 1 to 5;

[0045] Fig. 7 is a schematic side view of an inner lining portion of the stator lining shown in Figs. 1 to 6;

[0046] Fig. 8 is a schematic and perspective view of another embodiment of a stator lining according to the invention;

[0047] Fig. 9 is a further schematic and perspective view of the stator lining shown in Fig. 8;

[0048] Fig. 10 is a schematic end view of the stator lining shown in Figs. 8 and 9;

[0049] Fig. 11 is a further schematic end view of the stator lining shown in Figs. 8 and 9; and

[0050] Fig. 12 is a schematic longitudinal sectional view of the stator lining shown in Figs. 8 to 11 according to the section plane Xll-Xll of Fig. 10.

[0051] Detailed description of the characters

[0052] In the figures, identical or functionally identical components are provided with the same reference numerals. A repeated description of such components may be omitted below to avoid unnecessary repetition. Fig. 1 shows a schematic and perspective illustration of an exemplary embodiment of a stator 1 according to the invention for an eccentric screw pump (not shown). Among other things, an axial suction end face of the stator 1 is shown.

[0053] The stator 1 has a hollow-cylindrical stator housing 2 with an annular cross-sectional area. Furthermore, the stator 1 has a stator lining 3, which is enclosed radially outwardly by the stator housing 2 with respect to a longitudinal center axis L of the stator 1 and which is essentially circular-cylindrical in shape.

[0054] In addition, the stator 1 has a retaining ring 4 which is inserted into a circumferentially formed retaining groove 5 on an inner circumferential surface 6 of a suction end region of the stator housing 2, so that an axial suction end face 7 of the stator lining 3 rests axially on the retaining ring 4.

[0055] The stator lining 3 has a rotor receiving space 8 formed axially continuously on the stator lining 3 with respect to a longitudinal center axis L of the stator lining 3 from a suction end region of the stator lining 3 facing the viewer in Fig. 1 to a pressure end region of the stator lining 3 facing away from the viewer in Fig. 1.

[0056] The stator lining 3 has a radially inwardly arranged inner lining section 9, which has the rotor receiving space 8, and an outer lining section 10 arranged radially outwardly of the inner lining section 9, via which outer lining section 10 the inner lining section 9 is supported radially outwardly on the stator housing 2. This is shown in particular in Fig. 4. The outer circumferential surface of the inner lining section 9, shown in particular in Fig. 7, corresponds to an enlargement of a screw contour 11 on an inner circumferential surface 12 of the stator lining 3 enclosing the rotor receiving space 8. The inner lining section 9 has a constant material thickness, as shown in particular in Fig. 4.

[0057] The stator lining 3 is formed from a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material with a hardness value of at least 65 on the Shore D hardness scale. The stator lining 3 has an anti-rotation recess arranged on the outer circumferential surface of the stator lining 3 shown in Figs. 3 to 6 and extending over part of the axial length of the stator lining 3. On an inner circumferential surface of the stator housing 2 shown in Fig. 4, there is arranged an anti-rotation projection which engages in the anti-rotation recess of the stator lining 3. The anti-rotation projection is arranged via seven parallel to the longitudinal central axis L of the stator 1 orthe stator lining 3 is fixed to the stator housing 2 by screws 13 arranged in a row, which are passed through countersunk holes 14 of the stator housing 2 and screwed into the anti-rotation projection, as shown in Fig. 4.

[0058] Further embodiments of the stator 1 are described below with reference to Figs. 2 to 7.

[0059] Fig. 2 shows a further schematic and perspective view of the stator 1 shown in Fig. 1. Among other things, the axial pressure face of the stator 1 is shown.

[0060] The stator housing 2 has, at its pressure end region facing the viewer in Fig. 2, a radially inwardly and circumferentially formed retaining shoulder 15, against which the axial pressure end face 16 of the stator lining 3 facing the viewer in Fig. 2 axially rests.

[0061] The stator 1 has a plurality of pressure chamber recesses 17 which are arranged radially outwardly at a distance from the rotor receiving space 8 and are open on the radial outside and which are each connected in a communicating manner to the pressure end region of the stator lining 3 facing the viewer in Fig. 2. In particular, the pressure chamber recesses 17 are each connected in a communicating manner to the axial pressure end face 16 of the stator lining 3. The respective pressure chamber recess 17 is formed helically around the stator lining 3, as is shown in particular in Fig. 5. A depth of the respective pressure chamber recess 17 in the radial direction varies according to an outer surface of the inner lining section 9, shown in particular in Figs. 4 and 7, which is shown in particular in Figs. 2 to 4 and 6. The pressure chamber recesses 17 are arranged circumferentially offset from one another. Fig. 3 shows a schematic end view of the pressure chamber recess 17 shown in Figs.1 and 2, wherein the axial pressure face of the stator 1 is shown.

[0062] The anti-rotation recess 19 of the stator lining 3 is shown, arranged on the outer circumferential surface 18 of the stator lining 3 and extending over part of the axial length of the stator lining 3. Also shown is the anti-rotation projection 20 of the stator 1, arranged on the inner circumferential surface of the stator housing 2, shown in particular in Fig. 4, and engaging in the anti-rotation recess 19.

[0063] Fig. 4 shows a schematic sectional view of the stator 1 shown in Figs. 1 to 3 according to the sectional plane IV-IV of Fig. 3.

[0064] In particular, it is shown how the strip-shaped anti-rotation projection 20 is fixed to the inner circumferential surface 6 of the stator housing 2 by means of the screws 13. Furthermore, it is shown that the outer circumferential surface 21 of the inner lining section 9 corresponds to an enlargement of the worm contour 11 on the inner circumferential surface 12 of the stator lining 3 enclosing the rotor receiving space 8, wherein the inner lining section 9 has a constant material thickness for this purpose. Furthermore, it is shown that the depth of the respective pressure chamber recess 17 varies according to the outer circumferential surface 21 of the inner lining section 9. Pressure chamber recesses 17 arranged adjacent to one another are separated from one another by a helically extending partition wall 22, which forms part of the outer lining section 10 of the stator lining 3.

[0065] Fig. 5 shows a schematic and perspective view of the stator lining 3 of the stator shown in Figs. 1 to 4. In particular, the helically extending pressure chamber recesses 17 and partition walls 22 are shown, wherein the pressure chamber recesses 17 end at a distance from the axial suction end face 7 of the stator lining 3. The axial suction end face 7 is formed by a disk-shaped axial end section 23 of the stator lining 3. The anti-rotation recess 19 also ends at the axial end section 23 and is axially open at its other end on the axial pressure end face of the stator lining 3 facing away from the viewer in Fig. 5. The anti-rotation recess 19 is thus designed as a longitudinal groove.

[0066] Fig. 6 shows a schematic end view of the stator lining 3 shown in Figs. 1 to 5. The axial pressure end face 16 of the stator lining 3 is shown, at which the anti-rotation recess 19 and the pressure chamber recesses 17 end or open.

[0067] Fig. 7 shows a schematic side view of the inner lining section 9 of the stator lining 3 shown in Figs. 1 to 6. The outer lining section shown in Figs. 1 to 6 has been omitted in order to better illustrate the design of the inner lining section 9. It is also shown that the outer circumferential surface 21 of the inner lining section 9 is an enlargement of the screw contour shown in Figs. 1 to 6.

[0068] Fig. 8 shows a schematic and perspective view of another embodiment of a stator lining 3 according to the invention for a stator (not shown) of a progressing cavity pump (not shown). The stator lining 3 can be combined with the stator housing shown in Figs. 1 to 4 to form a stator. Among other things, an axial pressure face 16 of the stator lining 3 is shown, which faces the viewer of Fig. 8.

[0069] The stator lining 3 has a rotor receiving space 8 which is formed axially continuously on the stator lining 3 with respect to a longitudinal central axis L of the stator lining 3 from a suction end region of the stator lining 3 facing away from the viewer of Fig. 8 to a pressure end region of the stator lining 3 facing the viewer of Fig. 8.

[0070] The stator lining 3 has a radially inwardly arranged inner lining section 9, which has the rotor receiving space 8, and an outer lining section 10 arranged radially outwardly of the inner lining section 9, via which outer lining section 10 the inner lining section 9 can be supported radially outwardly on a stator housing (not shown). The outer circumferential surface of the inner lining section 9, shown in particular in Fig. 7, corresponds to an enlargement of a screw contour 11 on an inner circumferential surface 12 of the stator lining 3 surrounding the rotor receiving space 8. The inner lining section 9 has a constant material thickness.

[0071] The stator lining 3 is formed from a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material having a hardness value of at least 65 on the Shore D hardness scale.

[0072] On an outer surface 18 of the stator lining 3, an anti-rotation recess 19 is arranged, extending over part of the axial length of the stator lining 3 and axially open at the axial pressure end face 16 of the stator lining 3. The anti-rotation recess 19 is designed as a longitudinal groove that ends at a distance from the axial suction end face of the stator lining 3.

[0073] The stator lining has fifteen pressure chambers 24 arranged radially outwardly at a distance from the rotor receiving space 8 and formed entirely within the stator lining 3, each of which is communicatively connected to the pressure end region of the stator lining 3. In particular, the respective pressure chamber 24 is communicatively connected to the axial pressure end face 16 of the stator lining 3.

[0074] Each of the pressure chambers 24 extends helically over a portion of the axial length of the stator lining 3. The pressure chambers 24 have a common helical axis that is identical to the longitudinal center axis L of the stator lining 3, so that the pressure chambers 24 form a multiple helix. The pressure chambers 24 are arranged at equal circumferential offsets from one another. Each pressure chamber 24 has a circular cross-sectional area.

[0075] In addition, the stator lining has six pressure chambers 25 arranged radially outwardly from the rotor receiving space 8, formed entirely within the stator lining 3 and arranged radially inward from the pressure chambers 24. The radially outer pressure chambers 24 each have a larger cross-sectional area than a radially inner pressure chamber 25. Three radially inner pressure chambers 25 are arranged in a row next to one another on opposite sides of the rotor receiving space 8, specifically in a region in which the stator lining 3 has a greater wall thickness. The radially inner pressure chambers 25 are also each communicating with the pressure end region of the stator lining 3. In particular, the respective radially inner pressure chamber 25 is communicating with the axial pressure end face 16 of the stator lining 3.

[0076] Each of the radially inner pressure chambers 25 extends helically over a portion of an axial length of the stator lining 3. The radially inner pressure chambers 25 have a common helical axis that is identical to the longitudinal center axis L of the stator lining 3, so that the radially inner pressure chambers 25 also form a multiple helix. Each radially inner pressure chamber 25 has a circular cross-sectional area.

[0077] Further embodiments of the stator 1 are described below with reference to Figs. 9 to 12.

[0078] Fig. 9 shows a further schematic and perspective view of the stator lining 3 shown in Fig. 8. Among other things, an axial suction end face 10 of the stator lining 3 is shown, which faces the viewer of Fig. 9.

[0079] Fig. 10 shows a schematic end view of the stator lining 3 shown in Figs. 8 and 9. Among other things, the axial pressure end face 16 of the stator lining 3 is shown, at which the pressure chambers 24 and 25 open.

[0080] Fig. 11 shows a further schematic end view of the stator lining 3 shown in Figs. 8 and 9. Among other things, the axial suction end face 10 of the stator lining 3 is shown.

[0081] Fig. 12 shows a schematic longitudinal sectional view of the stator lining 3 shown in Figs. 8 to 11 according to the sectional plane XII-XII from Fig. 10. Using the example of a radially inner pressure chamber 25a, it is shown how the radially inner pressure chambers 25 wind through the stator lining 3. Furthermore, using the example of a radially outer pressure chamber 24a, it is shown how the radially outer pressure chambers 24 wind through the stator lining 3. The radially outer pressure chambers 24 or the walls radially outwardly closing them protrude slightly into the anti-rotation recess 19, whereby a rib structure is formed in the anti-rotation recess 19, which is also shown in Figs. 8 and 9. In an alternative embodiment, the radially outer pressure chambers 24 do not protrude correspondingly into the anti-rotation recess 19, so that the latter has a smooth bottom.

[0082] List of reference symbols

[0083] 1 stator

[0084] 2 stator housings

[0085] 3 Stator lining

[0086] 4 Retaining ring

[0087] 5 locking groove

[0088] 6 inner surface of 2

[0089] 7 axial suction end face of 3

[0090] 8 Rotor receiving space

[0091] 9 inner lining section

[0092] 10 outer lining section

[0093] 11 Screw contour

[0094] 12 inner surface of 9

[0095] 13 Screw

[0096] 14 Countersunk hole on 2

[0097] 15 Holding shoulder

[0098] 16 axial pressure face of 3

[0099] 17 Pressure chamber recess

[0100] 18 Outer surface area of ​​3.10

[0101] 19 Anti-rotation recess on 18

[0102] 20 Anti-rotation projection

[0103] 21 outer surface of 9

[0104] 22 Partition wall

[0105] 23 axial end section of 3

[0106] 24 radial outer pressure chamber

[0107] 25 radial inner pressure chamber L longitudinal center axis of 1 , 2, 3

Claims

Patent claims 1. Stator lining (3) for a stator (1) of an eccentric screw pump, comprising: a rotor receiving space (8) formed axially continuously on the stator lining (3) with respect to a longitudinal center axis (L) of the stator lining (3) from a suction end region of the stator lining (3) to a pressure end region of the stator lining (3); and at least one pressure chamber recess (17) arranged radially outwardly at a distance from the rotor receiving space (8) and formed radially outwardly open, and / or at least one pressure chamber (24, 25) arranged radially outwardly at a distance from the rotor receiving space (8) and formed entirely within the stator lining (3); wherein the pressure chamber recess (17) and / or the pressure chamber (24, 25) are connected in a communicating manner to the pressure end region of the stator lining (3).is characterized in that the stator lining (3) is formed from a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material having a hardness value of at least 65 on the Shore D hardness scale.

2. Stator lining (3) according to claim 1, characterized in that the pressure chamber recess (17) is formed at least partially helically circumferentially on the stator lining (3).

3. Stator lining (3) according to claim 1 or 2, characterized by at least one radially inwardly arranged inner lining section (9), which has the rotor receiving space (8), and at least one radially outwardly arranged outer lining section (10) to the inner lining section (9), via which outer lining section (10) the inner lining section (9) can be supported radially outwardly on a stator housing (2) of the stator (1), wherein a depth of the pressure chamber recess (17) varies according to an outer circumferential surface (21) of the inner lining section (9), wherein the outer circumferential surface (21) of the inner lining section (9) corresponds to an enlargement of a screw contour (11) on a the inner circumferential surface (12) of the stator lining (3) surrounding the rotor receiving space (8) and wherein the inner lining section (9) has a constant material thickness.

4. Stator lining (3) according to claim 1, characterized in that the pressure chamber (24, 25) extends helically over a part of an axial length of the stator lining (3).

5. Stator lining (3) according to claim 1 or 4, characterized by at least two pressure chambers (24, 25) arranged radially outwardly at a distance from the rotor receiving space (8) and formed entirely within the stator lining (3), wherein a pressure chamber (24) arranged radially outwardly has a larger cross-sectional area than a pressure chamber (25) arranged radially inwardly.

6. Stator lining (3) according to one of claims 1 to 5, characterized in that the pressure chamber recess (17) and / or the pressure chamber (24, 25) are or are connected in a communicating manner to an axial pressure end face (16) of the stator lining (3).

7. Stator lining (3) according to one of claims 1 to 6, characterized by at least one anti-rotation recess (19) arranged on an outer circumferential surface (18) of the stator lining (3) and extending over part of the axial length of the stator lining (3) or at least one anti-rotation projection arranged on the outer circumferential surface (18) of the stator lining (3) and extending over part of the axial length of the stator lining (3).

8. Stator (1) for an eccentric screw pump, comprising at least one stator housing (2) and at least one stator lining (3) which is enclosed radially on the outside by the stator housing (2) with respect to a longitudinal center axis (L) of the stator (1), characterized in that the stator lining (3) is designed according to one of claims 1 to 7.

9. Stator (1) according to claim 8, characterized in that the stator housing (2) has a radially inwardly and circumferentially formed Retaining shoulder (15) against which the axial pressure face (16) of the stator lining (3) rests axially.

10. Stator (1) according to claim 8 or 9, characterized by at least one retaining ring (4) which can be inserted into a circumferentially formed retaining groove (5) on an inner circumferential surface (6) of the suction end region of the stator housing (2), so that an axial suction end face (10) of the stator lining (3) bears axially against the retaining ring (4).

11. Stator (1) according to one of claims 8 to 10, characterized in that on an inner circumferential surface (6) of the stator housing (2) at least one anti-rotation projection (20) engaging in the anti-rotation recess (19) of the stator lining (3) and / or at least one anti-rotation recess into which the anti-rotation projection of the stator lining (3) engages are or is arranged.

12. Method for producing a stator lining (3) for a stator (1) of an eccentric screw pump, wherein the stator lining (3) is produced with a rotor receiving space (8) formed axially continuously on the stator lining (3) with respect to a longitudinal center axis (L) of the stator lining (3) from a suction end region of the stator lining (3) to a pressure end region of the stator lining (3), and with at least one pressure chamber recess (17) arranged radially outwardly at a distance from the rotor receiving space (8) and formed radially outwardly open, and / or with at least one pressure chamber (24, 25) arranged radially outwardly at a distance from the rotor receiving space (8) and formed completely within the stator lining (3), so that the pressure chamber recess (17) and / or the pressure chamber (24, 25) are connected in a communicating manner to the pressure end region of the stator lining (3).is characterized in that the stator lining (3) is made of a material selected from a group comprising at least one metal, at least one metal alloy and at least one plastic or plastic composite material having a hardness value of at least 65 on the Shore D hardness scale.

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