DE102022100652A1 - Stator for an eccentric screw pump - Google Patents

Abstract

A stator (10) for an eccentric screw pump for conveying a flowable medium, in particular mortar, plaster or another flowable or pasty building material mixture, is provided for receiving a snail-shaped rotor and has a casing (12) made of at least one rigid material, in particular metal. and an inner part (14) made of at least one elastic material, in particular elastomer, and a stator axis (A). An inner surface (15) of the inner part (14) is designed with a thread, in particular with two or more threads. The jacket (12) forms a connection area (13) on a pressure-side and/or front end (18) for connection to a pressure line or a pressure flange (40). The outer surface or outer contour and/or the inner surface or inner contour of the jacket (12) in the connection area (13) forms at least approximately the inner surface (15) or inner contour of the inner part.

Description

The invention relates to a stator for an eccentric screw pump for conveying a flowable medium, in particular mortar, plaster or another flowable or pasty building material mixture. Furthermore, the invention relates to a corresponding eccentric screw pump.

Eccentric screw pumps (or: Moineau pumps) for conveying a flowable medium, for example mortar, plaster or the like, comprise a rotor and a stator, in which a worm-shaped or coiled rotor rotates in an eccentric rotary movement in an internal thread of the stator running around a stator axis and oscillates. For the state of the art, we refer, for example, to the stators and progressing cavity pumps from Knauf PFT (see e.g. https://www.pft.net/de/rotorstator/)

During the eccentric rotary movement of the rotor, the rotor rolls or rolls on the inner thread wall of the stator and elastically sealed chambers are formed between the inner thread of the stator and the rotor, which migrate from a suction side to a pressure side of the stator, so that the medium in them Chambers in the corresponding conveying direction from the suction side to the pressure side is funded or pumped. The conveyed volume is directly proportional to the speed of the rotor.

The rotor of known progressing cavity pumps consists of a rigid material, in particular a metal such as steel. The helical rotor has a circular (or elliptical) cross-section, viewed axially of its central axis, winding axially about the central axis along a helical or helix line having a large rotor pitch and pitch. As a result, the rotor has an external thread with this rotor thread pitch with a round thread profile corresponding to the circular (or elliptical) cross section. The rotor is driven to rotate about its axis of rotation by a rotary drive and is coupled to the rotary drive in an articulated or elastic manner. When the rotor is inserted, the central axis of the rotor coincides with the stator axis of the stator thread and forms the axis of rotation of the rotary drive for the rotor. The stator thread pitch of the internal thread in the stator is twice the rotor thread pitch. The internal thread of the stator is usually a two-start internal thread with a large thread depth.

The stator typically has a shell of a rigid material, particularly a metal such as steel, and an insert or core of a resilient material, particularly an elastomer, within the shell. The inner part rests with its outer surface on the inner surface of the shell and is firmly connected to it. The inside of the inner part has a (double-start) internal thread around the stator axis.

The cross-section of the thread on the inner surface in the stator is stadium-shaped, i.e. formed from two convex, semi-circular inner contour sections and two straight inner contour sections which are arranged in between and run parallel to one another. The distance between the two parallel straight inner contour sections and the diameter of the two semicircular inner contour sections are adapted to the diameter of the circular cross section of the rotor. During the eccentric rotation of the rotor around the axis of rotation, the circular rotor cross-section oscillates or moves back and forth at each axial position over time in the stadium-shaped cross-section of the internal thread in the stator, namely between the two convex internal contour sections along the straight internal contour sections, i.e. the longitudinal axis of the eccentric cross section. At the end points of this eccentric pendulum movement, the rotor rests with its circular rotor cross section on the respective semicircular inner contour section and thereby seals off the chamber(s) moving in the conveying direction at the resulting circular contact line. After a full eccentric revolution of the rotor around the axis of rotation, the rotor cross-section is again in the same angular position to the stator, so that in the distance of the thread pitch of the rotor, two consecutive contact lines each seal an intermediate chamber between the rotor external thread and the stator internal thread, which in the Internal thread of the stator moved to the pressure side.

The outside of the casing of the stator can now be smooth in a known design, in particular cylindrical or conical. In an alternative known embodiment, the casing follows the eccentric two-start thread shape of the inner part both on its inner surface and on its outer surface, as a result of which a substantially uniform wall thickness of the inner part in the axial direction is possible. A combination of the two outer shell shapes is also possible. In the known stators, the shell wall thickness is generally at least approximately constant or uniform.

At the pressure-side end of the stator, the stator casing in the known progressing cavity pumps transitions into a cylindrical connection area which is inserted or plugged into a cylindrical counter-connection in a form-fitting manner, which in turn is connected to a pressure flange Hose is connected, or can be provided directly on a hose. The flowable medium, in particular the plaster mortar, is conveyed to the processing site via the hose.

The connections of the stator and pressure flange or hose that are plugged into or inserted into one another are clamped or held against one another directly using fastening means such as clamps or the like or via a holding frame of the eccentric screw pump, the drive of the rotor also being held on the holding frame.

The object of the invention is to provide a new stator for an eccentric screw pump and a new eccentric screw pump.

This object is achieved in particular by a stator for an eccentric screw pump according to patent claim 1 or patent claim 2 and an eccentric screw pump with such a stator according to patent claim 9 .

Further configurations and developments according to the invention result in particular from the patent claims which are dependent on patent claims 1 and 9 in each case.

The claimable feature combinations and objects according to the invention are not limited to the selected wording and the selected dependencies of the patent claims. Each feature in the patent claims, also independently of their dependencies, can be claimed in any combination with one or more other feature(s) in the patent claims. In addition, each feature described or disclosed in the description or drawing may, on its own, independently or detached from the context in which it is found, alone or in any combination with one or more other features, which are set out in the claims or is or are described or disclosed in the specification or drawing.

In one embodiment according to patent claim 1, the stator is suitable for an eccentric screw pump for conveying a flowable medium, in particular mortar, plaster or another flowable or pasty building material mixture, and is intended for receiving a snail-shaped rotor and comprises a stator axis and a casing made of at least one rigid Material, in particular metal, and an inner part made of at least one elastic material, in particular elastomer. An inner surface of the inner part is designed in the form of a thread or with a thread, in particular with two or more threads. On a pressure-side and/or front end, the jacket has a connection area for connection to a pressure line or a pressure flange (or: the jacket forms this connection area).

According to the invention, in an embodiment according to an alternative f1) of patent claim 1, the outer surface or outer contour and/or the inner surface or inner contour of the jacket in the connection area is at least approximately designed to reproduce or adapted to the inner surface or inner contour of the inner part or follows it (in its course) at least approximately the, in particular double or multi-start, thread of the inner part.

• - entweder, insbesondere bei einem zweigängigen Gewinde an der Innenfläche, exzentrisch ausgebildet ist, d.h. in zwei zueinander orthogonalen Richtungen unterschiedlich große Außendurchmesser aufweist und vorzugsweise zwei gerundete und/oder konvexe Randbereiche aufweist,
• - oder eine, insbesondere bei einem dreigängigen Gewinde an der Innenfläche, dreieckige Grundform oder eine, insbesondere bei einem viergängigen Gewinde an der Innenfläche, viereckige Grundform jeweils mit gerundeten und/oder konvexen Eck- oder Randbereichen.

In an embodiment according to a further alternative f2) of claim 1, the casing has a cross section perpendicular to the stator axis in the connection area, which cross section

• - either, especially in the case of a two-start thread on the inner surface, is designed eccentrically, ie has external diameters of different sizes in two mutually orthogonal directions and preferably has two rounded and/or convex edge regions,
• - or a triangular basic shape, in particular with a three-start thread on the inner surface, or a square basic shape, in particular with a four-start thread on the inner surface, each with rounded and/or convex corner or edge regions.

In this embodiment, the cross-section of the jacket in the connection area corresponds generally at least approximately to the eccentric basic shape of a two-start thread or the triangular basic shape of a three-start thread or the quadrangular basic shape of a four-start thread on the inner surface of the inner part or depicts it, i.e. the outer surface of the jacket follows at least approximately this thread form of the inner surface of the inner part.

This design of the connection area on the stator enables a positive, stable and torsion-proof connection of the stator to the pressure flange or the pressure line. Furthermore, the outlet areas for the flowable medium on the pressure side are well-defined, which means that the internal geometry of the pressure flange or connection to the pressure line can be further optimized in terms of flow technology. An axial stop of the rotor can also be positioned in such a way that a narrowing of the flow cross section is minimized.

In a preferred embodiment, the outer surface or the outer contour and/or inner surface or the inner contour or the cross section of the casing of the stator is provided with an oval or elliptical or stadium-like (or: stadium-shaped) or bone-shaped (or: shape) shape in the connection area.

As a rule, the outer surface or the outer contour and/or the inner surface or the inner contour or the cross section of the casing of the stator is at least partially (seen from the inside) convexly curved in the connection area.

In an advantageous embodiment, the outer surface or the outer contour and/or inner surface or the inner contour or the cross section of the jacket in the connection area runs essentially at the same radial distance or parallel to the inner surface or inner contour or the cross section of the inner part.

However, the outer surface or the outer contour and/or the inner surface or inner contour or the cross section of the jacket in the connection area can also run at a (slightly) varying radial distance from the inner surface or inner contour or the cross section of the inner part, for example an oval, i.e. convex all around Have a stadium-like shape, i.e. convex at the edges, in particular circular, and straight in the middle, inner surface or inner contour or stadium-shaped cross-section of the inner part.

The inner surface of the inner part preferably has the thread over its entire axial length along the stator axis. In general, the casing and the inner part are designed as hollow bodies along the stator axis.

In one embodiment of the stator, the casing has a thread-shaped section on its outer surface or in its cross section, at least over an axial partial area, the course of which is adapted to the thread of the inner surface of the inner part or follows this thread, with the connection area preferably being a pressure-side and / or front end area of the threaded section of the jacket. Furthermore, the cross section of the outer wall of the connection area preferably corresponds to a cross section through the jacket in the threaded section and/or is produced by cutting to length or cutting transversely to the stator axis in the threaded section.

In an advantageous embodiment, the threaded section of the casing extends over the entire axial length of the casing along the stator axis.

In a likewise advantageous embodiment, the thread-shaped section of the jacket extends only, starting from the pressure side, over an axial partial area which is adjoined by a smooth section of the jacket towards the suction side. In the smooth section, the shell is preferably cylindrical or conical.

The maximum outer diameter of the shell is preferably substantially constant in the threaded section.

In the smooth section, the maximum outer diameter of the shell is either constant and corresponds to the maximum outer diameter of the shell in the threaded section, or transitions from a larger maximum outer diameter on the suction side to a smaller maximum outer diameter at the transition to the threaded section of the shell.

In general, an outside of the inner part rests at least predominantly on an inside of the jacket and is firmly connected to it.

In one embodiment, the average or the smallest inner diameter of the thread on the inner surface of the inner part is constant axially to the stator axis or, in another embodiment, it is larger on the suction side than on the pressure side.

1. a) Vorsehen oder Bereitstellen (wenigstens) eines langgestreckten Rohlings, der ein durchgehendes Rohlinginnenteil und einen durchgehenden, das Rohlingsinnenteil umgebenden Rohlingmantel aufweist, wobei die Innenfläche des Rohlinginnenteils und die Außenfläche des Rohlingmantels eine dem für die jeweiligen Innenteile und die jeweiligen Mäntel der Statoren vorgesehenen Gewinde entsprechendes, insbesondere zwei- oder mehrgängiges, Rohlingsgewinde aufweisen,
2. b) Ablängen des langgestreckten Rohlings an den gewünschten axialen Längen der Statoren und Verwenden der abgelängten Bereiche als oder für die Statoren mit ihren Anschlussbereichen.

Furthermore, a method for producing a plurality of stators according to the invention is proposed with the method steps:

1. a) Providing or providing (at least) an elongate blank which has a continuous blank inner part and a continuous blank casing surrounding the blank inner part, the inner surface of the blank inner part and the outer surface of the blank casing having a thread provided for the respective inner parts and the respective casings of the stators have a corresponding, in particular double or multi-start, blank thread,
2. b) Cutting the elongated blank to length at the desired axial lengths of the stators and using the cut-to-length areas as or for the stators with their connection areas.

The invention further relates to an eccentric screw pump for conveying a flowable medium, in particular a flowable building material mixture such as mortar or plaster, which has a stator according to an embodiment according to the invention (and arranged in the stator and eccentric has a rapidly rotating snail-shaped rotor and a pressure flange or pressure line connected to the connection area of the stator.

The pressure flange preferably includes a receiving area for the connection area of the stator. The receiving area, which is designed in particular as a recess, has an inner wall and a support surface which is at least partially surrounded by the inner wall. The inner wall of the receiving area has, at least in sections, a shape or form adapted to the outer surface of the connecting area of the stator, so that a positive connection or positive insertion of the connecting area of the stator into the receiving area of the pressure flange is made possible. An end face of the jacket in the connection area of the stator is supported or can be supported on the support surface of the receiving area.

In a further embodiment, the pressure flange comprises a receiving area for the connection area of the stator, the receiving area having an outer wall and a support surface at least partially surrounding the outer wall, and the outer wall of the receiving area at least in sections having a shape adapted to the inner surface of the connection area of the stator so that a form-fitting connection or a form-fitting insertion of the connection area of the stator into the receiving area of the pressure flange is made possible, with one end face of the casing being supported or able to be supported in the connection area of the stator on the support surface of the receiving area of the pressure flange.

In a further development, the pressure flange has a web in the receiving area, in particular running inside the inner wall or outside the outer wall, preferably lower, starting from the support surface, which abuts or presses in a sealing manner on the end face of the inner part of the stator in the connection area.

• 1 ein Stator mit einem darin befindlichen Rotor in einem Längsschnitt,
• 2 ein Stator mit einem von der Saugseite zur Druckseite hin abnehmenden minimalen Innendurchmesser in einem Längsschnitt,
• 3 ein Stator mit einem konstanten minimalen Innendurchmesser in einem Längsschnitt,
• 4 eine weitere Ausführungsform eines Stators in einer perspektivischen Ansicht,
• 5 der Stator gemäß 4 in einer Stirnansicht von der Druckseite her,
• 6 ein Druckflansch in einer perspektivischen Ansicht,
• 7 der Druckflansch gemäß 6 in einer Draufsicht,
• 8 ein Stator mit darin befindlichem Rotor und angeschlossenem Druckflansch in einem Längsschnitt und
• 9 ein vergrößerter Ausschnitt des Anschlussbereichs von Stator und Druckflansch gemäß 8 in einem Längsschnitt

jeweils schematisch dargestellt sind. Einander entsprechende Teile und Größen sind in den 1 bis 9 mit denselben Bezugszeichen versehen.The invention is explained in more detail below using exemplary embodiments. Reference is made to the drawings in which

• 1 a stator with a rotor inside in a longitudinal section,
• 2 a stator with a minimum inner diameter decreasing from the suction side to the pressure side in a longitudinal section,
• 3 a stator with a constant minimum inner diameter in a longitudinal section,
• 4 a further embodiment of a stator in a perspective view,
• 5 the stator according to 4 in an end view from the pressure side,
• 6 a pressure flange in a perspective view,
• 7 the pressure flange according to 6 in a top view,
• 8th a stator with a rotor inside and a connected pressure flange in a longitudinal section and
• 9 an enlarged section of the connection area of the stator and pressure flange according to 8th in a longitudinal section

are each shown schematically. Corresponding parts and sizes are in the 1 until 9 provided with the same reference numbers.

In the 1 until 9 are a stator with 10, a jacket with 12, a connection area with 13, an inner part (or insert) with 14, a suction side with 16, a pressure side with 18, a rotor with 30, a pressure flange with 40, a stator axis with A and a conveying direction is denoted by F. An end face of the inner part 14 on the pressure side 18 is denoted by 14A, an end face of the jacket 12 on the pressure side 18 by 12A and an end face of the connection area 13 on the pressure side 18 by 13A.

The progressing cavity pump is intended for conveying a flowable medium, for example mortar, plaster or another flowable or pasty building material mixture, and for this purpose comprises a stator 10 and a rotor 30.

The rotor 30 is designed helically with a predetermined, high thread pitch and can be designed in a manner known per se by having a circular rotor cross section, which extends along a helical or external thread line about a central axis of the rotor 30, which when the rotor 30 is assembled with the stator axis A coincides, runs. According to the Moineau principle, the worm-shaped rotor 30 moves in a rotational movement or rotation R around the stator axis A with an eccentric compensating movement within the eccentric-thread-shaped inner part 14 of the stator 10. The resulting cavities H between the outer surface 32 of the rotor 30 and of the inner surface 15 of the stator 10 move in the conveying direction F and thus convey the flowable medium or material to be conveyed, in particular the pasty (or: viscous) or fluid building material mixture such as a wet plaster mortar. A suction side 16 is provided upstream of the conveying direction F and downstream in the conveying direction F is a pressure side 18 on the front ends of the stator 10 or on the ends axial to the stator axis A.

In the exemplary embodiments, the stator 10 comprises the casing (or: an outer wall or casing wall) 12 made of a rigid material, for example steel or another metal, and the inner part 14 made of an elastic material, for example an elastomer or rubber material. The inner part 14 is surrounded and protected and stabilized by the jacket 12 and rests with its outside on an inside of the jacket 12 .

The inner part 14 of the stator 10 has, over its entire axial length along the stator axis A, the eccentrically threaded inner surface 15 that is typical of an eccentric screw pump. Such an eccentric-threaded inner surface 15 has a thread with an eccentric cross-section perpendicular to the stator axis A, in which the rotor 30 moves eccentrically rotating. The eccentricity for the eccentric movement of the rotor 30 is in particular in 5 to recognize. The thread pitch of this internal thread or this threaded inner surface in the stator 10 is an even multiple, preferably twice, the thread pitch of the rotor 30. The internal thread or the threaded inner surface 15 of the stator 10 is preferably formed with two threads, with each of the two threads having twice the thread pitch as the Rotor 30 has and preferably the eccentric cross-section of the inner surface 15 is formed equally in each of the two threads of the thread.

The jacket 12 of the stator 10 surrounding the inner part 14 has in the preferred embodiments shown, starting axially at the suction side 16, a smooth section 20 and then, axially in the conveying direction F and ending at the pressure side 18, an eccentric thread-shaped (or : having or forming a thread with eccentricity) Section 22.

However, in exemplary embodiments that are not shown, it is also possible to omit the smooth section 20 and to design the jacket 12 over its entire axial length from the suction side 16 to the pressure side 1 in an eccentric thread-like manner, as in section 22 .

In the embodiment according to 1 the smooth section 20 of the shell 12 is cylindrical to the stator axis A with a constant outside diameter D. In the embodiment according to FIG 1 the outer diameter D of the smooth cylindrical section 20. The wall thickness of the inner part 14 between its inner surface 15 and its outer surface lying against the inner surface of the casing 12 is at least approximately constant in the threaded section 22 of the casing 12, while it is at least approximately constant in the cylindrical smooth section 20 of the casing 12 varies according to the thread form of the inner surface 15. The minimum inner diameter d and the maximum inner diameter e of the inner surface 15 of the inner part 14 are each axially constant along the stator axis A.

In the exemplary embodiment of a stator 10 according to FIG 2 is again as in the embodiment according to 1 a cylindrical smooth portion 20 of the shell 12 is provided and a subsequent threaded portion 22, and again the smooth cylindrical portion 20 and the threaded portion 22 of the shell 12 have the same maximum outside diameter D. In contrast to 1 However, if viewed in the axial direction of the stator axis A in the conveying direction F, the minimum inner diameter of the inner surface 15 of the inner part 14 is not constant, but instead increases in the conveying direction F from the suction side 16 to the pressure side 18 from a minimum inner diameter d1 on the suction side 16 over a between arranged minimum inner diameter d2 at the transition between smooth section 20 and threaded section 22 to an even smaller minimum inner diameter d3 at the pressure side 18, where d1>d2> d3. The same applies to the maximum inside diameters e1, e2 and e3.

In the exemplary embodiments of a stator 10 according to FIG 3 is now different from 1 and 2 a jacket 12 is provided, which decreases in a now conically designed smooth section 20 from a maximum outer diameter D1 on the suction side 16 to a smaller maximum outer diameter D2. This smaller maximum outer diameter D2 remains constant in the threaded section 22 of the casing 12 axially to the stator axis A up to the pressure side. The minimum inner diameter d or the maximum inner diameter e of the inner surface 15 of the inner part 14 remains in accordance with FIG 3 constant over the entire axial length from the suction side 16 to the pressure side 18.

In the embodiment according to 4 and 5 the eccentric shape of the internal thread of the stator 10 is shown in more detail. According to this embodiment 4 and 5 is in accordance with the embodiment 1 comparable. The eccentricity of the thread-shaped inner surface 15 of the inner part 14 is particularly evident in two different inner diameters of the inner contour measured perpendicular to one another in the cross section perpendicular to the stator axis A, namely a maximum inner diameter that 1 and 5 denoted by e, and the minimum inner diameter d, as in 1 and 5 . The inner diameter varies or oscillates with the pitch of the thread, axially or in longitudinal section tion, is therefore identical again after a thread pitch, as in 1 to recognize.

As in 5 shown, which can be obtained from a cross section of the inner part 14 perpendicular to the stator axis A (in 5 at the end or the end face 14A of the inner part 14) resulting inner contour of the inner part 14 on the inner surface 15 should preferably be stadium-shaped with two semicircular contour sections 15A and two parallel straight contour sections 15B connecting the contour sections 15A and spaced apart from one another, the distance between the straight Contour sections 15B and the corresponding diameter of the semicircular contour sections 15A as the smallest inner diameter d of the inner surface 15 is matched to the (outer) diameter of the circular rotor cross section of the rotor 30 . Such a stadium-shaped inner contour of the inner surface 15 of the stator 10 is already known per se from the prior art, as described above.

In the eccentrically-threaded section 22, the jacket 12 follows, both on the outer surface and on the inner surface of the jacket 12, the eccentrically-threaded inner surface 15 of the inner part 14 at least approximately or according to a close correlation or is adapted to the eccentrically-threaded shape of the inner surface 15 of the inner part 14 at least approximately adapted or mapped to this.

In an advantageous embodiment, the outer contour of the jacket 12 follows practically parallel to the inner contour of the inner part 14, so it is in particular also designed in the shape of a stadium.

However, the adjustment allows certain deviations from the exact shape, e.g. there does not have to be an exactly scaled (mathematically stretched) adjustment with contours that are exactly parallel to one another. In most embodiments, it is sufficient if the largest outer dimension a and the smallest outer dimension b of the eccentric outer wall of the jacket 12 lie or run in the same mutually orthogonal directions as the maximum inner dimension e and the minimum inner dimension d of the threaded inner surface 15 of the inner part 14.

For example, the outer surface or outer contour of the inner part 14, which bears against the inside of the casing 12, does not have to run exactly parallel to the, in particular stadium-shaped, inner surface 15 or inner contour of the inner part 14, although this is of course also possible.

Rather, an embodiment as in 4 and 5 shown expediently, in which, in cross section perpendicular to the stator axis A, the or a stadium-shaped inner contour of the inner part 14 on the inner surface 15 is reflected in a convexly curved and eccentric, in particular oval or at least approximately elliptical, outer contour of the inner part 14 on the outer surface or in this transitions to the outside. In this case, therefore, the outer contour of the jacket 12 is curved outwards or convexly over the entire circumference and has no straight sections corresponding to the sections 15B.

The inner contour or inner surface of the casing 12 resting against the outer contour or outer surface of the inner part 14 essentially corresponds to the outer contour or outer surface of the inner part 14. The outer contour or outer surface of the casing 12 thus also forms the outer contour or outer surface of the inner part 14, as shown, if the shell wall thickness remains constant, ie the inner surface and outer surface of the shell 12 run essentially parallel to one another. However, the adaptation can also take place in a different way, e.g. also with parallel outer contours of the inner part 14 and the jacket 12 that are only offset parallel to the inner contour or the cross section of the inner surface 15 or are mathematically stretched.

According to the invention, the jacket wall of the jacket 12 does not transition into a cylindrical connection area or flanging area for connection or flanging to a cylindrical counterpart on a pressure flange or a hose, in contrast to the prior art on the pressure side 18 .

Rather, according to the invention, as in 1 until 5 and 8th and 9 shown, the threaded portion of the jacket 12 and the inner part, ie the eccentrically threaded portion 22 and the inner surface 15 eccentrically threaded inner part 14 in a plane perpendicular to the stator axis A separated or severed. As a result, the thread cross section perpendicular to the stator axis A results in a non-cylindrical, eccentric or eccentric connection area 13 with a corresponding outer surface (and inner surface) formed by the threaded section 22 of the casing 12 .

Depending on the shape of the jacket 12, the connection area 13 is designed with an eccentricity in the threaded section 22, ie it has a larger diameter in a direction corresponding to the greatest extent of the eccentric thread than in the direction lower thereto right direction. Such an eccentric shape can in particular be at least approximately oval or elliptical or stadium-shaped.

This eccentric or provided with eccentricity terminal area 13 is slightly better in the views of FIG 4 and 5 to recognize.

The outer wall of the casing 12 in the threaded section 22 approximately reproduces this eccentricity and has a larger diameter a and a smaller diameter b in the cross section perpendicular to the stator axis A, as in FIG 4 to recognize and in 5 drawn. The larger the ratio a/b, the greater the eccentricity.

However, a slightly modified shape of the jacket 12 can also be selected in the connection area 13 than in the rest of the threaded section 22.

In 5 The rotor 30 is also shown inside the stator 10 and you can also see the already described eccentricity of the inner contour in the threaded inner surface 15 of the inner part 14 with the inner diameters d and e for the eccentric movement of the rotor 30.

the inside 6 and 7 as well as in 8th and 9 The pressure flange 40 shown has a receiving area 41 for the connection area 13 of the stator 10 . The receiving area 41 is formed with a recess in the pressure flange 40 , in particular in a flange surface 44 . The receiving area 41 or its recess has an inner wall 41A which surrounds a support surface 41C or delimits it on the outside. The support surface 41C of the receiving area 41 is lower than the flange surface 44 by a predetermined axial dimension. The inner wall 41A has, as in FIG 7 shown, a shape and eccentricity adapted to the outer wall of the connection area 13 of the stator 10, so that a positive connection or a positive insertion of the connection area 13 of the stator 10 into the receiving area 41 or its recess is made possible. The inner wall 41A of the receiving area therefore has a larger inner diameter a than the larger outer diameter of the jacket wall of the jacket 12 in the connection area 13 of the stator 10 and correspondingly a smaller inner diameter b corresponding to the smaller outer diameter of the connection area 13 in mutually perpendicular directions or coordinates (cf. 5 and 7 ).

To connect the pressure flange 40 to the stator 10, the connection area 13 of the stator 10 is inserted or plugged into the receiving area 41 of the pressure flange 40 and the outer wall of the casing 12 in the connection area 13 comes to rest positively against the inner wall 41A of the receiving area 41 of the pressure flange 40. A form-fitting contact only in sections is sufficient, but the two surfaces 41A and the outer wall of the jacket 12 preferably rest against one another over the entire circumference. When the pressure flange 40 is mounted, the central axis of the receiving area 41 and the inner wall 41A coincides with the stator axis A of the stator 10 due to the adjustment by the positive fit.

During this insertion movement, an end face 12A of the jacket 12 of the connection area 13 of the stator 10 comes to rest axially or is supported on the support surface 41C of the receiving area 41.

Stator 10 and pressure flange 40 are connected or braced to one another via fastening holes 45, in particular by means of a holding frame (not shown), which can include tie rods.

Within the inner wall 41A, starting from the support surface 41C, a lower web 41B runs upwards on the pressure flange 40, which is now shown in accordance with FIG 6 and 7 and 8 and 9 into face 14A of inner member 14 and provide a seal.

In addition, the end face 14A of the inner part 14 in the connection area 13 or on the pressure side 18, viewed axially to the stator axis A, can protrude or protrude by a small amount, for example a few millimeters, beyond the end face 12A of the casing 12, as best shown in 1 until 3 can be seen. As a result, the inner part 14 can also be slightly pretensioned by means of the web 41B, which additionally strengthens the sealing effect.

The form fit between the eccentric connection area 13 on the stator 10 and the corresponding eccentric receiving area 41 on the pressure flange 40 according to the invention results in a very stable and additionally torsion-proof connection between the stator 10 and the pressure flange 40.

The existing in the prior art outwardly projecting and usually welded anti-rotation pin on the outside of the stator and the need to mount this anti-rotation pin in a predetermined stop position on the support frame can thus be omitted.

In addition, no additional cylindrical connection area has to be attached or molded onto the casing wall of the stator. Rather, in a simplified production process, a plurality of stators can be made by cutting a longer blank to length, which is already (also) provided with the described thread shape on its outside.

Furthermore, the outlet areas for the flowable medium on the pressure side 18 are firmly defined as angular areas or segments due to the eccentric or non-circular cross section, which also allows the internal geometry of the pressure flange to be further optimized in terms of flow technology.

In a further embodiment, not shown, with a three-start or four-start thread on the inner surface of the inner part of the stator, the inner contour is correspondingly of a regular polygonal basic shape, namely at least approximately triangular in the case of a three-start thread and at least approximately square or rectangular in the case of a four-start thread. The connection section of the stator and the receiving area on the pressure flange then have a corresponding polygonal basic shape. The corners of the polygonal basic shape are convexly rounded according to the outer diameter of the rotor cross section, so that the rotor can support or rest with its cross section in a circumferential movement on the rounded corner areas of the inner contour of the inner part.

In an embodiment that is not shown, the pressure flange includes a receiving area for the connection area of the stator, wherein the receiving area has an outer wall and a support surface at least partially surrounding the outer wall, and the outer wall of the receiving area has a shape that is adapted at least in sections to the inner surface of the connection area of the stator. so that a form-fitting connection or a form-fitting insertion of the connection area of the stator into the receiving area of the pressure flange is made possible, with an end face of the jacket in the connection area of the stator being supported or able to be supported on the support surface of the receiving area of the pressure flange. In addition to the outer wall or as an alternative to the outer wall, the inner wall of the casing is provided in the connection area for the form-fitting connection.

Reference List

10

stator

12

Coat

13

connection area

13A

support surface

14

inner part

14A

face

15

Inner surface

15A, 15B

inner contour section

16

suction side

18

pressure side

20

smooth section

22

thread section

30

rotor

32

outer surface

40

pressure flange

41

form-fitting recording

41A

outer wall

41B

web

41C

support surface

42

exhaust port

43

entry opening

44

flange face

45

mounting holes

48

exit port

A

stator axis

a

large diameter

b

small diameter

d, d1

inner diameter

d2, d3

inner diameter

e, e1

inner diameter

e2, e3

inner diameter

D

outer diameter

D1, D2

outer diameter

f

conveying direction

R

rotation

Claims (12)

Stator (10) for an eccentric screw pump for conveying a flowable medium, in particular mortar, plaster or another flowable or pasty building material mixture, the stator (10) a) being provided for receiving a snail-shaped rotor, b) a casing (12). at least one rigid material, in particular metal, and an inner part (14) made of at least one elastic material, in particular special elastomer, and c) has a stator axis (A), d) wherein an inner surface (15) of the inner part (14) is formed with a, in particular double or multiple thread, and e) wherein the jacket (12) on a pressure-side and/or front end (18) forms or has a connection area (13) for connection to a pressure line or a pressure flange (40), f1) the outer surface or outer contour and/or the inner surface or inner contour of the jacket (12) in the connection area (13) at least approximately reproduces the inner surface (15) or inner contour of the inner part or at least approximately follows the thread, in particular two or more threads, of the inner part (14) or f2) the casing (12) having a cross section in the connection area (13). perpendicular to the stator axis (A), which is either eccentric, especially in the case of a two-start thread on the inner surface (15), ie has outside diameters (a, b) of different sizes in two mutually orthogonal directions, or one, especially in the case of a three-start thread Thread on the inner surface (159), triangular basic shape or, in particular with a four-start thread on the inner surface (15), quadrangular basic shape, each with rounded convex corner areas. stator after claim 1 , in which the outer surface or the outer contour and/or the inner surface or inner contour or the cross section of the jacket (12) in the connection area (13) has an oval or elliptical or stadium-like or bone-shaped shape and/or is at least partially convexly curved. Stator according to one of the preceding claims, in which the outer surface or the outer contour and/or the inner surface or inner contour or the cross section of the casing (12) in the connection area (13) is essentially at the same radial distance or parallel to the inner surface or inner contour or the Cross section of the inner part (14) runs. Stator according to one of the preceding claims, in which the outer surface or the outer contour and/or the inner surface or inner contour or the cross section of the casing (12) in the connection area (13) is at a varying radial distance from the inner surface or inner contour or the cross section of the inner part (14) runs, for example has an oval shape with a stadium-shaped inner surface or inner contour or stadium-shaped cross-section of the inner part (14). Stator according to one of the preceding claims, in which the casing (12) has a thread-shaped section (22) on its outer surface and/or its inner surface or in its cross section, at least over an axial partial area, preferably over the entire axial length, which in its course is adapted to the thread of the inner surface (15) of the inner part (14), and in which the connection area (13) is a pressure-side and/or front-side end area of the threaded section (22) of the jacket and/or the cross section of the outer wall or inner wall of the connection area corresponds to a cross section through the jacket (12) in the threaded section (22) of its outside and/or is produced by cutting to length or cutting transversely to the stator axis (A) in the threaded section (22). stator after claim 5 , in which the threaded section (22) of the jacket (12) either also extends over its entire axial length along the stator axis (A) or only over an axial partial area, to which a smooth section (20 ) of the casing (12), wherein the casing (12) is in particular cylindrical or conical in the smooth section (20) and/or wherein in particular the maximum outer diameter of the casing (12) in the threaded section (22) is essentially constant and /or in particular wherein the maximum outside diameter of the jacket (12) in the smooth section (20) is either constant and corresponds to the maximum outside diameter (D) of the jacket (12) in the threaded section (22) or from a larger maximum outside diameter (D1). the suction side (16) to a smaller maximum outside diameter (D2) at the transition to the threaded section (22) of the shell (12). Stator according to one of the preceding claims, having at least one of the following features: a) an outside of the inner part (14) rests at least predominantly on an inside of the casing (12), b) the mean or the smallest inner diameter (d, d1, d2, d3) of the thread on the inner surface (15) of the inner part (14) is constant axially to the stator axis (A) or is larger on the suction side (16) than on the pressure side (18), c) the inner surface (15) of the inner part (14) has the thread over its entire axial length along the stator axis (A), d) The casing (12) and inner part (14) are designed as hollow bodies along the stator axis (A). Method for manufacturing a plurality of stators according to one of the preceding claims, in which a) an elongate blank is provided, wherein the blank has a continuous blank inner part and a continuous blank casing surrounding the blank inner part, wherein the inner surface of the blank inner part and the outer surface of the blank casing have a blank thread corresponding to the thread provided for the respective inner parts (14) and the respective casings (12) of the stators, b) the stators (10) with their connection areas (13) are produced by cutting the elongated blank to the desired axial lengths of the stators (10). Eccentric screw pump for conveying a flowable medium, in particular a flowable building material mixture such as mortar or plaster, which has a stator (10) according to one of Claims 1 until 8th and a helical rotor (30) arranged in the stator (10) and a pressure flange (40) or pressure line connected to the connection area (13) of the stator (10). progressing cavity pump claim 9 , in which the pressure flange (40) comprises a receiving area (41) for the connection area (13) of the stator (10), which has an inner wall (41A) and a support surface (41C) at least partially surrounded by the inner wall (41A), wherein the inner wall (41A) has a shape adapted at least in sections to the outer surface of the connection area (13) of the stator (10), so that a form-fitting connection or a form-fitting insertion of the connection area (13) of the stator (10) into the receiving area (41) of the pressure flange (40), one end face (12A) of the casing (12) being supported or capable of being supported in the connection area (13) of the stator (10) on the support surface (41C) of the receiving area (41). progressing cavity pump claim 9 , in which the pressure flange comprises a receiving area for the connection area of the stator, the receiving area having an outer wall and a support surface at least partially surrounding the outer wall, the outer wall of the receiving area having a shape adapted at least in sections to the inner surface of the connection area of the stator, so that a form-fitting connection or a form-fitting insertion of the connection area of the stator into the receiving area of the pressure flange is made possible, with an end face of the jacket in the connection area of the stator being supported or able to be supported on the support surface of the receiving area of the pressure flange. progressing cavity pump claim 10 or claim 11 , in which the pressure flange (40) in the receiving area (41) has a web (41B) which preferably runs within the inner wall (41A) and/or is preferably lower starting from the support surface (41C) and which is located on the end face (14A) of the Inner part (14) of the stator (10) in the connection area (13) rests or presses in a sealing manner.

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