Magnetic coupling pump assembly

Abstract

The invention relates to a magnetic coupling pump assembly, comprising: an interior (11) formed by a pump housing (2) of the pump assembly; a can (10) which has a central longitudinal axis (B) and hermetically seals a chamber (12) enclosed by the can with respect to the interior (11) formed by the pump housing (2); an impeller shaft (13) which can be driven in rotation about an axis of rotation (A); an impeller (16) which is mounted on one end of the impeller shaft (13); an inner rotor (17) which is mounted on the other end of the impeller shaft (13) and bears a plurality of magnets (18); and an outer rotor (24) which is mounted on a drive shaft (20), interacts with the inner rotor (17) and bears a plurality of magnets (23). According to the invention, two magnets (23) of the outer rotor (24) which are adjacent in the axial direction are offset in the circumferential direction by an offset (V), wherein an imaginary line (LV) extending through identical corner points of each of two axially adjacent magnets (23) and an imaginary line (L) extending in parallel with the axis of rotation (A) form an offset angle (α).

Description

[0001] Description

[0002] Magnetic coupling pump arrangement

[0003] The invention relates to a magnetic coupling pump arrangement with an interior space formed by a pump housing of the pump arrangement, a containment shell with a central longitudinal axis, which hermetically seals a chamber enclosed by it from the interior space formed by the housing, an impeller shaft which can be driven rotatably about an axis of rotation, an impeller arranged at one end of the impeller shaft, an inner rotor arranged at the other end of the impeller shaft and carrying a plurality of magnets, an outer rotor arranged on a drive shaft, interacting with the inner rotor and carrying a plurality of magnets.

[0004] Such sealless pumps are used in particular for pumping dangerous or toxic media in order to prevent leakage, since, depending on the medium, even small quantities of the pumped medium can have life-threatening consequences.

[0005] In such pumps, the rotating magnetic field induces eddy currents in the metallic containment shell located between the inner and outer rotors. This statically positioned containment shell, together with the housing cover and the pump housing itself, forms the pressure-bearing pump section, ensuring that the inner rotor located within this shell is in constant contact with the pumped medium. To reduce eddy currents and prevent the associated continuous heating of the medium, even to the point of evaporation, metallic containment shell materials with high electrical resistance are commonly used. Particularly expensive nickel-based alloys have proven to be the preferred choice for this purpose.

[0006] The object of the present invention is to provide a pump arrangement, in particular a magnetic coupling pump arrangement, in which the eddy current losses in the containment shell in the region of the magnets are reduced.

[0007] The object of the invention is achieved by arranging two axially adjacent magnets of the outer rotor offset circumferentially by an offset angle. An imaginary line extending through the same corner point of two axially adjacent magnets and an imaginary line running parallel to the axis of rotation enclose an offset angle. Due to the staggered arrangement of the magnets, the eddy currents flow obliquely through the containment shell. The associated lengthening of the eddy current path increases the resistance. As a result, the eddy current in the containment shell is reduced, thereby reducing eddy current losses.

[0008] Advantageously, two axially adjacent magnets of the inner rotor are arranged offset in the circumferential direction. The offset arrangement of the inner rotor magnets compensates for the reduction in the maximum transmittable torque caused by the axially varying load angle.

[0009] In a further embodiment, both the outer rotor and the inner rotor, or just one of the two rotors, can be constructed modularly using a plurality of axially successive annular partial outer rotors or partial inner rotors. The individual magnets are attached to the respective partial rotor, and the offset angle between the axially adjacent magnets results from the offset of the axially adjacent partial rotors. For easy assembly of the partial rotors, each of the partial outer rotors orPartial inner rotors have a first end face and a second end face opposite the first end face, wherein a plurality of through holes extend substantially parallel to the axis of rotation from the first end face through the respective partial rotors to the second end face, wherein a rod extends through each of the through holes, wherein the respective partial rotors are braced against one another via the rods by suitable means.

[0010] In a further advantageous embodiment, the offset and thus the offset angle are alternately clockwise and counterclockwise along the axial direction, i.e., in a zigzag configuration. This lengthens the eddy current path and compensates for the additional axial forces caused by the skew.

[0011] It has proven particularly advantageous to provide the outer surface of the containment shell with a plurality of elevations, wherein the outer surface is substantially wave-shaped, each having a plurality of wave peaks and wave troughs, and the elevations are arranged obliquely with respect to the imaginary line extending parallel to the axis of rotation on the outer surface, wherein the elevations or an imaginary line corresponding to the course of the elevations and the line enclose an angle, and that the line corresponding to the course of the elevations and the line extending through an identical corner point of two axially adjacent magnets enclose an angle of substantially 45° to substantially 135°, in particular substantially 90°.

[0012] It has proven particularly advantageous if the inclined elevations in or near the center of the cylindrical part of the containment shell undergo a reversal of direction, such that a substantially mirrored course of the elevations is created, and the magnets of the outer rotor are arranged offset in the opposite direction. The advantage of this is that this lengthens the eddy current path and compensates for the additional axial forces caused by the inclination. Embodiments of the invention are illustrated in the drawings and are described in more detail below. They show:

[0013] Fig. 1 is a longitudinal section through a magnetic coupling pump arrangement according to the prior art,

[0014] Fig. 2 a three-dimensional representation of an arrangement consisting of inner rotor, containment shell and outer rotor,

[0015] Fig. 3 is a schematic representation of an inventive arrangement of the magnets of the inner rotor and the outer rotor,

[0016] Fig. 4 is a schematic representation of an eddy current path running in the containment shell with conventionally arranged magnets,

[0017] Fig. 5 is a schematic representation of an eddy current path running in the containment shell in an exemplary arrangement of the magnets according to the invention,

[0018] Fig. 6 a section through an inventive arrangement of inner rotor, containment shell and outer rotor,

[0019] Fig. 7 a three-dimensional representation of another arrangement, consisting of inner rotor, containment shell and outer rotor,

[0020] Fig. 8 is a detailed view of the arrangement shown in Fig. 7,

[0021] Fig. 9 is a further detailed view of the arrangement shown in Fig. 7,

[0022] Fig. 10 is a detailed view of an alternative arrangement, consisting of inner rotor, containment shell and outer rotor, Fig. 11 is a detailed view of another alternative arrangement, consisting of inner rotor, containment shell and outer rotor,

[0023] Fig. 12 is a schematic representation of an arrangement according to the invention of the magnets of the outer rotor in a containment shell with elevations on the outer surface,

[0024] Fig. 13 is a sketch of an inventive arrangement of the magnets of the outer rotor to the elevations according to Fig. 12,

[0025] Fig. 14a and 14b a simplified sketch of an inventive arrangement of the magnets of the outer rotor with a further variant of the containment shell.

[0026] Figure 1 shows an example of a pump assembly 1 in the form of a magnetic coupling pump assembly, as is known from the prior art. The pump assembly 1 has a multi-part pump housing 2 of a centrifugal pump, which comprises a hydraulic housing 3 designed as a spiral housing, a housing cover 4, a bearing support lantern 5, a bearing support 6, and a bearing cover 7.

[0027] The hydraulic housing 3 has an inlet opening 8 for sucking in a pumped medium and an outlet opening 9 for expelling the pumped medium. The housing cover 4 is arranged on the side of the hydraulic housing 3 opposite the inlet opening 8. The bearing support lantern 5 is attached to the side of the housing cover 4 facing away from the hydraulic housing 3. The bearing support 6 is attached to the side of the bearing support lantern 5 opposite the housing cover 4. The bearing cover 7 is in turn attached to the side of the bearing support 6 facing away from the bearing support lantern 5.

[0028] A containment shell 10 is attached to the side of the housing cover 4 facing away from the hydraulic housing 3 and extends at least partially through an interior space 11 defined by the pump housing 2, in particular by the housing cover 4, by the bearing support lantern 5, and by the bearing support 6. The containment shell 10 hermetically seals a chamber 12 enclosed by it from the interior space 11.

[0029] An impeller shaft 13 rotatable about a rotation axis A extends from a flow chamber 14 defined by the hydraulic housing 3 and the housing cover 4 through an opening 15 provided in the housing cover 4 into the chamber 12.

[0030] An impeller 16 is attached to one end of the impeller shaft 13 located within the flow chamber 14. An inner rotor 17 is arranged within the chamber 12 at the opposite end of the shaft. The inner rotor 17 is equipped with several magnets 18, which are arranged on the side of the inner rotor 17 facing the containment shell 10.

[0031] Between the impeller 16 and the inner rotor 17 there is arranged a bearing arrangement 19 which is operatively connected to the impeller shaft 13 which can be driven to rotate about the axis of rotation A.

[0032] A drive motor (not shown), preferably an electric motor, drives a drive shaft 20. The drive shaft 20, which can be driven rotatably about the axis of rotation A, is arranged essentially coaxially with the impeller shaft 13. The drive shaft 20 extends through the bearing cover 7 and the bearing bracket 6 and is mounted in two ball bearings 21, 22 accommodated in the bearing bracket 6. An outer rotor 24 carrying a plurality of magnets 23 is arranged at the free end of the drive shaft 20. The magnets 23 are arranged on the side of the outer rotor 24 facing the containment shell 10. The outer rotor 24 extends at least partially over the containment shell 10 and interacts with the inner rotor 17 in such a way that the rotating outer rotor 24 also sets the inner rotor 17 and thus the impeller shaft 13 and the impeller 16 in a rotational movement by means of magnetic forces.

[0033] The arrangement according to the invention of inner rotor 17, single-walled containment shell 10, and outer rotor 24, shown in an enlarged view in Fig. 2, is intended for installation in the pump assembly 1 shown in Fig. 1 as an example of various magnetic coupling pump assemblies. The inner rotor 17 has a plurality of magnets 18 arranged on the side facing the containment shell 10, particularly in the region of its cylindrical wall. The outer rotor is equipped with a plurality of magnets 23, which are also mounted facing the containment shell 10.

[0034] Fig. 3 shows a simplified sketch of a possible arrangement according to the invention of the magnets 18 of the inner rotor 17 and the magnets 23 of the outer rotor 24. For better understanding, the parts of the inner and outer rotors that support the magnets 18 and 23 have been omitted from the illustration. The containment shell 10 is sketched between the magnets 18 and 23 for orientation. It can be seen that two axially adjacent magnets 23 of the outer rotor 24 are arranged offset in the circumferential direction by an offset V. An imaginary line Lv extending through the same corner points 25, 25' of two axially adjacent magnets 23 and an imaginary line L running parallel to the axis of rotation A enclose an offset angle α. The offset angle α shown in the exemplary embodiment is 14.5°. The offset angle α is spanned by the line L in a clockwise direction.

[0035] The radial displacement is marked with V. In the exemplary embodiment shown, two axially adjacent magnets 18 of the inner rotor 17 are also offset by the same offset angle α. The magnets (23) of the outer rotor (24) and the magnets (18) of the inner rotor (17) are arranged such that, at least theoretically, they are or can be brought into surface overlap with one another, taking into account the different diameters of the outer rotor 24 and the inner rotor 17. However, it is also possible for only the axially adjacent magnets of a rotor, either the inner rotor 17 or the outer rotor 24, to be offset.

[0036] Fig. 4 schematically shows an eddy current path 26 running in the containment shell 10 with the magnets 18 of the inner rotor 17 and the magnets 23 of the outer rotor 24 arranged in a known manner. Fig. 5 schematically shows an eddy current path 26' with the magnets 18 of the inner rotor 17 and the magnets 23 of the outer rotor 24 arranged offset according to the invention. It can be seen that the eddy current path 26' running in the containment shell 10 has a longer eddy current path than the eddy current path 26 shown in Fig. 4. The eddy currents induced in the containment shell 10, or more precisely in its wall, thus have an oblique course.

[0037] Fig. 6 shows a section through the arrangement of inner rotor 17, containment shell 10 and outer rotor 24 according to Fig. 2, wherein the radial offset V in the outer rotor is shown.

[0038] In the embodiment of Fig. 7, the inner rotor 17 is constructed in a modular manner by a plurality of axially successive annular partial inner rotors 17a, 17b, 17c, and 17d. In conjunction with Fig. 8, in which essentially only the magnets 23 of the outer rotor 23 are shown for the sake of clarity, it can be seen that the outer rotor 24 is formed by a plurality of axially successive annular partial outer rotors 24a, 24b, 24c, and 24d. The partial inner rotors 17a to 17d or partial outer rotors 24a to 24d can be arranged rotated relative to one another as desired in order to produce the offset V of the magnets 18 and 23 described for Figs. 3 and 6. It is evident that, if required, it is possible to manufacture only one of the rotors 17 or 24 using partial rotors 17a to 17b or 24a to 24b.

[0039] Fig. 9 shows, by way of example, how the outer rotor 24, assembled from the partial outer rotors 24a to 24d in Fig. 7 and Fig. 8, is constructed, wherein only the partial outer rotors 24c and 24d are shown in Fig. 9. Each of the partial outer rotors 24a to 24d has a first end face 27 and a second end face 28 opposite the first end face 27. A plurality of through holes 29 extend through the partial outer rotors 24a to 24d, essentially parallel to the axis of rotation A, from the first end face 27 to the second end face 28.

[0040] Rods 30 extend through the through-holes 29, with one rod 30 extending through each of the partial outer rotors 24a to 24d. The partial outer rotors 24a to 24d can be clamped against one another using suitable means (not shown). The rods 30 can be designed, for example, as threaded rods or at least be provided with a thread at their free ends, so that the partial outer rotors 24a to 24d can be clamped against one another by screwing on threaded nuts. The rods 30 can also be designed, for example, as rivets. It is clear that the inner rotor 17 can be constructed in the same way.

[0041] In addition to the through holes 29 shown, further through holes 29 can be provided which are spaced apart from one another in such a way that the desired offset V can be produced by rotating the corresponding partial rotor 17a to 17d or 24a to 24d about the axis of rotation A and then sliding it onto the rods 30.

[0042] In addition to the rotation around the rotation axis A of the adjacent sub-rotors, an additional rotation of 180° around a vertical axis marked X is also possible, which further increases the number of possible offset angles a.

[0043] Fig. 10 and Fig. 11 show further embodiments of the invention in which the offset V and thus the offset angle a are selected alternately clockwise and counterclockwise along the axial direction, whereby the eddy current path is extended and the axial forces additionally occurring due to the skew are compensated.

[0044] In the embodiment of Fig. 10, the offset from partial outer rotor 24a to partial outer rotor 24b has a different amount than the offset from partial outer rotor 24b to partial outer rotor 24c. The offset from partial outer rotor 24c to partial outer rotor 24d has a different, in this case larger, amount than the offset from partial outer rotor 24a to partial outer rotor 24b and partial outer rotor 24b to partial outer rotor 24c.

[0045] In the embodiment of Fig. 11, the offset V of the partial outer rotor 24a to

[0046] Partial outer rotor 24b has the same amount as the offset from partial outer rotor 24b to partial outer rotor 24c and the offset from partial outer rotor 24c to partial outer rotor 24d. Thus, the amount of the offset angle a of two axially adjacent magnets 23 of the outer rotor 24 is the same.

[0047] Fig. 12 shows a simplified sketch of a possible arrangement of the magnets 23 of the outer rotor 24 according to the invention. For clarity, the parts of the outer rotor that support the magnets 23 have been omitted from the illustration. In the embodiment shown, the containment shell 10 has an outer surface 31 with a plurality of elevations 32. The outer surface 31 is essentially wave-shaped, each with a plurality of wave peaks 33 and wave troughs 34. Channel-like cavities (not shown) can extend through the elevations 32.

[0048] In the area of ​​the magnets 23, the elevations 32 are designed in a screw-like or spindle-like manner, i.e., the elevations 32 are arranged obliquely with respect to an imaginary line L on the outer surface 31 extending parallel to the axis of rotation A. In the embodiment shown, the elevations 32 or an imaginary line designated LE that corresponds to the course of the elevations 32 and the line L form an angle ß of 45°. The angle ß is spanned counterclockwise by the line L. The angle ß can range from greater than 0° to less than 90°. Preferably, the angle ß is in a range from 30° to 70°. An imaginary line Lv extending through the corner points of two axially adjacent magnets 23 and the line L form an offset angle α of 14.5°.

[0049] The offset angle a is spanned by the line L in a clockwise direction.

[0050] It has proven particularly advantageous if the line LE and the line Lv form an angle <p von im Wesentlichen 90° einschließen, wie in der Fig. 13 gezeigt.

[0051] Figs. 14a and 14b each show a schematic representation of another possible arrangement of the magnets 23 of the outer rotor 24 according to the invention. The obliquely extending elevations 32 undergo a reversal of direction in or near the center of the cylindrical part of the containment shell 10, such that an essentially mirrored configuration of the elevations 32 is created. Accordingly, the magnets 23 are arranged offset in opposite directions. The invention has been explained using examples in which the number of axially adjacent magnets 17 and 23 is three or four. In fact, the number of axially adjacent magnets 17 and 23 can be higher.

Claims

Patent claims 1. Magnetic coupling pump arrangement with - an interior space (11) formed by a pump housing (2) of the pump arrangement, - a containment shell (10) with a central longitudinal axis (B), which hermetically seals a chamber (12) enclosed by it from the interior space (11) formed by the housing (2), - an impeller shaft (13) rotatably driven about an axis of rotation (A), - an impeller (16) arranged at one end of the impeller shaft (13), - an inner rotor (17) arranged at the other end of the impeller shaft (13) and carrying a plurality of magnets (18), - an outer rotor (24) arranged on a drive shaft (20), interacting with the inner rotor (17) and carrying a plurality of magnets (23), characterized in that two axially adjacent magnets (23) of the outer rotor (24) are arranged offset in the circumferential direction by an offset (V), wherein an imaginary line (Lv) extending through an identical corner point of two axially adjacent magnets (23) and an imaginary line (L) running parallel to the axis of rotation (A) enclose an offset angle (a).

2. Magnetic coupling pump arrangement according to claim 1, characterized in that two axially adjacent magnets (18) of the inner rotor (17) are arranged offset in the circumferential direction by an offset (V), wherein an imaginary line, each passing through an identical corner point of two axially adjacent Magnets (23) extending line (Lv) and an imaginary line (L) running parallel to the axis of rotation (A) enclose an offset angle (a).

3. Magnetic coupling pump arrangement according to claim 1 or 2, characterized in that the outer rotor (24) is constructed in a modular manner by a plurality of axially successive annular partial outer rotors (24a, 24b, 24c, 24d).

4. Magnetic coupling pump arrangement according to one of claims 1 to 3, characterized in that the inner rotor (17) is constructed in a modular manner by a plurality of axially successive annular partial inner rotors (17a, 17b, 17c, 17d).

5. Magnetic coupling pump arrangement according to claim 3 or 4, characterized in that each partial outer rotor (24a, 24b, 24c, 24d) or partial inner rotor (17a, 17b, 17c, 17d) has a first end face (27) and a second end face (28) opposite the first end face (27), wherein a plurality of through holes (29) extend substantially parallel to the axis of rotation (A) from the first end face (27) through the respective partial rotors (17a, 17b, 17c, 17d, 24a, 24b, 24c, 24d) to the second end face (28).

6. Magnetic coupling pump arrangement according to claim 5, characterized in that a rod (30) extends through each of the through holes (29), wherein the respective partial rotors (17a, 17b, 17c, 17d, 24a, 24b, 24c, 24d) are braced against one another via the rods (30) by suitable means.

7. Magnetic coupling pump arrangement according to one of claims 3 to 6, characterized in that along the axial direction the offset (V) and thus the offset angle (α) is selected alternately clockwise and counterclockwise.

8. Magnetic coupling pump arrangement according to one of the preceding claims, characterized in that the containment shell (10) has an outer surface (31) with a plurality of elevations (32), wherein the outer circumferential surface (31) is substantially wave-shaped, each having a plurality of wave peaks (33) and wave troughs (34), and the elevations (32) are arranged obliquely with respect to the imaginary line (L) extending parallel to the axis of rotation (A) on the outer circumferential surface (31), wherein the elevations (32) or an imaginary line (LE) corresponding to the course of the elevations (32) and the line (L) enclose an angle (β), and that the line (LE) corresponding to the course of the elevations (32) and the line (Lv) extending through an identical corner point of two axially adjacent magnets (23) enclose an angle (α) of substantially 45° to 135°, in particular substantially 90°.

9. Magnetic coupling pump arrangement according to claim 8, characterized in that the obliquely extending elevations (32) experience a reversal of direction in or near the center of the cylindrical part of the containment shell (10) such that a substantially mirrored course of the elevations (32) is created, the magnets (23) being arranged offset in the opposite direction.

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