ELECTRIC CENTRIFUGAL PUMP WITH CONTAINMENT SHELL GROOVES

Abstract

An electric centrifugal pump having a motor housing, a pump head, a containment shell, and a rotor assembly consisting of a pump impeller and a permanent magnet rotor, wherein the pump head with the containment shell defines a wet chamber, in which the rotor assembly is arranged rotationally around a longitudinal motor axis, the containment shell with the motor housing defines a dry chamber, in which a wound stator is arranged, and the permanent magnet rotor is arranged within the stator and a hollow-cylindrical region of the containment shell. Particle accumulations in the region between the containment shell and the permanent magnet rotor cannot occur or can only occur to a very minor extent and that the consequences of impurities in the wet chamber are reduced in order to prevent premature wear or a blockage of the centrifugal pump.

Claims

1. An electric centrifugal pump having a longitudinal motor axis, the pump comprising: a motor housing; a pump head; a containment shell having a hollow cylindrical region with an inner circumference; a wet chamber defined by the pump head and the containment shell; a dry chamber defined by the motor housing and the containment shell; a stator arranged within the dry chamber, the stator having pole gaps; a rotor assembly consisting of a pump impeller and a permanent magnet rotor, the rotor assembly arranged in the wet chamber rotating around the longitudinal motor axis; and a permanent magnet rotor arranged within the stator and the hollow-cylindrical region of the containment shell, wherein the containment shell includes at the inner circumference one or more containment shell grooves, which are arranged parallel to the longitudinal motor axis and/or parallel to the pole gaps of the stator.

2. The electric centrifugal pump according to claim 1, wherein the containment shell grooves have an asymmetrical cross section.

3. The electric centrifugal pump according to claim 1, wherein the containment shell grooves comprise an undercut so that the width of the groove increases with increasing groove depth at least in sections.

4. The electric centrifugal pump according to claim 1, wherein the containment shell grooves have a cross section that changes over their groove length.

5. The electric centrifugal pump according to claim 1, wherein the cross section of at least one containment shell groove is semicircular.

6. The electric centrifugal pump according to claim 1, wherein the cross section of at least one containment shell groove is rectangular.

7. The electric centrifugal pump according to claim 1, wherein the cross section of at least one containment shell groove is triangular.

8. The electric centrifugal pump according to claim 1, wherein the cross section of at least one containment shell groove is trapezoidal.

9. The electric centrifugal pump according to claim 1, wherein at least one containment shell groove is sharp-edged.

10. The electric centrifugal pump according to claim 1, wherein the containment shell grooves are pitched in the same way in a pitched stator.

11. The electric centrifugal pump according to claim 10, wherein the stator comprises a claw pole stator and only every second pole gap has a containment shell groove aligned with it.

12. The electric centrifugal pump according to claim 1, wherein the depth of at least one containment shell groove is between 0.3 and 1.0 mm.

13. The electric centrifugal pump according to claim 1, further comprising a cooling rib parallel to the containment shell groove and positioned within a pole gap.

14. The electric centrifugal pump according to claim 1, further comprising: an annular protrusion extending coaxially to the longitudinal motor axis from the pump impeller into a chamber region within the containment shell, and an outer diameter of the annular protrusion is smaller than an inner diameter of the containment shell in the region of the protrusion.

15. The electric centrifugal pump according to claim 14, further comprising a protruding ring collar extending from the containment shell towards the pump impeller and the outer diameter of the annular protrusion is slightly smaller than the inner diameter of the protruding ring collar, and the annular protrusion and the protruding ring collar are arranged concentrically to one another and to the longitudinal motor axis.

16. The electric centrifugal pump according to claim 14, wherein the permanent magnet rotor has an outer diameter and the outer diameter of the annular protrusion is larger than or equal to the outer diameter of the permanent magnet rotor.

17. The electric centrifugal pump according to claim 15, wherein the protruding ring collar of the containment shell is at a very small distance from the pump impeller but does not touch the pump impeller.

18. The electric centrifugal pump according to claim 1, wherein the permanent magnet rotor has an outer surface that includes several rotor grooves.

19. The electric centrifugal pump according to claim 18, wherein the rotor grooves extend parallel to the longitudinal motor axis on the outer surface of the permanent magnet rotor.

20. The electric centrifugal pump according to claim 14, wherein the outer diameter of the annular protrusion is smaller than the inner diameter of the containment shell in the region of the permanent magnet rotor.

21. The electric centrifugal pump according to claim 1, further comprising a containment shell flange having a recess radially outside the protruding ring collar, which enlarges the recess distance to an impeller disk of the pump impeller.

22. The electric centrifugal pump according to claim 1, wherein the protruding ring collar tapers in the axial direction towards the pump impeller.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0019] The invention is better understood by reading the following Detailed Description of the Preferred Embodiments with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which:

[0020] FIG. 1 illustrates a section of a stator with a containment shell with a containment shell groove,

[0021] FIG. 2 is a spatial representation of a claw pole stator,

[0022] FIG. 3 illustrates a section of a containment shell with a first variant of the containment shell groove,

[0023] FIG. 4 illustrates a section of a containment shell with a second variant of the containment shell groove,

[0024] FIG. 5 illustrates a section of a containment shell with a third variant of the containment shell groove,

[0025] FIG. 6 illustrates a containment shell with pitched containment shell grooves,

[0026] FIG. 7 illustrates a containment shell with a direction of pitch opposite FIG. 6.

[0027] FIG. 8 is a sectional view through a centrifugal pump according to the invention,

[0028] FIG. 9 illustrates an enlarged section A of FIG. 8,

[0029] FIG. 10 is a spatial representation of a rotor assembly,

[0030] FIG. 11 is a front view of the rotor assembly,

[0031] FIG. 12 illustrates an enlarged section A of FIG. 11,

[0032] FIG. 13 is a top view of the rotor assembly,

[0033] FIG. 14 is a sectional view of the rotor assembly of FIG. 13,

[0034] FIG. 15 is a schematic representation of a containment shell, and

[0035] FIG. 16 is a sectional view of the containment shell.

[0036] Note: The reference symbols with apostrophe/index and the corresponding reference symbols without apostrophe/index refer to details with the same name in the drawings and the drawing description. This reflects use in another embodiment or the prior art, and/or the detail is a variant. For the sake of simplicity, the claims, the description introduction, the reference symbol list and the abstract contain only reference symbols without apostrophe/index.

DETAILED DESCRIPTION OF THE INVENTION

[0037] In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

[0038] FIG. 1 shows a section of a stator 4′ with pronounced poles, into which a containment shell 3′ is inserted. The containment shell 3′ comprises a containment shell groove 35′ and a cooling rib 38′, which is accommodated in a pole gap 51′. The cooling rib 38′ enlarges the surface of the containment shell 3′ and therefore improves the heat transfer from the stator winding (not shown) to the conveyed medium within the containment shell 3′. The containment shell groove 35′ extends in the region of the pole gap 51′ and has in this case a cross section in the shape of a semicircular disk.

[0039] FIG. 2 shows a spatial representation of a claw pole stator 52 with claw poles 53, containment shell grooves 35, and a winding intake space 54. The containment shell 3 has in this case been produced by injection molding around the claw poles 53, as a result of which the claw poles 53 partially form the containment shell 3. In every second pole gap 51, a containment shell groove 35 is formed. The illustrated containment shell grooves 35 are pitched parallelly to one another. The removal from the injection molding tool takes place by unscrewing. The cross section of the containment shell grooves 35 comprises a minimal surface at a first end of the axial extent and a maximal surface at its other end.

[0040] FIG. 3 shows a section of a containment shell 3″ with a first variant of the containment shell groove 35″ and the cooling rib 38″, where the cross section of the containment shell groove 35″ is substantially rectangular.

[0041] FIG. 4 shows a section of a containment shell 3′″ with a second variant of the containment shell groove 35′″ and the cooling rib 38′″, where the cross section of the containment shell groove 35′″ is substantially triangular. The cross section of the containment shell groove 35′″ is thus asymmetrical and largely holds particles in the preferential direction of rotation.

[0042] FIG. 5 shows a section of a containment shell 3″ with a third variant of the containment shell groove 35′″ and the cooling rib 38″, where the cross section of the containment shell groove 35′″ is substantially trapezoidal with an undercut. In this case, particles are largely held independently of the direction of rotation.

[0043] FIG. 6 shows a containment shell 3a with pitched containment shell grooves 35a, a containment shell flange 22a, screw holes 27a, and a mount 34a for an axis component. The containment shell grooves 35a have a cross section, the cross-sectional area of which changes in the direction of extent. At a first end of the containment shell groove 35a, the cross-sectional area is smallest and at the other end of the containment shell groove 35a, it is at largest.

[0044] FIG. 7 shows a containment shell 3b with pitched containment shell grooves 35b, a containment shell flange 22b, screw holes 27b, and a mound 34b. The containment shell grooves 35a have a cross section, the cross-sectional area of which changes in the direction of extent. At a first end of the containment shell groove 35a, the cross-sectional area is at smallest and at the other end of the containment shell groove, it is at largest. The direction of pitch is opposite the direction of pitch of FIG. 6. The containment shell according to FIG. 6 or according to FIG. 7 can be used for both claw pole stators and stators with pronounced poles.

[0045] FIG. 8 shows a sectional view through an electric centrifugal pump 1′ according to the invention, having a motor housing 10′, a pump head 11′, a containment shell 3′, a stator 4′, and a rotor assembly 2′. The rotor assembly 2′ consists of a permanent magnet rotor 20′ and a pump impeller 16′. The pump head 11′ and the containment shell 3′ constitute the delimitation of a wet chamber 26′. The containment shell 3′ and the motor housing 10′ constitute the delimitation of a dry chamber 25′. The permanent magnet rotor 20′ comprises a permanent magnet 15′, a hollow shaft 12′, and a fixed bearing 42′. The pump impeller 16′ comprises a portion of the hollow shaft 12′, an impeller disk 41′, pump vanes 40′, an annular protrusion 7′, a spherical bearing 43′, and a cover plate 19′ (see FIG. 9).

[0046] The rotor assembly 2′ is mounted rotationally around a longitudinal motor axis 21′ and an axis component 39′, which are mounted in an axis mount sleeve 13′ as a component of the containment shell 3′ and in a mount 34′ as a component of the pump head 11′. The spherical bearing 43′ can be supported on a spherical counter bearing 44′, which is fixed in the mount 34′. The mount 34′ is integral with the pump head 11′ via spokes 33; said pump head comprising a suction nozzle 31′, a discharge nozzle 32′, and a pump head flange 23′. The containment shell 3′ comprises a containment shell bottom 17′, containment shell grooves 35′, a containment shell casing 45′, a containment shell flange 22′, and a protruding ring collar 8′ in the transition region between the containment shell casing 45′ and the containment shell flange 22′. The motor housing 10′ comprises a housing bottom 46′, a connector shaft 29′, a housing cover 47′, and a housing flange 24′. The containment shell flange 22′ is respectively connected to the pump head flange 23′ and the housing flange 24′ via an O-ring 30′. For mounting, the pump head 11′, the containment shell 3′, and the motor housing 10′ are provided with screw holes 27′ and connected to one another via screws 28′. The stator 4′, a circuit board 37′, and a supporting plate 14′ are arranged in the dry chamber 25′. The stator consists of a stator lamination 9′, a first insulating element 5′, and a second insulating element 6′, and a winding (not shown here).

[0047] FIG. 9 shows an enlarged section A of FIG. 8 with the pump head 11′, the containment shell 3′, and the pump impeller 16′. The pump impeller 16′ consists of the impeller disk 41′, the pump vanes 40′, the cover plate 19′, and the annular protrusion 7′. The containment shell 3′ comprises a containment shell flange 22′, a protruding annular collar 8′, and a recess 18′, which is adjacent to the annular collar 8′ and forms a recess for the impeller disk 41′.

[0048] FIG. 10 shows a spatial representation of the rotor assembly 2′ consisting of the permanent magnet rotor 20′ and the pump impeller 16′, with a hollow shaft 12′, the permanent magnet 15′, the impeller disk 41′, the annular protrusion 7′, the cover plate 19′, and with rotor grooves 36′. The rotor grooves 36′ extend in a first approximation parallel to the axis along an outer surface 48′ of the permanent magnet rotor 20′ but deviate in relation to straight lines parallel to the axis by a small angle. The fixed bearing 42′ can be seen inside the permanent magnet 15′.

[0049] FIG. 11 shows a front view of the rotor assembly 2′ with the permanent magnet 15′, the hollow shaft 12′, the pump impeller 16′, and the impeller disk 41′. The rotor grooves 36′ in the permanent magnet 15′ can be seen at its periphery. In this case, the rotor assembly 2′ is shown without fixed bearing.

[0050] FIG. 12 shows an enlarged section B of FIG. 11 with the permanent magnet 15′, a rotor groove 36′, and the impeller disk 41′. The rotor groove 36′ is designed in the shape of a circular segment.

[0051] FIG. 13 shows a top view of the rotor assembly 2′ with the permanent magnet rotor 20′ and the pump impeller 16′, which are connected to one another via the hollow shaft 12′. The permanent magnet 15′, the rotor grooves 36′, the impeller disk 41′, the annular protrusion 7′, and the cover plate 19′ can also be seen.

[0052] FIG. 14 shows a sectional view of the rotor assembly 2′ of FIG. 13, with the permanent magnet rotor 20′, the pump impeller 16′, the permanent magnet 15′, the hollow shaft 12′, the impeller disk 41′, the annular protrusion 7′, the pump vanes 40′, and the cover plate 19′. The impeller disk 41′, the cover plate 19′, and the pump vanes 40′ enclose conveyor channels 49′, through which the liquid to be conveyed is transported. In the hollow shaft 12′, a recessed connecting contour 50′ is provided, which allows for a positive connection to the permanent magnet 15′.

[0053] FIG. 15 shows a spatial representation of the containment shell 3′, with the containment shell casing 45′, the containment shell flange 22′, the mounting holes 27′, the protruding ring collar 8′, and the recess 18′. Containment shell grooves 35′ are present on the inner circumference of the containment shell casing 45′ and cooling ribs 38′ are present on the outer circumference of the containment shell casing 45′.

[0054] FIG. 16 shows a sectional view of the containment shell 3′, with the containment shell casing 45′, the containment shell flange 22′, the mounting eyes 27′, the protruding ring collar 8′, the recess 18′, the containment shell grooves 35′, the cooling ribs 38′, the containment shell bottom 17′, and the axis mount sleeve 13′. As can be seen in this case, the containment shell grooves 35′ are aligned parallel to the longitudinal motor axis 21′.

[0055] It is to be understood that the present invention is not limited to the illustrated embodiments described herein. Various types and styles of user interfaces may be used in accordance with the present invention without limitation. Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described.

TABLE-US-00001 LIST OF REFERENCE SYMBOLS 1 Centrifugal pump 2 Rotor assembly 3 Containment shell 4 Stator 5 First insulating element 6 Second insulating element 7 Annular protrusion 8 Protruding ring collar 9 Stator sheet package 10 Motor housing 11 Pump head 12 Hollow shaft 13 Axis mounting sleeve 14 Support plate 15 Permanent magnet 16 Pump impeller 17 Containment shell bottom 18 Recess 19 Cover plate 20 Permanent magnet rotor 21 Longitudinal motor axis 22 Containment shell flange 23 Pump head flange 24 Housing flange 25 Dry chamber 26 Wet chamber 27 Screw hole 28 Screw 29 Connector shaft 30 O-ring 31 Suction nozzle 32 Discharge nozzle 33 Spoke 34 Mount 35 Containment shell groove 36 Rotor groove 37 Circuit board 38 Cooling rib 39 Axis component 40 Pump vane 41 Impeller disk 42 Fixed bearing 43 Spherical bearing 44 Spherical counter bearing 45 Containment shell casing 46 Housing bottom 47 Housing cover 48 Outer surface 49 Conveyor channel 50 Connecting contour 51 Pole gap 52 Claw pole stator 53 Claw pole 54 Winding mounting space