ROTARY-PISTON PUMP

Abstract

The invention relates to a rotary piston pump, in particular for pumping blood, comprising a piston rotor (1) which has particularly two or three faces when seen in cross-section, which is mounted in a piston chamber (2) and eccentrically rotates, the piston rotor (1) having in its interior a plurality of magnetically interacting elements (4, 4a, 4b), in particular permanent magnets and/or coils, and being driven by the magnetic interaction of these elements (4, 4a, 4b) with at least one moving magnetic field.

Claims

1. A rotary-piston pump, particularly for supplying blood, the pump comprising: a stator housing forming a piston chamber; a piston rotor having two or three lobes as seen in cross-section and rotatable eccentrically in the piston chamber; a plurality of magnetically attractable elements inside the piston rotor and means for generating at least one moving magnetic field for driving the elements by magnetic interaction.

2. The rotary-piston pump according to claim 1, wherein the at least one moving magnetic field is produced outside the piston chamber and acts through walls of the stator housing delimiting the piston chamber.

3. The rotary-piston pump according to claim 1, wherein the magnetically attractable elements in the piston rotor are positioned in the vicinity of ends of the lobes and the means for generating includes a plurality of coils alternatingly energizable in order to produce the moving magnetic field and positioned angularly in the stator housing around and outside of the piston chamber, with the magnetically attractable elements and the coils being situated radially opposite one another.

4. The rotary-piston pump according to claim 3, wherein the magnetically attractable elements and the energizable coils are arranged in at least two respective groups spaced from each other axially, with each group of magnetically attractable elements being associated with a respective group of energizable coils for magnetic interaction and in particular, with the respective groups being positioned in the vicinity of axial end faces of the piston rotor and piston chamber.

5. The rotary-piston pump according to claim 1, wherein the magnetically attractable elements in the piston rotor are positioned in the vicinity of at least one axial end face and a plurality of coils alternatingly energizable in order to produce the moving magnetic field is positioned spaced axially from the magnetically attractable elements of the piston rotor behind an axial end wall of the piston chamber with the coils positioned in accordance with the cross-sectional shape of the surface or in accordance with the trajectory of the magnetically attractable elements of the piston rotor or behind an axial end wall of the piston chamber, a plurality of permanent magnets is positioned spaced axially from the magnetically attractable elements of the piston rotor on a rotatable rotor an eccentrically rotatable rotor that is driven or at least can be driven by a motor.

6. The rotary-piston pump according to claim 1, wherein the piston rotor is magnetically supported in an eccentrically rotatable fashion on at least one of its axial end faces.

7. The rotary-piston pump according to claim 6, wherein the support is a first magnetic or magnetizable ring fastened centrally to an axial piston chamber wall, and a second magnetic or magnetizable ring positioned eccentrically at the axial end face in the piston rotor and, with the rotation of the piston rotor, rolling with its inner ring surface against the outer ring surface of the first ring with a magnetically attracting interaction directly or indirectly via a magnetizable material.

8. The rotary-piston pump according to claim 1, wherein the magnetically attractable elements are positioned in an eccentric supported in a centrally rotatable fashion in the piston rotor.

9. The rotary-piston pump according to claim 8, wherein the at least one moving magnetic field is produced inside the piston rotor and acts through at least one wall of the piston rotor surrounding the eccentric.

10. The rotary-piston pump according to claim 8, wherein the eccentric is positioned in the piston rotor centrally relative to the axial length of the piston rotor and on both sides of the eccentric behind an axial wall of the piston rotor, the piston rotor has an inner recess in which a rotor that can be centrally rotated by a motor is situated and that has a plurality of permanent magnets spaced axially from the magnetically attractable elements of the piston rotor.

11. The rotary-piston pump according to claim 7, wherein the rotation shaft of the at least one rotatable rotor extends through the first magnetic or at least magnetizable ring of a magnetic support of the piston rotor which ring is fastened centrally to an axial piston chamber wall.

12. The rotary-piston pump according to claim 1, wherein a plurality of permanent magnets for forming the magnetically attractable elements of the piston rotor or a plurality of permanent magnets of the rotatable rotor is composed of a permanent magnet ring that is multiply magnetized in alternating fashion angularly.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0055] The possible embodiments of the rotary-piston pump according to the invention will be discussed below with reference to the figures. Therein:

[0056] FIG. 1A is a section taken along line 1A-1A of FIG. 1B of a pump according to the invention;

[0057] FIGS. 1B and 1C are sections taken along respective lines 1B-1B and 1C-1C of FIG. 1A;

[0058] FIG. 2A is a perspective sectional view taken along line 2A-2A of FIG. 2D;

[0059] FIGS. 2B and 2C are sections taken along respective lines 2B-2B and 2C-2C of FIG. 2D; and

[0060] FIG. 2D is an axial end view of the pump of FIGS. 2A-2C;

[0061] FIG. 3A is a section taken along line 3A-3A of FIG. 3B;

[0062] FIGS. 3B and 3C are sections taken along respective lines 3B-3B and 3C-3C of FIG. 3A;

[0063] FIG. 4A is a section taken along line 4A-4A of FIG. 4C;

[0064] FIG. 4B is a section taken along line 4B-4B of FIG. 4D; and

[0065] FIGS. 4C and 4D are sections taken along respective lines 4C-4C and 4D-4D of FIG. 4A.

SPECIFIC DESCRIPTION OF THE INVENTION

[0066] In a plurality of views, FIGS. 1A-C show a first embodiment of a rotary-piston pump according to the invention. The piston pump has a three-lobe piston rotor 1 that is rotated eccentrically about a central axis A of a piston chamber 2.

[0067] The piston rotor is formed as a hypotrochoid. The piston chamber 2 here, in cross-section perpendicular to its central axis A, has the shape of the associated envelope. The shape of the inner surface 3 of the piston chamber 2 thus also corresponds to this envelope, particularly taking into account an offset from the mathematically calculated envelope in order to form a gap between the piston rotor and the piston chamber.

[0068] In this case, the piston rotor 1, which is referred to as three-lobe, is essentially a triangular shape with rounded corners and slightly bulging faces. The cross-sectional form perpendicular to the central axis A of the piston chamber preferably corresponds to the above-mentioned hypotrochoid.

[0069] The embodiment in FIGS. 1A-C has no additional support of the piston rotor 1, i.e. it is basically able to move freely inside the piston chamber 2 with respect to rotation.

[0070] The eccentric rotary motion or revolving motion of the piston rotor here is the result of a magnetic coupling between the piston rotor 1 and at least one magnetic field produced outside the piston chamber 2. To this end, according to the invention, a plurality of electrically magnetically attractable elements 4, namely permanent magnets 4 in this case, is embedded in the piston rotor 1 each at a radially outer end of respective one of the three lobes of the three-lobe piston rotor. In other words, these elements are essentially positioned close to the rounded corners of the triangular shape.

[0071] A plurality of coils spaced angularly around the central axis A of the piston chamber 2 can be energized in alternating fashion so that the alternating energization of the individual coils 5 creates one or a plurality of magnetic field that orbit around the piston chamber.

[0072] Preferably in this case, an appropriate energization of the individual coils 5 causes the coils 5 to magnetically interact with the magnetically attractable elements 4 of the piston rotorin other words in this case, three coils 5 or coil groups each enter into a magnetic interaction with a respective one of the three elements 4and in particular through an attracting magnetic interaction or alternatively through a repulsing magnetic interaction, an eccentric rotation of the piston rotor 1 is produced.

[0073] The sectional views from the left side in the direction of the central axis A of the piston chamber 2 also show that inside the piston rotor 1, two groups of magnetically attractable elements 4 are provided, namely elements 4a of the first group and elements 4b of the second group, with the elements of these two different groups being spaced apart axially of the central axis A of the piston chamber 2, preferably with these elements being provided positioned in the respective axial end faces of the piston rotor 1.

[0074] In radial opposition, correspondingly energizable coils 5a and 5b, respectively, are also positioned at the axial end faces of the piston chamber, spaced angularly around the piston chamber, i.e. following the envelope. Here as well, this therefore yields two groups of coils, with each group of magnetically attractable elements 4 of the piston rotor being associated with exactly one group of coils 5, thus in this case, there is an association between the elements 4a and the coils 5a and between the elements 4b and the coils 5b.

[0075] The positioning of the two groups at the axial end faces makes it possible to ensure that the piston rotor is subjected to no axial tilting or at least no significant axial tilting during its eccentric rotation.

[0076] FIGS. 1A-C also show that the rotary-piston pump described here can perform two separate functions, namely on the one hand, a pump function between an inlet 6a and outlet 6b and on the other hand, a pump function between the inlet 7a and the outlet 7b. Such a division is particularly advantageous in the use as a heart pump since it is thus possible to implement separate pulmonary and systemic circulations. This division, however, is not compulsory; it is also possible to set up a rotary-piston pump for supplying any media, for example also blood, with only one pump inlet and one pump outlet. The corresponding implementations essentially depend on the specific cross-sectional shapes of the piston rotor and piston chamber. In an embodiment of the piston rotor with only two lobes, a rotary-piston pump according to the invention will therefore have only one inlet and one outlet. For example, it is possible to use a pump of this kind to support only a systemic circulation or alternatively, two such pumps are used.

[0077] FIG. 2 shows an alternative embodiment of the rotary-piston pump according to the invention in which magnetically attractable elements 4a and 4b are each once again positioned in the above-mentioned group arrangement at the axial end faces of the piston rotor 1; in this case, each groupas in the preceding embodimentpreferably has a number of magnetically attractable elements that corresponds to the number of lobes of the piston rotor. In this case, the magnetically attractable elements 4a and 4b can, for example, be positioned in recesses in the axial end faces of the piston rotor.

[0078] One possible variant, which is not however shown here, can also have axial permanent magnets in the flanks of the piston rotor, in particular three magnets at the ends of the lobes and three magnets interleaved with these magnets, preferably at the narrowest point between the outer wall of the piston rotor and the annular magnet of the piston rotor.

[0079] Outside the piston chamber, which is sealed off from the outside by axial end walls 2a, there is a plurality of coils 5, in this case once again in group arrangements, i.e. coils 5a in a first group and coils 5b in a second group, with the two groups on the two axially opposite end walls of the piston chamber. This therefore produces an axial spacing between the coils and the magnetically attractable elements of the piston rotor in comparison to the radial spacing of the embodiment according to FIGS. 1A-C.

[0080] In this case, the individual coils 5a and 5b are positioned in such a way that this positioning essentially follows the envelope of the trochoidal piston rotor and overlaps the trajectory of the respective magnetically attractable elements 4a and 4b. This means that an optimal axial opposition is produced between each magnetically attractable element 4a and 4b of the piston rotor and the respective coils at each position of the eccentric rotary motion of the piston rotor.

[0081] The embodiment in FIGS. 2A-D also show that, at both axial end faces of the rotary-piston pump according to the invention, the piston rotor 1 also has a support that forcibly guides the eccentric motion of the piston rotor 1. In this case, this support comprises a first permanent magnet ring 8a centered on the central axis A of the piston chamber and a second ring 8b eccentric to the axis A, particularly so that during a rotation of the piston rotor 1, the inner ring surface of the outer ring 8b rolls directly or indirectly against the surface of the inner ring 8a with a magnetically attracting action.

[0082] In this case, the inner ring 8a positioned centrally with its ring center on the axis A, is fastened to a centrally positioned journal on the axial piston chamber wall 2a and projects into an inner recess 1b on the respective axial end face of the piston rotor 1. The outer eccentrically positioned ring 8b, whose center thus lies radially next to the axis A, is fastened in the recess 1b of the piston rotor 1.

[0083] FIGS. 3A-C show another embodiment in which, with reference to FIG. 3A, shows a magnetic support with an inner first magnetic or at least magnetizable ring 8a and an outer second magnetic or at least magnetizable ring 8b and the magnetic drive is at the axially opposite end, i.e. in this case the bottom end, for which purpose the piston rotor 1 once again has magnetically attractable elements 4 such as permanent magnets on its axial end face.

[0084] Positioned spaced axially from and outside the piston chamber 2, there is a rotor that supports permanent magnets 9 whose positioning relative to one another corresponds to that of the magnetically attractable elements 4 of the piston rotor 1 so that each magnetically attractable element 4 of the piston rotor is associated with a permanent magnet of the rotor.

[0085] The rotor 10 in this case can be rotated eccentrically relative to the central axis A of the piston chamber so that the individual elements 9, in particular the permanent magnets, thus have an eccentrically rotated trajectory and thus cause the piston rotor with its elements 4 to move along with them on the same path. Therefore in this case as well, the piston rotor 1 also executes an eccentric rotation, which is also forcibly guided by the magnetic support with the rings 8a and 8b that have the same eccentricity in the support as the elements 9 of the rotor 10.

[0086] In this case, the rotor 10 can be guided on an eccentric trajectory by gears 11. The gears, for example, can form a ring gear train or planetary gear train. The rotor can be driven by a conventional electric motor; it is clear from the drawing that all of the components of the rotor are outside the piston chamber 2 and the piston rotor 1 is driven by magnetic interaction through the piston chamber wall 2a at the axial end face.

[0087] In the embodiment according to FIGS. 3A-C, the magnetically attractable elements 4 of the piston rotor 1 are stationary relative to the piston rotor.

[0088] By contrast with this, FIGS. 4A-D show an arrangement in which the magnetically attractable elements 4 in the form of circularly positioned permanent magnets or alternatively in the form of a permanent magnet ring in the piston rotor are positioned centrally around the central axis A, these elements being accommodated by a circular eccentric 12 rotationally supported in the piston rotor 1 by a support 13 that surrounds the eccentric 12. The rotation of the piston rotor 1 on an eccentric trajectory in this case occurs due to the fact that as a result of magnetic interaction between a rotor that is rotated centrally about the piston chamber central axis A, with permanent magnets, the permanent magnets 4 of the eccentric 12 are rotated centrally, which causes the eccentric 12 to rotate about the central axis A of the piston chamber 2, and, because of the inherent eccentricity of the piston rotor 1, forces the latter to follow an eccentric trajectory in the piston chamber.

[0089] The embodiment here is also designed in such a way that the eccentric 12 is positioned centrally in the piston rotor 1 relative to the central axis A and the axial length of the piston rotor 1, with inner recesses 14 being provided on both sides of the middle inside the piston rotor, in which recesses rotors 15 are positioned that rotate about the central axis A and have magnetically attractable elements 9, in particular permanent magnets, positioned around the central axis A. In this case, the shaft 16 of the rotors 15 is inserted through an inner ring 8a of a magnetic eccentric support, as has already been described in relation to the above-mentioned figures.

[0090] The depiction of the axial end face section in FIGS. 4A-D here shows that the inner ring surface of the outer magnetic ring 8b rolls along the outer ring surface of the inner centrally supported magnetic ring 8a so that, the eccentric motion of the piston rotor 1 is furthermore forcibly guided by this rolling motion. An annular intermediate element can be positioned between the rings or else at least one ring can support a coating, which can apply generally to all of the possible embodiments with such a magnetic ring support and not just to the embodiment shown here.

[0091] It should also be noted that in order to embody the magnetic support in all of the above-described figures, it is only necessary for one of the two above-mentioned rings to be magnetic whereas the other ring only has to be magnetizable. Alternatively, it is naturally also possible for both to be magnetic. The magnetizations of the rings here can be radial, axial, or in some other way so that an attracting interaction is produced between these rings as they roll against each other.