Pumping device, single-use device, and method for operating pumping device

Abstract

To provide a pumping device for conveying a fluid, the pumping device including a single-use device and a reusable device, and a method for operating the same.SOLUTION: A single-use device 2 is to be inserted into a reusable device 3 and includes two pump units 21, 22 in series, one behind the other. Each pump unit includes a rotor designed as a rotor for a bearingless motor, and can be magnetically levitated and driven without contact. The reusable device 3 includes a stator 31, 32 for each rotor which forms an electromagnetic rotary drive for rotating the rotor. Each stator is a bearing and drive stator with which the rotor can be magnetically driven without contact and magnetically levitated without contact with respect to the stator. An independent control device is provided for each stator, and can independently activate the stator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pumping device for transporting fluids, a disposable device for such a pumping device, and a method for operating a pumping device. [Background technology]

[0002] In biotechnological or medical technical applications, pumps must often be able to transport very sensitive substances such as blood, cell cultures or proteins, and it is therefore of great importance that these substances are damaged as little as possible by the pump. For this purpose, peristaltic pumps are known on the one hand, and centrifugal pumps on the other hand, in which a rotating rotor with blades (impeller) acts on the fluid to be transported.

[0003] Centrifugal pumps with electromagnetic rotary drives designed and operated according to the bearingless motor principle are known. The term "bearingless motor" refers to an electromagnetic rotary drive in which the rotor is fully magnetically levitated relative to the stator and does not have a separate magnetic bearing. For this reason, the stator is designed as both an electrically driven and a magnetically levitated support and drive stator. A magnetically rotating magnetic field can be generated by the stator's electrical windings. The magnetically rotating magnetic field exerts a torque on the rotor, which affects its rotation, and a shear force on the rotor, which can be set as desired, thereby actively controlling or adjusting the rotor's radial position. Thus, three degrees of freedom of the rotor, namely, its rotation and radial position (two degrees of freedom), can be actively adjusted. With respect to the three further degrees of freedom, namely, the rotor's axial position and its tilt relative to a radial plane perpendicular to the desired rotation axis (two degrees of freedom), the rotor is passively levitated or stabilized by magnetic reluctance forces; i.e., the rotor cannot be actively controlled. Complete magnetic levitation of the rotor characterizes the absence of separate magnetic bearings, hence the name bearingless motor.

[0004] Bearingless motors are already quite well known to those skilled in the art and are used in many different applications. Some basic descriptions can be found, for example, in European Patents A-0 860 046 and A-0 819 330.

[0005] Centrifugal pumps designed according to the bearingless motor principle have proven themselves in many applications.

[0006] Due to the absence of mechanical bearings, centrifugal pumps designed according to the bearingless motor principle are particularly suitable for applications in which the very sensitive substances mentioned at the beginning are transported, such as blood pumps or pumps with very high demands on purity, for example in the pharmaceutical or biotechnology industry, or also for applications in which abrasive or corrosive substances that would destroy mechanical bearings very quickly, such as pumps for slurry or acidic fluids in the semiconductor industry.

[0007] Examples of such applications include extracorporeal membrane oxygenation (ECMO), in which blood is continuously pumped through a membrane oxygenator that replaces gas exchange within the lungs, removing carbon dioxide from the blood and enriching it with oxygen. Additionally, there are machines that take over the function of the lungs during surgery, such as heart-lung machines (CPB). For example, in biotechnology, pumps are needed to circulate nutrient solutions through bioreactors or to move fluids through filter units that extract substrates to be produced.

[0008] In these applications, and in particular in medical technology and biotechnology, it is of course necessary to implement redundancy, since in the event of a pumping device failure it is of course necessary to ensure that neither the patient nor the substance to be produced is put at risk.It is therefore common practice to have a second, usually identical, pumping device ready to replace the defective one and take over its function in the event of a pumping device failure.

[0009] In all such applications, centrifugal pumps designed according to the bearingless motor principle have proven successful, especially since no mechanical bearings are provided here, which could have a negative impact on the purity of the process.

[0010] A further advantage of the bearingless motor principle is the design of the rotor as a single unit, which is both the rotor of the electromagnetic drive and the rotor of the centrifugal pump. In addition to contactless magnetic levitation, the advantage here is a very compact and space-saving design.

[0011] Additionally, the bearingless motor principle also allows centrifugal pumps to be designed in such a way that the rotor or the pump housing in which the rotor is located can be very easily separated from the stator. This is a significant advantage, since, for example, the pump housing in which the rotor is located can be designed as a disposable part for single use. Today, such disposable applications often replace processes in which, due to very high purity requirements, all components that come into contact with the fluid to be processed had to be meticulously cleaned and sterilized, for example, using steam sterilization. In a single-use design, the components that come into contact with the fluid to be processed are used exactly once and then replaced with new, i.e., unused, disposable parts for the next use.

[0012] A problem that arises when using centrifugal pumps to transport sensitive substances such as blood or other biological fluids is the interaction between the rotor blades and the fluid to be transported. In this regard, there are two aspects that specifically lead to damage to cells present in the fluid, such as red blood cells: the shear force acting on the cells or other particles, and the residence time of the shear force, i.e., the time the particles are exposed to this shear force. However, it is known that the magnitude of the shear force is a more important factor in terms of damage to the transported fluid. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] European Patent A-0 860 046 [Patent Document 2] European Patent A-0 819 330 Summary of the Invention [Problem to be solved by the invention]

[0014] Starting from this state of the art, it is therefore the object of the present invention to propose a pump device which, on the one hand, makes it possible to transport highly sensitive fluids, such as those containing cells, with minimal damage to the fluid, and which, on the other hand, is redundant.Furthermore, disposable components for such a pump device and a method for operating such a pump device are proposed. [Means for solving the problem]

[0015] The subject matter of the invention, which meets these objectives, is characterized by the features of the independent claims of each category.

[0016] Therefore, according to the present invention, a pump device for transporting a fluid is proposed, comprising a disposable device designed for single use only, and a reusable device designed for multiple use, wherein the disposable device is designed to be inserted into the reusable device and comprises two pump units arranged in series one behind the other, each pump unit comprising a rotor for transporting a fluid, each rotor designed as the rotor of a bearingless motor and capable of being magnetically levitated without contact and driven to rotate around an axial center without contact, and the reusable device is designed to have the disposable device inserted therein and comprises a stator for each rotor which, together with the rotor, forms an electromagnetic rotary drive for rotating the rotor around an axial center, each stator designed as a support and drive stator by means of which the rotor can be magnetically driven without contact and can be magnetically levitated relative to the stator without contact, and each stator is provided with a separate control device designed to activate each stator separately.

[0017] Therefore, a reusable device designed for multiple uses is designed so that a disposable device can be inserted into the reusable device, allowing for very easy assembly and separation of the reusable and disposable devices. Because the pump device according to the present invention includes two pump units arranged in series, for a given pressure to be generated by the pump device, the two rotors can operate at a lower rotational speed than if the same pressure were to be generated using only one pump unit, i.e., only one rotor. It is known that damage to cells, such as red blood cells, contained in biological fluids transported by centrifugal pumps increases disproportionately with the rotational speed of the centrifugal pump. The rotational speed at which the centrifugal pump operates is a crucial factor in the magnitude of the shear force experienced by biological cells in the fluid. Furthermore, the magnitude of this shear force is an essential factor in causing cell damage or destruction.

[0018] It is known that in centrifugal pumps, the pressure generated, or more precisely the pressure difference between the pressure at the pump inlet and the pressure at the pump outlet, is at least very nearly proportional to the square of the rotational speed. However, this means that if the pressure difference is generated by two identical pump units connected in series, the rotational speed of each pump unit will be proportional to the square root of two.

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[0019] In addition, since a separate control device is provided for each stator, allowing each stator to be activated independently, the pump device according to the invention allows for hot redundancy so that a replacement pump device does not have to be kept available. In normal, i.e. fault-free operation, two pump units connected in series together generate a predetermined pressure difference. Now, if one of the two pump units fails, the rotational speed of the other pump unit will be reduced by the square root of 2.

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[0020] According to a preferred embodiment, the disposable device has two cup-shaped protuberances in each of which a rotor is provided, and the reusable device has two recesses, each of which is designed to receive one of the cup-shaped protuberances. This embodiment allows for particularly easy assembly and separation of the disposable and reusable devices.

[0021] In a preferred embodiment, the reusable device is designed such that, in the operating state, the rotors of the disposable device each rotate about an axis of rotation that forms an angle with the vertical that is less than 90° and different from zero. In this embodiment, in the operating state, the two pump units are arranged one behind the other in a plane that is inclined with respect to the horizontal and with respect to the vertical. This embodiment is particularly advantageous for priming the pump units, since it is more effective in preventing gas bubbles from adhering, for example, in the flow connection between the two pump units, as in a siphon.

[0022] According to a preferred embodiment, each pump unit is configured as a radial pump unit, with the first pump unit having a first fluid inlet and a first fluid outlet, and the second pump unit having a second fluid inlet and a second fluid outlet, each inlet designed for fluid to flow axially into the respective rotor, and each outlet designed for fluid to exit the respective pump unit in a discharge direction aligned perpendicular to the axial direction.

[0023] In a first embodiment, the disposable pump device is designed so that the fluid changes direction by at least 90°, preferably 90°, between the first outlet and the second inlet. When the disposable device is aligned so that the rotation axis of the pump unit is aligned vertically (toward gravity), the two pump units are axially offset. The fluid exits the first pump unit in a discharge direction extending perpendicular to the axial direction, is then changed direction by 90°, and then flows vertically through the second inlet of the second pump unit.

[0024] In a second embodiment, the disposable pump device is designed to allow fluid to change direction by a total of 270° between the first outlet and the second inlet. When the disposable device is aligned so that the rotation axis of the pump units is aligned vertically (in the direction of gravity), the two pump units are positioned at the same vertical height, i.e., next to each other. The fluid exits the first pump unit in a discharge direction extending vertically, then first changes direction vertically upward by 90°, then again vertically (horizontally), then changes direction vertically downward by 90°, and finally flows vertically through the second inlet of the second pump unit.

[0025] Providing a separate power supply for each stator is an advantageous measure, so that if one of the power supplies fails, one of the stators can still be powered. Each stator, as well as the control device assigned to it and, if necessary, other components assigned to this stator, are therefore completely independent of the power supply, i.e. they can be activated as well as powered completely independently of the state of the other stator or stators.

[0026] An advantageous option is to provide a higher-level control unit which is signal-connected to all control devices of the stator.

[0027] A further advantageous option is to provide an emergency energy storage device that can supply energy to each stator in the event that the main energy source supplying the stators is no longer able to provide energy to one or all of the pump units.

[0028] The main energy source can be designed, for example, as a power supply unit that receives power from an external power supply system. The emergency energy storage device can be designed, for example, as an accumulator or battery, which still provides energy when the power supply unit is not connected to the external power supply system or when the power supply unit fails. This accumulator or battery is very advantageous, for example, when a patient is connected to a pump device and has to be transported from one place to another.

[0029] Each power supply preferably comprises both a main energy source designed as a power supply unit connectable to an external power supply system and an accumulator or battery as an emergency energy storage device.

[0030] It is further advantageous for the disposable and / or reusable devices to incorporate an identification element, by means of which the disposable and reusable devices can exchange information with each other. In particular, each identification element can also be designed as an RFID (radio-frequency identification) or as a barcode, in particular a two-dimensional or three-dimensional barcode.

[0031] Furthermore, a disposable device designed for a pump device designed according to the present invention is proposed in the present invention for single use only.

[0032] The present invention also proposes a method for operating a pump device designed according to the present invention, wherein desired values ​​of operating parameters of the pump device are predetermined in each control device, actual values ​​of these operating parameters are determined using sensors, and the actual values ​​are transmitted to each control device.

[0033] Preferably, the control devices exchange signals with each other so that each control device can determine that the other's pump unit is functioning.

[0034] A preferred operating parameter is the flow rate through the pumping device or the pressure differential generated by the pumping device.

[0035] It is an advantageous option that the flow rate through the pump device is determined from the rotational speed and torque at which the rotor is driven.

[0036] Further advantageous measures and embodiments of the invention emerge from the dependent claims.

[0037] In the following, the invention will be explained in more detail on the basis of examples, both from the point of view of device and process engineering, and on the basis of drawings, in which: In the schematic drawing (partly in cross section) are shown: [Brief explanation of the drawings]

[0038] [Figure 1] 3 is a schematic cross-sectional view of a first embodiment of a pump device according to the present invention, taken along the section line I-I in FIG. 2. [Figure 2] 2 is a schematic cross-sectional view of the first embodiment taken along the cross-sectional line II-II in FIG. [Figure 3] 5 is a schematic cross-sectional view of a first variant of the disposable device taken along the section line III-III in FIG. 4. FIG. [Figure 4] 4 is a schematic cross-sectional view of a first variant of the disposable device taken along the cross-sectional line IV-IV in FIG. 3. FIG. [Figure 5] 7 is a schematic cross-sectional view of a second embodiment of a pump device according to the present invention, taken along the cross-sectional line V-V in FIG. 6. [Figure 6] 6 is a schematic cross-sectional view of the second embodiment taken along the cross-sectional line VI-VI in FIG. 5. FIG. [Figure 7] 7 is a schematic cross-sectional view of a second variant of the disposable device taken along the cross-sectional line VII-VII of FIG. 8. FIG. [Figure 8] 8 is a schematic cross-sectional view of a second variant of the disposable device taken along the section line VIII-VIII of FIG. 7. [Figure 9] 6 is a schematic cross-sectional view of a third embodiment of a pump device according to the invention, in a cross-section similar to that of FIG. 5. [Figure 10] 12 is a schematic cross-sectional view of a fourth embodiment of a pump device according to the present invention, taken along the cross-sectional line X-X in FIG. 11. [Figure 11] 11 is a schematic cross-sectional view of a fourth embodiment of a pump device according to the present invention, taken along the cross-sectional line XI-XI of FIG. 10. [Figure 12] 12 is a schematic cross-sectional view of a third variant of the disposable device taken along the cross-sectional line XII-XII in FIG. 13. FIG. [Figure 13] 13 is a schematic cross-sectional view of a third variant of the disposable device taken along the cross-sectional line XIII-XIII in FIG. 12. FIG. [Figure 14] 14 is a schematic cross-sectional view of a third variant of the disposable device taken along the cross-sectional line XIV-XIV in FIG. 12. FIG. [Figure 15] 1 is a symbolic diagram of an embodiment of a pump device according to the invention for explaining an embodiment of a method according to the invention for operating the pump device according to the invention; [Figure 16] 2 is a flow chart of an embodiment of a method according to the present invention; [Figure 17] 16 is a view similar to FIG. 15 of a variant of the embodiment of the method according to the invention; [Figure 18] 16 is a view similar to FIG. 15 of a variant of the embodiment of the method according to the invention; [Figure 19] 16 is a view similar to FIG. 15 of a variant of the embodiment of the method according to the invention; [Figure 20] 16 is a view similar to FIG. 15 of a variant of the embodiment of the method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0039] In the following description of the present invention based on embodiments, example embodiments, and variants, the same or functionally equivalent parts are designated by the same reference numerals throughout. It should be understood that the description of one example embodiment, a specific embodiment, or a specific variant also applies in the same way or similarly to other embodiments, example embodiments, and variants. This means that only the differences from the above-mentioned embodiments, example embodiments, or variants will be discussed in more detail.

[0040] Figure 1 shows in a schematic cross-section a first embodiment of a pump device according to the invention, which pump device is generally designated by the reference number 1. For a better understanding, Figure 2 also shows a schematic cross-section of the first embodiment of a pump device 1 according to the invention, the cross-section being made along the section line II-II in Figure 2. In Figure 2, the section line I-I is drawn for the cross-section shown in Figure 1.

[0041] To ensure the purity or sterility of those components that come into contact with the fluid to be transported, e.g., blood or another biological fluid, the pump device 1 comprises a disposable device generally designated by the reference numeral 2, designed for single use, and a reusable device generally designated by the reference numeral 3, designed for permanent use, i.e., multiple uses. The disposable device 2 comprises those components that come into contact with the fluid to be transported during operation of the pump device 1.

[0042] The terms "disposable device" and other phrases containing "disposable" components, such as disposable part and disposable component, refer to such components or parts that are designed for single use, i.e., for use only once as intended and then discarded. A new use then requires the insertion of a new, previously unused disposable part. Therefore, when constructing or designing a disposable device 2, it is essential that the disposable device 2 be manufactured as simply and economically as possible, resulting in low costs. Another essential aspect is that the disposable device 2 can be combined with and separated from a reusable device 3 as easily as possible. Therefore, the disposable device 2 should be very easily replaceable without requiring advanced assembly work. It is particularly preferable that the disposable device 2 can be combined with and separated from a reusable device 3 without the use of tools.

[0043] For this reason, the disposable device 2 is designed to be inserted into the reusable device 3, and the reusable device 3 is designed to receive the disposable device 2, i.e., so that the disposable device 2 can be inserted into the reusable device 3.

[0044] The disposable device 2 is designed according to a first variant, which is shown in two schematic cross-sectional views in Figures 3 and 4. Figure 3 shows the first variant of the disposable device 2 in a cross-section along the section line III-III in Figure 4, and Figure 4 shows the first variant of the disposable device in a cross-section along the section line IV-IV in Figure 3.

[0045] The disposable device 2 comprises two pump units, namely a first pump unit 21 and a second pump unit 22. The first pump unit 21 has a first inlet 211 and a first outlet 212 for the fluid to be transported. The second pump unit 22 has a second inlet 221 and a second outlet 222 for the fluid to be transported. The two pump units 21, 22 are arranged in series, i.e., one behind the other. That is, the first outlet 212 is flow-connected to the second inlet 221 by a connecting channel 23. Thus, in operation, fluid flows into the first pump unit 21 through the first inlet 211, flows through the first pump unit 21, and exits the first pump unit 21 through the first outlet 212. From there, the fluid travels through the connecting channel 23 to the second inlet 221, flows through the second pump unit 22 and exits the second pump unit 22 through the second outlet 222. This is represented by the two unnumbered arrows in Figure 1.

[0046] Each pump unit 21, 22 comprises a pump housing 213 or 223 (FIG. 3), respectively, in which a rotor 214 or 224, respectively, is provided for transporting the fluid and forms the respective impeller of the pump unit 21. The respective rotors 214, 224 are jointly designed as rotors 214, 224 of an electromagnetic rotary drive, each constructed according to the principle of a bearingless motor, as will be explained further below. To this end, each rotor 214, 224 comprises a magnetically active core 215 or 225, respectively, which can be made, for example, as a permanent magnetic ring or as a ring of soft magnetic material, such as iron. Typically, this magnetically active core 215 or 225 is completely coated or encapsulated, with the coating preferably made of plastic. An impeller 216 or 226 is then provided on the respective coating and acts on the fluid to be transported using a plurality of blades.

[0047] Each pump unit 21, 22 is preferably designed as a radial centrifugal pump in which the respective rotor 214, 215 rotates about a rotation axis A1 or A2, and the fluid flows into the respective rotor 214, 224 in the direction of the respective rotation axis A1 or A2, which redirects the fluid in a discharge direction D (FIG. 4) perpendicular to the respective rotation axis A1 or A2.

[0048] The two pump units 21, 22 are preferably, but not necessarily, designed to be at least hydraulically identical. It is particularly preferred that the rotation axes A1 and A2 are parallel to one another. This common direction in which the two parallel rotation axes A1, A2 extend is referred to below as the axial direction A. The direction perpendicular to the axial direction A is referred to as the radial direction.

[0049] Furthermore, it is preferred that the two pump units 21, 22 are firmly connected to each other by a connecting channel 23, whereby the two pump units 21, 22 together with the connecting channel 23 form a structural unit, which as a whole can be inserted into the reusable device 3.

[0050] The longitudinal direction of the connecting channel 23 determines the discharge direction D (Fig. 4) in which the fluid leaves the first pump unit 21. The connecting channel 23 is aligned so that, on the one hand, the discharge direction D is perpendicular to the axial direction A and, on the other hand, forms an angle different from 0° and different from 90° with an imaginary shortest connecting line M between the two rotation axes A1 and A2. In the view in Fig. 4, the connecting line M lies on the cross-sectional line III-III.

[0051] 1 and 3, in a first variant of the disposable device 2, the connecting channel 23 is designed so that the fluid changes direction by 90° relative to the axial direction A between the first outlet 212 and the second inlet 221. The connecting channel 23 initially extends downstream of the first outlet 212 perpendicular to the axial direction A, so that the discharge direction D is perpendicular to the axial direction A. The connecting channel 23 then bends downward by 90° so that the fluid flows in the axial direction A through the second inlet 221. Here, "down" refers to the diagrams in FIGS. 1 and 3. This embodiment results in that, in the usage position shown in FIG. 1, the rotation axes A1 and A2 of the pump units 21 and 22, respectively, are aligned vertically (in the direction of gravity), and the two pump units 21 and 22 are offset from the vertical direction.

[0052] Each pump unit 21, 22 has a pot-shaped or cup-shaped protuberance 217 or 227, where the protuberance is formed by the respective pump housing 213 or 223. Each rotor 214, 224 is disposed within the mating pump housing 213 or 223 such that at least the magnetically effective core 215 or 225 of the respective rotor 214, 224 is disposed within the respective cup-shaped protuberance 217 or 227.

[0053] The reusable device 3 (FIG. 1) comprises a stator housing 35 in which two stators, a first stator 31 and a second stator 32, are provided to interact with one of the rotors 214 or 224. The reusable device 3 further comprises two pot- or cup-shaped recesses 33 or 34 provided in the stator housing 35 and dimensioned and arranged so that each of the cup-shaped recesses 33, 34 can receive and surround one of the respective cup-shaped protuberances 217, 227 of the disposable device 2. The dimensions of each recess 33, 34 and each protuberance 217, 227 are matched to one another so that, in the assembled state, each recess 33, 34 closely surrounds one of the protuberances 217, 227 and the outer surface of each recess 33, 34 abuts the outer surface of the respective protuberance 217, 227.

[0054] Each of the two stators 31, 32 is arranged around one of the recesses 33 or 34, surrounding the respective recess 33, 34 as closely as possible. Each stator 31, 32 is arranged such that, in the assembled state of the pump device 1, each of the magnetically active cores 215, 225 is surrounded by the respective one of the stators 31, 32 or by the stator poles of the stator 31 or 32, thereby providing the best possible magnetic interaction between the respective stator 31, 32 and the respective magnetically active core 215, 225.

[0055] The embodiment with the ridges 217, 227 of the disposable device 2 and the recesses 33, 34 of the reusable device 3 allows a particularly easy connection or separation of the disposable device 2 and the reusable device 3. The two ridges 217, 227 with the rotors 214, 224 arranged therein are inserted into the two recesses 33, 34 in a simple manner and the pump device 1 is ready for operation. In the same simple manner, the two ridges 217, 227 can be pulled out of the recesses 33, 34, thereby separating the disposable device 2 from the reusable device 3. Of course, safety elements, such as snap connections, can be provided to prevent unintentional separation of the disposable device 2 and the reusable device 3.

[0056] As already mentioned, the two rotors 214, 224 and the two stators 31, 32 are designed in such a way that the first stator 31 and the first rotor 214, and the second stator 32 and the second rotor 224 form an electromagnetic rotary drive designed as a bearingless motor.

[0057] For this reason, each stator 31, 32 is designed as a support and drive stator that can magnetically drive the respective rotor 214, 224 to rotate around the respective rotation axis A1, A2 without contact and can magnetically levitate the rotor 214, 224 relative to the stator 31, 32 without contact.

[0058] Since the two rotation axes A1 and A2 are parallel, the axial direction A will be used as the reference in the following.

[0059] The magnetically active core 215 or 225 of the rotor 214 or 224, which may be designed in the form of a circular disk or a cylinder, i.e., annular, refers to that area of ​​the rotor 214, 224 that interacts with the respective stator 31, 32 to generate torque and generate magnetic support. Depending on the design, the magnetically active core 215, 225 may include one or more permanent magnets. Alternatively, it is also possible to design the magnetically active core 215, 225 without permanent magnets, for example as a reluctance rotor. In this case, the magnetically active core 215, 225 consists at least partially of a ferromagnetic material, for example iron.

[0060] The respective rotary drive with the first rotor 214 and the first stator 31 or with the second rotor 224 and the second stator 32 is designed, for example, as a so-called temple motor.

[0061] A feature of the embodiment as a temple motor is that the stators 31, 32 comprise a plurality of separate coil cores, each with a rod-shaped longitudinal leg extending from a first end to a second end in the axial direction A, all first ends of which are connected by a yoke. Furthermore, each coil core comprises a transverse leg located at the second end of its respective longitudinal leg and extending radially, i.e., perpendicular to the axial direction A and thus perpendicular to its respective longitudinal leg. Each transverse leg extends radially inward, i.e., toward its respective rotor 214, 224. Thus, each coil core has an L-shaped design, with the longitudinal legs forming the longer legs of the L extending in the axial direction A and the transverse legs forming the shorter legs of the L, extending radially toward the rotors 214, 224 and perpendicular to the longitudinal legs.

[0062] The radially inner ends of the lateral legs form respective stator poles arranged in a ring around the respective recesses 33, 34 within which the rotors 214, 224 reside. In operation, when the rotors 214, 224 are not deflected from their nominal position, the stator poles and the magnetically active cores 215, 225 are at the same height in the axial direction A.

[0063] The parallel longitudinal legs of the coil cores, all extending parallel to the axial direction A and surrounding the rotor 214 or 224, are reminiscent of the pillars of a temple, hence the name temple motor.

[0064] Each stator 31, 32 further comprises a number of windings for generating an electromagnetic rotating magnetic field, whereby the respective rotor 214, 224 can be magnetically driven and magnetically levitated without contact with respect to the stator 31 or 32. The windings are, for example, designed as individual coils, one coil for each longitudinal leg of the stators 31, 32. Each coil is arranged around the respective longitudinal leg with the coil axis parallel to the axial direction A.

[0065] Each temple motor is designed according to the bearingless motor principle, which means that during operation of the pump device 1, the magnetically active cores 215, 225 of the rotors 214, 224 respectively interact with the stators 31, 32 respectively according to the above-mentioned bearingless motor principle, and each rotor 214, 224 can be magnetically driven and magnetically levitated without contact with respect to the respective stators 31, 32 respectively.

[0066] The principle of bearingless motors is already sufficiently well known to those skilled in the art, so a more detailed explanation of their function is no longer necessary. The principle of bearingless motors means that the rotors 214, 224 are magnetically driven and magnetically suspended, and the stators 31, 32 are designed as support and drive stators, which are both electrically driven and magnetically suspended stators. To this end, the stators 31 and 32 each have windings by which both the drive and support functions are realized. An electromagnetic rotating magnetic field can be generated by the windings, which, on the one hand, exert a torque on the magnetically active cores 215, 225 of the rotors 214, 224, causing the rotors to rotate about the axial direction A, and, on the other hand, exert a freely adjustable shear force on the magnetically active cores 215, 225 of the rotors 214, 224, thereby allowing the radial position of the rotors, i.e., their position in a radial plane perpendicular to the axial direction A, to be actively controlled or adjusted. In the case of a bearingless motor, in contrast to conventional magnetic bearings, magnetic levitation and motor drive are achieved by an electromagnetic rotating magnetic field that exerts a torque and a configurable shear force on the magnetically active core of the rotor. The rotating magnetic field required for this can be generated using separate coils, or it can be generated by mathematically superposing the required magnetic flux, in this case using a single coil system. Therefore, in the case of a bearingless motor, it is not possible to divide the magnetic flux generated by the windings of the stators 31, 32 into an electromagnetic flux that only allows the rotors 214, 224 to be driven and an electromagnetic flux that only allows the rotors 214, 224 to be magnetically levitated.

[0067] According to the bearingless motor principle, at least three degrees of freedom of the rotors 214, 224 can be actively adjusted: their position in the radial plane and their rotation about the axial direction A. With respect to axial distortion of the rotors in the axial direction A, the magnetically active cores 215, 225 of the rotors 214, 224 are passively magnetically stabilized by reluctance forces. That is, the rotors cannot be actively adjusted. With respect to the remaining two degrees of freedom, namely tilting with respect to a radial plane perpendicular to the rotation axes A1, A2, the rotors 214, 224 are also passively magnetically stabilized. Thus, due to the interaction between the magnetically active cores 215, 225 and the stators 31, 32, the rotors 214, 224 are passively magnetically levitated, i.e., passively magnetically stabilized, with respect to tilting in the axial direction A (a total of three degrees of freedom), and actively magnetically levitated in the radial plane (two degrees of freedom). In this manner, each rotor 214, 224 can be magnetically driven to rotate about its respective axis of rotation A1, A2 in a contactless manner, and can be magnetically levitated relative to its respective stator 31, 32 in a contactless manner.

[0068] It is an essential aspect of the pump device 1 according to the invention that a separate control device 41, 42 is provided for each stator 31, 32, i.e. a first control device 41 for the first stator 31 and a second control device 42 for the second stator 32. Each control device 41, 42 is designed to allow independent activation of the respective stator 31, 32.

[0069] Therefore, in principle, the first control device 41 does not need any information from the second control device 42 to operate the first stator 31 and the first rotor 214 according to the principles of a bearingless motor. Conversely, the second control device 42 does not need any information from the first control device 41 to operate the second stator 32 and the second rotor 224 according to the principles of a bearingless motor.

[0070] This means that if one of the control devices 41 or 42 fails, the pump device 1 is still operational, as the operation of the pump device 1 can be maintained by the other control device 42 or 41. The pump device 1 according to the invention can therefore be designed with hot redundancy.

[0071] Each control device 41 or 42 is preferably designed as an electronic board arranged below and fixed to the respective stator 31, 32 according to the diagram in Figure 1. Each electronic board comprises all components necessary for the operation of the respective bearingless motor, such as power electronics for actuating the windings, as well as the necessary evaluation, regulating and actuating components.

[0072] Furthermore, for each control device 41, 42, a power supply 51, 52 is provided for powering, preferably supplying electricity, to the respective control device 41, 42, i.e. a first power supply 51 for powering the first control device 41 and a second power supply 52 for powering the second control device 42. The first power supply 51 is connected to the first control unit 41 via a first supply line 101, and the second power supply 52 is connected to the second control unit 42 via a second supply line 102.

[0073] The power supplies 51, 52 are preferably located within the housing 35 of the stator.

[0074] Each power supply 51, 52 comprises a main energy source 511, 521 and an emergency energy storage device 512, 522. The main energy sources 511, 521 can, for example, each be designed as a power supply unit that receives power from an external power supply system. The emergency energy storage devices 512, 522 can, for example, each be designed as an accumulator or battery that still provides energy when the power supply unit is not connected to the external power supply system or when the power supply unit fails. This accumulator or battery is very advantageous, for example, when a patient is connected to the pump device 1 and has to be transported from one place to another.

[0075] In another embodiment, a single common power source is provided, supplying electrical energy to both control units 41, 42. Even in such an embodiment, the common energy supply comprises both a main energy source designed as a power supply unit that can be connected to an external power system, and an accumulator or battery as an emergency energy storage device.

[0076] The pump device 1 further comprises at least one sensor 6, by means of which operating parameters of the pump device 1 can be determined. The sensor 6 is, for example, a flow sensor 61, by means of which the flow rate of a fluid through the pump device 1 can be determined. For example, the flow sensor 61, designed as an ultrasonic flow measurement device, can be arranged at or near the second outlet 222. The flow sensor 61, or more generally the sensor 6, can be part of the reusable device 3. Furthermore, the flow sensor 61, or more generally the sensor 6, can be part of the disposable device 2.

[0077] The sensor 6 is signal connected to the first control device 41 using a first signal connection 601 and to the second control device 42 using a second signal connection 602. This also ensures the mutual independence of the control devices 41, 42, as each control device 41, 42 receives signals from the sensor 6 independently of the other control device 42, 41.

[0078] A communication connection 12 is preferably provided, via which the two control devices 41 and 42 can exchange signals or information with each other. This communication connection 12 can be used, for example, so that each control unit 41, 42 can check that the other control unit 42, 41 or the other pump unit 22, 21 is functioning.

[0079] With the exception of the magnetically active cores 215, 225, the disposable device 2 is preferably made from one or more types of plastic. Specifically, the pump housings 213, 223, the inlets 211, 221, the outlets 212, 222, the connecting channel 23, the impellers 216, 226, the ridges 217, 227, and the covering of the magnetically active cores 215, 225 are made from plastic. Of course, not all components of the disposable device 2 need be made from the same plastic.

[0080] The choice of suitable plastic will naturally depend on the respective application, but suitable plastics are, for example, polyethylene (PE), polypropylene (PP), low density polyethylene (LDPE), ultra-low density polyethylene (ULDPE), ethylene vinyl acetate (EVA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyacrylic, polycarbonate (PC), and silicone.

[0081] In the following, a second embodiment of a pump device 1 according to the invention will be described on the basis of Figures 5 to 8, which show a second variant of the disposable device 2. As already mentioned, only the differences with respect to the first embodiment and the first variant will be discussed in more detail.

[0082] Figure 5 shows, in a view similar to Figure 1, a schematic cross-section of a second embodiment of a pump device 1 according to the invention, in section along the section line V-V in Figure 6. However, in Figure 5 the power supplies 51, 52 as well as the various connections in the stator housing 35 have been omitted, as they are designed in a similar way to the first embodiment.

[0083] Figure 6, similar to Figure 2, shows a schematic cross-sectional view of a second embodiment of a pump device 1 according to the invention along the section line VI-VI in Figure 5. Figure 7, similar to Figure 3, shows a schematic cross-sectional view of a second variant of a disposable device 2 along the section line VII-VII in Figure 8. Figure 8, similar to Figure 4, shows a schematic cross-sectional view of a second variant of a disposable device 2 along the section line VIII-VIII in Figure 7.

[0084] In a second variant of the disposable device 2, a disposable housing 28 is provided in which the pump units 21, 22 are arranged. The disposable housing 28 forms, for example, a cassette which can be inserted into the reusable device 3 as a disposable part or which can be separated from the reusable device 3 in a particularly simple manner.

[0085] As can be seen particularly in Figures 5 and 7, in the second variant of the disposable device 2, the connecting channel 23 is designed so that the fluid changes direction by a total of 270° with respect to the axial direction A between the first outlet 212 and the second inlet 221. The connecting channel 23 is designed approximately U-shaped. The connecting channel 23 initially extends downstream of the first outlet 212 perpendicular to the axial direction A, so that the discharge direction D (Figure 8) is perpendicular to the axial direction A. Subsequently, the connecting channel 23 bends upward by 90°. Here, "up" refers to the illustrations in Figures 5 and 7. Then, the connecting channel 23 bends right by 90°. Here, "right" refers to the illustrations in Figures 5 and 7. The connecting channel 23 is thereby again perpendicular to the axial direction A. Finally, the connecting channel 23 bends downward by 90°. Here, "down" refers to the illustrations in Figures 5 and 7. As a result, fluid flows in the axial direction A through the second inlet 221. As a result of this embodiment, in the use position shown in Figure 5, the rotation axes A1, A2 of the pump units 21, 22, respectively, are aligned vertically (in the direction of gravity), and the two pump units 21, 22 are positioned at the same height relative to the vertical, i.e., next to each other.

[0086] A reusable device 3 is adapted to this embodiment of the disposable device 2 .

[0087] Figure 9 shows a schematic cross-sectional view of a third embodiment of a pump device 1 according to the invention in a cross-section similar to Figure 5. The third embodiment of a pump device 1 according to the invention comprises a disposable device 2 designed according to the second variant of the disposable device 2. It should be understood that the third embodiment of a pump device 1 according to the invention can also be provided in an analogous manner as a disposable device 2 designed according to the first variant of the disposable device 2.

[0088] The essential difference from the previous embodiments is that in this third embodiment of the pump device 1 according to the invention, the reusable device 3 is designed such that the rotors 214, 224 of the disposable device 2 rotate about rotation axes A1, A2, respectively, in the operating state, and that the rotation axes A1 and A2 form an angle with the vertical that is smaller than 90° and different from zero. This means that the two rotation axes A1 and A2 are inclined with respect to the vertical in the operating state at an angle different from 0° and 90°. The vertical line corresponds to the vertical direction, i.e., the direction in which gravity acts.

[0089] In this embodiment, it is particularly easy to prevent gas bubbles, e.g. air bubbles, from depositing in particular in the connecting channel 23 during priming of the pump device 1, which could cause considerable damage during operation, e.g. to a patient connected to the pump device 1. For example, the deposition of gas bubbles, which is desirable as well as in the siphon, is efficiently prevented by the inclined position of the two pump units 21, 22 with respect to the vertical and horizontal directions.

[0090] 10 to 14, a fourth embodiment of a pump device 1 according to the invention is described, which has a third variant of the disposable device 2. Again, only the differences with respect to the previous embodiments and variants will be discussed in more detail.

[0091] It will be understood that the fourth embodiment of the pump device 1 according to the present invention may also be provided in a similar manner as the disposable device 2, designed according to the first or second variant of the disposable device 2.

[0092] FIG. 10 is a view similar to FIG. 1 and shows a schematic cross-sectional view of a fourth embodiment of a pump device 1 according to the present invention, taken along the section line X-X in FIG. 11. FIG. 11 is a view similar to FIG. 6 and shows a schematic cross-sectional view of a fourth embodiment of a pump device 1 according to the present invention, taken along the section line XI-XI in FIG. 10. FIG. 12 is a view similar to FIG. 7 and shows a schematic cross-sectional view of a third variant of a disposable device 2, taken along the section line XII-XII in FIG. 13. FIG. 13 shows a schematic cross-sectional view of the third variant of a disposable device 2, taken along the section line XIII-XIII in FIG. 12, and FIG. 14 shows a schematic cross-sectional view of the third variant of a disposable device 2, taken along the section line XIV-XIV in FIG. 12.

[0093] In a fourth embodiment of the pump device 1 according to the invention, the reusable device 3 is designed in a similar manner to the third embodiment such that the rotors 214, 224 of the disposable device 2 rotate about axes of rotation A1, A2, respectively, in the operating state, and the axes of rotation A1 and A2 form an angle with the vertical that is smaller than 90° and different from zero, which means that the two axes of rotation A1 and A2 are inclined with respect to the vertical in the operating state at an angle different from 0° and different from 90°.

[0094] The disposable device 2 is designed according to a third variant in which the fluid flow in the disposable device 2 is similar to that of the second variant of the disposable device 2. Of course, the third variant of the disposable device 2 can also be designed in an analogous manner in which the fluid flow occurs in a manner similar to the first variant, i.e. in such a way that the fluid is redirected by 90° relative to the axial direction A between the first outlet 212 and the second inlet 221.

[0095] In a third variant, the disposable device 2 comprises three parts 291, 292, 293, each of which is manufactured separately and then joined together in a joining process. The three parts 291, 292, 293 are designed so that their respective boundary surfaces are aligned perpendicular to the axial direction A. The first part 291 has two ridges 217, 227 by means of which the disposable device 2 can be inserted into the reusable device 3. The second part 292 has an area adjacent to the first part 291 in the axial direction A and defines the upper boundary of the cavity in which the two rotors 214 and 224 are located. Here, "upper" refers to the illustration in FIG. 12. The third part 293 forms the area that defines the boundary of the disposable device 2 on the side facing away from the reusable device 3 in the axial direction A and includes the first inlet 211 and a portion of the connecting channel 23.

[0096] This embodiment is particularly advantageous from a manufacturing point of view: each of the parts 291, 292, 293 can be manufactured in a simple manner, preferably by an injection molding process, after which the three parts 291, 292, 293 are firmly joined together.

[0097] In Figures 13 and 14, a first part 291 and a second part 292 are shown. In these cross-sectional views, the cross-section is made perpendicular to the axial direction at the interface between the first part 291 and the second part 292 (Figure 13) or the interface between the second part 292 and the third part 293 (Figure 14). The location of the cross-section is shown in Figure 12. This means that Figure 13 shows a plan view of the first part 291 and Figure 14 shows a plan view of the second part 292, respectively, from the axial direction A.

[0098] As already mentioned, each of the three parts 291, 292, 293 is preferably an injection-molded part. To manufacture the disposable device 2, the following procedure is preferred: the three parts 291, 292, 293 are manufactured from plastic by an injection-molding process. Subsequently, the rotor 214 or 224 is inserted into the two ridges 217, 227 of the first part 291, respectively. The second part 292 is then placed on the first part 291 and tightly and sealingly connected to the first part 291 in a bonding process. This bonding process can be, for example, an adhesive process, for example, bonding with an adhesive that can be cured by ultraviolet light. Furthermore, the bonding process can be a welding process, for example, infrared welding, laser welding, or ultrasonic welding. The third part 293 is connected to the second part 292 in a similar manner. Thus, in this variant, the connecting channel 23 and the pump housings 213, 223 are respectively formed by cavities provided in the three parts 291, 292, 293. Of course, it is also possible to first place all parts 291, 292, 293 one on top of the other and only then firmly connect the three parts 291, 292, 293 by a welding or adhesive process.

[0099] 12, a measurement channel 7 or several measurement channels may also be provided in the disposable device 2 extending from outside the disposable device 2 to one of the two inlets 211, 221 or one of the outlets 212, 222. A sensor (not shown) may be disposed in such a measurement channel and used to determine an operating parameter, for example, the pressure or flow rate through the pump device 1.

[0100] In a fourth embodiment of the pump device 1 according to the invention, a higher-level control unit 40 (FIG. 10) is further provided in the stator housing 35. Of course, such a higher-level control unit 40 can also be provided in the previous embodiments.

[0101] This upper control unit 40 is signal-connected to the first control device 41 via a first connection 401 and to the second control device 42 via a second signal connection 402, so that the upper control unit 40 can exchange signals or information with both control devices 41, 42.

[0102] Furthermore, the disposable device 2 comprises an identification element 81, which enables the disposable device 2 to identify itself to the reusable device 3. The identification element 81 specifically stores unique data of the disposable device 2, such as calibration data, which enables the reusable device 3 to identify the disposable device 2, and the unique characteristics of each disposable device 2 can be transmitted to the reusable device 3.

[0103] For this purpose, the reusable device 3 preferably comprises a recognition element 82 designed to be able to identify the respective disposable device 2 or its characteristics by interaction with the identification element 81 .

[0104] Preferably, both the identification element 81 and the recognition element 82 are each designed as an RFID (Radio Frequency Identification) element. In another embodiment, the identification element 81 and / or the recognition element 82 may comprise a barcode, in particular a two-dimensional or three-dimensional barcode.

[0105] The recognition element 82 is signal-connected to the upper control unit 40 via an identification connection, thereby enabling the upper control unit 40 to receive respective unique data, e.g., calibration data, from and / or transmit data to the disposable device 2 inserted into the reusable device 3.

[0106] Furthermore, two pressure sensors 621 and 622 are provided, the first pressure sensor 621 being arranged so that it can be used to determine the pressure of the fluid at the first inlet 211 and the second pressure sensor 622 being arranged so that it can be used to determine the pressure at the second outlet 222. Thus, the pressure difference generated by the pump device 1 can be determined using the two pressure sensors 621 and 622.

[0107] The two pressure sensors 621 and 622 are signal-connected to a higher-level control unit 40 via connections 611 and 612. Additionally, or if a higher-level control unit 40 is not provided, the pressure sensors 621 and 622 can be signal-connected to either of the control units 41 and 42. This is shown in Figure 10 only for the pressure sensor 622 in the second outlet 222 with the dashed connections 623 and 624.

[0108] The third part 293 may have one protrusion 294 at the end facing the second part 292, or several protrusions 294, for example one at each corner, which are designed to interact with holding elements 394 on the surface of the stator housing 35 (see Figure 11). Preferably, the protrusions 294 of the disposable device 2 interact with the holding elements 394 of the reusable device 3 in the form of a snap connection, which prevents unintentional separation of the disposable device 2 and the reusable device 3.

[0109] In the following, the method according to the invention for operating the pump device 1 according to the invention will now be discussed in more detail. It should be noted that the pump device 1 according to the invention can be designed according to any of the above-described embodiments or variants.

[0110] In the method according to the invention, a desired value of an operating parameter of the pump device 1 is predetermined in each control device 41, 42. The actual value of this operating parameter is determined using a sensor and the actual value is transmitted to each control device 41, 42.

[0111] 15 shows in a symbolic diagram an embodiment of a pump device 1 according to the invention with two pump units 21, 22, two control devices 41, 42 and a communication connection 12 between the two control devices 41, 42. Furthermore, a first connection 43 and a second connection 44 are symbolically shown by dashed lines. The first connection 43 indicates the communication of the first control device 41 with the first pump unit 21, and the second connection indicates the communication of the second control device 42 with the second pump unit 22.

[0112] The method according to the invention is based in principle on the fact that for a given pressure difference to be generated by the pump device 1, two pump units 21, 22 connected in series are used in normal, i.e. fault-free, operation, so that the respective rotational speeds of the two pump units 21, 22 are increased by a factor of 1 compared to the situation in which only one pump unit 21 or 22 is used to generate the same pressure difference.

number

[0113] If, for some reason, one of the two pump units 21, 22 or the control units 41, 42 fails, the rotation speed of the other pump unit 22 or 21 will be reduced by a factor of 1.

number

[0114] 15, the arrow with the reference symbol N indicates the desired value of the rotational speed of the pump units 21, 22. This desired value N is transmitted to both control devices 41, 42. Each control device 41, 42 receives, via a connection 43 or 44 with its assigned pump unit 21 or 22, the actual value of the current rotational speed of the motor by which the respective electromagnetic rotary drive rotates. This rotational speed is determined in the bearingless motor, for example by means of a Hall sensor.

[0115] The unreferenced arrows on the pump units 21, 22 symbolize the fluid to be transported.

[0116] The two control devices 41, 42 can exchange control signals with each other, in particular the actual values ​​of the rotational speeds of their respective motors, via the communication connection 12. Optionally (not shown in FIG. 15 ), there may be a further signal connection via which the first control device 41 receives the actual value of the rotational speed of the motor of the second pump unit 22 directly, i.e. not via the second control device 42, and the second control device 42 receives the actual value of the rotational speed of the motor of the first pump unit 21 directly, i.e. not via the first control device 41.

[0117] A basic embodiment of the above is shown in the flow chart of Figure 16. In step 10, each control device 41, 42 reads the desired value of the rotational speed of the pump, i.e. the desired value of the rotational speed of the pump device 1.

[0118] In step 11, the two control devices 41 and 42 communicate with each other via the communication connection 12 to determine whether the bearingless motor of the respective other pump unit 21 or 22 is operating without fault. Many error detection procedures are known to those skilled in the art for such verification.

[0119] If it is determined in step 11 that the bearingless motors of both pump units 21, 22 are operating without any faults, then in step 12 it is determined that the actual values ​​of the motor rotation speeds of both pump units 21, 22 are less than the desired values ​​of the pump rotation speeds by a factor of 1.

number

[0120] If it is determined in step 11 that one of the two bearingless motors of the two pump units 21, 22 is not operating, then in step 13 the desired value of the motor rotation speed of the other bearingless motor is set to the value of the pump rotation speed.

[0121] Then, in step 14, after step 12 or step 13, it is checked whether the difference between the actual value and the desired value of the motor rotation speed is within a predetermined tolerance.

[0122] Then, in step 15, the two control devices 41 and 42 exchange the results of the verification in step 14 via the communication connection 12.

[0123] The procedure then resumes at step 10.

[0124] In order to ensure a particularly high operational reliability, all connections via which information is exchanged, ie for example the communication connection 12, are preferably designed redundantly.

[0125] FIG. 17 shows a first variant of the embodiment of the method according to the invention in a symbolic diagram similar to FIG. 15. In this first variant, the flow rate through the pump device 1 is used as the operating parameter. For this purpose, a flow rate sensor 61 is provided, preferably located near the second outlet 222. As already mentioned above, the flow rate sensor 61 is signal-connected to the first control unit 41 via a first signal connection 601 and to the second control unit 42 via a second signal connection 602. Thus, the flow rate sensor 61 provides the two control devices 41, 42 with the actual value of the flow rate, which can then be compared with the desired value of the flow rate. In the event of a discrepancy, the actual value of the flow rate can be adjusted to the desired value. For this adjustment, the communication connection 12 between the two control devices 41, 42 is not absolutely necessary. If one of the control devices 41 or 42 or one of the pump units 21 or 22 fails, this will result in a change in the actual value of the flow rate, which will be transmitted to both control devices 41, 42 via signal connections 601, 602. The still functioning control device 41 or 42 or control device 41, 42 of the still functioning pump unit 21 or 22 will then change the rotational speed of the associated bearingless motor so that the actual value of the flow rate is returned to the desired value of the flow rate.

[0126] FIG. 18 shows a second variant of the embodiment of the method according to the invention in a symbolic diagram similar to FIG. 15. In this second variant, the flow rate through the pump device 1 is again used as the operating parameter. In contrast to the first variant, in the second variant, the flow rate measurement for determining the actual value of the flow rate is designed to be redundant. For example, as shown in FIG. 18, this can be realized by providing a second flow rate sensor 63 in addition to the flow rate sensor 61. Each flow rate sensor 61, 63 is then signal-connected to each control device 41, 42. The flow rate sensor 61 is signal-connected to the first control device 41 or the second control device 42 via signal connections 601, 602, and the second flow rate sensor 63 is signal-connected to the first control device 41 or the second control device 42 via signal connections 603 and 604. Alternatively, instead of the two flow sensors 61, 63, it is of course also possible to provide only one flow sensor, which is designed redundantly to allow two separate flow measurements, for example by means of several ultrasonic transducers.

[0127] Figure 19 shows, in a symbolic diagram similar to Figure 15, a third variant of the embodiment of the method according to the invention. In this third variant, the pressure difference generated by the pump device 1 is used as the operating parameter. For this purpose, two pressure sensors 621 and 622 are provided (see also Figure 10), the first pressure sensor 621 being arranged so that it can be used to determine the pressure of the fluid at the first inlet 211, and the second pressure sensor 622 being arranged so that it can be used to determine the pressure at the second outlet 222. Thus, the two pressure sensors 621 and 622 can be used to determine the pressure difference generated by the pump device 1. Each of the two pressure sensors 621 and 622 is signal-connected to both the control devices 41 and 42, respectively. The pressure sensor 622 is signal-connected to the first control unit 41 or the second control unit 42 via connection 623 or 624. The pressure sensor 621 is signal connected to the first control device 41 or the second control device 42 via a connection 625 or 626 .

[0128] Thus, the two pressure sensors 621 and 622 can transmit the actual value of the pressure at the first inlet 211 and the actual value of the pressure at the second outlet 222 to both control devices 41, 42, respectively. The control devices 41, 42 then determine the actual value of the pressure difference generated by the pump device 1 and compare the actual value of the pressure difference with the desired value of the pressure difference. If there is a discrepancy between the actual value of the pressure difference and the desired value, exceeding a pre-determinable tolerance, the actual value of the pressure difference is adjusted to the desired value. For this adjustment, the communication connection 12 between the two control devices 41, 42 is not absolutely necessary. If one of the control devices 41 or 42 or one of the pump units 21 or 22 fails, this will result in a change in the actual value of the pressure difference, which can be detected by both control devices 41, 42. The still functioning control device 41 or 42 or control devices 41, 42 of the still functioning pump unit 21 or 22 will then change the rotational speed of the bearingless motor involved so that the actual value of the pressure difference is returned to the desired value of the pressure difference.

[0129] FIG. 20 shows a fourth variant of the embodiment of the method according to the invention in a symbolic diagram similar to FIG. 15. In this fourth variant, two operating parameters are used: the pressure difference generated by the pump device 1 and the flow rate through the pump device 1. This fourth variant is therefore a combination of the third variant (FIG. 19) with the second variant (FIG. 18) or with the first variant (FIG. 17). In this fourth variant, both pressure sensors 621 and 622, with which the pressure difference generated by the pump device 1 can be determined, and a flow rate sensor 61, with which the flow rate through the pump device 1 can be determined, are therefore provided. In this case, either only one flow rate sensor 61 can be provided, as explained in FIG. 17, or two flow rate sensors 61, 63 (see FIG. 18), i.e., a redundantly designed flow rate sensor 61 can be provided.

[0130] In particular, with regard to the operating parameters pressure difference and flow rate, it is also possible that such operating parameters can be determined alternatively or additionally from other operating parameters of the pump device 1 .

[0131] For example, the flow rate through the pump device 1 can be determined from the rotational speed and generated torque of the bearingless motor. Since a bearingless motor has no friction, as for example mechanical bearings, the torque of a bearingless motor can be known very accurately from an electrical value.

[0132] The torque at various rotational speeds can then be expressed as a function that depends on the fluid density, the fluid viscosity (dynamic viscosity), and the flow rate. Using a reference fluid, e.g., human or animal blood, at a temperature of 37°C, a family of characteristic curves showing the dependence of flow rate on torque can then be experimentally recorded at various rotational speeds. As already mentioned, this family of characteristic curves can then be represented by a family of functions, thus determining the coefficients of the parameters in the functional correlations. These parameters or functional correlations can then be stored in the control devices 41, 42, so that during operation, the actual value of the flow rate can be determined from the actual value of the torque. Alternatively, it is of course possible to store the entire family of characteristic curves, for example, as a look-up table in the two control units 41, 42.

[0133] Depending on which values ​​are known from the family of "torque vs. flow" characteristic curves, it is also possible to determine other values ​​of the fluid. For example, in the family of "torque vs. flow" characteristic curves, the torque at zero flow rate is proportional to the viscosity. This means, for example, that if the flow rate is determined by measurement, the viscosity of the fluid can be determined. In this way, it is also possible to generate a family of "torque vs. flow" characteristic curves, for example, in which viscosity is a parameter, i.e., different curves of the characteristic diagram are for different viscosities.

[0134] The pump device 1 according to the invention or the method according to the invention are particularly suitable for applications in which highly sensitive substances are transported, such as blood or biotechnological fluids containing cells, proteins or other sensitive components, with typical features being mentioned here in applications in extracorporeal membrane oxygenation (ECMO) for maintaining lung function, in heart-lung machines, in biopharmaceutical production processes, e.g., filtration processes in which desired substances (e.g., proteins) are permeated out of fluids produced in bioreactors, and in perfusion processes in the biotechnological or biopharmaceutical industry.

[0135] In the previous description, a pump device 1 is described which comprises two pump units 21, 22. However, in such an embodiment of the pump device according to the invention, it is also possible that more than two pump units, for example three or even more pump units, are connected one behind the other in series.

Claims

[Claim 1] A pump device for transporting a fluid, comprising a disposable device (2) designed for single use only, and a reusable device (3) designed for multiple use, wherein the disposable device (2) comprises two pump units (21, 22) designed to be inserted into the reusable device (3) and arranged in series one after the other, each pump unit (21, 22) comprising a rotor (214, 224) for transporting the fluid, each rotor (214, 224) designed as a rotor of a bearingless motor, which can be magnetically levitated without contact and driven to rotate around an axial direction (A) without contact, and the reusable device (3) comprises a rotor (214, 224) for transporting the fluid, the rotor (214, 224) being designed as a rotor of a bearingless motor, which can be magnetically levitated without contact and driven to rotate around an axial direction (A) without contact, a stator (31, 32) for each rotor (214, 224) designed to receive the disposable device (2) and forming, together with the rotor (214, 224), an electromagnetic rotary drive for rotating the rotor (214, 224) about the axial direction (A), each stator (31, 32) designed as a support and drive stator by which the rotor (214, 224) can be magnetically driven without contact and magnetically levitated relative to the stator (31, 32) without contact, and a separate control device (41, 42) designed to separately activate each stator (31, 32) is provided for each stator (31, 32).

Images