Device for changing pump unit of centrifugal pump, and centrifugal pump

Abstract

To provide a device for changing a pump unit of a centrifugal pump, which enables very simple, quick and safe separation of the pump unit from a stator.SOLUTION: In the present invention, a centrifugal pump 200 has: a pump unit 50; and a stator 100 extending in an axial direction A from a first axial end 101 to a second axial end 102. A cup-shaped recess 121, into which the pump unit can be inserted, is provided at the first axial end, and the pump unit has a pump housing 52 having a cup 531 that can be inserted into the cup-shaped recess 121. A rotor 51 for transporting fluid is disposed in the pump housing 52. A device 1 for changing the pump unit has an actuation device 6 capable of applying mechanical force to the pump unit, in which the mechanical force acts in the axial direction A and is directed to separate the pump unit from the stator in the axial direction A.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a device for replacing a pump unit of a centrifugal pump according to the preamble of the independent patent claim. The present invention further relates to a centrifugal pump having such a device.

Background Art

[0002] Centrifugal pumps having a pump unit and a stator are known, in which a rotor is provided in the pump unit, and the rotor forms an impeller of the centrifugal pump. The pump unit can be inserted into the stator and forms an electromagnetic rotary drive unit together with the stator. In the pump unit, the rotor can be magnetically supported without contact and driven to rotate about the axial direction without contact by the stator. Such centrifugal pumps are sold by the applicant under the product name Levitronix® BPS pump, for example.

[0003] In these centrifugal pumps, a cup-shaped recess is provided in one of the axial ends of the stator, and the pump unit can be inserted into this cup-shaped recess. The pump unit has a pump housing having a cup that can be inserted into the cup-shaped recess of the stator.

[0004] The stator and the rotor form an electromagnetic rotating drive unit, and this electromagnetic rotating drive unit is designed according to the principle of a bearingless motor. The term "bearingless motor" refers to an electromagnetic rotating drive unit that can magnetically support the rotor completely with respect to the stator and does not have any separate magnetic bearings. Therefore, the stator is designed as a bearing and a drive stator, and it is both an electrical drive stator and a magnetic bearing stator. The electrical winding of the stator can generate a rotating magnetic field. The rotating magnetic field, on the one hand, applies torque to the rotor, resulting in the rotation of the rotor around a desired rotation axis defined by the axial direction, and on the other hand, applies an arbitrarily adjustable lateral force to the rotor so that its radial position can be actively controlled or adjusted. Therefore, the three degrees of freedom of the rotor, that is, the rotation of the rotor and the radial position of the rotor (two degrees of freedom), can be actively adjusted. With regard to a further three degrees of freedom, that is, the position of the rotor in the axial direction and the inclination (two degrees of freedom) with respect to a radial plane perpendicular to the desired rotation axis, the rotor is passively magnetically supported or magnetically stabilized by magnetic reluctance, that is, it cannot be controlled. The characteristic of the complete magnetic bearing of the rotor is that there is no separate magnetic bearing, and thus the bearingless motor is named after this. In the bearing and drive stator, the bearing function cannot be separated from the drive function.

[0005] A specific advantage of such a centrifugal pump is the design of the rotor as an integral rotor, where the rotor is a rotor of electromagnetic rotation drive, and thus is also a rotor of electromagnetic drive and magnetic bearing, and is also a rotor of a pump for conveying fluid. This brings the advantage of a very compact and space-saving design.

[0006] Centrifugal pumps having a rotor that is magnetically supported and driven without contact, for example centrifugal pumps designed according to the principle of a bearingless motor, have been proven in many applications. Due to the absence of mechanical bearings, such centrifugal pumps are suitable for applications in which very sensitive substances are conveyed, such as blood pumps, or for applications with very high purity requirements, such as the semiconductor industry, the pharmaceutical industry, the biotechnology industry, or for applications in which abrasive or erosive substances are conveyed that very rapidly destroy mechanical bearings, such as pumps for slurries, sulfuric acid, phosphoric acid, or other chemicals in the semiconductor industry.

[0007] In the biotechnology or pharmaceutical industry, for example, such centrifugal pumps are used in relation to bioreactors, for example to convey fluid to or from a bioreactor. In particular, in such applications, sterility is very important, for example in processes in which biological activity occurs. Sterilizing the device, for example by steam sterilization, is very often a time-consuming and cost-intensive factor. For this reason, there is currently an increasing tendency to design the components of each device as disposable parts in order to avoid or minimize time-consuming sterilization processes. In particular, those components that come into direct contact with biological substances during the process are often designed as disposable parts. The term disposable part refers to a part or component that can only be used once according to its intended use. After use, the disposable part is discarded and replaced with a new, i.e., unused, disposable part for the next application.

[0008] Accordingly, centrifugal pumps are known in which the pump unit is designed as a disposable part. After each application, the pump unit is separated from the stator and replaced with a new, unused pump unit. With regard to the highest possible efficiency, it is desirable that the pump unit can be replaced in a very simple and rapid manner with as little effort as possible.

[0009] For this reason, for example, it is known to lock a pump unit in a cup-shaped recess of a stator by means of a bayonet lock. In order to replace the pump unit, in that case, the bayonet lock is released, the pump unit is replaced with a new pump unit, and the bayonet lock is locked again.

[0010] Even if it has been demonstrated that this design is actually very successful, there is a need for improvement, especially with regard to such centrifugal pumps designed for very high power, having an electric rotary drive designed for example for powers above 4 kW. Such centrifugal pumps often have very powerful permanent magnets arranged in the rotor and / or stator. Especially in such a design, a very large magnetic force acts between the rotor and the stator. Even when the windings of the stator are no longer energized by current, a passive magnetic force, i.e. for example a magnetic reluctance force, continues to act. In that case, when the pump unit is to be replaced, these very large magnetic forces between the rotor and the stator have to be overcome. In this case, there is a very serious risk that the operator will be injured or the components of the centrifugal pump will be damaged when changing the pump unit. Since the magnetic forces are often very large, it is hardly possible or only possible with great effort to separate the pump unit from the stator by hand. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0011] Accordingly, from this prior art, one object of the present invention is to propose an apparatus for replacing a pump unit of a centrifugal pump having a rotor that is non-contact magnetically driven and magnetically levitated, which enables very simple, rapid and safe separation of the pump unit from the stator. In addition, one object of the present invention is to propose a centrifugal pump having such an apparatus for replacing the pump unit. MEANS FOR SOLVING THE PROBLEM

[0012] The subject matter of the present invention for achieving this purpose is characterized by the features of the independent patent claims.

[0013] According to the present invention, there is provided an apparatus for replacing a pump unit of a centrifugal pump, the centrifugal pump having a pump unit and a stator extending axially from a first axial end to a second axial end, a cup-shaped recess being provided at the first axial end, the pump unit being insertable into the cup-shaped recess, the pump unit having a pump housing with a cup that can be inserted into the cup-shaped recess of the stator, a rotor for conveying fluid being disposed within the pump housing, the rotor having a magnetically effective core, the rotor being rotatable about the axial direction, the stator being designed for non-contact magnetic drive and non-contact magnetic levitation of the rotor, and the rotor being at least axially magnetically stabilized passively with respect to the stator. The apparatus has an operating device that can apply a mechanical force to the pump unit, the mechanical force acting axially and being directed to axially separate the pump unit from the stator.

[0014] In the case of such an apparatus, the apparatus can apply a mechanical force to the pump unit axially, and the pump unit can be separated from the stator in a particularly simple manner with little manual labor by an operator. This results in a significant reduction in the risk of injury to the operator, and the pump unit is also reliably protected from damage. Further, the apparatus enables particularly rapid replacement of the pump unit, which is a particular advantage, for example, in applications in biotechnology where the pump unit is designed as a disposable part. The reason for this is that, particularly in such embodiments where the pump unit is designed as a disposable part, it is a substantial aspect that the pump unit can be replaced or exchanged as quickly as possible with little time taken.

[0015] However, even in applications where the pump unit is designed for multiple use or reuse, the easy and quick separability of the pump unit from the stator is an advantage, for example, when it is necessary to inspect, repair, or replace the pump unit or components of the pump unit. For example, such separability may be necessary to replace a rotor forming a wheel or impeller of a centrifugal pump.

[0016] Preferably, the device can be fixed to the stator or fixed relative to the stator.

[0017] Embodiments are possible where the device for replacing the pump unit is not only permanently attached to the stator, i.e., only when the pump unit is intended to be replaced. In other embodiments, the device is fixed to the stator only for the replacement process. After the pump unit has been replaced, the device is removed and separated from the stator. Embodiments are also possible where the device can be fixed relative to the stator, for example, by fixing the device and the stator to a common rail or the like.

[0018] According to a preferred embodiment, the actuating device is designed such that a mechanical force acts on a cup-shaped recess in the stator or on a cup of the pump housing. In that case, the actuating device abuts against the bottom of the cup or the bottom of the cup-shaped recess such that the pump unit is axially pushed out of the stator, either alone or together with the cup-shaped recess.

[0019] The actuating device has a piston that can be displaced axially, the piston can be inserted into an opening arranged centrally within the stator, and in a preferred embodiment, the displacement of the piston relative to the stator gives rise to a mechanical force that axially separates the pump unit from the stator. The centrally arranged opening preferably extends axially from the second axial end of the stator into a cup-shaped recess or into the cup of the pump unit. The piston is arranged within this centrally arranged opening and can be displaced axially relative to the stator. Thus, by displacing the piston, the pump unit is pushed axially out of the stator, either alone or together with the cup-shaped recess. When the piston acts directly on the cup of the pump unit, the cup-shaped recess is provided with an opening through which the piston can pass.

[0020] The axial displacement of the piston can be effected, for example, by means of a threaded crank, which is operated by hand or by a motor, for example a spindle motor.

[0021] The device has guide rails that can be fixed to the stator, on which axially displaceable support elements are arranged, and it is a preferred measure to protect the pump unit since the support elements tilt when the pump unit is separated from the stator. The guide rails, together with the support elements, protect against tilting of the pump unit axially both when the pump unit is inserted into the stator and when the pump unit is separated from the stator, ensuring that the pump unit cannot be twisted within the stator.

[0022] According to a further preferred embodiment, the actuating device is designed such that a mechanical force acts on a region of the pump housing that is arranged outside the cup-shaped recess of the stator. Thus, in this case, the force acting on the pump unit is applied to a region of the pump unit that is not arranged within the cup-shaped recess of the stator when the pump unit is inserted into the stator.

[0023] Of course, it is also possible to have such an embodiment in which forces acting on the pump unit are applied to both the region disposed within the cup-shaped recess of the stator and the region not disposed within the cup-shaped recess of the stator.

[0024] It is a further preferred measure that the actuating device has a spring element that can be inserted into an opening arranged centrally within the stator, and the spring element is designed such that when the pump unit is inserted into the cup-shaped recess, the spring element is axially tensioned. As long as the pump unit is fixed within the stator, the spring element is under tension. Next, when the pump unit is to be separated from the stator, this tension applied to the spring element is used to support or effect the separation of the pump unit from the stator.

[0025] Accordingly, the spring element is designed and arranged such that when the pump unit is inserted, i.e., when the pump unit is inserted into the stator against the force of the spring element, the spring element is tensioned. When the pump unit is inserted, the spring element has a damping effect, which has the advantage that it can reduce the strong magnetic force that tries to pull the pump unit into the stator. In this way, the pump unit can be inserted gently and carefully into the stator. In particular, it is possible to reliably avoid the pump unit hitting the stator violently during insertion. When the pump unit is separated from the stator, the tensioned spring element applies an axially acting force to the pump unit, and this force supports or effects the separation from the stator.

[0026] According to a preferred embodiment, the device has a mounting device that can be fixed to the first axial end of the stator. The mounting device has an annular base designed to surround the pump housing. To axially guide the pump housing into the cup-shaped recess of the stator, several guide elements are arranged on the base, and several attachment elements are provided to fix the pump housing. The mounting device has several elastic elements that apply axial tension when the pump unit is fixed within the stator.

[0027] When the pump unit is inserted into the stator, an elastic element, such as a spring, is tensioned, that is, the pump unit is inserted into the stator against the spring force of the elastic element. When the pump unit is separated from the stator, the elastic element provides a mechanical force that acts axially and attempts to push the pump unit out of the stator.

[0028] In a further preferred embodiment, the device has a mounting ring that can be fixed to the first axial end of the stator such that the mounting ring is arranged around the cup-shaped recess. A first guide rod and a second guide rod are arranged on the mounting ring, each extending axially. A pivotable holding device for holding the pump unit is provided on the first guide rod. The holding device can pivot to a holding position where it abuts against the second guide rod. At least one tension lever is provided. By operating the tension lever, the holding device can be displaced axially along the guide rod. In this embodiment, the mechanical force is generated by at least one tension lever, and this mechanical force can axially displace the pump unit along the guide rod.

[0029] In this case, it is preferable that a locking element is provided on one of the guide rods, and when the pump housing is arranged in the cup-shaped recess, the retaining device can be fixed to the guide rod by the locking element. By doing so, an unintentional separation of the pump unit from the stator is avoided.

[0030] In a further preferred embodiment, the device has a bayonet ring, which can be fixed to the first axial end of the stator such that the bayonet ring is arranged around the cup-shaped recess, and the bayonet ring is designed for a bayonet connection of the pump housing of the pump unit.

[0031] Preferably, the bayonet ring is designed such that the pump housing can be fixed in the bayonet ring by a rotational movement about the axis of the bayonet ring, a subsequent axial movement, and a subsequent rotational movement about the axis.

[0032] Preferably, a securing ring pin is provided on the bayonet ring, by which the pump unit can be fixed to the bayonet ring when the pump housing is arranged in the cup-shaped recess. By doing so, an unintentional separation of the pump unit from the stator is avoided.

[0033] Furthermore, a centrifugal pump for conveying fluid, having a pump unit and a stator extending axially from a first axial end to a second axial end, wherein a cup-shaped recess is provided at the first axial end, the pump unit can be inserted into the cup-shaped recess, the pump unit has a pump housing having a cup that can be inserted into the cup-shaped recess of the stator, a rotor for conveying fluid is disposed within the pump housing, the rotor has a magnetically effective core, the rotor and the stator together form an electromagnetic rotational drive unit, the stator is designed for non-contact magnetic drive and non-contact magnetic levitation of the rotor, and the rotor is at least axially magnetically stabilized passively, is proposed by the present invention. An apparatus for replacing the pump unit is provided, and the apparatus is designed in accordance with the present invention.

[0034] According to a preferred embodiment, the apparatus for replacing the pump unit is designed such that the pump unit can be removed from the centrifugal pump in each case after the pump unit has been replaced.

[0035] Of course, embodiments are also possible in which the apparatus for replacing the pump unit is always fixed to the centrifugal pump, i.e., not only when the pump unit is replaced.

[0036] In a particularly preferred embodiment of the centrifugal pump, the electromagnetic rotational drive unit is designed as a temple motor, the stator has a plurality of coil cores, each of the coil cores has a longitudinal leg extending axially from a first end to a second end, and a transverse leg disposed at the second end of the longitudinal leg and extending in a radial direction perpendicular to the axial direction, the coil cores are arranged around the rotor in the circumferential direction such that the rotor is disposed between the transverse legs of the coil cores, and at least one concentrated winding is provided on each longitudinal leg, and the winding surrounds each longitudinal leg.

[0037] Further advantageous measures and embodiments of the present invention are apparent from the dependent claims.

[0038] Hereinafter, the present invention will be described in more detail with reference to embodiments and with reference to the drawings.

Brief Description of the Drawings

[0039]

Figure 1a

Figure 1b

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0040] An apparatus for replacing the pump unit of a centrifugal pump is provided by the present invention. For better understanding, an example of a centrifugal pump suitable for the apparatus according to the present invention will first be described with reference to FIGS. 1a, 1b and 2.

[0041] FIG. 1a shows, in a partial cross-sectional perspective view, an example of a centrifugal pump known per se, which is shown in its entirety by reference numeral 200. In a depiction similar to FIG. 1a, FIG. 1b shows a modified example of the centrifugal pump 200. The centrifugal pump 200 has a pump unit 50 and a stator 100 extending in the axial direction A from the first axial end 101 to the second axial end 102. The stator 100 further includes a stator housing 120, which is preferably designed as a hermetically sealed stator housing 120 to hermetically enclose other components of the stator 100. A cup-shaped recess 121 is provided at the first axial end 101 of the stator 100, and the pump unit 50 can be inserted into this cup-shaped recess 121.

[0042] Figure 2 shows a cross-sectional view of the pump unit 50 of the centrifugal pump 200 according to FIG. 1a or FIG. 1b. Inside the pump unit 50, a rotor 51 forming a wheel or impeller is arranged, and the fluid is conveyed by this wheel or impeller. When the pump unit 50 is inserted into the cup-shaped recess 121 of the stator 100, the stator 100 forms, together with the rotor 51, an electromagnetic rotary drive unit that rotates the rotor 51 around the axial direction A. The stator 100 is preferably designed for non-contact magnetic levitation of the rotor 51 according to the principle of a bearingless motor. For this purpose, the stator 100 is designed as a bearing and drive stator, by which the rotor 51 can be magnetically driven without contact for rotation around the axial direction A, and can be magnetically levitated without contact with respect to the stator 100. The rotor 51 is passively magnetically stabilized with respect to the axial direction A and actively magnetically levitated in a radial plane perpendicular to the axial direction A, and this radial plane is indicated by line E in FIGS. 1a and 1b.

[0043] The term "bearingless motor" refers to an electromagnetic rotary drive unit in which the rotor 51 can be completely magnetically levitated with respect to the stator 100 and no separate magnetic bearings are provided. For this reason, the stator 100 is designed as both a bearing and a drive stator, being the electrical drive stator 100 and also the magnetic levitation stator 100. The electrical windings of the stator 100 can generate a rotating magnetic field which, on the one hand, applies torque to the rotor 51, causing the rotor to rotate about a desired axis of rotation defined by the axial direction A, and on the other hand, applies an arbitrarily adjustable lateral force to the rotor 51 such that its radial position within the radial plane E can be actively controlled or adjusted. Thus, the three degrees of freedom of the rotor 51, namely the rotation of the rotor and the radial position of the rotor (two degrees of freedom), can be actively adjusted. With regard to a further three degrees of freedom, namely the position of the rotor in the axial direction A and the inclination (two degrees of freedom) with respect to the radial plane E perpendicular to the desired axis of rotation, the rotor 51 is passively magnetically levitated or magnetically stabilized by magnetic resistance, i.e. it cannot be controlled. The complete magnetic levitation of the rotor 51 without separate magnetic bearings is characteristic, which is why the bearingless motor is so named. In the bearing and drive stator 100, the bearing function cannot be separated from the drive function.

[0044] Preferably, the electromagnetic rotary drive unit having the stator 100 and the rotor 51 is designed as a so-called temple motor. The stator 100 has a plurality of coil cores 125, here eight coil cores 125, each of these coil cores having a longitudinal leg 126 extending in the axial direction A from a first end, the lower end according to the depiction in FIGS. 1a and 1b, to a second end, and a transverse leg 127 arranged in the radial plane E at the second end of the longitudinal leg 126. Each transverse leg 127 extends radially from the associated longitudinal leg 126 towards the rotor 51 or the cup-shaped recess 121 respectively and is bounded by the radially inner end face. The coil cores 126 are arranged around the cup-shaped recess 121 in the circumferential direction such that the rotor 51 is arranged between the radially inner end faces of the transverse legs 127 of the coil cores 126.

[0045] All the first ends of the longitudinal legs 126 are connected to each other by a rear iron 122 that conducts magnetic flux. At least one concentrated winding 160, 161 surrounding each longitudinal leg 126 is provided on each longitudinal leg 126. Many variations are known regarding the number and arrangement of the concentrated windings 160, 161, and they will not be described in more detail here. For example, there is such a winding 160 that is wound around exactly one longitudinal leg 126, and such a winding 161 that is arranged around exactly two longitudinal legs 126.

[0046] The temple motor is so named because of a plurality of longitudinal legs 126 that extend in the axial direction A and evoke the columns of a temple.

[0047] In the variant shown in Figure 1b, the stator 100 has a centrally arranged opening 103 that extends axially A from the second axial end 102 of the stator 100 into the cup-shaped recess 121. The centrally arranged opening 103 is designed in a cylindrical manner and penetrates the bottom of the cup-shaped recess 121. Thus, the centrally arranged recess 121 extends axially A through the entire stator 100 from the first axial end 101 to the second axial end 102. In the radial direction, the centrally arranged opening 103 is defined by an inner wall 104. Preferably, the inner wall 104 is designed as a hermetic sealing wall 104 so that components arranged within the stator 100, such as the coil core 125 where the concentrated windings 160, 161 are arranged, are hermetically sealed.

[0048] In the embodiment shown in Figure 1a, there is no centrally arranged opening 103.

[0049] The pump unit 50 has a pump housing 52 with an inlet 523 and an outlet 524 for a fluid, and a rotor 51 disposed within the pump housing 52 for conveying the fluid, the rotor 51 being capable of rotating about the axial direction A. The rotor 51 has a magnetically effective core 511, and the magnetically effective core 511 magnetically interacts with the stator 100 to form torque and generate a magnetic levitation force. For example, the magnetically effective core 511 is a permanent magnet ring or a permanent magnet disk.

[0050] The pump housing 52 is preferably made of a synthetic material, such as polypropylene (PP), polyethylene (PE), polytetrafluoroethylene (PTFE), or perfluoroalkoxy polymer. Of course, embodiments in which the pump housing 52 is made of a metallic material, such as stainless steel, are also possible.

[0051] In particular, the pump unit 50 can also be designed for disposable use, i.e., as a disposable part. The term "disposable part" and other constructs having components that are "disposable", such as disposable components, disposable devices, etc., refer to those devices, components, or parts that are designed for disposable use, i.e., can be used only once as intended and then disposed of. Thus, for a new application, a new, previously unused disposable part must be used. When the pump unit 50 is configured or designed as a disposable device, it is a substantial aspect that the pump unit can be assembled with the reusable stator 100 or can be separated from the stator 100 as easily as possible. Thus, the pump unit 50 should be very easily replaceable without the need for a high assembly effort.

[0052] It is also possible to have such embodiments where the magnetically effective core 511 is non-permanent magnetic, i.e., designed without permanent magnets. In that case, the rotor 51 is designed, for example, as a reluctance rotor. Thus, the magnetically effective core 511 of the rotor 51 is made of, for example, a soft magnetic material. Suitable soft magnetic materials for the magnetically effective core 511 are, for example, ferromagnetic materials or ferrimagnetic materials, i.e., in particular iron, nickel iron, cobalt iron, silicon iron, mu-metal.

[0053] Furthermore, embodiments are possible where the magnetically effective core 511 of the rotor 51 has both ferromagnetic materials and permanent magnetic materials. For example, permanent magnets can be arranged or inserted into the ferromagnetic base body. Such embodiments are advantageous, for example, when it is desired to reduce the cost of a large rotor by saving permanent magnetic materials.

[0054] Typically, the magnetically effective core 511 is completely encapsulated by a plastic material. In other embodiments, the magnetically effective core 511 is completely enclosed in a sheath made of a ceramic material or a metallic material, such as stainless steel or titanium or tantalum.

[0055] Furthermore, the rotor 51 has a plurality of vanes 513 for conveying fluid from the inlet 523 to the outlet 524. The vanes 513 are arranged in a plastic sheath or in the sheath of the magnetically effective core 511. The vanes 513 are preferably made of a plastic material and can be designed, for example, as an integral part of the plastic sheath. Of course, it is also possible to manufacture the individual vanes 513 or the entire vanes 513 in a separate manufacturing process and then connect those vanes to the plastic sheath of the magnetically effective coil 511, for example, by a welding process.

[0056] The impeller formed by the rotor 51 having the vanes 513 is preferably designed as a radial impeller, and the radial impeller receives the fluid entering axially in the direction A from the inlet 523 and then deflects the fluid radially.

[0057] The pump housing 52 has a bottom 521 and a cover 522 closing the bottom 521. The bottom 521 of the pump housing 52 has a cup 531 for receiving the rotor 51. The cup 531 is inserted into a cup-shaped recess 121 in the stator 100 such that the rotor 51, more precisely the magnetic effective core 511 of the rotor 51, is arranged between the lateral legs 127 of the coil core 125.

[0058] For example, the pump unit 50 is attached to the stator housing 120 by a plurality of screws 111. In other embodiments, the pump unit 50 is fixed to the stator 100 by a bayonet connection. In particular, in embodiments of the pump unit 50 as a disposable part, the bayonet connection enables rapid replacement of the pump unit 50. Usually, the bayonet connection is secured by a pin lock.

[0059] In particular, when the centrifugal pump 200 is designed for a very high output, for example an output of 4 kilowatts or more, very large or very strong magnets, for example permanent magnets, are used for the rotor 51 and / or the stator 100. Thereby, a very large magnetic force is generated, so that it becomes very difficult to replace the pump unit 50. When replacing the pump unit 50, there is a significant risk of injury to the operator or damage to the pump unit 50 or the stator 100.

[0060] When the rotor 51 is passively magnetically levitated in the axial direction A, the passive magnetic force typically acts between the rotor 51 and the stator 100 when the stator 100 is de-energized, i.e., when no current is applied to the windings 160, 161 of the stator 100, and these passive magnetic forces have to be overcome in order to replace the pump unit 50.

[0061] Accordingly, according to the present invention, an apparatus for replacing the pump unit 50 of the centrifugal pump 200 is provided. This apparatus is generally denoted by reference numeral 1.

[0062] FIG. 3 shows an exploded perspective view of a first embodiment of the apparatus 1 for replacing the pump unit 50 of the centrifugal pump 200. The depiction in FIG. 3 is a partial cross-section. FIG. 4 shows a perspective view of the first embodiment of the apparatus 1 when the apparatus 1 is fixed to the centrifugal pump 200. In a setting similar to FIG. 4, FIG. 5 shows the apparatus 1 when replacing the pump unit 50.

[0063] The apparatus 1 has an operating device 6 that can apply a mechanical force to the pump unit 50. This mechanical force acts in the axial direction A and is directed to axially separate the pump unit 50 from the stator 100. The apparatus 1 can be fixed to the stator 100.

[0064] In the first embodiment, the operating device 6 preferably has a piston 61 designed in a cylindrical manner, a fixed plate 62, and a crank 64 designed as a threaded crank having a threaded rod 641. The piston 61 is connected to the threaded rod 641 so as to withstand torque. For example, the piston 61 and the threaded rod 641 can also be designed as an integral part. The fixed plate 62 is provided with an internal thread designed to interact with the threaded rod 641. The piston 61 is disposed on one side of the fixed plate 62, and the threaded rod 641 protrudes from the other side of the fixed plate 62, so that by turning the crank 64, the piston 61 can be linearly displaced relative to the fixed plate 62.

[0065] As can be seen particularly in FIG. 3, the stator 100 has a centrally disposed opening 103 that extends axially in the axial direction A from the second axial end 102 of the stator 100 into the cup-shaped recess 121. The centrally disposed opening 103 is designed in a cylindrical manner and is dimensioned such that the piston 61 can be inserted into the centrally disposed opening 103 and the piston 61 can be axially moved back and forth within the opening 103.

[0066] The piston 61 is inserted into the centrally arranged opening 103 from the second axial end 102 of the stator 200. Thereafter, the fixing plate 62 is attached to the second axial end 102 of the stator by a plurality of screws 65 so that the fixing plate 62 is fixed to the stator 100. Next, by operating the crank 64, the piston 61 can be moved back and forth in the axial direction A within the centrally arranged opening 103.

[0067] Next, by displacing the piston 61 in the direction of the first axial end 101 of the stator 100, a mechanical force can be generated to push the pump unit 50 out of the stator 100 (see FIG. 5).

[0068] In the centrifugal pump 200 shown in FIGS. 4 and 5, the stator 100 has a receiving can 105, in which a cup-shaped recess 121 is arranged and into which the pump unit 50 can be inserted. The receiving can 105 forms the first axial end 101 of the stator 100. The receiving can 105 is firmly connected to the stator housing 120, for example, by a form-locking connection and / or by an elastic seal. Of course, the receiving can 105 can also be attached to the stator housing 120 by screws.

[0069] The pump unit 50 has an attachment ring 55, which extends around the cup 531 of the pump housing 52 and is firmly connected to the pump housing 52. The attachment ring 55 serves, for example, by means of screws 551, to attach the pump unit 50 to the stator 100.

[0070] In the embodiment shown in FIGS. 4 and 5, the pump unit 50 is pushed out of the stator 100 in the axial direction A to replace the pump unit 50, i.e., a mechanical force is applied to the cup 531, whereby the cup 531 and thus the entire pump unit 50 are pushed out of the stator 100.

[0071] FIG. 4 shows a centrifugal pump 200 in an operational ready state, where the pump unit 50 is disposed within the cup-shaped recess 121 of the stator 100. It can be clearly seen in FIG. 4 that the threaded rod 641 projects from the second axial end 102 of the stator 100. Here, for example, if the pump unit 50 is to be separated from the stator 100 for reasons such as the need to replace the pump unit 50 with a new one, the crank 64 is actuated to displace the piston 61 within the centrally disposed opening 103 in the direction of the first axial end 101 of the stator 100. Since the centrally disposed opening 103 extends into the cup-shaped recess 121, a passage is provided at the bottom of the cup-shaped recess 121, so that the piston 61 can move through the bottom of the cup-shaped recess 121 and then directly abut against the cup 531 of the pump housing 52 of the pump unit 50. As soon as the piston 61 abuts against the cup 531 of the pump housing 52, further actuation of the crank 64 causes the pump unit 50 to be pushed out of the stator 100. FIG. 5 shows the centrifugal pump 200 with the pump unit 50 in an end position where it has been completely pushed out of the stator 100. At this position, since only a very weak magnetic force, if any, still acts between the rotor 51 and the stator 100, the pump unit 50 can be removed or replaced very easily. In FIG. 5, it can also be seen that the threaded rod 641 has moved considerably into the stator 100 at this point.

[0072] Optionally, the device 1 for replacing the pump unit 50 has a guide rail 66 which can be firmly fixed to the stator 100 or is firmly fixed to the stator 100 and extends axially A away from the stator 100 from the first end 101 of the stator 100. A support element 67 is arranged on this guide rail 66, and this support element 67 is supported on the guide rail 66 and can move back and forth axially A on the guide rail 66. The support element 67 is designed to support the pump unit 50 when the pump unit 50 is pushed out of the stator 100. For example, the support element 67 can partially surround the pump unit 50 so that the pump unit 50 is accurately pushed out of the stator 100 axially A. By doing so, the pump unit 50 can be effectively prevented from being distorted or tilted by a strong magnetic force, especially when it is pushed out of the stator 100.

[0073] Of course, embodiments are also possible in which the movement of the piston 61 within the centrally arranged opening 103 is performed by a motor. For this purpose, for example, a spindle motor for moving the piston 61 within the centrally arranged opening 103 can be provided instead of the crank 64.

[0074] The device 1 can be permanently attached to the centrifugal pump 200 or the stator 100, for example, also during the operation of the centrifugal pump 200.

[0075] Alternatively, only when necessary, that is, for replacing the pump unit 50, the device 1 can be fixed to the stator 100 and removed from the stator 100 again after the pump unit 50 has been replaced. Furthermore, some components of the device 1 can be permanently fixed to the stator 100, while on the other hand, other components of the device 1 can be fixed to the stator 100 only for replacing the pump unit.

[0076] FIG. 6 shows an exploded perspective view of a second embodiment of the apparatus 1 according to the invention for replacing the pump unit 50, the depiction being a partial cross-section. For better understanding, FIG. 7 also shows a perspective view of the second embodiment, which is fixed to the centrifugal pump 200.

[0077] In the following, only the differences from the first embodiment will be described. Parts that are the same or parts of the second embodiment with equivalent functions are denoted using the same reference numerals as in the first embodiment. In particular, the reference numerals have the same meaning as already explained in connection with the first embodiment. It is understood that all previous descriptions of the first embodiment apply equally or similarly to the second embodiment as well.

[0078] In the second embodiment, the actuating device 6 is designed such that mechanical force acts on a region of the pump housing 52 that is arranged outside the cup-shaped recess 121 of the stator 100. In the second embodiment, since the mechanical force does not act directly on the cup-shaped recess 121 or on the cup 531 of the pump housing 52, the second embodiment also does not require a centrally arranged opening 103 within the stator 100.

[0079] In the second embodiment, the actuating device 6 has a mounting device 70 that can be fixed to the first axial end 101 of the stator 100, for example by means of a plurality of fixing screws 75. The mounting device 70 has a ring-shaped base 71, which is designed such that it can surround the pump housing 52, in particular the cup 531 of the pump housing 52. The ring-shaped base 71 is attached to the first axial end 101 of the stator 100 by means of the fixing screws 75 such that the ring-shaped base 71 is arranged around the cup-shaped recess 121. Thus, the cup 531 of the pump housing 52 can be inserted into or removed from the cup-shaped recess 121 via the ring-shaped base 71.

[0080] Several, here four guide elements 72 are provided on the ring-shaped base 71, each of which extends away from the stator 100 in the axial direction A from the ring-shaped base 71. Each guide element 72 is designed here in a rod shape. The guide elements 72 are arranged such that the pump housing 52 of the pump unit 50 is guided in the axial direction A between the guide elements 72. Optionally, a groove 74 extending in the axial direction A in each case for each guide element 72 can be provided in the pump housing 52, and each respective guide element 72 engages in this groove. By doing so, the twisting of the pump housing 52 with respect to the mounting device 70 can be effectively avoided.

[0081] Furthermore, several attachment elements 77 are provided on the pump housing 52, and by means of these attachment elements 77, the pump housing 52 can be fixed to the mounting device 70. The attachment elements 77 are designed, for example, as fixing screws 77 and are arranged on the pump housing 52. For each fixing screw 77, a female-threaded part 78 is provided on the ring-shaped base 71 in each case, and each respective fixing screw 77 engages in this female-threaded part 78. In this way, the pump unit 50 can be securely attached to the mounting device 70.

[0082] The mounting device 70 has several elastic elements 79, and these elastic elements 79 are arranged such that when the pump unit 50 is fixed to the stator 100, a tension is applied in the axial direction A. This means that when the pump unit 50 is inserted into the cup-shaped recess 121 and tightened by the fixing screws 77, the elastic elements 79 are tensioned. Thus, the pump unit 50 is inserted into the cup-shaped recess 121 against the elastic force of the elastic elements 79. FIG. 7 shows the inserted state of the pump unit.

[0083] Next, when the pump unit 50 is to be replaced, the fixing screws 77 are loosened, and the tensioned elastic elements 79 push the pump unit 50 in the axial direction A away from the stator 100 by their elastic force.

[0084] Figure 6 shows possible designs and arrangements of the elastic element 79. Each of the guide elements 72 has an axial groove 721 extending in the axial direction A on its radially inner side. A hinge spring such as the elastic element 79 is disposed within each axial groove 721. Next, when the pump unit 50 is inserted into the cup-shaped recess 121 via the mounting device 70 and fixed by the fixing screw 77, the hinge spring is tensioned within the axial groove 721.

[0085] When the fixing screw 77 is loosened to replace the pump unit 50, the pump unit 50 is pushed out of the stator along the guide element 72 by the spring force of the hinge spring acting in the axial direction A.

[0086] Of course, many other variations of the specific embodiments are possible. The insertion of the pump unit 50 into the stator 100 is preferably against the force of these elastic elements 79, such that when the pump unit 50 is fixed within the stator 100, these elastic elements 79 are tensioned in the axial direction A. This is a substantial aspect of the second embodiment.

[0087] For example, an axial spring can also be provided between the pump housing 52 and the mounting device 70.

[0088] Figure 8 shows a perspective view of a third embodiment of the device for replacing the pump unit 50 of the centrifugal pump 200, with the pump unit 50 separated from the stator. Figure 9 shows the third embodiment after the first stage of inserting the pump unit 50 into the stator 100. Figure 10 shows the third embodiment after the completion of inserting the pump unit 50 into the stator 100.

[0089] In the following, only the differences from the first and second embodiments will be described. Parts that are the same or parts having equivalent functions in the third embodiment are denoted by the same reference numerals as in the first and second embodiments. In particular, the reference numerals have the same meaning as already described in relation to the first and second embodiments. It is understood that all of the previous descriptions of the first and second embodiments apply equally or similarly to the third embodiment as well.

[0090] In the third embodiment, the removal of the pump unit 50 from the stator 100 and the insertion of the pump unit 50 into the stator 100 are performed by a lever action.

[0091] In FIG. 8, the pump unit 50 is shown separated from the stator 100. In the third embodiment, the operating device 6 of the apparatus 1 has a mounting ring 80 that can be fixed to the first axial end 101 of the stator 100, for example, by a plurality of screws 801. The mounting ring 80 is designed to be able to surround the pump housing 52, particularly the cup 531 of the pump housing 52. The mounting ring 80 is attached to the first end 101 of the stator 100 by the screws 801 such that the mounting ring 80 is disposed around the cup-shaped recess 121. Accordingly, the cup 531 of the pump housing 52 can be inserted into or removed from the cup-shaped recess 121 via the mounting ring 80.

[0092] A first guide rod 81 and a second guide rod 82, each extending axially A away from the stator 100 from the mounting ring 80, are arranged on the mounting ring 80. Preferably, the two guide rods 81, 82 are arranged diametrically opposed. A pivotable holding device 83 for holding the pump unit 50 is provided on the first guide rod 81. The holding device 83 can pivot about the first guide rod 81. For this purpose, the holding device 83 has, for example, a first guide pin 831 which engages with the first guide rod 81 and is rotatable within the first guide rod 81. Furthermore, the first guide pin 831 can be displaced axially A within the first guide rod 81.

[0093] The holding device 83 further has a second guide pin 832 (FIG. 9), which is preferably arranged diametrically opposed to the first guide pin 831. Furthermore, in each case a tension lever 85 is provided on the holding device 83 for each of the guide pins 831, 832, and this tension lever 85 can be moved up and down between an open position (FIG. 9) and a closed position (FIG. 10).

[0094] FIG. 8 shows the holding device 83 in a first position. From this first position, the holding device 83 can pivot preferably 180° about the first guide rod 81 to reach a holding position. The holding position is shown in FIG. 9. In the holding position, the holding device 83 abuts against the second guide rod 82. Next, the second guide pin 832 is aligned with the second guide rod 82 so that the second guide pin 832 can engage with the second guide rod 82 when the holding device 83 is displaced axially A. This can be seen particularly in FIG. 9.

[0095] The holding device 83 further has a holding opening 833, which is designed to be able to surround the pump housing 52 of the pump unit 50. The holding opening 833 is open on one side so that the holding device 83 can pivot over the pump unit 5 with the pump housing 52 being arranged in the holding opening 833 of the holding device 83. The pump housing 52 and the holding opening 833 are designed such that when the pump housing 52 is arranged in the holding opening 833, the pump housing 52 can no longer be displaced axially A relative to the holding device 83.

[0096] Preferably, a removable protective jacket 87 is provided on the pump housing 52, and this protective jacket 87 surrounds the cup 531 of the pump housing 52 in a ring shape. The protective jacket 87 has an outer diameter larger than the inner diameter of the cup-shaped recess 121, so that the pump unit 50 cannot be inadvertently drawn into the cup-shaped recess 121. The protective jacket 87 is preferably designed to have two parts, for example two half-shells (FIG. 9), so that the protective jacket 87 can be easily removed from the cup 531 of the pump housing 52.

[0097] The protective cup 87 not only prevents the pump unit 50 from being damaged by being forcedly pushed into the stator 100 by strengthening the strong magnetic force to draw the pump unit 52 into the stator 100, but also, in particular, for the rotor 51 designed in a permanent magnet type, prevents the cup 531 from being protected from the attraction of ferromagnetic materials.

[0098] It is understood that the protective cup 87 can also be provided in other embodiments of the device 1 according to the present invention.

[0099] Hereinafter, the insertion of the pump unit 50 into the stator 100 will be described with reference to FIGS. 8 to 10. First, the holding device 83 is brought to the first position shown in FIG. 8. The pump unit 50 having the protection cup 87 is placed on the mounting ring 80 and brought into contact with the first end 101 of the stator 100.

[0100] Next, the holding device 83 is brought to the holding position shown in FIG. 10, that is, the holding device 83 is pivoted about the first guide rod 81 and pivoted onto the pump unit 50 so that the pump unit 50 is held in the holding opening 833 of the holding device 83. Next, the protection cup 87 is removed. By operating the tension lever 85, that is, by tilting the tension lever 85 downward by 180° (in accordance with the depiction in FIG. 9), the pump unit 50 is pushed into the cup-shaped recess in the stator 100 in the axial direction A.

[0101] To separate the pump unit 50 from the stator 100, the pump unit 50 is pushed out of the cup-shaped recess 121 in the axial direction A by moving the tension lever 85 from the closed position (FIG. 10) to the open position (FIG. 9).

[0102] Thereafter, the holding device 83 is pivoted to the first position (FIG. 8), and the pump unit 50 can be removed.

[0103] Preferably, a locking element 88 is provided on the second guide rod 82, and when the pump housing 52 is disposed in the cup-shaped recess 121, the locking element 88 can fix the holding device 83 to the first guide rod 81. The locking element 88 is designed, for example, as a locking pin having a snap-in function, and when the pump housing 52 is disposed in the cup-shaped recess 121, this locking pin engages with a hole in the second guide pin 832.

[0104] A modification of the third embodiment is shown in FIGS. 11 and 12. FIG. 11 shows an exploded perspective view of the modification of the third embodiment, and FIG. 12 shows a perspective view of the modification. The pump unit 50 is shown separated from the stator 100 in the same manner as in FIG. 8.

[0105] The modifications described below are also possible for other embodiments, for example, for the second embodiment in the same manner. The modification will be described here as an example for the third embodiment.

[0106] In the modification shown in FIGS. 11 and 12, the stator 100 has an opening 103 disposed at the center, and the opening 103 disposed at the center extends axially A into the cup-shaped recess 121 from the second axial end 102 of the stator 100 in the same manner as described in connection with FIG. 3. The opening 103 disposed at the center is designed in a cylindrical manner. In this modification, the actuating device 6 has a spring element 60, and the spring element 60 is disposed within the opening 103 disposed at the center. The spring element 60 is designed such that when the pump unit 50 is inserted into the cup-shaped recess 121, the spring element 60 is tensioned axially A. Thus, when the pump unit 50 is inserted, the spring element 60 has a damping effect. When the pump unit 50 is separated from the stator 100, the spring element 60 facilitates the removal of the pump unit 50 from the cup-shaped recess 121 by the spring force acting axially A.

[0107] For example, the spring element 60 is designed as a gas spring. As can be seen particularly in FIG. 11, the spring element 60 has a cylinder 602, and within this cylinder 602, a plunger 603 that can move in the axial direction A is arranged. A plate 601 is arranged at the end of the plunger 603, and this plate 601 is arranged outside the cylinder 602 and positioned within the cup-shaped recess 121. In the bottom of the cup-shaped recess 121, a passage through which the plunger 603 extends is provided. When the pump unit 50 is inserted into the cup-shaped recess 121, the plate 601 and the plunger 603 are displaced in the direction of the cylinder 602, whereby the gas volume within the cylinder 602 is compressed in a manner known per se. This compression results in a spring force, and this spring force is directed in the axial direction A so as to displace the plate 601 in the direction of the first axial end 101 of the stator 100.

[0108] A base element 604 is provided at the second axial end 102 of the stator 100, and this base element 604 is fixed to the stator 100 and engages with the centrally arranged opening 103. The spring element 60 is supported by this fixed base element 604.

[0109] In the following, a fourth embodiment of the device 1 for replacing the pump unit 50 will be described with reference to FIGS. 13 to 17. FIG. 13 shows a perspective view of the fourth embodiment of the device 1. The pump unit 50 is not shown in FIG. 13. In the perspective view, FIGS. 14 to 17 each show the fourth embodiment at various stages of inserting the pump unit 50 into the stator 100.

[0110] In the following, only the differences from the first, second, and third embodiments will be described. The same parts or parts with equivalent functions in the fourth embodiment are denoted by the same reference numerals as those used in the previously described embodiments. In particular, the reference numerals have the same meaning as those already described in relation to the first, second, and third embodiments. It is understood that all of the previous descriptions of the first, second, and third embodiments apply equally or similarly to the fourth embodiment as well.

[0111] In a fourth embodiment of the device 1 according to the invention, the pump unit 50 is fixed in the stator 100 by a bayonet connection. For this purpose, the device 1 has a bayonet ring 90, which can be fixed to the first axial end 101 of the stator 100 such that the bayonet ring 90 is arranged around the cup-shaped recess 121. The bayonet ring 90 is designed for a bayonet connection to the pump housing 52 of the pump unit 50. For this purpose, the bayonet ring 90 has a plurality of claw portions 91, which are designed to interact with projections 92 (FIG. 14), and the projections 92 are arranged on the outside of the pump housing 52. Furthermore, a plurality of receiving grooves 93 are provided on the radially inner surface of the bayonet ring 90, and by means of these receiving grooves 93, a bayonet connection can be formed and released between the pump housing 50 and the bayonet ring 90.

[0112] The bayonet ring 90 is attached to the first axial end 101 of the stator by a plurality of fixing screws 94 such that the bayonet ring 90 is firmly connected to the stator 100.

[0113] Particularly preferably, the bayonet ring 90 is designed such that the pump housing can be fixed within the bayonet ring 90 by a rotational movement of the pump housing relative to the bayonet ring 90 about the axial direction A, a subsequent movement in the axial direction A, and a subsequent rotational movement about the axial direction A. The two rotational movements occur in the same direction. Accordingly, the receiving groove 93 in the bayonet ring 90 is designed accordingly. This can be best seen in FIG. 13. After inserting the pump housing into the receiving groove 93, the pump housing 52 must first be rotated relative to the bayonet ring 90 about the axial direction A, and then the pump housing 52 can be moved in the receiving groove 93 in the axial direction A towards the stator 100. After completing this linear movement, the pump housing 52 must be rotated again relative to the bayonet ring 90 about the axial direction A such that the claw portion 91 of the bayonet ring 90 engages with the projection 92 on the pump housing 52, thereby fixing the pump unit 50 to the bayonet ring 90. The release of the pump unit 50 occurs in the reverse order.

[0114] Preferably, a securing ring pin 95 is also provided on the bayonet ring 90, and this securing ring pin engages in a recess in the pump housing 52 as soon as the pump housing 52 is fixed to the bayonet ring 90. The securing ring pin 95 has a snap-in function known per se, i.e., the securing ring pin 95 automatically engages in a recess in the pump housing 52 as soon as the pump housing 52 reaches the position where it is fixed to the bayonet ring 90. To separate the pump unit 50 from the stator again, the securing ring pin 95 must first be manually pulled out of the recess in the pump housing 50, and then the bayonet connection can be released. Accordingly, the securing ring pin 95 prevents unintentional separation of the pump unit 50 from the stator 100.

[0115] The formation of the bayonet connection between the pump unit 50 and the stator 100 will be described with reference to FIGS. 14 to 17. First, the pump unit is inserted axially A into the bayonet ring 90 so as to achieve the position shown in FIG. 14. Next, the pump unit 50 is rotated clockwise about the axial direction A as depicted in FIGS. 14 and 15 until the pump housing 50 abuts against the nose 931 that defines the receiving groove 93. This state is shown in FIG. 15. Thereafter, the pump unit 50 is moved axially A towards the first axial end 101 of the stator 100. After this movement in the axial direction A, the pump unit 50 comes to the position shown in FIG. 16. Then, the pump unit 50 is rotated clockwise about the axial direction A as depicted in FIGS. 16 and 17. By this rotational movement, the claw portion 91 of the bayonet ring 90 comes into engagement with the projection 92 in the pump housing 52, the nose 931 surrounds the outlet 524 of the pump housing 52, and the securing ring pin 95 engages with the recess in the pump housing 52. This state is shown in FIG. 17. In this position, the pump unit 50 is fixed to the bayonet ring 90 and is protected from unintentional release.

[0116] In the fourth embodiment, the actuating device 6 is designed in the same way as a modification of the third embodiment described with reference to FIGS. 11 and 12. Accordingly, the actuating device 6 has a spring element 60, and this spring element 60 is arranged within an opening 103 arranged at the center of the stator 100.

[0117] The spring element 60 is designed such that when the pump unit 50 is inserted into the cup-shaped recess, the spring element 60 is tensioned in the axial direction A. Accordingly, the spring element 60 has a damping effect when the pump unit 50 is inserted. When the pump unit 50 is separated from the stator 100, the spring element 60 causes (or at least facilitates) the removal of the pump unit 50 from the cup-shaped recess 121 by the spring force acting in the axial direction A.

[0118] The spring element 60 is designed, for example, as a gas spring and has a cylinder 602 in which a plunger 603 that can move in the axial direction A is arranged. At the end of the plunger 603, a plate 601 positioned within the cup-shaped recess 121 is arranged, and this plate 601 is arranged outside the cylinder 602. In the cup-shaped recess 121, a passage through which the plunger 603 extends is provided at its bottom. When the pump unit is inserted into the cup-shaped recess 121, the plate 601 and the plunger 603 are displaced in the direction of the cylinder 602, whereby the gas volume within the cylinder 602 is compressed in a manner known per se. This compression results in a spring force that is directed in the axial direction A so as to displace the plate 601 in the direction of the first axial end 101 of the stator 100. A base element 604 is provided at the second axial end 102 of the stator 100, and this base element 604 is fixed to the stator 100 and engages with the centrally arranged opening 103. The spring element 60 is supported by this fixed base element 604.

Claims

1. A device for replacing a pump unit (50) of a centrifugal pump (200), the centrifugal pump (200) having the pump unit (50) and a stator (100) extending in an axial direction (A) from a first axial end (101) to a second axial end (102), the first axial end (101) being provided with a cup-shaped recess (121) into which the pump unit (50) can be inserted, the pump unit (50) being inserted into the cup-shaped recess (121) of the stator (100).

1. A device having a pump housing (52) with a cup (531) into which a fluid can be inserted, a rotor (51) for conveying a fluid is arranged in said pump housing (52), said rotor having a magnetically active core (511), said rotor (51) can be rotated about said axial direction (A), said stator (100) is designed for contactless magnetic driving and contactless magnetic levitation of said rotor (51), said rotor (51) being passively magnetically stabilized with respect to said stator at least in the axial direction (A), The device comprises an actuator (6) capable of applying a mechanical force to the pump unit (50), the mechanical force acting in the axial direction (A) and directed so as to separate the pump unit (50) from the stator (100) in the axial direction (A).

2. 2. The device according to claim 1, wherein the actuating device (6) is designed such that the mechanical force acts on the cup-shaped recess (121) in the stator (100) or on the cup (531) of the pump housing.

3. 3. The apparatus according to claim 1 or 2, wherein the actuation device (6) has a piston (61) displaceable in an axial direction (A), the piston (61) being insertable into an opening (103) centrally disposed in the stator (100), and wherein displacement of the piston (61) relative to the stator (100) generates the mechanical force that separates the pump unit (50) from the stator (100) in the axial direction (a).

4. 4. The device according to claim 1, further comprising a guide rail (66) which can be fixed to the stator (100), and a support element (67) displaceable in the axial direction (A) is arranged on the guide rail (66), the support element preventing the pump unit (50) from tilting when the pump unit (50) is separated from the stator (100).

5. 5. The device according to claim 1, wherein the actuating device (6) is designed such that the mechanical force acts on an area of ​​the pump housing (52) that is located outside the cup-shaped recess (121) of the stator (100).

6. 6. The device according to claim 1, wherein the actuation device (6) comprises a spring element (60) that can be inserted into a centrally located opening (103) in the stator (100), the spring element (60) being designed to be tensioned in the axial direction (A) when the pump unit (50) is inserted into the cup-shaped recess (121).

7. 7. The device according to claim 1, further comprising a mounting device (70) which can be fixed to the first axial end (101) of the stator (100), the mounting device (70) having a ring-shaped base (71) designed to surround the pump housing (52), several guide elements (72) arranged on the base (71) for guiding the pump housing (50) in the axial direction (A) into the cup-shaped recess (121) of the stator (100), several attachment elements (75) are provided for fixing the pump housing (52), the mounting device (70) having several elastic elements (79) which are tensioned in the axial direction (A) when the pump unit (50) is fixed in the stator (100).

8. 7. The device according to claim 1, further comprising a mounting ring (80) which can be fixed to the first axial end (101) of the stator (100) so as to be arranged around the cup-shaped recess (121), a first guide rod (81) and a second guide rod (82) each extending in an axial direction (A) are arranged on the mounting ring (80), the first guide rod (81) is provided with a pivotable holding device (83) for holding the pump unit (5), the holding device (83) can be pivoted to a holding position in which the holding device (83) abuts the second guide rod (82), and at least one tension lever (85) is provided, by actuation of which the holding device (83) can be displaced in the axial direction (A) along the guide rods (81, 82).

9. 9. The apparatus according to claim 8, wherein one of the guide rods (82) is provided with a locking element (88) by which the retaining device (83) can be fixed to the guide rod (82) when the pump housing (52) is placed in the cup-shaped recess (121).

10. 7. The device according to claim 1, further comprising a bayonet ring (90) capable of being fixed to the first axial end (101) of the stator (100) such that the bayonet ring (90) is arranged around the cup-shaped recess (121), the bayonet ring (90) being designed for a bayonet connection to the pump housing (52) of the pump unit (50).

11. 11. The apparatus of claim 10, wherein the bayonet ring (90) is designed such that the pump housing (52) can be fixed within the bayonet ring (90) by a rotational movement relative to the bayonet ring (90) about the axial direction (A), a subsequent axial movement (A), and a subsequent rotational movement about the axial direction (A).

12. 12. Apparatus according to claim 10 or 11, wherein the bayonet ring (90) is provided with a securing pin (95) by means of which the pump unit (50) can be secured within the bayonet ring (90) when the pump housing (52) is placed in the cup-shaped recess (121).

13. A centrifugal pump for conveying a fluid, comprising a pump unit (50) and a stator (100) extending in an axial direction (A) from a first axial end (101) to a second axial end (102), the first axial end (101) being provided with a cup-shaped recess (121) into which the pump unit (50) can be inserted, the pump unit (50) comprising a cup (531) that can be inserted into the cup-shaped recess (121) of the stator (100). A centrifugal pump having a pump housing (52), in which a rotor (51) for conveying said fluid is arranged, said rotor having a magnetically active core (511), said rotor (51) forming an electromagnetic rotary drive together with said stator (100), said stator (100) being designed for contactless magnetic driving and contactless magnetic levitation of said rotor (51), said rotor (51) being passively magnetically stabilized at least in the axial direction (A), A centrifugal pump, characterized in that a device for replacing the pump unit (50) is provided, said device being designed according to any one of claims 1 to 12.

14. 14. The centrifugal pump according to claim 13, wherein the device (1) for replacing the pump unit (50) is designed to be removable from the centrifugal pump (100) in each case after the pump unit (50) has been replaced.

15. 15. The centrifugal pump according to claim 13 or 14, wherein the electromagnetic rotary drive is designed as a temple motor, the stator (100) has a number of coil cores (125), each of which has a longitudinal leg (126) extending from a first end in an axial direction (A) to a second end and a transverse leg (127) arranged at the second end of the longitudinal leg (126) and extending in a radial direction perpendicular to the axial direction (A), the coil cores (125) are arranged around the rotor (51) in a circumferential direction such that the rotor (51) is arranged between the transverse legs (127) of the coil cores (125), and each longitudinal leg (126) is provided with at least one concentrated winding (160, 161), the winding surrounding each longitudinal leg (126).

Images