JPH0347870B2 - - Google Patents

Description

Claim 1: For conveying fluid without damaging it,
In particular, in airtightly encapsulated centrifugal pumps for transporting blood, which have a fluid-rotating transport member 9 that moves on a rotating track within the pump chamber. The conveying members 12, 42, 43 fixed to the members 6, 27, 36 are arranged for a central spatially stationary movement relative to the pump chamber 25, and the holding member outside the pump chamber A mechanical connection is formed between the rotating drive members 3, 26 arranged at a sealing member 1 formed by an elastic diaphragm, which has a reduced value with respect to the radius of the orbit of rotation in the region 8 in which it penetrates the wall of the pump chamber;
5, 18 on the one hand in the area of the wall of the pump chamber surrounding the point penetrated by the holding element, and on the other hand of the holding element and/or the conveying element, which are likewise arranged spatially in a fixed position in the pump chamber. A hermetically encapsulated centrifugal pump for the non-damaging conveyance of fluids, characterized in that it is hermetically coupled with a range.

2. The centrifugal pump according to claim 1, wherein the radius of the grinding movement of the holding member in the range 8 has at least a relative minimum value.

3. From the rotating drive members 3, 26 to the holding member 6,
The centrifugal device according to claim 1 or 2, wherein the force is transmitted eccentrically to the holding member 6, 27, and the holding member extends from the drive member in the direction of extension of the rotation axis of the holding members 6, 27. pump.

4. The transmission of force from the rotating drive member to the holding member 36 is concentric, and the grinding movement is caused by bending, tilting or folding the holding member. The centrifugal pump according to item 1 or 2.

5. Bearings 4, 5, 28 are provided between the drive member 3 and the holding or conveying member 6 or 9 for compensating the relative rotational movement.
The centrifugal pump according to any one of Items 1 to 4.

6. Claim 5, in which the bearing is oriented coaxially with an axis specific for the sawing movement, and the holding and/or conveying member is configured approximately rotationally symmetrically with respect to said axis. Centrifugal pump as described in section.

7. The centrifugal pump according to any one of claims 1 to 6, wherein at least the holding member 6 of the conveying member 9 is surrounded by a sealing member 17.

8. Centrifugal pump according to claim 7, in which the conveying member 9 is likewise surrounded by a sealing member 17.

9 The sealing member 15 is the lining 1 of the conveying member 9
7. Flexible sealing diaphragm in the bearing area of the drive member 8, the lining of the pump chamber being designed as a continuously molded diaphragm, which is adapted to the fluid and has a durable structure with respect to alternating bending loads. Centrifugal pump according to any one of claims 1 to 7, consisting of a material.

10 The flexible sealing element consists of a lining in the form of a continuous bag 18, closed except for the inlet and the outlet, into which the conveying element 9 is pushed, the sealing element being held 10. Centrifugal pump according to claim 1, comprising a sealing area 8 between the part and the pump casing.

11. According to any one of claims 1 to 10 for conveying blood, in which the sealing members 15, 18 are made of or coated with a material compatible with blood. Centrifugal pump as described.

12 Endo-implantable pump casing 11,1
6 consisting entirely of or coated with a material compatible with blood, for transporting blood according to any one of claims 1 to 11. centrifugal pump.

13 The material that is suitable for blood is polyurethane.
A centrifugal pump according to claim 12.

14. The pump according to any one of claims 1 to 13, wherein the pump chamber having the rotational orbit of the conveying member 9 is expanded in a hopper-like manner to an area adjacent to the support portion of the drive member. centrifugal pump.

15 Pump casing has inlet 14 and outlet 1
15. Centrifugal pump according to any one of claims 1 to 14, which is divided into an upper part 11 having 3 and a lower part 16 having a penetration for the drive member. .

16 The conveying member 9 is configured as a member rotationally symmetrical with respect to an axis specific to the grinding movement of the holding member, and the part of the casing 11 that forms the gap 19 with the conveying member has the shape of the gap. 16. A centrifugal pump according to claim 1, wherein the pump is configured to be substantially independent of the position of the conveying member on the rotational track.

17. Claim 1, wherein said member is of fully or partially spherical, conical or elliptical configuration.
Centrifugal pump according to item 6.

18. A body according to claims 1 to 17, which is configured as an incompletely rotating body such that its largest cross section is oriented transversely to the conveying element when the conveying element approaches the outlet. Centrifugal pump according to any one item.

19. Claims 1 to 1, wherein the center point 23 of the rotating orbit 22 on which the conveying member 9 moves is shifted from the center 24 of the pump chamber 25.
Centrifugal pump according to any one of items up to item 8.

20 The center point 23 of the rotating orbit 22 is the pump chamber 25
is arranged offset by a second angle with respect to the axis of symmetry perpendicular to the direction of outflow, between the conveying member and the pump chamber and the outflow opening 13 which reach the end on the rotary track 22. 20. A centrifugal pump according to claim 19, wherein a minimum value is provided between the edges of the centrifugal pump.

21 A hollow chamber 29 is provided which receives a bearing device for the drive device 1 of at least the holding element 27, which hollow chamber 29 is separated from the pump chamber by a sealing element and is filled with liquid. 21. A centrifugal pump according to any one of claims 1 to 20.

22. Centrifugal pump according to claim 21, wherein the hollow chamber 29 is penetrated by a fluid serving as a cooling, lubricating and/or driving medium through inlets and outlets 32 and 33 provided in its walls.

23. Centrifugal pump according to claim 22, wherein at least one opening (32 or 33) serves at the same time as a through opening for a cable 34 of an electric motor 1 for driving the conveying member 9.

24. Centrifugal pump according to any one of claims 1 to 23, wherein the drive device 1 of the conveying member 9 and the pump chamber are surrounded by a common casing 31.

25. The inlet 14 is arranged in the pump chamber on the drive side of the conveying member (FIG. 7).
The centrifugal pump according to any one of paragraphs 24 to 24.

26 The holding element 26, the conveying element and/or the drive element of the bearing 3 are mounted inside the casing 31 and are hermetically encapsulated in the pump casing, with the magnetic field 37 rotating outside the pump casing. Centrifuge according to any one of claims 1 to 25, preferably for implantation under the skin and/or tissue layer of a living body, rotated by pump.

27. Claims in which the pump casing 31, together with the encapsulated magnet, is implantable in vivo such that the skin or tissue layer 38 is surrounded by the pump casing 31 and that a rotating magnetic field can be placed from outside the body. The centrifugal pump according to any one of paragraphs 1 to 26.

28. Centrifugal device according to any one of claims 1 to 27, wherein the rotational speed of the pump is periodically controlled in such a way that an at least approximately physiologically pulsating flow is produced. pump.

29 The central axes of the outflow and/or inflow in one plane or three-dimensionally, in particular the position of the inflow and outflow allows for an anatomically favorable connection when used as a blood pump. 29. A centrifugal pump according to any one of claims 1 to 28, which is curved in this manner.

30. Any one of claims 1 to 29, wherein the holding member is arranged in the pump chamber without a separate bearing arrangement, and in the assembled state the bearing function is provided by the motor shaft. Centrifugal pumps as described in Section.

31 Separation points A, B, which can be easily separated between the upper part of the pump and the holding part that holds the motor.
Claims 1 to 3, in which C is provided.
The centrifugal pump according to any one of items up to item 0.

32. The centrifugal pump according to claim 31, wherein the separation point A intersects the pump chamber excluding the conveying member.

33. Centrifugal pump according to claim 31, wherein the separation point B is located outside the pump chamber and intersects the connection line of the conveying member to the motor shaft.

34. The separating point C intersects a connecting element of the motor shaft, which connecting element is constructed in two parts so that the centering element, which is connected to the holding element, can be removed together with the pump chamber. The centrifugal pump according to any one of paragraphs 1 to 33.

35. A centrifugal pump according to claim 34, wherein the centering member has an eccentrically arranged receptacle for receiving the retaining member.

36. The centrifugal pump of claim 35, wherein the centering member is retained by an attachment member.

37 Permanent magnet 6 with at least one attachment member
3,64, and these permanent magnets 63,6
37. Centrifugal pump according to claim 36, in which 4 acts alternately in this range with a centering device suitably ferromagnetically constructed.

38 The centrifugal pumps 69, 70 are configured as twin pumps and are driven by a common drive, which drives the conveying members 42, which are angularly offset relative to each other. 4
38. Centrifugal pump according to any one of claims 1 to 37, wherein the centrifugal pumps 3 and 3 are driven at the same rotational speed.

39. Claim 3, in which both conveying members 42, 43 are arranged dynamically balanced together.
Centrifugal pump according to item 8.

40. Centrifugal pump according to any one of claims 30 to 39, wherein both pumps 69, 70 are connected in series.

41. Claims 1 to 4, preferably used in a mass exchange circuit for dialysis or an oxygenator, in which the mass exchanger is connected at the inlet or outlet with at least one pump 73 or 74. Centrifugal pump according to any one of items up to 40.

42. Claim 4, wherein the inlet or outlet connected to the mass exchanger circumferentially surrounds the pump chamber at least partially in the form of a ring gap.
The centrifugal pump according to item 1.

43. The centrifugal pump of claim 40, wherein the mass exchanger at least partially surrounds the drive motor 68.

44 The conveying member is composed of a plurality of materials or a plurality of materials or a single material and a hollow chamber such that the average density of the conveying member is at least approximately the same as the density of the fluid, and the conveying member includes the holding member. The fluid is dynamically balanced,
Any one of claims 1 to 43
Centrifugal pumps as described in Section 1.

Description The invention relates to a centrifugal pump (rotary pump) of the type defined in the preamble of claim 1 and a method for manufacturing the same.

As is well known, centrifugal pumps are particularly suitable as blood pumps because they transport fluids without damaging them, and they are simpler in construction than diaphragm pumps, have a smaller volume, and are easier to adjust and control. Moreover, it has the advantage of high operational reliability. If a centrifugal pump used as a blood pump is appropriately designed, damage to the transported blood can be kept to a minimum. Blood centrifugal pumps are implanted in vivo to assist or replace the heart. In addition, blood centrifugal pumps are mechanically more expensive and have larger constructional dimensions than centrifugal pumps, and also cause harmful wear (sparation) due to deformation movements of the material.
It is suitable for use in place of the hose pumps often used today in the medical field.

Known centrifugal pumps have a rotating conveying member, a rotor, which is mounted outside the pump chamber.
In this case, the rotor shaft must pass through the pump casing and be sealed against it. An example of this is the sliding ring seal used in the device shown in U.S. Pat. No. 3,864,055. Such sliding ring seals are problematic due to tornado formations that can occur in some cases. In the device disclosed in U.S. Pat. No. 4,135,253, the sliding ring seal is avoided by a contactless gap seal that is flushed by a flow of saline directed into the pump interior. This has the disadvantage that suitable tanks and conveying systems must be provided for the saline solution, which is quite expensive.

In other designs of centrifugal pumps, the penetration of the rotating shaft through the wall and the associated rotary seals are avoided by magnetically mounting the rotor in the pump interior. Another proposal (DBOlson, June 9, 1981, “Cardiac Functions:
Total Replacement”，3rd Annual Meeting of
the Intern Society of Artificial Organs,
According to Paris, the rotor is suspended in the blood stream and driven by a magnetic field rotating outside the pump casing.

However, the known technical solutions - as partly already mentioned - are associated with important drawbacks.
Rotating through guides using sliding ring seals have the disadvantage that tornado formation can occur near the parts that rotate relative to each other. This concern cannot yet be completely eliminated in non-contact gap seals that are washed with liquid. Moreover, in this solution, a liquid other than body fluids must be continuously supplied to the blood, increasing the technical, monitoring and medical costs, and making the pump as an implantable blood pump more difficult. The disadvantage is that it reduces aptitude.

Magnetic bearings, which are still in the first stage of technological development, are designed to prevent blood cells from being damaged by the high shear forces acting on the gap between the rotor and the casing. The rotor must be held in suspension and driven by a magnetic field so that narrow gaps with the casing are avoided.

The positioning of the rotor in a stable position under the typically time-varying forces acting on the rotor requires considerable technical outlay.

It is therefore an object of the invention to provide a bearing device for the conveying element of a centrifugal pump of the type mentioned at the outset in a simple manner, outside the pump chamber through which the conveying medium flows, and avoiding rotary seals in the pump interior. to the drive unit and seal it airtight.

In this case, it is particularly desirable to provide a centrifugal pump that meets the special requirements for blood pumps and is suitable as a cardiac assist system or as an artificial heart. Although the primary purpose of the centrifugal pump of the present invention is to replace or assist a diseased heart in an organism, continuous flow or physiological Centrifugal pumps, which can also produce the desired pulsatile blood flow, are also suitable for pumping blood into an incised heart during surgery or in extracorporeal circuits during dialysis procedures.

This problem has been solved according to the invention by the measures indicated in claim 1.

The advantages achieved by the invention are the following properties: 1 The simple mechanical mounting of the conveying element avoids expensive magnetic bearings and The size of the gap with the inner wall of the pump becomes independent of the bearing device, so that the size of the gap can be chosen optimally with respect to low damage to the blood and good pump efficiency.

2. The air-tight seal of the pump interior allows intentional or unintentional infiltration of incompatible substances, or incompatible substances, e.g. in the case of a gap that is flushed with liquid. There is no need to infiltrate.

3. Airtight seals reduce the risk of tornado formation by suitably hemodynamically configuring the pump shape and choosing materials that are compatible with the appropriate blood flow.

4. Due to the sliding movement of the conveying member, the relative velocity with respect to the inner wall of the pump is reduced compared to a purely rotational movement, thereby reducing the blood-damaging shear forces associated with the relative movement.

5. According to an embodiment of the invention, there is only one rotating part in the pump and the drive, which can be mounted, for example, by a rotating magnetic field, without the need to simultaneously support the rotating part with this magnetic field. Driven.

6. The low construction height, good efficiency and the possibility of a continuous internal lining without seams and gaps of blood-compatible materials improve the suitability of centrifugal pumps as implantable blood pumps.
This is done by implanting a pump under the skin, which is connected to a rotatably supported permanent magnet, as described for one embodiment of the invention, and by means of a magnetic field in which the permanent magnet rotates outside the body. This is particularly the case when driven.

In a rotary pump device, the fluid conveying member is fixed to a holding member that performs a sliding motion, and the driven holding member protrudes through the pump casing for holding or conveying the fluid. The starting point is the recognition that rotating seals can be avoided if a sealing action is provided between the non-rotating parts of the component. The sealing element only needs to follow the changing three-dimensional curvature if the radius of the sliding movement of the holding element is selected to be suitably small or equal to zero at the fixing point of the sealing element. In this case, it is advantageous if the bearing device for the necessary compensating rotational movement is provided inside the holding or conveying element.

In a preferred embodiment, the force transmission from the rotating drive member to the holding member takes place eccentrically. In this case, the holding member extends from the drive member in the direction of extension of the axis of rotation of the drive member, so that the force is transmitted concentrically from the rotating drive member to the holding member in one direction. Rotary drives can be used. In this case, the grinding movement is produced by curving, tilting or bending the holding element. In the first-mentioned configuration, the entire holding element can be constructed rotationally symmetrically. In the last mentioned case, this applies only to the uncurved region of the holding element.

A particularly good sealing effect is achieved if the holding element and/or the conveying element are completely surrounded by the sealing element. In this case, the sealing element can advantageously form a continuously shaped diaphragm as a lining of the pump chamber. The diaphragm is made of a fluid-compatible material resistant to alternating bending loads and includes a flexible sealing member within which the conveying member is enclosed in any suitable manner as defined in the claims. It is advantageous to manufacture it in the form of a continuous bag. Polyurethane and polyurethane are advantageously used as materials.
PVC can be used.

The conveying member is a member that is rotationally symmetrical with respect to the axis specific to the grinding motion of the holding member, and the casing portion forming a gap with the conveying member is such that the shape of the gap is different from the position of the conveying member in the rotating orbit. If configured to be substantially independent, the conveying action will also be independent of the position of the conveying member. If, on the other hand, the conveying element is constructed as an incompletely rotating body and its largest cross section is oriented transversely to this when approaching the outlet, special considerations for special fluid technology conditions are required. will be done.

When used as an implanted system, the central axes of the outlet and/or inlet may be curved in a plane or in three dimensions, such that the location of the inlet and outlet is different when used as a blood pump. It is particularly advantageous if it is adapted to allow an anatomically satisfactory connection to the blood container. In order to form a complete artificial heart, it is advantageous in this case for the centrifugal pumps to be designed as twin pumps and to be driven by a common drive. With this drive device, conveying members arranged offset from each other by a predetermined angle are driven at the same rotational speed. These conveying elements can suitably have different pump characteristic curves.
This increases hydrodynamic efficiency.

Such twin pumps - with one or more drive motors - are particularly suitable for use with mass exchangers for dialysis or oxygenation. In this case both pumps are connected in series. The mass exchanger is located between the outlet of a first pump surrounding the pump in the motor front plane and the inlet of a correspondingly arranged second pump. In this case, uniform liquid distribution is ensured due to the rotationally symmetrical arrangement of the pump. Such a mass exchanger can also advantageously be used with a single pump as drive device. In both single pumps and twin pumps, the principle of a ring gap forming the inlet or outlet of the pump and connected to the mass exchanger is advantageous. This is because it is possible to produce a constant volumetric flow averaged over the circumference over time. The separation of the mass exchanger and the pump can take place in a simple manner via a snap or threaded connection.

Since the pump chamber is accessible from the outside, it can be easily replaced.

Even when used in an extracorporeal circulation circuit, parts that have come into contact with the patient's blood, or at least parts that cannot be sterilized, must be discarded after use. For this purpose, a separation point is provided which at least partially contains the pump chamber with or without the conveyor element.
In this case, the drive device can be reused. The embodiments described below relate to the connection of the motor to the shaft and the configuration of the bearing member.

The production of a flexible sealing element as an inner lining in the form of a bag, closed except for the inlet and outlet openings, involves the application of a suitably formed hollow body to an elastically hardening material in the liquid phase for a short period of time. This can be done by soaking to wet the hollow body and removing the cured bag from the molded hollow body by inverting it through an inlet or an outlet.

Advantageous embodiments of the invention are set out in the subclaims and are shown in more detail in the drawings which show different advantageous embodiments and variant embodiments of the invention.

FIG. 1 shows a first embodiment with a divided pump casing.

FIG. 2 shows another embodiment in which the sealing member is constructed as a bag that completely covers the interior of the pump.

Figures 3a to 3e show different embodiments of conveying elements for use in a rotary pump according to the invention.

FIG. 4 is a plan view showing the principle of another modified embodiment of the rotary pump of the present invention.

FIG. 5 is a plan view showing the principle of another modified embodiment of the centrifugal pump of the present invention.

FIG. 6 is a diagram illustrating the area with the drive device of another embodiment of the centrifugal pump according to the invention. The embodiment shown here can be complemented by the upper part of the pump shown in FIG.

FIG. 7 is a sectional view of another embodiment of the centrifugal pump of the present invention.

FIG. 8 is a diagram showing the driving range of an embodiment of an implantable centrifugal pump according to the present invention.

FIG. 9 is a diagram showing an embodiment of a centrifugal pump according to the present invention having a twin structure.

FIG. 10 is a cross-sectional view of an embodiment of the invention in which reusable and non-reusable components are separable.

FIG. 11 is a diagram showing a pump separated in a different manner from that shown in FIG. 10.

FIG. 12 is a detailed view of the coupling device between the reusable motor shaft and the pump body including the non-reusable pump chamber;

FIG. 13 shows a twin pump used with a mass exchanger.

FIG. 1 shows an axial longitudinal section of a first embodiment of a centrifugal pump according to the invention. In this case, the cross-sectional line - in FIG. 4 is indicated by a dashed line.

Drive device 1, which advantageously consists of a direct current motor
has a rotating shaft 2 on which a bearing 3 is inserted and fixedly connected to the shaft. The bearing 3 forms the drive member of the conveying member of the pump, which will be explained later, and has bearings 4 and 5;
By means of these bearings 4 and 5, a shaft 6 forming a holding element, which is inclined at an angle α with respect to the drive axis, is rotatably guided. The angle α is approximately 30° in the illustrated embodiment.

The axis 6 and the extended center line of the drive shaft 2 intersect at a point 7. According to the invention, the shaft 6 is connected to a diaphragm-like elastic sealing element 15 . This sealing element 15 bridges the area (point 7) where the shaft 6 penetrates the pump casing and is connected to the pump casing around this area. In this embodiment, the shaft 6 does not rotate about its own longitudinal axis, but is held in position relative to the pump casing by a sealing member. The shaft 6 performs a grinding motion when the bearing 3 rotates. However, a relative movement between the shaft 6 and the bearing 3, which performs a precessing movement but does not rotate, is made possible by the bearings 4 and 5. At the height of point 7, the grinding movement performed by shaft 6 is minimal.

The connection point or contact limit of the elastic sealing member 15 to the shaft 6 and the pump casing is at point 7.
placed near an axial height corresponding to .
Thereby, the deformation of the sealing member 15 in the range 8 is kept small. It is clear that in this case it is advantageous if the shaft 6 is mounted as shown in FIG. That is, the space around the point 7 is free for connection with the sealing member 15 and is occupied by the sealing member 15. Since point 7 is substantially stationary during the grinding movement, the deformation of the sealing member due to its connection with the shaft is extremely small in the area of this point. This is advantageous for the durability of the seal member. The bending radius occurring in the sealing element is effectively additionally reduced by the region 8 being predeformed, especially in the form of a wave. Flexible seal bearings 4, 5
Since it is also exposed to torsional load due to the frictional force of the bearing, the bearing frictional force and the torsion resistance of the seal member 15 are mutually tuned.

By means of the precessing movement of the shaft 6, the center point 12 of the conveyor element 9, which is designed as a sphere, is moved in the direction of the arrow 20 along a rotational path 22 shown in FIG. This orbit of rotation is indicated by line 10 in FIG. Point 21 is shown in the same direction, indicated by W in the drawing, in any of the precessing positions as shown in FIG.

In the embodiment shown in FIG. 1, the pump casing is divided into an upper part 11 and a lower part 16. In this case, the seal member 1
5 extends to the overlapping limits of both parts.

If the pump casing is made of an elastic material, e.g. blood-compatible plastic, polyurethane, the two parts that overlap each other in the tapered area of the pump casing form are the lower part 16.
They are connected to each other by a snap connection without additional retaining members, with the sealing members over the green of the caps gripped.

the fluid is rotated by the movement of the conveying member;
At high velocity in the tangential direction, the fluid leaves the outlet 13 (arrow in FIGS. 1 and 4) forming a diffuser-like outlet, while at the same time new fluid flows through the inlet 14 forming an axial inlet. through which it flows into the low pressure region of the volute core in the direction of the arrow. The configuration of the inlet 14 with a constricted cross-section and the outlet 13 with a widened cross-section accelerates the fluid as it enters and directs it into the rotating volute core of liquid. When passing through a diffuser-like outlet, an additional pressure is created due to the flow being restricted.

In one advantageous embodiment of the invention, the tangential outlet 13 is inclined at a positive or negative angle with respect to the cutting plane, and is indicated by an angle not shown in the drawing but shown in dash-dotted lines. It can be arranged as shown. This advantageously results in a slight deflection of the liquid flow passing through the pump interior for angles >0. On the other side, the angle>
A slope of 0 is advantageous for adaptation to anatomical connection conditions. For this reason, in an embodiment not shown, the central axes of the outlet and/or inlet are designed to lie in one plane or to be curved three-dimensionally. This allows a space-saving, hemodynamic and anatomically advantageous connection of the blood pump.

The flexible sealing element 15 forms the pump lining and in the area 17 forms a lining surrounding the conveying element 9 and is constructed as a continuously molded diaphragm. The diaphragm is made of a fluid compatible material that is resistant to alternating bending loads. The interior of the lower part 16 of the pump housing is close to the sliding range of the holding member (shaft 6) and is enlarged in the form of a hopper. A further housing part 16 a fitted to the lower part 16 surrounds the bearing 3 .

In the embodiment shown in FIG. 2, in which the parts not provided with reference numbers correspond approximately to the parts shown in FIG. 1, the inner lining of the pump interior is wetted by the conveying medium. It consists of a continuous bag 18 produced, for example, by the dipping method. This bag 18 forms, in addition to the inlet and outlet linings, the area in which the sealing element deforms elastically during operation. When the pump is used to transport blood, the bag 18
is made of or coated with a material that is compatible with blood. This is, for example, coated or uncoated polyurethane. Bag 18 may be constructed entirely or partially of two or more layers configured to be movable relative to each other. In this case the sliding material provided between the layers facilitates sliding.
This sliding material has an advantageous effect on the durability of the flexible region 8 which is subjected to alternating bending loads.

3a to 3e show variations of the conveying member 9. FIG. This conveyor element 9 is constructed as a substantially rotationally symmetrical element with respect to its axis 6. According to FIGS. 3a to 3b, this element is of completely or partially spherical, conical or elliptical design. In this case, the parts of the upper part of the housing which form the gap 19 with the conveying member are designed in such a way that the gap width is constant or approximately constant in every grinding movement position.

FIG. 5 shows a modified embodiment of the embodiment of FIG. In this case, the center point 23 of the rotary track 22, along which the center point of the conveying member 9 moves, is eccentrically rotated by a distance e with respect to the center 24 of the casing and an angle β with respect to the perpendicular to the outflow direction. It is located. In this way, the gap set between the conveying element and the housing interior 25 in a simple rotary basic form is related to the gap width relative to the circumference of the rotation path of the conveying element. It can be varied to minimize shear forces and optimize pump efficiency. In particular, the spacing of the rotating body to the edge of the outlet is minimized.

Advantageously, the conveying element can also consist of one or more straight or curved three-dimensional surface segments. It is particularly advantageous in this case for the conveying element to be a partial segment of a hollow cone or hollow ellipsoid (FIG. 3a). Third
In the embodiment shown in FIG. e, the conveying member consists of two curved disks. As a result, the conveying element forms an incomplete body of rotation that appears circular only from each direction.

In the embodiment of the rotary pump according to the invention shown in FIG. 6, the bearings 4 and 5 of the sliding shaft 6 shown in FIG. 1 can be omitted. In this case, the shaft 27 is fixedly connected to the rotating part 26. This results in a relative movement between the rotating and grinding shaft 27 and the non-rotating but grinding conveying element 9 and the sealing element 30 placed on this conveying element 9. In the embodiment of FIG. 6, this relative movement is absorbed by bearings 28, particularly plain bearings. A hollow chamber 29 connected to the pump chamber and separated from the pump chamber only by a sealing element 30, receiving the element 26 and the motor 1.
is filled with fluid. This fluid can be introduced and removed for cooling and/or lubrication purposes via inlets and outlets 32 and 33, or it can be used solely for bearing lubrication as shown in FIG. It will be done. In FIG. 6, the drive unit 1 can be designed, for example, as a rotary direct current motor. This DC motor is cooled via a gas flow. In this case, the inlet or outlet 33 can also be used as a passage for the cable 34 of the motor.

In other embodiments, the drive unit 1 is constructed in the form of a unit driven by a cooling and/or lubricating fluid, in particular a gas or liquid turbine. On the other hand, the fluid to be conveyed can also be used as a cooling medium for the drive device.

In a variation of the embodiment shown in FIG. 6, shaft 27 and drive shaft 2 form a single consistent shaft, as shown in FIG. The elongated drive shaft consists of continuously transitioning straight or curved segments. Relative movements between the stationary inner lining 35 forming the sealing element and the conveying element are also absorbed in this case by suitable bearings 28. In this case, the inner lining 35 is connected to the shaft 36.
It is curved following the grinding motion.

The inflow 14 of the conveying medium can take place axially from above into the pump interior, as shown in FIG. 1, or from the region 8 behind the flexible sealing element, as shown in FIG. It will be done. In the latter case, the inflow does not necessarily have to take place axially. The latter direction of inflow has the advantage that the fluid also flows around the sliding area between the curved shaft 36 and the flexible inner lining 35 and that the frictional heat is absorbed effectively.

Another embodiment of the lower part of the pump is shown in FIG. In contrast to the embodiment shown in FIG. 6, the arrangement for supporting the rotating member 26 in the housing 31 is not shown in detail. The member 26 is rotated by a rotating magnetic or electromagnetic field outside the casing. For this purpose, the rotating element 26 is constructed like a disc of a disc-shaped rotor motor or has one or more permanent magnets.

Complete encapsulation of the pump within a casing 31 of a body-compatible material allows the centrifugal pump to be implanted under the skin or tissue 38 of a living body, allowing the pump to be removed outside the body without skin passage. It can be driven by a rotating magnetic or electromagnetic field. This magnetic or electromagnetic field is rotated by drive means (not shown) and the rotating member 26
is schematically shown in the form of a ring magnet 37 driving the .

Centrifugal pumps deliver a constant, pulsating flow with a constant rotational speed and a constant delivery degree. With the pump of the invention it is possible to produce a physiologically or nearly physiologically pulsating flow with a rotational speed that varies in a temporal cycle.

Forces are generated by the grinding conveyor member 9 that can lead to unbalance during operation.
In order to keep this as low as possible, the transport member is made of a material with approximately the same density as the transport medium.

In the embodiment of FIG. 9, the centrifugal pumps are constructed as twin pumps with a common drive 39. The arrangement of sealing members 40 and 41 corresponds to that shown in FIG.

By means of both conveying members 42 and 43 offset by an angle of 180° as shown in FIG.
Static imbalances due to the arrangement of the transport members are compensated for. By selecting other angles as said angle, structural dynamic imbalances can also be compensated in a simple manner with suitable compensation weights. In this case, the pump's delivery characteristics are independent of the angle. Weight compensation is advantageously carried out using the shape of the conveyor element shown in FIG. The shape of this conveying element differs from a spherical shape, thereby making it possible to vary the mass distribution.

In order to use the twin pumps as a double bypass pump or as a complete artificial heart, it is important to deliver the same blood volume flow from both pumps at the same rotational speed but at different counterpressures. This is achieved by suitably setting the pump and its delivery characteristics.

In FIG. 10 an embodiment of the centrifugal pump of the present invention for use as a blood pump is shown. The centrifugal pump is shown disassembled into a reusable part 44 and a single-use part 45. The upper part of the pump, which forms the single-use part 45, can be snapped together along the separation line A with the part containing the drive motor 46.
In this case, the necessary sealing action is the seal ring 4
It is caused by 7. By configuring in this manner, a part that is difficult to clean and sterilize can be configured as a part that will not be reused, and a part that is difficult to clean and sterilize can be constructed with a simple operation after surgery where circulation must be maintained by extracorporeal means. parts can be exchanged. In the illustrated embodiment, the upper part of the pump 4
5 is permanently equipped with hose conduits 48 and 49. This hose conduit cannot be reused at the same time.
Make connections to adjacent components.

In the pump of the invention, the separation point between the non-reusable and reusable parts can also be arranged such that the entire pump chamber that comes into contact with the patient's blood belongs to the non-reusable part.

Advantageously, the separation point which makes it possible to separate the disposable part extends between the drive part and the rotary part of the pump. Of course, the separation points are chosen according to the principle that all the expensive parts and all the parts that come into contact with the patient's blood are combined into two separable units. This arrangement is the 11th
This is indicated by the separating line B in the illustrated embodiment. The non-reusable part 50 has a closed pump chamber. In this case, the conveying member 51 also belongs to the part that cannot be reused.

The part with the drive motor 52 and the holding element 53 must be able to be removed in a direction oblique to the main axial axis - due to the grinding movement that is to be produced by the drive. To facilitate this process, a cover part 54, which has parts for receiving the side and bottom areas of the motor, can be removed from part 50. The part 54 can be configured - depending on requirements - as a non-reusable part or as a reusable part. The casing illustrated here is only an example; depending on other ambient conditions,
It is also possible to permanently combine reusable motors with parts or components that are likewise reusable. In this case, the pump chamber is integrated with a hose or a connection system for the medium to be conveyed, and the pump drive is connected with a further control device or controller.

FIG. 12 details one embodiment of the separation point that can be provided between the non-reusable and reusable parts. In this case, the conveyor element 56 of the pump chamber 57 likewise belongs to the non-reusable part. A hollow conical member 58 is fixedly connected to the holding pin 55 . This hollow conical member 58 can be fitted onto a corresponding conical extension 59 of the shaft 60 of the motor 61 . This eliminates special bearings for the conveying elements.

The pin 55 of the transport member engages in the groove 62 of the cone 59 when assembling both parts. In this case, the drive motor 61 can optionally be rotated slowly for the assembly process. Additional permanent magnets 63 and 64 are provided in the conical part in order to obtain a "snap coupling effect". This permanent magnet interacts alternately with the ferromagnetic counterpart of the conical cap 58 and is capable of absorbing forces directed in the direction of the arrow 65. As a result, the motor shaft 6
0 takes over the support of the rotating pump body. The pump chamber, including the conveying member, is therefore structurally simple. Centering and positioning of the pump body with respect to the motor 61 is performed by a collar 66 that is connected to the pump casing. The notch inside this collar 66 is matched to the shape of the motor 61. 1st
In FIG. 3, twin pumps are shown which are used to supply fluid to the mass exchanger 67 which circularly surrounds the drive motor 68. Two pump chambers 69 and 70 are provided at both ends of the device and each form a unit. Both pumps are connected in series, which improves hydrodynamic efficiency. The conveying elements 71 and 72 of both pumps are reusable in the illustrated embodiment.

The mass exchanger is used as an oxygenator in an extracorporeal circuit or for performing dialysis.
It should be noted in particular that in the illustrated pump, the inlet side (lower pump) on the one hand and the outlet side (upper pump) on the other hand are closed circularly and are constructed as ring gaps 73 and 74, thus A uniform inflow of fluid from the entire suitably designed inlet region of the mass exchanger and a uniform fluid outflow from the entire outflow region of the mass exchanger are provided. In this case, use is made of the fact that in the centrifugal pump of the invention the flow conditions that occur are rotationally symmetrical - in terms of mean time. (The twin pumps shown can also be configured so that both pumps are mounted on the mass exchanger with their respective external drive motors. In this case two separate motors would be required. However, the physical exchanger can have a cylindrical internal cross-section.

In order to periodically control the rotational speed of the pump to produce an at least approximately physiologically pulsating flow, it is advantageous to use a clock pulse generator which operates the pump intermittently at the natural heart frequency. . This clock pulse generator is not shown in the drawings, but the components necessary for this purpose are obvious to those skilled in the art.

Constructing the conveying member from a plurality of materials or from a material or materials and a hollow chamber such that the average density of the conveying member is the same or approximately the same as the density of the fluid; In order to dynamically balance the fluid by considering it, experiments can be carried out using a suitable unbalance measuring device until this condition is achieved. In addition to providing a hollow space in the illustrated embodiment, it is also possible to vary the dimensions of the conveying element and the holding element.

The illustrated embodiment is only a preferred embodiment, and the pump of the invention can be used for many other purposes and in many other configurations. In this case, the details need to be adapted to the intended use, but this can be easily done by a specialist based on the embodiments described above.