EP0085702A1

EP0085702A1 - Sealed centrifugal pump for the smooth pumping of fluids

Info

Publication number: EP0085702A1
Application number: EP82902637A
Authority: EP
Inventors: Ulrich Baurmeister; Klaus Affeld
Original assignee: BAURMEISTER Ulrich Dr
Current assignee: BAURMEISTER, ULRICH, DR.
Priority date: 1981-08-19
Filing date: 1982-08-19
Publication date: 1983-08-17
Also published as: JPS58501264A; JPH0347870B2; DE3133177A1; WO1983000725A1

Abstract

La pompe comprend un organe de pompage (9) doté d'un mouvement circulaire dans une chambre de pompage, ce qui provoque la rotation du fluide. L'organe de pompage (9) est fixé sur un support (6) et exécute un mouvement circulaire tout en ayant en moyenne une orientation spatiale fixe par rapport à la chambre de pompage. Le support (6) constitue une liaison mécanique entre l'organe de pompage (9) et un organe d'entraînement rotatif (1) disposé en dehors de la chambre de pompage, et exécute une nutation. Le rayon de nutation du support a, dans une direction parallèle au rayon du mouvement circulaire, une valeur diminuée à l'endroit où le support pénètre la paroi de la chambre de pompage par rapport à la valeur du rayon du mouvement circulaire de l'organe de pompage (9). Une membrane élastique d'étanchéité (15) est reliée hermétiquement, d'une part, avec la paroi de la chambre de pompage au voisinage de la pénétration du support dans la chambre de pompage et, d'autre part, avec le support et/ou l'organe de pompage rotatifs ayant une orientation spatiale fixe à l'intérieur de la chambre de pompage.The pump comprises a pumping member (9) having a circular movement in a pumping chamber, which causes the rotation of the fluid. The pumping member (9) is fixed on a support (6) and performs a circular movement while having on average a fixed spatial orientation with respect to the pumping chamber. The support (6) constitutes a mechanical connection between the pumping member (9) and a rotary drive member (1) disposed outside the pumping chamber, and performs nutation. The nutation radius of the support has, in a direction parallel to the radius of the circular movement, a reduced value at the point where the support penetrates the wall of the pumping chamber relative to the value of the radius of the circular movement of the member. pumping (9). An elastic sealing membrane (15) is hermetically connected, on the one hand, with the wall of the pumping chamber in the vicinity of the penetration of the support into the pumping chamber and, on the other hand, with the support and / or the rotary pumping member having a fixed spatial orientation inside the pumping chamber.

Description

Hermetically sealed centrifugal pump for gentle

Promotion of fluids

Description

The invention relates to a centrifugal pump (centrifugal pump) of the type specified in the preamble of claim 1 and a method for its production.

As is known, centrifugal pumps for the gentle delivery of fluids and in particular as blood pumps are well is suitable and has the advantage over a diaphragm pump of a simpler construction, a smaller construction volume, a simpler regulation and / or control and a high operational safety. With a suitable design of a centrifugal pump to be used as a blood pump, the damage to the delivered blood can be kept very low. The blood centrifugal pump is suitable for being implanted in a living body to support or replace the heart. It is also suitable for replacing the peristaltic pumps that are currently used frequently in medicine, which are mechanically more complex and larger than a centrifugal pump and produce harmful abrasion (spalation) due to the material movement.

The known centrifugal pumps contain a rotating conveying element, the rotor, which is mounted outside the pump chamber in one group of centrifugal pumps. The rotor shaft must be guided through the pump housing and sealed against it by a rotary seal. An example of this is the Gleitringdich¬ used in the arrangement of US-PS 3,864,055 is processing. Such a mechanical seal is critical because of a ^'possible thrombus. In the arrangement according to US Pat. No. 4,135,253, the mechanical seal was avoided by a contact-free gap seal which is flushed with a liquid stream of physiological saline solution directed into the pump interior. The disadvantage here is that a separate reservoir and a transport system for the saline solution must be provided, which represents a considerable outlay. In another type of centrifugal pump, the wall bushing of a rotating shaft and the associated rotary seal are avoided by the rotor being magnetically mounted in the interior of the Purap. According to a further proposal (DB Olson, "Cardiac Function: Total Replace ent", lecture on July 9, 1981, 3rd Annual Meeting of the International Society of Artificial Organs, Paris), the rotor is driven by a magnetic field rotating outside the pump housing freely suspended and driven in the bloodstream.

However, as already mentioned in part, the known technical solutions are associated with serious disadvantages. The rotating bushing with a mechanical seal is associated with the risk of thrombus formation in the vicinity of the parts rotating against one another. With the non-contact gap seal, which is flushed with a stream of liquid, this danger has not yet been completely eliminated. Another disadvantage of this solution is that a foreign fluid has to be continuously added to the blood, which increases the technical, maintenance and medical expenditure and worsens the suitability of the pump as an implantable blood pump.

In the case of magnetic storage, which is still in a phase of technical development, the rotor must be held in suspension by magnetic fields and driven in such a way that narrow gaps between the rotor and housing are avoided in order to keep the blood cells active not to destroy high shear forces. The posi

OMPI The operation of a rotor in a stable position with forces that act on the rotor in a time-varying manner is associated with considerable technical outlay.

The invention is therefore based on the object of providing the position for the delivery element of a centrifugal pump of the type mentioned at the outset in a simple manner outside the pump chamber through which the delivery medium flows and hermetically sealing the inside of the pump to the drive while avoiding a rotary seal.

In particular, a centrifugal pump is to be created which meets the special requirements for a blood pump and which is therefore suitable as a cardiac support system or cardiac replacement. Although the primary purpose of the centrifugal pump according to the invention is to replace or support the diseased heart of a living body, the centrifugal pump, which can produce both a continuous flow and a physiologically better tolerated pulsating blood flow, is also suitable during the operation to pump blood on an open heart or in dialysis treatment in an extracorporeal circuit.

This object is achieved by the measures specified in claim 1.

The advantages achieved with the invention consist in particular in the following achieved properties: 1. The simple mechanical mounting of the conveying element means that complex magnetic mounting can be avoided and the gap thickness between the conveying element and the inner wall of the pump is a variable which is independent of the bearing and which can be optimized with regard to low blood damage and good pump efficiency.

2. Due to the hermetic sealing of the pump interior, no intentional or unintentional penetration of substances foreign to the body is possible or necessary, such as in the case of a liquid-flushed gap.

3. The hermetic seal reduces the risk of thrombus formation if the pump shape is hemodynamically designed and appropriate blood-compatible materials are selected.

4. Due to the wobbling movement of the conveying element, its relative speed with respect to the pump inner wall is reduced in comparison to a purely rotating movement, as a result of which the shear forces which damage the blood and are dependent on the relative movement are correspondingly reduced.

5. According to a further developed embodiment, the pump can be simplified to such an extent that only a single rotating part exists in the pump and drive, which can be driven, for example, by a rotating magnetic field, without this magnetic field also having to take over the bearing forces at the same time. ^•

OMPI 6. The small size, the good efficiency and the possibility of a seamless and gap-free coherent inner lining made of blood-compatible material improves the suitability of the centrifugal pump as an implantable blood pump. This is particularly the case when the pump, as described with the aid of an exemplary embodiment, is coupled to a rotatably mounted permanent magnet, is implanted under the skin and the permanent magnet is driven by means of a magnetic field rotating outside the body.

The invention is based on the knowledge that a rotary seal can be avoided in a centrifugal pump arrangement if the conveying element for the fluid is fastened to a supporting element that performs a wobbling movement in such a way that the sealing effect in the area of the passage of the driving supporting element the pump housing can be achieved between the latter and a non-rotating part of the carrying or conveying element. If the radius of the wobble movement of the support element at the fastening location of the sealing element is chosen to be correspondingly small or zero, the sealing element essentially only needs to follow an alternating spatial curvature. Bearings for the necessary compensatory rotational movements are expediently provided in the interior of the carrying / conveying element.

In a preferred development, the force transmission from the rotating drive element to the support element takes place eccentrically, the support element extending from the drive element in the direction of the extension of the rotational

OMPI Axis of the drive element extends so that a conventional rotary drive can be used, as well as in an embodiment in which the power transmission from the rotating drive element to the support element takes place concentrically, the wobble movement being caused by a bending, inclination or kinking of the support element. In the first-mentioned embodiment, the entire support element can be made rotationally symmetrical, which in the latter case applies only to the non-curved areas of the support element.

A particularly good sealing effect can be achieved if the support element and / or the conveying element is completely enclosed by the sealing element. In this case, the sealing element can advantageously form a coherently shaped membrane as the lining of the pump chamber, which consists of a material which is matched to the fluid and is durable with respect to alternating bending and which, in the form of a coherent bag, in which the conveying element is inserted and which includes the flexible sealing membrane, can be produced cheaply. Polyurethane and PVC are preferably used as materials.

If the conveying element is one with respect to the The characteristic axis of the wobble movement of the support element is rotationally symmetrical body, the part of the housing which forms a gap with the conveying element being designed such that the gap shape is essentially independent of the position of the conveying element on the circular path the funding effect is independent

from the position of the conveyor element. If the conveying element is designed as an incomplete rotating body, a maximum cross section being directed transversely to the outflow opening when approaching the outflow opening, on the other hand, particular consideration can be given to particular flow-related conditions.

When used as an implantable system, it is particularly advantageous if the central axis of the outlet and / or inlet are curved in one plane or in space, in particular in such a way that the position of the inlet and outlet make an anatomically favorable connection to the Allows blood vessels when used as a blood pump. In order to form a complete "artificial heart", the centrifugal pump is preferably designed as a twin pump and provided with a common drive, by means of which the conveying elements arranged at an angle to one another are driven at the same speed and can accordingly have different pump characteristics, whereby the hydrodynamic efficiency increases.

Such a twin pump - with one or two drive motors - is particularly suitable for use with a substance exchanger for dialysis or an artificial lung. In this case, the two pumps are connected in series, the material exchanger being located between the outflow opening of the first pump surrounding the pump in the plane of the motor front surface and the correspondingly arranged one. Inflow opening of the second pump is located. Because of the rotationally symmetrical arrangement of the

CMPI • V IP Pump is guaranteed an even distribution of liquid. Such mass exchangers can also be used advantageously as a drive with a single pump. In the case of both the single and the twin pumps, the principle of an annular gap which forms the inlet and outlet opening of the pump and which is connected to the material exchanger has proven to be. This is advantageous because it enables a volume flow that is constant over the circumference over time to be generated. The material exchanger and pump (s) can be separated in a simple manner using a snap or screw connection.

The pump chambers are accessible from the outside, so that they are easily accessible for replacement.

In other applications in extracorporeal circulation, too, the parts which come into contact with the patient's blood - or at least the non-sterilizable parts - must be destroyed after use. For this purpose, an interface is provided, which at least partially encompasses the pump chamber with or without including the conveying element. The drive is retained for further use. Preferred embodiments described below relate to the design of the coupling and mounting elements with respect to the motor shaft.

The flexible sealing element is produced as an inner lining closed in the form of a coherent bag except for the inflow and outflow opening, by briefly immersing a correspondingly shaped hollow body in an elastically curing one

OMPI Material in the liquid phase, so that only a wetting of the mold takes place, the cured bag being removed from the mold by means of everting through the inflow or outflow opening.

Advantageous further developments of the invention are characterized in the subclaims or are described in more detail in the description below of various preferred embodiments and variants of the invention. Show it:

FIG. 1 shows a first exemplary embodiment of the invention with a divided pump housing,

FIG. 2 shows a further exemplary embodiment in which the sealing element is designed as a bag that completely lines the interior of the pump,

FIGS. 3a to e different embodiments of a conveyor element for use with the rotary pump according to the invention,

FIG. 4 shows a schematic diagram of another embodiment of the rotary pump according to the invention in a top view,

FIG. 5 is a top view of another embodiment of the centrifugal pump according to the invention,

FIG. 6 shows the area of the drive of another embodiment of the centrifuge according to the invention galpump, the embodiment shown here can be supplemented by the upper part of a pump according to FIG. 1,

FIG. 7 shows a further embodiment of the centrifugal pump according to the invention in a sectional view,

8 shows the drive area of an embodiment of the centrifugal pump according to the invention, which is implantable.

FIG. 9 shows an embodiment of the centrifugal pump according to the invention in a “twin arrangement”,

FIG. 10 shows a sectional illustration of the exemplary embodiment of the pump according to the invention with a possible division for disposable and reusable components,

FIG. 11 shows a pump corresponding to that in FIG. 10 with a different division,

FIG. 12 shows a detailed representation of the coupling between the shaft of the reusable motor and a pump chamber including pump body and intended for single use

Figure 13 shows a twin pump for use with a mass exchanger.

1 shows an axial longitudinal section through a first embodiment of the centrifugal pump according to the invention, the course of section IV-IV of the 4 as a dash-dotted line.

A drive device 1, which preferably consists of a direct current motor, contains a rotating shaft 2, onto which a bearing body 3 is pushed and firmly connected to the shaft. The bearing body 3 forms the drive element for the pumping element of the pump listed below and carries bearings 4 and 5, by means of which the axis 6, which is inclined by the angle a to the drive shaft axis and forms a support element, is rotatably guided. In the exemplary embodiment shown, the angle a is approximately 30 ^* .

The axis 6 and the extended center line of the drive shaft 2 intersect at a point 7. According to the invention, the axis 6 is connected to a membrane-like elastic sealing element 15, which extends the area of penetration (point 7) of the axis 6 through the pump housing 8 bridged and connected around this puncture area with the pump housing. In this exemplary embodiment, the axis 6 cannot rotate about its own longitudinal axis, but is held in place by the sealing element in a spatially fixed orientation with respect to the pump housing. When the bearing body 3 rotates, it executes a wobbling movement, the relative movement between the wobbling but not rotating axis 6 and the bearing body 3 being made possible by the bearings 4 and 5. At point 7, the wobble movement, which is carried out by the axis 6, is a minimum.

The connection point or the limits of contact for the elastic sealing element 15 with the axis 6 and the

Pump housing located near the axial height of point 7. As a result, the deformation of the sealing element 15 in the region 8 is kept low. The advantage of mounting the shaft 6 according to FIG. 1 is clear here: the space around the point 7 is namely free for the connection to the sealing element 15 and can be taken up by the latter. Since point 7 is almost at rest during the wobble movement, the deformation of the sealing element due to the connection with the axis is very small in the area of this point, which is decisive for the fatigue strength of the sealing element. The bending radii occurring in the sealing elements can also be effectively reduced in that the region 8 is preformed, in particular is preformed in a wave shape. Since the flexible seal is also subjected to torsion due to the frictional forces of the bearings 4 and 5, the bearing frictional forces and the torsional rigidity of the sealing element 15 are matched to one another.

As a result of the wobbling movement of the axis 6, the center point 12 of a conveying element 9 designed as a ball moves on a circular path 22 shown in FIG. 4 in the direction of an arrow 20. This circular path appears in FIG. 1 as line 10. Point 21 shows according to FIG 4 in each wobble position in the same direction, which is designated W in the drawing.

In the exemplary embodiment shown in FIG. 1, the pump housing is made divided into an upper part 11 and a lower part 16, the sealing element 15 extending up to the overlapping border area of the two parts. stretches. When the pump housing is produced from an elastic material, such as the blood-compatible plastic polyurethane, the two parts overlapping one another in a tapering region of the shape of the pump housing, including the sealing element projecting beyond the edge of the lower part 16, can be "snapped" without connect additional holding elements.

The fluid is set in rotation by the movement of the conveying element and flows tangentially at high speed through the diffuser-like outlet 13 (arrow, FIGS. 1 and 4) forming the outflow opening, while at the same time new fluid flows over the axial, the inlet 14 forming the inflow opening flows into the low-pressure region of the vortex core in the direction of the arrow. By designing the inlet 14 with a cross-sectional constriction and the outlet 13 with a cross-sectional widening, the fluid is accelerated upon entry and the liquid jet is directed into the vortex core of the rotating fluid. When passing through the diffuser-like outlet, an additional pressure is built up due to the deceleration of the flow that is achieved.

In an advantageous development of the invention, the tangential drain 13 can be arranged inclined by a positive or negative angle o with respect to the section plane IV-IV, as it is not shown in the drawing, but is indicated by the free leg of the angle 9 shown in dash-dotted lines is thereby advantageously achieved that at an angle Ψ ^ 0 the deflection of the liquid jet ^' when flowing through the

OM Pump interior is less. On the other hand, an inclination by an angle Ψ ^ 0 is possibly more favorable for adaptation to the anatomical connection conditions. For this reason, according to a (not shown further development), the central axes of the drain and / or feed are formed lying in one plane or curved in space, as a result of which both the space-saving and the hemodynamically and biologically favorable connection of the blood pumps are made pe becomes possible.

The flexible sealing element 15 forms the pump lining and, in the region 17, the casing of the conveying element 9 and is designed as a coherently shaped membrane which is made of a material which is adapted to the fluid and is durable against alternating bending. The shape of the interior of the lower part 16 of the pump housing nestles against the wobble region of the support element (axis 6) and widens in the shape of a funnel. A further housing part 16a which is adapted to the lower part 16 surrounds the bearing body 3.

In the exemplary embodiment shown in FIG. 2 - in which the elements not provided with reference numerals essentially correspond to those shown in FIG. 1 - the inner lining of the pump (s) interior wetted by the pumping medium consists of, for example, an immersion method manufactured coherent bag 18, the next to the lining of. Inlet and outlet ■ also forms the region 8 of the sealing element which is elastically deformed during operation. When using the pump for blood delivery, the bag 18 is made of a material that is friendly to blood contact. posed or coated with such. It is coated or uncoated polyurethane. The bag 18 can consist entirely or partially of two or more layers which are designed to be displaceable relative to one another, a lubricant provided between the layers facilitating the displacement. This has a favorable effect, in particular with regard to the fatigue strength of the flexible region 8 which is subjected to alternating bending.

FIGS. 3a to 3e show variants of designs of the conveying element 9. This is designed as a body which is essentially rotationally symmetrical with respect to its axis 6 and which, according to FIGS. 3a to 3d, is wholly or partly spherical, conical, ellipsoidal, wherein that part of the upper housing part 11 which forms a gap 19 with the conveying element is shaped such that the gap width is constant or approximately constant in each wobble position.

FIG. 5 shows a modification of the exemplary embodiment according to FIG. 4, in which the center 23 of the circular path 2, on which the center of the conveying element 9 moves, relative to the center 24 of the housing by a distance e (and an angle β relative to the perpendicular rotated to the outflow direction) is arranged eccentrically. In this way, the gap between the conveying element and the housing inner wall 25, based on the circumference of the circular path of the conveying element, can be designed in a simple manner with rotationally symmetrical basic shapes in such a way that the gap with the gap width dependent shear forces are minimal and the pump efficiency is optimal. In particular, the distance of the rotary body from the edge of the outflow opening is made to a minimum.

The conveying element can advantageously also be composed of one or more straight or curved segments forming spatial surfaces. In particular, the conveying element is a sub-segment of a hollow sphere or a hollow ellipsoid, as the embodiment according to FIG. 3a shows, which according to the example shown in FIG. 3e is composed of two curved circular disks. The bodies thus form incomplete bodies of revolution which only offer the view of a circular shape from individual directions.

In the embodiment of the rotary pump according to the invention shown in FIG. 6, the bearings 4 and 5 of the wobbling axis 6 according to FIG. 1 can be dispensed with. Here, an axis 27 is fixed to the rotating body 26. As a result, a relative movement occurs between the rotating and tumbling axis 27 and a non-rotating, tumbling conveying element 9, including the sealing element 30 covering it. In the exemplary embodiment according to FIG. 6, this relative movement is absorbed by the bearings 28, in particular by plain bearings. A cavity 29 which receives the element 26 and the motor 1, adjoins the pump chamber and is separated therefrom only by the sealing element 30, is filled with a fluid which either flows through the inlet and outlet openings 32 and 33 for the purpose of cooling and / or Lubrication is supplied and discharged or, as in the embodiment according to FIG. 8, only serves to lubricate the bearings. In FIG. 6, the drive unit 1 can be formed, for example, by a "dry-running" DC motor that is cooled by a gas stream. In this case, the inlet or outlet 33 is simultaneously used as a channel for a cable connection 34 for the motor.

In another embodiment, the drive unit 1 is designed as a unit driven with the cooling and / or lubricating fluid, in particular in the form of a gas or liquid turbine. On the other hand, it is also possible to use the fluid to be pumped as a coolant for the drive.

When the embodiment according to FIG. 6 is modified, the shaft 27 and the drive shaft 2 represent a single continuous shaft, as shown in FIG. 7. The elongated drive shaft is composed of straight or curved segments which continuously merge into one another. The relative movement between the fixed inner lining 35 forming the sealing element and the conveying element is again taken up here by corresponding bearings 28, the lining 35 following the wobbling movement of the axis 36 in its curvature.

The inflow 14 of the delivery medium takes place either axially from above into the pump interior, as shown in FIG. 1, or according to FIG. 7 from behind in the area 8 of the flexible sealing element. In the second case, the inflow is not necessarily axial. The latter direction of inflow has the advantage that the sliding area between the curved shaft 36 and the flexible inner lining 35 is also flowed around well to dissipate frictional heat.

A further embodiment of the pump lower part is shown in FIG. 8. In contrast to the embodiment shown in FIG. 6, the mounting of the rotating body 26 in the housing 31 is not shown in detail. The body is kept in rotation by a rotating magnetic field or electromagnetic field outside the housing. For this purpose, the rotating body 26 contains one or more permanent magnets or is designed like the disk of a disk rotor motor.

The complete encapsulation of the pump in the housing 31 made of body-compatible material allows an implantation of the centrifugal pump under the skin or the tissue 38 of a living body and a drive of the pump without a skin passage by means of a magnetic or electromagnetic field rotating outside the body, which in the form of a ring magnet 37 is shown schematically, which is set into rotation by drive means (not shown) and drives the body 26 accordingly.

The centrifugal pump delivers a constant, pulseless liquid flow at constant speed and constant head. The pump according to the invention can be used to generate a physiologically or approximately physiological pulsatile flow by changing the speed in the time cycle.

OMP V. Ir In operation, the wobbling conveyor element 9 emits forces which can lead to an imbalance. In order to keep this low, the conveying element consists of a material which has essentially the same density as the conveying medium.

In the exemplary embodiment according to FIG. 9, the centrifugal pump is designed as a twin pump with a common drive 39. The arrangement of the sealing elements 40 and 41 corresponds to that shown in FIG. 7.

The two conveyor elements 42 and 43, offset by an angle of 180 ^* , as shown in FIG. 9, compensate for the static imbalance caused by the arrangement of the conveyor elements. With a correspondingly different choice of the angle, it is also possible to constructively compensate for dynamic imbalance in a simple manner with suitable counterweights, the pumping behavior of the pumps being independent of the angle. Weight compensation is preferably achieved by using the shapes of conveying elements shown in FIG. 3, which allow a changed mass distribution due to their deviation from the spherical shape.

For the use of the twin blood pump as a double bypass pump or as a complete heart replacement, it is important that the same blood volume flow is conveyed by the two pumps at a matching speed but different back pressures, which is achieved by a corresponding design of the Pump and its delivery characteristic is reached. FIG. 10 shows an embodiment of the centrifugal pump according to the invention for use as a blood pump, which is shown broken down into a reusable part 44 and a part 45 that can be used once. It can be seen that the pump upper part forming the one-time use part can be snap-connected to the part containing the drive motor 46 along the dividing line A, the necessary seal being produced by a circumferential sealing ring 47. It is thus possible, by simple handling after an operation in which the circulation had to be maintained by extracorporeal means, to design those parts as disposable articles which are cumbersome to clean and sterilize, or which parts are firmly are bound. In the example shown, the upper part 45 of the pump is permanently provided with hose lines 48 and 49, which at the same time establish the connection to adjacent components that can be used once.

In the pump according to the invention, it is possible to place the interface between parts that can be used once and repeatedly in the same way in such a favorable manner that the entire pump chamber that comes into contact with the patient's blood belongs to the parts that can be used once.

The interface, which forms the separation from the disposable article, expediently runs between the drive and rotation elements of the pump - in accordance with the principle that the dividing line is laid in such a way that all high-quality parts on the one hand and all parts that come into contact with the patient's blood on the other hand two separable units are combined.

OMPI Such an arrangement is shown with a dividing line B in the exemplary embodiment shown in FIG. 11. The single-use part 50 contains the closed pump chamber 50, the conveying element 51 also belonging to the single-use part.

The part containing the drive motor 52 and the support element 53 must be removed in a direction obliquely to the main axis due to the wobble movement to be generated by the drive. In order to facilitate this process, a cover part 54 can be removed from part 50, which covers a side region and the bottom region of the part receiving the motor. The part 54 can - according to the requirements - be designed both as a one-off and as a reusable part. It can be seen that the housing representations shown here are only examples and, in accordance with the further boundary conditions with the reusable motor, it is also expedient to combine those parts or components which are also used repeatedly in such a way that the pump chamber is connected is connected to the hose or connection system for the medium to be conveyed and the pump drive to further control devices or devices.

FIG. 12 shows an enlarged detail of a possible embodiment of the interface between a single and reusable part. Here, the carrying element 55 for the conveying element 56 of the pump chamber 57 is also one of the single-use elements. A hollow cone element 58 is firmly connected to the carrier pin 55,

OMPI which can be put over a corresponding conical projection 59 of the shaft 60 of the motor 61. This eliminates the need for separate storage for the conveyor element.

The pin 55 of the conveying element engages in a groove 62 of the cone during assembly, the drive motor 61 being able to be set into slow rotation if necessary for the assembly process. In order to achieve a “snap action”, additional permanent magnets 63 and 64 are provided on the conical part, which interact with a corresponding ferromagnetic region of the conical cap 58 and can absorb forces directed in the direction of arrow 65. The motor shaft 60 thus takes over the mounting of the rotating pump body, so that the pump chamber including the conveying element can be kept structurally simple. The pump body is centered and aligned with respect to the motor 61 by means of a collar 66 connected to the purape housing, the inner recess of which is adapted to the design of the motor 61.

FIG. 13 shows a twin pump which is used to supply a mass exchanger 67 which surrounds the drive motor 68 in a circle. Two pump chambers 69 and 70 are provided at the ends of the arrangement and each are designed as single-use units. The two pumps are connected in series, which results in an improvement in the hydrodynamic efficiency. The conveying elements 71 and 72 of the two pumps can be reused in the embodiment shown.

OMPI The substance exchanger is preferably used for dialysis or as an artificial lung in an e-corporeal circulatory system. In the case of the pumps shown, it should be noted in particular that in one case the inlet (lower pump) and in the other case the outflow opening (upper pump) are formed in a circular shape as an annular gap 73 and 74, so that the entire (correspondingly shaped) inlet - or outlet area of the mass exchanger is evenly supplied or disposed of. In the case of the centrifugal pump according to the invention, the fact is advantageously exploited that the flow conditions occurring - on average

- are rotationally symmetrical. (The twin pump shown can also be designed inexpensively in such a way that the two pumps are each placed on the mass exchanger with external drive motors, although two separate motors would be required

- The material exchanger itself can have a cylindrical full cross-section.)

In order to periodically control the speed of the pump in such a way that an at least approximately physiologically pulsatile flow is produced, timer means are preferably used which actuate the pump in pulses in time with the natural heart rate. These means are not shown in the drawings, but the components required for this are familiar to the person skilled in the art.

In order to assemble the conveying element from several materials or from one material or several materials and cavities in such a way that the average density of the conveying element is equal to or approximately equal to the density of the Is fluid and the conveying element including support element are dynamically balanced taking into account the fluid, tests can be carried out with suitable unbalance measuring means until the specified state is reached. In the illustrated embodiments, in addition to the provision of cavities, the dimensions of the conveying and carrying element can preferably be varied.

The embodiments shown are only preferred examples - the pump according to the invention can be used in many other applications and arrangements, the details of which are to be coordinated with the application, but can be developed by the person skilled in the art on the basis of the aforementioned exemplary embodiments.

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Claims

Patent claims

1. Hermetically encapsulated centrifugal pump for the gentle conveyance of fluids, in particular for the conveyance of blood, with a conveying element (9) which can move in a pump groove on a circular path and set the fluid in rotation,

characterized ,

that the conveyor element (12, 42, 43) fastened to a support element (6, 27, 36) executes a movement with a spatially fixed orientation in relation to the pump chamber (25),

that the support element forms a mechanical connection between a rotating drive element (3, 26) arranged outside the pump chamber and the conveying element and thereby performs a wobbling movement,

that the radius of the wobbling movement of the support element in a direction that runs parallel to the radius of the circular path in the passage area (8) of the support element through the wall of the pump chamber has a value that is smaller than the radius of the circular path, and

that a sealing element (15, 18) formed by an elastic membrane on the one hand with an area of the wall of the pump chamber surrounding the point of penetration of the support element and on the other hand with a circumferential

/ if a spatially fixed orientation in the area of the carrying and / or conveying element in the pump chamber is hermetically sealed.

2. Centrifugal pump according to claim 1, characterized in that _* the radius of the wobbling movement of the support element in said area (8) has an at least relative minimum.

3. Centrifugal pump according to one of claims 1 or 2, characterized in that the power transmission from the rotating drive element (3, 26) to the support element (6, 27) takes place eccentrically, the support element from the drive element in the direction of the extension of the axis of rotation of the drive element extends.

4. Centrifugal pump according to one of claims 1 or 2, d a d u r c h g e k e n n z e i c h n e t that the power transmission from the rotating drive element to the support element (36) takes place concentrically, the wobble movement being caused by a bend, inclination or kinking of the support element.

5. Centrifugal pump according to one of the preceding Ansprü¬ che, characterized in that a bearing (4, 5, 28) to compensate for a relative rotational movement between the drive element (3) and supporting or. Conveying element (6 or 9) is provided.

6. Centrifugal pump according to claim 5, that the bearing is oriented coaxially to an axis characteristic of the wobble movement, the supporting and / or conveying element being designed essentially rotationally symmetrical to this axis.

7. Centrifugal pump according to one of the preceding claims, so that at least the support element (6) for the delivery element (9) is enclosed by the sealing element (17).

8. A centrifugal pump according to claim 7, that the delivery element (9) is also enclosed by the sealing element (17).

9. Centrifugal pump according to one of the preceding claims, characterized in that the sealing element (15) has a casing (17) of the conveying element (9), a flexible sealing membrane (8) in the bearing area of the drive element and a lining ( 15) of the pump chamber as a coherently shaped membrane, which consists of a material that is matched to the fluid and durable with respect to alternating bending.

10. Centrifugal pump according to one of the. preceding Ansprü¬ che, characterized in that the flexible sealing element in the form of an inner lining closed except for the inflow and outflow opening in the manner of a coherent bag (18) into which the conveying element (9) is slipped and which encompasses the sealing area (8) between the support element and the pump housing.

11. Centrifugal pump according to one of the preceding claims for the promotion of blood, so that the sealing element (15, 18) consists of or is coated with a blood-compatible material.

12. Centrifugal pump according to one of the preceding claims, for the conveyance of blood, so that the housing (11, 16) of the implantable pump consists entirely of a blood-compatible material or is coated with such a material.

13. A centrifugal pump according to claim 12, which also means that the blood-compatible material is polyurethane.

14. A centrifugal pump according to one of the preceding claims, characterized in that the pump chamber comprising the circular path of the conveying element (9) is expanded in a funnel shape to an area which is adjacent to the mounting of the drive element.

15. Centrifugal pump according to one of the preceding An¬ claims _{"characterized} in that divided (16), the pump housing into an inflow port (14) and the outflow opening (13) exhibiting upper part (11) and a a passage for the drive member exhibiting Unter¬ part is .

16. Centrifugal pump according to one of the preceding Ansprü- before, characterized in that the conveying element (9) as a relation to the for the Taumelbe¬ movement characteristic axis (6) of the supporting element rota¬ tion symmetrical body is formed, wherein the portion _of, the housing ( 11), which forms a gap (19) with the conveyor element, is designed such that the gap shape is essentially independent of the position of the conveyor element on the circular path.

17. Centrifugal pump according to claim 16, so that the body is wholly or partially spherical, conical or ellipsoidal (Figures 3a to e).

18. Centrifugal pump according to one of the preceding Ansprü¬ che, characterized in that the conveying element is designed as an incomplete rotating body in such a way that when approaching the outflow opening, a maximum cross-section is directed transversely thereto (Figures 3a to e).

19. Centrifugal pump according to one of the preceding claims, that the center (23) of the circular path (22) on which the conveying element (9) moves is offset from the center (24) of the pump chamber (25).

20. Centrifugal pump according to claim 19, characterized in that the center point (23) of the circular path (22) is offset by a second angle relative to that axis of symmetry of the pump chamber (25) which is perpendicular to the outflow direction, that between the conveying element (9) and the edge last reached on its circular path (22) between the pump chamber and the outflow opening (13) is a minimum.

21. Centrifugal pump according to one of the preceding claims, characterized in that a cavity (29) is provided which accommodates at least the bearing for the drive (1) of the support element (27), which cavity is removed from the pump chamber by the sealing element is closed and filled with a liquid.

22. A centrifugal pump according to claim 21, characterized in that the cavity (29) through which in the wall provided inlet and outlet openings (32 and 33) is flowed through by a fluid which for cooling, lubricating and / or driving means forms.

23. Centrifugal pump according to claim 22, so that at least one of the openings (32 or 33) serves simultaneously as a passage opening for a cable connection (34) for an electric motor (1) for driving the conveying element (9).

24. A centrifugal pump according to one of the preceding claims, that the drive (1) for the conveying element (9) and the Purapraum are surrounded by a common housing (31).

25. Centrifugal pump according to one of the preceding claims, ie that the inflow opening (14) is arranged on the drive side of the conveying element in the pump chamber (FIG. 7).

26. Centrifugal pump according to one of the preceding claims, preferably for implantation in a living organism underneath a skin and / or tissue, since ¬ characterized in that the carrying element (26), the conveying element, and / or the drive element bearing body (3) mounted within the housing (31) and encapsulated hermetically in the pump housing and can be set in rotation by means of a magnetic field (37) rotating outside the housing.

27. Centrifugal pump according to one of the. preceding claims, d a d u r c h g e k e n n z e i c h n e t that the

OMH Pump housing with encapsulated magnet can be implanted in a living organism in such a way that the skin or tissue layer (38) surrounds the pump body (31) and the rotating magnetic field can be applied outside the body.

28. Centrifugal pump according to one of the preceding claims, d a d u r c h g e k e n e z e i c h n e t that the speed of the pump is periodically controlled so that an at least approximately physiologically pulsatile flow is caused.

29. Centrifugal pump according to one of the preceding claims, characterized in that the central axis of the outlet and / or inlet are curved in one plane or in space, in particular in such a way that the position of the inlet and outlet is an anatomically advantageous connection when used as Blood pump allows.

30. Centrifugal pump according to one of the preceding claims, d a d u r c h g e k e n n e e c h n e t that the support element is arranged in the pump chamber without independent storage, the bearing function being taken over by the motor shaft in the assembled state.

31. Centrifugal pump according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that

CMFI There is an easily detachable separation point (A, B and C) between the pump upper part and a support part containing the motor.

32. Centrifugal pump according to claim 31, that the separating point (A) cuts the pumping chamber with the exception of the conveying element.

33. Centrifugal pump according to claim 31, d a d u r c h g e k e n n z e i c h n t that the separation point (B) is provided outside the pump chamber and cuts the connection of the drive element to the motor axis.

34. Centrifugal pump according to one of the preceding claims, that the separating point (C) cuts a connecting element of the motor axis, which is designed in two parts in such a way that a centering element connected to the carrier element can be guided away with the pump chamber.

35. Centrifugal pump according to claim 34, that the centering element has an eccentrically arranged receptacle for the carrier element.

36. Centrifugal pump according to claim 35, characterized in that the centering element is held by means of adhesives.

37. The centrifugal pump according to claim 36, so that the adhesives consist of at least one permanent magnet (63, 64) which interacts with the centering device designed appropriately in this area by ferromagnetic means.

38. Centrifugal pump according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the

The centrifugal pump (69, 70) is designed as a twin pump with a solitary drive, by which the conveying elements (42, 43), which are offset by an angle with respect to one another, are driven at the same speed.

39. Centrifugal pump according to claim 38, so that the two conveying elements (42, 43) are arranged dynamically balanced together.

40. Centrifugal pump according to claims 30 to 39, d a - d u r c h g e k e n n z e i c h n e t that the two pumps (69, 70) are connected in series.

41. Centrifugal pump according to one of the preceding claims, for use in a mass transfer circuit, preferably for dialysis or for an artificial lung, that means that

CMFI the mass exchanger is connected to the inflow or outflow opening of at least one pump (73 or 74).

42. Centrifugal pump according to claim 41, so that the inlet or outlet opening connected to the material exchanger surrounds the Purapenkamraer at least partially in the form of an annular gap circumferentially.

43. A centrifugal pump according to claim 40, that the material exchanger at least partially surrounds at least one drive motor (68).

44. Centrifugal pump according to one of the preceding claims, characterized in that the conveying element is composed of several materials or of one material or several materials and cavities in such a way that the mean density of the conveying element is equal to or approximately the same as the density of the fluid and that Conveyor element including support element are dynamically balanced taking into account the fluid.

45. A method for producing a centrifugal pump according to claim 10, characterized in that the flexible sealing element as one except for the In and outflow opening closed inner lining in the form of a coherent bag (18) by briefly immersing a correspondingly shaped hollow body in an elastically hardening material in the liquid phase, so that only the mold is wetted, the hardened bag later being the Form is removed by everting through the inflow or outflow opening.

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