DE19816120C1 - Blood pump, e.g. for a dialysis machine - Google Patents

Abstract

A blood pump comprises a pump housing (2), inlet and outlet bores, a blood advancing element which transports blood from the inlet through the housing to the outlet, and an external drive. A blood pump comprises a pump housing (2), inlet and outlet bores, a blood advancing element which transports blood from the inlet through the housing to the outlet, and an external drive. The housing (2) consists of a hollow member (1) which forms a closed loop. The blood advancing element has at least three independent piston elements. A holding zone (20) is formed between the inlet (3) and the outlet (5), and during deactivation the piston element is released.

Description

The invention relates to an extracorporeal blood pump according to the preamble of claim 1. Such blood pumps especially to promote blood through dialysis system or a heart-lung machine. Typi These applications typically require blood delivery gene from about 100 to 300 ml / min.

Extracorporeal blood pumps of this type are, for example from documents DE-C2-41 05 278, DE-C1-43 21 260 and DE-A1-44 30 853 known. It is blood pump like a centrifugal pump or a centrifuge galpump, and the blood delivery element forms one Rotor on which the blood-transporting wing is attached are shaped. The storage of the rotor or Impeller trouble because the blood the bearings not to contact. The entire pumping area housing with rotor and rotor bearing must be used only for single use disposable items be trained. Despite serial production, the costs are comparatively high.  

Alternatively, document DE-A1-39 35 502 discloses one encapsulated liquid pump, in particular for pumping of blood in a pump housing - instead of a Rotors - has a wobble body, which with the help of a non-contact magnetic drive in a wobble motion is set, which creates a variable gap and so the liquid promotes. Here too is the pump area housing with wobble body and membrane, which the blood from Self-aligning bearing separates, comparatively complex.

In contrast, it is much cheaper than pumps Housing squeezable hose of a roller pump. A typical roller pump is with two or three rollers equipped, which are moved along a circular path, in which the squeezable hose is inserted. Any role squeezes the pressure hose so far that its inner wall cuts come to lie on each other and the hose cross cut is closed. With the continuous movement the roll along the circular path becomes the one before every squeeze place the blood column through the inner tubing promoted. Such a "peristaltic" roller pump is characterized by a number of advantages. The one with an inlet port and an outlet port squeezable hose forms a simple and inexpensive producible component that easily fits into the pump body can be placed and after use against a fresh one squeezable hose can be replaced. Except there are no substantial changes from the pinch points cross-section of the blood column inside the tube on. This will result in considerable shear stresses and eddies and dead water zones within the blood column avoided. Ande on the other hand is disadvantageous in such a roller pump that Deformations and damage in the area of the pinch points the living cells of the blood, especially the erythrozy  echinocytes, spherrocytes and stomatocytes nen. Such deformations and damage to these cells can in turn result in hemolysis. Often ent the elastic tube material also holds plasticizers, and an abrasion of the hose material and / or an overflow of the Plasticizers in the blood can create an embolism hazard call.

With the document DE-A1-36 21 766 an "electromagnetic table pump ". One to promote blood proposed embodiment has a thick-walled, soft-plastic contractible hose in which Hose material a variety of individually controllable Electromagnets are used. Through a targeted approach Control of the electromagnet should he a contraction zone be witnessed by a fluid column in front of him Hose pushes. There is considerable realizability doubts. Also one that is electromagnetic squeezed tubing would damage living blood components.

The object of the invention is an extra corporal blood pump of the generic type ready make a similarly simple and inexpensive pump pen housing, like a roller pump, however Damage to living cells blood, hemolysis and risk of embolism.  

This task is the subject of Claim 1 solved.

The blood pump claimed clearly shows a be particularly simple pump housing, which at for example from a closed circular ring shaped tube, which is each with an adjacent Inlet and outlet is provided. The transport of the blood get through this tube simple piston elements, at for example balls made of steel or permanent magnetic Material that does not require any storage and / or guidance other. Such an annular tube can be easily in a Pump device are inserted, which with a Rota tion drive is equipped, the several permanent magnets or electromagnets on a circular circumferential path runs around the pipe wall. The pump housing can  made of inexpensive materials such as glass or biocompatible Plastic, such as polyethylene, polypropylene or poly urethane are manufactured. Inside the pump housing tre no significant cross-sectional changes and / or currents Direction changes on what turbulence, shear could cause stress or dead water zones; there is also a large amount within the pump housing uniform, comparatively low blood delivery rate efficiency. Valves are used to control the direction of blood flow not mandatory. The pump housing together with the col benelemente forms a simple and inexpensive to manufacture Disposable item that is discarded after one use that can.

The subclaims give execution types of Invention.

The intended pump housing consists of a hollow body which is provided with inlet and outlet and which is formed into a closed loop. Before preferably serves as a hollow body, a hollow cylinder, such as a tube or hose with a circular cross-section. The Pipe or hose can be made from a rigid, semi-rigid or plastic wall material. As wall materials come glass or plastics such as polyethylene, polypropylene or polyurethane into consideration. Preferably an anti hemolytic tubing selected, or a conventional Lich tube material is on its inner surface with a anti-hemolytic coating.

The hollow body forming the pump housing is one closed loop in which the Kolbenele elements continuously within the hollow body from the inlet to to the outlet and again to the inlet and outlet  etc. can circulate. This loop doesn't have to be more necessary be shaped like a ring; alternatively, one could oval or elliptical loop can be provided at for example if only along a hollow body section a forced drive of the piston elements is to take place. Preferably, however, the hollow body is a circular ring shaped loop. Inside an annular A rotary drive can be particularly easily pre-looped be seen, the permanent magnets or electromagnets along of the entire ring circumference of the hollow body.

On the hollow body formed into a closed loop is an inlet for the entry of blood and an outlet molded to the outlet of the blood. At this inlet you can it is a straight piece of pipe that has an inlet limited bore that sliding or grazing in enters the interior of the annular hollow body. In in the same way, the outlet can be a straight one Act pipe piece that delimits an outlet bore, the sliding or grazing as possible from the interior of the Hollow body emerges. For example, the one thus formed Enter the inlet nozzle from above into the ring plane, and the outlet nozzle thus formed can from the ring plane exit at the bottom. Typically the inside diameter is the Inlet bore and the outlet bore each smaller than that Diameter of the piston elements to prevent the col benelemente in the inlet bore and in the outlet bore to prevent. The inlet and outlet are as close as possible to each other, but at such a distance from each other arranges that the holding zone between inlet and outlet can be formed.

A conventional hose can be connected to the inlet through the drilling of the blood to be delivered  is created, and at the outlet a conventional Hose are connected, through the bore of which delivered blood to a dialysis machine or to a Heart-lung machine or the like is transported. Inner half of the hollow body the blood is along a conveying direction tion promoted, which leads from the inlet to the outlet.

The promotion of the blood is provided by piston elements that are non-contact with the help of magnetic coupling through the Interior of the hollow body are moved. These pistons elements consist of or contain a magnetic response material such as soft iron or cobalt or a permanent magnetic material, for example made of rare materials Earth elements with a particularly high coercive force. With With the help of magnetic coupling driven piston elements blood are forcibly transported through the interior of the hollow body. For this purpose, the piston elements should be possible shift as little friction within the hollow body Lich and on the other hand its cross-section essentially fill in to ensure good, predictable output to ensure. The piston elements can be rod-shaped Be made of soft plastic, in which powder Dispersed material made of magnetically attractive material is. Alternatively, the piston elements can be flexible substantial spherical body that is magnetically attached speaking liquid contained in an opaque casual plastic outer skin is included. Furthermore, these piston elements can be spherical body made of soft iron, steel, cobalt or made of a permanent magnet material with high coercivity force, such as how rare earth materials act. Additional Lich such balls with a biocompatible, ins special anti-hemolytic coating, for example be made of pyrolytic carbon. Preferably  such balls also have a polished surface. Such spherical bodies are particularly preferred because of jamming or jamming during the compulsion point out transport through the hollow body interior is closed.

During the operation of the blood pump, there is always a piston element held in the holding zone to the outlet from Separate inlet and so an undesirable blood flow between outlet and inlet. Hence are at least two piston elements within the hollow body available. Preferably three, four or five pistons elements provided. For example, two Piston elements using a rod-shaped, rotary driven arrangement adjusted within the hollow body be a permanent magnet on each end of the rod or has electromagnets. Alternatively, at the same time tig three piston elements with the help of a star-shaped arrangement can be adjusted at an angle of 120 ° each has a permanent magnet or electromagnet. To Another alternative can use four pistons at the same time elements adjusted using a crosswise arrangement be a permanent magnet at an angle of 90 ° each ten or has electromagnets.

These arrangements are made by a rotating drive driven that the permanent magnets or electromagnets run close to the wall of the hollow body. An electric motor is preferably used as the rotating drive intended. An electrical one is particularly preferred Stepper motor, because even at low revs speeds the speed of rotation and thus the position of the magnets can be precisely controlled.  

One is targeted in the space between the inlet and outlet deactivated deactivation zone, which - during their Activation - a piston element holds tight during the on drove the other piston element (s) through the Hollow body moves. The held piston element separates the outlet from the inlet, thus preventing unwanted Blood flow from the outlet to the inlet. During a desacti The crossing of the holding zone has so far been in the holding zone held piston element released and by a newly arriving piston element replaced by now reactivation of the holding zone is held. Provided the hollow body be made of an elastically resilient material stands, the targeted retention of a piston element by elastic deformation of a hollow body wall section are caused in the holding zone, which has a clamping effect exerts the piston element. Alternatively and preferably he follows the targeted retention of a piston element in the Holding zone with the help of an electromagnetic field, the by controlling an elec. provided with an iron core trical coil is generated. It is also possible in the Holding zone adjacent to each other two independently of one another to provide other controllable electromagnetic coils. The - with respect to the direction of conveyance - arranged downstream nete coil is activated to hold a piston element in the zone to hold on to while the other piston (s) element (s) circulate within the hollow body and blood transport. A circumferential piston element is approaching the holding zone, so becomes the second, upstream Coil additionally activated to this new piston element to hold on. Only after the presence of a Kolbenele mentes is detected in the upstream coil the other downstream coil is deactivated, and released the piston element held by it. On the downstream coil then closes again  activated and then the upstream coil of the activated to the piston element located in the holding zone release from the upstream coil and in the to hold downstream coil. With a sol Chen holding zone, which with two, independently controllable elec tromagnetic coils can safely turn off exchange of a newly arriving piston element for one to held piston element are carried out. To In addition, there may be sensors that arrive Detect a new piston element and remove the coil (s) control speaking. As such sensors can, for example wise Hall elements or reed contacts or inductance Changes detecting sensors are provided.

Preferably, the hollow body together with the ver slidably arranged piston elements as one for once disposable items designed for use, the easily inserted into and out of the further pump device this can be removed. The simple construction of the hollow body enables low production costs.

Exemplary embodiments of the invention are described below in detail explained with reference to the drawings; the latter demonstrate:

Fig. 1 with reference to a schematic drawing of the pump grundsätz union construction of the blood;

Fig. 2 based on a further schematic drawing of a first embodiment of the blood pump with a circular ring-shaped arrangement of the pump housing and three circumferential piston elements in the pump housing;

Fig. 3 is a schematic drawing of a second embodiment of the blood pump, which is equipped with four Kolbenelemen th;

Figure 4 is a schematic drawing of a third embodiment of the blood pump, which is equipped with a double-walled pump housing and with five piston elements. and

Fig. 5 shows a section of the pump housing with inlet and outlet and a holding zone with two elec tromagnetic coils.

The schematic drawing of FIG. 1 illustrates the Wesent union components of a blood pump according to the invention and their assignment. A formed as a closed loop ter hollow body 1 forms a pump housing 2. In this case, the closed loop has the shape of an oval. The pump housing is provided with an inlet 3 and an outlet 5 . At least two piston elements 7 and 7 'are arranged displaceably within the hollow body 1 and essentially fill the hollow body cross section. Each piston element 7 , 7 'contains or consists of magnetically speaking material. For example, the Kolbenele elements 7 , 7 'have a substantially rod-shaped shape and consist of a matrix of soft plastic, in the powdered magnetic material 8 high coercive force is dispersed. Outside of the pump housing 2 there is a drive 10 , which can adjoin a permanent magnet 11 at least for a distance and along the hollow body 1 in the direction of arrow A. In such a position of the permanent magnet 11 , the piston element 7 is correspondingly adjusted within the hollow body 1 in the conveying direction according to arrow B via magnetic coupling.

The inlet 3 is connected to a blood source (not shown). The outlet 5 is connected to a device (not shown) which is to be supplied with blood. After rich by suction or the like in the Einlaßbe a blood column within the hollow body 1 has been ausgebil, caused by the drive 10 adjustment of the piston element 7 within the hollow body 1 a promotion of the blood column in the direction of conveyance B to the outlet 5 .

Between inlet 3 and outlet 5 , a holding zone 20 is formed, which is provided with an electromagnetic coil 21 . Activation of this coil 21 generates an electromagnetic field, which is able to hold a second piston element 7 ′ via magnetic coupling in the region of the holding zone 20 within the hollow body 1 . Obviously, the second piston element 7 ′ held in the holding zone 20 separates the outlet 5 from the inlet 3 and thus prevents an undesired blood flow from the outlet 5 to the inlet 3.

After the first piston element 7 has been trans ported from the drive 10 or from the delivered blood flow into the region of the holding zone 20 , the coil 21 is deactivated. The second piston element 7 'held there can leave the Haltzo ne and enters the effective range of the drive 10. By reactivating the coil 21 , the newly arrived first piston element 7 is held in the holding zone 20 and separates the outlet 5 from the inlet 3 there . the ge promoted blood can escape only through the outlet 5.

The hollow body 1 with the piston elements 7 , 7 'located therein forms an independent component which can be easily inserted into the further pump device which realizes the drive 10 and the holding zone 20 and can be easily removed from it after use. The hollow body 1 with the Kol benelements 7 , 7 'is konzi piert as an inexpensive disposable item that should be discarded after a single use.

Fig. 2 shows a practical embodiment of a blood pump according to the scheme of Fig. 1. The hollow body 1 bil det here a closed loop in the form of a circular ring. This hollow body 1 consists of a cylindrical tube with a circular cross section. Glass and rigid or semi-rigid or moderately plastic orga nical plastics such as polyethylene, polypropylene and poly urethane come into consideration as tube material. From the hollow body 1 is each - in wesent union within the ring plane - an inlet 3 and an outlet 5 from. As an alternative to the embodiment shown, the inlet 3 could branch off tangentially from the circular ring and otherwise run parallel and above the ring plane, while the outlet likewise branches off tangentially from the circular ring and otherwise runs parallel and below the ring plane. The inlet 3 delimits an inlet bore and the outlet 5 delimits an outlet bore, each of which has a smaller bore diameter than the cross section of the hollow body.

Inside the hollow body 1 there are three steel balls 9 , 9 'and 9 "serving as piston elements, the ball diameter of which essentially fills the hollow cylinder inner cross-section, but which are displaceable within the hollow body 1. In the case of a non-contact adjustment via magnetic coupling these steel balls 9 , 9 'and 9 "are suitable for drawing blood from the inlet 3, conveying it through the hollow body 1 serving as the pump housing 2 and discharging it at the outlet 5 .

As a drive for adjusting the steel balls 9 , 9 ', 9 ", an electric stepping motor 12 is used , which allows a rod 13 to rotate, at the ends of which an electromagnet 14 , 14 ' is brought in. Excitation of the coils of the electromagnets 14 , 14th 'activation occurs on the current supply to the motor 12, 12 can these electric magnets 14, 14 of the stepping motor' along and migrate in close proximity to the inner circumference of the annular loop of the hollow body. 1 About magneti specific coupling takes each electromagnet 14, 14 'are each a steel ball 9 , 9 "with and moves it in the conveying direction B through the interior of the hollow body 1.

As long as the electromagnetic coil 21 is activated, a further steel ball 9 'is held in the holding zone 20 and separates the outlet 5 from the inlet 3 there. After the steel ball 9 guided by the electromagnet 14 has reached the area of the holding zone 20 , the electromagnetic coil 21 becomes deactivated briefly, whereby the originally firmly held steel ball 9 'is replaced by the newly arrived steel ball 9 . A renewed activation of the electromagnetic coil's 21 holds this steel ball 9 again in the holding zone 20 , while the magnet 14 'now moves the steel ball 9 ' through the interior of the hollow body 1 .

The embodiment according to FIG. 3 corresponds essentially to the embodiment according to Fig. 2. Notwithstanding allows the stepper motor 12 is a star-shaped assembly 15 rotate, the permanent magnet 19 of high coercive force is attached at its ends. The holding zone 20 is equipped with two electromagnetic coils 21 and 22 , the function of which is explained below with reference to FIG. 5.

The embodiment according to Fig. 4 corresponds to the embodiment of FIG substantially. 2. Notwithstanding makes the stepping motor 12 is a cruciform arrangement 16 of two rods 17 and 18 rotate at the rod ends a Per manentmagnet high coercivity 19 is mounted. In this case, five steel balls 9 are arranged within the hollow body 1 , each serving as a blood-promoting piston element. Each permanent magnet 19 is suitable for moving a steel ball 9 through the interior of the hollow body 1 via magnetic coupling. In this case, the hollow body 1 is provided with a double jacket arrangement 4 , and a thermostated liquid can be passed through the jacket gap in order to keep the blood conveyed through the pump housing 2 constant at a desired temperature.

The Fig. 5 is a schematic, fragmentary view of details of a preferred embodiment of the holding zone 20. In this case, two electromagnetic coils 21 and 22 in the specific regions of the holding zone 20 arranged. Each coil 21 , 22 consists of a winding and an iron core, which amplifies the electromagnetic field generated. After activation, each coil 21 , 22 can hold a piston element 7 ', in particular a steel ball 9 ', in the region of the holding zone 20 . In addition, there is at least one sensor 23 which detects the arrival of a circumferential piston element 7 or a circumferential steel ball 9 in the holding zone 20 . This sensor 23 can be a Hall element, a reed contact or an inductance change in the cross section of the hollow body 1 . The signal generated by the sensor 23 is used to control the electromagnetic coils 21 and 22 .

In typical operation, the downstream coil 21 is activated, holds a piston element 7 'or a steel ball 9 ' in the region of the holding zone 20 and thus separates the outlet 5 from the inlet 3. The sensor 23 detects the arrival of a newly arriving piston element 7 or a newly arriving steel ball 9 and activates the ge upstream coil 22 , which then additionally holds the newly arriving piston element 7 or the newly arriving steel ball 9 in the holding zone 20 . After such a holding of a second piston element 7 , or a second steel ball 9 within the holding zone 20 is carried out and detected, the downstream electromagnetic coil 21 is deactivated in order to release the piston element 7 'or the steel ball 9 ' held thereon that are then forcibly guided by the drive 10 or 12 through the hollow body 1 in order to convey blood towards the outlet 5 . Subsequently, the downstream ge placed coil 21 is activated and the upstream coil 22 deactivated to hold the newly arrived piston element 7 or the newly arrived steel ball 9 with the help of the downstream electromagnetic coil 21 in the region of the holding zone 20 . Such an exchange of a previously held piston element 7 'or a previously held steel ball 9 ' for a newly arriving piston element 7 or for a newly arriving steel ball 9 is repeated each time a piston element 7 or a steel ball 9 arrives.

The serving as a pump housing 2 hollow body 1 , which in its interior contains several, slidably arranged, serving as Blutför derelement serving piston elements 7 , 9 is designed as a disposable item designed for single use, which is easily built into and removed from a remaining pump device can be, which contains the drive 10 , 12 and the facilities of the holding zone 20 . The space requirement and the cost for the hollow body 1 can be compared with the corresponding expenditure for the replaceable hose of a roller pump.

Claims (16)

1. Extracorporeal blood pump, with

• 1. a pump housing which is provided with an inlet with an inlet bore and with an adjacent but spaced outlet with outlet boring,
• 2. a circulating in the pump housing Blutförderele element, which transports blood from the inlet through the pump housing to the outlet, and with
• 3. a drive located outside the pump housing, the movement of which is transmitted to the blood delivery element with the aid of magnetic coupling,

characterized in that
the pump housing ( 2 ) is a hollow body ( 1 ) which forms a closed loop;
the blood delivery element has at least two independent, within the hollow body ( 1 ) displaceable and its cross-section essentially filling Kol benelemente ( 7 , 7 '; 9 , 9 ', 9 ");
a deactivatable holding zone ( 20 ) is formed in the space between inlet ( 3 ) and outlet ( 5 ), which holds a piston element ( 7 ', 9 ') during its activation, while the drive ( 10 , 12 ) does one or the other ( n) piston element (s) ( 7 ; 9 , 9 ") moved by the hollow body ( 1 ); and
during a deactivation of the holding zone ( 20 ) the piston element ( 7 '; 9 '), which has been held for a long time, is released and replaced by a newly arriving piston element ( 7 ; 9 ), which is now held in place by renewed activation of the holding zone ( 20 ). 2. Blood pump according to claim 1, characterized in that the hollow body ( 1 ) forms a hollow cylinder with a circular cross section. 3. blood pump according to claim 2, characterized in that the hollow cylinder is a tube that is made of glass or a biocompatible plastic such as polyethylene, Polypropylene, polyurethane is made. 4. Blood pump according to claim 3, characterized in that the hollow cylinder has a double jacket arrangement ( 4 ), through the jacket gap of a thermostated liquid can be guided. 5. Blood pump according to one of claims 1 to 4, characterized in that the hollow body ( 1 ) is formed into a closed loop in the form of a circular ring. 6. Blood pump according to one of claims 1 to 5, characterized in that the piston elements are rod-shaped body ( 7 ) made of soft plastic, in the matrix of which a powdery permanent magnet material ( 8 ) having a high coercive force is dispersed. 7. blood pump according to one of claims 1 to 5, characterized in that the piston elements are plastic, spherical shaped bodies that are magnetically responsive Liquid inside an impermeable outer shell contain. 8. Blood pump according to one of claims 1 to 5, characterized in that the piston elements are spherical bodies ( 9 , 9 ', 9 ") made of soft iron, steel, cobalt or rare earth elements. 9. Blood pump according to claim 8, characterized in that the spherical body ( 9 , 9 , 9 ") are provided with a biocompatible, in particular anti-hemolytic coating. 10. Blood pump according to claim 8 or 9, characterized in that the spherical body ( 9 , 9 ', 9 ") have a polished surface. 11. Blood pump according to one of claims 1 to 10, characterized in that within the hollow body ( 1 ) three, four or five piston elements ( 7 , 7 '; 9 , 9 ', 9 ") are slidably arranged. 12. Blood pump according to one of claims 1 to 11, characterized in that the drive has an electric stepping motor ( 12 ) which drives a rod-shaped arrangement ( 13 ) or a star-shaped arrangement ( 15 ) or a cruciform arrangement ( 16 ), at the ends of an electric magnet ( 14 , 14 ') or a permanent magnet ( 19 ) is net angeord. 13. Blood pump according to one of claims 1 to 12, characterized in that in the holding zone ( 20 ) a piston element ( 7 '; 9 ') is held by means of an electromagnetic field which is generated by excitation of an electromagnetic coil ( 21 , 22 ) becomes. 14. Blood pump according to claim 13, characterized in that the holding zone ( 20 ) is equipped with two independently controllable electromagnetic coils ( 21 , 22 ). 15. Blood pump according to claim 13 or 14, characterized in that the holding zone ( 20 ) at least one sensor ( 23 ) is assigned, which the presence of a piston element ( 7 '; 9 ') in the holding zone ( 20 ) and / or that Arriving a new piston element ( 7 ; 9 ) at the holding zone ( 20 ) detected. 16. Blood pump according to one of claims 1 to 15, characterized in that the hollow body ( 1 ) together with the piston elements ( 7 , 7 '; 9 , 9 ', 9 ") arranged therein is designed as a disposable article designed for single use , which can be easily inserted into and removed from the other Pumpenvor direction.