DE19857599A1 - Positive displacement pump preferably for use for medical purposes has fluid pumped by magnets that are driven by step motor - Google Patents

Abstract

A pump casing (1) has a pump chamber (2) circular in shape and round in section. The chamber has inlet (3) and outlet (4) openings and internal displacement elements (5). Magnets (13,14), driven by a step motor (10) through a gear train, move the displacement elements along the chamber so that it is divided into inlet and outlet zones of constantly changing size.

Description

The invention relates to a positive displacement pump arrangement for preferred use in medical areas, in essence Chen consisting of a pump vessel with an attached Inlet and outlet and a drive device with magnetic Power transmission to generate a fluid flow in the pump vessel.

Positive displacement pumps are used primarily in medical fields used as so-called extracorporeal blood pumps. In particular in cardiac surgery during open heart surgery the heart function must usually artificially over several hours Lich be replaced. To do this, blood pumps are used in conjunction with Membrane oxygenators used, the cardiac function and the Imitate and replace lung function.

Positive displacement pumps are available in different designs already known for example as roller pumps. One in one Ge The silicone tube inserted into the housing is rotated eccentrically Rolls stored in cash continuously milled. Blood promotion takes place quasi-continuously in the direction of movement of the rollers. The volume flow is determined by the choice of the hose diameter, the speed of the roller guide device and the degree of Adjustable hose squeeze.  

These pumps are characterized by simple application and low operating costs, but are in terms of hemoly blood problems. On the one hand, the occlusion leads the hose to a considerable shear stress of the Blood with the result that erythrocytes are crushed, on the other hand, it comes due to the considerable hay stress of the hose material for a migration of hose parts into the patient's bloodstream, like a broken shell. Already an operating time of about three hours means for the Pa increased risk.

U.S. Patent 5,800,138 discloses another tech African solution for an extracorporeal blood pump. Then be the pump consists of a cylindrical pump body that has an inlet and an outlet and inside two sail-like elements, which are mounted in the middle, arranged are not. These elements are arranged so that they the pump inside the body into an inlet and an outlet chamber divide. They are powered by a magnetic drive on a Orbit moves in such a way that always a sail-like element Separates inlet and outlet and the other towards the outlet is moved away and the liquid displaced.

The disadvantage of this solution is that the hermetic seal pump body thanks to the integrated rotating parts is complex and expensive that the axial bearing and the stän The rotational movement of both sail-like elements is harmful produce fabrics by abrasion on the bearing parts and tempera Differences in the inside of the pump vessel also lead to blood damage conditions due to the locally increased temperature load of the Blu due to frictional heat at the bearing points.

Another disadvantage is that the fluid-carrying parts the pump arrangement, particularly when used in medical African areas can only be used once in their Manufacturing is complex and costly.

It is therefore an object of the invention to provide a positive displacement pump  arrangement of the type mentioned to improve so that a Fluid, especially blood, as pollutant-free as possible and with low risk of haemolysis and the heart function can be replaced as naturally as possible and that especially the fluid-carrying parts of the arrangement are inexpensive producible and quick and easy to replace.

According to the invention the object is achieved in that the pump pen vessel with inlet and outlet opening from a ring-like pump pen chamber and at least one in the pump chamber Neten displacement element is that the pump vessel as a Component of the displacement pump arrangement is releasably assigned, that at least one magnet of the drive device the pump Pengefäß at least partially includes, circulates and controlled the at least one displacement element in the pumps chamber entrained so that the pump chamber in an inlet and an outlet area of constantly changing size separated becomes.

The displacement pump arrangement according to the invention enables a quick and uncomplicated replacement of the fluid guides the parts in particular through the design of the pump vessel with an integrated displacement element and thus firmly connected inlet and outlet opening as one component. The one fold design allows an inexpensive manufacture of the Pump container as a disposable product. The structure of the displacement Overall, the pump arrangement is structurally simple and safe to use. The fluid becomes gentle and pollutant-free transported, so that especially when transporting blood Risk of hemolysis is minimized.

According to a preferred and particularly inexpensive and structurally simple embodiment of the invention Arrangement, the pump chamber has a circular cross cut open and that is at least one displacement element arranged sealingly.

There are advantageously two in the pump chamber  Displacement elements arranged that are controlled in the pumps chamber are moved, one of the ver urging elements separate inlet and outlet while the other takes over the fluid transport.

A pulsating and therefore natural fluid transport achieved by changing the function of the displacement elements, by being in the phase of slow moving speed of a displacement element, which is in the sector between The outlet opening and inlet opening moved to very quickly len movement of the second displacement element between Inlet opening and outlet opening in the pump chamber comes and thus the liquid volume of the larger sector is pulsatile is expelled.

According to another preferred training of the fiction According solution, each displacement element has a cylindri form, consists of a magnetizable material and is covered with a biocompatible material.

This ensures that the displacement element, which un comes into direct contact with the fluid, despite magnetic Core consists of a biologically compatible material, so that fluid contamination is avoided.

From a constructive and cost perspective, this is an advantage if that Displacement element made of a permanent magnetic material is made.

Electromagnets are used to transmit external motion forces can also be used on the displacement elements, al However, the constructive structure of the Ver make the pump arrangement more complicated.

To prevent it in the pump chamber from becoming an unsafe if the fluid wants to come back, the displacement element must be ment be arranged sufficiently close in the pump chamber.  

This can be achieved in an advantageous manner by that the displacement element with at least one sealing element is provided, the cross section of the displacement element includes and form-fitting on the inner wall of the pump chamber is present.

The sealing element is ring-like around the displacement element ment arranged and form-fitting with the displacement element connected, made of a highly elastic material and lip-shaped.

Due to the design of the sealing element, the Circulation of the displacement element in the pump chamber minimizes friction.

If the lip-shaped sealing element to the inner wall of the pump Pen chamber is tapered to the point, this serves also minimizing sliding friction.

If each displacement element two spaced apart Has sealing elements, so is a high security non-clamping guidance of the displacement element and a back prevents the fluid from flowing, as a result of which the curvature radius of the pump chamber can be followed.

After a further advantageous training there is the pump pen chamber and the inlet and outlet arranged thereon from one biocompatible plastic or glassy material.

The use of the displacement pump arrangement is thus ins especially in medical fields.

To insert the displacement element into the pump To enable the inside, the pump chamber consists of two Half shells that are hermetically sealed after assembly are.

It is advantageous from a manufacturing point of view if the half-board  len are formed identically, that is, both both one half pump chamber as well as half inlet and outlet openings exhibit. This makes only one mold for both halves required, the manufacturing costs are minimized.

The hermetically sealed joining of both halves is ins particularly necessary for use in medical technology in order to to achieve closed system that is sterile before application is siert and with the germ-free or at least germ-free blood can be transported.

To prevent the displacement elements during the order run into or into the inlet or outlet opening tilt and thereby disrupt the proper pumping process, are different embodiments according to the invention seen.

According to an advantageous embodiment, the inputs and / or the outlet opening is formed like a grid, so that the Sealing elements in the entire interior of the pump chamber on the inner wall issue.

It is structurally easier to implement and less expensive to manufacture is another embodiment according to which the input and / or the outlet opening with at least one web-like element are equipped, at least partially through the opening protrudes.

The web-like element can be both vertical and protrude horizontally through the opening and also the opening completely divide into two parts. After this, too, it can be achieved that the sealing elements over the entire pump chamber on the inside wall concern.

Another embodiment is also possible, according to which Cross section of the inlet and / or outlet opening smaller than is the diameter of the displacement element.  

Even after this solution, the displacement is prevented element canted or gets stuck in the opening.

According to the invention it is further provided that the An Drive device from an electric motor drive, two with carrier arms firmly connected magnet pairs and a turn axis exists on which the support arms are mounted and the is connected to the drive.

This structurally simple embodiment ensures a safe function of the displacement pump arrangement and the on set of commercially available drive parts.

The magnet pairs are parallel above and below arranged half or to the side of the pump chamber and on each aligned a displacement element.

The symmetrical arrangement of the magnet pairs ensures ensures that the displacement elements evenly in the Pump chamber interior can be moved and the movement straight realized without axial rotation of the displacement element can be.

It is also advantageous if the axis of rotation is at the center of the arranged like a ring-shaped pump vessel is that the support arms are independent or optional are positively coupled.

Due to the arrangement of the axis of rotation in the center of the pump barrel, i.e. not within the pump chamber, is prevented that further pump parts come into contact with the fluid and can only be used once. Also be so temperature fluctuations in the pump chamber avoided, just as well as contamination of the fluid caused by abrasion in the pump pen drive arise.

To the intended movement of the two displacement To be able to easily implement elements is according to the invention  further provided that the axis of rotation as a double axis is formed that a support arm with an axle part is connected that one axis part projects through the other and that both axle parts via gear wheels of at least one Electric motor are driven.

This eliminates the need for complex mechanics to control the movement development process of the displacement elements. Both displacement elements can be moved independently, whereby the speed of movement can also be different. The forced coupling of both support arms is achieved that the axis of rotation is designed as a double axis, that each a support arm is connected to an axle part that an axle partly protrudes through the others and that both parts of the axis are over gears from an electric motor and intermediate planetary gears are driven.

The invention will be explained below with reference to a game Ausführungsbei. The associated drawing shows in Fig. 1, the displacement pump arrangement in a basic Dar position with pump vessel and electromotive drive arrangement,

Fig. 2 is a sectional view of the pump vessel in Prinzi pieller representation,

Fig. 3, a displacement element in sectional view,

Fig. 4 shows a cross section through the pump chamber in the region of the grid-like inlet or outlet opening and

Fig. 5 shows a cross section through the pump chamber in the region of the inlet or outlet opening, which has a web-like element.

According to FIGS. 1 and 2, the displacement pump arrangement is substantially out of the pump vessel 1 with the pump chamber 2, inlet orifice 3, outlet orifice 4, and two disposed therein, displacement elements 5, 6 and the electric motor drive device 7 with a dual axis of rotation 8, which gear wheels 9 with stepper motors 10 is connected and on which two support arms 11 , 12 are mounted, each of which carries a pair of magnets 13 , 14 . The magnet pairs 13 , 14 are arranged symmetrically around the pump vessel 1 and are each located above, below or next to a displacement element 5 , 6 .

The pump chamber 2 is annular and has a round cross section. Inlet and outlet opening 3 , 4 are formed directly on the pump chamber 2 and connected in one piece with the water. In order to enable the assembly of the displacement elements 5 , 6 in the pump chamber 2 , this consists of two identical half-shells, which are hermetically sealed after inserting the displacement elements 5 , 6 . This is possible, for example, by gluing both half-shells. The pump chamber 2 is made of a biologically compatible material, for example a plastic or a glass material.

Fig. 3 shows schematically a sectional view of a possi ble embodiment of a displacement element 5 , 6th The displacement elements 5 , 6 are then cylindrical and consist of a permanent magnet which is coated with a plastic or glass-like material suitable for medical use. They are adapted in shape and size to the inside of the pump chamber 2 and each have two spaced sealing elements 15 , in the form of sealing rings or sealing sleeves, which surround the displacement elements 5 , 6 in a form-fitting and fixed manner and lie sealingly against the inner wall of the pump chamber 2 . The sealing elements 15 are lip-shaped and tapered towards the wall of the pump chamber 2 . The resultant line support maintains the sealing effect, but the sliding friction generated by the circulation of the displacement elements 5 , 6 in the pump vessel 2 can be considerably minimized.

The displacement elements 5 , 6 are arranged so that a displacement element 6 separates inlet opening 3 and outlet opening 4 from each other. The other displacement element 5 , driven by the electromotive drive device 7, is guided from the inlet opening 3 to the outlet opening 4 , the fluid located in the larger sector of the pump chamber 2 being displaced in the direction of the outlet opening 4 .

When the displacement element 5 in motion has reached an angular position after passing through the outlet opening 4 and is located on the arc sector between the outlet opening 4 and the inlet opening 3 , the displacement element 6 is continued in the direction of movement so that after sliding over the position of the inlet opening 3 it takes over the pumping function . During the movement time of the displacement element 6 on the longer arc between inlet opening 3 and outlet opening 4 , the displacement element 5 takes over the shut-off function between the inlet and outlet openings 3 , 4 . By sliding the outlet opening in the direction of rotation through the displacement element 6 , the function change begins again, so that one of the displacement elements 5 , 6 constantly takes the flow barrier between the inlet and outlet opening 3 , 4 on the shorter circular arc before, while the other displacement element 6 , 5 for Pumping tasks are available. The inlet and outlet area in the pump chamber 2 is therefore constantly changed in size.

In order to prevent the displacement elements 5 , 6 from jamming in the inlet or outlet opening, it is seen in FIG. 2 that the inlet and outlet openings 3 , 4 have a smaller cross section than the displacement elements 5 , 6 . This ensures that at least one of the two sealing elements 15 is guided sealingly on the inner wall of the pump chamber 2 as it passes through the inlet and outlet openings 3 , 4 .

According to other embodiments shown in FIGS . 4 and 5, the inlet and outlet openings 3 , 4 are designed in a lattice-like manner or have a web-like element 16 in the form of a transverse web, which partially projects through the inlet and outlet openings 3 , 4 . Other designs, not shown in the drawing, are also possible, such as, for example, longitudinal webs or webs that divide the inlet and outlet openings 3 , 4 .

The movement sequence of the two displacement elements 5 , 6 is controlled by a controller that is connected to stepper motors 10 . Each stepper motor 10 is connected via gear wheels 9 , each with an axle part 17 or 18 of the double axis of rotation 8 , so that the support arms 11 , 12 can be driven independently of one another. An axis part 17 of the axis of rotation 8 is arranged in the other axis part 18 and on each axis part 17 , 18 a support arm 11 , 12 fitted with a pair of magnets 13 , 14 is fastened. The axis of rotation 8 is arranged in the center of the ring-like pump vessel 1 , so that it is ensured that the movement of the displacement elements by means of magnetically transmitted motive force accordingly the shape of the pump vessel on a circular path he follows.

The magnet pairs 13 , 14 are arranged symmetrically either above and below or to the side of the pump vessel 1 at intervals to prevent the displacement elements egg gene movements, which can occur due to the ripple of the pump chamber, and thereby increase the friction.

Reference list

1

Pump vessel

2nd

Pump chamber

3rd

Inlet opening

4th

Outlet opening

5

Displacement element

6

Displacement element

7

Electromotive drive device with magnetic power transmission

8th

Axis of rotation

9

Gear wheel

10th

Stepper motor

11

Support arm

12th

Support arm

13

Magnet pair

14

Magnet pair

15

Sealing element

16

web-like element

17th

Axle part

18th

Axle part

Claims (19)

1. displacement pump arrangement for preferred use in medical areas, consisting essentially of a pump vessel with an inlet and outlet arranged thereon and an electromotive drive device with magnetic transmission for generating a fluid flow in the pump vessel, characterized in that the pump vessel ( 1 ) with Inlet and outlet opening ( 3 , 4 ) consists of an annular pump chamber ( 2 ) and at least one in the pump chamber ( 2 ) on arranged displacement element ( 5 , 6 ) that the pump vessel ( 1 ) as a component of the displacement pump arrangement is releasably assigned that at least one magnet ( 13 , 14 ) of the electromotive drive device ( 7 ) at least partially encloses the pump vessel ( 1 ), rotates in a controlled manner and thereby carries the at least one displacement element ( 5 , 6 ) in the pump chamber ( 2 ) so that the pump Pen chamber ( 2 ) in an inlet and an outlet area constantly ver changing size is separated. 2. Displacement pump arrangement according to claim 1, characterized in that the pump chamber ( 2 ) has a circular cross section and the least least one displacement element ( 5 , 6 ) is sealingly arranged therein. 3. displacement pump arrangement according to claim 1 or 2, characterized in that in the pump chamber ( 2 ) two displacement elements ( 5 , 6 ) are arranged, which are moved in a controlled manner in the pump chamber ( 2 ), with one of the displacement elements ( 6 ) Separates inlet and outlet area ( 3 , 4 ), while the other ( 5 ) takes over the fluid transport. 4. displacement pump arrangement according to claim 1 and one of claims 2 or 3, characterized in that each displacement element ( 5 , 6 ) has a cylindrical shape, consists of a magnetizable material and is provided with a coating of a biocompatible material. 5. displacement pump arrangement according to claim 4, characterized in that the displacement element ( 5 , 6 ) is made of a permanent magnetic material Herge. 6. Displacement pump arrangement according to claim 1 and one of claims 2 to 5, characterized in that the displacement element ( 5 , 6 ) is provided with at least one sealing element ( 15 ) that includes the cross section of the displacement element ( 5 , 6 ) and seals the inner wall of the pump chamber ( 2 ). 7. displacement pump arrangement according to claim 1 and 6, characterized in that the sealing element ( 15 ) arranged in a ring around the displacement element ( 5 , 6 ) and is positively connected to the displacement element ( 5 , 6 ), consists of a highly elastic material and lip-shaped is trained. 8. displacement pump arrangement according to claim 6 and 7, characterized in that the lip pen-shaped sealing element ( 15 ) for the inner wall of the pump chamber ( 2 ) is formed tapering. 9. displacement pump arrangement according to claim 4 to 8, characterized in that each Ver displacement element ( 5 , 6 ) has two spaced sealing elements ( 15 ). 10. displacement pump arrangement according to claim 1 and one of claims 2 to 9, characterized in that the pump chamber ( 2 ) and the inlet and outlet opening ( 3 , 4 ) arranged thereon consists of a biocompatible plastic or glass-like material. 11. Displacement pump arrangement according to claim 1 and one of claims 2 to 10, characterized in that the pump chamber ( 2 ) consists of two half-shells, which are hermetically sealed after the assembly of the displacement elements ( 5 , 6 ). 12. Displacement pump arrangement according to claim 1 and one of claims 2 to 11, characterized in that the inlet and / or the outlet opening ( 3 , 4 ) are formed like a grid. 13. displacement pump arrangement according to claim 1 and one of claims 2 to 11, characterized in that the inlet and / or the outlet opening ( 3 , 4 ) with at least one web-like element ( 16 ) are permitted, which at least partially the opening ( 3 , 4 ) protrudes. 14. Displacement pump arrangement according to claim 1 and one of claims 2 to 11, characterized in that the cross section of the inlet and / or the outlet opening ( 3 , 4 ) is smaller than the diameter of the displacement element ( 5 , 6 ). 15. Displacement pump arrangement according to claim 1 and one of claims 2 to 14, characterized in that the electromotive drive device ( 7 ) from the drive ( 9 , 10 ), two with support arms ( 11 , 12 ) fixedly connected magnet pairs ( 13 , 14 ) and an axis of rotation ( 8 ) on which the support arms ( 11 , 12 ) are fastened and which is connected to the drive ( 9 , 10 ). 16. Displacement pump arrangement according to claim 1 and one of claims 2 to 15, characterized in that the magnet pairs ( 13 , 14 ) are arranged in parallel above and below or to the side of the pump chamber ( 2 ) and each have a displacement element ( 5 , 6 ) are aligned. 17. Displacement pump arrangement according to claim 1 and one of claims 2 to 16, characterized in that the axis of rotation ( 8 ) in the center of the ringar term pump vessel ( 1 ) is arranged and designed such that the support arms ( 11 , 12 ) independently or are positively coupled. 18. Displacement pump arrangement according to claim 17, characterized in that the axis of rotation ( 8 ) is designed as a double axis, that each Trä gerarm ( 11 , 12 ) with an axle part ( 17 , 18 ) is connected that an axle part ( 18 ) another ( 17 ) protrudes and that both axle parts ( 17 , 18 ) via gear wheels ( 9 ) by at least one stepper motor ( 10 ) are driven. 19. Displacement pump arrangement according to claim 17, characterized in that the axis of rotation ( 8 ) is designed as a double axis, that each Trä gerarm ( 11 , 12 ) with an axle part ( 17 , 18 ) is connected, that an axle part ( 18 ) projects through ( 17 ) and that both axle parts ( 17 , 18 ) are driven via gear wheels ( 9 ) by an electric motor and an intermediate planetary gear.