Pump housing with an interior for accommodating a pump rotor

Abstract

In a pump housing having an interior for accommodating a pump rotor, which may be transferred from a radially compressed state into a radially expanded state, and comprises a housing skin revolving in circumferential direction, as well as at least one reinforcement element, a stretch-resistant element revolving in circumferential direction is provided, which is stretched less than 5% in the expanded state as opposed to the force-free state in circumferential direction, and which limits any further expansion of the pump housing in radial direction.

Claims

1. A pump housing having an interior for accommodating a compressible and an expandable pump rotor, the pump housing comprising; a stretch-resistant, radially compressible pump housing skin extending in a circumferential direction, the pump housing skin formed of a stretch-resistant material, wherein a fully expanded housing skin defines a maximum expanded state of the pump housing; at least one reinforcement, the at least one reinforcement configured to expand in the circumferential direction along with expansion of the pump housing skin; and wherein the stretch-resistant material comprises at least one stretch-resistant fiber extending in the circumferential direction.

2. The pump housing according to claim 1, wherein the at least one stretch-resistant fiber is selected from the group consisting of glass fiber, carbon fiber, aramide fiber, and nylon fiber.

3. The pump housing according to claim 1, further comprising a vault or an arch formed by the at least one reinforcement when the pump housing is fully expanded, wherein the vault or arch resists forces directed radially toward the interior.

4. The pump housing according to claim 1, wherein the at least one reinforcement forms a surface-like, two-dimensional grate, which is bent in a form of a tube.

5. The pump housing according to claim 1, further comprising an interior wall limiting the pump housing interior, wherein the interior wall is cylindrical.

6. The pump housing according to claim 1, further comprising multiple reinforcements that are (i) pivotable against each other, (ii) form a tube shape in a first pivoting state, and (iii) are compressed radially as opposed to the tube shape in a second pivoting state.

7. The pump housing according to claim 1, wherein the at least one reinforcement is comprised of a super-elastic material selected from the group consisting of a super-elastic alloy and nitinol.

8. The pump housing according to claim 1, further comprising a valve within the pump housing at an axial distance to the pump rotor for changing a flow resistance for a fluid flow passing through the interior.

9. The pump housing according to claim 1, further comprising an interior wall limiting the pump housing interior, the interior wall tapering in an axial direction.

10. The pump housing according to claim 9, wherein the interior wall tapers in a conical manner.

11. The pump housing of claim 9, further comprising a rotor, the rotor having a cylindrical contour.

12. The pump housing of claim 9, further comprising a rotor, the rotor tapering in a direction that is the same as the axial direction in which the interior wall tapers.

13. The pump housing according to claim 12, wherein the rotor comprises a hub and at least one blade having a first end on the hub and a second end radially outward from the hub, wherein the second end and the interior of the pump housing form a gap therebetween, and wherein a size of the gap is 0.01 mm to 0.3 mm when the rotor is rotating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is shown based on an exemplary embodiment in a drawing, described in further detail below. They show:

(2) FIG. 1 a schematic illustration of a blood pump inserted into a heart chamber via a blood vessel;

(3) FIG. 2 a blood pump in a heart chamber at a longitudinal section,

(4) FIG. 3 a blood pump in a side view,

(5) FIG. 4 part of a pump housing with reinforcement elements,

(6) FIG. 5 a side view of a pump housing with reinforcement elements,

(7) FIG. 6 reinforcement elements for a pump housing in an expanded form,

(8) FIG. 7 the reinforcement elements of FIG. 6 in a compressed form,

(9) FIG. 8 a longitudinal section across part of a pump housing with a rotor, wherein the pump housing is embodied conically,

(10) FIG. 9 part of a longitudinal section of a pump housing with a rotor, wherein the housing interior is embodied cylindrically,

(11) FIG. 10 a schematic longitudinal section across a blood pump,

(12) FIG. 11 a longitudinal section across part of a pump housing with a reinforcement element,

(13) FIG. 12 a longitudinal section across a pump housing with circular reinforcement elements,

(14) FIG. 13 a longitudinal section across part of a blood pump with a pump housing, as well as a stretch-resistant element and reinforcement elements,

(15) FIG. 14 a longitudinal section across part of a blood pump with a valve downstream of the rotor,

(16) FIG. 15 a similar arrangement as in FIG. 14, with a valve upstream of the rotor,

(17) FIG. 16 an arrangement, wherein a rotor expels a fluid through a cage via a valve,

(18) FIG. 17 an embodiment of a valve in two positions, and

(19) FIG. 18 another embodiment of a valve in two positions.

DETAILED DESCRIPTION OF THE INVENTION

(20) FIG. 1 schematically shows a blood vessel 1 of a human body, which is connected to a heart chamber 3 via a heart valve 2, and into which a catheter 4 is inserted via a lock 5. The catheter 4 has a channel (lumen) in the interior thereof, via which a drive shaft 6 leads from an exterior drive motor 7 into a heart pump 8 inserted into the heart chamber 3. The heart pump 8 may be inserted into the blood vessel, for example, according to the known Seldinger technique, and advanced to the heart chamber through the same.

(21) The heart pump 8 has a rotor inside, which may be driven by a drive shaft 6 at several thousand, typically between 10,000 and 50,000, revolutions per minute, and transports blood in axial direction. The rotor is surrounded by a pump housing having a distal suction opening, via which the blood in the heart chamber 3 may be suctioned off.

(22) Such blood pumps are utilized for the replacement or supplementation of the natural heart function, either temporarily, or also permanently. Especially with the supplemental use of such a heart pump it is of advantage, if the natural activity of the heart remains uninfluenced such that the heart itself may also contribute to the pump function via the heart valve. For this purpose the heart may either provide supplementary pumping action through the pump, or bypassing the same, transport blood to the heart pump through the heart valve.

(23) FIG. 2 shows an embodiment of a heart pump having an approximately cylindrical pump housing 9 in an expanded form, containing a rotor 10. For example, the rotor 10 has a conveyor element helically revolving at a hub 11, in the form of a conveyor vane. The space occupied by the rotor during its rotation is cylindrical and matched to the housing interior of the housing 9 as accurately as possible.

(24) The pump housing 9 has a suction cage 12 at the distal end thereof, which is formed by several bracers simultaneously forming the reinforcement elements of the pump housing 9, which are embedded into the material of the pump housing, and axially project beyond the same in a distal direction.

(25) An atraumatic syringe 13 is disposed at the distal end of the suction cage 12, which has the shape of a ball 14 in the example, ensuring that the pump will not damage any vessel walls or heart walls while it is being inserted into the blood vessel and into the heart chamber, and that the suction end with the suction opening 12 of the pump housing 9 will not latch onto the vessel wall during the transport of blood.

(26) A film-like discharge jacket 16 is connected to the pump housing in a fluid tight manner in an axial area 15 of the pump housing. The discharge jacket 16 consists of a flexible, pliable, very thin film covering the discharge openings 17 of the pump housing 9, which are disposed on the side of the jacket, and reaches beyond these a little further in proximal direction of the pump, i.e. in the direction of the lock 5. The heart valve, schematically indicated by reference numeral 18, pushes the discharge jacket 16 against the expansion of the pump housing 9, and thereby closes the heart chamber opposite the blood vessel 1. When the pump is operated it will generate excess pressure and propels blood from the discharge openings 17 in radial and axial direction, which results in the discharge jacket 16 lifting up radially, and the opening of the heart valve 18 with sufficient pressure in order to allow blood into the blood vessel 1 past the proximal expansion of the pump housing 9 via the discharge jacket 16. This is the case particularly in that phase, in which the residual function of the heart being supported by the pump brings about an additional pressure increase in the inflow area of the pump. In this manner it is ensured that the blood flow from the heart chamber into the blood vessel is modulated with the chronological structure of the natural heart function.

(27) FIG. 3 shows in a side view another blood pump having a pump housing 9′, in which the cage-like reinforcement elements 20 are illustrated in the form of wire-like braces. The reinforcement elements 20 are continued at the distal end of the pump housing 9′ in free braces 21, 22, 23 into a suction cage, which allows the inflow of blood as indicated by the arrows 30, 31.

(28) The suction cage 21, 22, 23 further has a so-called pigtail 31 at the distal end thereof, which serves to prevent the latching on of the suction cage on a vessel wall.

(29) At the proximal end thereof, the pump housing 9′ has an ejection opening 32 at the front, from which the blood, indicated by arrow 33, may be ejected into a blood vessel.

(30) The proximal extension of the pump housing 9′ is formed by a catheter 4′, which has a hollow space in the interior thereof for accommodating a drive shaft for the pump.

(31) The pump housing 9′ is constructed with reinforcement elements 20 such that it may be radially well compressed together with the suction cage.

(32) The reinforcement elements 20 may, for example, be integrated into a pliable film, which forms the housing skin and is not stretchable such that it prevents an expansion of the pump housing 9′, after the expansion of the braces 20, beyond a firmly defined state.

(33) FIG. 4 shows in a side view a cylindrical section of a pump housing with inserted reinforcement elements 24, 25, which, revolving in circumferential direction, are configured in a meandering manner in case of the reinforcement element 24, and in the manner of a saw tooth in case of the reinforcement element 25. This form allows a simple radial expansion and compression of the housing. Additionally, reinforcement elements extending transversely to the same may also be provided.

(34) In FIG. 5 a reinforcement element 26 is schematically indicated, which is integrated in a housing 9″ as a compression spring. This reinforcement element 26 may also be compressed in a simple manner.

(35) FIG. 6 shows a plurality of circular rings 27, 28, which overall are formed into a tube, and may support a pump house in this manner, which is not illustrated.

(36) The circular rings may be pivoted against each other about an axis located in the drawing plane such that all are located in the same plane, as illustrated in FIG. 7. In this position the reinforcement elements 27, 28 are very strongly compressed in a radial direction (perpendicular to the drawing plane), while have unchanged measurements in radial direction perpendicular thereto.

(37) FIG. 8 illustrates a longitudinal section of part of a pump housing with a rotor, wherein the pump housing 9″ has a housing interior tapered conically at an acute angle. The cone angle is exaggerated in the figure to illustrate it better. Cone angles in a magnitude of a few degrees, in particular between 0.5° and 6°, further in particular smaller than 2°, are suitable as the cone angles. The exterior contour 15 of the rotor 10′, illustrated as a dotted line 35, is also embodied in a conical manner, that is to say advantageously with the same cone angle as the interior of the housing 9′.

(38) If the rotor 10′ is pulled into the narrowing area of the cone of the pump housing 9″, for example, by means of the drive shaft (not illustrated), the result is a fit between the exterior contour of the rotor 10′ and the interior wall 56 of the housing 9′″ that is become increasingly narrower. The rotor may be pulled until the optimum pump gap has been achieved.

(39) Contrary to FIG. 8, FIG. 9 shows an ideal cylindrical pump housing 9″ with an also cylindrical interior, in which a rotor 10″ is disposed, also having a cylindrical contour indicated by the dotted line 36. This configuration is insensitive to axial displacements of the rotor 10″ opposite of the housing 9″.

(40) Such constellation may also be utilized generally in rotor pumps independently of the idea of the main claim, that is to say the use of a stretch-resistant element for limiting the radial expansion of a pump housing.

(41) FIG. 10 schematically shows a longitudinal section of a pump housing 39 with a rotor 10′. The exterior contour of the rotor 10′″ is embodied in a cylindrical manner, and it is located in a cylindrical section of the housing 39. Reinforcement elements 29 are integrated into the housing wall of the housing 39 by means of casting, which are responsible for the expansion of the pump, and stretch the housing skin. A stretch-resistant element 37 in the form of an annular strip is illustrated, which radially surrounds the housing skin of the housing 39, thus effectively limiting the radial expansion of the pump housing 39. The reinforcement elements 29 are also still stretched in the expanded state of the pump at such a distance that they will react to any further expansion of the pump housing 39 with a certain excess force. This leads to the fact that a force acting radially from the exterior onto the pump housing 39 and does not exceed a magnitude of between 1 and 25 N, will not result in a radial compression of the housing 39.

(42) The stretch-resistant element 37 may be embodied, for example, as a high-strength plastic film, in particularly also with reinforcement fibers revolving in circumferential direction, e.g. made from or with glass fiber or carbon fiber materials, or also from or with aramide fibers or nylon fibers.

(43) The heart valve of the heart into which the pump is inserted, is indicated in FIG. 10 by the reference number 38. It is also shown that the pump housing 39 axially projects beyond the end of the rotor 10′ in distal direction, illustrated by a dotted line. The pump is positioned in the heart chamber such that the rotor 10′ is located outside of the heart chamber in a blood vessel, while part of the housing 39 projects distally from the dotted line 40 into the heart chamber. In the heart chamber itself the suction opening 41 is disposed, which is covered by a suction cage 42.

(44) The length of the housing extension of the housing 39 distally from the end 40 of the rotor up to the suction opening 41 may be between a few millimeters and several centimeters, such as between 0.5 and 10 cm, in particular between 0.5 and 5 cm, or 0.5 and 2 cm.

(45) FIG. 11 illustrates another structure of the pump housing 39′, in which a housing exterior skin 43 is directly equipped with reinforcement fibers revolving in circumferential direction such that the housing skin 44 itself forms the stretch-resistant element. A helical reinforcement element 45 is illustrated above the horizontal dotted line radially within the housing skin 44, which may be formed by a steel spring coil. However, the coil may also be formed by plastic, and integrally cast into the housing skin, as illustrated below the dotted line.

(46) FIG. 12 illustrates a pump housing 39″ consisting of a material that is inherently stretch-resistant, and which surrounds reinforcement elements 46, 47, 48, which are each individually embodied as circular rings. For the purpose of compressing the housing 39″ the individual circular rings may be collapsed at a sufficient force, or pivoted such that all circular rings in the cylindrical axis of the housing 39″ lie on top of each other in the same plane.

(47) FIG. 13 shows a constellation with a pump housing 39″, wherein the exterior skin 43′ of the housing consists of a stretchable membrane, and the reinforcement braces 39 positioned radially on the interior, and forming a structure, which are still elastically compressed for a short distance, even in the expanded state, and act upon further expansion of the housing, are retained by means of a stretch-resistant element 50 in tube form. The stretch-resistant element 50 is cylindrically shaped and has a dimension such that if it is stretched by the reinforcement elements 49, the housing skin 43′ is also correspondingly stretched. The elastic excess forces of the reinforcement elements 49 being embodied as a wire structure, have a dimension such that a radial force acting from the exterior onto the housing 39′, as long as it does not exceed 3 N, will not lead to a deformation of the housing 39′, and thus to a reduction of the diameter of the housing interior.

(48) At the distal end 51 thereof, the housing skin 43′ has a funnel-shaped extension 52, which facilitates the inflow of blood from the suction opening 53. Simultaneously, in case reinforcement elements are extending in the housing skin 43′ of the housing 39″, the same may axially run out from the funnel-type extension 52, and form a balloon-type suction cage. The exemplary reinforcement elements integrated in the wall of the housing 39′, are denoted by 54, 55.

(49) FIG. 14 shows in a side view analogous to FIG. 3 an additional blood pump. Furthermore, the rotor 10′ and proximally from the same, an additional valve 60 are illustrated, which prevent the backflow of the blood with the standstill of the pump, thus replacing the valve function in this manner, which is fulfilled in FIG. 2 by the discharge jacket 16 depicted therein, together with the heart valve 18. Here, the valve is embodied by means of multiple baffle-like, advantageously film-like sails, which open in the direction of arrow 61 under the flow pressure of the pump, and close again in case of a standstill of the pump. The sails may be embodied as one piece together with the housing skin, or may be attached to the same. Upon compressing the pump, the sails are also abutted at the wall of the housing, in order to ensure diameter reduction also in this area.

(50) FIG. 15 shows a blood pump analogous to FIG. 14, wherein the arrangement of the rotor and the valve is reversed. This arrangement is advantageous in that the drive shaft of the rotor does not extend within the valve.

(51) FIG. 16 shows a blood pump analogous to FIG. 15, wherein here, the flow direction of the blood is reversed. Such pumps, in which the blood flows from the proximal end of the housing, at which the catheter is attached, to the distal end of the housing, may be utilized advantageously, for example, for the support of the heart in the right cardiac ventricle.

(52) FIG. 17 shows in a longitudinal section, a pump housing 9′, as also in FIG. 18. Additionally, a rotor 10′″ is illustrated in FIG. 17. As an extension of the shaft 62 a stop body 63 is formed for the sails 64, 65 of a valve, at which the sails engage in case of a flow direction in the direction of arrow 66. In case of a flow direction in the direction of arrow 67, the sails being attached to the housing interior wall open the flow channel/the valve.

(53) FIG. 17 shows a stop body being tapered in the inflow direction.

(54) FIG. 18 shows a stop body having a cone 68 in the inflow direction, however, which is embodied in a flat manner on the discharge flow side thereof.

(55) The constellation illustrated herein may also be generally utilized in rotor pumps, in particular in compressible rotor pumps, as a function of the conditions of the main claim.