Implantable pump device for pumping bodily fluids

Abstract

An implantable pump device for pumping bodily fluids is known, comprising: a stroke-movable piston with a piston base; a wall portion facing the piston bottom in the stroke direction; and a pump volume enclosed between the piston bottom and the wall, the pump volume forming a section of a liquid path extending between the inlet and the outlet, where a stroke movement of the piston causes a change in the pump volume and thus a pump delivery of body fluid between the inlet and the outlet. According to the invention, the piston has a dimensionally stable disc section, the underside of which forms a piston base, and an elastic annular collar section, which protrudes radially from the disc section and is connected to the outer circumference of the disc section in a secure and fluid-tight manner at the inner circumference thereof, a dimensionally stable disc section is supported on the wall in a stroke-movable manner relative to the wall by means of an elastic annular collar section and is connected to the wall in a fluid-tight manner. The invention further relates to a method for manufacturing the disc section, in which the dimensionally stable disc section is supported on the wall in a stroke-movable manner relative to the wall by means of the elastic annular collar section and is connected to the wall in a fluid-tight manner.

Description

Technical Field

[0001] The present invention relates to an implantable pump device for pumping body fluids, comprising a piston with a piston bottom that can move in a stroke along a stroke axis, a wall portion that is arranged opposite to the piston bottom along the stroke axis, and a pump volume enclosed between the piston bottom and the wall portion, the pump volume forming a section of a liquid path extending between an inlet and an outlet, wherein the stroke movement of the piston causes a change in the pump volume and thus causes pumping of the body fluid between the inlet and the outlet. Background Art

[0002] Such implantable pump devices are known, for example, from US 9,731,101 B2. Known implantable pump devices are set up for pumping cerebrospinal fluid (CSF) from the cerebral ventricles of the brain into other cavities of the patient's body suitable for containing liquid. For this purpose, known implantable pump devices are implanted, for example, in the peritoneum and / or atrium, and are connected with the ventricles on the inlet side and with the cavity fluid-guided on the outlet side by means of a catheter suitable for this. Known implantable pump devices work according to the plunger principle and can be designed as peristaltic pumps, screw pumps, diaphragm pumps or piston pumps in particular. Piston pumps usually have a movable piston, a wall portion, and a pump volume enclosed between the piston bottom and the wall portion of the piston. The piston can move linearly with respect to the wall portion. Known, the stroke motion of the piston causes a change in the pump volume, which is accompanied by the pump delivery between the inlet and the outlet. In a common piston pump, the wall portion is designed as a cylinder. During the stroke movement, the piston slides frictionally in the interior of the cylinder (more precisely: along its cylinder inner wall). In order to seal between the piston and the cylinder inner wall, a piston sealing ring is usually used which is movably pressed against the cylinder inner wall. Summary of the invention

[0003] The object of the present invention is to provide an implantable pump device of the type mentioned at the outset which offers advantages over the prior art.

[0004] This object is solved in the following manner, that is, the piston has a disk section with stable shape and an elastic annular collar section, the lower side of which forms the piston bottom, wherein the annular collar section protrudes radially from the disk section, is firmly and fluid-tightly connected to the outer periphery of the disk section at its inner periphery, and is firmly and fluid-tightly connected to the wall at its outer periphery, whereby the disk section with stable shape is supported at the wall by means of the elastic annular collar section in a stroke-movable manner relative to the wall and is fluid-tightly connected to the wall. A simple structure and particularly stable function are achieved by the solution according to the invention. Along with this, the service life of the implantable pump device can be increased and its risk of failure can be reduced. This leads to improved patient safety. In addition, the simple structure allows cost-reduced production and simplified assembly. The above advantages are achieved by the design of the piston according to the invention and its interaction with the wall. The structure of the piston according to the invention is provided with a disk section with stable shape on the one hand, and an elastic annular collar section on the other hand. The disk section is mainly used as a plunger element of an implantable pump device that works according to the plunger principle. In particular for this purpose, the disk section is stable in shape. The shape stability allows the transmission of the force required for pumping body fluids. The annular collar section is mainly used for fluid-tight sealing of the disk section at the wall and support of the stroke movement. Therefore, the annular collar section obtains particularly advantageous multiple functions. This significantly contributes to the simplified structure and stable function of the implantable pump device. In order to support the disk section at the wall, the annular collar section is firmly connected to the disk section on the one hand, and firmly connected to the wall on the other hand. In order to achieve the required stroke movement of the piston despite the respectively firm connection, the annular collar section is elastically constructed. Therefore, the annular collar section is elastically deformed during the stroke movement of the piston. Due to the firm connection of the annular collar section at its inner circumference on the one hand and at its outer circumference on the other hand, no relative movement with respect to the disk section or the wall occurs at the said position. Friction losses are thus avoided. In order to seal the variable pump volume enclosed between the lower side of the disk section and the wall, the above-mentioned firm connection is also constructed in a fluid-tight manner between the inner circumference of the annular collar section and the outer circumference of the disk section on the one hand, and between the outer circumference of the annular collar section and the wall on the other hand. In this way, a separate sealing element can be omitted in particular. The firm and fluid-tight connection can be designed as a material-fit, form-fit and / or force-fit connection or constructed by means of one-piece continuous production. The shape-stable properties of the disk segment and the elastic and / or shape-yielding properties of the annular collar segment are achieved via corresponding dimensioning and / or material selection of the wall thickness. Preferably, the disk segment is thick-walled compared to the annular collar segment. Preferably, the annular collar segment is thin-walled compared to the disk segment. Preferably, the difference between the wall thicknesses is at least one order of magnitude, particularly preferably at least two orders of magnitude. Further preferably, the radial extension between the inner circumference and the outer circumference of the annular collar segment is at least 3 times, preferably at least 5 times, particularly preferably at least 10 times the wall thickness of the annular collar segment.In a preferred design, the radial extension of the annular collar section is 2mm to 6mm, particularly preferably 3mm. In a preferred design, the disc section has a diameter of 14mm to 20mm, particularly preferably 16mm. The fluid path of the implantable pump device has an inlet at one end and an outlet at the other end. The pump volume forms a section of the liquid path and is arranged between the inlet and the outlet in the delivery direction of the body fluid. The inlet and the outlet are fluidically connected to each other via the pump volume. In one design, a control element for controlling the pump delivery is arranged in the liquid path, which is preferably designed as a check valve. In another design, the implantable pump device does not have such a control element. Instead, the corresponding control element is, for example, placed in front of the inlet and / or placed at the outlet away from the implantable pump device, preferably in a fluid pipeline system that can be connected to the implantable pump device, etc. In a design, the implantable pump device has an actuator that is effectively connected to the piston to drive the stroke movement. The actuator is preferably effectively connected to the piston, especially the disc element, to transmit force and / or transmit movement. The effective connection can be mechanically and / or fluidly constructed. In principle, a magnetic operative connection is also conceivable. In another embodiment, the implantable pump device does not have such an actuator, wherein the actuator can instead be connectable to the implantable pump device, for example as a component of a separate drive device.

[0005] The implantable pump device according to the invention is particularly suitable for pumping body fluids, in particular cerebrospinal fluid. Of course, the solution according to the invention is also suitable for pumping medical fluids.

[0006] In the embodiment of the invention, the disk segment and the annular collar segment are formed in one piece and are continuous with each other. Due to the one-piece construction, the annular collar segment is firmly and fluid-tightly continuous with the outer circumference of the disk segment at its inner circumference, and vice versa. Therefore, a separate joint connection can be omitted. This leads to a further simplified structure and further improved stability. In this embodiment of the invention, the piston can be manufactured, for example, as a turned part, a cast part or a modified part. Alternatively, additive manufacturing is conceivable.

[0007] In a further embodiment of the invention, the disc segment and the annular collar segment are each made of metal, preferably titanium. The inventors have recognized that particular advantages can be achieved thereby. On the one hand, the production from metal, preferably titanium, results in biocompatible properties. On the other hand, advantages in manufacturing technology result. This applies to both multi-component and one-piece continuous production of the disc segment and the annular collar segment. Preferably, the wall is also made of metal, preferably titanium. In combination with the metal production of the annular collar segment, advantages in manufacturing technology result in particular. For example, the connection between the outer periphery of the annular collar segment and the wall can thereby be reliably securely and fluid-tightly constructed using simple means.

[0008] In a further embodiment of the invention, the outer circumference of the annular collar section is firmly and fluid-tightly joined to the wall by means of a material-fitting joint. In one embodiment, the material-fitting joint is an adhesive joint. In another embodiment, a welded joint is provided. This embodiment of the invention results in further advantages in terms of production technology. In addition, the structure of the implantable pump device is further simplified, since a separate connecting means for connecting the outer circumference of the annular collar section to the wall can be omitted.

[0009] In a further embodiment of the invention, the integrally bonded joint connection is a welded connection which is preferably produced without welding additives. In this case, the annular collar section and the wall are preferably each made of metal or weldable plastic. Compared to, for example, an adhesive bond, the welded connection offers improved biocompatibility properties. This is particularly true if the welded connection is produced without welding additives. In this case, the welded connection is, for example, laser welding, friction welding or resistance welding.

[0010] In a further embodiment of the invention, the wall thickness and / or shape of the annular collar section is designed in such a way that the elastic deformation of the annular collar section caused by the stroke causes a spring force that is opposite to the stroke movement, wherein the spring force causes or at least supports the complete resetting of the piston. Therefore, in this embodiment, the annular collar section additionally serves as a spring element for resetting the piston. As a result, separate components for resetting the piston can be omitted. At least these components can be designed to be less large. In other words, in this embodiment, the annular collar section preferably serves as a disc spring.

[0011] In another embodiment of the invention, the annular collar section has a flat shape. Thus, the annular collar section extends flat in the radial direction and / or in the circumferential direction. Such a flat design supports simple production. In addition, the flat shape simplifies the establishment of a firm and fluid-tight connection between the outer circumference of the annular collar section and the wall.

[0012] In a further embodiment of the invention, the annular collar segment has a wavy shape. The wavy shape is formed in the radial direction and / or in the circumferential direction of the annular collar segment. The annular collar segment preferably has a plurality of radial waves. In other words, the annular collar segment is provided with a plurality of waves in its radial extension, which waves extend continuously in the circumferential direction. The inventors have recognized that the wavy shape particularly supports the desired elastic deformation of the annular collar segment. This supports a smooth and thus well-supported and / or guided up and down movement of the disk segment connected to the annular collar segment.

[0013] In another embodiment of the invention, the wall has an additional elastic annular collar section, the outer periphery of which is firmly and fluid-tightly connected to the outer periphery of the elastic annular collar section of the piston. The additional annular collar section improves the deformation behavior of the annular collar section of the piston. The improved deformation behavior is accompanied by a particularly smooth stroke mobility of the disk section. This supports a particularly energy-efficient operation of the implantable pump device. Preferably, the additional annular collar section protrudes radially outward from a central section of the wall that is opposite the disk section. In this embodiment of the invention, the pump volume is preferably enclosed between the lower side of the disk section and the central section. The annular collar section of the disk element and the additional annular collar section of the wall are placed one on top of the other at their outer peripheries and are firmly and fluid-tightly connected to each other there. For this purpose, a material-fitting, shape-fitting and / or force-fitting connection is conceivable. A welded connection is preferred.

[0014] In a further embodiment of the invention, the annular collar section of the piston and the further annular collar section of the wall are arranged and / or designed mirror-symmetrically with respect to the radial center longitudinal plane of the pump volume. On the one hand, this mirror symmetry can provide advantages in terms of production technology. On the other hand, it results in a particularly advantageous elastic deformation behavior of the two annular collar sections and thus a particularly desirable stroke mobility of the disk section.

[0015] In another embodiment of the present invention, the liquid path has a first check valve and a second check valve, the first check valve being arranged between the inlet and the pump volume, the second check valve being arranged between the pump volume and the outlet and opening and closing in the opposite manner to the first check valve. The first check valve can also be referred to as an inlet valve. The second check valve can also be referred to as an outlet valve. Due to the structural form, the two check valves enable a particularly simple structure of the implantable pump device. In addition, a particularly robust and therefore less susceptible to interference control of the pump delivery of body fluids can be achieved. In another embodiment, an electronically controlled valve or the like is provided instead of the check valve.

[0016] In a further embodiment of the invention, the first non-return valve and / or the second non-return valve are integrated into the wall. This results in various structural advantages. On the one hand, compared to integration into the piston, it is in principle conceivable to achieve a reduction in the oscillating mass. On the other hand, the existing structural space can be better utilized. This enables a particularly compact structural shape of the implantable pump device.

[0017] The task on which the present invention is based is also solved in the following manner, that is, the section of the liquid path extending between the inlet and the pump volume is adjacent to the piston back side of the piston, which is opposite to the piston bottom along the stroke axis, so that the piston back side is pressure-loaded with the inlet side pressure of the body fluid. By the solution according to the present invention, it is realized to compensate for pressure fluctuations using extremely simple means. In the solution known from the prior art, the piston back side is encapsulated in a usual manner relative to the dominant ambient pressure. Therefore, the fluctuation of the ambient pressure acts on the body fluid of the patient and only acts on the piston bottom from there. In the implantable pump device known from the prior art, this may lead to an increased force requirement for the stroke movement of the piston. Accompanied by this, an increased energy consumption is generated, which is disadvantageous for various reasons. In the solution according to the present invention, the inlet side pressure of the body fluid (and therefore indirectly the ambient pressure) acts on the piston back side. Therefore, in order to pump body fluid, it is only necessary to overcome the dominant pressure difference between the pump volume and the outlet. This leads to a relatively smooth stroke movement and realizes the particularly energy-efficient operation of the implantable pump device. If the implantable pump device is implemented according to one of the above-described embodiments, the piston back side is the upper side of the dimensionally stable disk segment, which is opposite the lower side along the stroke axis. The section of the fluid path adjacent to the piston back side and / or the upper side of the disk segment can also be called a compensation chamber. During operation of the implantable pump device, the body fluid flows from the inlet through the compensation chamber, from there into the pump volume, and from this pump volume is further transported in the direction of the outlet. In other words, during operation of the implantable pump device, the compensation chamber is always flowed through by the body fluid. Stagnant liquid and the disadvantages associated therewith are thus avoided. In particular, accumulation at the piston back side and the resulting nucleation or other health-damaging phenomena are counteracted.

[0018] In a further embodiment of the invention, the implantable pump device has a housing having a first interior space, in which the piston, the wall and the liquid path are arranged, and a second interior space, which is sealed fluid-tightly relative to the environment and the first interior space and is designed to accommodate further components of the pump device. The further components can be, for example, an actuator for driving the stroke movement of the piston and / or a control device for controlling the actuator.

[0019] The invention also relates to an implantable device having a pump device according to any of the preceding claims. In one embodiment, the implantable device is a dialysis device for use in brain microdialysis, wherein the pump device is designed to pump cerebrospinal fluid. In another embodiment, the implantable device is used for pain therapy and / or for the treatment of spasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further features and advantages of the invention emerge from the claims and from the following description of preferred embodiments of the invention presented on the basis of the drawings.

[0021] Figure 1 A schematically greatly simplified sectional view of an embodiment of an implantable device according to the invention is shown, which is provided with an embodiment of an implantable pump device according to the invention,

[0022] Figure 2 The exploded perspective view shows the Figure 1 An implantable pump device,

[0023] Figure 3 The schematically greatly simplified cross-sectional view shows the Figure 1 and Figure 2 the piston, the wall and the pump volume enclosed between these components of the implantable pump device,

[0024] Figure 4 Shown according to Figure 3 A variation of the arrangement of

[0025] Figure 5 Shown according to Figure 3 Another variation of the arrangement of . DETAILED DESCRIPTION

[0026] according to Figure 1 , a pump device 1 implantable in a patient's body is provided for pumping body fluids.

[0027] exist Figure 1 In the embodiment shown in , the implantable pump device 1 is a component of an implantable device 100, which is schematically simplified. The implantable device 100 is currently provided for use in brain microdialysis. In this regard, the implantable pump device 1 is currently used to pump cerebrospinal fluid. Alternatively, the implantable device 100 can be used, for example, in pain therapy and / or for treating spasms.

[0028] The implantable pump device 1 (hereinafter referred to as: pump device) comprises a piston 2 with a piston bottom 3 which can be moved along a stroke axis H, a wall 4 which is opposite to the piston bottom 3 along the stroke axis H, and a pump volume V enclosed between the piston bottom 3 and the wall 4 (see also Figure 3 The pump volume V forms a section of the fluid path F extending between the inlet E and the outlet A of the pump device 1. A linear stroke movement of the piston 2 along the stroke axis H causes a change in the pump volume V and thus a pumping of the body fluid between the inlet E and the outlet A. Figure 1 In the case of a downward movement of the piston 2 (of the drawing plane), the pump volume V decreases. In the case of an upward movement of the piston 2, the pump volume V increases. The upward movement causes the body fluid to be sucked into the pump volume V. The downward movement causes the body fluid to be discharged from the pump volume V.

[0029] In order to control the above-mentioned pump delivery along the fluid path F, the pump device 1 in the embodiment shown has a control element which is described in more detail.

[0030] The piston 2 has a disk segment 5 with stable shape and an elastic annular collar segment 6. The lower side 7 of the disk segment 5 facing the wall 4 along the stroke axis H forms the piston bottom 3. The elastic annular collar segment 6 protrudes outward from the disk segment 5 in the radial direction R. The annular collar segment 6 is continuously surrounded in the circumferential direction of the disk segment 5. The annular collar segment 6 has an inner circumference 8 and an outer circumference 10. The inner circumference 8 can also be called the inner ring edge or the inner ring edge. The outer circumference 10 can also be called the outer ring edge or the outer ring edge. The inner circumference 8 is firmly and fluid-tightly connected to the outer circumference 9 of the disk segment 5. The outer circumference 9 of the disk segment 5 can also be called the outer disk edge or the outer disk edge. The outer circumference 10 of the annular collar segment 6 is firmly and fluid-tightly connected to the wall 4. As a result, the disk segment 5 with stable shape is supported (indirectly) on the wall 4 along the stroke axis H linearly and movably relative to the wall 4 by means of the elastic annular collar segment 6. On the other hand, the dimensionally stable disk section 5 is (indirectly) connected to the wall 4 in a fluid-tight manner by means of the annular collar section 6 .

[0031] The radial extension between the inner circumference 8 and the outer circumference 10 of the annular collar segment 6 is significant, ie at least one order of magnitude greater than the axial extension and / or the wall thickness of the annular collar segment 6. In an embodiment not shown in the figures, the radial extension is at least 3 times the wall thickness.

[0032] In the case of pumping of body fluids, the dimensionally stable disk segment 5 moves linearly up and down along the stroke axis H. Due to its dimensionally stable design, the disk segment 5 does not undergo, or at least does not undergo, any elastic deformations worth mentioning. This ensures, in particular, that the pumping force required for pumping body fluids can be introduced into the disk segment 5 in a satisfactory manner and can be transmitted from the disk segment to the pump volume V. In contrast to the dimensionally stable disk segment 5, the annular collar segment 6 undergoes elastic deformations during the stroke movement. In the case of a downward movement of the piston 2 and therefore of the disk segment 5, the annular collar segment 6 deforms elastically at its inner circumference 8 in the direction of the wall 4 along the stroke axis H. The outer circumference 10 remains immovable relative to the wall 4. The elastic deformability of the annular collar segment 6 ensures that the disk segment 5 can move linearly up and down along the stroke axis H. The fluid-tight connection at the inner circumference 8 and the outer circumference 10 ensures a reliable, fluid-tight seal between the piston 2 on the one hand and the wall 4 on the other hand. In other words, the annular collar section 6 serves, on the one hand, as a bearing and / or supporting element and, on the other hand, as a sealing element.

[0033] In order to achieve the desired elastic deformability of the annular collar section 6, in the embodiment shown, the annular collar section has a smaller wall thickness, which is described in more detail, than the disk section 5. In other words, the disk section 5 is thick-walled compared to the annular collar section 6. In contrast, the annular collar section 6 is thin-walled compared to the disk section 5.

[0034] In the embodiment shown, the disk segment 5 has a flat cylindrical outer shape (with respect to the stroke axis H). The outer circumference 9 of the disk segment 5 is therefore round or circular. The annular collar segment 6 protruding radially outward from the disk segment 5 has a circular outer shape in the embodiment shown. On the one hand, such a circular outer shape of the disk segment 5 and the annular collar segment 6 is not absolutely necessary. In an embodiment not shown in the drawing, the disk segment 5 and the annular collar segment 6 are instead each designed to be oval.

[0035] In the embodiment shown, the disk segment 5 and the annular collar segment 6 are constructed in one piece and continuously with one another. Therefore, the disk segment 5 and the annular collar segment 6 are different segments of the same component. By constructing them in one piece and continuously with one another, a separate material-fitting, force-fitting and / or form-fitting joint connection between the inner circumference 8 of the annular collar segment 6 and the outer circumference 9 of the disk segment 5 can be omitted. This simplifies the structure and the production. In addition, the required mechanical and fluid-tight connection between the inner circumference 8 and the outer circumference 9 can be constructed particularly firmly and reliably.

[0036] Although the one-piece construction is particularly advantageous, it is not absolutely necessary for the implementation of the invention. Accordingly, in an embodiment not shown in the figures, a multi-part production of the piston is provided, wherein the disk section and the annular collar section are produced as separate components and then joined together at the inner and outer circumference in a fixed and fluid-tight manner by means of a joint connection suitable for this purpose.

[0037] In the embodiment shown, the disk segment and the annular collar segment are made of metal. In particular, they are made of titanium. The production of metal, in particular titanium, is accompanied by satisfactory biocompatibility.

[0038] In an embodiment not shown in the figures, biocompatible plastics are used instead of metal to produce the disk segment, the annular collar segment and / or the piston. Biocompatible plastics are known to those skilled in the art.

[0039] In the embodiment shown, the outer circumference 10 of the annular collar section 6 is firmly and fluid-tightly joined to the wall 4 by means of a material-fitting joint 11. The material-fitting joint 11 is implemented differently in different embodiments. In the embodiment shown, the material-fitting joint 11 is a welded joint S.

[0040] Depending on the prevailing material choice, the welded connection S for the piston 2 and the wall 4 can be a metal or plastic welded connection.

[0041] In the embodiment shown, the wall 4 is also made of metal, in particular titanium. Accordingly, the welded connection S is a metallic welded connection.

[0042] In the embodiment shown, the welded connection S is produced without the use of welding additives. Further advantages are achieved as a result. Suitable welding methods for forming the welded connection S are, for example, laser welding, friction welding and / or resistance welding.

[0043] Further references Figure 3 , the wall thickness T and / or the shape G of the annular collar segment 6 are designed in such a way that the elastic deformation of the annular collar segment 6 caused by the stroke causes a spring force C that is opposite to the stroke movement, wherein the spring force C causes or at least supports the complete resetting of the piston. In the case of a downward movement of the piston 2, the annular collar segment 6 is elastically preloaded. The elastic preload of the annular collar segment 6 causes the spring force C. This spring force acts in the opposite direction to the downward movement of the piston 2. In other words: the elastically deformed annular collar segment 6 presses the dimensionally stable disk segment 5 back to its starting position along the stroke axis H. Depending on the dimensioning of the wall thickness T and the specific shape G, the resetting is either caused only by the elastic deformation or the spring force C, or is at least supported by the elastic deformation or the spring force C. At present, the latter is provided, wherein there is an (additional) spring element 12 for resetting the piston and is operatively connected to the piston 2 in a manner described in more detail (see Figure 1 ).

[0044] In the embodiment shown, the wall thickness T is 0.07 mm. In embodiments not shown in the figures, the wall thickness is between 0.04 mm and 0.15 mm.

[0045] The annular collar section 6 extends radially from its inner circumference 8 in the direction of its outer circumference 10. In the present case, this radial extension is 3 mm. In an embodiment not shown in the figures, the radial extension is between 2 mm and 6 mm.

[0046] In the present case, the annular collar section 6 extends radially at least substantially flat.

[0047] In the embodiment shown, the annular collar section 6 has an axial inclination, i.e. the inner periphery 8 and the outer periphery 10 are spaced apart from each other by an axial distance. In the embodiment shown, this axial distance is 0.3 mm. In an embodiment not shown in the figure, the axial distance is between 0.1 mm and 0.5 mm.

[0048] In the embodiment shown, the wall thickness of the dimensionally stable disk segment, which is not shown in more detail, is 1.5 mm. In an embodiment not shown in the figure, the wall thickness of the disk segment is between 1.0 mm and 5.0 mm. In addition, the disk segment 5 currently has a diameter of 16 mm. In an embodiment not shown in the figure, the diameter is between 14 mm and 20 mm.

[0049] In the present case, the elastic annular collar segment 6 has, in the region of its outer circumference 10 , an axial bundle 13 arranged along the stroke axis H. The axial bundle 13 simplifies the construction of the welded connection S. Furthermore, the axial bundle 13 supports the elastic deformation behavior of the annular collar segment 6 .

[0050] Further references Figure 3 In the present case, the shaping G of the annular collar section 6 is implemented flat in the radial direction R and in the circumferential direction. That is, there are no ridges, notches, waves, etc. on the annular collar section 6.

[0051] exist Figures 1 to 3 In the embodiment shown in , the wall 4 also has an elastic annular collar section 14. This is referred to as the additional annular collar section 14 below. The additional annular collar section 14 protrudes outward in the radial direction R and has an outer periphery 15. The outer periphery 15 of the additional annular collar section 14 is firmly and fluid-tightly connected to the outer periphery 10 of the elastic annular collar section 6 of the piston 2. Therefore, the joining connection 11 (more precisely: the welding connection S) is constructed between the outer periphery 10 of the annular collar section 6 of the piston 2 and the outer periphery 15 of the additional annular collar section 14 of the wall 4. Due to the additional elastic annular collar section 14, the wall 4 is elastically yielded in sections, that is, in the area of ​​the additional annular collar section 14. As a result, the disk segment 5 is supported during its stroke movement along the stroke axis H via a series connection of springs. The inventors have recognized that the presence of the additional annular collar section 14 is accompanied by different advantages. In particular, the required stroke mobility of the piston 2 is supported.

[0052] In the embodiment shown, the annular collar section 6 of the piston 2 and the further annular collar section 14 of the wall 4 are arranged and designed mirror-symmetrically with respect to the radial center longitudinal plane of the pump volume V. The wall 4 with its further annular collar section 14 can also be referred to as a further piston. This is due to the fact that the wall with its further annular collar section 14 is designed largely identically to the piston 2, wherein the main difference lies in the arrangement of the piston, which is movable on the one hand relative to the stroke axis H and fixed on the other hand relative to it (except for the further annular collar section 14). Therefore, the wall 4 can also be referred to as a fixed wall.

[0053] according to Figure 4 and Figure 5 Shown according to Figure 3Variants of the arrangement of . Only the main differences of the variants are discussed below. In addition, reference is made to the previously disclosed content.

[0054] According to Figure 4 According to the variant scheme of Figure 3 The additional annular collar section 14 is not absolutely necessary. Accordingly, the wall 4' there does not have such an annular collar section. Figure 4 The arrangement of the piston 2 and according to Figure 3 The same as piston 2.

[0055] according to Figure 5 Variations and bases Figure 4 The difference of the variant is the wavy shape G' of the annular collar segment 6'. The wavy shape G' of the annular collar segment 6' is accompanied by recesses 61 and ridges 62 extending in the axial direction. The recesses 61 and ridges 62 extend longitudinally continuously in the circumferential direction of the annular collar segment 6. Alternatively, it can also be said that the annular collar segment 6' has waves (more precisely: radial waves). The inventors have recognized that, in contrast to the embodiment according to Figure 4 Compared to the variant of , the corrugated shape G′ achieves improved stroke mobility of the disk segment 5 .

[0056] exist Figure 5 In the variant shown in the figure, the axial extension of the recess 61 and the ridge 62 is 0.4 mm in each case. This axial extension can also be referred to as the wave height of the wave-shaped profile G'. In a variant not shown in the figure, the axial extension (wave height) is between 0.2 mm and 0.8 mm. In the variant shown, the inner and outer circumferences of the annular collar segment 6' are axially spaced apart from each other by this wave height.

[0057] In the embodiment shown, check valves 16, 17 are present as the control elements already mentioned for controlling the pump delivery. Check valves 16, 17 are arranged in the liquid path F. Check valve 16 can also be referred to as a first check valve or inlet valve. Check valve 17 can also be referred to as a second check valve or outlet valve. The first check valve 16 is arranged between the inlet E and the pump volume V in the liquid path F. The second check valve 17 is arranged between the pump volume V and the outlet A in the liquid path F. The closing or opening directions of the two check valves 16, 17 are opposite to each other. The first check valve 16 opens in the case of an upward movement of the piston 2 and closes in the case of a downward movement of the piston 2. The second check valve 17 opens in the case of a downward movement of the piston 2 and closes in the case of an upward movement of the piston 2.

[0058] In the embodiment shown, two non-return valves 16, 17 are integrated into the wall 4. For this purpose, the wall 4 has a first receiving recess 18 and a second receiving recess 19. The receiving recesses 18, 19 are recessed into the wall 4 along the stroke axis H and are provided for receiving a respective one of the non-return valves 16, 17. The first receiving recess 18 receives the first non-return valve 16. The second receiving recess 19 receives the second non-return valve 17.

[0059] In an embodiment not shown in the figures, at least one of the two non-return valves is integrated into the piston 2. In another embodiment not shown, both non-return valves are integrated into the piston 2.

[0060] Further references Figure 1 It is shown that the liquid path F is guided in sections along the piston back side 20 of the piston 2 in the embodiment shown. In other words: the liquid path F has a section K directly adjacent to the piston back side 20 of the piston 2 (see Figure 1 ). The section K is arranged between the inlet E and the pump volume V. In the present case, the section K is also arranged upstream of the first non-return valve 16 in the flow direction. In the case of pumping of a body fluid, the body fluid flows from the inlet E along the liquid path F into the section K and from there further via the first non-return valve 16 into the pump volume V. The piston back side 20 is therefore loaded with pressure with the inlet-side pressure p of the body fluid to be pumped. In the embodiment shown, this pressure loading acts essentially on the entire surface of the piston back side 20, which in the present case also includes the outer side of the annular collar section 6 facing the section K. Due to the pressure p prevailing in the section K, the piston 2 is loaded with force along the stroke axis H in the direction of the wall 4. This force loading causes pressure compensation and enables particularly energy-efficient operation of the pump device 1, which will be explained in more detail below.

[0061] In the embodiment shown, the pump device has a housing 21. The housing 21 is subdivided into a lower half and an upper half. The subdivision is schematically shown according to Figure 2 With the help of the dashed lines there. The subdivision divides the overall interior space of the housing 21, which is not shown in more detail, into a first interior space 22 and a second interior space 23. The piston 2, the wall 4 and the liquid path F are arranged in the first interior space 22. The second interior space 23 is sealed fluid-tightly and / or pressure-tightly relative to the environment U and the first interior space 22. The second interior space 23 is used to accommodate further components of the pump device 1. For example, an actuator for driving the pumping movement of the piston 2 can be arranged in the second interior space 23. Alternatively or additionally, control electronics for controlling the actuator and / or the stroke movement can be arranged in the second interior space 23. Details in this regard are not mandatory for the implementation of the present invention, so that further elaboration is omitted.

[0062] In order to seal the second interior space 23 with respect to the environment U and the first interior space 22 in a fluid-tight and / or pressure-tight manner, a partition wall 24 is present in the illustrated embodiment. The partition wall 24 subdivides the entire interior space of the housing 21 into a lower half and an upper half or a first interior space 22 and a second interior space 23. At present, the partition wall 24 has a disc shape with a central through portion 25. The through portion 25 is used to axially pass a pin-shaped portion 28, which protrudes from the piston 2 in the axial direction upward from the piston back side 20, that is, in the direction of the second interior space 23. In the illustrated embodiment, the pin-shaped portion 28 is connected in one piece with the remaining sections of the piston 2. The pin-shaped portion 28 is established for effective connection with the transmission force and movement of the actuator. In other words, the pin-shaped portion 28 is used to introduce the pumping force into the piston 2. The pumping force is generated, for example, by the actuator described above and arranged in the second interior space 23. The pin-shaped portion 28 protrudes through the through-portion 25 in the axial direction and is sealed by means of a sealing disk 26. In the embodiment shown, the sealing disk 26 is made of metal (more precisely: titanium). In the present case, the sealing disk 26 has diaphragm elastic properties and can therefore also be referred to as a sealing diaphragm.

[0063] In accordance with Figure 1 In the illustrated assembled state, the pin 28 engages axially in a receiving bore (not shown in greater detail) of the pressure piece 27. The pressure piece 27 is used to exert the pumping force and is supported on the bottom side against the downward movement of the piston 2 by means of the spring element 12 on the top side (not shown in greater detail) of the partition wall 24. In this case, the spring element 12 is supported indirectly, namely via the sealing disk 26, on the partition wall.

[0064] according to Figure 1 It is known that the entire liquid path F is away from the second inner space 23 and extends separately from the second inner space 23. Due to the fluid-tight and / or pressure-tight packaging of the second inner space 23, it is not mandatory that the parts arranged there are biocompatible. On the contrary, the components and / or sections adjacent to the liquid path F can be implemented relatively simply and biocompatible. In the illustrated embodiment, the entire liquid path F or all components and / or sections adjacent to the liquid path F are biocompatible. At present, this biocompatibility is ensured by the corresponding material selection for the piston and the wall and the check valve.

[0065] In order to ensure that the piston back side 20 is in the upper end position of the piston 2 (as it is according to Figure 1 The piston 2 is also pressurized with the inlet-side fluid pressure p, and the piston 2 has a spacing section 29. The spacing section 29 abuts against the partition wall 24 (more precisely: on its underside) in the upper end position. The spacing section 29 causes the piston back side 20 to not abut directly against the partition wall 24, and the section K remains open for the pressure transmission to the piston back side 20.

[0066] In the embodiment shown, the downward movement of the piston 2 causes the discharge of body fluid from the pump volume V through the outlet A and the simultaneous suction of body fluid through the inlet E into the section K. In the case of an upward movement of the piston 2 , the body fluid first conveyed into the section K is further sucked into the pump volume V.

[0067] For example, when the patient's ambient pressure (atmospheric pressure) changes, the pressure compensation already explained above is advantageous. Such a change in ambient pressure will naturally also have an effect on the pressure of the body fluid. Its pressure corresponds to the ambient pressure. In some cases, significant pressure changes may occur, for example when traveling by plane. In the aircraft cabin, the pressure can be up to 400 mbar lower than on the ground. Therefore, a lower pressure is present on the inlet and outlet sides of the pump device and therefore also in the pump volume V. However, the pressure in the interior 23 remains constant because it is enclosed toward the outside. Therefore, a pressure difference occurs.

[0068] The effect of the pressure difference on the entire movable piston 2 will generate a force which makes it difficult for the piston 2 to return to the starting position of the piston 2. To counteract this, an increased return force can be provided by adapting the spring hardness of the piston 2 and / or the spring element 12. However, an increased return force in this way is disadvantageous under normal ambient pressure conditions. Because then a correspondingly increased pumping force must be applied, which leads to greater energy consumption.

[0069] In the present case, the forces resulting from the prevailing pressure difference are reduced in particular by using a partition wall 24 which divides the interior of the housing 21 into a constant pressure region 23 and a pressure adaptation region 22. The forces resulting from the pressure difference now act primarily on the surface of the sealing disk 26 and not on the entire piston 2. The required pumping force is therefore much less dependent on the ambient pressure, since this pressure is present on both sides of the piston 2.

Claims

1. An implantable pump device (1) for pumping body fluids, comprising: A piston (2, 2') with a piston bottom (3) which can move in a stroke along a stroke axis (H), A wall portion (4, 4') disposed opposite to the piston bottom (3) along the stroke axis (H) and having a pump volume (V) enclosed between the piston bottom (3) and the wall (4, 4'), the pump volume forming a section of a liquid path (F) extending between an inlet (E) and an outlet (A), in, The stroke movement of the piston (2, 2') causes a change in the pump volume (V) and thus causes the pumping of the body fluid between the inlet (E) and the outlet (A), It is characterized in that The piston (2, 2') comprises a dimensionally stable disk section (5) and an elastic annular collar section (6, 6'), the underside (7) of which forms the piston bottom (3), wherein the elastic annular collar section (6, 6') projects radially from the disk section (5) and is connected firmly and fluid-tightly to the outer circumference (9) of the disk section (5) at its inner circumference (8) and is connected firmly and fluid-tightly to the wall section (4) at its outer circumference (10), As a result, the dimensionally stable disk section (5) is supported on the wall (4, 4') by means of the elastic annular collar section (6, 6') so as to be movable relative to the wall and is connected to the wall in a fluid-tight manner.

2. The implantable pump device (1) according to claim 1, characterized in that The disk section (5) and the annular collar section (6, 6') are designed as one piece and are continuous with one another.

3. The implantable pump device (1) according to claim 1 or 2, characterized in that The disk segment (5) and the annular collar segment (6, 6') are each made of metal, preferably titanium.

4. The implantable pump device (1) according to any one of the preceding claims, characterized in that The outer circumference (10) of the annular collar section (6, 6') is joined to the wall (4, 4') in a fixed and fluid-tight manner by means of a material-bonded joint (11).

5. The implantable pump device (1) according to claim 4, characterized in that The integrally bonded joint (11) is a welded joint (S) which is preferably produced without welding additives.

6. Implantable pump device (1) according to any one of the preceding claims, characterized in that The wall thickness (T) and / or the shape (G, G') of the annular collar section (6, 6') causes a spring force (C) opposing the stroke movement, wherein the spring force (C) causes or at least supports a complete resetting of the piston (2, 2').

7. Implantable pump device (1) according to any one of the preceding claims, characterized in that The annular collar section (6) has a flat shape (G).

8. The implantable pump device (1) according to any one of claims 1 to 6, characterized in that The annular collar section (6') has a wavy shape (G').

9. Implantable pump device (1) according to any one of the preceding claims, characterized in that The wall (4) has a further elastic annular collar section (14), the outer circumference (15) of which is firmly and fluid-tightly connected to the outer circumference (10) of the elastic annular collar section (6, 6') of the piston (2, 2').

10. The implantable pump device (1) according to claim 9, characterized in that The annular collar section (6, 6') of the piston and the further annular collar section (14) of the wall (4) are arranged and / or designed in a mirror-symmetrical manner with respect to a radial center longitudinal plane of the pump volume (V).

11. Implantable pump device (1) according to any one of the preceding claims, characterized in that The liquid path (F) has a first check valve (16) and a second check valve (17), wherein the first check valve is arranged between the inlet (E) and the pump volume (V), and the second check valve (17) is arranged between the pump volume (V) and the outlet (A) and opens and closes in the opposite direction to the first check valve (16).

12. The implantable pump device (1) according to claim 11, characterized in that The first non-return valve (16) and / or the second non-return valve (17) are integrated into the wall portion (4, 4').

13. Implantable pump device (1) according to any of the preceding claims or according to the preamble of claim 1, characterized in that The section (K) of the fluid path (F) extending between the inlet (E) and the pump volume (V) adjoins the piston back side (20) of the piston (2, 2'), which is situated opposite the piston bottom (3) along the stroke axis (H), whereby the piston back side (20) is pressurized with the inlet-side pressure (p) of the body fluid.

14. The implantable pump device (1) according to claim 13, characterized in that A housing (21) having a first interior space (22) in which the piston (2, 2'), the wall (4, 4') and the liquid path (F) are arranged, and a second interior space (23) which is sealed fluid-tightly relative to the environment (U) and the first interior space (22) and is designed to accommodate further components of the pump device (1).

15. An implantable device (100) having a pump device (1) according to any one of the preceding claims.

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