Medical filter device and extracorporeal blood treatment device with a medical filter device

Abstract

The disclosure relates to a medical filter device (10), preferably a dialyzer or ultrafilter, comprising a housing (11), a plurality of hollow fibers (12) forming a fiber bundle (13) arranged in the housing (11), at least one connection (14) arranged on the housing (11) and designed to allow a fluid, preferably a dialysis fluid, to flow into the housing (11), in particular into a space (15) between the plurality of hollow fibers (12), and a cylindrical hollow body (16), in particular a diffuser ring, arranged within the housing (11) such that an annular channel (17) is formed between the cylindrical hollow body (16) and the housing (11) starting from the at least one connection (14), wherein the cylindrical hollow body (16) comprises the fiber bundle (13) and is arranged centrally in the housing (11).wherein the cylindrical hollow body (16) has at least one opening (19) on its outer surface (18) which has a cross-sectional area (20), wherein the at least one opening (19) is continuous, wherein the cross-sectional area (20) increases at least partially in the radial direction from the outside to the inside, so that the flow of the fluid slows down when flowing through the at least one opening (19). The disclosure further relates to an extracorporeal blood treatment device (30) with such a medical filter device (10).

Description

Technical field The present disclosure relates to a medical filter device and an extracorporeal blood treatment device with a medical filter device. Technical background Medical filters are generally known from the prior art. These filters are used, among other things, for purifying blood during dialysis, i.e., as dialyzers, or for filtering water, permeate, dialysis fluid, or replacement fluid. The filters can contain hollow fibers through which—in the case of a dialyzer—the blood flows. A fluid can flow around these hollow fibers. Through diffusion and / or convection processes across the hollow fiber wall, the blood can be purified. Hollow fibers are inherently fragile. A high flow velocity of the fluid flowing around them can damage the fibers. Furthermore, the aim is to achieve the most efficient and uniform blood filtration possible. This requires the most uniform possible flow around the hollow fibers. In this context, it has become apparent that there is a need to provide an improved medical filter device. Summary of the present disclosure It is therefore the purpose of the present disclosure to avoid or at least reduce the disadvantages of the prior art and, in particular, to provide an improved medical filter device. Specifically, it is the purpose of the present disclosure to provide a medical filter device that reduces or, if possible, avoids damage to the hollow fibers and that enables a uniform flow around the hollow fibers. The object of this disclosure is achieved by a medical filter device with the features of claim 1 and by an extracorporeal blood treatment device with the features of dependent claim 13. Advantageous embodiments are the subject of the dependent claims and / or are explained below. A first aspect of the present disclosure relates to a medical filter device, preferably a dialyzer or ultrafilter, comprising: a housing; a plurality of hollow fibers forming a fiber bundle arranged in the housing; at least one port arranged on the housing and designed to allow a fluid, preferably dialysis fluid or substitution fluid, to flow into the housing, in particular into a space between the plurality of hollow fibers; a cylindrical hollow body, in particular a diffuser ring, arranged within the housing such that an annular channel is formed between the cylindrical hollow body and the housing, starting from the at least one port; wherein the cylindrical hollow body encompasses the fiber bundle and is arranged centrally in the housing;wherein the cylindrical hollow body has at least one opening on its outer surface, which has a cross-sectional area; wherein the at least one opening is continuous; and wherein the cross-sectional area increases at least partially in a radial direction from the outside to the inside, so that the flow of the fluid slows down when flowing through the at least one opening. In this context, the term dialyzer refers specifically to a filter designed to filter a patient's blood by removing waste products and / or toxins. Blood and dialyzer fluid flow separately through a membrane (in this case, a hollow fiber). The waste products and / or toxins diffuse from the blood into the dialyzer fluid due to a concentration gradient. Fresh dialyzer fluid preferably enters the dialyzer via the aforementioned at least one port. Used dialyzer fluid or dialysate is preferably discharged from the dialyzer via another port. In this context, the term ultrafilter refers to a filter element designed to separate a liquid from particles, fungi, endotoxins, or similar substances by filtering the liquid through the membrane (in this case, a hollow fiber), in particular by allowing the liquid to pass from the space between the multitude of hollow fibers through pores into the interior of the hollow fibers, while the particles, fungi, endotoxins, or similar substances remain in the space between the multitude of hollow fibers. The term "housing" refers to a structural component that surrounds the fiber bundle and the cylindrical hollow body, providing a flow area for the fluid. The housing can be a single piece or multi-piece. It can be made of plastic or metal. The housing can have a cylindrical shape. It can include one or more ports for a fluid and / or a fluid to be filtered or a source fluid. In the case of a dialyzer, for example, these ports might include a dialyzer inlet, a dialyzer outlet, a blood inlet, and a blood outlet. The term hollow fiber refers to a tube with a semipermeable wall (i.e., a membrane). A fluid to be filtered, for example, blood in the case of a dialyzer, can flow through the hollow fiber(s). For instance, the blood flows through the hollow fiber(s) and is purified of waste products that diffuse through the wall of the hollow fiber(s). Alternatively, in the case of an ultrafilter, water, permeate, dialyze fluid, or substitution fluid can flow through the wall(s) of the hollow fiber(s), specifically through the pores of the wall(s). In this process, bacteria, particles, endotoxins, fungi, or similar substances larger than the pores are retained. In this way, the water / permeate / dialyze fluid / substitution fluid can be filtered. The term fiber bundle refers specifically to a multitude of hollow fibers. The fiber bundle can preferably be cast into the housing at two opposing end regions using polyurethane. This allows the individual hollow fibers to be fixed within the housing. An interface / connection for an inlet or outlet of a liquid to be filtered, for example, blood, can preferably be arranged above or below these end regions. In this context, the term connection refers to an interface to the inlet or outlet of a fluid. The term "cylindrical hollow body" refers to a structural component designed to enclose the fiber bundle and slow down the flow through its wall. The cylindrical hollow body can be a single piece or multiple pieces. It can be made of plastic or metal. The cylindrical hollow body can be, for example, positively bonded within the housing by means of polyurethane injection molding. It can also be arranged within the housing via a plug-in connection. The cylindrical hollow body can have a multitude of openings distributed across its surface, arranged in any desired pattern. The openings can differ in shape and / or dimensions. The cross-sectional area of ​​the opening preferably increases radially from the outside to the inside. The disclosure is based on the following insight: Filters, especially dialyzers, are dried with hot air after the fiber leak test (flowing water through the fibers). To speed up drying, hot air is used not only to penetrate the interior of the hollow fibers but also the space between them. Specifically, hot air enters the space between the hollow fibers via at least one connection, particularly the dialyze fluid connection. Strong turbulence is generated, especially in the area of ​​this connection, causing individual hollow fibers to vibrate. If the vibrations are too strong, the hollow fibers can break. Prior art has typically employed baffle plates to prevent the hot air or dialyze fluid flow from directly impacting the fiber bundle, or baffle rings to better distribute the dialyze fluid flow around the circumference of the fiber bundle.Neither the baffle plate nor the baffle ring reduces the turbulent flow itself, but merely relieves the fibers in the connection area by distributing the turbulent flow around the circumference of the fiber bundle. To solve these problems, the disclosure proposes a cylindrical hollow body, in particular a diffuser ring, which has openings with increasing cross-sectional areas. The cylindrical hollow body can thus advantageously distribute the flow uniformly around the circumference of the fiber bundle, reduce the turbulence by slowing the flow, and center the fiber bundle in the housing of the filter device.This allows for faster provision of the filter device after the fiber leak test, more efficient filtration during operation, and improved prevention of fiber damage both during the manufacture of the filter device and during its operation. In other words, the cylindrical hollow body, which is specifically designed as a diffuser ring, protects the fibers from highly turbulent flow on the dialysis fluid side and / or from highly turbulent hot air flow. A particularly uniform flow around the circumference of the fiber bundle is achieved through a corresponding distribution of openings, especially diffuser openings. During the manufacturing process, faster drying with hot air is possible. This particularly uniform flow allows for a reduction in fiber wall thickness and thus also increases filtration efficiency in a smaller space. According to a preferred embodiment, the at least one opening can comprise a plurality of openings distributed over a circumference of the cylindrical hollow body. The openings can be identical. The openings can be different. The openings can be evenly distributed around the circumference. The openings can be irregularly distributed around the circumference. In this way, a better flow around the fiber bundle can be advantageously enabled while simultaneously protecting the fragile hollow fibers. According to a preferred embodiment, the size of the cross-sectional area of ​​the plurality of openings can increase with an increasing distance of the respective opening from the at least one connection, so that a uniform flow of fluid through the plurality of openings is enabled over the circumference of the cylindrical hollow body. Near the connection, with identically sized openings, more fluid would flow through than through an opening located further downstream. Increasing the cross-sectional area of ​​the more distant openings reduces flow resistance. In this way, a uniform flow through the openings can be advantageously achieved. This uniform inflow can have a beneficial effect on the flow around the fiber bundle and thus on the efficiency of the filter / filter device. According to a preferred embodiment, the multitude of openings can be distributed in an axial direction of the cylindrical hollow body. In combination with the circumferential distribution of the openings, a planar opening pattern can thus be provided. This allows for both a targeted flow around the fiber bundle and a targeted reduction of the flow velocity in a synergistic manner. According to a preferred embodiment, at least one connection can be arranged in the axial direction of the filter device opposite the cylindrical hollow body, so that the flow of the fluid hits the cylindrical hollow body. In other words, at least one connection is located at the same height as the cylindrical hollow body. This eliminates unnecessary fluid paths, allowing for a compact device design. Furthermore, it reduces unnecessary flow losses, promoting efficient filter operation. According to a preferred embodiment, the cross-sectional area of ​​the at least one opening can comprise one or more of the following shapes: circular shape, oval shape, oblong shape, rectangular shape and square shape. Depending on the desired filtration performance and the surrounding system (e.g., extracorporeal blood treatment machine), different opening shapes may be more or less suitable. This allows the filter to be flexibly designed to meet the required flow characteristics, and the shape to be selected accordingly. Combined with a radially widening cross-section, this synergistically ensures optimized fluid flow and distribution. According to a preferred embodiment, the cylindrical hollow body can comprise plastic as the material. Plastics are characterized by low production costs. Furthermore, plastics are particularly suitable for medical applications. Shaping can be achieved efficiently using an injection mold and injection molding process. The plastic can be, for example, polypropylene or polyethylene. According to a preferred embodiment, the cylindrical hollow body can be connected to the housing by means of a casting process in a materially and / or form-fitting manner. The material-bonded connection via a casting process is already used to attach the fiber bundle within the housing. By appropriately designing the interface of the cylindrical hollow body, it can be cast in using the same casting process. For this purpose, the cylindrical hollow body is positioned inside the housing and, for example, polyurethane is cast in. This connection method is characterized by low costs. According to a preferred embodiment, the medical filter device can further comprise a second port, which is arranged on the housing and which is designed to allow the fluid to flow out of the housing. The at least one port is thus preferably a first port, which is arranged on the housing and which is designed to allow the fluid to flow into the housing. The second port can be identical to the first. It can also be different. The second port can allow for fluid recirculation. The fluid can flow out through the second port. In the case of drying air, the second port can be connected to the environment, allowing the drying air to escape easily. In the case of dialysate, the second port can be connected to a wastewater tank or a disposal interface, allowing used dialysate to be discharged into the wastewater tank or disposal interface via the second port. According to a preferred embodiment, the medical filter device may further comprise an inlet interface for an output fluid, for example blood, and an outlet interface for the filtered output fluid (the filtered blood). The inlet and outlet interfaces can preferably be connected to an extracorporeal blood circuit, in particular a tubing system, or an extracorporeal blood treatment device. The extracorporeal blood circuit can be designed or configured to be connected to a human being. According to a preferred embodiment, the starting fluid can comprise one of the following: blood, water, permeate, dialysis fluid, substitution fluid. It should be noted that the medical filter device can be used to filter blood as well as water / permeate / dialysis fluid / substitution fluid. This has a positive effect on the flexibility of use of the medical filter device. According to a preferred embodiment, the fluid may comprise one of the following: water, permeate, dialysis fluid, cold air, and heated drying air. In the manufacturing process, cold air is used to blow out the water before drying. Furthermore, cold air can be used in the microwave drying of medical filter devices. Another aspect of the present disclosure relates to an extracorporeal blood treatment device with a medical filter device as described above. The medical filter device can be used multiple times, i.e., at several points, in the extracorporeal blood treatment device, for example for filtering blood as a dialyzer and for filtering water / permeate / dialysis fluid / substitution fluid as an ultrafilter. The present disclosure is explained below with the aid of figures. These show: Fig. 1 a sectional view of a medical filter device according to the disclosure, Fig. 2 another sectional view of a medical filter device according to the disclosure, Fig. 3 a detail view of a sectional view of a medical filter device according to the disclosure, Fig. 4 an isometric view of a medical filter device according to the disclosure, Fig. 5 another sectional view of a medical filter device according to the disclosure, Fig. 6 another sectional view of a medical filter device according to the disclosure, and Fig. 7 an extracorporeal blood treatment device according to the disclosure. Fig. 1 shows a medical filter device 10 in a sectional view, showing only the upper half of the device. The lower half can be constructed identically to the upper half. The medical filter device 10 comprises a cylindrical housing 11. The housing 11 is made of a plastic material. Inside the housing 11 is a fiber bundle 13, which is formed from a plurality of hollow fibers 12. The fiber bundle 13 is connected to the housing 11 via a polyurethane casting section 22. The housing 11 is constructed in multiple parts. In this case, the housing 11 includes an intermediate housing element 23. The filter device 10 has a cylindrical hollow body 16. The cylindrical hollow body 16 is arranged inside the housing 11 and is also fixed via the polyurethane casting section 22. The filter device 10 has a connection 14 for a fluid.The fluid in this case is, for example, water, a dialysis fluid, or hot air. The filter device 10 further has an inlet interface 21 through which a source fluid, for example, blood, flows into the fiber bundle 13, in particular into the interior of the hollow fibers 12. The filter device 10 also has an outlet interface (not shown) for the filtered source fluid. The filter device 10 further has a second connection (not shown) for the outlet of the fluid. The fluid flows through the connection 14 and is slowed down by the cylindrical hollow body 16 and distributed evenly around the fiber bundle 13. For this purpose, the hollow body 16 has openings 19 that are evenly distributed over the outer surface 18 in the circumferential and axial directions. Fig. 2 shows another sectional view of a medical filter device 10 according to the disclosure. It can be seen that the fiber bundle 13 consists of individual hollow fibers 12. Spaces 15 are present between the hollow fibers 12, through which the fluid can flow. The blood can thus be purified by diffusion through the walls of the hollow fibers 12. The cylindrical hollow body 16 is arranged within the housing 11 such that an annular channel 17 is formed between the housing 11 and the cylindrical hollow body 16. Fig. 3 shows a detailed view of Fig. 2. Here it can be clearly seen that the cross-sectional area 20 of the openings 20 increases radially from the outside to the inside. This increase leads to a slowing of the flow and results in better distribution of the fluid as well as protection of the fragile hollow fibers 12. Fig. 4 shows an isometric view of a medical filter device 10. The openings 19 become larger with increasing distance from the connection 14. This allows for better distribution of the fluid. Fig. 5 shows another sectional view of a medical filter device 10. Here it can also be seen that the openings 19 increase in size with increasing distance from the connection 14 in order to allow a more uniform distribution of the fluid. Fig. 6 shows another sectional view of a medical filter device 10 according to the disclosure. In contrast to Fig. 1, the second connection 24 for the outlet of the fluid and the outlet interface 25 for the filtered output fluid can also be seen here. Fig. 7 shows a simplified representation of an extracorporeal blood treatment device 30 according to the disclosure. The extracorporeal blood treatment device 30 comprises a fluid source 31. The extracorporeal blood treatment device 30 includes two filter devices 33, 34, through which the fluid is filtered. The filter devices 33, 34 function as ultrafilters. The fluid filtered through filter device 33 is then used as the dialyze fluid. The fluid filtered through both filter devices 33, 34 is further used as a substitute via an interface 35 and directed into a substitute line 41. The once filtered fluid can, for example, be fed via interface 36 to a filter device 37, which functions as a dialyzer and is connected to a blood inlet line 39 and a blood outlet line 40.The fluid used, in particular dialysate, can be fed back into a disposal container 32 via an interface 38. The connecting lines represent lines. For clarity, pumps, heating elements, valves, controls, and the like have not been shown. Furthermore, for clarity, essentially only those elements of the extracorporeal blood treatment device 30 relevant to this disclosure have been shown. Reference symbol list 10 Medical filter device 11 Housing 12 Hollow fiber 13 Fiber bundle 14 Connection 15 Intermediate space 16 Cylindrical hollow body 17 Annular channel 18 Shell surface 19 Opening 20 Cross-sectional area 21 Inlet interface 22 PU casting area 23 Housing intermediate element 24 Second connection 25 Outlet interface 30 Blood treatment device 31 Source 32 Disposal container 33 Filter device, ultrafilter 34 Filter device, ultrafilter 35 Interface 36 Interface 37 Filter device, dialyzer 38 Interface 39 Blood inlet line 40 Blood outlet line

Claims

Medical filter device (10), preferably a dialyzer or ultrafilter, comprising a housing (11), a plurality of hollow fibers (12) forming a fiber bundle (13) arranged in the housing (11), at least one connection (14) arranged on the housing (11) and designed to allow a fluid, preferably dialysis fluid, to flow into the housing (11), in particular into a space (15) between the plurality of hollow fibers (12), a cylindrical hollow body (16), in particular a diffuser ring, arranged within the housing (11) such that an annular channel (17) is formed between the cylindrical hollow body (16) and the housing (11) starting from the at least one connection (14), wherein the cylindrical hollow body (16) comprises the fiber bundle (13) and arranges it centrally in the housing (11), wherein the cylindrical hollow body (16) has at least one opening (19) haswhich has a cross-sectional area (20), wherein at least one opening (19) is continuous, wherein the cross-sectional area (20) increases at least partially in a radial direction from the outside to the inside, so that the flow of the fluid slows down when flowing through the at least one opening (19). Medical filter device (10) according to claim 1, wherein the at least one opening (19) comprises a plurality of openings (19) distributed over a circumference of the cylindrical hollow body (16). Medical filter device (10) according to claim 2, wherein the size of the cross-sectional area (20) of the plurality of openings (19) increases with an increasing distance of the respective opening (19) from the at least one connection (14), so that a uniform flow through the plurality of openings (19) with the fluid over the circumference of the cylindrical hollow body (16) is enabled. Medical filter device (10) according to claim 2 or 3, wherein the plurality of openings (19) are distributed in an axial direction of the cylindrical hollow body (16). Medical filter device (10) according to one of the preceding claims, wherein the at least one connection (14) is arranged in the axial direction of the device (10) opposite the cylindrical hollow body (16), so that the flow of the fluid meets the cylindrical hollow body (16). Medical filter device (10) according to one of the preceding claims, wherein the cross-sectional area (20) of the at least one opening (19) comprises one or more of the following shapes: circular shape, oval shape, oblong shape, rectangular shape and square shape. Medical filter device (10) according to one of the preceding claims, wherein the cylindrical hollow body (16) comprises plastic as material. Medical filter device (10) according to one of the preceding claims, wherein the cylindrical hollow body (16) is connected to the housing (11) by a casting process in a materially and / or form-fitting manner, in particular cast into the housing (11). Medical filter device (10) according to one of the preceding claims, further comprising a second connection (24) which is arranged on the housing (11) and which is provided to allow the fluid to flow out of the housing (11). Medical filter device (10) according to one of the preceding claims, further comprising an inlet interface (21) for a source fluid and an outlet interface (25) for the filtered source fluid. Medical filter device (10) according to one of the preceding claims, wherein the starting fluid comprises one of the following: blood, water, permeate, dialysis fluid, substitution fluid, cold air, heated drying air. Medical filter device (10) according to one of the preceding claims, wherein the fluid comprises one of the following: water, permeate, dialysis fluid, substitution fluid and heated drying air. Extracorporeal blood treatment device (30) with a medical filter device (10) according to one of claims 1 to 12.

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