Method of packaging a bundle of hollow fiber membranes in a filter housing

Description

1 / 26 METHOD OF PACKAGING A BUNDLE OF HOLLOW FIBER MEMBRANES IN A FILTER HOUSING

[001] The present application relates to a method for potting the ends of a bundle of hollow fiber membranes into a filter housing with a potting mass, an apparatus for performing the method, a special potting cap for performing the method, a method for manufacturing a hollow fiber membrane filter and a hollow fiber membrane filter.

[002] Hollow fiber membrane filters are used in extracorporeal blood treatment of patients, water treatment, or biopharmaceutical processes. In the production of hollow fiber membrane filters, a bundle of hollow fiber membranes previously produced by a spinning and bundling process is inserted into a filter housing of a hollow fiber membrane filter. Cylindrical filter housings are commonly used as filter housing types. The ends of the hollow fiber membranes are potted into the end regions of the filter housing with a curable potting mass, usually polyurethane, and thus fixed to the housing. The end faces of the potting masses are then partially removed to expose the open ends of the hollow fiber membranes. Filter caps are then placed on the end sections of the filter housing.Two flow spaces are thus formed in the hollow fiber membrane filter. Two liquids can flow through the respective flow chambers and remain in mass transfer relation with each other through the membrane wall of the hollow fiber membranes. The respective liquids flow through the respective flow chambers by means of one liquid port in the filter cap and two liquid ports in the filter housing, or two liquid ports in the filter caps. In extracorporeal blood treatment, a first fluid, for example, patient blood, is drained into the fiber, and a second liquid, for example, dialysis fluid, is... Petition 870250089363, dated 10 / 01 / 2025, page 11 / 48 2 / 26 drained into the internal space surrounding the hollow fiber membranes.

[003] A crucial step in the manufacturing process of hollow fiber membrane filters is the potting of the ends of the hollow fiber membrane bundles into the filter housing. On the one hand, this process step is crucial for the productivity of hollow fiber membrane filter production. Many individual steps must be performed in this production stage, for example, fixing the filter housings in a potting system, injecting the curable potting mass into the end region of the filter housings, and curing the potting masses. Therefore, it is important that these production steps can be automated so that the production of hollow fiber membrane filters can be carried out efficiently on the large scale required.

[004] Furthermore, the potting of hollow fiber membrane bundles into filter housings also causes significant costs in the production of hollow fiber membrane filters. Usually, a potting mass that is able to flow at room temperature is used for potting the ends of hollow fiber membranes. Such potting masses are composed of several components, in particular pre-polymeric components. These components are designed to cure a resin within a certain time after mixing and according to a chemical reaction. Such curable potting masses suitable for the production of hollow fiber membrane filters are relatively expensive. Therefore, there are ongoing efforts to improve the industrial manufacturing process of hollow fiber membrane filters so that less potting mass is needed for safe potting of hollow fiber membranes in the hollow fiber membrane filter.

[005] Furthermore, heat-treated hollow fiber membrane filters, such as steam sterilization at 121 °C, evoke material stresses because the materials of the packing mass, filter housing, and hollow fiber membranes Petition 870250089363, dated 10 / 01 / 2025, page 12 / 48 3 / 26 have different coefficients of thermal expansion. Such material stresses can result in defective production, which must be detected and isolated in the industrial production process through appropriate quality control processes. Therefore, it is desirable to reduce such material stresses by reducing the contact of materials with different coefficients of thermal expansion in the hollow fiber membrane filter by using less potting mass.

[006] In common industrial processes, curable packing mass is injected into the end regions of filter housings, where the filter housing is rotated around an axis perpendicular to the longitudinal axis of the filter housings, and the curable packing mass is uniformly distributed in the end region of the filter housing between the hollow fiber membranes by means of centrifugal forces. The amount of curable packing mass required to economically pack a bundle of hollow fiber membranes in the end region of a hollow fiber membrane filter depends on several factors. Basically, the curable packing mass forms a meniscus in the rotation and distribution process of the curable packing mass in the end region of the filter housing. This means that the packing mass on the side facing the axis of rotation conforms to a concave-shaped surface.In the center of the hollow fiber membrane bundle, the potting height is thus smaller than in the lateral areas of the hollow fiber membrane bundle adjacent to the filter housing. Depending on the type of filter, the meniscus may be more or less pronounced. In the case of filters with a large number of hollow fiber membranes, it may consequently be necessary under certain process conditions to introduce a larger quantity of curable potting mass in the end region of the filter housing so that all the fibers in the center of the hollow fiber membrane bundle can also be safely embedded in the potting mass. The shape of the meniscus. Petition 870250089363, dated 10 / 01 / 2025, page 13 / 48 4 / 26 of the packing mass during rotation can also depend on other process conditions such as rotation speed, filter housing diameter and length. However, these process conditions cannot be optimized at will without sufficiently ensuring the desired distribution of the curable packing mass between the hollow fiber membranes and thus ensuring secure embedding of the hollow fiber membranes in the packing mass. In particular, if the packing density is increased to increase the filtration surface, secure embedding becomes more difficult because of the smaller packing volume then available between the hollow fibers.

[007] European patent EP 2 024 067 B1 describes a method for introducing a packing mass into a filter device having two flow spaces, of which a first space is formed by the tube passages of the fibers of a bundle of hollow fiber membranes and a second space is formed by a housing surrounding the bundle of hollow fiber membranes, the fiber end regions being fused into a packing mass after packing, and packing caps being fitted for the introduction of the packing mass. The packing mass is distributed from a packing chamber by means of the packing caps to the ends of the filter device, causing the packing chamber and the filter device to rotate.In this process, the filling mass is injected by means of centrifugal forces generated in such a way that, starting from the filling chamber and overcoming a gap between the filling chamber and the filling lid, the filling mass is guided to a rotationally symmetrical projection of the respective filling lid.

[008] The process principle described in EP 2 024 067 B1 is based on filter devices that have tabs at the ends of the housings. In this process, the injected curable filling mass flows between the tabs to the end region of the Petition 870250089363, dated 10 / 01 / 2025, page 14 / 48 5 / 26 hollow fiber membranes and spreads between the hollow fiber membranes to embed them in the potting mass. Although the process described in EP 2 024 067 B1 is eminently suitable for the production of hollow fiber membrane filters on a large industrial scale, this process is not suitable for reducing the required amount of curable potting mass. Objective of the Invention

[009] Based on the disadvantages present in the state of the art, there was consequently a need to optimize the process of filling hollow fiber membranes in a filter housing so that production costs and mechanical-thermal resistance of hollow fiber membrane filters could be improved. Summary of the Invention

[010] In a first aspect of the invention, the problem is solved by means of a method for enclosing the ends of a bundle of hollow fiber membranes in a filter housing, according to claim 1.

[011] In a second aspect of the invention, the problem is solved by means of an apparatus for packaging a bundle of hollow fiber membranes into a filter housing, according to claim 10.

[012] In a third aspect of the invention, the problem is solved by means of a filling cap, according to claim 12.

[013] In a fourth aspect of the invention, the problem is solved by means of a method of manufacturing a hollow fiber membrane filter, according to claim 13.

[014] In a fifth aspect of the invention, the problem is solved by means of a hollow fiber membrane filter, according to claim 14. Description of the Invention

[015] In a first aspect, the invention relates to a method for packing the ends of a bundle of hollow fiber membranes into a filter housing with a packing mass Petition 870250089363, dated 10 / 01 / 2025, page 15 / 48 6 / 26 comprising the steps of: insert a bundle of hollow fiber membranes into a filter housing that is open at both ends and has a longitudinal extension axis, which in particular is a tubular or cylindrical filter housing having a longitudinal extension axis, the filter housing having an inner side and an outer side, the filter housing having respectively at the two open ends an end region, each having a termination edge for the open end of the filter housing, wherein the hollow fiber membranes are inserted into the filter housing in such a way that the bundle of hollow fiber membranes forms an end face at the termination edge of the filter housing; place a potting cap on at least one end region of the filter housing, the potting cap comprising at least a first receiving portion to receive the end face of the hollow fiber membrane bundle and at least one end region of the filter housing, and comprising a suspended projection over at least one end region on the outside of the filter housing; Inject a curable filling mass into the projection of the filling cap in such a way that the curable filling mass flows between the outside of at least one end region of the filter housing and the filling cap; flow the curable potting mass over the termination edge of the first filter housing in such a way that the curable potting mass flows to the end face of the hollow fiber membrane bundle formed by the hollow fiber bundle; to encase the ends of the hollow fiber membranes of the hollow fiber membrane bundle in the filter housing; and to allow the encasement mass to cure, characterized in that the filter housing with the hollow fiber membrane bundle is rotated around an axis of rotation that is perpendicular to the longitudinal extension axis of the filter housing, such that Petition 870250089363, dated 10 / 01 / 2025, page 16 / 48 7 / 26 The overflow through the termination edge of the filter housing with the packing mass and the influx of packing mass to the end face of the hollow fiber membrane bundle are effected by centrifugal forces resulting from the rotation of the filter housing.

[016] The method has the advantage that the filling process can be automated. This is made possible in particular by the projection of the filling cap, which allows the curable filling mass to be injected into the filling cap without having to comply with rigid mounting tolerances that are difficult to implement, especially during rotation of the filter housing. Furthermore, the penetration of the curable filling mass between the fibers occurs from the direction of the end faces of the hollow fiber membrane bundle. The penetration of the composite curable mass between the hollow fiber membranes thus happens against the direction of the centrifugal forces acting due to the rotation of the filter housing with the hollow fiber membrane bundle arranged therein.The curable packing mass on the end faces of the hollow fiber membranes is compressed and thus distributed between the hollow fiber membranes by the subsequent influx of curable packing mass. The penetration of the curable packing mass from the end faces of the hollow fiber membranes against the prevailing centrifugal forces causes the meniscus depth of the curable packing mass in the end region of the filter housing to decrease. The “meniscus depth” is the difference between the packing height adjacent to the filter housing and the packing height at the center of the hollow fiber membrane bundle. According to the process, the packing mass is distributed more uniformly in the end region of the filter housing, which means that the packing height and thus the amount of packing mass required can be reduced without losing secure embedding of the hollow fiber membranes in the packing mass. Petition 870250089363, dated 10 / 01 / 2025, page 17 / 48 8 / 26 bottling.

[017] For the purposes of the present application, the term “hollow fiber membrane bundle” means a plurality of hollow fiber membranes that are adjacent substantially parallel to each other. The ends of the individual hollow fiber membranes are adjacent to each other in the hollow fiber membrane bundle.

[018] According to the present application, the filter housing has an elongated extension and in particular is tubular, or shaped in a cylindrical form.

[019] For the purposes of this application, the term “elongated dimension” means that an object has a dimension in one direction that is greater than in a direction perpendicular to it.

[020] In the context of the present application, the term “end region of a filter housing” means an end region in the filter housing extending in a longitudinal direction from the end of the filter housing to the center of the filter housing. The term “end region” indicates that it is a region in the filter housing that occupies only a small part compared to the longitudinal extent of the filter housing. In particular, each of these end regions is less than one-fifth, or less than one-eighth, or less than one-tenth, or less than one-fifteenth of the total length of the filter housing.

[021] A “termination edge” is understood to be a circumferential edge at the end of the filter housing.

[022] In the context of the present application, the “end face of the hollow fiber membrane bundle” is to be understood as an end face of the hollow fiber membrane bundle in which the ends of the hollow fiber membranes are substantially adjacent to each other. Such an end face can, for example, be generated by cutting the hollow fiber membrane bundle perpendicular to its longitudinal extent.

[023] In the context of the present application, “bottling cap Petition 870250089363, dated 10 / 01 / 2025, page 18 / 48 9 / 26 is to be understood as a cap that can be placed on the end region of the filter housing and thus covering the end face of the hollow fiber membrane bundle. In this case, the potting cap is designed so that the end region or part of the end region of the filter housing and the end face of the hollow fiber membrane bundle are received in a receiving portion of the potting cap.

[024] In the potting stage, the curable potting mass flows uniformly between the hollow fiber membranes, starting from the end face, so that each hollow fiber membrane is surrounded by the potting mass at its respective end. The curable potting mass is a mixture of prepolymers that is self-curing, which reacts within a period of time, the so-called potting time, to form a cured polymer. The potting time of the curable potting mass is adjusted so that the curable potting mass is able to flow and can be processed in the potting of the hollow fiber membranes in the liquid state. During potting, the ends of the hollow fiber membranes are embedded in the potting mass in such a way that they are fixed to the end sections of the filter housing. The potting mass seals the end region of the filter housing.The packing mass is substantially plate-shaped and is arranged in the end region of the filter housing perpendicular to the longitudinal axis of the cylindrical housing.

[025] In contrast to the process described in the prior art, the potting mass is not supplied through lateral openings in the end region of the filter housing into the interior of the filter housing and between the fibers of the hollow fiber membrane bundle. Preferably, the potting mass is directed exclusively from the end face of the hollow fiber membrane bundle between the ends of the hollow fiber membranes to achieve uniform mass distribution. Petition 870250089363, dated 10 / 01 / 2025, page 19 / 48 10 / 26 potting between the hollow fiber membranes with only a small meniscus shaping of the potting mass.

[026] In another embodiment of the first aspect, the projection of the filling cap is a partially circumferential projection that extends partially circumferentially over the exterior of the filter housing end region. The projection of the filling mass ensures that the curable filling mass can be fully introduced into the filling zone in the filter housing end region. Through the projection, it is no longer necessary to introduce the curable filling mass into the filling zone by means of a liquid connection. Since the projection on the filling cap is partially circumferential, no special alignment of the filter housing is required. The filling caps can therefore be placed in the filter housing end region in an automated process.

[027] In another embodiment of the first aspect, the sealing cap is positively seated in the end region of the filter housing and the curable filling mass is drained to the end face of the hollow fiber membrane bundle ends via through openings between the filling cap and the outside of the filter housing end region. The filling cap can thus be positively seated in the end section of the filter housing, but at the same time a continuous influx of filling mass to the end face of the hollow fiber membrane bundle is enabled, so that the curable filling mass penetrates from the end face between the hollow fiber membranes against the direction of centrifugal forces. In order to provide the through openings when the cap is in the assembled state, groove-shaped recesses are arranged on the inside of the cap.

[028] In a further embodiment of the first aspect, the filling cap comprises a second receiving portion, the Petition 870250089363, dated 10 / 01 / 2025, page 20 / 48 11 / 26 second receiving portion receiving the end face of a second bundle of hollow fiber membranes inserted into a second filter housing and the end region of the second filter housing, wherein a transfer channel is arranged between the first and second receiving portions of the potting cap through which the curable potting mass flows from the first receiving portion to the second receiving portion and to the end face of the second bundle of hollow fiber membranes, and the ends of the hollow fiber membranes of the second bundle of hollow fiber membranes are potted into the second filter housing.

[029] According to this embodiment of the process, it is possible to fuse two bundles of hollow fiber membranes into two filter housings simultaneously. Furthermore, however, a filling cap can be configured to have first, second and third or first, second, third and fourth receiving regions for the end regions of the filter housing so that three bundles of hollow fiber membranes or four bundles of hollow fiber membranes can be filled simultaneously with a curable filling mass into the respective filter housings according to the method of the invention. Therefore, several filter housings can be fused simultaneously in one apparatus, which reduces the design effort of the apparatus for filling the bundles of hollow fiber membranes into the filter housings.

[030] According to a further embodiment of the first aspect, the filling mass is injected simultaneously into the protrusions of two filling caps, each of which is arranged in two filter housings, which are arranged one above the other, preferably in a cross position. Filling caps having one, two, three, four or more receiving portions may be used, with transfer channels being arranged between the respective receiving portions so that Petition 870250089363, dated 10 / 01 / 2025, p. 21 / 48 12 / 26 The curable filling mass is transferred from the first receiving area to the second, third, and fourth or additional receiving areas. For example, two filter housings can be arranged in pairs, each with a filling lid with two receiving portions crossed one above the other. Similarly, three or four filter housings connected to filling lids with three or four receiving portions can also be arranged crosswise with another three or four filter housings connected to filling lids with three or four receiving areas one above the other. Each of these arrangements serves to minimize the design effort of the filling apparatus.

[031] In another embodiment according to the first aspect, the curable filling mass is supplied in a filling chamber and the filling chamber is rotated synchronously with the rotation of one or more filter housings. The curable filling mass is supplied through filling channels, in each case in a radial direction to the axis of rotation of the filter housings, in the direction of the projection of the filling cap. In this case, the filling chamber is centrally located between two filling caps, each of which is mounted on opposite end regions of one or more filter housings. According to this embodiment, the curable filling mass is discharged through the filling channels by the centrifugal forces generated during rotation. The filling channels are arranged in such a way that the filling mass is directed to the filling caps in a radial direction to the axis of rotation.The discharge of the curable filling mass from the filling chamber can thus be caused solely by centrifugal forces. The rotation of the filter housings and the filling chamber can be synchronized electronically or mechanically.

[032] In another modality according to the first aspect, the Petition 870250089363, dated 10 / 01 / 2025, p. 22 / 48 13 / 26 The curable filling mass bypasses an air gap during injection into the filling gap projection due to centrifugal forces and is captured by the filling mass protrusion. In particular, in a further embodiment, the filling mass is discharged from the filling chamber by centrifugal forces and flows through the filling channels in a radial direction to the axis of rotation and is injected through an opening at the end of the filling channels. Therefore, the filling chamber and the filling lid do not have to be connected by specially supplied fluid connection channels.

[033] In another embodiment according to the first aspect, the filter housing and the filling chamber are arranged on a mounting table and the mounting table is rotated around the axis of rotation (R). According to this embodiment, the filter housing can be fixed to the mounting table by a retaining device and the filling chamber is also installed on the mounting table by means of a fixing device. In this case, the rotations of the filling chamber and the filter housing are mechanically coupled. Therefore, it is no longer necessary to synchronize the rotation of the filling chamber and that of the filter housing. In an alternative embodiment, the filling chamber and the mounting table can be mounted separately, and the rotations of the filling chamber and the filter housing can be electronically synchronized. This may be the case in particular if several, for example, 2, 4, 6, 8, 10 filter housings are arranged on an assembly table.

[034] A further embodiment of the first aspect is characterized in that on the assembly table at least one additional filter housing (200), for example, a second (200), third (300) and a fourth (400) filter housing, each having arranged in the same bundle of hollow fiber membranes, is arranged on the assembly table. The arrangement of several filter housings on an assembly table enables economical production, especially when Petition 870250089363, dated 10 / 01 / 2025, page 23 / 48 14 / 26 various filter housings are connected to each other by potting caps with multiple receiving areas.

[035] According to this embodiment, it is advantageous that the respective end faces of the first and at least one additional hollow fiber membrane bundle, for example, the end faces of the second, third and fourth hollow fiber membrane bundles and the respective end regions of the first and at least one additional filter housing, for example, the respective end regions of the second, third and fourth filter housings, are respectively received in the first and second receiving portions of a potting cap, and the ends of the first and at least one additional, for example, second, third and fourth hollow fiber membrane bundles in the respective first and at least one additional, for example, second, third and fourth filter housings, are potted simultaneously.

[036] In a second aspect, the invention relates to an apparatus for packaging a bundle of hollow fiber membranes into a filter housing to perform a method according to an embodiment of the first aspect of the invention, the apparatus comprising an assembly having a mounting table with at least one retaining device for at least one filter housing with a bundle of hollow fiber membranes arranged therein and having an elongated extension, in particular a tubular elongated extension, along a longitudinal extension axis, and packaging caps fitted into respective end regions of the filter housing, and comprising a packaging chamber, in which the mounting table is rotatably mounted around a rotation axis that is perpendicular to the longitudinal extension axis of the filter housing.

[037] In particular, in one embodiment, the apparatus is characterized in that the filling chamber is fixedly installed on the assembly table and thus performs the same rotation as the table. Petition 870250089363, dated 10 / 01 / 2025, p. 24 / 48 15 / 26 assembly and of the filter housings installed in the retention device. According to this embodiment, the curable filling mass can be discharged towards the filling cap via filling channels in a radial direction to the axis of rotation (R) and injected into the projection of the filling cap via terminal openings in the filling channels through an air gap. The filling chamber and filter housing are advantageously arranged on the assembly table in such a way that the rotation of the assembly table around the axis of rotation passes through the centers of gravity of the filling chamber and one or more filter housings.

[038] In an alternative embodiment according to the second aspect, the assembly table of the filling apparatus comprises retaining devices for an even number of filter housings, in particular 2, 4, 6, 8 filter housings. It is particularly advantageous that the assembly table has retaining devices for filter housings that are connected in pairs, optionally in an arrangement of three or four, to the respective filling lids with two receiving areas, optionally with three or four receiving areas.

[039] In a third aspect, the invention relates to a filling cap for filling at least two bundles of hollow fiber membranes with a curable filling mass, each of which is arranged in a first and a second filter housing, wherein the filling cap comprises a first receiving region for receiving an end region of the first filter housing and of the first bundle of hollow fiber membranes arranged therein and at least a second receiving portion for receiving an end region of the second filter housing and of the second bundle of hollow fiber membranes arranged therein, wherein the first receiving portion and the second receiving portion are connected to a transfer passage through which the curable filling mass can flow from the first portion Petition 870250089363, dated 10 / 01 / 2025, page 25 / 48 16 / 26 receiving portion for the second receiving portion, and wherein the filling cap has at least one partially circumferential projection with which a curable filling mass injected through an air gap can be captured and drained to the first receiving portion.

[040] By means of this filling cap, two filter housings can be filled simultaneously according to the method of the invention. In an alternative embodiment, such a filling cap may also include third and fourth receiving portions and include a transfer channel between the second receiving portions and the third receiving portions and between the third and fourth receiving portions. The filling cap is designed such that it can be positively fitted into the end regions of a first filter housing and a second filter housing at the same time. The filling mass flows to the end faces of the hollow fiber membrane bundles via through openings arranged in the positive seat between the filling cap and the end section of a filter housing in the closing cap.

[041] In a fourth aspect, the invention relates to a method of manufacturing a hollow fiber membrane filter comprising the method steps according to an embodiment of the first aspect of the invention, and further comprising the steps of exposing the lumen of the hollow fiber membranes by removing a layer of the potting mass on the face of the potted ends of the hollow fiber membranes, sealing filter caps to the respective end regions of the filter housing in order to form two flow spaces, the first flow space comprising the internal volume of the hollow fiber membranes and the second flow space comprising the volume between the hollow fiber membranes and the filter housing.

[042] According to the method, hollow fiber membrane filters can be produced with a low potting height, a Petition 870250089363, dated 10 / 01 / 2025, page 26 / 48 17 / 26 since only a less pronounced meniscus depth is formed when hollow fiber membranes are potted into the filter housing according to the first aspect method.

[043] In a fifth aspect, the invention relates to a hollow fiber membrane filter comprising a filter housing, the filter housing comprising two end regions, each having two termination edges, a bundle of hollow fiber membranes disposed in the filter housing, the bundle of hollow fiber membranes being embedded in a potting mass at the ends of the hollow fiber membranes with the filter housing in the end region of the filter housing, filter caps being securely fastened to the end regions of the filter housing, respectively, the hollow fiber membrane filter having two flow spaces, the first flow space comprising the internal volume of the hollow fiber membranes and the second flow space comprising the volume between the hollow fiber membranes and the filter housing, characterized in that the potting height of the potting mass is from 3 to 7 mm, in particular from 4 to 6 mm,or 4.5 to 5.5 mm. The potting height at the center of the hollow fiber membrane bundle is less than at the edge of the hollow fiber membrane bundle adjacent to the filter housing. The potting height is the smallest thickness of the potting mass in the potting zone.

[044] In a further embodiment of the fifth aspect, the meniscus depth of the cured potting cap is preferably less than 3 mm, 2 mm or 1 mm. Meniscus depth in this context means the difference in the thickness of the potting mass in the potting zone between the point of least thickness and the thickness of the potting mass at the edge of the hollow fiber bundle.

[045] In one embodiment, the inner diameter of the filter housing of a hollow fiber membrane filter according to the invention is 25 to 45 mm, preferably 30 to 40 mm. In particular, Petition 870250089363, dated 10 / 01 / 2025, p. 27 / 48 18 / 26 From 6,000 to 15,000, preferably 9,000 to 15,000 hollow fiber membranes can be arranged in the filter housing of the hollow fiber membrane filter, so that the hollow fiber membrane filter can have a membrane surface area of ​​1.2 to 2.5 m². The filter housing of the hollow fiber membrane filter is preferably tubular, in particular cylindrical. The “membrane surface area” is calculated as the product of the internal surface area of ​​the hollow fiber membranes and the number of hollow fiber membranes arranged in the cylindrical housing of the hollow fiber membrane filter. The internal surface area of ​​the hollow fiber membranes is calculated as the product of the internal diameter of a hollow fiber membrane, the circle constant π, and the effective length.

[046] In alternative embodiments, the membrane surface area of ​​the hollow fiber membrane filter of the invention is 1.3 to 1.9 m2, or 1.3 to 1.8 m2, or 1.4 to 1.7 m2.

[047] In certain embodiments, the hollow fiber membrane filters of the present invention have an aspect ratio of 8.0 to 10.0 with a membrane surface area of ​​1.6 to 2.0 m2. In alternative embodiments, the hollow fiber membrane filters have an aspect ratio of 8.5 to 9.5 with a membrane surface area of ​​1.3 to 1.6 m2. In the context of the present application, “aspect ratio” is understood as the quotient of the effective length of the hollow fiber membranes and the internal diameter of the cylindrical housing of the hollow fiber membrane filter.

[048] In the context of the present application, the “effective length” of the hollow fiber membrane filter is understood to be the distance between the packing masses at the point of least packing thickness at which mass transfer can effectively occur through the hollow fiber membranes. In certain embodiments, the hollow fiber membrane filter according to the present invention has an aspect ratio of 8 to 12, 8.5 to 11, 8.5 to 10, or 9 to 10. Petition 870250089363, dated 10 / 01 / 2025, page 28 / 48 19 / 26

[049] The effective length of the hollow fiber membranes in these embodiments is correspondingly 270 to 320 mm. In an advantageous embodiment of the invention, the hollow fiber membrane filter is characterized in that the effective length of the hollow fiber membranes is 280 to 320 mm, in particular 285 to 310 mm or 290 to 310 mm. In particular, the selection of the aspect ratio, membrane surface area and effective length in the ranges described above allows for effective removal of medium molecules in extracorporeal blood purification therapies such as hemodialysis or hemofiltration. In this context, blood serum proteins with a molecular weight of 10,000 daltons to 50,000 daltons are referred to as medium molecules. At the same time, however, it also prevents excessive pressure drop along the length of the hollow fiber membrane lumens on the lumen side, resulting in the problem of excessive hemolysis or membrane obstruction.

[050] The effective length of the hollow fiber membrane is increased by the low potting height of the cured potting mass. Therefore, with the same filter housing length, higher performance parameters of the hollow fiber membrane filter can be achieved with the reduced potting height according to the fourth or fifth aspect of the invention.

[051] The inner diameter of the cylindrical housing can be reduced to 25 to 35 mm, or 25 to 33 mm, or 28 to 33 mm, within the aspect ratio defined according to the invention, so that an improved incident flow of the hollow fiber membranes in the second flow chamber can occur.

[052] Preferably, hollow fiber membranes made of polysulfone and polyvinylpyrrolidone are used for the production of a hollow fiber membrane filter according to the invention.

[053] The potting mass in which the hollow fiber diaphragms are embedded and sealed in the respective end regions of the cylindrical housing is preferably polyurethane. Petition 870250089363, dated 10 / 01 / 2025, page 29 / 48 20 / 26

[054] The filter housing and filter covers are preferably made of a polypropylene material. A polypropylene housing is advantageously suitable for accommodating long fiber bundles in a safe mode of production.

[055] In an advantageous embodiment of the invention, the hollow fiber membrane filter is characterized in that the density of the hollow fiber membranes is greater than 50%, preferably greater than 57%, preferably greater than 60%, most preferably greater than 62%. In certain embodiments, the density of the hollow fiber membranes is not greater than 70%. In the context of the present application, “density of the hollow fiber membranes” is understood to be the proportion within the cylindrical housing that is occupied by the hollow fiber membranes. The density of the hollow fiber membranes is calculated as the percentage ratio of the sum of the cross-sectional areas of the hollow fiber membranes, measured at the outer fiber diameter, to the cross-sectional area of ​​the cylindrical housing of the hollow fiber membrane filter, wherein the cross-sectional area of ​​the cylindrical housing is understood to be only the cross-sectional area given by the inner diameter, measured at the narrowest point of the housing.Packaging during the manufacture of hollow fiber membrane filters is particularly difficult if the density of packaging is particularly high. In contrast, the separation properties, measured as clearance for low molecular weight substances, are particularly high when the density of packaging is high and, if necessary, the aspect ratio is also high. It has been shown that for such hollow fiber membrane filters, the teaching of the present invention is particularly advantageous. The manufacturing process is simplified, costs are reduced, and material consumption, in particular packaging material consumption, is decreased. Description of the Invention with Reference to the Figures

[056] The invention is further explained below with reference to the figures, in which: Petition 870250089363, dated 10 / 01 / 2025, page 30 / 48 21 / 26 Figure 1 is a schematic representation of a filter housing with a seated packing cap and the flow path schematically represented for a curable packing mass; Figure 2 is a schematic representation of a potting cap with two receiving portions and two filter housings arranged therein, and the flow path schematically represented of a curable potting mass; Figure 3 is a schematic representation of a cylindrical filter housing in which a packing mass is located in the respective end regions; Figure 4 is a schematic representation of a part of a filter housing in which the packing mass is located in an end region; Figure 5 is a drawing of an assembly table for an apparatus according to the invention, with four filter housings retained therein.

[057] Figure 1 shows an internal view of a portion of a cylindrical filter housing 100 with an end region 105 and a termination edge 107 surrounding an open end 103 of the filter housing 100. Additionally shown in Figure 1 is a potting cap 109 in cross-sectional view, which is positively seated on the end region 105, covering an end face 108 of a hollow fiber membrane bundle, the hollow fiber membrane bundle not being shown in Figure 1. The receiving portion 110 of the potting cap exposes the end face 108 of the hollow fiber membrane bundle and a portion of the end region 105 of the filter housing. The potting cap 109 includes a projection 111 that is suspended over the end region 105 and a portion of the filter housing 100.Furthermore, the path 112 of an influx of a curable potting mass is shown schematically by the arrows. In Figure 1, a filter housing 100 is shown having side openings 101. These openings are provided. Petition 870250089363, dated 10 / 01 / 2025, page 31 / 48 22 / 26 to allow an inflow or outflow of fluid to the second flow chamber of the hollow fiber membrane filter in its functional use. Advantageously, these openings 101 are located on the side of the filter housing 100, which is directed towards the observer in the representation shown. The openings are not relevant in the context of the method according to the first aspect of the invention. Furthermore, Figure 1 shows a filling channel 511 through which a curable filling mass can be discharged via opening 512. Between the opening 512 and the projection 111, there is an air gap that is bypassed by the curable filling mass during the filling process. The discharged curable filling mass is captured by the protrusion 111 of the filling cap 109.As shown in Figure 1, the curable packing mass thus flows between an outer region of the end region 105 of the filter housing 100 and the wall of the packing cap, overflowing through the termination edge 107 and causing the packing mass to flow to the end face 108. As shown in Figure 1, the packing mass flows from the face to the end of the hollow fiber membrane bundle and is distributed between the hollow fiber membranes, not shown in Figure 1. The discharge of the curable packing mass through the packing channel 511 and through the opening 512, as well as the flow of the curable packing mass along the packing cap, thus is caused by rotation that is performed around the axis of rotation R.

[058] Figure 2 shows a schematic cross-sectional drawing of an additional embodiment for packaging hollow fiber membrane bundles in a filter housing. The packaging cap 209 shown in Figure 2 has two receiving portions 210a and 210b and is positively fitted into the end regions 105, 205 of two filter housings 100 and 200. In a symmetrical arrangement, the packaging cap 209 has two projections 211a and 211b. According to the arrows shown in Figure Petition 870250089363, dated 10 / 01 / 2025, pp. 32 / 48 23 / 26 2. The flow path of the curable potting mass is shown; however, only projection 211a is used in the embodiment shown to introduce the curable potting mass into the potting cap. The potting cap 209 is positively seated on the end regions 105 and 205 of the filter housings 100 and 200 and covers the respective end faces of the hollow fiber membrane bundles shown in Figure 2, whose bundles are not shown or are not visible in the cross-sectional drawing. With references 214a and 214b shown in Figure 2, one of several through openings through which the curable potting mass can flow between the potting cap and the outside of the filter housing end region to the end face of the hollow fiber membranes is shown.According to the arrows shown, the discharged curable potting mass is captured by projection 211a and flows between the wall of the potting cap and the outer section of the end region 105 of the filter housing 100 over the end edge 107 to the face of the hollow fiber membrane bundle of the first filter housing 100, where it is distributed among the hollow fiber membranes. In the process, the curable potting mass passes through openings 214a to the face of the hollow fiber membrane bundle. In this case, the potting mass flows through the first receiving portion 210a and flows through the transfer channel 213 to the second receiving portion 210b through openings 214b to the face of the hollow fiber membrane bundle of the second filter housing 200.According to the embodiment shown in Figure 2, two bundles of hollow fiber membranes can be simultaneously potted into a first and a second filter housing, respectively. Similar to the embodiment according to Figure 1, the discharge of the curable potting mass through the potting channel and through the opening, as well as the flow of curable potting mass along the potting cap, is caused by the rotational movement that is performed around the axis of rotation. Petition 870250089363, dated 10 / 01 / 2025, pp. 33 / 48 24 / 26 R.

[059] Figure 3 shows an embodiment of a filter housing 100 in a side view, as it is used in the process according to the invention and is rotated about the axis of rotation R. The filter housing has a cylindrical shape along a longitudinal extension axis L. In the embodiment shown, the filter housing 100 includes openings 101a and 101b in the respective end regions 105 and 106. The openings are used in the hollow fiber membrane filter developed to drain liquid, for example, dialysate, if the hollow fiber membrane filter is a dialyzer for extracorporeal blood treatment, to the second flow space of the hollow fiber membrane filter, which comprises the space between the hollow fiber membranes within the filter housing.Furthermore, Figure 3 shows, at the respective ends 103 and 104 of the filter housing, a packing mass 113a and 113b inside the end regions 105 and 106 in schematic representation. The packing mass is plate-shaped and embeds the hollow fiber membrane bundle (not shown in Figure 3), fitting in a sealed manner into the respective end regions 105 and 106 of the filter housing 100. The surface of the packing mass is concavely curved in the direction of the rotation axis R and forms the typical meniscus. Figure 3 also shows the termination edges 107a and 107b of the filter housing at the respective end regions 105 and 106.As described above, in the method according to the invention, the termination edges on the outside of the end regions are overflowed in such a way that the potting mass flows to the end faces 108a and 108b shown in Figure 3 and flows further between the hollow fiber membranes inside the end sections 105 and 106. According to the process of the invention, care is taken to ensure that the openings 101a and 101b are not covered by the curable potting mass. Based on the method according to the invention, the potting height and a. Petition 870250089363, dated 10 / 01 / 2025, pages 34 / 48 25 / 26 The depth of the potting mass meniscus in the end regions 105 and 106 can be kept low enough so that the openings 101a and 101b shown are not covered.

[060] The filling height and meniscus depth produced by the method according to the invention are further exemplified in Figure 4. Figure 4 shows an enlarged view of the top of the filter housing 100 of Figure 3. According to Figure 4, it is shown that the filling height of the filling mass 113a adjacent laterally to the end region 105 of the filter housing 100 is 6.0 mm. In the middle of the filling mass the filling height is 5.0 mm. The meniscus depth is thus 1 mm. The meniscus depth is calculated as the value of the highest filling height minus the value of the lowest filling height.

[061] Figure 5 shows an embodiment of a mounting table 501 of an apparatus according to the invention for receiving the four filter housings 100, 200, 300, 400 for packaging bundles of hollow fiber membranes into the respective filter housings. In the embodiment shown, filter housings are fixed in pairs at the end regions of the filter housings by means of the closing caps 209, each having two receiving portions. The closing caps are designed in detail as shown in Figure 2. Of the four caps shown in Figure 5, two of the four caps shown are referenced. The pairs of filter housings are fixed transversely to the mounting table by the retaining devices 502A, 502B, 502C, 502D. The assembly table is rotatably mounted in such a way that the assembly table can rotate around the axis of rotation R. The bearing for the rotational movement is not shown in Figure 5.The axis of rotation R shown in Figure 5 is perpendicular to the longitudinal axis L of the filter housings, shown in Figure 5 only for filter housing 200. In the arrangement shown in Figure 5, the axis of rotation is also positioned perpendicular. Petition 870250089363, dated 10 / 01 / 2025, pages 35 / 48 26 / 26 to the longitudinal extension axis of each of the other filter housings 100, 300, 400, whose axes, however, are not shown in Figure 5. The mounting table 501 and the arrangement of the filter housings are arranged in such a way that rotation occurs around the center of gravity of each filter housing. Reference 510 in Figure 5 is assigned to the filling chamber. During filling, the filling chamber contains the curable filling mass for filling the hollow fiber membrane bundles into the filter housings. The hollow fiber membrane bundles are not shown in Figure 5. The filling channels 511A, 511B, 511C, 511D extend from the filling chamber 501, the orientation of the filling channels being such that the filling material is discharged by the rotation of the filling chamber around the axis of rotation R in a radial direction relative to the axis of rotation.At the ends of the filling channels 511A, 511B, 511C, 511D are the openings 512A, 512B, 512C, 512D. The filling mass can exit through the openings during rotation and be injected into the projection 211a of the filling cap 209. According to Figure 5, the filling mass thus bypasses an air gap during rotation of the mounting table 501, and the filling mass is captured by a respective projection of the filling caps 209. The filling chamber 510 is connected to the mounting table by one or more fasteners 513. The position of the filling chamber on the mounting table is selected such that the axis of rotation passes through the center of gravity of the filling chamber. As shown, the filling chamber is arranged above the pairs of filter housings arranged transversely. The mounting table, filter housing, and filling chamber consequently perform an identical rotational movement during rotation. Petition 870250089363, dated 10 / 01 / 2025, pp. 36 / 48

Claims

1 / 6 CLAIMS 1. Method of potting the ends of a bundle of hollow fiber membranes into a filter housing (100) with a potting mass characterized by comprising the steps of inserting a bundle of hollow fiber membranes into a filter housing (100) that is open at two ends (103, 104) and has a longitudinal extension axis (L), which in particular is a tubular or cylindrical filter housing having a longitudinal extension axis (L), the filter housing having an inner side and an outer side, the filter housing having respectively at the two open ends (103, 104) an end region (105, 106), each having a termination edge (107, 107a, 107b) for the open end (103, 104) of the filter housing,wherein hollow fiber membranes are inserted into the filter housing such that the hollow fiber membrane bundle (101) forms an end face (108) at the termination edge (101) of the filter housing (100), placing a potting cap (109, 209) on at least one end region (105) of the filter housing (100), the potting cap (109, 209) comprising at least a first receiving portion (110, 210a) for receiving the end face (108) of the hollow fiber membrane bundle and at least one end region (105) of the filter housing (100), and comprising a projection (111, 211a) being suspended over at least one end region (105) on the outside of the filter housing (100), injecting a curable potting mass into the projection (111, 211) of the bottling cap (109,209) such that the curable potting mass flows between the outside of at least one end region (105) of the filter housing (100) and the potting cap (109, 209), the curable potting mass flows over the termination edge (107, 107a, 107b) of the first filter housing (100) of such Petition 870250089363, dated 10 / 01 / 2025, p. 37 / 48 2 / 6 such that the curable potting mass flows to the end face (108) of the hollow fiber membrane bundle formed by the hollow fiber bundle (101), potting the ends of the hollow fiber membrane bundle into the filter housing (100) and allowing the potting mass to cure whereby the filter housing (100) with the hollow fiber membrane bundle is rotated around an axis of rotation (R) that is perpendicular to the longitudinal extension axis (L) of the filter housing, such that the overflow through the termination edge (107,107a) of the filter housing (100) of the packing mass and the influx of the packing mass to the end face (108) of the hollow fiber membrane bundle are effected by the centrifugal forces resulting from the rotation of the filter housing (100)., 2. Method according to claim 1, characterized in that the projection (111, 211a) of the filling cap (109, 209) is a partially circumferential projection that is suspended partially circumferentially over the exterior of at least one end region (105) of the filter housing (100).

3. Method, according to one of the preceding claims, characterized in that the potting cap (109, 209) is positively seated in the end region (105) of the filter housing (100) and the curable potting mass flows to the end face (108) of the hollow fiber membrane bundle through through openings between the potting cap and the outside of the end region (105) of the filter housing.

4. Method, according to any of the preceding claims, characterized in that the potting cap (209) comprises a second receiving portion (210b), the second receiving portion (210b) receiving the end face of a second bundle of hollow fiber membranes inserted into a second filter housing (200) and the end region (205) of the second Petition 870250089363, dated 10 / 01 / 2025, page. 38 / 48 3 / 6 filter housing, wherein a transfer channel (213) is arranged between the first and second receiving portions (210b) of the potting cover (209) through which the curable potting compound flows from the first receiving portion (210a) to the second receiving portion (210b) and to the end face of the second hollow fiber membrane bundle, and the ends of the hollow fiber membranes of the second hollow fiber membrane bundle are potted in the second filter housing.

5. Method, according to any of the preceding claims, characterized in that the curable potting mass is provided in a potting chamber (510) and the potting chamber is rotated synchronously with the rotation of the filter housing (100) and is directed by means of at least one potting channel (511A, 511B, 511C, 511D) radially to the axis of rotation (R) of the filter housing in the direction of the projection (111) of the potting lid (109).

6. Method according to claim 5, characterized in that the curable filling mass, starting from an opening of at least one filling channel (512A, 512B, 512C, 512D), bypasses an air gap during injection into the projection (111) of the filling cap (109) and is captured by the projection (111) of the filling compound.

7. Method according to claim 5 or 6, characterized in that at least one filter housing (100) and the filling chamber (510) are arranged on a mounting table (501) and the mounting table (501) is rotated around an axis of rotation (R).

8. Method according to claim 7, characterized in that at least one additional filter housing (200), for example, a second (200), third (300) and a fourth (400) filter housing, each with a bundle of hollow fiber membranes placed therein, is arranged on the mounting table. Petition 870250089363, dated 10 / 01 / 2025, p. 39 / 48 4 / 6 9. Method according to claim 8, characterized in that the respective end faces of the ends of the first and at least one additional hollow fiber membrane bundle, for example, the end faces of the ends of the second, third and fourth hollow fiber membrane bundles, and the respective end regions (105, 204) of the first and at least one additional filter housing (100, 200), for example, the respective end regions of the second (200), third (300) and fourth filter housings (400), are respectively received in the first (110) and second (210) receiving portions of a potting cap as defined in claim 4, and the ends of the first and at least one additional, for example, second, third and fourth hollow fiber membrane bundles in the respective first (100) and at least one additional, for example, second (200),The third (300) and fourth (400) filter housings are packaged simultaneously.

10. Apparatus for filling a bundle of hollow fiber membranes into a filter housing (100), characterized in that it is for performing a method as defined in any one of claims 1 to 9, comprising an assembly with a mounting table (501) with a retaining device (502) for at least one filter housing (100) with a bundle of hollow fiber membranes arranged therein and an elongated extension, in particular a tubular elongated extension, along a longitudinal extension axis (L), and filling caps (109) placed in the respective end regions (105) of the filter housing (100), and comprising a filling chamber (510), in which the mounting table (501) is rotatably mounted around a rotation axis (R) that is perpendicular to the longitudinal extension axis (L) of the filter housing.

11. Apparatus, according to claim 10, characterized in that the mounting table (501) comprises retention devices (502) for an even number of filter housings, in particular 2, 4, 6, 8, 10 filter housings.

12. Packaging cap (213) for packaging at least two bundles of hollow fiber membranes with a curable packaging compound (112) arranged in a first (100) and a second (200) filter housing, respectively, characterized in that the packaging cap (209) has a first receiving portion (210a) for receiving an end region (105) of the first filter housing (100) and the first bundle of hollow fiber membranes arranged therein and at least a second receiving portion (210b) for receiving an end region (205) of the second filter housing (200) and the second bundle of hollow fiber membranes arranged therein, wherein the first receiving portion (210a) and the second receiving portion (201b) are connected to a transfer passage (213) through which the curable packaging material can flow from the first receiving portion. (210a) for the second portion of receipt (210b),and wherein the filling cap (209) has at least partially circumferentially a projection (211) by means of which a curable filling mass injected by means of an air gap can be captured and drained to the first receiving portion (210a).

13. Method of manufacturing a hollow fiber membrane filter, characterized in that it comprises the method steps as defined in claims 1 to 9, and further comprising the steps of exposing the lumen of the hollow fiber membranes by removing a layer of the potting compound from the face of the potted ends of the hollow fiber membranes, sealing filter caps to the respective end regions of the filter housing in order to form two flow spaces, the first flow space comprising the internal volume of the hollow fiber membranes and the second flow space comprising the volume between the hollow fiber membranes and the filter housing.

14. Hollow fiber membrane filter characterized by comprising a filter housing, the filter housing comprising: two end regions (105, 106), each with two termination edges (107a, 107b), a bundle of hollow fiber membranes disposed in the filter housing, the bundle of hollow fiber membranes being embedded in a potting compound at the ends of the hollow fiber membranes with the filter housing in the end region of the filter housing, filter caps sealed to the end regions of the filter housing, respectively, wherein the hollow fiber membrane filter has two flow spaces, the first flow space comprising the internal volume of the hollow fiber membranes and the second flow space comprising the volume between the hollow fiber membranes and the filter housing, wherein the potting height of the potting compound is 3 to 7 mm, in particular 4 to 6 mm, or 4.5 to 5.5 mm. mm.

15. Hollow fiber membrane filter, according to claim 14, characterized in that the meniscus depth is less than or equal to 3 mm, preferably less than or equal to 2 mm, more preferably less than or equal to 1 mm.

16. Hollow fiber membrane filter, according to claim 14 or 15, characterized in that the aspect ratio of the effective length of the hollow fiber membranes and the inner diameter of the cylindrical housing is 8 to 12.

17. Hollow fiber membrane filter, according to claims 14 to 16, characterized in that the density of the hollow fibers in the filter housing is greater than 57%, in particular greater than 60%, and more particularly greater than 62%. Petition 870250089363, dated 10 / 01 / 2025, pp. 42 / 48

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