Hollow Fiber Membrane Filter

Abstract

The present invention relates to a hollow fiber membrane filter including a plurality of hollow fiber membranes and at least two support rings, each of the hollow fiber membranes being surrounded by a support ring in an end region of the hollow fiber membrane filter and molded in a molding compound, each of the support rings having a peripheral protrusion located at an upper edge and protruding beyond an outer side of a peripheral side wall of the support ring, the peripheral protrusion resting on a closing edge of a first and second end region of a cylindrical housing of the hollow fiber membrane filter.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This application relates to hollow fiber membrane filters, and in particular to hollow fiber membrane filters for extracorporeal blood processing. [Background technology]

[0002] In the production of hollow fiber membrane filters, a bundle of hollow fiber membranes previously produced in a spinning and bundling process is inserted into the housing of the hollow fiber membrane filter. As a type of housing, a cylindrical housing is used almost exclusively. The ends of the hollow fiber membranes are potted in the end parts of the hollow fiber membrane filter with a potting mass, usually polyurethane, and are thereby fixed to the housing. The end regions of these potting masses are milled or cut off to expose the open ends of the hollow fiber membranes. Then, end caps are placed on the end areas of the cylindrical housing. That is, two flow spaces are formed in the hollow fiber membrane filter. With one liquid port on each of the end caps and two liquid ports on the cylindrical housing, respectively, the fiber interior can be perfused with a first liquid, for example the patient's blood, and the internal space surrounding the hollow fiber membranes can be perfused with a second liquid, for example the dialysis solution. In order to use such hollow fiber membrane filters in extracorporeal blood treatment or biopharmaceutical processes, it is necessary to supply such hollow fiber membrane filters in a sterile state.

[0003] A widely used sterilization process is the steam sterilization process. After production, the entire hollow fiber membrane filter is perfused with sterilizing water vapor in multiple stages through the liquid connections. The sterilizing steam is introduced into the hollow fiber membrane filter at temperatures above 100 ° C and atmospheric overpressure. Due to the different materials used in the production of the hollow fiber membrane filter, the individual components of the hollow fiber membrane filter expand at different rates. Plastics consisting of polyethylene, polypropylene, polyesters such as PET or PBT, polymethyl methacrylate, polystyrene or polycarbonate are commonly used for the housing of hollow fiber membrane filters. Polyurethane is usually used as the filling material. Polymers of polysulfone and polyvinylpyrrolidone are mainly used as materials for hollow fiber membranes. As a result, significant material distortions can occur in the hollow fiber membrane filter during the steam sterilization process.

[0004] Therefore, cracks in the embedding mass are frequently observed after steam sterilization of hollow fiber membrane filters. These cracks are due to the different expansion behavior of the housing, the embedding mass, and the hollow fiber membrane. These defective hollow fiber membrane filters are detected and discarded in the quality control procedures of the industrial hollow fiber membrane manufacturing process. Such defective hollow fiber membrane filters are undesirable. On the other hand, such defective production leads to higher production costs. Furthermore, the process flow in the industrial production of hollow fiber membrane filters is also interrupted, which leads to production delays and therefore also higher production costs.

[0005] WO 01 / 60502 A1 describes a hollow fiber membrane filter in which the hollow fiber membranes are essentially embedded in only one support ring. The support ring has several lugs, bars and shoulders at one end. The hollow fiber membrane bundle is simply connected to the support ring through an embedding mass, but not to the housing of the hollow fiber membrane filter. To prevent the support ring from binding to the housing, the embedding mass must be inside the support ring. From the design of the hollow fiber membrane filter shown in WO 01 / 60502 A1, it can be inferred that this last-mentioned requirement is demanding from the point of view of process technology and therefore difficult to implement respectively in the mass production of hollow fiber membrane filters, which means that this process step may be prone to errors. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO 01 / 60502 A1 [Patent Document 2] EP 2 024 067 A1 [Patent Document 3] EP 3 423 173 A1 Summary of the Invention [Problem to be solved by the invention]

[0007] It was therefore an object of the present invention to provide a hollow fiber membrane filter which is resistant to the material expansion and distortion caused by the steam sterilization process compared to prior art membrane filters, but which is also relatively simple to produce. [Means for solving the problem]

[0008] The object of the present invention is solved by a hollow fiber membrane filter having the features of claim 1. Claims 2 to 11 represent preferred embodiments.

[0009] Furthermore, the object of the present invention is solved by a manufacturing process as claimed in claim 12.

[0010] Furthermore, the object of the invention is solved by using a support ring according to claims 13 to 15. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view of a section of an end portion of a hollow fiber membrane filter. [Diagram 2] FIG. 2 is a view of an end portion of a cylindrical housing of a hollow fiber membrane filter with a support ring disposed thereon. [Figure 3a] FIG. [Figure 3b] FIG. 13 is a dimensioned cross-sectional view of a support ring with a conical inner surface of the circumferential side wall. [Figure 3c] FIG. 13 is a dimensioned cross-sectional view of a protrusion of a support ring with a groove. [Figure 4a] FIG. 2 is a dimensioned side view of a support ring with a conical zone I and a cylindrical zone II on the inside of its circumferential side wall. [Figure 4b] FIG. 2 is a cross-sectional view with dimensions of a support ring having a conical zone I and a cylindrical zone II on the inside of the circumferential side wall, the edges of which are rounded on the inside of the circumferential side wall. [Figure 5a] FIG. 2 is a dimensioned cross-sectional view of a support ring with a tapered inner circumferential sidewall and an undercut at the transition from the circumferential sidewall to a protrusion on the outer side of the support ring. [Figure 5b] FIG. 13 is a dimensioned cross-sectional view of a support ring projection with grooves and undercuts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The dimensioning data in Figures 3a to 5b refer to units of millimetres.

[0013] In the following, the invention will be described with reference to Figures 1 to 5b. In a first aspect, the invention comprises a cylindrical housing 101 extending longitudinally along a central axis A having an inside 102, an outside 103, a housing interior 104, a first end portion 105 having a first terminal edge 106, and a second end portion having a second terminal edge, at least a first fluid port 107 disposed in the first end portion of the cylindrical housing, and optionally a second fluid port disposed in the cylindrical housing 101 and connected to the first end portion 105 and the second end portion of the cylindrical housing 101. a plurality of hollow fiber membranes 108 sealably embedded within respective embedment masses 109 of the hollow fiber filter, the ends 110 of the hollow fiber membranes 108 being open such that the lumens of the hollow fiber membranes form a first flow space and the housing interior 104 surrounding the hollow fiber membranes forms a second flow space; and first and second end caps 111 having an interior and an exterior, the first end caps 111 being attached to the first end of the cylindrical housing 101 to form respective inlet and outlet chambers 114 in fluid communication with the first flow space of the hollow fiber membrane filter. Said end caps 111 are laterally connected to the first end portion 105 and the second end portion, respectively, and each of the first and second end caps 111 or cylindrical housings has respective third and fourth fluid access ports 115 for supplying fluid to or draining fluid from the first inlet or outlet chamber 114, each sealably disposed between the respective embedment mass 109 and the inner side 112 of the respective end cap 111, and each of the respective inlet and outlet chambers 114 and 116. 4 laterally, and at least first and second support rings 117 including a circumferential sidewall 118 having an outer side 119 and an inner side 120, an upper edge 121 and a lower edge 122, the support rings being disposed at each of the first and second end portions 105 of the cylindrical housing such that the outer side 119 of each support ring 117 faces the inside of the cylindrical housing 102 at the respective end portion 105, each support ring 117 being disposed at the upper edge 121,The hollow fiber membrane filter has a circumferential projection 123 projecting beyond an outer side 119 of a circumferential side wall 118 of each support ring 117, the circumferential projection 123 bearing against a terminal edge 106 of each of the first and second end portions 105 of the cylindrical housing 101, and each embedment mass 109 being disposed in a liquid-tight manner at least in part at an edge area 124 between the circumferential projection 123 and a sealing ring of each support ring 117.

[0014] The features of this embodiment are illustrated in Figures 1 and 2. In this connection, Figures 1 and 2 show a cross section of only one of the two end parts of the hollow fiber membrane filter, and Figure 2 shows in a schematic diagram only one of the two end parts of the cylindrical housing in which the support ring is located.

[0015] In hollow fiber membrane filters of the above-mentioned type, the expansion of the cylindrical housing during steam sterilization does not directly affect the embedding mass, since the support rings are interposed between the end edge of the cylindrical housing and the embedding mass. This minimizes the transfer of material stresses of the embedding mass due to thermal expansion during steam sterilization. In particular, this is also due to the fact that the embedding mass does not form a part of the cylindrical housing. The ends of the hollow fiber membranes are only embedded in the embedding mass in the respective support ring. The support rings themselves are not firmly installed in the cylindrical housing, but are only pressed onto the end edge of the cylindrical housing through the end caps, the sealing ring and the embedding mass. Furthermore, hollow fiber membrane filters as described above have the advantage that the embedding in the production of hollow fiber membrane filters can be carried out according to conventional and proven methods, for example according to the process as described in EP 2 024 067 A1, and no further embedding process steps need to be developed to embed the hollow fiber membranes in the support rings. This is due to the structural design of the support rings. The projections of the support ring cover the terminal edge of the cylindrical housing to an extent that prevents the embedment from contacting the cylindrical housing through the projections of the support ring.

[0016] In one embodiment, the hollow fiber membrane filter can be configured as a dialysis device. Within the context of this application, the term "dialysis device" is used to describe blood filter devices used for extracorporeal blood treatment. These can be, for example, dialysis filters, hemofilters, or plasma separation filters. In other applications, the hollow fiber membrane filter according to the invention can also be used as a filter for water treatment.

[0017] The term "terminal portions of a cylindrical housing" in the context of this application means portions of a cylindrical housing that extend from the ends of the housing towards the center of the cylindrical housing. The term "terminal portions" indicates portions of a cylindrical housing that take up only a small portion relative to the longitudinal extent of the cylindrical housing. In particular, each of these terminal portions takes up less than one-fifth, one-eighth, one-tenth or one-fifteenth of the total length of the cylindrical housing.

[0018] An embedded zone is present in a portion of the end portion of the cylindrical housing. In the context of this application, the term "embedded zone" refers to a portion of the hollow fiber membrane filter where the hollow fiber membranes are embedded in the embedding mass. The hollow fiber membranes are embedded in the embedding mass in such a way that they are fixed to the support ring. The embedding mass is sealed with the support ring. In particular, the embedded zone is intended to take up less than three-quarters or less than two-thirds or less than half the width of the support ring.

[0019] Adjacent to the recessed zone on the face side, the end cap of the cylindrical housing forms an inflow or outflow chamber. In the context of this application, the term "inflow or outflow chamber" refers to a volumetric area within the hollow fiber membrane filter into which a fluid can enter before entering the first flow space of the hollow fiber membrane filter or after leaving the first flow space of the hollow fiber membrane filter. The first inflow and outflow chambers are sealably connected to the end of the recessed zone and / or the end face of the cylindrical housing through a sealing ring. Each of the first inflow or outflow chambers includes a first fluid port for introducing or discharging a fluid into or from the first inflow or outflow chamber. Thus, the first inlet or outlet chamber is in fluid communication with the first flow space of the hollow fiber membrane filter formed by the lumen of the hollow fiber membrane. In the context of this application, "lumen" or "lumen" is understood to mean the cavity of the hollow fiber membrane.

[0020] The term "sealing ring" is understood to mean a circumferentially or ring-shaped arranged liquid-tight seal. With the hollow fiber membrane filter described above, the sealing ring is arranged between the interior of the end cap and the potting mass. A properly designed sealing ring can be designed as an O-ring and is made of an elastomeric material, for example silicone rubber.

[0021] In the context of the present application, the term "support ring" is understood to mean a sleeve-like component that essentially includes a circumferential side wall. The support ring is suitable for holding the hollow fiber membranes and the embedment mass. The support ring is advantageously made from a plastic material, such as, for example, polyethylene, polypropylene, polyester, polymethylmethacrylate, polystyrene or polycarbonate. Polypropylene is preferred. The support ring has an upper edge and a lower edge. The upper edge is understood to be the closing edge in the direction of the respective end caps. The lower edge is understood to be the closing edge of the support ring towards the middle part of the hollow fiber membrane filter. At the upper edge of the support ring there is a circumferential projection configured to project the circumferential side wall of the support ring outside the support ring. The projection can be flange-like and perpendicular to the central axis of the cylindrical housing. However, it is also preferred that the projection departing therefrom adopts an inclination angle that allows a better centering of the support ring at the end part of the cylindrical housing and also allows the support ring to adopt a low-movement fit at the end part of the cylindrical housing. The flange-like projection may adjoin the circumferential side wall of the support ring at an angle of 90 to 70 degrees relative to the central axis of the cylindrical housing.

[0022] A further embodiment of the first aspect is characterized in that the embedding mass 109 bears at its end region 123 on a projection 123 of the support ring 117 and has the form of a flange 125 arranged between the embedding mass 109 and the sealing ring 116. Individual features of this embodiment are illustrated in FIG. 1. In this embodiment, the entire layer thickness of the embedding mass, in which the ends of the hollow fiber membranes are embedded, is not located between the projection of the support ring and the sealing ring. This embodiment allows to save part of the embedding mass. Moreover, this embodiment allows to make the fit of the embedding mass in the support ring more flexible so that any material strains that occur can be more substantially compensated.

[0023] A further embodiment of the first aspect is characterized in that a respective radially sealing sealing ring is arranged between the outer surface 119 of the respective support ring 117 and the circumferential side wall 118 and the inner surface 102 of the cylindrical housing at the respective end portion 105. In FIG. 2 a circumferential groove 126 is shown, which is intended to receive the radially sealing ring and acts in a sealing manner against the cylindrical housing. In one aspect, the radially sealing sealing ring prevents leakage between the housing interior 104 and the second flow space between the support ring 117 and the inner surface 102 of the cylindrical housing 101 at the end portion 105. Furthermore, the radially sealing sealing ring also allows the support ring to be mounted somewhat flexibly on the end portion of the cylindrical housing, so that further material distortions can be minimized during steam sterilization. The radially sealing sealing ring can be made of an elastomeric resin material, for example silicone rubber.

[0024] Another embodiment of the first aspect is characterized in that the support ring 117 has a circumferential groove 126 in which the sealing ring is at least partially recessed to seal radially on the outside 119 of the circumferential sidewall 118 facing the inside 102 of the cylindrical housing 101 at each end portion 105. This embodiment is partially shown in FIG. 2, which is shown without the sealing ring in the radial direction. By means of this groove, the sealing ring is held in the proper position between the inside 102 of the cylindrical housing 101 and the outside 119 of the circumferential sidewall 118 of the support ring 117.

[0025] Yet another embodiment of the first aspect is characterized in that an axially sealing sealing ring 127 is arranged between the projection 123 of the respective support ring 117 and each of the terminal edges 106 of the respective end portion 105. This embodiment is shown in FIG. 1. The axially sealing sealing ring 127, when in position, provides an improved sealing action between the outer surface 119 of the support ring 117 and the inner surface 102 of the cylindrical housing 101 of the end portion 105. In addition to this, the axially sealing sealing ring 127 also improves the seating of the support ring 117 in the seat of the end portion 105 of the cylindrical housing and allows a low mobility of the support ring 117 in the end portion 105 of the cylindrical housing 101 under conditions of steam sterilization. In one embodiment, the axially sealing sealing ring can be arranged on the support ring 117 in combination with the radially sealing support ring described above.

[0026] In another embodiment of the first aspect, the support ring 117 has a circumferential groove 128 into which the sealing ring 127 is at least partially recessed radially on the side of the projection 123 facing the terminal edge 126 of each end portion 105. The groove 128 is shown in Figures 3b and 3c. This groove holds the radially sealing sealing ring in place and is particularly advantageous when manufacturing hollow fiber membrane filters according to this embodiment.

[0027] A further embodiment of the first aspect is characterized in that the support ring 117 has a circumferential undercut 129 at the transition from its circumferential side wall 118 to the projection 123 on the outer side 119. This embodiment is shown in figures 5a and 5b. The transition from the circumferential side wall 118 of the support ring 117 to the projection 123 on the outer side 119 forms an inner edge. In the context of the present application, the term "undercut" is understood to mean a "relief" at the rotationally symmetric inner edge of the support ring. According to figures 5a and 5b, the wall thickness of the circumferential side wall 118 of the support ring is significantly reduced by the undercut. The projection 123 can therefore be deflected to a small extent relative to the circumferential side wall of the support ring. In such a way, possible material distortions during steam sterilization can be compensated in an improved manner.

[0028] Another embodiment of the first aspect is characterized in that the support ring 117 has a height of 2 to 10%, preferably 2 to 9%, more preferably 3 to 8%, more preferably 4 to 7% of the total length of the hollow fiber membranes 108 in the direction of the longitudinal direction A of the hollow fiber membrane filter. The height of an exemplary embodiment of the support ring 117 is shown in the dimensioned drawing of FIG. 3a. As far as the subject matter of the present invention is concerned, the height of the support ring is understood to be the distance from the upper edge 121 to the lower edge 122 of the support ring. In a commercially available hollow fiber membrane filter used for extracorporeal blood processing, the length of the hollow fiber membranes is about 235 mm. The height of the support ring can be within the ranges mentioned previously and can vary depending on the number of hollow fiber membranes. Depending on the height of the embedding mass, the height of the support ring also provides a lateral support for the hollow fiber membrane bundle in the hollow fiber membrane filter. In particular, it is provided that the height of the embedding mass in the support ring is ¼, preferably ⅓ and less than half the height of the support ring.

[0029] Yet another embodiment of the first aspect is characterized in that the circumferential sidewall 118 of the support ring 117 on each inner side 120 of the support ring is conical in shape at least in sections from the upper edge 121 to the lower edge 122. The conical shape of the inner surface 120 of the support ring 117 is shown in Figures 1, 2, 3a, 3b, 4a, 4b and 5a. This conical shape improves the containment of the hollow fiber membrane bundle and allows embedding of the ends of the hollow fiber membranes in the support ring 117.

[0030] In certain embodiments, the circumferential sidewall 118 of the support ring on the inner side 120 has at least zones I and II, of which zones I and / or II are conical in shape, or at least zone I or II is cylindrical in shape and zone II or I is conical in shape. One embodiment of such a support ring is shown in FIG. 4b. According to FIG. 4b, the support ring 117 has, on the inner side 120 of the circumferential sidewall 118, zone I adjacent to the upper edge 121 of the circumferential sidewall 118 and zone II adjacent to the lower edge 122 of the support ring. In the zone I region, the inner surface 120 of the circumferential sidewall 118 has a conical shape, and in the zone II region, the inner surface 120 of the circumferential sidewall 118 has a cylindrical shape. In a general embodiment, the outer surface 119 of the circumferential sidewall 118 is therefore cylindrical over its entire height up to the projection 123.

[0031] In another elaboration of the above-mentioned embodiment, at least one of the conical zones I or II, or the entire conical shape of the inner surface 119 of the circumferential side wall 118 relative to the direction of the central axis A, has a cone angle of 3 to 15 degrees, preferably 4 to 12 degrees, more preferably 5 to 11 degrees, more preferably 6 to 10 degrees. Such an embodiment is shown in the illustrative figures 3b, 4b and 5a.

[0032] In another detail of the above embodiment, at least the edges 121a, 122a, 130 of the support ring 117 present on the inner side 119 of the circumferential side wall 118 are rounded. A corresponding embodiment is shown in the illustrative Figure 4b. The rounding of the edges prevents damage to the hollow fiber membranes that may come into contact with the inner side 119 of the circumferential side wall 118 of the support ring.

[0033] In a second aspect, the invention relates to the manufacture of a hollow fiber membrane filter according to the features of an embodiment of the first aspect, the manufacture comprising the steps of providing a cylindrical housing 101 extending longitudinally along a central axis A having an inside 102, an outside 103, a housing interior 104, a first end portion 105 having a first terminal edge 106, and a second end portion having a second terminal edge, providing two support rings 117 each having an outside 119 and an inside 120, a circumferential side wall 118 with an upper edge 121 and a lower edge 122, and a protrusion 123 located on the upper edge 121 of each support ring 117 and protruding beyond the outside 119 of the circumferential side wall 118 of each support ring 117, inserting the support rings 117 into each of the end portions 105 of the cylindrical housing 101 such that a support ring 117 is located in each of the first and second end portions 105 of the cylindrical housing, respectively; the steps of: inserting a support ring 117 into each of the end portions 105 of the cylindrical housing 101 such that an outer side 119 of the support ring 117 faces the inner side 102 of the cylindrical housing at the respective end portion 105 and such that each support ring 117 rests on a circumferential projection 123 arranged on an upper edge 121 of the closing edge 106 of each of the first and second end portions 105 of the cylindrical housing 101; inserting a hollow fiber membrane bundle including a plurality of hollow fiber membranes into the cylindrical housing 101 and the respective support rings, embedding ends of the hollow fiber membranes together with the respective support rings 117 in an embedding zone with an embedding mass 109, exposing the ends of the hollow fiber membranes, and attaching end caps 111 to each end portion 105 of the cylindrical housing 101, while inserting a sealing ring 116 between the inner side 112 of the end cap 111 and the end area 124 of the embedding mass 109.

[0034] In this context, "edge region of the embedment mass" is understood to mean the circumferential annular part of the embedment mass which adjoins the support ring but in which no hollow fiber membranes are embedded.

[0035] Exposing the ends of the hollow fiber membranes can be accomplished by known methods, such as, for example, milling or cutting away a portion of the face-side recessed mass.

[0036] According to the method described herein, a hollow fiber membrane filter designed to reduce material stresses in the hollow fiber membrane filter during the process of steam sterilization is manufactured. This process also has the advantage that existing processes for manufacturing hollow fiber membrane filters do not have to be significantly modified. Essentially, in this manufacturing process, during embedding, the embedding mass does not substantially come into contact with the cylindrical housing, so that the hollow fiber membranes in the embedding mass can remain detached from the cylindrical housing. At the embedding stage, for example, the method described in EP 2 024 067 A1 can be used. According to this method, an embedding cap is inserted into the end part of the hollow fiber membrane filter and a liquid embedding mass is introduced into the end part of the hollow fiber membrane filter, so that the hollow fiber membranes are embedded in the embedding zone of the support ring. Since the projections of the support ring support the end edge of the cylindrical housing, the embedding mass is essentially prevented from coming into contact with the cylindrical housing. "Substantially" in this context means that the embedding mass is not able to form a strong bond with the cylindrical housing and the support ring, i.e. the support ring is not bonded at the end part of the cylindrical housing. After the potting mass has hardened, the hollow fiber membranes are secured within the potting mass within the support ring.

[0037] To improve the adhesion between the support ring and the embedded mass, the support ring can be pre-treated. In particular, the surface of the inner surface 120 of the circumferential side wall 118 of the support ring 117 can be modified, for example by plasma or corona treatment, so as to improve the adhesion between the embedded mass and the support ring. In these treatment steps, the surface of the treated support ring is modified to be hydrophilic, which allows for an improved adhesion of the embedded mass. In particular, the above-mentioned surface treatment generates chemically hydrophilic groups, such as hydroxyl or carboxyl groups, which allow a chemical reaction between the embedded mass and the surface.

[0038] The above-mentioned method may comprise further process steps necessary to manufacture a hollow fiber membrane filter according to an embodiment according to the first aspect. In particular, in further procedure steps, for example, a sealing ring for axial and / or radial sealing is inserted outside the support ring in a position provided for this purpose.

[0039] In a third aspect, the present invention relates to the use of a support ring 117 for the construction of a hollow fiber membrane filter, comprising a circumferential sidewall 118 having an outer surface 119, an inner surface 120, an upper edge 121, and a lower edge 122, and a circumferential protrusion 123 arranged at the upper edge 121 protruding from the outer surface 119 of the circumferential sidewall 118. Preferably, a support ring is used which additionally has a circumferential groove 126, 128 for receiving a sealing ring which seals radially or axially against the outer side 119 or the protrusion 123 of the circumferential sidewall 118. More preferably, a support ring is used where the support ring is conically formed at least per section on the inner side 120 of the circumferential sidewall 118 in the direction from the upper edge 121 to the lower edge 122.

[0040] Working Example Production of hollow fiber membrane filters according to the present invention In a cylindrical filter housing of the type HF80S available from Fresenius Medical Care Deutschland GmbH, a support ring is inserted into each end portion of the cylindrical housing as shown in FIG. 3b with the sealing rings sealing axially recessed into the grooves extending circumferentially along the projections. The cylindrical housing is made of polycarbonate and the support rings are made of polypropylene. The support rings have the dimensions (in mm) shown in FIG. 3b. The inner surface of the support ring is chemically modified by corona treatment. A hollow fiber membrane bundle wrapped in an envelope film encasing about 12,300 hollow fiber membranes, each having a double corrugated texture with an inner diameter of 200 μm, a wall thickness of 40 μm, and wavelengths of 30 and 3 mm, produced as described in Example 1 of EP 3 423 173 A1, was inserted into the cylindrical housing through the support ring. A further production of hollow fiber membrane filters was carried out according to known methods and process steps. 109 g of polyurethane was used per filter for embedding, the effective length of the hollow fibers (the length of the hollow fiber membrane between the embedded ends) was 230 mm, and a hollow fiber membrane filter was obtained in which the structure of each end portion corresponds to the filter shown in Figure 1.

[0041] Comparative Example The comparative filter was manufactured in the same manner as the filter described above, but without the installation of the support ring. The hollow fiber membrane was cast directly into the filter housing using conventional methods.

[0042] Thermal Stress Test The hollow fiber membrane filters manufactured according to the above Working Examples and the hollow fiber membrane filters manufactured according to the Comparative Examples were subjected to a thermal stress test. Stage 1: For this purpose, the hollow fiber membrane filter is connected to the blood side and dialysate side medium supply devices through two connections each in a vertical direction. The hollow fiber membrane filter is treated from above with pure steam and an absolute pressure of 2.35 bar and a temperature of 125° C. for 17 minutes. The exposure time is recorded by adding pure steam. Phase 2: After the exposure to steam in phase 1, the exposure is switched to ultrapure water (HPW) and the ultrapure water is set at a temperature of 95° C. The blood side and the dialysate side are exposed to an absolute pressure of 3.2 bar for 5 minutes and 20 seconds. The exposure time is recorded as ultrapure water is added. Phase 3: After this phase, the dialysate side is emptied and filled with sterile air at a pressure of 2.8 bar absolute. The blood side water is cooled to 54°C and it is observed whether air passes through the blood side water. For this purpose, an inspection window with an outer diameter of 15 mm, an inner diameter of 10 mm and a sampling length of 65 mm is installed in the water supply. The inspection window is monitored by a digital camera and the number of bubbles, the size of each bubble and the size of all bubbles are calculated. This procedure is known as the "bubble test". The measurement is carried out for 15 seconds. A minimum of 1.7 mm 2 7 bubbles with an area of ​​1.7 mm 2 There is one bubble with an observed area greater than 34 mm2, or the total observed area of ​​all detected bubbles is 34 mm2. 2 The experiment was stopped if the measured value exceeded 4. Measurements were performed in sequence, and the hollow fiber membrane filter was assessed as leaking if any one of the measurements reached the endpoint criteria described above. Stage 4: After the air bubble test, sterile dry air is applied for 25 minutes at a temperature of 110° C. and an absolute pressure of 1.7 bar (blood side), 1.5 bar (dialysate side). If the above-mentioned air bubble test does not reveal any leaks, the test is counted as one cycle. A hollow fiber membrane filter that is leaking from the beginning would therefore be assigned cycle number 0, and a hollow fiber membrane filter that is defective in the third cycle would therefore be assigned cycle number 2. Four hollow fiber membrane filters were tested according to Example 1. The cycle numbers obtained were 30, 30, 13, 30. The experiment was terminated after 30 successful cycles. Six comparative hollow fiber membrane filters were tested. The determined cycle numbers were 8, 8, 2, 2, 2, and 8. As can be seen, embodiments in accordance with the present invention are significantly more resilient than embodiments not incorporating the features of the present invention. [Explanation of symbols]

[0043] 108 Hollow fiber membrane 109 Embedded Mass 117 Support Ring 123 Circumferential projection 127 Sealing Ring

Claims

1. a cylindrical housing (101) extending longitudinally along a central axis (A) and having an inside (102), an outside (103), a housing interior (104), a first end portion (105) having a first terminal edge (106), and a second end portion having a second terminal edge; at least a first fluid port (107) disposed at the first end portion of the cylindrical housing, and an optional second fluid port disposed at the second end portion of the cylindrical housing; a plurality of hollow fiber membranes (108) disposed in the cylindrical housing (101) and sealingly embedded in embedding masses (109) within the first end portion (105) and the second end portion of the cylindrical housing (101), the hollow fiber membranes having open ends (110) such that the lumens of the hollow fiber membranes form a first flow space and the housing interior (104) surrounding the hollow fiber membranes forms a second flow space; first and second end caps (111) having an interior and an exterior, the end caps being face-side connected to the first (105) and second end portions of the cylindrical housing (101), respectively, to form respective inlet or outlet chambers (114) in fluid communication with the first flow space of the hollow fiber membrane filter, the first and second end caps (111) or the cylindrical housing having respective third and fourth fluid access ports (115) for supplying or discharging fluid to or from the first inlet or outlet chambers (114); at least first (116) and second sealing rings, each sealingly disposed between a respective potting compound (109) and the interior (112) of a respective said end cap (111), laterally sealing said respective inlet and outlet chambers (114); at least first and second support rings (117) including a circumferential sidewall (118) having an outer side (119) and an inner side (120), an upper edge (121), and a lower edge (122), the at least first and second support rings (117) being disposed in each of the first and second end portions (105) of the cylindrical housing such that the outer side (119) of each support ring (117) faces the inner side of the cylindrical housing (102) within the respective end portion (105); A hollow fiber membrane filter comprising: each said support ring (117) has a circumferential protrusion (123) disposed on said upper edge (121) and projecting beyond said outer side (119) of said circumferential side wall (118) of said respective support ring (117), said circumferential protrusion (123) resting on said terminal edge (106) of said first and second end portions (105) of said cylindrical housing (101), and each said embedding mass (109) being at least partially disposed in a liquid-tight manner in an edge region (124) between said circumferential protrusion (123) of said respective support ring (117) and said sealing ring; Hollow fiber membrane filters.

2. 2. The hollow fiber membrane filter according to claim 1, wherein the embedding mass (109) has the shape of a flange (125) at its edge region (123) resting on the protrusion (123) of the support ring (117) and arranged between the embedding compound (109) and the sealing ring (116).

3. 3. The hollow fiber membrane filter of claim 1, wherein a radially sealing ring is disposed between the outer side (119) of the circumferential side wall (118) of each support ring (117) and the inner side (102) of the cylindrical housing in each end portion (105).

4. 4. The hollow fiber membrane filter of claim 3, wherein the support ring (117) on the outer side (119) of the circumferential side wall (118) facing the inner side (102) of the cylindrical housing (101) in each end portion (105) has a circumferential groove (126) into which the radially sealing sealing ring is at least partially recessed.

5. 3. The hollow fiber membrane filter of claim 1, wherein an axially sealing sealing ring (127) is disposed between the projection (123) of each support ring (117) and the respective terminal edge (126) of each end portion (105).

6. 3. The hollow fiber membrane filter according to claim 1, wherein the support ring (117) has, on the side of the projection (123) facing the terminal edge (126) of each end portion (105), a circumferential groove (128) into which the axially sealing ring (127) is at least partially recessed.

7. 3. The hollow fiber membrane filter according to claim 1, wherein the support ring (117) has a circumferential undercut (129) at the transition from its circumferential side wall (118) to the protrusion (123) on the outer side (119).

8. 3. The hollow fiber membrane filter according to claim 1, wherein the circumferential sidewall (118) of the support ring (117) on the inner side (120) of each of the support rings is conically shaped at least in sections from the upper edge (121) to the lower edge (122).

9. 9. The hollow fiber membrane filter of claim 8, wherein the circumferential sidewall (118) of the support ring on the inner side (120) has at least zones I and II, and zones I and / or II are conically shaped, or at least zone I or II is cylindrically shaped and zone II or I is conically shaped.

10. 10. The hollow fiber membrane filter according to claim 9, wherein at least one of the conically shaped zones I or II has a cone angle of 3 to 15 degrees relative to the direction of the central axis (A).

11. 10. The hollow fiber membrane filter of claim 9, wherein at least the edges (121a, 122a, 130) of the support ring (117) present on the inner side (119) of the circumferential side wall (118) are rounded.

12. A method for manufacturing the hollow fiber membrane filter of claim 1 or claim 2, comprising: providing a cylindrical housing (101) having an inside (102), an outside (103), a housing interior (104), a first end portion (105) having a first terminal edge (106), and a second end portion having a second terminal edge, the cylindrical housing (101) extending longitudinally along a central axis (A); providing two support rings (117), each having a circumferential sidewall (118) including an outer side (119) and an inner side (120), an upper edge (121) and a lower edge (122), and a protrusion (123) located on the upper edge (121) of the respective support ring (117) and protruding beyond the outer side (119) of the circumferential sidewall (118) of the respective support ring (117); inserting the support rings (117) into each of the end portions (105) of the cylindrical housing (101) such that the support rings (117) are disposed in each of the first and second end portions (105) of the cylindrical housing, the outer side (119) of each support ring (117) facing the inner side (102) of the cylindrical housing in its respective end portion (105), and each support ring (117) resting with the circumferential projections (123) disposed on the upper edges (121) on the terminal edges (106) of each of the first and second end portions (105) of the cylindrical housing (101); Inserting a hollow fiber membrane bundle consisting of a plurality of hollow fiber membranes into the cylindrical housing (101) and into each of the support rings; embedding the ends of the hollow fiber membranes with their respective support rings (117) in an embedding zone with an embedding mass (109); mounting end caps (111) onto the respective end portions (105) of the cylindrical housing (101) while inserting sealing rings (116) between the inside (112) of the end caps (111) and the edge areas (124) of the embedding mass (109); A method comprising:

13. Use of a support ring (117) including a circumferential sidewall (118) having an outer surface (119), an inner surface (120), and upper (121) and lower (122) edges, and a circumferential protrusion (123) disposed on the upper edge (121) and protruding beyond the outer surface (119) of the circumferential sidewall (118) for the construction of a hollow fiber membrane filter.

14. 14. Use of a support ring (117) according to claim 13, wherein the support ring has a circumferential groove (126, 128) on the outer side (119) of the circumferential side wall (118) or on the projection (123).

15. 15. Use of a support ring (117) according to claim 13 or claim 14, wherein the support ring (117) is formed on the inner side (120) of the circumferential side wall (118) in the shape of a cone at least per section in the direction from the upper edge (121) towards the lower edge (122).

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