Infusion filter

Abstract

The present invention relates to an infusion filter (14; 114; 514; 1014; 1114; 1214) designed to filter out particles and / or bacteria and / or endotoxins and / or fungi from an infusion liquid and to separate air contained in the infusion liquid, the infusion filter comprising a housing (24) which extends from an input region (20) extends to an output region (22) along a longitudinal axis (21), wherein: a filter membrane (26; 126; 226; 326; 426; 526; 626; 726; 826; 926; 1026; 1126; 1226; 1326; 1426; 1526; 1626; 1726) is arranged in the housing (24) and is designed to filter out the particles and / or bacteria and / or endotoxins and / or fungi from the infusion liquid; an input-side venting membrane ring (34a) is arranged in the input region (20); and an output-side venting membrane ring (36a) is arranged in the output region (22); both venting membrane rings (34a, 36a) are hydrophobic and connect an interior of the housing (24) to the surroundings, as a result of which the venting membrane rings are designed for (position-independent) separation of air contained in the infusion liquid during priming and during therapy; both ventilation membrane rings (34a, 36a) are disk-like, in particular annular, and revolve around the longitudinal axis (21). The invention also relates to: an infusion set (6) comprising an infusion filter (14; 114; 514; 1014; 1114; 1214) and a tube (12, 16); and an infusion device (2) having an infusion set (6), an infusion container (4) and an infusion access (8). Finally, the invention relates to a method for producing such infusion filters (14; 114; 514).

Description

[0001] Infusion filter

[0002] Description

[0003] The present disclosure relates to an infusion filter designed to filter out particles and / or bacteria and / or endotoxins and / or fungi from an infusion fluid (or infusion solution) and to separate air contained in the infusion fluid. The disclosure also relates to an infusion set or infusion system comprising an infusion filter and tubing. Furthermore, the disclosure relates to an infusion device comprising an infusion set, an infusion container, and an infusion access point. Finally, the disclosure relates to a method for manufacturing an infusion filter.

[0004] State of the art

[0005] It is known that up to ten million minute particles are infused daily into (intensive care) patients during intravenous infusion therapy if the infusion fluid or solution is not filtered before administration. These particles include, for example, plastic debris from ampoules, infusion bottles, or disposable syringes; glass fragments from broken-neck ampoules; and salt or drug precipitates that form when different infused medications are incompatible. Furthermore, the risk of bacteria, endotoxins, or fungi being infused during intravenous infusion therapy is also well-known.

[0006] It is generally known from the prior art to integrate infusion filters or in-line filters into an infusion set / infusion system and thus into the infusion line. If such an infusion filter is positioned as close as possible to the patient, the introduction of particles, bacteria, endotoxins, or fungi can be significantly reduced, and preferably almost completely prevented. These infusion filters have filter membranes that can effectively capture or filter out even the smallest particles (larger than 0.2 pm for aqueous solutions or larger than 1.2 pm for lipid solutions) and / or bacteria and / or endotoxins and / or fungi. Furthermore, infusion filters remove air (bubbles), thus protecting the patient from unwanted air inhalation during infusion therapy.

[0007] A well-known infusion filter, for example, has a polycarbonate housing containing a microporous flat membrane. For venting, the housing has one or more holes, such as two, which are sealed with an air-permeable but fluid-impermeable hydrophobic membrane. The infusion filter also has a fluid inlet and a fluid outlet. The infusion fluid can thus flow into the infusion filter through the fluid inlet and is filtered by the microporous flat membrane. Air is separated by the hydrophobic membrane.

[0008] After the infusion fluid has been filtered through the microporous flat membrane and the air contained in the infusion fluid has been removed or separated by the hydrophobic membrane, the infusion fluid flows out of the infusion filter via the fluid outlet and can be infused into the patient. One such infusion filter is, for example, the Sterif ix® infusion filter of the applicant in the present patent application.

[0009] The previously described infusion filter, due to its use of a flat membrane, requires a relatively large two-dimensional extent to provide a sufficient filter surface area to meet the performance requirements of the membrane (pressure drop). A large filter surface area is necessary to achieve the required flow rates. When such an infusion filter is connected to tubing in an infusion system or infusion set, its longitudinal extent typically follows the axial extent of the tubing. However, the width of the infusion filter is usually significantly greater than the diameter of the tubing, causing the filter to protrude considerably in the radial direction relative to the tubing's cross-section.Against this background, if the infusion filter is positioned close to the patient in the infusion system / setup, there is a risk that the filter could become caught or snagged on a hospital bed or bedside table, thus exerting a pulling force on the infusion set when the patient moves. If this pulling force is applied to the infusion set, there is a risk that an infusion access device, such as an IV needle or catheter, could be pulled out of the patient's vein, potentially leading to injury and blood loss. There is also a risk that the infusion set could be pulled out of an IV container. Even the possibility of an IV stand being knocked over cannot be ruled out.

[0010] Another disadvantage is the position-dependent venting function (especially during priming) of infusion filters known from the prior art. Since there are usually only one or two small venting openings on one side of the filter, complete venting of the filter depends on its position.

[0011] GB 2 153247 A discloses a filter device for infusion fluids. The filter device has a cylindrical housing through which the infusion fluid flows. The housing is designed with two sections, one of which is hydrophobic and therefore permeable to air, and the other of which is non-hydrophobic. Furthermore, an inner filtration membrane made of impregnated, and therefore hydrophilic, hollow fibers is provided within the housing for filtering the infusion fluid. The filtration membrane is composed of U-shaped fibers or, according to another embodiment, of individual longitudinal fibers. The fiber ends in the filtration membrane are closed towards an inlet of the housing and open towards an outlet of the housing. The fiber ends are embedded so that filtered infusion fluid exits the closed end of the filtration membrane.The inlet is designed as an inlet opening and the outlet as an outlet opening for infusion fluid, at which end caps are arranged that form housing parts of the filter device. DE 3304951 A1 discloses a filter device through which an infusion fluid flows, wherein the one-piece housing is gas-permeable and liquid-impermeable. A hydrophilic liquid filter element is arranged in the housing shell, which is designed for sterile filtration or particle filtration and is bacteria-tight. It can be implemented as a wettable and thus liquid-permeable and gas-impermeable microporous filter membrane and, in particular, via an arrangement of porous, wettable hollow filaments. The hollow filaments are embedded with their open ends in a potting block, which, depending on the flow direction of the infusion fluid, can be located at the outlet of the housing.At one end, facing away from the potting compound block and representing the inlet, the hollow threads are sealed to prevent liquid buildup.

[0012] Currently available or known infusion filters do not offer a position-independent venting function (360° venting) during initial filling or priming. Therefore, users must position the infusion filter in a specific way during the filling process to ensure complete filling. If the infusion filter is filled (for the first time) in a position other than the specified one, it may not be fully wetted, allowing air to pass through the filter membrane and into the patient, potentially leading to an air embolism.

[0013] Brief description of the Revelation

[0014] Against this background, the purpose of this disclosure is to provide an infusion filter that filters out particles, bacteria, endotoxins, and / or fungi from an infusion fluid or infusion solution. The infusion filter should have a shape and size that prevents snagging or sticking, thus increasing patient safety. At the same time, the infusion filter should have a filter membrane with a sufficient filter area. Air contained in the infusion fluid should be separated regardless of its position. In particular, a position-independent venting function (360° venting) should be ensured during priming, as per BB2580P-WG-0004.

[0015] 5 / 39

[0016] Users do not need to position the infusion filter specifically during the filling process to achieve complete filling. Regardless of its position, the filter should be wetted, preventing air from passing through the filter membrane into the patient and thus reliably preventing air embolism.

[0017] These tasks are accomplished by an infusion filter according to claim 1, an infusion set or infusion system according to claim 20, an infusion device according to claim 21, and a method for manufacturing an infusion filter according to claim 23. Advantageous embodiments and further developments are claimed in the dependent claims and / or are explained below.

[0018] The infusion filter as disclosed is designed to filter out particles and / or bacteria and / or endotoxins and / or fungi from an infusion fluid and to separate air contained in the infusion fluid, particularly regardless of its orientation. It has a housing that is cylindrical, preferably circular, at least in the region of a central main section. The housing extends from an inlet area to an outlet area along a longitudinal axis. A filter membrane is arranged within the housing, which is designed to filter out the particles and / or bacteria and / or endotoxins and / or fungi from the infusion fluid. An inlet-side venting membrane ring is arranged in or at the inlet area, while an outlet-side venting membrane ring is arranged in or at the outlet area.Both venting membrane rings are hydrophobic and connect an interior space of the housing to the environment, thus enabling the separation, particularly independent of position, of air contained in the infusion fluid, especially during priming and / or therapy. Both venting membrane rings are disc-shaped and rotate around their longitudinal axis. The infusion filter as disclosed achieves 360° venting of the infusion filter, more precisely of the infusion fluid inside the infusion filter. This allows for targeted, position-independent venting of the infusion fluid inside the infusion filter. Specifically, the infusion filter as disclosed achieves 360° BB2580P-WG-0004.

[0019] 6 / 39

[0020] The venting function enables and thus prevents incorrect use during priming and air embolism.

[0021] Due to the design of the venting membrane rings that rotate around the longitudinal axis, the current rotational position of the infusion filter is irrelevant for the venting function.

[0022] Thanks to the venting membrane rings on both sides, the (current) inclination of the infusion filter's longitudinal axis is irrelevant to the venting function. It is therefore immaterial whether the longitudinal axis rises or falls from the inlet to the outlet. In summary, the aforementioned venting is achieved regardless of the filter's position in the room.

[0023] The closer the two venting membrane rings are to the absolute ends of the infusion filter's interior space that receives the infusion fluid, or the further apart the two venting membrane rings are along the longitudinal axis, the more complete the venting function is, regardless of the position (inclination of the longitudinal axis) of the infusion filter.

[0024] In a preferred assembly design, the housing is divided into three parts. The housing has an inlet-side connector forming the inlet area and an outlet-side connector forming the outlet area. Both connectors are spaced apart from each other along the longitudinal axis and attached to a main part of the housing. The inlet-side venting membrane ring is positioned and sealed between the inlet-side connector and the main part. Similarly, the outlet-side venting membrane ring is positioned and sealed between the outlet-side connector and the main part. The housing can also be one-piece, two-piece, or four-piece, or even comprise more than four parts.

[0025] In other words, the infusion filter preferably has a first connector, in particular with a Luer-lock connection or with bonding to the tubing, at a first axial end of the cylindrical housing and a second connector, BB2580P-WG-0004

[0026] 7 / 39

[0027] in particular with a Luer-lock connection or with bonding to the hose, at a second axial end of the cylindrical housing. The two connecting pieces are preferably aligned in a longitudinal direction of the cylindrical main part or extend axially away from the cylindrical main part.

[0028] Due to its cylindrical outer shape, preferably without steps in the three-part housing, the infusion filter is preferably adapted to the outer shape of an (infusion) tube to be connected to the infusion filter and, in its intended use, preferably follows the tube, i.e., preferably represents an axial extension of the tube. Such an outer shape or design of the infusion filter greatly reduces points of snagging or entanglement, thus increasing patient safety.

[0029] In other words, this prevents sections of the infusion filter from extending radially away from the cylindrical housing. This also makes it unlikely that the connecting pieces will snag or get caught on the hospital bed or bedside table, thus increasing patient safety.

[0030] It is particularly preferred if the two connecting pieces form, for example, injection-molded end caps that are dome-shaped or cup-shaped, and each has an axial (disc-like) contact surface circumferentially around the longitudinal axis for the respective venting membrane ring. A centering rim for the main part and / or for the respective venting membrane ring is arranged on the outer circumference of each contact surface. The central main part then has a corresponding inlet-side end face and an outlet-side end face, each with an axial (disc-like) contact surface circumferentially around the longitudinal axis for the respective venting membrane ring. Each venting membrane ring is thus arranged between the contact surface of the respective connecting piece and one of the two contact surfaces of the main part, in particular clamped in a sealing manner and / or welded to the connecting piece.Preferably, the venting membrane rings are first firmly connected to the connecting piece, in particular welded, andBB2580P-WG-0004.

[0031] 8 / 39

[0032] The respective assembly consisting of the connecting piece and the venting membrane ring is then connected to the main part.

[0033] The mounting surface of each connector has (evenly distributed) passage recesses that connect the respective venting membrane ring to the environment.

[0034] The two connecting pieces (e.g., end caps) can be designed differently to optimally adapt to the varying conditions of the inlet and outlet areas. Alternatively, the two connecting pieces (e.g., end caps) can be identical, which simplifies the manufacturing and assembly of the infusion filter.

[0035] In particular, the 360° venting of the infusion filter, or more precisely the infusion fluid inside the infusion filter, is achieved by the two hydrophobic venting membrane rings located at the connecting pieces (end caps) of the inlet and outlet areas. This allows for targeted, position-independent venting of the infusion fluid inside the infusion filter.

[0036] The outlet-side mounting surface of the main part may also have (evenly distributed) through-holes that connect the interior to the outlet-side venting membrane ring. The outlet-side through-holes of the main part should coincide with and / or be aligned with the through-holes of the outlet-side connecting piece.

[0037] In a particularly preferred embodiment, the infusion filter is rotationally symmetrical. In the case of a three-part housing, the main part, the two connecting pieces, and the two venting membrane rings are rotationally symmetrical about the longitudinal axis. Thus, the main part of the housing is cylindrical, and the two venting membrane rings are circular disks. BB2580P-WQ-0004

[0038] 9 / 39

[0039] In the further development with the contact surfaces, these are, in the case of rotational symmetry, circular ring disks, i.e., internally open, ring-shaped circular disks. In the further development with the centering edges, these are, in the case of rotational symmetry, centering rings. In the further development with the through-holes, these are preferably arc-shaped in the case of rotational symmetry.

[0040] Preferably, the outer radius or the mean radius of the venting membrane rings corresponds approximately to the inner radius of the main part of the housing. This optimizes the independence of the infusion filter's longitudinal axis from any inclination, even when the longitudinal axis is horizontally oriented.

[0041] In the further development with the outlet-side through-holes of the main part, these have radially outer edges whose radius (with respect to the longitudinal axis) corresponds to that of the inner shell of the main part. This ensures optimal transfer of air bubbles from the inner shell of the main part to its through-holes, and thus optimal venting, even in the case of a horizontal orientation of the longitudinal axis.

[0042] Preferably, the filter membrane has a multitude of holes / openings / perforations / pores. These are preferably arranged in the filter membrane to allow the infusion fluid to flow through the filter membrane while simultaneously filtering out particles / bacteria / endotoxins / fungi.

[0043] Preferably, the filter membrane is designed as a microporous membrane with a pore size of 0.1 pm to 20 pm, in particular only from 0.2 pm to 1 pm or for lipid solutions up to 1.2 pm, and is thus optimally suited for filtering out particles and bacteria.

[0044] Preferably, the filter membrane is positively charged and therefore ideal for filtering out endotoxins. A positively charged filter membrane can be achieved, for example, by polymerization or coating with a layer of positively charged ions. The filter membrane is preferably made of a hydrophilic plastic.

[0045] In particular, it has proven advantageous to use a hydrophilic thermoplastic such as polysulfone, polyethersulfone, or polyamide. A hydrophilic thermoset can also be used. If the filter membrane has these hydrophilic properties, it can act as an air brake, thus helping air to escape more easily from the infusion filter via the venting membrane rings.

[0046] Preferably, the holes / openings / perforations / pores provided in the filter membrane are produced using a wet spinning process. Preferably, a hydrophilic pore-forming agent, rather than a hydrophobic one, is used in the production of the filter membrane. Polyvinylpyrrolidone (PVP) has proven particularly advantageous as a hydrophilic pore-forming agent.

[0047] It can therefore be stated that, depending on the size of the pores of the filter membrane, the charge of the filter membrane and the material used for the filter membrane, the filter membrane can be functionally designed as a particle filter and / or bacteria filter and / or endotoxin filter and / or air filter or air brake, etc.

[0048] In one embodiment, the filter membrane is designed as a capillary membrane with a bundle of hollow fibers. The first axial end of the capillary membrane has closed ends of its hollow fibers, while the second axial end has open ends. The second axial end of the capillary membrane is embedded in an adhesive matrix, so that the infusion fluid initially flows into the spaces between the hollow fibers of the capillary membrane at the first axial end, and then flows completely through the walls of the hollow fibers into the hollow fibers, where it is filtered. Only filtered infusion fluid exits the open ends of the hollow fibers and then flows out at the outlet of the infusion filter housing.The hollow fibers of the capillary membrane are inserted and sealed into an embedding pot attached to or integrally formed with the housing in an intermediate manufacturing stage at the housing's outlet area. Therefore, in exemplary embodiments of the infusion filter with capillary membrane, part of the embedding pot may remain attached to the final product.

[0049] In another embodiment, the filter membrane can be cylindrical in shape and the infusion fluid can flow through it radially from the outside to the inside.

[0050] Depending on its rigidity, the filter membrane can be attached to an inner support cage.

[0051] An increased filter area can be achieved if the filter membrane is formed from two circular cylindrical sections that are concentric to each other, with a space for filtered infusion fluid formed between the two sections.

[0052] Another embodiment also has an inner and an outer cylindrical filter membrane, which, however, are separated by a cylindrical separator. In this way, filtration for both cylindrical filter membranes takes place from their respective outer surfaces to their respective inner surfaces.

[0053] A particularly large filter area can be achieved if the filter membrane is formed from two adjacent walls, between which a flat space for filtered infusion fluid is formed, with the two walls and the space formed between them being arranged (wound) in a spiral around the longitudinal axis.

[0054] To increase the filter area of ​​a single, essentially cylindrical filter membrane, it can be designed as a bellows with edges that circumferentially wrap around the longitudinal axis. In this case, radially inner and radially outer edges alternate, resulting in a zigzag shape in longitudinal section, for example. BB2580P-WQ-0004

[0055] 12 / 39

[0056] Particularly in the case of further development as a bellows, the filter membrane can be fluid-tightly connected to an inlet-side support ring or support pot via a welded connection and to an outlet-side support ring via another welded connection.

[0057] In its further development as a bellows, it can be held by a support cage which, viewed along the longitudinal axis, alternately has radially inner support sections and radially outer support sections.

[0058] In another, differing embodiment, the filter membrane, viewed in longitudinal section, can be meandering or formed as a sequence of sections arranged at angles to one another. This filter membrane is attached to the inner side of the main housing part by means of an inlet-side weld and an outlet-side weld. If the two welds are located on opposite sides of the inner side of the main part, the outlet-side weld can axially define an inlet space and the inlet-side weld can define an outlet space within the interior of the main part.

[0059] In other, differing embodiments, the filter membrane is cross-shaped or star-shaped in cross-section. The larger and more numerous the radially projecting lamellae formed in this way, the larger the filter area.

[0060] For a large number of smaller louvers, these are preferably supported by an inlet-side and an outlet-side support element. For fewer than ten louvers, a support structure may be provided, comprising several webs extending parallel to the longitudinal axis.

[0061] In another differing embodiment, the filter membrane has several pairs of inlet-side sections and outlet-side sections, wherein the sections are frustoconical and concentric to the longitudinal axis. Each pair of sections forms an internal, also frustoconical, space for the filtered infusion fluid, which is then collected in a central longitudinal tube. In yet another differing embodiment, the filter membrane is a hollow body extending along the longitudinal axis and composed of a preferably cuboid central section and several preferably cuboid longitudinal ribs. The central section and the longitudinal ribs together define an interior space for the filtered infusion fluid. The central section has an outlet for the filtered infusion fluid.

[0062] The disclosure further relates to an infusion set or infusion system comprising: a cylindrical infusion filter as described above, a first tube connected to a first axial end of the cylindrical infusion filter, and a second tube connected to a second axial end of the cylindrical infusion filter (opposite the first axial end in the axial direction).

[0063] When an infusion set is designed in this way, a tube-like infusion filter integrates optimally into it and essentially represents an extension of the first and second tubes. In other words, the infusion filter, the first tube, and the second tube are preferably arranged, or can be arranged, coaxially. This is preferably achieved by connecting the tubes to the axial ends of the cylindrical housing.

[0064] The infusion set or infusion system preferably includes further elements or components such as additional tubing, a connection to an infusion container, a connection to an infusion access, a flow regulator, etc.

[0065] Furthermore, the present disclosure relates to an infusion device comprising an infusion set or infusion system as described above, an infusion container (e.g., infusion bag), and an infusion access (e.g.,

[0066] Infusion needle, infusion catheter), wherein the infusion set connects the infusion container to the infusion access. Preferably, the second tube of the infusion set, which connects the infusion filter to the infusion access, is very short (less than 20 cm, preferably less than 10 cm) so that the infusion filter is positioned as close to the patient as possible.

[0067] The infusion device preferably includes further elements or components such as a syringe, a pump, an infusion stand, etc.

[0068] The disclosed method is used to manufacture, preferably, a previously described infusion filter, comprising the steps

[0069] - Manufacturing a main part of a housing with an embedding pot formed integrally with it or attached to it (formed and formed as a separate component), wherein the main part and the embedding pot preferably extend along a common longitudinal axis;

[0070] - Embedding an end section of a hollow fiber bundle in the embedding pot using adhesive, wherein the end sections of the hollow fibers of the hollow fiber bundle are surrounded by the adhesive, and wherein the adhesive seals the end section of the hollow fiber bundle against the embedding pot;

[0071] - Forming end-face hollow fiber openings, which are sealed by adhesive, by separating an outer part of the embedding pot, including the portion of the end section of the hollow fiber bundle arranged therein and the portion of the adhesive surrounding that portion of the end section. Preferably, the separation results in a (cut) surface transverse to the longitudinal axis.

[0072] In a particularly preferred embodiment of the method, following the aforementioned steps, an inlet-side venting membrane ring and an inlet-side connector are mounted to the main part, as is an outlet-side venting membrane ring and an outlet-side connector. Preferably, the inlet-side venting membrane ring is mounted by attaching the inlet-side connector to the main part, and the outlet-side venting membrane ring is mounted by attaching the outlet-side connector to the main part. The venting membrane rings can first be permanently connected (welded) to the respective connector / part before being connected to the main part. This allows for targeted, position-independent venting of the infusion fluid inside the infusion filter.

[0073] In particular, the infusion filter manufactured according to the disclosure enables a 360° venting function, thus preventing incorrect use during priming and air embolism.

[0074] Thanks to the venting membrane rings on both sides, the current inclination of the infusion filter's longitudinal axis is irrelevant to the venting function. It is therefore immaterial whether the longitudinal axis rises or falls from the inlet to the outlet. This further improves the venting function and prevents air embolism.

[0075] Brief description of the characters

[0076] The revelation is further explained below with the help of figures. They show:

[0077] Figure 1 shows a schematic view of an infusion device as disclosed;

[0078] Figure 2a shows an embodiment of an infusion filter according to the disclosure in an exploded view;

[0079] Figure 2b shows the embodiment from Figure 2a in a view against the flow direction of the infusion fluid;

[0080] Figure 3a shows a further embodiment of an infusion filter according to the disclosure in a side view;

[0081] Figure 3b shows the embodiment from Figure 3a in a longitudinal section;

[0082] Figure 3c shows an entrance area of ​​the embodiment from Figure 3a in a further perspective longitudinal section; Figure 3d shows an exit area of ​​the embodiment from Figure 3a in a further perspective longitudinal section;

[0083] Figure 4 shows an embodiment of a filter membrane designed as a hollow fiber bundle, in an intermediate stage of its manufacture;

[0084] Figure 5 shows another embodiment of a filter membrane designed as a hollow fiber bundle, in an intermediate stage of its manufacture;

[0085] Figure 6 shows another embodiment of a filter membrane designed as a hollow fiber bundle, in an intermediate stage of its manufacture;

[0086] Figure 7 shows another embodiment of a filter membrane designed as a bundle of hollow fibers, in an intermediate stage of its manufacture;

[0087] Figure 8 shows another embodiment of a filter membrane designed as a hollow fiber bundle, in an intermediate stage of its manufacture;

[0088] Figure 9a shows a further embodiment of an infusion filter according to the disclosure in an exploded view;

[0089] Figure 9b shows an alternative support cage for the embodiment shown in Figure 9a;

[0090] Figure 10 shows another embodiment of a filter membrane;

[0091] Figure 11 shows another embodiment of a filter membrane;

[0092] Figure 12 shows another embodiment of a filter membrane;

[0093] Figure 13 shows a further embodiment of a filter membrane in a sectional view; Figure 14 shows a further embodiment of an infusion filter according to the disclosure in a schematic sectional view;

[0094] Figure 15 shows a further embodiment of an infusion filter according to the disclosure in an exploded view;

[0095] Figure 16 shows a further embodiment of an infusion filter according to the disclosure in an exploded view;

[0096] Figure 17a shows another embodiment of a filter membrane in one view;

[0097] Figure 17b shows the filter membrane from Figure 17a in a further view;

[0098] Figure 18 shows another embodiment of a filter membrane;

[0099] Figure 19 shows another embodiment of a filter membrane;

[0100] Figure 20 shows another embodiment of a filter membrane;

[0101] Figure 21a shows another embodiment of a filter membrane in one view;

[0102] Figure 21b shows the filter membrane from Figure 21a in another view;

[0103] Figure 22 shows a main part of a housing of an infusion filter according to the disclosure with a first embodiment of an embedding pot in a view;

[0104] Figure 23 shows a main part of a housing of an infusion filter according to the disclosure with a second embodiment of an embedding pot in a view;

[0105] Figure 24a shows a main part of a housing of an infusion filter according to the disclosure with a third embodiment of an embedding pot in a view; Figure 24b shows the main part with the third embodiment of an embedding pot from Figure 24a in a sectional side view; and

[0106] Figure 25 shows a flowchart of an exemplary embodiment of the method for manufacturing an infusion filter.

[0107] Character description

[0108] The figures are purely schematic and serve solely to aid in understanding the present revelation. Identical elements are marked with the same reference symbols.

[0109] Figure 1 shows a schematic view of an infusion device 2. The infusion device 2 comprises an infusion container (infusion bag) 4, an infusion set or infusion system 6, and an infusion access (infusion needle, infusion catheter) 8. The infusion set 6 connects the infusion container 4 to the infusion access 8. An infusion fluid can therefore be administered to a patient from the infusion container 4 via the infusion set 6 and the infusion access 8.

[0110] The infusion set 6 comprises at least one infusion container connection 10, a first tube 12, an infusion filter 14; 114; 514; 1014; 1114; 1214, a second tube 16, and an infusion access port 18. It is understood that further elements, such as additional tubes, additional connections, a flow regulator, a gravity pump, or other pumps, etc., may be provided or are already included.

[0111] The infusion container port 10 is prepared and configured to be connected to the infusion container 4, and the infusion access port 18 is prepared and configured to be connected to the infusion access port 8. The infusion container port 10 is located at one end of the first tube 12, and the infusion access port 18 is located at one end of the second tube 16. As can already be seen in Figure 1, the infusion filter 14; 114; 514; 1014; 1114; 1214 is cylindrical and thus tube-like. The first tube 12 is connected to a first axial end 20 of the infusion filter 14. The second tube 16 is connected to a second axial end 22, which is opposite the first axial end 20.The infusion filter 14; 114; 514; 1014; 1114; 1214 is substantially adapted in shape and size (radial extent) to the first tube 12 and the second tube 16 and can preferably extend coaxially to the first tube 12 and the second tube 16. The infusion filter 14; 114; 514; 1014; 1114; 1214 thus forms an extension of the first tube 12 and the second tube 16.

[0112] Figure 1 also shows that the second tube 16 is very short so that the infusion filter 14; 114; 514; 1014; 1114; 1214 can be positioned as close as possible to the patient, thus reducing the risk of particle detachment and ingress into the patient downstream of the infusion filter 14.

[0113] The infusion filter 14; 114; 514; 1014; 1114; 1214 has a three-part (hollow) cylindrical housing and a filter membrane arranged therein, details and embodiment of which are explained in the following figures.

[0114] Figure 2a shows a first embodiment of the infusion filter 14 according to the disclosure in an exploded view, while Figure 2b shows the infusion filter 14 from Figure 2a in a view against the flow direction of the infusion fluid.

[0115] A first connecting piece 34 is arranged at the first axial end 20 of the infusion filter 14 or of a main part 35 of its housing 24, and a second connecting piece 36 is arranged at the second axial end 22 of the infusion filter 14 or of the main part 35. Both connecting pieces 34, 36 extend in an axial / longitudinal direction along a longitudinal axis 21 of the infusion filter 14, in particular coaxially to the cylindrical main part 35 and to an approximately cylindrical filter membrane 26. Referring back to Figure 1, the first tube 12 and the second tube 16 can be coupled to the infusion filter 14 in a suitable manner.

[0116] The infusion filter can:

[0117] - be integrated into the tubing of the infusion line (in this case, the tubing is glued directly into the end caps), or

[0118] - be equipped with separate hoses (in this case the hoses are glued into the end caps from one side and fitted with a Luer-Lock on the other side), or

[0119] - are equipped with end caps that are directly Luer-Locks.

[0120] The filter membrane 26 is designed as a capillary membrane and therefore comprises a multitude of hollow fibers arranged side by side, which together form a hollow fiber bundle 30, approximately cylindrical in shape. The hollow fiber bundle 30 extends along a longitudinal axis 21 within the interior of the housing 24. The filter membrane 26, or rather its hollow fibers, are made of a hydrophilic thermoplastic, for example, polysulfone or polyethersulfone, and have pores that allow the flow of infusion fluid (infusion solution) through them, while filtering out particles, bacteria, endotoxins, and fungi from the infusion fluid. The filter membrane 26 can, in particular, be designed as a microporous membrane with a pore size of 0.1 pm to 20 pm.

[0121] In a region of the second axial end 22 of the infusion filter 14 (immediately upstream of the second connecting piece 36), an embedding formed from an adhesive 37 is provided. The embedding embeds the hollow fibers of the hollow fiber bundle 30 in the main part 35 of the housing 24, that is, it secures (seals / bonds) the hollow fibers to each other and to the main part 35. The hollow fibers are open at the second axial end 22, and spaces between the hollow fibers are sealed by the adhesive 37. In other words, an infusion fluid can only leave the infusion filter 14 through the interior of the hollow fibers 30 via the holes of the hollow fibers of the hollow fiber bundle 30 at the second axial end 22, as shown in Figure 2b. In a region of / near the first axial end 20 of the infusion filter 14, the hollow fibers 30 are closed in all embodiments.In the first embodiment according to Figures 2a and 2b, this is achieved by having two hollow fibers formed as a single unit and having a 180° bend at that point. When the infusion fluid thus enters the interior of the infusion filter 14 via the first axial end 20 or the first connecting piece 34, it initially flows in the spaces between the hollow fibers. However, due to the seal created by the adhesive 37 of the embedding at the second axial end 22, the infusion fluid cannot leave the infusion filter 14 through the spaces between the hollow fibers. Therefore, the infusion fluid must flow completely through the walls of the hollow fibers within the infusion filter 14 in order to exit the infusion filter 14 again at the second axial end 22.

[0122] As the infusion fluid flows through the walls of the hollow fibers, it is filtered so that particles / bacteria / endotoxins / fungi preferentially do not leave the infusion filter 14 at the second axial end 22. Thus, only filtered infusion fluid flows out of the second axial end 22.

[0123] According to the disclosure, disc-shaped, and in particular internally open, i.e., annular, venting membrane rings 34a, 36a are arranged between the end-face contact surfaces 35c, 35d of the main part 35 and corresponding contact surfaces 36c of the connecting pieces 34, 36, which are designed as end caps. The unfiltered infusion fluid can be vented to the environment via these venting membrane rings. The unfiltered infusion fluid is located on the outer circumference of the hollow fiber bundle 30. Due to the venting membrane rings 34a, 36a being designed to extend completely around the longitudinal axis 21, the rotational position of the infusion filter 14 (viewed about the longitudinal axis 21) is irrelevant. The arrangement of a venting membrane ring 34a, 36a on each side ensures that venting is also independent of rotational positions of the infusion filter 14 about the two remaining spatial axes.

[0124] Figure 2b shows that the venting of the outlet-side venting membrane ring 36a to the environment occurs via outlet-side through-holes 36b evenly distributed around the circumference of the outlet-side connecting piece 36. More precisely, the through-holes 36b are arranged evenly around the circumference of the outlet-side contact surface 36c of the outlet-side connecting piece 36. The same applies to the inlet side.

[0125] Figure 3a shows a further embodiment of the infusion filter 114 according to the disclosure in a side view, while Figure 3b shows the infusion filter 114 from Figure 3a in a longitudinal section. A significant difference from the first embodiment according to Figures 2a and 2b is that the main part 35 of the housing 24 has a shoulder or radial step, so that a respective centering ring 34d, 36d of each connecting piece 34, 36 is flush with the outer circumference of the main part 35. This forms a housing 24 that cannot snag or catch on anything. Another significant difference from the first embodiment according to Figures 2a and 2b is that the filter membrane 126 is formed on the inlet side by sealed end sections of the individual hollow fibers of the hollow fiber bundle 30, which are welded together.

[0126] Figure 3c shows the inlet-side connecting piece 34, designed as an end cap and forming the inlet area 20 of the infusion filter 114 from Figure 3a, in a further perspective longitudinal section. It can be seen that on the inner circumference of the inlet-side contact surface 35c of the main part 35, the unfiltered infusion fluid (at the outer circumference of the weld 126a) comes into full contact with the outlet-side venting membrane ring 36a.

[0127] Figure 3d shows the outlet-side connecting piece 36, designed as an end cap, which forms the inlet area 22 of the infusion filter 114 from Figure 3a. It can be seen that the main part 35 has through-holes 35b only on the outlet side, through which unfiltered infusion fluid comes into contact with the outlet-side venting membrane ring 36a, and which correspond to the outlet-side through-holes 36b of the outlet-side connecting piece 36.

[0128] Figure 4 shows an embodiment of a filter membrane, e.g., the filter membrane 126 of the embodiment shown in Figures 3a to 3d, wherein the filter membrane 126 is designed as a hollow fiber bundle 30. In the intermediate state of its manufacture shown, the filter membrane 126 has welds 126a on both sides, of which only one inlet-side weld 126a can remain in the final state (e.g., according to the embodiment shown in Figures 3a to 3d), since the individual hollow fibers must be open on the outlet side.

[0129] Figure 5 shows the filter membrane 26 of the embodiment from Figures 2a to 2b, which is designed as a hollow fiber bundle 30, in an intermediate stage of its manufacture. The filter membrane 26 also has welds 126a on both sides, which in the final state are both arranged on the outlet side and are both cut off there, since the individual hollow fibers of the hollow fiber bundle 30 must be open on the outlet side.

[0130] The 180° bend of the hollow fiber bundle 30 (on the right in Figure 5) represents the inlet end section of the hollow fiber bundle 30, where the individual hollow fibers must be closed.

[0131] Figure 6 shows another embodiment of a filter membrane 226, which is designed as a hollow fiber bundle 30, in an intermediate stage of its manufacture. The hollow fiber bundle 30 is surrounded by yarn 226a and thus mechanically supported.

[0132] Figure 7 shows another embodiment of a filter membrane 326, which is designed as a hollow fiber bundle 30, in an intermediate stage of its manufacture. The hollow fibers are twisted to achieve a better distribution of the unfiltered infusion fluid between the hollow fibers.

[0133] The hollow fibers can also be undulated to achieve a better distribution of the unfiltered infusion fluid between the hollow fibers.

[0134] Figure 8 shows another embodiment of a filter membrane 426 in an intermediate stage of its manufacture. The hollow fibers are spread out flat and interwoven with transverse hollow fibers or yarn to mechanically support the hollow fiber bundle 30 to be subsequently rolled up.

[0135] The hollow fiber bundle can also be a loop made from a continuous fiber. The loop can then be embedded from one side but not the other. The open ends can, for example, either be closed before embedding or embedded directly.

[0136] Figure 9a shows a further embodiment of an infusion filter 514 according to the disclosure in an exploded view. Its filter membrane 526 is cylindrical or bushing-shaped and is mechanically supported by an inner support cage 527. The infusion fluid flows radially through the filter membrane 526 and the support cage 527 from the outside to the inside. The support cage 527 has longitudinal ribs that are aligned parallel to the longitudinal axis 21.

[0137] The housing of the infusion filter 514 with the functional connections of the two sections of the main part 35 with those of the two connecting pieces 34, 36 and in particular with the venting membrane rings 34a, 36a according to the disclosure correspond to those of the second embodiment from figures 3a to 3d.

[0138] Figure 9b shows an alternative support cage 528 for the infusion filter 514 from Figure 9a. Compared to the previous support cage 527, the support cage 528 has a denser support structure for more uniform support of the circular cylindrical or bushing-like filter membrane 526.

[0139] In both embodiments, the isolation of the incoming infusion fluid from the already filtered infusion fluid is achieved by a circular cover of the support cage 527, 528.

[0140] Figure 10 shows another embodiment of a filter membrane 626. Compared to the previous embodiment, it has an increased filter area, since the filter membrane 626 is formed from two circular cylindrical sections 626a, 626b, which extend along the longitudinal axis 21 and are concentric with each other. A space for the filtered infusion fluid is formed between the two sections 626a, 626b. The space has (in Figure 19, left) an annular outlet for the filtered infusion fluid.

[0141] The incoming infusion fluid is separated from the filtered infusion fluid by an annular lid 626c. In its center is an inlet opening for unfiltered infusion fluid, which is then filtered by the inner cylindrical section 626a.

[0142] In a variant of the embodiment shown in Figure 10, the inner and outer circular cylindrical sections 626a, 626b are separated by a (not shown) concentric cylinder separator.

[0143] This cylindrical separator divides the space visible in Figure 10 between the two circular cylindrical sections 626a and 626b into an outer space for the infusion fluid filtered by the outer circular cylindrical section 626b and an inner space for the infusion fluid to be filtered by the inner circular cylindrical section 626a. In this way, filtration of both cylindrical sections 626a and 626b takes place from their outer surface to their inner surface.

[0144] Figure 11 shows another embodiment of a filter membrane 726. This filter membrane 726 is also formed from two adjacent sections or walls 726a, 726b, which are spaced at a constant distance from each other, so that a shallow space for filtered infusion fluid is formed between them. The two walls 726a, 726b and the shallow space are arranged (wound) in a spiral around the longitudinal axis 21. The outlet for the filtered infusion fluid (left in Figure 11) has the shape of a spiral.

[0145] The isolation of the incoming infusion fluid from the filtered infusion fluid is achieved by a spiral-shaped cover element 726c.

[0146] Figure 12 shows a further embodiment of a substantially cylindrical filter membrane 826 in a simplified schematic representation. The filter membrane 826 is designed as a bellows with edges 826a, 826b running around the longitudinal axis 21. Radially inner edges 826a and radially outer edges 826b alternate, resulting in a zigzag shape (in the longitudinal section shown).

[0147] The bellows is fluid-tightly connected to an inlet-side support cup 828 via a welded connection 827 and to an outlet-side support ring 829 via another welded connection 827.

[0148] The separation of the incoming infusion fluid from the filtered infusion fluid is achieved by a base of the support pot 828.

[0149] This filter membrane 826 can also be attached to a simple cylindrical part (e.g.

[0150] The support cage 527 from Fig. 9a) is sealed.

[0151] Figure 13 shows a further embodiment of a substantially cylindrical filter membrane 926 in a sectional view. The filter membrane 926 is (also) designed as a bellows with edges 926a, 926b running around the longitudinal axis 21. Radially inner edges 926a and radially outer edges 926b alternate, resulting in the zigzag shape shown in the longitudinal section.

[0152] The bellows is held by an inner support cage 927 which, viewed along the longitudinal axis 21, alternately has radially inner support sections for the radially inner edges 926a and radially outer support sections for the radially outer edges 926b of the bellows.

[0153] The isolation of the incoming infusion fluid from the filtered infusion fluid is achieved by a circular cover 927a of the support cage 927.

[0154] Figure 14 shows a further embodiment of an infusion filter 1014 according to the disclosure in a schematic sectional view. Its BB2580P-WQ-0004

[0155] 27 / 39

[0156] In longitudinal section, the filter membrane 1026 is meandering or formed as a sequence of sections arranged at angles to one another. The filter membrane 1026 is attached to the inner side of the main part 35 of the housing by means of an inlet weld 1026a and an outlet weld 1026b. Since the two welds 1026a and 1026b are located on opposite sides of the inner side of the main part 35, the outlet weld 1026b can axially define an inlet space (upper in Figure 14) and the inlet weld 1026a a discharge space (lower in Figure 14).

[0157] Figure 15 shows a further embodiment of an infusion filter 1114 according to the disclosure in an exploded view with a cylindrical filter membrane 1126. The infusion filter 1114 largely corresponds to the embodiment shown in Figure 9a. The essential difference is that no support cage is provided.

[0158] The isolation of the incoming infusion fluid from the filtered infusion fluid is achieved by a circular end face of the filter membrane 1026 or by sealing the filter membrane 1026 on this side.

[0159] Figure 16 shows a further embodiment of an infusion filter 1214 according to the disclosure in an exploded view. The housing and its functional connection with the two venting membrane rings 34a, 36a largely correspond to the embodiment shown in Figure 9a. The essential difference is that a filter membrane 1226, which is cross-shaped in cross-section, is provided. A support structure is also provided, which has several webs 1227 extending parallel to the longitudinal axis 21.

[0160] The separation of the incoming infusion fluid from the filtered infusion fluid is achieved by a cross-shaped cover of the support structure.

[0161] Figure 17a shows a section of another embodiment of a filter membrane 1326 in a view (in the broadest sense in the direction of flow), BB2580P-WQ-0004

[0162] 28 / 39

[0163] while Figure 17b shows a section of the filter membrane 1326 from Figure 17a in a further view (in the broadest sense against the flow direction).

[0164] The filter membrane 1326 has a multitude of lamellae, which are held and stabilized on the inlet side by an inlet-side disc-shaped support element 1326a and on the outlet side by an outlet-side ring-shaped support element 1326b. Due to the multitude of lamellae, their cross-section can be described as star-shaped.

[0165] The isolation of the incoming infusion fluid from the filtered infusion fluid is achieved by the disc-shaped support part 1326a on the inlet side, which forms a lid.

[0166] Figure 18 shows another embodiment of a filter membrane 1426 in cross-section. The filter membrane 1426 has eight lamellae and an internal support structure with four webs 1427 extending along the longitudinal axis 21.

[0167] Figure 19 shows another embodiment of a filter membrane 1526 in cross-section. The filter membrane 1526 has six lamellae and an internal support structure with two webs 1527 extending along the longitudinal axis 21.

[0168] Figure 20 shows another embodiment of a filter membrane 1626 in a longitudinal section. The filter membrane 1626 has several pairs of inlet-side sections 1626a and outlet-side sections 1626b, which are frustoconical and concentric to the longitudinal axis 21. Each pair of sections 1626a, 1626b forms an internal, also frustoconical, flat space for the filtered infusion fluid, which is then collected in a central longitudinal tube extending concentrically to the longitudinal axis 21.

[0169] The incoming infusion fluid is isolated from the filtered infusion fluid by an inlet-side cover or plug of the longitudinal tube (left in Figure 20). BB2580P-WQ-0004

[0170] 29 / 39

[0171] Figure 21a shows another embodiment of a filter membrane 1726 in a view (broadly speaking, in the direction of flow). Figure 21b shows the filter membrane 1726 from Figure 21a in a further view (broadly speaking, against the direction of flow). The filter membrane 1726 is a hollow body extending along the longitudinal axis and composed of a cuboid central section 1726a and three (or six) cuboid longitudinal ribs 1726b. The central section 1726a and the longitudinal ribs 1726b together define an interior space (not visible) for the filtered infusion fluid. The central section 1726a has a central outlet for the filtered infusion fluid.

[0172] The isolation of the incoming infusion fluid from the filtered infusion fluid is achieved (with reference to Figure 21a) by a respective inlet-side rectangular cover of the three longitudinal ribs 1726b in combination with a circular cover, which is transparent in Figure 21b and which has only the outlet for the filtered infusion fluid.

[0173] Figure 22 shows the main part 35 of the housing of an infusion filter according to the disclosure in an intermediate state of its manufacture. In this state, a first embodiment of a still complete embedding pot 38 is integrally formed. This is open towards the interior of the main part 35 and closed at the end section facing away from the main part 35 by a bottom. This results in a circular cylindrical interior 38b of the embedding pot.

[0174] Figure 23 shows the main part 35 of the housing of an infusion filter according to the disclosure in an intermediate state of its manufacture. In this state, a second embodiment of a still complete embedding pot 138 is integrally formed. This is open towards the interior of the main part 35 and closed at the end section facing away from the main part 35. By means of a pin 138a, which extends from the bottom towards the main part 35, the interior 138b of the embedding pot 138 has an annular cross-section.

[0175] Figure 24a shows the main part 35 of the housing of an infusion filter according to the disclosure in an intermediate state of its manufacture. In this state, a BB2580P-WQ-0004

[0176] 30 / 39

[0177] A third embodiment of a still complete embedding pot 238 is integrally formed. More precisely, the embedding pot 238 has two pot parts 238a, each with a circular arc or kidney-shaped cross-section.

[0178] Figure 24b shows the main part 35 with the embedding pot 238 from Figure 24a in a sectional side view. It can be seen that, viewed in the direction of flow of the infusion fluid (from left to right in Figure 24b), the embedding pot 238 initially has an undivided, i.e., approximately circular-cylindrical, area.

[0179] Furthermore, it can be seen that the two pot parts 238a are still joined together in a central area, and that sections of the two pot parts 238a (removed from the main part 35) are attached to it, which are formed separately from each other and with a distance between them.

[0180] The three embodiments of the embedding pots 28; 138; 238 can be used to carry out the method shown in Figure 25 for manufacturing an infusion filter. It comprises the following steps:

[0181] - Manufacturing the main part 35 (S1) with an embedding pot 38; 138; 238 formed integrally therewith according to one of the embodiments from Figures 22 to 24b;

[0182] - Embedding an end section of a hollow fiber bundle 30 by means of adhesive 37 in the embedding pot 38; 138; 238 (S2). In this process, the end sections of the hollow fibers of the hollow fiber bundle 30 are surrounded by the adhesive 37, and the adhesive 37 seals the end section of the hollow fiber bundle 30, in particular against the shell of the embedding pot 38; 138; 238.

[0183] - Forming end-face hollow fiber openings (S3) sealed by adhesive 37 by separating an outermost section of the embedding pot 38; 138; 238, including the portion of the end section of the hollow fiber bundle arranged therein and the portion of adhesive 37 surrounding this portion of the end section. The separation results in a (section) plane S perpendicular to the longitudinal axis 21, as shown in Figure 3b.

[0184] - Assembly (S4, S5) of the two venting membrane rings 34a, 36a by attaching the two connecting pieces 34, 36 to the main part 35.

[0185] Reference list Infusion unit

[0186] Infusion container

[0187] Infusion set / infusion system, infusion access

[0188] Infusion container connection

[0189] first hose

[0190] ; ...; 1214 Infusion filters

[0191] second hose

[0192] Infusion access port

[0193] (first axial end / ) Entrance area longitudinal axis

[0194] (second axial end / ) starting area

[0195] Housing

[0196] ; ...; 1726 Filter membrane

[0197] Hollow fiber bundles

[0198] (first) inlet-side connecting piece a inlet-side venting membrane ring b inlet-side through-hole (of 34) c inlet-side contact surface (of 34)

[0199] d centering ring (of 34)

[0200] Main part

[0201] b exit-side passage recess (of 35) c entrance-side mounting area (of 35)

[0202] d exit-side installation area (of 35)

[0203] (second) outlet-side connecting piece a outlet-side venting membrane ring b outlet-side through-recess (of 36) c outlet-side contact surface (of 36)

[0204] d centering ring (of 36)

[0205] adhesive

[0206] ; 138; 238 Embedding pot

[0207] b; 138b; 238b Interior 126a Welding

[0208] 138a Pin

[0209] 226a Yarn

[0210] 238a Pot part (of 238)

[0211] 527; 528 Support cage

[0212] Sections 626a and 626b

[0213] 626c circular lid 726a, 726b wall

[0214] 726c spiral cover element 827 welded joint

[0215] 828, 829 carrying ring

[0216] 826a; 926a radial inner margin

[0217] 826b; 926b radial outer edge

[0218] 927 Support structure

[0219] 927a Lid

[0220] 1026a Inlet weld 1026b Outlet weld 1227; 1427; 1527 Bridge

[0221] 1326a inlet-side support element 1326b outlet-side support element 1626a inlet-side section 1626b outlet-side section 1726a central section

[0222] 1726b Longitudinal rib

[0223] S (section) plane

[0224] S1 step

[0225] S2 step

[0226] S3 step

[0227] S4 step

[0228] S5 step

Claims

33 / 39 Claims 1. Infusion filter (14; 114; 514; 1014; 1114; 1214), which is designed to filter out particles and / or bacteria and / or endotoxins and / or fungi from an infusion fluid and to separate air contained in the infusion fluid, with a housing (24) extending from an inlet area (20) to an outlet area (22) along a longitudinal axis (21), wherein a filter membrane (26; 126; 226; 326; 426; 526; 626; 726; 826; 926; 1026; 1126; 1226; 1326; 1426; 1526; 1626;1726) is arranged, which is designed to filter out particles and / or bacteria and / or endotoxins and / or fungi from the infusion fluid, wherein an inlet-side venting membrane ring (34a) is arranged in the inlet area (20), and wherein an outlet-side venting membrane ring (36a) is arranged in the outlet area (22), wherein both venting membrane rings (34a, 36a) are hydrophobic and connect an interior of the housing (24) with the environment, thereby enabling the separation, in particular independent of position, of air contained in the infusion fluid, wherein both venting membrane rings (34a, 36a) are disc-shaped, in particular annular, and surround the longitudinal axis (21).

2. Infusion filter (14; 114; 514; 1014; 1114; 1214) according to claim 1, wherein the housing (24) is at least three-part, preferably three-part or four-part, and has an inlet-side connector (34) forming the inlet region (20) and an outlet-side connector (36) forming the outlet region (22), wherein both connectors (34, 36) are spaced apart from each other along the longitudinal axis (21) and are attached to a cylindrical main part (35) of the housing (24), wherein the inlet-side venting membrane ring (34a) is arranged between the inlet-side connector (34) and the main part (35), and wherein the outlet-side venting membrane ring (36a) is arranged between the outlet-side connector (36) and the main part (35).

3. Infusion filter (14; 114; 514; 1014; 1114; 1214) according to claim 2, wherein the two connecting pieces (34, 36) each form end caps which are dome-shaped or cup-shaped, and which each have an axial contact surface (34c, 36c) circumferentially around the longitudinal axis (21), on the outer circumference of which a respective centering rim for the main part (35) and for the respective venting membrane ring (34a, 36a) is arranged, wherein the main part (35) has an inlet-side end face and an outlet-side end face with a respective contact surface circumferentially around the longitudinal axis (21) around a continuous, in particular disc-like, axial contact surface (35c, 35d), wherein each venting membrane ring (34a, 36a) is arranged between the contact surface (34c, 36c) of the respective connecting piece (34, 36) and one of the contact surfaces (35c, 35d) of the main part (35), and wherein in at least one contact surface (34c, 36c) of the connecting pieces (34, 36), preferably in both contact surfaces (34c, 36c) of the connecting pieces (34, 36), uniformly distributed passage recesses (34b, 36b) are formed, which connect the respective venting membrane ring (34a, 36a) to the environment.

4. Infusion filter (14; 114; 514; 1014; 1114; 1214) according to claim 2 or 3, wherein the main part (35) and the two connecting pieces (34, 36) and the two venting membrane rings (34a, 36a) are rotationally symmetrical to the longitudinal axis (21), and wherein preferably the contact surfaces (34c, 35c, 35d, 36c) are circular annular disks and the centering edges are centering rings (34d, 36d) and the passage recesses (34b, 36b) are arc-shaped.

5. Infusion filter (14; 114) according to one of claims 1 to 4, wherein the filter membrane (26; 126; 226; 326; 426) is designed as a capillary membrane with a hollow fiber bundle (30).

6. Infusion filter (14; 114) according to claim 5, wherein the hollow fibers of the capillary membrane are embedded and sealed in the outlet region (22) of the housing (24) by means of an adhesive (37).

7. Infusion filter (514; 1114) according to any one of claims 1 to 4, wherein the filter membrane (526; 1126) is cylindrical in shape and through which the infusion fluid flows radially from the outside to the inside.

8. Infusion filter (514; 1126) according to claim 7, wherein the filter membrane (526) is attached to an inner support cage (527; 528).

9. Infusion filter according to any one of claims 1 to 4, wherein the filter membrane (626) is formed from two circular cylindrical sections (626a, 626b) which are concentric to each other, wherein a space for filtered infusion fluid is formed between the two circular cylindrical sections (626a, 626b).

10. Infusion filter according to one of claims 1 to 4, wherein the filter membrane (726) is formed from two adjacent walls (726a, 726b) between which a flat space for filtered infusion fluid is formed, wherein the two walls (726a, 726b) and the space formed between them are arranged spirally around the longitudinal axis (21).

11. Infusion filter according to one of claims 1 to 4, wherein the filter membrane (826; 926) is essentially cylindrical in shape and is radially permeated by the infusion fluid from the outside to the inside, wherein the filter membrane (826; 926) is designed as a bellows with edges (826a, 826b; 926a, 926b) circumferential around the longitudinal axis (21), wherein radially inner edges (826a; 926a) and radially outer edges (826b; 926b) are provided alternately.

12. Infusion filter according to claim 11, wherein the filter membrane (826) is fluid-tightly connected to an inlet-side support pot (828) via a welded connection (827) and to an outlet-side support ring (829) via a welded connection (827).

13. Infusion filter according to claim 11, wherein the filter membrane (926) is held by a support structure (927) viewed along the longitudinal axis (21) BB2580P-WQ-0004 36 / 39 It has alternating radially inner support sections and radially outer support sections.

14. Infusion filter according to any one of claims 1 to 4, wherein the filter membrane (1026) is designed in longitudinal section as meandering or as a sequence of sections arranged at an angle to each other, and wherein the filter membrane (1026) is attached to an inside of the main part (35) of the housing (24) by means of an inlet weld (1026a) and an outlet weld (1026b).

15. Infusion filter (1214) according to one of claims 1 to 4, wherein the filter membrane (1226; 1326; 1426; 1526) is cross-shaped or star-shaped in cross-section.

16. Infusion filter according to claim 15 with a support structure comprising several webs (1227; 1427; 1527) which extend parallel to the longitudinal axis (21).

17. Infusion filter according to any one of claims 1 to 4, wherein the filter membrane (1626) has several pairs of inlet-side sections (1626a) and outlet-side sections (1626b), wherein the sections (1626a, 1626b) are frustoconical and concentric to the longitudinal axis (21), and wherein a frustoconical space for filtered infusion fluid is formed between the two sections (1626a, 1626b) of each pair.

18. Infusion filter according to any one of claims 1 to 4, wherein the filter membrane (1726) is a hollow body extending along the longitudinal axis (21) and is composed of a central section (1726a) and several longitudinal ribs (1726b), wherein the central section (1726a) and the longitudinal ribs (1726b) define a common interior space, wherein the central section (1726a) has an outlet for the filtered infusion fluid.

19. Infusion set (6) with an infusion filter (14; 114; 514; 1014; 1114; 1214) according to one of the preceding claims, and with a first tube (12), 37 / 39 which is connected to the infusion filter (14) at the inlet area (20), and with a second tube (16) which is connected to the infusion filter (14; 114; 514; 1014; 1114; 1214) at the outlet area (22).

20. Infusion device (2) comprising an infusion set (6) according to claim 19 and an infusion container (4) and an infusion access (8), wherein the infusion set (6) connects the infusion container (4) to the infusion access (8).

21. Method for manufacturing an infusion filter (14; 114; 514) preferably according to one of claims 1 to 18, comprising the steps - Manufacturing a main part (35) of a housing (24) with an embedding pot (38; 138; 238) (S1); - Embedding an end section of a hollow fiber bundle (30) by means of adhesive (37) in the embedding pot (38; 138; 238) (S2), wherein the end sections of the hollow fibers of the hollow fiber bundle (30) are surrounded by the adhesive (37), and wherein the end section of the hollow fiber bundle (30) is sealed against the embedding pot (38; 138; 238) by the adhesive; - Forming end-face hollow fiber openings (S3) which are sealed by adhesive (37) by separating an outer part of the embedding pot (38; 138; 238) including the part of the end section of the hollow fiber bundle (30) arranged therein and including the adhesive (37) which surrounds the part of the end section of the hollow fiber bundle (30).

22. Method for manufacturing an infusion filter (14; 114; 514) according to claim 21, wherein, according to the aforementioned steps (S1, S2, S3), an inlet-side venting membrane ring (34a) (S4) and an inlet-side connector (34) are mounted on the main part (35), wherein the mounting of the inlet-side venting membrane ring (34a) is preferably carried out by attaching the inlet-side connector (34) to the main part (35), and wherein, according to the aforementioned steps (S1, S2, S3), an outlet-side venting membrane ring (36a) (S5) and an outlet-side connector (34) are mounted on the main part (35), wherein the mounting of the 38 / 39 The outlet-side venting membrane ring (34a) is preferably attached by fastening the outlet-side connecting piece (36) to the main part (35).

Images