DISPOSABLE DEVICE FOR FILTRATION OF A LARGE MEDIUM VOLUME

Description

[0001] The invention relates to a disposable device for filtering a large volume of medium.

[0002] In general, disposable devices are becoming increasingly popular in the pharmaceutical production of high-quality active ingredients due to the high degree of flexibility they offer, as well as savings in time, investment, and operating costs such as cleaning, validation, and testing. Disposable devices are increasingly desired for larger scale (high-volume processes), although the costs of such systems should not increase unrealistically.

[0003] WO 2017 / 032560 A1 discloses a fully pre-sterilizable, ready-to-connect, and integrity-testable disposable filtration device designed for large-volume filtration processes. This disposable filtration device comprises a plurality of disposable filter capsules of a standard size arranged in a predetermined grid and connected to each other by lines. The filter capsules are supported by a rigid holder.

[0004] DE 20 2017 103 082 U1 describes a preconfigured disposable filtration device with a disposable hollow fiber filter capsule and a sterilizable air filter that is connected to a vent port of the disposable filter capsule via a vent line.

[0005] WO 2008 / 039278 A1 discloses a water filtration system for producing drinking water, which removes microorganisms and organic contaminants and sterilizes containers and water pipes. In one embodiment of this system, the water first flows into a 5-micron filter 62 and then into a 1-micron filter.

[0006] The object of the invention is to provide a cost-effective and effective disposable filtration device suitable for large-scale virus filtration.

[0007] This object is achieved by a device having the features of claim 1 and a method having the features of claim 14. Advantageous and expedient embodiments of the device according to the invention are specified in the subclaims.

[0008] The disposable device according to the invention for filtering a large volume of medium comprises a plurality of disposable filter units, at least some of which, preferably all of which, are connected to one another by rigid lines formed by pressure-resistant pipes with a defined diameter. According to the invention, the filter units comprise several prefilters and several main filters designed as hollow fiber capsules for virus filtration. A common outlet line is provided for several prefilters. At least one check valve is provided in the outlet line between the prefilters and the main filters to enable all main filters to be connected to form a group separate from the prefilters.A common vent line is provided for the main filters, which leads to a sterile air filter on the unfiltered side, so that test gas can be supplied to all main filters via the sterile air filter through the vent line to carry out an integrity test of all main filters.

[0009] In general, a prefilter always has a membrane with larger pores than a downstream main filter. A typical classification of porous membranes can be made based on their pore size. Based on pore size, a distinction is generally made between microfiltration membranes (average pore size: 0.1 to 10 µm), ultrafiltration membranes (average pore size: 0.01 to less than 0.1 µm), nanofiltration membranes (average pore size: 0.001 to less than 0.01 µm), and reverse osmosis membranes (average pore size: 0.0001 to less than 0.001 µm) (see Shang-Tian Yang, Bioprocessing for Value-Added Products from Renewable Resources, 2007). In the field of microfiltration, the mean pore size is determined, for example, by means of capillary flow porometry (see Shrestha, Aabhash, "Characterization of porous membranes via porometry" (2012), Mechanical Engineering Graduate Theses & Dissertations, Paper 38).A similar measurement method is used to characterize the pore size distribution in ultra- and nanofiltration membranes, with the difference that not gas flow rates but flow rates of the displacing liquid are recorded as a function of the differential pressure increase (see R. Dávila, Characterization of Ultra and Nanofiltration commercial Filters by Liquid-Liquid Displacement Porosimetry, 2013).

[0010] While the main filters of the disposable filtration device according to the invention are designed as hollow fiber capsules for virus filtration with a typical average pore size of 0.01 to 0.1 µm, preferably 0.02 µm, pleated filter elements, flat filters, hollow fiber capsules, depth filters, etc., can be considered as prefilters. The prefilters can also be sterile filters with a pore size in the range of 0.1 to 8 µm, preferably 0.2 µm.

[0011] The invention is based on the finding that a combination of several disposable filter units that are rigidly piped together can handle filtration on a large scale.

[0012] The rigid lines, in particular a common inlet line and / or a common outlet line for several pre-filters and / or a common inlet line and / or a common outlet line for several main filters of the disposable filtration device, are preferably formed by pressure-stable tubes with a defined diameter. This means that the diameter is not arbitrarily selected and does not vary during operation due to material expansion or similar. This results in a uniform pressure distribution and a uniform flow velocity of the filtration medium when flowing towards the filter units. This would not be the case if the filter units were connected with (thin) hoses, since typically different hose lengths and different hose diameters would be present, the consistency of which cannot be guaranteed during operation, especially at high and fluctuating pressure.Another advantage of using rigid distribution pipes is that a shared flow volume calms the flow and reduces pressure surges. This reduction in pressure surges generally protects membranes with a wall thickness of less than 150 µm, which is particularly true for the hollow fiber filter elements used for virus filtration. The overall avoidance of pressure fluctuations results in higher phage retention compared to phage filtration processes with high pressure pulsations.

[0013] Particularly preferably, the connection of prefilters and main filters is formed within the disposable filtration device using rigid piping, particularly preferably with identical pipe inner diameters. This results in further advantages in addition to the aforementioned uniform flow conditions and reduced pressure fluctuations. Overall, a compact, stable structure with fewer connections and less dead volume can be achieved. The device is thus easier to handle overall.

[0014] In particular, the disposable filtration device according to the invention provides that a rigid line made of a pressure-stable pipeline with a defined diameter is present between the pre-filters and the main filters.

[0015] It is also particularly preferred to design an inlet line to the main filters as a rigid line made of a pressure-stable pipe with a defined diameter.

[0016] For the preferred application of virus filtration, a setup is provided in which the multiple pre-filters are connected in series as a group with a group of main filters.

[0017] With a view to a problem-free integration of the disposable filtration device according to the invention into a process chain, the device has both a common inlet connection and a common outlet connection for the filtration medium and can be integrated into an existing filtration line of a process arrangement by means of sterile connectors.

[0018] For most applications, it is sensible to combine the pre-filters and the main filters and to flow to them simultaneously as a group, ie the filter units and the rigid lines are arranged in such a way that all pre-filters and all main filters are flowed to in parallel.

[0019] According to a preferred embodiment, the prefilters are designed for dead-end filtration, and the main filters are designed for cross-flow filtration. However, both the prefilters and the main filters can be designed for dead-end filtration or cross-flow filtration.

[0020] According to a further development of the invention, the rigid lines between the filter units provided according to the invention can also be formed by common housings of the filter units. This means that no separate lines are provided between certain filter units, but rather the filter units are combined into a single structural unit.

[0021] At least one filter unit can be designed as a multiple capsule with at least two filter elements installed in a common housing. The filter elements in the multiple capsule can be of the same type or different. The use of such multiple capsules reduces the required connections within the disposable filtration device according to the invention and the space required within a production room for installing the device.

[0022] Within a multiple capsule, the filter elements can be arranged either so that they are subjected to parallel flow or so that they are subjected to sequential flow. The first arrangement is recommended for similar filter elements, all of which serve for prefiltration or main filtration. The second arrangement is recommended for different filter elements, where one type of filter element is intended for prefiltration and the other for main filtration within the same capsule.

[0023] In particular, a pre-filter and a main filter can be combined in a multiple capsule by the multiple capsule having at least one pleated filter element (pre-filter) and one hollow fiber filter element (main filter). As indicated above, two or more pleated filter elements can also be provided as a multiple pre-filter within a capsule, which is then connected to a hollow fiber capsule via a rigid connecting line. It is also possible for several hollow fiber elements to be arranged in a capsule, each of which serves as a pre-filter or each of which serves as a main filter, or at least one of which serves as a pre-filter and at least one of which serves as a main filter. As explained above, a sterile filter can also be incorporated into the multiple capsule as a pre-filter, so that, for example, for step-by-step filtration, the combination of a (pleated or hollow fiber) pre-filter, sterile filter, and main filter can be installed within one capsule.

[0024] In a further preferred embodiment, certain filter units, in particular a group of main filters and / or a group of pre-filters, are each designed as a module. This modular design allows for the easy insertion or replacement of an entire filter group. It is also possible to test a group of filters for integrity at once, either inside the device or externally (offline).

[0025] According to the invention, a common vent line is provided for the main filters, which leads to a sterile air filter. A test gas can be pumped in reverse via the sterile air filter to the filter units to subject them to a joint integrity test.

[0026] To protect the sterile air filter from clogging due to unwanted contact with liquid, a pressure-resistant sight glass can be integrated into the common vent line. The sight glass allows for visual verification of correct venting and can also be used to indicate the fill level in the filter unit(s). The established term "sight glass" generally refers to a transparent tube section and is not intended to be restrictive with regard to the material selection. In addition to real glass, a transparent plastic can also be used for the pressure-resistant design of the tube section. Another or complementary solution for visualizing liquid in the vent line is to install an indicator in the vent line that reacts to water, e.g., by a clearly visible color change.An additional protective filter can also be installed in front of the inlet of the sterile air filter to protect the sterile air filter and prevent the passage of water.

[0027] A vent valve provided in the vent line or on the sterile air filter can be released after filtration so that a portion of the remaining unfiltered material can still pass through the filter units due to the static pressure caused by its own weight and thus increase the amount of filtrate, whereby the open vent valve allows the flow of sterile air.

[0028] In order to enable a targeted integrity check for all main filters within the device, at least one check valve is provided between the pre-filters and the main filters in the common outlet line for several pre-filters.

[0029] Preferably, at least one filter unit of the disposable filtration device according to the invention, preferably all main filters, is oriented so that it receives flow from bottom to top. Such flow to the filter unit ensures uniform hydrostatic conditions, which in turn evens out the filtration and thus improves phage retention.

[0030] In a preferred design of the filter units, especially the main filter, a lower unfiltered material inlet, a lower filtrate outlet, an upper filtrate outlet, and an upper vent connection are provided. One of the two filtrate outlets can be used to discharge a purging or wetting medium or, as part of an integrity test, to supply a test gas.

[0031] Providing valves to block the lower unfiltered water inlets and to block the vent connections is advantageous for targeted testing of individual filter units or groups of filter units for integrity. Filter units not to be tested are isolated by appropriate valve positions. The test is performed, for example, via a filtrate outlet.

[0032] In order to ensure a clear arrangement of the valves and ease of use, it is advantageous to arrange the majority of the valves on the same side of the disposable filtration device.

[0033] A flow-reducing element can be provided at the outlet of a filter unit or group of filter units to create a differential pressure for a flushing process. Such a flushing process is useful as part of an integrity test to ensure sufficient wetting of the filter membranes.

[0034] A further development of the disposable filtration device according to the invention provides an additional connection on the filtrate side of the device, to which a sterile air filter can be connected. After filtration, gas can be pumped through this sterile air filter to remove any filtrate remaining in the device. Completely emptying the device is particularly important because the unused product solution otherwise remaining in the device can be of considerable value (in the order of €500 to €5,000 / l). During regular filtration operation, the additional connection with the sterile air filter is protected from contact with the filtration medium by a valve or the like.

[0035] Independent of the latter, the previously mentioned sterile air filter is usually provided on a common vent line (possibly with an additional (hose) line interposed) to pump in a sterile test gas for conducting an integrity test. The sterile air filter can also be protected by a valve on the vent line or on the sterile air filter itself.

[0036] According to a further preferred embodiment, the lines leading to, from, or between the filter units are designed to be sterilely separated. This allows for convenient segments to be detached from the disposable filtration device for proper disposal. These segments can then be carried individually and placed individually in an autoclave.

[0037] Further features and advantages of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: Figure 1 a perspective view of a disposable filtration device according to the invention; Figure 2 a side view of the device Figure 1 ; and Figure 3 a perspective view of part of a disposable filtration device according to the invention with an additional air filter.

[0038] In the Figures 1 and 2 A disposable filtration device 10 is shown, which comprises a plurality of filter units 12, here in the form of filter capsules. The filter units 12 are held in position by a rigid holder 14 (rack) in a predetermined arrangement (grid).

[0039] Of the filter units 12, at least one unit is a hollow fiber capsule for virus filtration (hereinafter referred to simply as the main filter 12b for the sake of simplicity). At least one filter unit 12 serves for prefiltration (hereinafter referred to simply as the prefilter 12a for the sake of simplicity). The prefilters 12a preferably contain pleated filter elements, although other designs are also possible. Optionally, sterile filters can also be provided for stepwise filtration.

[0040] Preferably, the ratio of the number of prefilters 12a to main filters 12b is 1:1. Other ratios, in particular 1:2, 2:1, 1:3, 3:1, may also be appropriate depending on the specific circumstances (size, arrangement of the filters, etc.). For optimal filtration conditions, the effective filter areas of the prefilters 12a and the main filters 12b can also be used, whereby the same preferred ratios apply.

[0041] The disposable filtration device 10 has a common inlet connection 16 (unfiltered side) and a common outlet connection 18 (filtered side) for all filter units 12, so that it can be integrated into a filtration train.

[0042] The filter units 12 are completely or at least largely interconnected within the device 10 by rigid, pressure-resistant pipes of a defined diameter. The rigid pipes ensure uniform flow behavior without pressure fluctuations during operation. The routing of the pipes is determined by the intended operation of the disposable filtration device 10 (parallel and / or series connection of all or certain filter units 12), with the pipes having the necessary branches to the individual filter units 12. Where necessary, the pipes are attached to the bracket 14.

[0043] In the Figures 1 and 2In the embodiment shown, prefilters 12a and main filters 12b of various sizes are arranged in the stable holder 14 (rack). In particular, the main filters 12b are each designed as a vertical filter capsule with an unfiltered material inlet 24 on the lower end of the filter capsule and two filtrate outlets 26, 28 that are internally connected to one another, one of which is located at the lower end and one at the upper end of the filter capsule. Only one filtrate outlet is required for filtration itself. The purpose of the additional, optional filtrate outlet will be explained later.

[0044] The medium to be filtered flows from the inlet connection 16 through a common prefilter inlet line 34, which is designed as a rigid distribution pipe with a defined diameter and branches to the prefilters 12a. The prefilter inlet line 34 distributes the medium in parallel to all prefilters 12a. After passing through the prefilters 12a, the prefiltered medium is collected in a common prefilter outlet line 36, which in turn is designed as a rigid collection pipe with a defined diameter and branches to the prefilters 12a.

[0045] From the pre-filter outlet line 36, the pre-filtered medium flows via another rigid connecting line 38 to a common main filter inlet line 40, which is designed as a rigid distribution pipe with a defined diameter and branches to the main filters 12b. The main filter inlet line 40 distributes the medium in parallel to all main filters 12b. After passing through the main filters 12b, the filtered medium flows out of the lower filtrate outlets 26 and is collected in a common main filter outlet line 42, which in turn is designed as a rigid collection pipe with a defined diameter and branches to the main filters 12b. The filtrate finally flows out of the device 10 through the outlet connection 18.

[0046] A common main filter outlet line (not shown here) can also be provided for the upper filtrate outlets 28, which is designed as a rigid collecting pipe with a defined diameter.

[0047] The main filters 12b with their unfiltered water inlets 24 and the pipes are aligned so that the main filters 12b are flowed through from bottom to top, which ensures uniform hydrostatic conditions.

[0048] Both the prefilters 12a and the main filters 12b are designed for dead-end filtration. However, it is also possible for the prefilters 12a to be designed for dead-end filtration and the main filters 12b for cross-flow filtration. The longer service life of cross-flow filters compared to dead-end filters is particularly important for virus filtration.

[0049] The filter units 12 can be designed as multiple capsules. This means that several similar or different filter elements are housed in one common housing or in several rigidly connected housings. The filter elements within the multiple capsule can be subjected to flow in parallel or sequentially, depending on their design. In particular, two or more hollow fiber capsules can be housed in one housing. In another embodiment, a multiple capsule with at least one pleated filter element and one hollow fiber filter element is provided. The multiple capsules can generally be configured as a main filter 12b or as a pre-filter 12a. A combination of pre-filter 12a and main filter 12b within a multiple capsule housing is also possible.

[0050] The main filters 12b have vent connections 30 on their upper end faces, which open into a common vent line 20. The vent line 20 is designed as a rigid manifold with a defined diameter and branches to the main filters 12b. The vent line 20 leads, if necessary via another (hose) line, to a (in the Figures 1 and 2 Sterile air filter 22 (not shown).

[0051] The shared vent line 20 can contain a pressure-resistant sight glass upstream of the sterile air filter 22 in the direction of flow. The sight glass makes the medium rising toward the sterile air filter 22 visible to the user. This enables visual inspection of correct venting, allowing the user to take appropriate measures in a timely manner before the sterile air filter 22 comes into contact with liquid and becomes blocked. This can occur especially when liquid forms a film on a fleece supporting the membrane of the sterile air filter 22. The sight glass can also be used to monitor the fill level in the filter unit(s) 12.

[0052] For the same purposes, an indicator that reacts to water can be arranged in the vent line 20, alternatively or in addition to the sight glass. Such water contact indicators are available as adhesive tapes that turn red upon contact with water, or based on blue gel (silica gel), which turns pale pink. A further protective measure is a protective filter arranged in front of the sterile air filter 22, which is designed as a flat filter without supporting fleece or the like. The air filter membrane of the protective filter can be made of polyvinylidene fluoride (PVDF), polyethylene (PE), hydrophobic polyethersulfone (PESU), or polytetrafluoroethylene (PTFE). Since the protective filter has no supporting fleece, the risk of blockage is minimized.

[0053] The sterile air filter 22 can also be used as a test gas inlet during an integrity test, as will be described later.

[0054] All or certain filter units 12, in particular the main filters 12b and the pre-filters 12a, each form a module, so that an integrity test for an entire module can be carried out within the disposable filtration device 10, but also outside the disposable filtration device 10 (offline).

[0055] Shut-off valves can be provided between the filter units 12 so that connections between specific filter units 12 can be selectively blocked. This enables targeted sterile venting or a targeted sterile integrity test of an individual filter unit 12 or a group of interconnected filter units 12, e.g., all prefilters 12a and all main filters 12b.

[0056] When performing an integrity test, individual filter units 12, one or more groups of filter units 12 or all filter units 12 installed in the device 10 can be tested together.

[0057] To save costs and time, it is preferable to test all main filters 12b in one test step. For this purpose, a sterile air filter 22 (see Figure 3 ) from the unfiltered side through the vent line 20. During this test, only one valve on the prefilter outlet line 36 of the device 10 must be closed.

[0058] For a separate test of individual main filters 12b via the unfiltered-side sterile air filter 22, valves (not shown) are provided for each vent port 30 and each unfiltered inlet 24 to selectively block and open the ports or inlets. The valves are switched depending on the main filter 12b being tested.

[0059] If all filter units, including the prefilters 12a, are to be tested, instead of introducing the test gas through the vent line 20, it is also possible to pump the test gas into the unfiltered air inlet port 16 of the device 10. For this purpose, a sterile air filter is connected to the inlet port 16, through which the test gas passes before entering the filter units 12 through the unfiltered air inlets 24.

[0060] It is also possible to test the filter units 12 jointly or individually by pumping the test gas through the upper filtrate outlets 28 into the disposable filtration device 10 via a sterile air filter. For this purpose, for a joint test, all upper filtrate outlets 28 are connected to the test gas, if necessary via a manifold connected to these outlets, or only to one of the upper filtrate outlets 28, while the remaining filtrate outlets 28 are closed with a valve (not shown). The lower filtrate outlets 26 must be closed with valves (not shown) depending on the type of test (joint or individual test).

[0061] The most important valves, preferably all of those required to operate the disposable filtration device 10, are located on the same side of the disposable filtration device 10, which provides improved overview and simplified operability.

[0062] Before conducting an integrity test, it may be advantageous to flush the filter units 12, in particular the main filters 12b, with a wetting medium at a differential pressure. This ensures sufficient wetting for the integrity test. In order to regulate only the inlet pressure, a flow-reducing element is provided at the outlet of the respective filter unit 12 or filter unit group, which allows only a low flow and thus creates a differential pressure. The respective flow-reducing element must be matched to the size and number of filter units 12 to be flushed. For example, different resistances are necessary for a device with three, six, or nine (main) filter units 12. Such a flow-reducing element is typically designed for a specific application area, for example, for a combination of four to six filter units 12 of a specific design.For a different number of such filter units 12 (e.g. two or seven), a correspondingly differently designed flow-reducing element must then be provided.

[0063] One option for variable adjustment is the use of hoses of different lengths at the outlet of the filter units 12 to be flushed. The resistance created by the hose (friction of the fluid against the inner surface of the hose) can be adjusted by changing the hose length. Another option for variable flow during a flushing process is to design the flow-reducing element as a (proportional) valve, e.g., in the form of a pinch or diaphragm valve.

[0064] In Figure 31 shows part of an embodiment of the disposable filtration device 10, in which, for the sake of clarity, only the main filter 12b is visible. However, the sterile air filter 22 on the unfiltered side is shown here, connected to the common vent line 20 via a hose line. After filtration, a vent valve provided in the vent line 20 or on the sterile air filter 22 can be released, allowing sterilized air to flow through the sterile air filter 22 to the filter units 12. This allows a portion of the remaining unfiltered air to pass through the filter elements of the filter units 12 due to its own weight and the static pressure, thus increasing the amount of filtrate. This is facilitated by the preferred vertical installation of the filter elements in the filter units 12.

[0065] In addition, the Figure 3In the embodiment shown, a further, filtrate-side sterile air filter 32 is provided at an additional connection on the filtrate side of the device 10, more precisely on the main filter outlet line 42. Sterile gas can be pumped through this filtrate-side sterile air filter 32 after filtration is complete in order to discharge the filtrate remaining in the device 10 through the outlet connection 18. During the preceding filtration, the unfiltrate-side sterile air filter 32 is blocked by a valve, thus preventing fluid contact between the medium (product solution) and the filtrate-side sterile air filter 32.

[0066] In principle, each of the rigid, pressure-resistant pipes of device 10 can be equipped with a sight glass. For example, fill levels and adequate venting can be visually monitored in the common prefilter inlet line 34 of the common main filter outlet line 42.

[0067] For all embodiments, the materials used in the disposable filtration device 10 (including any flexible hose lines, etc.) are sterilizable, in particular by gamma radiation, heat, gassing, or autoclavable. The disposable filtration device 10 can thus be sterilized and packaged in a pre-assembled, i.e., ready-to-connect, state, or packaged first and sterilized together with the packaging. After delivery to a customer, the entire disposable filtration device 10 can be installed into an existing filtration line using sterile connectors, i.e., it is immediately ready for use.

[0068] To enable proper disposal of the disposable filtration device 10, which includes a sterilization step in an autoclave, the filter units 12 are connected to one another in the device 10 in such a way that they can be easily separated from one another. Separation is preferably carried out sterilely using the Quickseal® (Aseptic Tube Sealing System) product to avoid contamination. For disposal, the detached segments are selected in size and weight so that they can be carried by one person and transferred into an autoclave. Each detached filtration segment has at least one valve that can be opened during autoclaving to prevent excess pressure in the filtration segment during sterilization. List of reference symbols

[0069] 10 Disposable filtration device 12 Filter units 12a Pre-filter 12b Main filter 14 Bracket 16 Disposable filtration device inlet connection 18 Disposable filtration device outlet connection 20 Vent line 22 Unfiltered-side sterile air filter 24 Unfiltered-side inlet of a filter unit 26 Lower filtrate outlet of a filter unit 28 Upper filtrate outlet of a filter unit 30 Vent connection of a filter unit 32 Filtrate-side sterile air filter 34 Pre-filter inlet line 36 Pre-filter outlet line 38 Connecting line 40 Main filter inlet line 42 Main filter outlet line

Claims

1. A single-use device (10) for filtering a large volume of medium, comprising a plurality of single-use filter units (12), at least some of which, preferably all, are connected to each other by rigid pipes, which are formed by pressure-stable tubes having a defined diameter, wherein the filter units (12) comprise several prefilters (12a) and several main filters (12b) for virus filtration configured as hollow fiber capsules, and wherein a common outlet pipe (36) is provided for several prefilters (12a), characterized in that at least one shut-off valve is provided between the prefilters (12a) and the main filters (12b) in the outlet pipe (36), in order to be able to interconnect all main filters (12b) to a group separate from the prefilters (12a), and that a common vent pipe (20) is provided for the main filters (12b), which leads to an unfiltrate-side sterile air filter (22), so as to supply test gas to all main filters (12b) via the sterile air filter (22) through the vent pipe (20) for the performance of an integrity test of all main filters (12b).

2. The single-use filtration device (10) according to claim 1, characterized in that a rigid pipe from a pressure-stable tube having a defined diameter is provided between the prefilters (12a) and the main filters (12b), and / or in that an inlet pipe (40) to the main filters (12b) is configured as a rigid pipe from a pressure-stable tube having a defined diameter.

3. The single-use filtration device (10) according to any of the foregoing claims, characterized in that a common outlet pipe (36, 42) for the several prefilters (12a) and / or for the several main filters (12b) is a rigid pipe, which is formed by a pressure-stable tube having a defined diameter.

4. The single-use filtration device (10) according to any of the foregoing claims, characterized in that it has both a common inlet connection (16) and a common outlet connection (18) for the medium and can be integrated into a filtration branch by means of sterile connectors.

5. The single-use filtration device (10) according to any of the foregoing claims, characterized in that the filter units (12) and the rigid pipes are arranged such that all prefilters (12a) and all main filters (12b) are each exposed to a flow in parallel.

6. The single-use filtration device (10) according to any of the foregoing claims, characterized in that the prefilters (12a) are designed for dead-end filtration and the main filters (12b) for cross-flow filtration.

7. The single-use filtration device (10) according to any of the foregoing claims, characterized in that some of the rigid pipes are formed by common housings of filter units (12).

8. The single-use filtration device (10) according to any of the foregoing claims, characterized in that at least one filter unit (12) is configured as a multiple capsule having at least two identical or different filter elements installed in the common housing, wherein the multiple capsule preferably has at least one pleated filter element and one hollow fiber filter element.

9. The single-use filtration device (10) according to claim 8, provided it does not refer back to claim 5, characterized in that the filter elements are arranged so as to be exposed to a sequential flow.

10. The single-use filtration device (10) according to any of the foregoing claims, characterized in that a pressure-stable sight glass is integrated in the vent pipe (20) and / or that at least one indicator is arranged in the vent pipe (20), which reacts to water, and / or that a protective filter for protecting the air filter (32) is interposed between the vent connection (20) and the input of the air filter (32), and / or wherein a releasable vent valve is provided in the vent pipe (20) or on the sterile air filter (22).

11. The single-use filtration device (10) according to any of the foregoing claims, characterized in that at least one filter unit (12), preferably all main filters (12b), is oriented so as to be exposed to a flow from bottom to top, wherein preferably the at least one filter unit (12) has a lower unfiltrate inlet (24) as well as a lower filtrate outlet (26) and an upper filtrate outlet (28) as well as an upper vent connection (30), wherein further preferably valves for blocking the lower unfiltrate inlets (24) and for blocking the vent connections (30) are provided.

12. The single-use filtration device (10) according to any of the foregoing claims, characterized in that a flow-reducing element is provided at an outlet of a filter unit (12) or of a group of filter units (12) to produce a differential pressure for a flushing process.

13. The single-use filtration device (10) according to any of the foregoing claims, characterized by a connection on the filtrate side of the device (10) to which a filtrate-side sterile air filter (32) can be connected through which gas can be pumped after completion of a filtration for discharging filtrate remaining in the device (10).

14. A method for performing an integrity test in a single-use filtration device (10) as defined in claim 1 for filtering a large volume of medium, wherein the single-use filtration device (10) comprises several prefilters (12a), several main filters (12b) for virus filtration configured as hollow fiber capsules and a common outlet pipe (36) for the several prefilters (12a), wherein a shut-off valve is provided between the prefilters (12a) and the main filters (12b) in the outlet pipe (26), wherein the main filters (12b) have vent connections on their upper front sides which flow into a common vent pipe (20), which leads to an unfiltrate-side sterile air filter (22), and wherein the method comprises the following steps: grouping of all main filters (12) separately from the prefilters (12b), by closing the shut-off valve to block the main filters (12a) from the prefilters, and supplying test gas to all main filters (12a) via the sterile air filter (22) through the vent pipe (20).