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EP-4736983-A1 - FILTRATION DEVICE FOR FILTERING A MEDIUM, METHOD OF ASSEMBLING A FILTRATION DEVICE, AND METHOD OF CONDUCTING A FILTRATION PROCESS

EP4736983A1EP 4736983 A1EP4736983 A1EP 4736983A1EP-4736983-A1

Abstract

A filtration device (10) for filtering a medium, in particular a small-scale filtration device for the production and/or processing of biopharmaceuticals, comprises: a top cover (12) having an unfiltrate inlet (14) and a bottom cover (16) having a filtrate outlet (18), and a plurality of filter supports (28), arranged as a stack between the top cover (12) and the bottom cover (16) along a vertical axis. Each filter support (28) is provided with a flat filter (24), especially a membrane. Each flat filter (24) is sealed to the filter support (28) with a filtrate side facing the respective filter support (28) and an unfiltrate side facing away from the respective filter support (28). The filtration device further comprises one or more intermediate elements (30), preferably one or more intermediate plates. A first intermediate element (30) is arranged between the stacked filter supports (28), dividing the filter supports (28) into an upper group (32) above the intermediate element (30) and a lower group (34) below the intermediate element (30). The first distribution flow paths lead from the unfiltrate inlet (14) to all unfiltrate sides of the flat filters (24) of the upper group (32). The first intermediate element (30) has a structure that blocks the first distribution flow paths from reaching the unfiltrate sides of the flat filters (24) of the lower group (34) and provides first collecting paths for collecting the medium that has passed through the flat filters (24) of the upper group (32). Second distribution flow paths lead from the first collecting paths to all unfiltrate sides of the flat filter(s) (24) of the lower group (34). Second collecting paths collect the medium that has passed through the flat filter(s) (24) of the lower group (34).

Inventors

  • Jakob, Fabian
  • FRIESE, THOMAS
  • MEYER, TIM

Assignees

  • Sartorius Stedim Biotech GmbH

Dates

Publication Date
20260506
Application Date
20241105

Claims (15)

  1. A filtration device (10) for filtering a medium, in particular a small-scale filtration device for the production and/or processing of biopharmaceuticals, the filtration device (10) comprising a top cover (12) having an unfiltrate inlet (14) and a bottom cover (16) having a filtrate outlet (18), and a plurality of filter supports (28), arranged as a stack between the top cover (12) and the bottom cover (16) along a vertical axis, each filter support (28) being provided with a flat filter (24), especially a membrane, each flat filter (24) being sealed to the filter support (28) with a filtrate side facing the respective filter support (28) and an unfiltrate side facing away from the respective filter support (28), the filtration device (10) further comprising one or more intermediate elements (30), preferably one or more intermediate plates, a first intermediate element (30) being arranged between the stacked filter supports (28), dividing the filter supports (28) into an upper group (32) above the first intermediate element (30) and a lower group (34) below the first intermediate element (30), first distribution flow paths leading from the unfiltrate inlet (14) to all unfiltrate sides of the flat filters (24) of the upper group (32), the first intermediate element (30) having a structure that blocks the first distribution flow paths from reaching the unfiltrate sides of the flat filters (24) of the lower group (34) and provides first collecting paths for collecting the medium that has passed through the flat filters (24) of the upper group (32), second distribution flow paths leading from the first collecting paths to all unfiltrate sides of the flat filter(s) (24) of the lower group (34), second collecting paths for collecting the medium that has passed through the flat filter(s) (24) of the lower group (34).
  2. The filtration device according to claim 1, characterized in that all or several of the filter supports (28) are provided on disc-shaped filter support plates (22) which are stacked between the top cover (12) and the bottom cover (16), wherein preferably one filter support (28) is provided on the upper side of each filter support plate (22) and another filter support (28) is provided on the lower side of each filter support plate (22).
  3. The filtration device according to claim 1 or 2, characterized in that one filter support (28) is provided on the lower side of the top cover (12) and/or on the upper side of the bottom cover (16).
  4. The filtration device according to any of the preceding claims, characterized in that the filter supports (28) provide flow paths leading to at least one vertical filtrate collection channel (26) formed by corresponding openings of the filter supports (28), the first intermediate element (30) providing a horizontal barrier in the vertical filtrate collection channel (26) forcing the medium collected by the filter supports (28) of the upper group (32) in an upper portion of the vertical filtrate collection channel (26) above the horizontal barrier to flow to the second distribution flow paths.
  5. The filtration device (10) according to claim 4, characterized in that the second collecting paths are at least partially provided by the filter support(s) (22) of the lower filter supports (28) and lead to a lower portion of the vertical filtrate collection channel (26) below the horizontal barrier, and/or provided by a second intermediate element (30) arranged between the lower group (34) and a further group of filter supports (28) below the second intermediate plate.
  6. The filtration device (10) according to any of the preceding claims, characterized in that at least some of the filter supports (28) are shaped identically, preferably all of the filter supports (28) of the upper group (32) and/or all of the filter supports (28) of the lower group (34).
  7. The filtration device (10) according to any of the preceding claims, characterized in that the flat filters (24) of the upper group (32) have characteristics different from the characteristics of the flat filters (24) of the lower group (34), especially with respect to nominal pore size and/or nominal filter retention and/or nominal volume flow.
  8. The filtration device (10) according to any of the preceding claims, characterized in that at least some of the flat filters (24) are shaped identically, preferably the flat filters (24) of the upper group (32) and/or the flat filters (24) of the lower group (34).
  9. The filtration device (10) according to any of the preceding claims, insofar as they refer to claim 2, characterized in that the top and bottom covers (12, 16), the filter support plates (22) and the intermediate element(s) (30) have outer welding sections welded to each other so as to form a closed and rigid outer housing portion of the filtration device (10).
  10. The filtration device (10) according to any of the preceding claims, insofar as they refer to claim 2, characterized in that the top and bottom covers (12, 16) and the filter support plates (22) have a circular outer periphery with similar outer diameters with respect to the vertical axis.
  11. The filtration device (10) according to any of the preceding claims, characterized in that at least one of the intermediate elements (30) provides a venting means, the venting means including a venting passage (38) and preferably further including a valve, the venting passage (38) preferably being formed at the outer periphery of the intermediate element (30), an inlet of the venting passage (38) is sealed with a hydrophobic membrane (40).
  12. The filtration device (10) according to any of the preceding claims, characterized in that at least one of the intermediate elements (30) provides, or is connected to, a sampling port.
  13. A method of assembling a filtration device (10) according to any of the preceding claims for a desired filtration process to be conducted with the filtration device (10), characterized by the following steps: - determining a number of filtration stages required by the filtration process; - determining a number of different groups (32, 34) of filter supports (28), each group (32, 34) corresponding to one of the filtration stages; - determining a number of intermediate elements (30) based on the number of different groups (32, 34); - selecting a suitable flat filter type for each group (32, 34); - determining a total filter area for each group (32, 34); - determining a number of flat filters (24) and a number of filter supports (28) based on the respective total filter area for each group (32, 34); - sealing the flat filters (24) onto the filter supports (28) of the respective group (32, 34); - building a stack of the filter supports (28) of each group (32, 34); and - stacking the groups (32, 34) with the intermediate element(s) (30) inserted between the groups (32, 34) in an order corresponding to an order of the filtration stages.
  14. The method according to claim 13, characterized either by the following further steps: - welding the filter support plates (22) and the intermediate element(s) (30) together; - welding an uppermost filter support plate (22) to the top cover (12) and/or welding a lowermost filter support plate (22) to the bottom cover (16); or characterized by the following further step: - inserting the filter support plate(s) (22) and the intermediate element(s) (30) between the groups (32, 34) of the filter supports (28) into a housing, the housing including the top cover (12) and the bottom cover (16).
  15. A method of conducting a filtration process using a filtration device (10) according to any of claims 1 to 12, characterized in that the filtration process is or includes one of the following: sterile filtration, virus filtration (pre- and main filtration), redundant sterile filtration, multi-stage filtration, cell clarification, and depth filtration.

Description

The invention relates to a filtration device for filtering a medium, in particular a small-scale filtration device for the production and/or processing of biopharmaceuticals. The invention also relates to a method of assembling such a filtration device, and to a method of conducting a filtration process using such a filtration device. In the field of filtration, especially within biopharmaceutical processes, it is common to require the use of various filter types in combination to achieve the desired purity, concentration, or quality of the filtered medium. Depending on the specific filtration task, different filters are used in sequence, e.g., depth filters for good retention of larger particles, followed by filters for reducing bioburden or sterile filters. The combination and arrangement of these filters are highly dependent on the characteristics of the medium to be filtered and can vary according to customer needs and the particular process. Up to now, the solution to this need involved connecting different filters in series using hoses or pipes with connectors, which leads to complicated assemblies that had to be manually assembled and, in many cases, had to be validated at significant expense. Connection points are always weak points within the filtration setup as they must maintain sterility, handle the necessary pressure, and be leakproof. Every connection point introduces the possibility of malfunction during the process. Furthermore, the known complex assemblies increase the total enclosed volume (known as holdup volume), which is the volume of liquid retained within the system. Holdup volume is a critical factor in biopharmaceutical filtration because the media used are often very expensive. Reducing residual liquid left inside the filtration devices is therefore essential. In combination with new therapeutic options, which are sometimes developed on a user-specific basis, this results in very small batch volumes that can barely be processed with conventional filtration systems, as these batch volumes may be smaller than the holdup volume of the system. In response to these issues, developments in the market have aimed to optimize holdup volume through developments such as flat filters mounted on filter support plates, rather than using pleated elements in capsules. Another approach combines different filters within a single unit to eliminate the need for connectors. Hose connections, in particular, can be problematic at higher process or testing pressures. Filtration systems that are designed without hose connections, such as preassembled, pre-sterilized, and self-contained systems as described, for example, in WO 2018/215246 A1 or WO 2022/074151 A1, are already known, allowing setups to be realized in a space-saving manner and minimizing possible defects. However, such assembled, pre-sterilized, and self-contained systems are typically constructed and designed for large medium volumes to be filtered. Minimizing the holdup volume plays only a minor role. Also known are systems with filter cassettes that are secured in a holder and can be operated in different zones that are separated from each other by intermediate plates. These are systems that are not closed and do not work without a holder. Further known are filtration devices constructed from support plates that guide the medium through a sealed membrane and collect the filtered medium at the outlet. These filter elements come in different designs, with variations in how the medium flows, e.g., the filtered medium can be bundled centrally or in a peripheral region of the device. WO 2019/020467 A1 shows a filtration system that combines two filter capsules in one housing, allowing, e.g., a pre-filter and a main filter to be combined into a single device. However, these capsules use pleated membranes and have a relatively high dead volume, making them unsuitable for very small batch volumes. WO 2019/243289 A1 presents an approach involving the stacking of membranes with different filtration or cleaning functions. This system, configured in a cassette format, uses cassettes fixed in a holder, with individual filter modules divided by "separation interfaces". Likewise, this filter module design is large and has a high dead volume, as well as requiring complex assembly that poses additional challenges to maintaining sterility. The object of the invention is to address the shortcomings explained above. The solution is provided by a filtration device according to claim 1, by a method of assembling such a filtration device according to claim 14, and by a method of conducting a filtration process using such a filtration device according to claim 17. Advantageous and expedient embodiments are apparent from the dependent claims. The invention provides a filtration device for filtering a medium, in particular a small-scale filtration device for the production and/or processing of biopharmaceuticals. The filtration device comprises: a top cover having a