Brita SE (Claimant) v Wessper Sp. z o.o. (Defendant)
UPC-CFI-779/2024 (Düsseldorf LD), decision of 16 April 20261
Brita sued Wessper for infringement of EP1748830, which concerns water-filter jugs and cartridges. Wessper’s cartridges are compatible with Brita’s system and were marketed as such by Wessper. Brita argued that Wessper’s supply of these cartridges indirectly infringed the patent.
Interestingly, by asserting a narrower combination of independent and dependent claims, Brita was able to capture an indirectly infringing product that arguably would not have been captured by the independent claim on its own.
Rather than relying on the broader claim 1 alone, Brita asserted the combination of claims 1 and 13 to 15. Claim 1 covered a filtration device made up of a cartridge and an inlet funnel. Claims 13 to 15 added specific features at the interface between them: an indentation in the funnel, an indentation in the cartridge, and a cartridge-side pin that engages with the funnel-side hollow body. The cartridge and jug were required to cooperate in order for the invention as defined in the asserted claim combination to be realised. In particular, the cartridge-side indentation and pin contributed to positioning the cartridge, preventing it from tilting, and forming the throttling arrangement. The narrower asserted claim combination therefore made the cartridge part of the invention in a meaningful way.
Amongst other things, a finding of indirect infringement requires that the alleged infringer supplies (or offers to supply) means relating to an “essential element” of the invention for the purpose of putting the invention into effect. The combination of Wessper’s cartridge and Brita’s jug was held to fall within the scope of the asserted claims 1 and 13 to 15 and was thus held to be suitable for putting the invention into effect. The key question was therefore whether the cartridge was an “essential element” of the invention.
The court did indeed find that the cartridge was an essential element of the invention. This followed from the asserted claim combination. The cartridge was not just a generic consumable; it was defined by several claim features and had to cooperate with the funnel-side fixing means as set out above.
The same point was important for exhaustion. Wessper argued that consumers who had bought Brita jugs were entitled to replace used cartridges, so Brita’s rights in the jugs had been exhausted. The court accepted that a filter cartridge is normally a consumable, and that replacing it will often be ordinary maintenance rather than making a new patented product.
However, in this case, features of the cartridge were a key part of the mechanism that guided the cartridge into the correct position in the jug, preventing tilting or jamming, and cooperating with the funnel-side structure to provide throttling. The cartridge therefore embodied technical effects of the asserted invention. Relevantly, the features of Wessper’s cartridge were not required when used with Wessper’s own jug.
The court held that replacing a spent Brita cartridge with Wessper’s cartridge was therefore not just the continued use of an exhausted product, but it amounted to re-making the patented combination again. The rights were therefore not exhausted for the asserted combination of claims 1 and 13 to 15.
The decision is a useful reminder that the asserted claim combination can be decisive. A dependent claim may do more than narrow the case; it may change which part of a product is treated as embodying the invention. Here, by relying on claims that placed technical features in the cartridge, Brita was able to frame the replacement cartridge as an essential element of the invention rather than as a mere consumable.
For patentees, the decision shows the value of considering dependent claims carefully when pleading indirect infringement, especially where the commercial target is a replacement part or consumable. Features in dependent claims may help connect that part to the technical contribution of the invention and support both indirect infringement and an answer to exhaustion.
For defendants, the decision shows that an exhaustion defence may be harder where the replacement part does more than restore ordinary function. If the asserted claims give that part a specific technical role in achieving the claimed effect, replacing it may be characterised as re-making the patented combination rather than simply maintaining an exhausted product.
The point may have broader significance beyond water filters. Many products depend on consumables or replaceable parts, such as cartridges, capsules, blades, sensors, batteries or refill units. Where a patent claim defines the replaceable part as contributing to the technical effect of the claimed combination, suppliers of third-party consumables may face indirect infringement risk, and exhaustion may be less straightforward.