Pullman-Ermator AB v. Dustcontrol International AB, patent invalidity etc., Svea Court of Appeal, Sweden, 27 April 2010, Case No. T 5824-08
The case concerned a patent for a filter cartridge suitable for use in the outlet of a cyclone dust separator. The filter cartridge was characterized by the filter body being partly surrounded by a collar separated from the filter by a ring slit, the filter body and the collar being joined together by an end cover. The closest prior art was a replaceable filter mounted in a metallic tube via an end cover detachably arranged in the cyclone outlet. The Court of Appeal found claim 1 anticipated as the claim did not require the filter body, the collar and the cover end to be permanently joined so that they cannot be separated without being destroyed and the person skilled in the art would understand that both alternatives are possible and covered by the claim. On the contrary, the District Court in view of the problem solved by the invention considered the filter cartridge to be a unit that neither can nor need to be taken apart and found claim 1 valid. Thus, the Court of Appeal construed claim 1 on the basis of the terms of the claim whereas the District Court made a purposive construction.
In summary, the Court of Appeal declared claim 1 invalid but upheld an amended patent in accordance with an auxiliary request corresponding to claim 2, specifying that the collar is made of a pervious or porous material. Pullman-Ermator was ordered to pay for Dustcontrol’s costs in the District Court and in the Court of Appeal.
Read the judgment (in Swedish) here.