Nampak Products Limited and Another v Man-Dirk (Pty) Limited

The appellants, Nampak Products Limited and H L & H Timber Products (Pty) Limited, were the registered joint proprietors of South African Patent No 90/2427 for an invention titled "Pressure Resistant Bag", used primarily in underground mine support systems. The respondent, Man-Dirk (Pty) Limited, manufactured and sold a competing mine support bag. The appellants alleged that the respondent’s product infringed their patent and applied to the Commissioner of Patents for a permanent interdict restraining infringement and for delivery up of infringing products. The respondent denied infringement, contending that its product lacked one essential feature of the main patent claim, namely a "second bag" as required by the claim. The Commissioner of Patents dismissed the application, and the appellants appealed to the Supreme Court of Appeal.

The appeal was dismissed with costs, including the costs of two counsel.

The case is significant for South African patent law because it provides authoritative guidance on the limits of purposive construction in claim interpretation. It reaffirms the primacy of claim language and cautions against reliance on foreign interpretive approaches, particularly those influenced by the European Patent Convention, where they conflict with established South African principles. The judgment underscores that infringement requires the presence of all essential claim integers.