Dura-Line India Pvt. Ltd. (Dura-line) had sued Jain Irrigation Systems Ltd. (JISL) in 2012 before the Delhi High Court, claiming JISL had been infringing its patented invention relating to a pipe system designed for accurate underground detection and early leakage identification since 2007. The invention was especially critical for utility applications like water, sewerage, and gas lines.

Legal Dispute

Dura-Line asserted that JISL’s products, namely B-Sure PE/PP Sewerage Pipes and Jain Insta Tracer Pipes, incorporated Dura-Line’s invention’s patented configuration.

JISL denied infringement and sought revocation of the suit patent, citing lack of novelty, inventive step, insufficient disclosure, vague claims, and fraud in securing the patent. Dura-Line also alleged design infringement of its registered design, which JISL refuted.

The Court’s findings include the following key observations:

Ownership of the Patent and Design: In the absence of any evidence to the contrary provided by JISL, the Court held that Dura-Line is the rightful proprietor of the patent and the registered design.

Novelty: JISL presented multiple prior art references, including several U.S. patents and a National Highways Authority of India (NHAI) tender document, to argue that Dura-Line’s invention was anticipated, and thus not novel. However, the Court found that no single reference fully disclosed the claimed invention, thus rejecting the novelty challenge.

Inventive step: Referring to F. Hoffmann-La Roche Ltd. v Cipla Ltd., the Court held that although some elements were known individually, their specific integration for fluid transport with leak detection was not obvious to a person skilled in the art (PSITA) from prior art, satisfying the inventive step requirement.

Insufficiency and unclear claims: The Court refuted JISL’s argument of insufficient disclosure, emphasizing that the law does not require exhaustive descriptions, but rather requires that the description should enable a PSITA to reproduce the invention.

Fraud: The Court dismissed JISL’s allegations of fraud due to a lack of evidence.

Infringement: The Court held that JISL’s products infringed Dura-Line’s patent as the products incorporated all distinct elements from the patent. The Court, further, dismissed JISL’s contention that their manufacturing process differed, stating that patent infringement is judged based on the product’s features, not how they are made. Furthermore, JISL’s brochures and expert testimony indicated that Dura-Line’s suit patent was infringed.

However, the Court rejected Dura-Line’s design infringement allegations against JISL, since Dura-Line’s claims centered around structural and technical similarities rather than visual imitation. Moreover, the Court observed no compelling visual similarity between the suit design and JISL’s product.

Though Dura-Line’s patent had expired by July 2023, the Court held that Dura-Line was entitled to relief for past infringement. It issued a decree for infringement, appointed a Local Commissioner to examine JISL’s profit accounts from April 20, 2010, up until the suit patent’s expiry and ordered JISL to furnish detailed profit statements.

Full costs were awarded to Dura-Line due to the technical complexity and prolonged duration of the litigation. The Court also directed the Registry to forward a copy of the judgment to the Controller General of Patents and issue a certificate of validity under Section 113, which allows patentees to use the court’s finding of validity in future proceedings of the Patents Act.

The Delhi High Court’s judgment reinforces the distinction between patent and design law, higher thresholds for anticipation and obviousness, the importance of technical disclosure and evidentiary standards in patent revocation, and the ability to claim damages for expired patents where infringement occurred during their term.