Importance of preserving both structural and process elements in claim drafting

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Overview of Dispute:
Dura-Line India Pvt. Ltd., a subsidiary of U.S.-based Dura-Line International, filed a suit before the Hon’ble Delhi High Court alleging infringement of its patent and design rights by Jain Irrigation Systems Ltd. (JISL) (CS(COMM) 245/2017 & CC(COMM) 54/2017). The dispute centered around a pipe assembly with a co-extruded tracer cable, marketed by Dura-Line as “Dura Trac,” designed for underground traceability and leak detection. The Hon’ble Court delivered its judgment in the matter on 19 May 2025.

Key IPs involved:
• Patent No. IN 199722: "A Pipe Assembly Having Traceability and Leakage Detection Features"
• Design Registration No. 192665: a detectable pipe

Trigger for Litigation:
Dura-Line discovered that Jain Irrigation had participated in a tender floated for Omkareshwar Lift Irrigation Scheme using similar products (“B-Sure PE/PP Sewerage Pipes” and “Jain Insta Tracer Pipes”)—allegedly copying Dura-Line’s patented and registered design.

Core Legal Issues:
• Patent Infringement
Whether JISL's products (“B-Sure PE/PP Sewerage Pipes” and “Jain Insta Tracer Pipes”) infringed Patent No. 199722.
• Design Infringement
Whether the same products infringed Design No. 192665.
• Validity of Patent
Whether the patent lacked novelty, inventive step, or sufficient disclosure as alleged by JISL in their counter-claim for revocation under Section 64 of the Patents Act.

The Patent: IN 199722:
The invention pertains to an pipe with a co-extruded tracer cable encased in polymer, enabling underground traceability and leak detection without compromising pipe strength. It had 11 claims, including:
• Claim 1 (Independent): Non-metallic pipe with co-extruded tracer cable on the outer surface, encased in polymer.
• Claim 9 (Method Claim): Described how to locate the pipe and detect leaks using pulses and signal reflections.

Key Findings of the Hon’ble High Court:
On Proprietorship: The Hon’ble High Court affirmed that Dura-Line was the rightful proprietor of both the patent and the registered design. Evidence, including Form 27 (2012), established commercial use under the “Dura Trac” brand.

On Jain Irrigation’s Validity Challenges:
The Hon’ble High Court rejected JISL’s counter-claims under Section 64:
1. Lack of Novelty [Sec. 64(1)(e)]: The Hon’ble High Court noticed that none of the cited prior art disclosed all key features of Claim 1 in a single document. Differences included tracer cable placement (e.g., embedded vs. surface-mounted), absence of co-extrusion, or lack of polymer encapsulation. Hence, it was held that the defendant has failed to discharge the burden of proving that Claim 1 of the Suit Patent was anticipated in its entirety by any single prior art reference. Therefore, the argument of lack of novelty under Section 64(1)(e) was rejected.
2. Obviousness [Sec. 64(1)(f)]: Applying the five-step test from F. Hoffmann-La Roche v. Cipla, the Hon’ble High Court held that the invention involved a technical advance and was not obvious to a person skilled in the art (PSA). The inventive step lay in achieving leak detection and traceability without compromising pipe strength—via co-extrusion on the pipe's exterior.
3. Insufficient Disclosure [Sec. 64(1)(h)] & Ambiguity in Claims [Sec. 64(1)(i)]: The Hon’ble High Court stated that “the specification clearly sets out the invention’s essential features and describes its working in a manner that allows the PSA, equipped with common general knowledge, to implement it effectively. Further, the claims are clearly worded and fairly based on the disclosure contained in the specification. There is no inconsistency between the claimed subject matter and the technical teaching of the specification. “

On Infringement:
• Patent Infringement Established: The Hon’ble High Court observed that although the Plaintiff did not press its method claims at the final hearing, the core issue of infringement centered around Claim 1 of the Suit Patent. The Defendant argued that their products did not replicate the patented configuration, particularly the requirement of a co-extruded tracer cable on the outer surface. However, the Hon’ble High Court held that the manner in which the tracer wire was affixed—whether strictly co-extruded or applied by another technique—was immaterial, so long as the final structure embodied the essential features of the claimed invention. It was further held that the Defendants’ products, as marketed and described, did incorporate the combination of elements specified in the patent, including a non-metallic pipe, a tracer cable, and polymeric encasement. Accordingly, the Hon’ble High Court concluded that the Defendants’ products infringe the Suit Patent IN 199722.
• Design Infringement Not Established: The Hon’ble High Court rejected Dura-Line's claim of design infringement, holding that it failed on three key grounds: (i) the specific features asserted by the Plaintiff were found to fall outside the scope of protection under the Designs Act, as they were functional rather than ornamental; (ii) Dura-Line did not adequately prove that Jain Irrigation’s product visually imitated or copied the registered design; and (iii) upon visual comparison, the Defendant’s product did not appear deceptively similar to the registered design. As a result, the Hon’ble High Court ruled Issue No. (iv) in favour of the Defendant and dismissed the design infringement claim.

Takeaways:
• The Hon’ble High Court’s careful application of the five-step inventive step test affirms that co-extrusion of tracer cables in the outer pipe surface was a non-obvious improvement deserving protection.
• The decision underscores that technical procurement documents (like tenders) may not qualify as prior art unless they clearly teach or enable an invention.

Author : Nitin Patel
Designation: Patent Attorney