The Delhi High Court came up with key findings in deciding the interim injunction application of the Plaintiff in Aquestia Limited vs Automat Industries Private Limited & Ors. [CS (COMM) 860/2024]. The judgment revisits foundational principles on the nature of patent rights, claim construction, and infringement analysis, particularly where the alleged infringer is a patentee of a similar product.

Aquestia had alleged infringement of their patent rights in IN 427050, entitled ‘A Fluid Control Valve’, which covered ‘Series 75 Valve’ technology. The invention relates to a fluid control valve incorporating an asymmetric sealing diaphragm, asserted to enable smoother flow and operation under low pressure.

According to the Plaintiff, the Defendants, having no prior experience in pilot-operated valves before 2020, entered the market by imitating its ‘Series 75’ valve. The Plaintiff also alleged that Defendant no. 5, formerly employed with Netafim (Plaintiff’s distributor), was directly involved in the development phase of the plaintiff’s technology covered by the suit patent and later joined the Defendant company as Chief Technical Officer, becoming one of the inventors of the Defendants’ patent, IN 478536 for a fluid control valve.

The Defendants, on the other hand, contended that their product was independently developed and covered by their own granted patent, IN’536, which they argued constituted a complete defence against any allegation of infringement. They argued that there was no commonality between the suit patent and their product, and therefore, no case of infringement could be made. It was further contended that Defendant no. 5 was only engaged in commercial functions during his tenure at Netafim, not technical design. They also raised defences of delay, non-working of the suit patent in India, and public interest owing to their supplies for infrastructure projects.

The Court emphasised the following principles in deciding the application in favour of the Plaintiff:

• Mere Grant of a Patent in Favour of the Defendant is Not a Valid Defence:

One of the principal defences raised by the Defendants in the instant case was that their impugned product “Hydromat” valve was covered under their patent IN 478536, and hence, it could not be said to infringe another patent.

The Court unequivocally rejected this contention, relying on Hindustan Lever Ltd. vs Lalit Wadhwa [2007 SCC OnLine Del 1077] and Guala Closures SPA vs AGI Greenpac Ltd. [2024 SCC OnLine Del 3510]. The Court reiterated that a patent confers only an “exclusionary right” i.e. the right to prevent others from practising the invention, not the right to practise it oneself. A patentee’s ability to use their invention may be limited by legislation or regulations. Therefore, merely because the Defendant holds a patent for its product, it cannot claim immunity from infringement of a prior and subsisting patent.

The Court emphasised that infringement analysis must still proceed by comparing the impugned product with the claims of the earlier patent, irrespective of whether the Defendant holds a patent of its own.

• Defining the Scope of the Invention: The ‘Characterised’ Portion:

In construing the suit patent, the Court reaffirmed that the crux of the invention lies in the portion of the claim following the word “characterised”. Relying on the decision in Guala Closures, the Court held that the ‘characterised’ clause demarcates the novel features forming the inventive contribution of the invention. The Court also underscored that the Complete Specification plays a sacrosanct role in interpreting claims.

• ‘Claim-to-Product’, Not ‘Product-to-Product’ Analysis:

The Court disapproved the Defendants’ ‘product-to-product’ comparative analysis, citing the Division Bench ruling in Mold Tek Packaging Ltd. vs Pronton Plast Pack (P) Ltd. [2025 SCC OnLine Del 4883]. It reiterated that infringement must be assessed by comparing the Defendant’s product with the complete specification of the suit patent, not with the Plaintiff’s product.

• Infringement Analysis: Visual Examination, Claim Mapping and Lack of Rebuttal:

The Court examined the Plaintiff’s detailed claim mapping that compared the key features of Claim 1 of the suit patent with the Defendants’ impugned “Hydromat” valve. The Court noted that the Plaintiff had provided precise measurements of the two respective areas of the diaphragm in the Defendants’ valve which demonstrated that the diaphragm was asymmetric, with the portion over the inlet path having a larger area than the portion over the outlet path.

A physical sample of the Defendants’ product was also produced before the Court. Upon visual examination, the Court observed that the diaphragm was divided by a concave rib passing through the apex, clearly creating an asymmetry between the inlet and outlet sides, one of the inventive features of the suit patent.

The Court further noted that the Defendants had not provided any rebuttal measurements or technical data to contest the Plaintiff’s mapping. Both their written statements and drawings merely depicted the radii of the inlet and outlet paths, without demonstrating the comparative diaphragm areas. The Plaintiff had furnished three-dimensional scans and measurements substantiating the claimed asymmetry.

The Court also found the Defendants’ written assertions inconsistent with their own patent specification (IN’536), which expressly stated that the curved sealing bridge made for the valve an enlarged area at the upstream side. This, the Court said, contradicted the Defendants’ position that their diaphragm was symmetrical.

Based on the comparative analysis, the Court held that, prima facie, the Defendants’ “Hydromat” valve embodied the essential features of the suit patent’s Claim 1, particularly the asymmetric sealing diaphragm and differential diaphragm surface areas.

• Infringement Analysis: Distinguishing Feature:

The Defendants sought to differentiate their valve by contending that it incorporated a curved sealing bridge, which was not covered by the suit patent. The Court rejected this argument, holding that the shape of the sealing bridge was immaterial to the question of infringement.

The Court observed that Claim 1 of the suit patent referred broadly to a “sealing bridge”, without limiting its configuration. Moreover, dependent Claim 9 of the suit patent explicitly envisaged a curved or concave sealing bridge as one of the embodiments. Therefore, the Court found the Defendants’ reliance on this feature to be contrary to the language of the suit patent.

• Findings on Defendant no. 5’s Role:

The Court also addressed the Plaintiff’s allegation that Defendant No. 5, a former employee of the Plaintiff’s distributor, had technical knowledge of the suit patent. Confidential email correspondences reviewed by the Court indicated his active participation in detailed discussions on the working of the valve and his involvement in the technological aspects of the Plaintiff’s product.

The Court found it implausible that a technically qualified person, later named as inventor in the Defendants’ patent, lacked technical exposure to the Plaintiff’s technology. This reinforced the Plaintiff’s prima facie case that the Defendants had access to and knowledge of the Plaintiff’s patented technology.

• Delay, Non-Working and Balance of Convenience

The Defendants contended that the Plaintiff delayed action despite being aware of their activities since 2022 and that the patent had not been worked in India. The Court, however, accepted the Plaintiff’s explanation that testing and investigation were delayed due to the October 2023 attacks near its Israeli facility. It also noted that invoices from 2021 evidenced sales of the patented products in India.

On balance of convenience, the Court rejected the Defendants’ reliance on Boehringer Ingelheim vs Vee Excel Drugs [3 2023 SCC OnLine Del 1889], clarifying that the “public interest” exception applies to issues relating to public health and access to a medicine at an affordable price. Continuing sales of infringing products, the Court held, would cause irreparable harm to the patentee.

Having found a strong prima facie case of infringement, irreparable harm, and balance of convenience in favour of the Plaintiff, the Court restrained the Defendants, their agents and distributors from manufacturing, selling, advertising, exporting, or otherwise dealing in any product infringing the suit patent. The Defendants were also directed to remove all listings and references to the infringing products from e-commerce and other platforms.