Patent applicants sometimes discover that their most formidable opponent in proving an inventive step is not a competitor’s technology but their own earlier patent filings. Fourteen years after a mixing device was first filed for protection, its applicant learned this lesson twice: once before the patent office, and again before a Division Bench of the Delhi High Court.<\/p>\n
Sulzer Mixpac AG (“Sulzer Mixpac”), a Swiss manufacturer, had applied on 1 May 2012 for a patent titled “Static Mixer,” a device used to blend molten polymers as they pass through an injection-molding process, via Application 1329\/DEL\/2012. The invention consisted of multiple installation bodies arranged inside a tubular mixing housing, connected to each other through bar elements, an arrangement designed to maintain low internal pressure despite very thin valve walls. A First Examination Report was issued on 22 May 2019, and after Sulzer Mixpac’s reply and a Subsequent Examination Report, the Assistant Controller of Patents and Designs (“ACPD”) rejected the application by order dated 10 March 2021, finding it anticipated by four prior art documents, D1 to D4, several of which belonged to Sulzer Mixpac’s own patent family. Sulzer Mixpac’s statutory appeal under Section 117A(2) of the Patents Act, 1970 (“Patents Act”) was dismissed by a Single Judge on 5 April 2024, prompting the present Letters Patent Appeal (“LPA”).<\/p>\n
The court noted that the preliminary objection to maintainability rested on treating a judgment under Section 117A(2) of the Patents Act as equivalent to a civil court’s decree, from which no further appeal could lie. The court observed that this premise did not hold, since an earlier Division Bench ruling had already settled that the bar on further appeals applies only where the order under appeal originates from a civil court, and a statutory authority such as the Controller of Patents does not carry the trappings of one. The court held that the same reasoning, developed in the trademark context, applied with equal force to appeals under the Patents Act, and the Letters Patent Appeal was accordingly maintainable.<\/p>\n
The court found no merit in the submission that the five-step obviousness framework from the Roche<\/em> precedent had to be applied mechanically. The court reasoned that the five steps offer a structured method for assessing inventive step, but adjudication under the Patents Act remains governed by the statute itself, not by a rigid checklist. The court stated that where a case can fairly be decided without walking through each step in sequence, the outcome is not vitiated on that ground.<\/p>\n On the substantive question, the court observed that the ACPD’s findings on obviousness deserved to be sustained. The court noted that prior art document D1, part of Sulzer Mixpac’s own patent portfolio, disclosed connection elements joining installation bodies and expressly taught arrangements extending to twelve installation bodies through a common connecting structure, closely mirroring the claimed feature. The court observed that where the inventor of the prior art and the subject application are the same, the distance between what was already disclosed and what is now claimed narrows considerably, since a skilled person is presumed to draw naturally on that inventor’s own earlier teachings.<\/p>\n The court further observed that D2 and D3 depicted reinforced strips performing an equivalent connecting function across more than five installation bodies, and D4 disclosed a common connecting element joining multiple mixing elements, reinforcing that the claimed arrangement was an obvious extension rather than an inventive leap. The court held that all essential features of the subject invention stood anticipated by D1 alone, and the remaining prior art independently corroborated the absence of an inventive step under Section 2(1)(ja) of the Patents Act.<\/p>\n The court opined that comparing the invention with an unrelated European patent, rather than with the cited prior art, could not establish inventiveness, since the relevant benchmark is the prior art actually cited against the application. The court also noted that the argument on the number of fluid streams had not been raised at the examination stage and was not identified as a defining feature in the specification itself. The court stated that no comparative data existed to demonstrate any surprising technical advantage from connecting more than five installation bodies through a common bar element, leaving the claimed improvement resting on assertion rather than evidence.<\/p>\n In view of the observations and the arguments presented by both the parties, the Delhi High Court held that:<\/p>\nAn Inventor Competing With Itself<\/h3>\n
No Data to Show a Surprising Effect<\/h3>\n
Findings<\/h2>\n
\n
\n