Sulzer Mixpac AG v. Assistant Controller of Patents and Designs

High Court of Delhi at New Delhi, Division Bench | Date of Decision: July 1, Case Number: LPA 545/2024 Bench: Hon’ble Mr. Justice C. Hari Shankar and Hon’ble Mr. Justice Om Prakash Shukla

BACKGROUND

The Appellant, Sulzer Mixpac AG, filed Application No. 1329/DEL/2012 on 1 May 2012 before the Controller of Patents seeking registration of a patent for an invention titled “Static Mixer” (referred to as “the subject invention”). The subject invention relates to a plastic static mixer with an installation body used to mix molten polymers injected via injection molding machines, installed within a tubular mixing housing; because mixing must occur repeatedly, the invention comprises several installation bodies arranged one behind another. The mixer is approximately 30 mm in length with thin valves up to 3 mm thick and because such thin valves would ordinarily be unable to withstand the high pressure of fluid injected via the injection molding machine, multiple installation bodies are used within the static mixer, connected to each other via bar elements, allowing fluid to move between installation bodies while maintaining internal tool pressure below one thousand bars. A similar arrangement was previously known in European Patent EP’1426099 (“EP’099”), whose Figure 15 disclosed a static mixer with a maximum of five installation bodies (47A to 47E) connected by a single common bar element (54). The Appellant’s claimed novel and inventive feature, per paragraph 5(x) of the appeal, was the ability to connect more than five installation bodies to one another via a common bar element, said to yield technical advantages including improved homogeneity, greater mixer length due to lower internal pressure and increased stiffness reducing breakage tendency.

Following the application, a First Examination Report (“FER”) was issued on 22 May 2019, to which the Appellant replied on 17 June 2019; a Subsequent Examination Report (“SER”) was then issued by the Assistant Controller of Patents and Designs (“ACPD”) on 1 February 2021, to which the Appellant filed written submissions on 4 March 2021. By order dated 10 March 2021, the ACPD rejected the application, accepting the Appellant’s submissions on all objections raised in the SER except the objection concerning novelty/inventive step under Sections 2(1)(j) and 2(1)(ja) of the Patents Act, 1970. The ACPD held that prior art documents D1 to D4 anticipated the claimed features – in particular, that D1 (EP2181827A2/US20100097883A1) disclosed connection elements (14, 15, 114, 115) mechanically equivalent to the claimed common bar elements and that paragraphs 71, 74 and 75 of D1 taught arrangements of up to 12 installation bodies connected via such elements; that D3 disclosed reinforced strips equivalent to the common bar, accommodating more than five installation bodies in certain drawings; that D2 disclosed more than five installation bodies in its Figure 1; and that D4 disclosed a common connecting element (35) mechanically equivalent to the claimed bar element. On this basis, the ACPD held the claimed invention neither novel under Section 2(1)(j) nor inventive under Section 2(1)(ja) and rejected the application.

The Appellant challenged the ACPD’s order by way of CA (Comm. IPD-PAT) 19/2021 under Section 117A(2) of the Patents Act, 1970, which was dismissed by a learned Single Judge of the Delhi High Court by judgment dated 5 April 2024. The Single Judge held that the prior art revealed and taught the possibility of multiple installation bodies connected through a mechanical equivalent of a common bar element (including in the form of a reinforced wall), that merely encasing installation bodies to permit fluid flow for mixing did not constitute an inventive step, that the Appellant’s argument regarding fluid flowing through the common bar element (as opposed to prior art) was not persuasive since fluid must fundamentally flow through the installation bodies regardless and that no comparative data had been provided regarding the appellant’s separate claim of reduced pressure loss as against prior art documents D1-D4 (only a comparison with EP’099 having been furnished). The present Letters Patent Appeal (“LPA”) was filed challenging the Single Judge’s judgment.

ISSUES FOR DETERMINATION

1. Whether a Letters Patent Appeal is maintainable against a judgment of a Single Judge of the High Court rendered under Section 117A(2) of the Patents Act, 1970 or whether such an appeal is barred (as contended by the Respondent), by analogy to the bar on second appeals under Section 100A of the Code of Civil Procedure, 1908.
2. Whether the learned Single Judge erred in law by not following, sequentially, the five-step test for assessing obviousness/inventive step articulated in F Hoffmann-La Roche Ltd v. Cipla Ltd.
3. Whether the subject invention – specifically, the connection of more than five installation bodies via a common bar element in a static mixer – involved an inventive step over prior art documents D1 to D4 and was accordingly patentable as an “invention” within the meaning of Sections 2(1)(j) and 2(1)(ja) of the Patents Act, 1970.

KEY HOLDINGS OF THE COURT

1. On maintainability, the Court held that the appeal was maintainable, applying the ratio of the Division Bench decision in Promoshirt SM SA v. Armasuisse (2023 SCC OnLine Del 5531), which had held, in the context of an appeal under Section 91 of the Trade Marks Act, 1999, that the bar on further appeals under Section 100A of the CPC applies only to appeals against decrees or orders of a “civil court” as defined under Section 2(14) CPC and that a quasi-judicial authority such as the Registrar of Trade Marks (and, by parity of reasoning, the ACPD under the Patents Act) does not qualify as a “civil court” for this purpose, even applying a “trappings of a court” test. The Division Bench held that the ratio of Promoshirt applied mutatis mutandis to appeals against ACPD orders under Section 117A(2) of the Patents Act and accordingly rejected the Respondent’s preliminary objection to maintainability.
2. On the five-step test in F Hoffmann-La Roche Ltd v. Cipla Ltd (225 (2015) DLT 391 (DB)), the Court held that the five steps for assessing obviousness enumerated in paragraph 120 of that judgment are guidance for how a court may proceed in a given case, not mandatory sequential requirements (“commandments cast in stone”) that must be strictly followed in every case; where a case is capable of being decided without rigidly applying all five steps, the decision is not vitiated solely for that reason. The Court accordingly rejected the Appellant’s contention that the Single Judge’s judgment was vitiated for not having applied the Roche steps seriatim.
3. On the substantive question of inventive step, the Court held that the ACPD’s reasoning in the order dated 10 March 2021 was “unexceptionable.” The Court found that the Appellant’s own case (as set out in paragraph 5(x) of the LPA and in the comparison chart annexed to its written submissions) identified only two features distinguishing the subject invention from prior art D1-D4: (i) the presence of a common bar element interconnecting all installation bodies and (ii) the number of streams into which each installation body divides fluid flow. As to the second feature, the Court held that this had not been raised by the Appellant at the examination stage (in its reply to the FER or written submissions on the SER) and was not, even per the Appellant’s own complete specification, among the prime features of the subject invention and the Court declined to allow it to be raised for the first time at this stage.
4. As to the first (and central) feature – connection of more than five installation bodies via a common bar element – the Court held, upon examining Figure 4 of D1 (together with paragraphs 71, 74 and 75 of D1, which taught connection of up to 12 installation bodies via a common connection element), Figures 11 and 12 and Drawings 1, 5 and 6 of D3 and Figure 1 of D2, that these prior art documents clearly disclosed multiple installation bodies connected via a single common connecting element (whether termed a bar element or reinforced strip) and that the use of a bar element in place of a reinforced strip would be obvious to a person skilled in the art. The Court gave particular weight to the fact that the primary prior art document, D1, was itself an invention of the Appellant, reasoning that the leap from an inventor’s own prior art to a subsequent claimed invention is “much more easily scaled” and correspondingly less likely to embody a genuine inventive step. The Court held that the Appellant’s submitted comparison chart itself did not establish any point of novelty beyond the bar-element and stream-number features and that the bar-element feature was anticipated by D1.
5. Accordingly, the Court held that what the Appellant had done, in proceeding from its own prior art documents (particularly D1) to the subject invention, was a mere modification using disclosures and teachings already available in the prior art and did not constitute an inventive step under Section 2(1)(ja) of the Patents Act, such that the subject invention was not patentable as an “invention” under Section 2(1)(j).
6. Final operative order: The Court found no error in the Single Judge’s decision upholding the ACPD’s rejection of the Appellant’s patent application and dismissed the appeal.

STATUTORY PROVISIONS INVOLVED

Section 2(1)(j) of the Patents Act, 1970, defining “invention” as “a new product or process involving an inventive step and capable of industrial application,” was the foundational provision determining patentability; the Court held the subject invention did not qualify as an “invention” for want of an inventive step.

Section 2(1)(ja) of the Patents Act, 1970, defining “inventive step” as “a feature of an invention that involves technical advance as compared to the existing knowledge or having economic significance or both and that makes the invention not obvious to a person skilled in the art,” was the specific standard applied by both the ACPD and the Court in assessing and ultimately rejecting the claim of non-obviousness, given that the connection of more than five installation bodies via a common bar/connecting element was found to be disclosed or rendered obvious by prior art documents D1 to D4.

Section 117A of the Patents Act, 1970 (reproduced in the judgment), governing appeals to the High Court from decisions of the Controller under specified provisions of the Act, was the basis of the original statutory appeal (CA (Comm. IPD-PAT) 19/2021) decided by the Single Judge and sub-section (2) thereof was the specific provision under which that appeal had been brought.

Section 100A of the Code of Civil Procedure, 1908 (reproduced in the judgment), barring further appeals from a judgment and decree of a Single Judge of a High Court hearing an appeal from an original or appellate decree or order, was the provision invoked by the Respondent to challenge maintainability of the present LPA; the Court held, following Promoshirt, that this bar applies only where the order under appeal before the Single Judge originated from a “civil court” as defined in Section 2(14) CPC, which the ACPD (like the Registrar of Trade Marks in Promoshirt) is not.

Section 91 of the Trade Marks Act, 1999, under which the appeal in Promoshirt SM SA v. Armasuisse had been brought before the Single Judge in that case, was referenced as the statutory analogue whose appellate maintainability reasoning was extended by the Division Bench to the present Patents Act context.

REASONING OF THE COURT

On maintainability, the Court’s reasoning was one of direct application of binding intra-court precedent: since the Division Bench in Promoshirt had already determined, after detailed analysis, that Section 100A CPC’s bar on further appeals applies only to orders originating from a “civil court,” and that a quasi-judicial statutory authority such as the Registrar of Trade Marks does not meet that description even under a “trappings of a court” test, the Court reasoned that there was no principled basis to distinguish the ACPD (a similarly constituted quasi-judicial patent authority) from the Registrar of Trade Marks for this purpose and accordingly applied Promoshirt’s ratio mutatis mutandis without need for independent re-analysis.

On the Roche five-step test, the Court’s reasoning was rooted in a distinction between statutory adjudicatory standards and judicially formulated analytical aids: since the Patents Act itself, not the Roche judgment, is the source of the legal standard for inventive step, the five steps in Roche were characterized as interpretive guidance for structuring the inquiry in appropriate cases rather than a mandatory checklist whose omission is per se fatal to a judgment’s validity. The Court reasoned that where the outcome is sustainable on the substance of the comparison between the claimed invention and prior art, formal non-adherence to the five-step sequence does not vitiate the decision.

On the substantive inventive-step question, the Court’s reasoning proceeded by first isolating, from the Appellant’s own pleaded case and comparison chart, precisely which features were claimed as distinguishing the subject invention from prior art – finding these to be only the common-bar-element connectivity feature and (belatedly and impermissibly raised) the stream-division feature. Having narrowed the inquiry to the bar-element feature, the Court engaged directly with the technical disclosures in D1, D2 and D3 (reproducing the relevant figures/drawings), reasoning that these documents, on their face and read together with their accompanying textual disclosures (particularly paragraphs 71, 74 and 75 of D1, which expressly taught arrangements of up to 12 installation bodies via a common connecting element), anticipated the core connectivity feature claimed as novel. The Court reasoned further that even where the prior art used a differently named or configured connecting structure (e.g., a “reinforced strip” rather than a “bar element”), the substitution of one mechanically equivalent connecting structure for another would be an obvious modification to a person skilled in the art, particularly significant here because the same inventive entity (the Appellant) authored both the prior art (D1) and the subject invention, which the Court treated as reducing the inventive distance that would need to be bridged to render the later application obvious. This reasoning led the Court to conclude that the subject invention represented, at most, an incremental modification drawing on the Appellant’s own prior disclosures rather than a genuine inventive step and thus that the ACPD’s and Single Judge’s conclusions were correctly reached.

DOCTRINAL SIGNIFICANCE

Within the bounds of what was actually decided, this judgment makes two distinct doctrinal contributions. First, on procedure, it extends the Division Bench’s ratio in Promoshirt SM SA v. Armasuisse – originally articulated in the trade mark appeal context under Section 91 of the Trade Marks Act, 1999 – to hold that Letters Patent Appeals are maintainable against judgments of a Single Judge rendered in appeals under Section 117A(2) of the Patents Act, 1970, since the ACPD, like the Registrar of Trade Marks, is not a “civil court” for purposes of the Section 100A CPC bar on further appeals. This clarifies appellate procedure specifically for patent appeals and confirms that the reasoning developed in the trade mark registration context applies with equal force to patent prosecution appeals. Second, on inventive step, the judgment reaffirms that judicially formulated analytical frameworks such as the five-step Roche test are interpretive tools rather than binding procedural mandates and that a decision on obviousness is not vitiated merely for not having tracked such a framework step-by-step, provided the substance of the comparison between the claimed invention and prior art is properly undertaken. The judgment also illustrates, on its facts, the application of the “person skilled in the art” and “mechanical equivalence” principles in assessing obviousness and specifically notes – as a factor bearing on the ease of finding obviousness – that where the same inventor authored both the prior art and the subsequent patent application, the inferential leap required to establish obviousness may be more readily made. The declension’s significance is confined to the specific technical comparison undertaken (connection of installation bodies via a common bar element in a static mixer) and to the two procedural/methodological holdings described above; it does not purport to establish any broader or generally applicable test for inventive step beyond reaffirming existing principles under Sections 2(1)(j) and 2(1)(ja) of the Patents Act.

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