Cool interim order for ITW’s pre-conditioned air patent, but Competitor’s airport deals allowed to continue

In a patent infringement case between ITW GSE APS and others (“Plaintiffs”) and Dabico Airport Solutions Pvt. Ltd. and others (“Defendants”), the Delhi High Court disposed of an application seeking an interim injunction relating to pre-conditioned air units. The Court granted an injunction in favor of ITW GSE APS restraining Dabico from infringing ITW’s pre-conditioned air patent during the pendency of the suit.

ITW GSE APS, a prominent Danish affiliate of Illinois Tool Works Inc., filed the suit asserting that Dabico’s PCA units infringed upon its patented technology covered by Patent no. IN 330145. This patent encompasses a Pre-conditioned Air Unit (PCA) designed to provide conditioned air to aircraft on the ground, featuring variable frequency drivers (VFDs) controlled by a central controller. The central controller adjusts the cooling based on various parameters such as ambient temperature, humidity, and cabin temperature, ensuring optimized performance and energy efficiency.

The plaintiffs argued that their patented PCA unit had been widely recognized and installed at major airports worldwide, including in India at Bangalore and Mumbai. They contended that Dabico’s PCA units, which had won tenders at airports in Goa, Hyderabad, and Delhi, infringed upon their patent claims. To prove this, they submitted claim maps based on information of the Defendant’s product available in catalogues, manuals and tenders.

In response, Dabico raised several defenses. They claimed that ITW’s patent lacked inventive step and was not novel, and that ITW’s actions of filing 2 patents on the same invention amounted to double patenting. They argued that the invention disclosed in the patent was also disclosed in prior art references D2, D6, and D14. Additionally, they asserted that their PCA units were non-modular and therefore, they did not infringe upon ITW’s patent, which they characterized as modular.

After thorough analysis, the Court concluded that the defendants had not presented a credible challenge to the validity of ITW’s patent. As per the Court, the suit patent exhibited a clear inventive step over the prior art references, and the allegations of double patenting were unfounded. It found clear differences between prior arts D2, D6, and D14, and stated that hindsight mosaicing would not be permitted for inventive assessment.

Moreover, the Court stated that ITW’s patent related to the functional and electrical aspects of the PCA unit rather than its modularity. It observed that the defendants failed to not only provide evidence to support their claim of non-infringement but also failed to adequately disclose details about their PCA units.

Finally, the Court analyzed the claim mapping provided by ITW, which included detailed comparisons between the patented PCA unit and Dabico’s products based on operation manuals and tender documents. As per the Court, this evidence demonstrated that Dabico’s products incorporated the same essential features that formed part of ITW’s patent claims, giving rise to a prima facie case of infringement.

Based on its findings, the Court issued a preliminary injunction against Dabico, prohibiting future manufacturing, selling, promoting, and distributing of the infringing PCA units. Furthermore, the Court also asked Dabico to disclose its turnover from the sale of the infringing products within four weeks, under seal.

Claim Construction, Infringement, Inventive Step and Double Patenting

Relevant paras from the Court’s judgment  discussing principles relating to claim construction, infringement, inventive step assessment, and double patenting read as follows:

“83. For the purposes of claiming infringement, first the claims are to be constructed and, thereafter, the claims are to be compared with the defendants’ product.

84. For construction of claims, various judicial tests have been adopted to interpret the patent specifications and claims, inter alia the pith and marrow test, the test of purposive construction etc. This aspect will be adverted to a bit later.

85. As regards the second step of comparison, if substantive elements of claims can be found in the defendants’ product through direct comparison or other methods, the defendants’ product would be deemed to infringe the patent. Essentially, the defendant’s product has to be compared with the claims of the patent to establish infringement. For the purposes of comparison, trivial variations do not matter. The Court has to make an assessment that the defendant’s product is producing the same effect (reference be made to RX Prism Health Systems Private Limited v Canva Private Limited and Others, 2023 SCC Online Del 4186).

(i) Claim Construction

86. Let us first deal with the first issue of claim construction.

87. The rival contentions on claim construction hinge on the issue of modularity of the PCA units. On one hand, defendants submit that the claims ought not to be constructed in isolation from the specifications; and when constructed through the prism of the specifications, the claims of the suit patent import an essential element of modularity to the invention, and therefore, at the very threshold, there is no infringement, since the defendants’ product is non-modular. To this, plaintiffs’ counsel asserts that the claims have to be given their ordinary and plain meaning, and that “reading-in” a limitation into the claim through the specifications is impermissible. Plaintiffs contend that nowhere in the claims, read as they are, is there a claim of modularity, and the claims when read with the specifications are agnostic to the concept of non-modularity.

88. As per the plaintiff, the essential feature of the suit patent is the ability of the PCA unit to automatically adjust cooling performance, according to at least one of the conditions i.e. type of aircraft, ambient temperature, humidity, cabin temperature, outgoing temperature, and outgoing airflow from the PCA unit. This was achieved by driving the compressor through a VFD, and in turn controlling the various compressors with VFDs by a central controller.

89. A bare perusal of claim 1 of the suit patent shows that the claim is for a PCA unit comprising a housing, with a blower, and a plurality of refrigeration systems. Each of the refrigeration systems comprises at least one compressor, at least one condenser, at least one expansion valve, at least one evaporator, and at least one VFD, which in turn is controlled by a central controller.

90. In itself, claim 1 does not speak of modularity. Modularity essentially involves using a modular system, in that, sets of components can be attached or detached, without disturbing the other components. Importantly, the other patent granted to the plaintiffs, being IN ‘952, with the same priority date, seems to in fact specifically advert to modularity.

91. The suit patent, on the other hand, focuses on the aspect of the VFD attached to the compressor and the management of various VFD’s through a central controller. The comparative between claim no. 1 of the two patents is provided by plaintiff and extracted as under:

Claims of IN’ 145

1. 1. A preconditioned air unit (10) for supplying preconditioned air to an aircraft parked on the ground, the preconditioned air unit comprising:

a housing (12) accommodating a flow duct (20) with an air inlet (22) for ambient air and an air outlet (25) for connection to the parked aircraft;

a blower (30) connected with the flow duct (20) for generation of an air flow from the air inlet (22) toward the air outlet (25);

a plurality of refrigeration systems (36), wherein each refrigeration system comprises:

at least one compressor (38);

at least one condenser (40);

at least one expansion valve (42);

at least one evaporator (44) connected in a flow circuit containing a refrigerant, and wherein the at least one evaporator (44) interacts with the air flow in the flow duct (20);

and at least one variable frequency driver (46, 54, 56) for power supply of the at least one compressor (38); and

the housing (12) further accommodates a central controller (60) that is configured for controlling operation of the preconditioned air unit (10) including the variable frequency drivers (46, 54, 56) of the plurality of refrigeration systems (36), characterized in that:

the at least one variable frequency driver (46, 54, 56) has a controller that is configured for variation of the output frequency of the at least one variable frequency driver (46, 54, 56); and the central controller (60) is connected to at least one controller of the at least one variable frequency driver (46, 54, 56); wherein the central controller (60) automatically adjusts the cooling performed by the preconditioned air unit (10) to at least one of: the selected type of aircraft, the ambient temperature, the humidity, the cabin temperature, the outgoing temperature and the outgoing airflow from the preconditioned air unit (10).

Claims of IN’ 952

1. 1. A preconditioned air unit (10) for supplying preconditioned air to an aircraft parked on the ground, the preconditioned air unit comprising a main unit with a housing (12) accommodating a flow duct (20) with an air inlet (22) for ambient air and an air outlet (25) for connection to the parked aircraft, a blower (30) connected with the flow duct (20) for generation of an air flow from the air inlet (22) toward the air outlet (25); and a plurality of compartments (34), each of which is configured for accommodation of a self-contained cooling module (36) comprising:

at least one refrigeration system, each of which includes at least one compressor (38), at least one condenser (40), at least one expansion valve (42), and at least one evaporator (44) connected in a flow circuit containing a refrigerant, and wherein the at least one evaporator (44) interacts with the air flow duct (20); and

at least one variable frequency driver (46, 54, 56) for power supply of the at least one compressor (38); and

each compartment is configured so that the at least one evaporator (44) interacts with the air flow in the flow duct (20) when the self-contained cooling module (36) is installed in the compartment, and wherein at least one self-contained cooling module (36) is installed in the plurality of compartments (34).

92. Ex facie, it seems that while IN ‘952 focuses on the mechanical arrangement i.e. modularity, the suit patent relates to the electrical and functional aspects of a PCA unit. Prima facie this Court is agreeable with the plaintiff on this assessment.

…

99. Chisum on Patents categorically proscribes the importation of limitations from the general discussion, embodiments and examples in the specifications. In this regard, the following extract is relevant:

“[A] Reading In or Importing Structural and Functional Limitations Into a Claim. The first caveat is that it is improper to import (i.e. “read in”) a limitation from the specification’s general discussion, embodiments and examples. Further, “[g]eneral descriptive terms will ordinarily be given their full meaning; modifiers will not be added to broad terms standing alone. This caveat bars the “reading in” of functional or process limitations as well as structural ones. Thus, it has been held improper to read a limitation on how an apparatus was used into a claim to the apparatus. Or a limitation on how a claimed structure was manufactured. On the other hand, an express structural limitation on a claim may be properly defined by reference to functional characteristics.”

100. Terrell on the Law of Patents echoes the same principle when it comes to claim construction, and states that it is not legitimate to cut down or extend the clear meaning of the claim. In coming to this conclusion, reliance was placed on the decision in Glaverbel SA vs. British Coal Corp (supra) where the Court held that a patent is to be construed objectively, through the eyes of a skilled addressee. The Court also held that the whole document must be read together, the body of specifications with the claims. But if the claim is clear, the monopoly sought by the patentee cannot be extended or cut down by reference to the rest of the specifications and the subsequent conduct is not available to aid the interpretation of a written document.

101. These aspects have also been recognized by the Division Bench of this Court in Ace Technologies (supra), when it observes that patent rights are in respect of the claims and are broader than the preferred embodiments in the following paragraph:

“42. In our view, the said contentions are not destructive of the other. We agree with the contention that the embodiments cannot be read to expand the scope of the Claims. The question whether the appellants have raised a credible challenge to the Suit Patent is required to be considered in context of the Claims because the patent rights are in respect of the Claims and are broader than the preferred embodiments. However, the description of the Suit Patent and the preferred embodiments are relevant to interpret and understand the Claims.

43. In Bishwanath Prasad Radhey Shyam v. Hindustan Metal Industries (supra), the Supreme Court had observed as under:–

“43. As pointed out in Arnold v. Bradbury, [[1871] 6 Ch. App. 706] the proper way to construe a specification is not to read the claims first and then see what the full description of the invention is, but first to read the description of the invention, in order that the mind may be prepared for what it is, that the invention is to be claimed, for the patentee cannot claim more than he desires to patent. In Parkinson v. Simon, [(1894) 11 RPC 483] Lord Esher, M.R. enumerated that as far as possible the claims must be so construed as to give an effective meaning to each of them, but the specification and the claims must be looked at and construed together.”

44. The claims cannot be read in isolation. It is necessary that the same be read in the context of specifications and the description of the patent. There is no dispute that the specifications and description of the patent are necessary for interpreting and understanding the claims. However, the specifications cannot broaden the claim. As stated above, the monopoly that the Patents Act grants is in respect of the specific claims and not the preferred embodiments.”

102. A clear enunciation of the nuanced assessment required during claim construction is provided by the United States Court of Appeals (Federal Circuit) in Conmark Communications (supra) where it was stated as part of the discussion that: “we recognize that there is sometimes a fine line between reading a claim in light of the specification, and reading a limitation into the claim from the specification”.

103. The defendants attempt to distinguish these authorities and decisions, are unmerited. It was essentially asserted that a purposive construction of the claim must be adopted, and that such construction of the claim would result in interpreting the claimed term “plurality of refrigeration systems” to be modularly interpreted, as that is the only embodiment sufficiently disclosed and enabled in the specification, while the non-modular embodiment was not “enabled”. However, this argument may not be sustainable. As stated above, the claim along with the specifications, seem to focus on the application of the VFD to the compressor, the variable controlling factor, and the overall central controller. The plurality of refrigeration systems as claimed, does not in itself assert modularity and, therefore, the claims would have to be seen as granted and it would be improper to read a critical limitation into the claims. As noted above, the difference with IN ‘952 is also dispositive in this regard, where modularity has been specifically claimed.

104. In any case, defendants have been unable to present any evidence of the fact that their PCA unit is non-modular in nature. The only submission canvassed before the Court was that the suit for infringement was not filed in relation to plaintiffs’ patent IN ‘952 because defendants PCA unit was non-modular in nature. However, no prima facie evidence has been presented in this regard.

(ii) Invalidity of the Suit Patent and credible challenge

a) Lack of an inventive step

105. Having accepted prima facie, the plaintiffs’ position that the claims are ‘agnostic’ to modularity and focus only on the VFD plus central controller, the defendants primary challenge then, as categorically submitted, is that the suit patent ought to be revoked for being invalid due to lack of an inventive step and for being obvious in light of the prior art.

106. In this context, relying upon the decisions in Glaverbel S.A. vs. Dave Rose & Ors., 2010 SCC OnLine Del 308, and F. Hoffman – LA Roche Ltd. & Anr. vs. Cipla Ltd., 2009 (110) DRJ 452 (DB), and Sulphur Mills Limited vs. Shree Ram Agro India & Ors. 2024: DHC: 2154, defendants argue that if there exists a credible challenge to the validity of the suit patent, interim injunction cannot be granted in favour of the plaintiff.

107. Relying upon the decision in F. Hoffman – LA Roche (supra), another Division Bench of this Court in Natco Pharma vs. Novartis AG and Another, 2024 SCC OnLine Del 3064, recently expounded the law on this subject. According to the said decision, in order to raise a credible challenge to the validity of the suit patent, the defendant needs to merely show that the patent is vulnerable to being invalidated. Unless such credible challenge is made, the question as to validity of the suit patent is required to be determined at the stage of trial. Relevant observations in Natco Pharma (supra) are extracted below:

“43. Unless there is no real prospect of the defendant to succeed in its challenge and an appropriate application to allow the action is made prior to framing of issues, the questions as to the validity of the patent asserted, are required to be determined at the trial. However, at the stage of interim relief, the defendant has to establish its assertion that its defence is not insubstantial and sets out a credible challenge to the validity of the patent. The defendant is not required to establish that the patent is invalid, it has to merely show that the patent is vulnerable. If the challenge raised to the validity is substantial, the threshold standard for resisting an interim injunction in this regard – subject to other relevant considerations-would be met. In this context, it is relevant to refer to the decision of the Division Bench of this Court in F. Hoffmann-LA Roche Ltd. v. Cipla Ltd.7. In the said case, the Division Bench had rejected the contention that the defendant had a heavy burden to discharge and would have to establish a stronger prima facie case than the plaintiff. The Division Bench had also not accepted the contention that since there is a multi-level examination of opposition to the grant of patent, it ought to be accorded the highest weightage. The relevant extract of the said decision is set out below:

“53. The plea of the plaintiff that since there is a multilayered, multi-level examination of the opposition to the grant of patent it should accorded the highest weightage, is not entirely correct. The contention that there is a heavy burden on the defendant to discharge since it has to establish that it has a stronger prima facie case of the plaintiff is contra indicated of the decisions in the context of Section 13(4). Reference may be made to the decisions in Biswanath Prasad Radhey Shyam v. Hindustan Metal Industries, (1979) 2 SCC 511 : AIR 1982 SC 1444 : Supp (1) PTC 731 (SC), StandipackPvt. Ltd. v. Oswal Trading Co. Ltd., AIR 2000 Del 23 : (1999) 19 PTC 479 (Del), Bilcare Ltd. v. AmartaraPvt. Ltd., (2007) 34 PTC 419 (Del), Surendra Lal Mahendra v. Jain Glazers, 1980 SCC OnLine Del 219. In Beecham Group Ltd. v. Bristol Laboratories Pty Ltd., (1967-1968) 118 CLR 618 and Australian Broadcasting Corporation v. O’Neill, (2006) 229 ALR 457 it was held that the defendant alleging invalidity bears the onus of establishing that there is “a serious question” to be tried on that issue. In HexalAustralai Pty Ltd. v. Roche Therapeutics Inc., 66 IPR 325 it was held that where the validity of a patent is raised in interlocutory proceedings, “the onus lies on the party asserting invalidity to show that want of validity is a triable question.” In Abbot Laboratories v. Andrx Pharmaceuticals Inc. (decision dated 22nd June 2006 of the U.S. Court of Appeals for the Federal Circuit 05-1433) the Court of Appeals followed its earlier ruling in Helifix Ltd. v. Blok-Lok Ltd., 208 F.3d 1339 where it was held (at 1359):”In resisting a preliminary injunction, however, one need not make out a case of actual invalidity. Vulnerability is the issue at the preliminary injunction stage, while validity is the issue at trial. The showing of a substantial question as to invalidity thus requires less proof than the clear and convincing showing necessary to establish invalidity itself.”

(emphasis supplied)

In Erico Int’llCorprn v. VutecCorprn (U.S. Court of Appeals for the Federal Circuit, 2007-1168) it was held that the “defendant must put forth a substantial question of invalidity to show that the claims at issue are vulnerable.”

54. In the present case, the grant of a patent to the plaintiffs for Erlotinib Hydrochloride as a mixture of Polymorphs A and B will not ipso facto entitle them to an interim injunction if the defendant is able to satisfy the court that there is a serious question to be tried as to the validity of the patent. The use by the learned Single Judge of the expressions “strong credible challenge”, “arguable case” or that the defendants claim being not unfounded, cannot be termed as vague and inconsistent since they convey the same meaning in the context of the strength of the defendant’s challenge.

55. The question before this Court is when can it be said that the defendant has raised a credible challenge to the validity of a patent held by the plaintiff in an infringement action? During the course of the argument it was suggested by counsel that the challenge had to be both strong and credible. Also, the defendant resisting the grant of injunction by challenging the validity of the patent is at this stage required to show that the patent is “vulnerable” and that the challenge raises a “serious substantial question” and a triable issue. Without indulging in an exercise in semantics, the Court when faced with a prayer for grant of injunction and a corresponding plea of the defendant challenging the validity of the patent itself must enquire whether the defendant has raised a credible challenge. In other words, that would in the context of pharmaceutical products, invite scrutiny of the order granting patent in the light of Section 3(d) and the grounds set out in Section 64 of the Patents Act, 1970. At this stage of course the Court is not expected to examine the challenge in any great detail and arrive at a definite finding on the question of validity. That will have to await the trial. At the present stage of considering the grant of an interim injunction, the defendant has to show that the patent that has been granted is vulnerable to challenge.

Consequently, this Court rejects the contentions of the plaintiffs on this issue and affirms the impugned judgment of the learned Single Judge”

44. It is also relevant to refer to the decision of the learned Single Judge of this Court in Astrazeneca AB v. Intas Pharmaceuticals Ltd.In the said case, the learned Single Judge rejected the contention that since the suit patents were old, they should be presumed to be valid. The learned Single Judge did so for two reasons. First, the learned Single Judge found – much like in the present appeal where it is the stated case that ELT-O is covered under both IN’ 176 and the suit patent IN’ 161 – that there was an overlap in the genus patent and the species patent. And second, that the presumption of validity exists only till such time the patent is challenged and the challenge is credible. The relevant extract of the said decision is set out below:

“51. Furthermore, the argument advanced on behalf of the plaintiffs that since the suit patents are old and thus, should be presumed to be valid cannot be accepted for two reasons.

(i) First, there is a period of overlap between the genus patent i.e. IN 147 and the species patent i.e. IN 625. The defendants, in this case, chose to wait [in line with arguments advanced in their defence of the suit actions] till such time the validity period of the genus patent i.e. IN 147 expired.

(ii) Second, as indicated above, the scheme of the Act does not foreclose the right of the defendants in defence to an infringement action to question the validity of the patent. Section 107 of the Act, expressly confers a right on the defendants to raise, in defence, in an infringement suit, all those grounds on which the patent can be revoked under Section 64 of the very same Act. Therefore, the judgment in Bristol-Myers Squibb Company v. J.D. Joshi, 2015 SCC OnLine Del 10109, if read in context, would demonstrate that it has not emasculated the right of the defendant, as conferred under the Act, to challenge the validity of the patent. The presumption of validity exists only till such time the patent is challenged – a challenge which is credible and no further. In my opinion, if the plaintiffs’ argument was to be accepted, then, it would have to be held that the older the patent, the stronger the firewall. Such an interpretation, in my view, would be contrary to the plain words of the Statute.

45. The appeal against the said decision was dismissed by the Division Bench of this Court as being without any merit.

46. In the present case, the learned Single Judge held that even if a prima facie ground for revocation is made out, revocation is not automatic as the patent authority retains discretion not to revoke the patent if not absolutely necessary. And, the vulnerability to revocation must also be adjudged on the same standard. The learned Single Judge also concluded that this standard is therefore, high rather than low. It was further observed that the credible challenge occupies a higher pedestal than challenge, which is merely worthy of consideration. The learned Single Judge held that “When an infringer seeks to defend infringement on the ground that the patent he infringes is invalid, the onus, to prove such invalidity heavily lies on him. This standard has to be met, when applying the principle of “credibility””. The standard as articulated in the impugned judgment is in clear variance with the decision of the Division Bench of this court in F. Hoffmann-LA Roche Ltd. v. Cipla Ltd.7. In the said case, the Division Bench had expressly rejected the contention that the defendant has a heavy burden to discharge as it has to establish a stronger prima facie case. It is apparent that in the present case, the learned Single Judge has applied a higher standard for examining whether a credible challenge to the validity of a patent is made out, than as explained by the Division Bench. In effect, the learned Single Judge has read in a presumption as to the validity of the patent, where none exists. Obviously, a challenge to a patent, that is insubstantial, would be wholly insufficient to resist an order of interdiction. However, if a prima facie ground of revocation is made out, the threshold standard of credible challenge is met notwithstanding the discretion vested with the patent authority in regard to revocation of the patent. The fact that the patent authority may have the discretion not to revoke the patent despite a ground for the same being established, is not a relevant consideration for granting an interim injunction restraining the infringement of a patent on the ground that the defendant has not met the threshold standard of a credible challenge to the validity of the patent, if a prima facie ground for revoking the patent is made out.

47. If the defendant raises a substantial challenge, which merits a trial, the question whether an injunction ought to be granted would necessarily have to be determined on other considerations for grant of such injunctions including balance of convenience and irreparable harm.

108. In order to analyse whether there is a credible challenge to the validity of the suit patent, it is required to be seen whether the submission as to lack of inventive step merits any consideration in the facts of the case. Section 2(1) (ja) of the Act defines ‘inventive step’ as under:

“(ja) “inventive step” means 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.”

109. A Single Bench of this Court in Avery Dennison (supra), summarized the different approaches followed by Courts over the years to determine whether the suit patent lacks an inventive step. In order to analyse whether a credible challenge to the validity of the suit patent has been raised by the defendant, and whether the suit patent lacks an inventive step, reference may be made to the following paragraphs from Avery Dennison (supra):

“11. For determining inventive step or lack thereof, various approaches and tests have emerged over the years from decisions of courts/authorities as also from examination guidelines of patent offices from different jurisdictions. The same include:

1. Obvious to try approach:

• • • This approach involves an analysis of whether in view of the teachings/solutions proposed in the prior art, it was obvious to try and arrive at the subject invention.

2. Problem/solution approach:

• • • This approach considers whether in the light of the closest prior art and the objective technical problem, the solution claimed in the invention would be obvious to the skilled person. If the skilled person can decipher the solution being claimed, then the subject matter is held to be obvious.

• • • This test has been discussed by the Division Bench in F. Hoffmann-La Roche Ltd. v. Cipla Ltd., (2016) 65 PTC 1 (Del).

3. Could-Would Approach

• • • In this approach the question that is raised is whether there is any teaching in the prior art as a whole that would and not simply could have prompted a skilled person, with the knowledge of the objective technical problem, to either modify or adapt the closest prior art to arrive at the subject matter of the claims.

4. Teaching Suggestion Motivation (TSM test)

• • • This test originated in the USA as per which, if by the Teaching, Suggestion or Motivation from the prior art, an ordinary skilled person can modify the prior art reference or combine prior art references to arrive at the claimed invention, then the subject matter being claimed is obvious.
    • However, the application of this test ought not to be done in a narrow manner as held by the US Supreme Court in the case of KSR International v. Teleflex, 550 US 398 (2007).

15. The tests laid down in Windsurfing (supra) were again considered by the England and Wales Court of Appeals in Pozzoli Spa v. BDMO SA, [2006] EWHC 1398 (Ch) and modified by Jacob LJ as under:

“1. (a) Identify the notional “person skilled in the art”

(b) Identify the relevant common general knowledge of that person;

1. 1. 2. Identify the inventive concept of the claim in question or if that cannot readily done, construe it;
      3. Identify what, if any, differences exists between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;
      4. Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?”

16. The ld. Division Bench of this Court in F. Hoffmann-La Roche Ltd. (Supra) added a further step as elaborated below:

“Step No. 1 To identify an ordinary person skilled in the art, Step No. 2 To identify the inventive concept embodied in the patent, Step No. 3 To impute to a normal skilled but unimaginative ordinary person skilled in the art what was common general knowledge in the art at the priority date. Step No. 4 To identify the differences, if any, between the matter cited and the alleged invention and ascertain whether the differences are ordinary application of law or involve various different steps requiring multiple, theoretical and practical applications, Step No. 5 To decide whether those differences, viewed in the knowledge of alleged invention, constituted steps which would have been obvious to the ordinary person skilled in the art and rule out a hindside approach”

1. 1. 17. Further, this Court in Bristol-Myers Squibb Holdings (supra) has summarised some of the principles which can be used determine whether an invention is obvious or not. The said principles are:

“(i) A hindsight reconstruction by using the patent in question as a guide through the maze of prior art references in the right way so as to achieve the result of the claim in the suit, is required to be avoided.

(ii) The patent challenger must demonstrate the selection of a lead compound based on its promising useful properties and not a hindsight driven search for structurally similar compounds.

(iii) There should be no teachings away from the patent in question in the prior art.

(iv) Mere structural similarity cannot form the basis of selection of lead compound in a prior art and the structural similarity in the prior art document must give reason or motivation to make the claim composition.

(v) Though mosaic of prior art documents may be done in order to claim obviousness, however, in doing so, the party claiming obviousness must be able to demonstrate not only the prior art exists but how the person of ordinary skill in the art would have been led to combine the relevant components from the mosaic of prior art.

(vi) It has to be borne in mind, small changes in structures can have unpredictable pharmacological effects and thus, structural similarity alone is not sufficient to motivate to selection of the lead compound.

(vii) Though it would be tempting to put together a combination of prior arts but this requires a significant degree of hindsight, both in selection of relevant disclosures from these documents and also in disregarding the irrelevant or unhelpful teachings in them.”

20. This Court in the case of Agriboard International LLC. v. Deputy Controller of Patents & Designs [C.A.(COMM. IPD-PAT) 4/2022 dated 31st March, 2022] held that while rejecting an application for lack of inventive step, discussion on the prior art, the subject invention and manner in which the subject invention would be obvious to a person skilled in the art would be mandatory. Merely arriving at a bare conclusion that the subject invention lacks inventive step would be contrary to Section 2(1)(ja) of the Act itself, is insufficient. The relevant portion of the judgment reads as under:

“24. In the opinion of this Court, while rejecting an invention for lack of inventive step, the Controller has to consider three elements-

• • • • • the invention disclosed in the prior art, • the invention disclosed in the application under consideration, and • the manner in which subject invention would be obvious to a person skilled in the art.

25. Without a discussion on these three elements, arriving at a bare conclusion that the subject invention is lacking inventive step would not be permissible, unless it is a case where the same is absolutely clear. Section 2(1)(ja) of the Act defines ‘inventive step’ as under:

(ja) “inventive step” means 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.

26. Thus, the Controller has to analyse as to what is the existing knowledge and how the person skilled in the art would move from the existing knowledge to the subject invention, captured in the application under consideration. Without such an analysis, the rejection of the patent application under Section 2(1)(ja) of the Act would be contrary to the provision itself. The remaining prior arts which are cited by ld. Counsel having not been considered in the impugned order, the Court does not wish to render any opinion in this regard.”

110. In the said decision, the Court also reiterated, in para 32, that fundamental principles governing an analysis on inventive step include:

firstly, that the simplicity of the invention does not defeat an invention ; secondly, that the inventive step has to be assessed on the basis of the date of priority of the subject patent and not after the publication of the same i.e. it is not permissible to a do a hindsight analysis or an ex-post facto analysis.

111. It is within the above broad matrix that the Court will analyse whether there exists a credible challenge to the suit patent. Challenging the validity of the suit patent under Section 3(d) of the Patents Act, the defendants relied upon 20 prior art documents. Of these, special focus was laid on three prior art documents: US 4835977 (6/6/1989) [“D2”] priority arts WO/1986/000977 (13/02/1986) [“D6”], US7207183 (13/10/2005) [“D14”].

112. Before the prior arts are analysed, it is relevant to carve out the inventive concept in the suit patent. The inventive concept of the suit patent is that at least one variable frequency driver attached to a compressor in the refrigeration unit of the PCA, supervised by a controller that is configured for variation of the output frequency of at least one variable frequency driver. The central controller is connected to at least one controller of at least one variable frequency driver wherein the central controller automatically adjusts the cooling performed by the preconditioned air unit according to factors such as ambient temperature, humidity, cabin temperature, outgoing airflow and temperature from the PCA.

113. Let us now analyse and compare the three prior arts cited by defendants with the suit patent.

Prior Art D2 (US 4835977 (6/6/1989)

114. Defendants counsel drew attention to D2 and submitted that it also relates to an aircraft air-conditioning system and, more particularly to apparatus and method of cooling the passenger cabin of a parked aircraft. A perusal of the original and complete specification of D2 reflects that its scope and objective is completely different to that of the suit patent. The abstract for D2 clearly states that the invention relates to a method and apparatus for air-conditioning parked aircraft, in which air at a temperature below the freezing point of water is provided under pressure to the aircraft. D2 departs from conventional mechanization of air conditioning systems by supplying air cooled below the freezing point of water. The prior art merely discloses a PCA unit, of which there is no denial by the plaintiff that they were well known, and the plaintiff does not claim inventiveness in a PCA unit per se, but in the VFD controller and the central controller configuration, which this prior art does not possess or claim. Moreover, the prior art focuses on maintaining a constant low temperature and managing humidity through periodic defrost cycles and using heat exchangers. In contrast, in the suit patent, the central controller automatically adjusts cooling based on multiple parameters, with specific focus on variable frequency drivers for efficient energy management. Therefore, it is clear that the suit patent and D2 deal with different inventive concepts and D2 cannot be used to mount a challenge to the suit patent.

Prior Art D6 WO/1986/000977 (13/02/1986)

115. Insofar as prior art D6, WO/1986/000977 (13/02/1986), is concerned, it merely teaches about a “Modular Refrigeration System” and not a PCA unit. Moreover, it is not the plaintiffs’ case that modular refrigeration systems were unknown in the state of the art.

116. As per D6, the modular units work in master-slave setup such that one modular unit acts as a master unit, controlling operations of all other units. D6 does not disclose a VFD, and a central controller that automatically adjusts the cooling performed by a PCA unit. The defendants have failed to disclose the relationship between a mater-slave set up and the control operation of the suit patent.

117. According to the averments made in the written statement, prior art D6, involves a modular construction aimed at increasing the capacity of the refrigeration system resulting from changes in load criteria of the air – conditioning installation. In D6, in the event of a malfunction in one of the modules, that module may be shut down by the control circuits while permitting continued operation of the other modules. Counsel for defendants placed specific reliance on the following paragraphs relating to prior art D6:

“Depending on the fault, the defective module may be repaired in situ while the system is in operation, or the defective module may be remove [sic] from the assembly for repair, a spare module being incorporated in the assembly to replace the removed, defective module or the assembly being permitted to operate without a replacement”.

118. A bare perusal of the above paragraph reflects that the primary focus of prior art D6 is modularity. However, in the previous section on claim construction this aspect has been analysed, and the Court is prima facie of the opinion that the suit patent is neutral to the aspect of modularity. Furthermore, D6 prima facie is not a PCA unit and it does not have the inventive concept involved in the suit patent, in that it does not have any variable frequency driver that has a controller configured for variation of the output frequency of at least one variable frequency driver. This difference between D6 and the suit patent would not be an obvious step for a person skilled in the art.

119. Moreover, D6 was published on 13 th February, 1986, after a time gap of 23 years from the suit patent, and indicates that the patent granted cannot be defeated on ground of obviousness. In this regard, paragraph 36 of the decision in Avery Dennison (supra) is relevant and is produced as under:

“36. One of the sure tests in analysing the existence of inventive step would also be the time gap between the prior art document and the invention under consideration. If a long time has passed since the prior art was published and a simple change resulted in unpredictable advantages which no one had thought of for a long time, the Court would tilt in favour of holding that the invention is not obvious”.

(emphasis added)

Prior Art D14 (US 7207183)

120. Defendants have relied upon D14 as being the closest prior art. Notably, D14 prima facie appears to be a chiller system and not a PCA unit. In this regard, plaintiffs’ submission that mere use of known refrigeration components would not make the chiller system a prior art to PCA units finds favour with the Court. Indeed, as submitted by plaintiffs, if defendants’ approach is adopted, all innovations in the field of air- conditioning would be non-eligible for patents.

121. Furthermore, D14 does not disclose a central controller but a control panel that is able to control the operation of 1 refrigeration circuit, having 1 VFD controlling compressors in parallel. The inventive step of the suit patent, on the other hand, hinges in the ability of the central controller to control multiple refrigeration systems (each having 1 VFD controlling 1 controller) at the same time in a PCA unit.

122. Pertinently, as has been submitted by plaintiffs, D14 teaches about how a VSD may be used to achieve the same desired voltage and frequency of the corresponding motors based on a common instruction from the VSD. The objective of the suit patent, however, is for the central controller to ensure that all compressors are able to operate at different operating frequency, to ensure that each refrigeration circuit/system is operating at desired conditions. D14 clearly states that the drawback of using 1 VSD for each compressor would make the chiller system more expensive. Therefore, prior art D14 and the suit patent have prima facie differences which do not constitute an obvious step for a person skilled in the art. No challenge to the suit patent can be countenanced in light of prior art D14.

Finding on Lack of Inventive Step

123. A perusal of the prior arts brought into focus by the defendants, namely D2, D6 and D14 reflects that there is a clear improvement and categorical difference between the said prior arts and the invention in the suit patent. Also, these prior arts are used to combine different elements in order to somehow demonstrate lack of inventiveness. This is what is termed as mosaicing of unrelated documents which is not permissible in inventive step analysis, unless the documents are inter-linked or cross-referenced.

124. It is settled law that while mosaicing of prior arts may be permitted, the party claiming obviousness must be able to demonstrate that not only do the prior arts exist, but also how a person of ordinary skill in the art would have been led to combine the relevant components from the mosaic of prior arts. In this context, the decision in Prism Cement (supra), as relied upon by the plaintiff, is instructive. Justice Manmohan Singh (Retd.) made the following observation in para 32 of the said decision:

“32. The greater the number of documents which must be so combined to reach the invention, the more likely on the whole that there is an inventive step, but regard must be paid to the nature of features which are combined.”

125. In the present case, the defendants have failed to establish how, even upon mosaicing of the different prior arts cited, a person skilled in the art may be able to take obvious steps leading towards the inventive concept in the suit patent. Defendants have failed to substantiate their claim that the inventive concept in the suit patent would be obvious to a person skilled in the art. Therefore, at the interim stage, no case for invalidity on the ground of lack of inventive step has been made out by the defendants.

b. Double Patenting

126. Defendants counsel submitted that the suit patent should also be revoked under Section 64(1)(j) of the Patents Act, which deals with revocation of patents obtained on a false suggestion or representation. Essentially, it was argued that the plaintiffs engaged in misrepresentation by failing to disclose the suit patent to the Controller examining IN ‘952, considering both patents are substantially similar to each other.

127. This submission is belied by the fact that the First Examination Report for both, the suit patent and IN ‘952, was issued by the same Controller, Mr. Amit Singh, on the same date, that is 16 th October, 2017. Therefore, it cannot be presumed that the Indian Patent Office was unaware of the two inventions, or that the plaintiffs secured the suit patent by making a false suggestion or representation.

128. Having thus analysed defendants’ key submissions to establish that the suit patent is invalid (on the ground of lack of inventive step and double patenting), this Court is of the opinion that defendants have been unable to mount a credible challenge to the validity of the suit patent. The suit patent does not, at this stage, appear vulnerable to being invalidated on the above grounds.

(iii) Infringement of the Suit Patent

129. The next issue which needs to be examined of clam mapping in order to assess the plaintiffs claim for infringement.

130. This Court culled out the principles governing patent infringement in India in SNPC Machines (P) Ltd. v. Vishal Choudhary, 2024 SCC OnLine Del 1681. Relevant paragraphs of the same are extracted below:

35. The following principles can be culled out collectively from the aforenoted decisions, since all of them rely upon the same previous sources while articulating them from different perspectives:

A) Infringement is to be adjudged objectively and defendant’s intention may not be material to determine this question; the emphasis however has to be on mapping of ‘essential elements’.

B) Whether elements which are missing in the defendant’s products are so essential or substantial that the absence would entitle the plaintiff to an injunction.

C) Patent infringement analysis, comparison of elements of the suit patent’s claims is to be done with the elements/claims of the infringing products.

D) There can be a case of non-infringement where each and every component of patent specification is not found in the infringing products i.e. all elements of a claim may not entirely correspond with the infringing product, but it still can be a case of infringement.

E) It is the pith and marrow of the invention claimed that is required to be looked into. This test had been referred to in Clark v. Adie, [L.R.] 2 App. Cas. 315 [House of Lords].

F) Non-essential or trifling variations or additions in the product would not be germane, so long as substance of the invention is found to be copied.

G) Pure literal construction is not to be adopted, rather doctrine of purposive construction should be applied.

H) Doctrine of equivalents is to be examined and applied if the substituted element in the infringing product does the same work, in substantially the same way, to accomplish substantially the same result. The source of this doctrine traces its origin to an old decision in Winans v. Denmead, 15 How. 330, 14 L.Ed. 717 which was cited with approval in Graver Tank and Manufacturing Co. v. Linde Air Products Co., 339 US 605 (1950) (Supreme Court of United States).

I) The essential feature in an infringing article or process are of no account. If the infringing goods are made with the same object in view, which is attained by the patented product, then a minor variation does not mean that there is no piracy. Some trifling or unessential variation has to be ignored. This principle was cited by the Division Bench of this Court in Raj Prakash v. Mangat Ram, ILR (1977) 2 Del 412.

J) While product v. product comparison shall not to be determinative of infringement as opposed to the granted claim v. product comparison, an essential comparison between the products of the plaintiffs and the defendants may be necessary.

K) The triple identity test is important – focusing on function, way the elements serve the function and the result obtained is suitable for analyzing mechanical device (cited in Warner-Jenkinson Co. Inc. v. Hilton Davis Chemical Co., 520 US 17 (1997) (Supreme Court of United States).

131. It is within this legal matrix that the Court will now analyse the claim mapping submitted by plaintiffs.

A. Claim Mapping

132. It is noted that plaintiff has relied on certain documents as noted above to assert their claim mapping, since defendants have not provided any specification of the product, and the Court has rejected plaintiffs’ application for appointment of Local Commissioner to inspect defendants PCA unit by judgment dated 1 st November, 2023. By judgment dated 01 st November, 2023, this Court had noted the submissions of defendant’s counsel that they stood by specifications and features of the defendants PCA unit as contained in the following documents:

(i) Two of the documents i.e. the brochure of the defendants PCA units when defendant nos. 1 to 3 used to trade under the brand Cavotec, and the brochure and data sheet of defendant no.4 who manufactured the Cavotec products have been filed on 04 th September, 2023.

(ii) Three other documents, i.e. the Operation, Maintenance and Troubleshooting Manual for PCA unit model PDX 45 IS and for PDX 60 IS of the defendant as well as the tender documents (RFP), released by the airport of Goa, delineating the specifications of the PCA unit required, where defendants bid was successful, were filed as confidential documents on 05 th September 2023. These documents were filed as confidential documents vide I.A No. 17220/2023 by plaintiff on the basis that these documents had been supplied by the defendants as part of their communication who assert that they must be kept confidential as they contain third party information.

133. Plaintiffs’ counsel in the submissions through the presentation adverted to the Operation Manual for PDX 60IS Model, filed as confidential documents to show that the various features of the suit patent map clearly to the defendants’ product.

134. Since the documents are being placed confidentially before the Court, relevant extracts from the said document, Operation Manuals, are not being adverted to. The Court has examined the same and tabulates the various features of the suit patent claim that map with relevant aspects of the defendant’s equipment as described in the Operation Manual.

Plaintiffs claim

1. 1. A preconditioned air unit (10) for supplying preconditioned air to an aircraft parked on the ground, the preconditioned air unit comprising:

a housing (12) accommodating a flow duct (20) with an air inlet (22) for ambient air and an air outlet (25) for connection to the parked aircraft;

a blower (30) connected with the flow duct (20) for generation of an air flow from the air inlet (22) toward the air outlet (25);

a plurality of refrigeration systems (36), wherein each refrigeration system comprises:

at least one compressor (38);

at least one condenser (40);

at least one expansion valve (42);

at least one evaporator (44) connected in a flow circuit containing a refrigerant, and wherein the at least one evaporator (44) interacts with the air flow in the flow duct (20); and

at least one variable frequency driver (46, 54, 56) for power supply of the at least one compressor (38); and

the housing (12) further accommodates a central controller (60) that is configured for controlling operation of the preconditioned air unit (10) including the variable frequency drivers (46, 54, 56) of the plurality of refrigeration systems (36), characterized in that:

the at least one variable frequency driver (46, 54, 56) has a controller that is configured for variation of the output frequency of the at least one variable frequency driver (46, 54, 56); and the central controller (60) is connected to at least one controller of the at least one variable frequency driver (46, 54, 56); wherein the central controller (60) automatically adjusts the cooling performed by the preconditioned air unit (10) to at least one of: the selected type of aircraft, the ambient temperature, the humidity, the cabin temperature, the outgoing temperature and the outgoing airflow from the preconditioned air unit (10).

Features of the defendants’ product

1.1 Extracts from the Manual categorically provide that the equipment is a PCA unit supplying preconditioned air to the aircraft mounted on a passenger boarding bridge.

1.2 The diagram from the diagrammatic representation from the Operating Manual shows that the defendants’ equipment is also in housing with air inlet and outlet to the parked area.

1.3 The diagram of the defendants’ shows the existence of a blower connected with the duct going to the outlet.

1.4 The diagram reference figure 1 Operating Manual does show a plurality of refrigeration systems where refrigeration system comprises one compressor, condenser, one expansion valve, evaporator in a flow circuit containing refrigerant where the evaporator interacts with air flow in the duct. Most importantly, it also shows that the compressor is connected to a variable frequency driver

1.5 The extracts from the Operating Manual describing the equipment, the cooling mode, unit control system, and the controller in Sections 1.1.4, 1.2.1, 1.2.4 and 1.2.4.1 show the presence of the controller incorporating various valves pressures and temperature sensors which coordinates the refrigeration circuit.

1.6 Section 1.2.4.2 of Operating Manual which provides for a VFD states that the compressor VFD controls and protects the compressor and controls the compressor capacity based on the load requirement for maintaining the output air temperature.

1.7 Section 1.2.1 of the Operating Manual describes the cooling mode of the defendants’ equipment categorically and states that each refrigeration circuit operates independently except for the coordinating effect of the control. Automatic controls determine how many circuits should operate and at what level depending upon input from the ambient and outlet air temperature sensors.

1.8 The above element is already referenced above in relation to VFD in Section 1.2.4.2 and cooling mode in Section 1.2.1 and Section 1.2.4.

135. These various features were also mapped with the RFP of the Goa airport. It is but obvious that defendants’ product would have complied with the RFP since they won the tender. The relevant specification of the RFP to which the defendants’ product would have mandatorily complied would be as under: a PCA system, contained in a housing, with a blower, multiple refrigeration units, with evaporators, compressors, condensers, expansion valves, compressors having individual VFDs, a central controller, which would supervise and diagnose internal and external faults and control all the VFDs.

136. It is evident at least prima facie that the specifications of the defendant’s product as evident through the Operation Manual for PDX 60IS Model and the Goa tender does map to the suit patent claims. More importantly, since the defendants have chosen not to provide any other information and restricted their non-infringement argument during submissions, to the claim of non-modularity, there is no real rebuttal on the issue of mapping. The Court is therefore persuaded, at least prima facie, to accept the claim mapping submitted by the plaintiffs.

137. The plaintiffs’ argument that defendants’ non-infringement defense was contrary to Rule 3B (vi) of Delhi High Court Rules Governing Patent Suits 2022, as it obligated the defendant to describe the productive technology used by the defendant to justify its defense of non-infringement, is possibly merited in these circumstances. As nothing else has been provided by defendants to side step or rebut the specific mapping claims; this Court is inclined to accept them prima facie at this stage, however, subject to the final adjudication post the trial.

I. RELIEF

138. In view of the above, the Court is of the opinion that plaintiffs have made out a prima facie case for interim injunction, and the grounds stated for irreparable harm and balance of convenience are also in favour of plaintiffs. Considering that the defendants have already won certain tenders with airports in India, the same will not be displaced, since it may effect third party rights and may also cause loss to the State Exchequer. However, the interim injunction as under will operate for the future:

a) The defendants, and all tholl be restrained from manufacturing, selling, promoting, distributing, dealing in any manner with the PCA unit bearing model number PDX 60IS or any other product i.e. a Pre-conditioned Air Unit (PCA) [for the purposes of aircraft air-conditioning while on the ground], which infringes plaintiffs registered patent no. IN 330145.

b) The defendants shall file an affidavit disclosing their turnover from the existing deployment of the model number PDX 60IS or any other product i.e. a Pre-conditioned Air Unit (PCA) [for the purposes of aircraft air-conditioning while on the ground], which infringes plaintiffs registered patent no. IN 330145, within a period of 4 weeks in a sealed cover.”

Citation: ITW GSE APS v. Dabico Airport Solutions Pvt. Ltd., CS(COMM) 628/2023 (H.C. Del. July 4, 2024). Available at: http://indiankanoon.org/doc/13832108/. Visited on: 16/07/2024.

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