Corus UK Ltd v Qual-Chem Ltd

Corus, the defendants, appeal from a judgment and order of HHJ Fysh QC sitting in the Patents County Court, [2008] EWPCC 1. He held that Qual-Chem’s patent No. 2,363,635 was valid and infringed. After hearing Mr Thorley QC open the case for Corus we concluded that it was unnecessary to hear oral argument from Mr Wyand QC. He had of course already provided a skeleton argument which we found most helpful. We indicated the appeal would be dismissed. These are my reasons for so deciding.

Although Corus pleaded many more points originally, the Judge had to deal with what, by my count, were no less than 10 discrete points or sub-points. The taking of many points is often the mark of a party which does not feel it has a single “killer”. So it proved before the Judge who rejected all of them.

On appeal, Corus have restricted themselves to just two points: a single issue of non-infringement and an allegation that the patent is invalid pursuant to the provisions of s.72(1)(d) of the Patents Act 1977.

Neither side suggests that this case involves our having to decide any question of legal principle. For that reason there is no need to write this judgment as a self-standing document for a general readership. For the same reason it is not necessary to set out here matters which are uncontroversial, were dealt with by the Judge and can be referred to by cross-reference. This judgment is to be read in conjunction with his judgment which is available at www.bailii.org.

The patent was amended following grant. We are concerned with that amended patent which has what is known as a “C” specification. The “A” specification is the application as filed. The “B” specification (which does not matter for present purposes) is the patent as granted. The Judge describes the “C” specification uncontroversially at paragraphs [20-31].

Claim 1 of the patent was broken up into integers by the Judge as follows:

The Judge held that the addressee of the patent – “the person skilled in the art” – was “a person involved in process and technical management of a steel plant and, in particular, a person with hands on experience of primary and secondary steel making processes”. Mr Thorley QC for Corus accepted that.

The common general knowledge of such a person was summarised by the Judge in [12-19]. Reference may be made to those paragraphs for more detail but for present purposes it is sufficient to note the following:

This involved no question of legal principle and raised no controversy before us. The key provision is Art 123(2) of the European Patent Convention:

A European patent application or a European patent may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed.

The provisions of the UK Act are, typically I am afraid, in unnecessarily different and more convoluted language. Neither side suggested they had any different meaning from the Convention so there is no need to waste time going to them.

The authorities on added matter are well known and were recently summarised in this Court, in European Central Bank v Document Security Systems [2008] EWCA Civ 192 at [11-12] and Vector v Glatt [2007] EWCA Civ 805, [2008] RPC 10 at [3-8]. Since it is uncontroversial there is no point in reciting these passages here.

Mr Thorley also reminded us of what Neuberger LJ said in LG Philips v Tatung [2006] EWCA Civ 1774, [2007] RPC 21 at [28-34]. He faintly suggested that Aldous J, in Southco v Dzus [1990] RPC 587 at p. 616, in referring to a comparison of the inventions of the A specification and the patent was somehow posing a different requirement than that of added subject-matter. But it is clear he was not, as his well-established test in Bonzel v Intervention (quoted in the passages I have cited) shows. In the end, as I said in Richardson-Vicks Patent [1995] RPC 568 at 576, it comes to this:

.. the test of added matter is whether a skilled man would, upon looking at the amended specification, learn anything about the invention which he could not learn from the unamended specification.

So what we have to do is to ascertain what is disclosed explicitly and implicitly in the “A” specification. This must be done without hindsight, i.e. without knowing the result being sought. The same exercise must be performed on the “C” specification. We are looking to see whether there is an extension of subject matter.

Mr Thorley contended that the “A” specification is confined to the treatment of “molten iron” meaning strictly the material itself as opposed to the supernatant slag. He was prepared to accept that the specification did contemplate some treatment or effect on the slag, but, he submitted there was no disclosure of the treatment of slag alone.

There is no option at this point other than to go to the A specification to see whether this contention is made out. I set out most of the relevant passages, in an appendix to this judgment, labelling them for use in this subsequent discussion.

Mr Thorley’s primary contention was based on the premise that the term “molten iron” is used in contrast to the supernatant slag and that that was so throughout the specification. He submitted that passage B contained a definition of “iron” and so “molten” iron could only mean the material specified there. I do not so read the passage. It is a passage about the kinds of steels for which the process can be used and no more.

I say that because it is clear that in several other passages the expression “molten iron” in context must mean the “iron” with supernatant slag – the liquid as a whole. Passage C for instance speaks of the “surface of the molten iron”, and penetration below the surface “through slag”. So the surface must be that of the slag itself and the “molten iron” must here mean the iron with its slag. Again the language of A (also that of the proposed claim too) speaks of “impinging upon the molten iron”. That would be a very odd way of describing firing the additive through the slag to reach the iron below. The language of D, speaking of the “footprint” for the additive, is more naturally read as being the surface which the additive is sprayed at, i.e. the slag.

Going on, passage E clearly contemplates reaction between the additive and the slag. Mr Thorley so accepted, but suggested that it was only so contemplated where the tablets also went into the iron itself. I do not see why that is so.

Passage F, including “rather than descending into the liquid iron below”, could hardly be clearer. It plainly contemplates treatment of the slag alone. I confess I did not follow how Mr Thorley sought to get out of that. His skeleton argument suggests the passage is limited to “using a predetermined specific density alone” (his italics and emphasis). But it simply is not. And besides even if it were it would still be about treatment of slag alone.

Passage H describes the process being used for “killing slag on the surface.” That is inconsistent with Mr Thorley’s contention. Passage I is utterly conclusive. For it mentions the use of calcium carbonate – a material which it is conceded one would not want to put into the underlying iron and would only use to kill slag. And passage J clearly contemplates treatment of slag.

Thus I think the A specification clearly discloses the use of the process for the treatment of slag alone.

That does not quite deal with Mr Thorley’s argument. For he made a special point about passage G. He submitted that when read in the A specification the suggestion to use a pressure of 7 bar is for the treatment of iron in his strict sense, whereas when that is repeated in the C specification the teaching is to use that for slag alone. I reject that for several reasons. First I do not regard the passage in the A specification as being confined to treatment of the underlying iron. It is much more general than that. The very passage itself speaks of the “thermal currents encountered above the molten iron” which must mean in context above the slag. Secondly the point was never pleaded (I reject the suggestion that the generality of the pleading encompassed this specific point). And thirdly (not surprisingly) the point was not explored in the evidence. I would not allow it to be taken now if, contrary to my first reason, there might be something in it.

Finally on added matter I should mention Mr Thorley’s criticism of the judgment. He suggested that the Judge had dealt with added matter and loss of priority as though they involved the same legal test whereas they do not (for added matter “extends beyond the subject-matter”, for priority “supported by” the priority document). I will assume he is right, though I am not sure he is – the language of the EPC does not use the expression “supported by.” It would make no difference here. Although the Judge dealt with the subject under the heading “Loss of Priority and Added Matter” and referred to passages in the priority document, those passages are the same as in the A specification so far as I can see. Certainly Mr Thorley pointed to no passage in the priority document which the Judge used in his reasoning which was not also in the A specification.

Moreover the Judge did deal with added matter as a distinct matter under a separate heading, commencing with a correct citation of the principles from Bonzel and Richardson-Vicks. He concluded that “the teaching relating to slag killing … has always explicitly been present.” For the reasons I have given I think he was right as regards the A specification which is all that now matters.

So I would reject the added matter attack.

The only non-infringement point now taken relates to integer E of the claim, which I repeat here:

the conveying gas pressure being tailored with respect to the conveyed additive material to cause the conveyed additive material to penetrate into and remain in the slag

Mr Thorley contended that “being tailored” were words of limitation which could not be ignored (see Step v Emson [1993] RPC 513 at 522 per Hoffmann LJ). I agree with that. So what do they mean? Mr Thorley submitted that they meant that once all the other variables (nature and thickness of slag, nature and shape of additive and so on had been selected) the pressure had to be adjusted (tailored) so that additive was conveyed into and remained in the slag. You could only infringe if your apparatus had some pressure adjustment means.

He did not go so far as to submit that there should be a continuous adjustment means. If and insofar as the Judge had thought that was the contention below he had misunderstood it - though that was the suggestion of Corus’s expert. The pressure had to have been “adjusted” – that is what “tailored” meant.

He reinforced this suggestion by pointing to some evidence about the common general knowledge given under cross-examination by Dr Bommaraju, Qual-Chem’s expert witness. The effect of this was conditions are apt to vary significantly. Mr Thorley submitted that the skilled reader, knowing that, would expect the pressure to be variable so as to be able to cope with the varying conditions.

I reject Mr Thorley’s submission. The key thing in the integer – the very purpose of the method – is to get the additive in the slag. There is no need to read “tailored” as having such a limited meaning as suggested by Mr Thorley, or indeed the even more limited meaning suggested by Corus’ expert. The key question is “what the person skilled in the art would have understood the patentee to have been using the language of the claim to mean” see Kirin Amgen v TKT [2005] RPC 9 [30]-[35].

Given the known purpose I think the skilled reader would read the word “tailored” meaning “so arrived at” or “chosen” so as to have the desired effect. To carry out the method there are a variety of variables which must be adjusted in interdependence on others - one of these is the pressure. If that is correct for the rest of the variables then it is “tailored” within the meaning of the claim. Giving it that meaning is not ignoring it.

The conclusion is reinforced by the body of the specification. It uses “tailored” for other variables such as the gun and the briquettes of additive. In context the word clearly includes “selected so as to be suitable for”

Mr Thorley referred to what happened at the Corus’ works. The guns were supplied from the compressed air line of the standard plant supply. This was variable stated in the process description to be within a range of 3 to 6 bar – though according to the plant manager it “usually lies at approximately 4 bar” and “rarely goes above 5 bar.” That, submitted Mr Thorley, could not be regarded as “tailoring”, even though it in fact worked.

I do not see why not and every reason to see why. No one suggests that this sort of operation is a matter of precision. The variable nature of the pressure used at Corus does not mean that it was not selected so as work. It did and that is why it was chosen.

So I would reject the non-infringement point too.

Appendix – Passages from the “A” Specification

A “According to a first aspect of the present invention, there is provided a method of introducing at least one additive into molten iron in a steelmaking process, in which the additive in particulate solid form is conveyed pneumatically to impinge upon the molten iron and mix therewith ….” (2_1-7)

B “When the pneumatically conveyed stream is to substantially cover a surface of molten iron in a receptacle, the outlet is above, and preferably outwardly spaced from an outer edge of the receptacle. The term “iron” as used herein encompasses any predominantly ferrous metal or alloy (which may contain incidental ingredients or impurities) suitable for use in a steelmaking process. It specifically includes the material being poured from a converter vessel in the course of a steelmaking process.” (2_21-30)

C “When the stream including the additive is directed towards the surface of the molten iron in the receptacle, the additive is preferably conveyed to reach below the aforesaid surface, penetrating through slag or other covering thereon.” (4_6-12)

D “According to the invention, however, the “footprint” of the conveyed additive preferably covers the entire surface of the molten iron in the receptacle.” (4_22-24)

E “The additive may be in any suitable particulate form, such as tablets, pellets, briquettes or powder. The density and composition of such tablets, pellets, briquettes and the like may be tailored in order to penetrate to predetermined depths in the molten iron at a predetermined rate. This enables the additive to be tailored to perform specific reaction requirements at specific depths and times. For example, the specific density and composition of tablets introduced into molten iron may be selected to break down quickly when in the presence of hot slag, but to react with the specific chemical components in the molten iron which are targeted for neutralisation or alteration.” (5_12-29)

F The predetermined specific density of the particulate additive can ensure that the particles penetrate into, and remain in, the slag (rather than descending into the liquid iron below) but resist flaring off on the surface.” (5_25-28)

G “The delivery pressure and velocity of the conveying gas can therefore be tailored, depending upon the ‘sinkage’ requirements of the additive being delivered and the upward thermal currents encountered above the molten iron in the relevant process stage. Typically, the dispensing pressure of the conveying gas will preferably be substantially in the range of 7 bars plus or minus 20%. The discharge rate of dispensed material is preferably substantially in the range 0.5 to 15m³ per hour.” (6_9-17)

H “In some embodiments of the invention, it is preferred that the additive comprises a multiplicity of shaped elements (such as tablets, briquettes or the like), which preferably include aluminium when the additive is to be used for reheating steel during secondary steel making, or for “killing” slag on the surface of a steel ladle. Such shaped elements preferably comprise compressed divided material, which form individual self-supporting elements. (7_18-25)

I “Especially when such elements are used for killing slags, it may be beneficial to include calcium carbonate, such that when reaction takes place with the slag, carbon dioxide will be released, which will then gently bubble and effectively stir in the aluminium.” (7_27-31)

J “The shaped elements may additionally or alternatively include one or more non-aluminium materials, preferably arranged to have a conditioning influence upon molten iron or slag. For example, the shaped elements may include slag conditioning additives and/or ladle insulating powers.” (8_11-15)

I agree.

I also agree.