Inland Steel Company v the Broken Hill Proprietary Company Limited

[1992] APO 63

official notice

decision of a delegate of the commissioner of patents

Application        :   No. 582721 in the name of INLAND STEEL
  COMPANY

Title             :   Controlling Uniformity of Alloy Content
  in Continuously Cast Steel

Action : Opposition under s.59 by THE BROKEN HILL
  PROPRIETARY LIMITED

Decision           :   Issued            .  Opposition
  dismissed on all grounds

patents act 1990

decision of a delegate of the commissioner of patents

Re:Patent Application No. 582721 by INLAND STEEL COMPANY and

opposition by THE BROKEN HILL PROPRIETARY COMPANY LIMITED

under Section 59 of the Patents Act 1952

background

Patent application 582721 by Inland Steel Company (Inland) was advertised accepted on 6 April 1989. On 6 July 1989 The Broken Hill Proprietary Company Limited (BHP) lodged a notice of opposition to the application under sec 59 of the Patents Act 1952. Evidence in support of the opposition was served on 25 February 1991 after BHP had obtained a number of unopposed extensions of time. After itself obtaining unopposed extensions of time, Inland advised the Office that it did not propose to lodge evidence in answer.

A hearing to determine the opposition was held in Melbourne on 13 August 1992.  Inland was represented by Ms Ann Slater, assisted by Mr Peter Heathcote, patent attorneys with Shelston Waters, and BHP was represented by Mr Greg Munt, patent attorney with Griffith Hack & Co.

THE SPECIFICATION

The specification states that the invention relates generally to methods for continuously casting steel, and more particularly to such methods wherein the steel contains at least one alloying ingredient.

In one method of producing continuously cast steel, molten steel is introduced from a ladle into an intermediate container known as a tundish and then flowed through tundish exit nozzles into a continuous casting mold.  Alloying ingredients such as lead and bismuth are added to the molten steel entering the tundish.  Not all the alloying ingredient added to the molten steel is recovered and, accordingly, more alloying ingredient must be added to the molten steel than that which is desired in the final solidified steel.

There are different stages and conditions occurring in the tundish during the casting operation.  For example, the step of introducing the steel into the tundish comprises an initial stage, during which the the tundish is being filled from a relatively empty condition, and a subsequent stage during which the tundish is relatively full.  The mass flow rate of the molten steel during the initial stage is greater than the mass flow rate of the molten steel during the subsequent stage because it is desirable to fill the tundish as quickly as possible, and so the ladle nozzle, through which molten steel is flowed from the ladle to the tundish, is typically fully opened during the initial stage of the steel-introducing step.  There are other process conditions or parameters involved in the continuous casting operation, and these include the temperature of the molten steel, the mixing energy to which the molten steel is subjected in the tundish, the residence time of the molten steel within the tundish, and the like.

It is desirable that the concentration of the alloying ingredient be substantially uniform throughout the cast, particularly where the alloying ingredient has a relatively low solubility in molten steel and has a density greater than molten steel, as for example in the case of lead and bismuth.

The specification then indicates that the invention seeks to provide a procedure whereby such uniform concentration may be produced.  The solution to achieving this result lies in the discovery that the recovery for the alloying ingredient in the tundish can vary with changes in the stages of the steel-introducing step and with changes in the process conditions or parameters during the casting operation. 

Thus, according to the invention, both the expected recovery (R) for the alloying ingredient in the tundish, and the mass flow rate (Fs) at which the molten steel is introduced into the tundish, are determined.  In addition, the mass flow rate (Fa) at which the alloying ingredient is added to the tundish is controlled so as to maintain, in accordance with the following formula, a substantially uniform concentration (Ca) of the alloying ingredient in the steel throughout the cast:
Ca = Fa x R/Fs.

Further in accordance with the invention, (Fa) is adjusted at various times throughout the casting operation to compensate for changes in (Fs) and (R) which occur and, as a result, the concentration (Ca) of the alloying ingredient is controlled so that variations thereof are no greater than +/- 9%, and preferably do not exceed +/- 5%, throughout the cast.

The specification proceeds to explain that the expected recovery (R) for the alloying ingredient in the tundish, for each of the several stages and conditions occurring during the casting operation, can be determined on the basis of previous casts.  This is accomplished by monitoring the amount of alloying ingredient added during the several stages and conditions occurring in each of a number of previous casts and chemically analysing the particular portions of the solidified steel which were processed during the respective stages and conditions in those previous casts.

The specification further explains that it is possible to determine the mass flow rate (Fs) at which the molten steel is introduced into the tundish throughout the casting operation by continuously monitoring the weight of the ladle from which the molten steel is introduced into the tundish and then calculating the mass flow rate from the change in ladle weight.

The specification ends with sixteen claims, of which claim 1 reads as follows:

"1. In a method for producing continuously cast steel having
    at least one alloying ingredient, wherein said method
    comprises the steps of introducing molten steel into a
    tundish, flowing said molten steel from daid (sic) tundish
    into a continuous casting mold, and adding said alloying
    ingredient to the molten steel entering said tundish, and
    wherein there are several stages and conditions occurring
    during the casting operation, a procedure for producing
    a substantially uniform concentration, throughout the
    casting operation, of said alloying ingredient, said
    procedure comprising the steps of:

determining in advance, on the basis of previous
     casting operations, the expected recovery (R) for said
     alloying ingredient in said tundish, for each of the
     several stages and conditions occurring during the
     casting operations;

determining the mass flow rate (Fs) at which said
     molten steel is introduced into said tundish,
     throughout the casting operation;

and controlling the mass flow rate (Fa) at which said
     alloying ingredient is added to said tundish, so as to
     maintain, in accordance with the following formula, a
     substantially uniform concentration (Ca) of said
     alloying ingredient in said steel throughout said
     cast:
         Ca = (Fa x R)/Rs:

said controlling step comprising adjusting said mass
     flow rate (Fa) at various times throughout said casting
     operation to compensate for changes in (Fs) and (R)
     occurring during the casting operation, whereby said
     concentration (Ca) varies no more than +/- 9%
     throughout said casting operation."

THE EVIDENCE

The evidence in support of the opposition consists of a statutory declaration by David Lyle Webster, and statutory declarations by Gary John Anderson, John Marshall Burgess and Neil Adrian Molloy  accompanied by various exhibits.  As indicated above, no evidence in answer was lodged. I will discuss the relevant parts of the supporting evidence where appropriate in my decision.

DECISION

The notice of opposition lists all grounds available under sub-sec 59(1).  At the hearing BHP indicated that it wished to pursue only the grounds of obviousness, lack of novelty and non-compliance with sec 40.

Obviousness

The question of obviousness involves asking the question whether the invention would have been obvious to a non-inventive skilled worker in the field equipped with the common general knowledge as at the priority date (see Wellcome Foundation Limited v VR Laboratories (Aust) Pty Ltd (1982) RPC 343). Thus a consideration of the question of obviousness must be made against the background of the common general knowledge in the art in Australia. Guidance as to what constitutes such knowledge may be found in Minnesota Mining and Manufacturing Co v Beirersdorf (Australia) Ltd (1980) 144 CLR 253.

Mr Munt submitted that significant weight should be placed on the statements made by the declarants for BHP as to the state of the common general knowledge in view of their expertise in the field of the invention and BHP's predominance in that field in Australia.  He also pointed out that Inland had not lodged any evidence which contested the evidence in support.  While acknowledging BHP's standing in the steel making industry in Australia, Ms Slater argued that none of its declarants is a skilled but non-inventive worker in the relevant field as required by the case law on obviousness and, consequently, their evidence is of little probative value.

Mr Webster deposes that he is a graduate in metallurgy (Honours level) from Newcastle University.  He joined BHP in January 1970, and in the period 1979 to August 1985 was responsible for developments in certain steelmaking practices.  Since then he has had quite a deal of experience in relation to bloom caster commissioning and technology development, and at the time of making his declaration was responsible for all aspects of bloom caster operations and maintenance.

Mr Anderson deposes that he joined BHP during 1974 and since then has acquired considerable practical knowledge in the field of steel casting.  In addition he completed a technical course in metallurgy in 1978.  Mr Burgess deposes that he has gained qualifications in chemical engineering up to the Ph.D. level (Edinburgh) and, inter alia, is a Fellow Member of the Australian Institute of Mining and Metallurgy, and a Member of the Iron and Steel Society.  At the time of making his declaration he held managerial responsibility for process metallurgy research with BHP, having served as a research officer in BHP's central research laboratories for a number of years.  He has also served as a member of various National Advisory Committees.

Mr Molloy deposes that he is an engineering graduate from the University of Queensland, majoring in metallurgy, and subsequently lectured for several decades in the field of process metallurgy of iron and steelmaking.  His involvement with  research into steelmaking operations dates back to 1966, and during the 1970's publications in this field were usually made in collaboration with BHP staff.  From 1984 work related to the BHP bloom caster was carried out in Mr Molloy's flow laboratory.  Since retiring he has maintained an association with research being performed at the University of Newcastle under BHP sponsorship.  His other direct connection in this field is as a co-developer of a computer package for residence time analysis of tundish type flows.

Taking account of the information placed before me on this matter, and the partly theoretical nature of the invention, I consider that the non-inventive skilled worker in the present circumstances is not the actual worker on the steel production line, but instead is a worker having "intermediate" technical skills as per Graham J in American Cyanamid Company v Ethicon Limited [1979] RPC 215 at page 246. I therefore accept Mr Munt's submission that Messrs Webster and Anderson are appropriately skilled workers in the field of the invention. However I am inclined to agree with Ms Slater that Messrs Burgess and Molloy are over-qualified for the role of non-inventive skilled worker in view of their specialist backgrounds (British Celanese Ltd v Courtaulds Ltd (1933) 50 RPC 63).

I now have to take into consideration what has been established by the evidence as common general knowledge in the field of the invention at the priority date of the claims.  The relevant parts of Mr Webster's declaration in this regard read as follows:

"7. The patent application describes (see the paragraph bridging pages 2 and 3 in particular) that the invention the subject of the patent application is based on the discovery that the recovery for an alloying ingredient in a tundish is not constant during a casting operation and, in particular, varies with the stages of the casting operation.  As a consequence, the patent application proposes as an invention:

(a)  the determination in advance, on the basis of
     previous casts carried out under the same
     conditions, of the expected recovery for an
     alloying ingredient for each stage in a
     casting operation; and
(b)  the calculation of the rate of addition of
     the alloying ingredient during each stage,
     having regard to the expected recovery and
     the flow rate of steel into the tundish in
     each stage, to provide a substantially
     uniform concentration of the alloying
     ingredient throughout the casting operation.

8. Basically, before the priority date of the patent application I would have expected that the recovery for an alloying ingredient added to molten steel entering a tundish during the initial stage of a casting operation in which there are essentially unsteady state conditions would be different to the recovery for the alloying ingredient added to molten steel entering the tundish during the subsequent stage of the casting operation in which there are essentially steady state conditions.  As a consequence, had I been given the task of controlling the addition of an alloying ingredient to molten steel during continuous casting, as a matter of routine, I would have checked whether in fact the recovery of the alloying ingredient in each stage is different.  Furthermore, had I determined, as expected, a difference in the recovery in each stage, as a matter of routine, I would have used a different rate of addition of the alloying ingredient as a proportion of the flow rate of steel in each stage to compensate for the difference in the recovery in order to provide a substantially uniform concentration of the alloying ingredient throughout the casting operation.  It was well known to me before the priority date of the patent application that the most practical approach for determining the expected recovery of an alloying ingredient under a given set of casting conditions is to obtain data on the recovery of the alloying ingredient in previous work carried out under the given set of casting conditions.  In the circumstances, the invention the subject of the patent application and summarised in clause 7 above proposes precisely the routine approach that I would have adopted before the priority date of the patent application had I been given the task of controlling the addition of an alloying ingredient to molten steel during a continuous casting operation of the alloying ingredient in the cast product."

These statements are corroborated by Mr Anderson.  However it seems to me from comments made by Mr Webster such as "I would have expected ...", "... had I been given the task ..." and "... had I determined ..." that his evidence is an example of the ex post facto dissection of an invention which has been criticised in many courts (see Palmer v Dunlop Perdriau Rubber Company Limited (1937) 59 CLR 30, British Acoustic Films Ltd v Nettlefold Productions (1936) 53 RPC 221, and British Westinghouse Electric and Manufacturing Co Ltd v Braulik (1910) 27 RPC 209). Quoting from Palmer v Dunlop (supra):

"It is frequently possible to take, as it were, a patent to pieces, and then, beginning with one piece, to show how, in order to obtain one result, step A must be taken; in order to obtain another particular result, step B must be taken - and so on until one has the whole combination for which inventive quality is claimed.  If the analysis is taken into sufficient detail, every single step in the development of an invention, taken separately, can be shown to be obvious. ......

But, in the present case, the evidence of the expert witnesses for the defendant is really a reconstruction of an inventive process step by step, each step, when it is known that it must be taken and that it must be taken in a certain direction, being obvious enough in itself."

The manner in which Mr Webster has prefaced his evidence also suggests that he has never actually been given the task of controlling the addition of an alloying ingredient to molten steel during a continuous casting operation to ensure a uniform concentration of the alloying ingredient in the cast product.  In any event, the extent of common general knowledge established by Mr Webster's evidence would at best appear to be that it was known to determine the expected recovery of an alloying ingredient under a given set of casting conditions by obtaining data on the recovery of the alloying ingredient in previous casts carried out under the same given set of conditions. 

However, even assuming this to be the case, I note that such determination  constitutes one step only of the procedure as claimed in claim 1.  As pointed out by Ms Slater, where a combination patent is involved, it is the combination which must be shown to be known, as distinct from the separate integers which make up that combination (Minnesota Mining and Manufacturing v Beiersdorf (supra) and Nicaro Holdings Pty Ltd v Martin Engineering (1990) 91 ALR 513). In the present case the evidence before me fails to establish that it would have been obvious for a so-called non-inventive skilled worker to use the known means of determining the expected recovery of an alloying ingredient under a given set of casting conditions in conjuntion with the other procedural steps specified by the claimed invention so as to maintain a substantially uniform concentration of the alloying ingredient throughout a steel casting operation (Sharp & Dohme Inc v Boots Pure Drug Company Ltd 45 RPC 153).

On the basis of the foregoing, I find that BHP has provided insufficient evidence to establish the ground of obviousness.

My findings that the claimed invention is non-obvious would stand even if I took the Burgess and Molloy declarations into account.  Mr Burgess simply states that he agrees with the statements made by Mr Webster regarding the nature of the invention and the alleged extent of common general knowledge, and I consider Mr Molloy's evidence to be open to criticism for reasons similar to those already given in relation to the evidence of Mr Webster.

Furthermore, although the conservation of mass is a well established conservation principle which Mr Molloy asserts has been utilised to determine the efficiency of alloy recovery in liquid steel systems, nowhere in his evidence does Mr Molloy establish that the use of this principle in accordance with the claimed invention would be obvious to a non-inventive skilled worker.  In fact the statement made by Mr Molloy in paragraph 6(a):

"(I understand this to be the routine utilisation of historical data to derive an empirical prediction of the recovery performance of the steelcasting process...")

suggests that he does not possess sufficient technical expertise to be able to state whether the application of this principle to determine in advance the expected recovery of an alloying ingredient for each stage in a casting operation based on previous casts under the same conditions is common general knowledge in the field of the invention.

Mr Molloy also fails to establish whether the textbooks identified in paragraph 7 were available in Australia before the priority date and, if so, whether they have become common general knowledge.  It should be noted here that the fact that these books may have been available on a library shelf or in circulation does not itself mean that they can be regarded as common general knowledge (Riekie & Anor v M J McGrath Pty Ltd & Anor (1986) AIPC 90-311 and British Acoustic Films v Nettlefold (supra)). 

Novelty

This ground was argued on the basis of the declaratory evidence lodged in support of the opposition, rather than direct evidence of prior documentary publication or prior use.

The test for novelty is whether an alleged anticipation is the same in substance as the claim in suit so that the alleged anticipation would, if the patent were valid, constitute an infringement (Nicaro Holdings v Martin Engineering (supra) and R D Werner & Co Inc v Bailey Aluminium Products Pty Ltd 85 ALR 679). This test is commonly referred to as the reverse infringement test which was formulated by Aickin J in Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228 at page 235.
I have already found above that the evidence in support at most establishes the prior existence of only one of the integers of the claimed invention.  I therefore consider that the claimed invention differs from the prior art as established by the evidence in matters which clearly make a substantial contribution to its performance, so that the differences amount to more than mere workshop variations or mechanical equivalents.  As a result the prior art in question would not constitute an infringement of the claimed invention and the reverse infringement test is not satisfied.

Mr Munt also argued that the claimed invention comes within the concept of a "working direction" and as a consequence is not directed to patentable subject matter.  From the evidence before me it seems that the production of continuous cast steel which incorporates at least one alloying ingredient is itself a known process.  However, as I have found above, the presently defined procedure for producing a substantially uniform concentration of the alloying ingredient(s) throughout that known process is novel and non-obvious.  The claimed invention therefore does not simply reside in operating instructions for the working of a known process to achieve an old result more efficiently (Quigley Co Inc's Application [1977] FSR 373) and, accordingly, I do not find Mr Munt's argument in this matter to be well-founded.

Section 40

Mr Munt submitted that the specification does not comply with sec 40 because it is directed to a mere discovery or bare principle, as opposed to a patentable invention.  The issue of "discovery" or "principle" (together with the issue of "working directions" considered above) is more appropriate to the opposition ground of manner of manufacture.

In any case, I do not agree with Mr Munt's submissions in this matter.  On page 2 the specification refers to the discovery that the recovery for the alloying ingredient in the tundish can vary with changes in the various stages of introducing the molten steel into the tundish, and with changes in the process conditions or parameters during the casting operation.  However it is evident from a reading of the ensuing disclosure that the subject matter put forward by the specification as the invention does not simply reside in this discovery.  The invention instead contemplates a practical application of the discovery to determine in advance the expected recovery for the alloying ingredient in the tundish and, as pointed out by Ms Slater, such determination is only part of the combination of integers which make up the invention. 

Finally, I observe that claim 1 contains an error at line 26.  According to the body of the specification, the mass flow rate at which the alloying ingredient is added to the tundish is controlled so as to maintain a substantially uniform concentration of the alloying ingredient in the steel throughout the cast in accordance with a certain formula.  This formula has the mass flow rate at which the molten steel is introduced into the tundish (Fs) as its denominator.  On the other hand, the formula defined by claim 1 at line 26 has a denominator "Rs" and omits any reference to "Fs".  However I do not believe that this error leads to ambiguity when considered in the context of the entire specification (Decor Corporation Pty Ltd v Dart Industries Inc 13 IPR 385) and, consequently, is not objectionable under sec 40.

Conclusion

I have found that the opposition fails on all grounds relied upon
and I therefore award costs against BHP.   

O.L.Haggar
Delegate of the Commissioner of Patents

Patent attorneys for the applicant  :  Shelston Waters,

Sydney

Patent attorneys for the opponent   :  Griffith Hack & Co,

Melbourne