Air Products and Chemicals Inc v Linde Aktiengesellschaft

[1994] APO 15

official notice

decision of a delegate of the commissioner of patents

Applications       :  No. 601105 & No. 602620 in the name of AIR PRODUCTS AND CHEMICALS INC

Title:  Air separation process

Action: S.59 oppositions under the 1952 Act by LINDE AKTIENGESELLSCHAFT; hearing.

Decision:  Issued            .  Opposition to 601105 failed, application to proceed to sealing. Improvement invention not obvious because of surprising results. Grounds of opposition to 602620 established, claims not fairly based,  opportunity given for applicant to propose amendments. Common general knowledge discussed re obviousnsess and novelty.

patents act 1990

decision of a delegate of the commissioner of patents

Re:Patent Applications No. 601105 & No. 602620 by AIR PRODUCTS AND CHEMICALS INC and opposition under S.59 of the Patents Act 1952 by LINDE AKTIENGESELLSCHAFT.

background

Convention applications 601105 & 602620, for patents for inventions relating to an air separation process, comprise complete specifications lodged on 21 April 1989 and 13 December 1988 respectively, with priority claimed from applications lodged in the United States on 29 April 1988 and 14 December 1987 respectively. The applications were advertised accepted on 30 August 1990 and 18 October 1990, and opposed on 30 November 1990 and 18 January 1991. After both parties served their evidence, the matter was heard in Melbourne on 9-11 August 1993; the applicant was represented by Dr John Emmerson, QC, and Mr David Rainey, patent attorney; the opponent was represented by Mr Bruce Caine, of Counsel, and Mr Greg Noonan, patent attorney. The applicant's US patent counsel, Mr Willard Jones II and one of the inventors, Dr Douglas Bennett, were also present at the hearing.

application  no. 601105

the specification

The specification of 601105 indicates that the invention relates to a cryogenic process for the separation of air into its constituent components of oxygen, nitrogen and argon.  The process involves cryogenic distillation in an integrated multi-column system having a high pressure column, a low pressure column and an argon sidearm column.  In each of these columns, a liquid phase stream and a vapour phase stream are intimately contacted thereby allowing mass transfer.  The improvement of the invention is the use of a structured packing in place of distillation trays in the low pressure and argon sidearm columns; this results in increased argon recovery.  The specification details the three column distillation apparatus and the results of various tests using the structured packing.

Claim 1 reads as follows:

"In a process for the separation of mixtures, which comprise oxygen, nitrogen, and argon, by cryogenic distillation in an integrated multi-column distillation system having a low pressure column and an argon sidearm column wherein the argon sidearm column integrally communicates with the low pressure column, and wherein each column of the integrated distillation system, a liquid phase stream and a vapour phase stream are intimately contacted thereby allowing mass transfer; the improvement for increasing argon recovery comprises effectuating the intimate contact of the liquid and vapour phase streams in the low pressure column and the argon sidearm column by utilizing a structured packing."

Page 9 of the specification recites a definition which affects the scope of the claims, viz:

"By the term structured or ordered packing is meant a packing in which liquid flows over shaped surfaces in a countercurrent direction to the gas flow and wherein the surface is arranged to give high mass transfer for low pressure drop with the promotion of liquid and/or vapour mixing in a direction perpendicular to the primary flow direction."

grounds of opposition; the evidence

The opponent's notice of opposition referred to paragraphs (a) and (c) to (i) of sub-section 59(1) of the 1952 Act; however, only grounds of lack of novelty, obviousness and non-compliance with S.40 were pursued at the hearing.

The important parts of the evidence-in-support are summarized as follows:

.   A declaration by Mr Noonan dated 2 August 1991. Exhibit GJN-4 accompanying this declaration is a set of copied pages of a book entitled Mass Transfer Operations by Robert E Treybal, published 1955.  (Another declaration indicates that this book was available in Australia in 1962). The copied pages are directed to "packings" for distillation towers which generally provide for a large interfacial surface between liquid and gas but also which have a relatively large fractional void volume, or fraction of empty space. The packings must permit passage of large volumes of fluid through small tower cross sections without flooding and with low pressure drop for the gas. "Random" and "regular" types of packings are discussed.

.   A declaration by Gerard Norman Keith, dated 10 September 1991. Mr Keith is a chemical engineer who worked with air separation plants in Australia for twenty years.
Mr Keith declares, inter alia:
    that "structured packing has been available and used for about fifteen years in distillation processes",
    that "any competent engineer with experience in the distillation and air separation fields would routinely have considered structured packing as an option for column internals",    and that "the plant operator's two obvious choices .. would be to greatly enlarge the sidearm column, so increasing the number of trays, or to substitute structural packing in the column without increasing its size".

.   A declaration by Christopher Day, dated 21 November 1991. Mr Day, a chemical engineer currently managing an industrial plant which includes cryogenic separation of air, declares inter alia:
    that the features of structured packing were common general knowledge to distillation plant engineers in general, and to air separation engineers in particular, in Australia well before 1988, and
    that it was only natural and obvious that structured packing technology would be adapted to the cryogenic air separation process when the right conditions arose, eg. during the 1980's when the demand for argon increased.

.   A declaration by Mr Noonan dated 28 November 1991. Exhibit GJN-10 accompanying this declaration is a copy of a paper by V P Alekseev et al entitled "How mesh packings can be used in the rectification towers of air separation plants", translated from an original Russian article and published in a 1966 edition of Chemical and Petroleum Engineering (Alekseev I). This paper refers to using regular mesh type structured packings to improve the performance of rectification towers in air separation plants; details are given of the operation and results of a test plant which simulates the operation of part of a commercial plant.

.   Mr Noonan's declaration of 28 November 1991 also refers to exhibit GJN-11, another paper by Alekseev et al (Alekseev III); published, under similar circumstances to Alekseev I, in 1968.
(Other declarations indicate that the relevant editions of Chemical and Petroleum Engineering were available in Australia in 1967 and 1970). Alekseev III is a paper entitled "Investigation of the efficiency of slotted packings for low-temperature rectification of argon fractions". It refers to the operation and results of an experimental test column using "slotted" structured packings. There is some cross-referencing between the two papers by Alekseev et al.

The evidence-in-answer is summarized as follows:

.   A declaration by James Fair dated 17 July 1992.  Prof Fair, a chemical engineering academic at a Texas university, indicates that he has worked with and taught cryogenic air separation technology. He declares that he is unfamiliar with the state of the art in Australia, except that it lagged behind that in the US and Europe, with which he is familiar.

Prof Fair further declares, inter alia:
    that he is unaware of any published reference that teaches or suggests the use of structured packing in both the low pressure column and the argon sidearm column of an integrated multi-column distillation system for the cryogenic separation of air,
    that it is surprising that argon recovery could be achieved that was greater than what could be obtained with distillation trays prior to 1988,
    that the present invention, as claimed and as defined on page 9, has distinct advantages over the apparatus described in Alekseev I and Alekseev III,
    that the slotted packings described in Alekseev III have no practical application to industrial air separation plant design, and would lead to the continued use of conventional distillation trays, and
    that the invention would not have been obvious to him, given the substantial benefits relating to the increased argon yield.

.   A declaration by Christopher Fell dated 16 July 1992.  Prof Fell, an Australian academic, states that he is the author of 30 publications in international journals in the area of distillation column design, and that his design procedures have been cited in the authoritative Chemical Engineers Handbook (1984). He also declares inter alia:
    that cryogenic distillation columns for the recovery of argon from oxygen require very different technology from that used for the separation of hydrocarbons,
    that he is unaware of any prior art involving the use of structured packing in both the low pressure column and the argon sidearm column,
    that the invention's increase in argon recovery is surprising,
    that the slotted packings in Alekseev III generate a series of parallel channels, without any exchange of either gas or liquid between these channels, and are inappropriate for application to commercial air separation plants, and
    that prior to 1988 it would not have been obvious to him to increase argon recovery by utilizing structured packing in the low pressure column and the argon sidearm column in an industrial commercial plant.

The evidence-in-reply can be summarized as follows:

.   A declaration by Mr Keith dated 25 March 1993. In this declaration, Mr Keith refers to the applicant's definition on page 9 of the specification, he refers to the known packings discussed in GJN-4 (in the evidence-in-support previously referred to), and declares inter alia:
    that it is not clear what is meant by "mixing in a direction perpendicular to the primary flow direction",
    that the specification gives no description of the packing on which the reported results and conclusions are based,
    that apertures, openings and slots are a common feature of commercial structured packings,
    that the reference to "slotted packings" in Alekseev III means that the packing contains slots of a well known type, and
    that in any structured packing used in distillation processes there must be mixing between the liquid and vapour streams for there to be mass transfer.

.   A declaration by Anton Moll dated 6 April 1993.  Mr Moll, an employee of Linde Aktiengesellschaft, the opponent, construes Alekseev I and Alekseev III as a single disclosure, and declares inter alia:
    that Alekseev III discloses slots, ie. rectangular openings in the packing sheets, and
    that the high efficiency of the slotted packing can only be explained by a very good radial dispersion of the phases, ie. a very good mixing perpendicular to the primary flow direction.

section 40

Mr Caine submitted that the definition of a "structured packing", on page 9 of the specification, was not clear and that this rendered the claims unclear. He argued that the phrases "shaped surfaces" and "high mass transfer for low pressure drop" are non-limiting and imprecise. He also argued that the clause "the promotion of liquid and/or vapour mixing in a direction perpendicular to the primary flow direction" was unclear. Mr Keith deals with this matter in paragraph 4 of his declaration of 25 March 1993, viz.

"...I note that the language...provides no information as to what is envisaged by this element in relation to the actual detailed configuration of the structured packing...it is wholly unclear as to whether perpendicular surfaces are required, or surface structures of some other kind, or transverse openings, or surface configurations on vertical channels of a particular kind, or internal structural features..."

Dr Emmerson submitted that the definition is clear if read in the light of the sentence following the definition on page 9, which lists seven US patent specifications as examples of ordered or structured packings. Copies of these patent specifications are included as exhibit GNK-1 accompanying Mr Keith's declaration of 25 March 1993.

The US patents show various arrangements of packings of the type described as "regular" in Treybal, referred to above. I deduce that "regular" and "structured" are both terms used to describe packings that are not random. Treybal describes random packings as "those which are simply dumped into the tower during installation and allowed to fall at random." They are shown as having various shapes such as rings, cylinders and "saddles". The regular packings described in Treybal show arrangements of rings, cylinders, bent sheets, and the like which have been stacked in symmetrical or regular configurations. They are said to "offer the advantage of lower pressure drop and greater possible throughput of fluids, usually at the expense at least of more costly installation than random packings."  The particular arrangements shown in Treybal all appear to me as though there would be some interruption of the direct vertical line of flow of the mass transfer fluids; ie. there would be some component of movement of the fluids in a direction perpendicular to the primary flow direction. However, Treybal points out that the packings shown are by no means the only ones used and that many others are available, so it seems possible that there have been some arrangements with no or minimal perpendicular fluid flow. This evidence, along with other evidence before me, suggests that a "structured packing" generally is likely, but not definitely, to cause some mass transfer fluid flow and mixing in a direction other than the primary flow direction.

The seven US patents referred to on page 9 of the specification show structured arrangements such as diagonally alternating and overlapping corrugated sheets, or plates with crossing channels. All the arrangements are such that there would be interruption to direct flow in the primary flow direction, ie. there would be a component of the direction of flow in the perpendicular direction.

I am satisfied that a skilled addressee would be able to clearly construe the definition of structured packing on page 9 of the specification.  Firstly, I think that it is elaborated by and consistent with the disclosures in the US patents; the definition seems to me to be a slightly narrower definition than the more general version discussed above; ie. it excludes any structured packing which does not promote some flow in the perpendicular direction.  Secondly, a fair reading of the definition, in the light of the US patents and other evidence, suggests that "promotion ...of mixing in a direction perpendicular to the primary flow direction" only requires a component of the flow or mixing to be in the perpendicular direction, ie. oblique flow is included.  Finally, I think that it is not necessary for the definition to refer to particular configurations, as suggested by Mr Keith. The configurations are exemplified by the US patents,  and the specification suggests that the specific configurations are not a feature of the invention. After referring to the list of US patents on page 9, the specification goes on:

"These patents disclose specific examples of structured (ordered) packings, however, they do not present an exhaustive list of examples.... it is not the intention to prefer one type of structured packing over another. All types of structured packings are believed to be applicable to the present invention... the performance of these packing elements are reasonably well known for hydrocarbon separations, however, no suggestions of this use appear in the art for the cryogenic separation of air."

Mr Caine argued that the reference to "all types of structured packings.." in the paragraph cited above implied that the invention is not limited to the types exemplified by the US patents. I do not agree with this interpretation because it does not take into account the previous definition statement; when the definition and the US patent examples are taken together, I think the reference to "all types of structured packings.." in the paragraph cited above means all types of structured packings as defined.

novelty

Mr Caine made the following submissions in relation to interpretation of the Alekseev documents:
    The mesh packing in Alekseev I can be considered as a structured packing.
    The slots in the "slotted packings" in Alekseev III are slots in the plates of the packing, and this allows mixing in a direction perpendicular to the vertical primary flow direction when flow occurs along the horizontal edges of the slots.
    Many of the US patents in GNK-1 show slots in the plates of the structured packing, this implies that slots are a well-known feature of structured packing.

Dr Emmerson disputed Mr Caine's interpretation of the reference to "slotted packings" in Alekseev III. The former submitted that the "slots" are vertically aligned holes between layers of flat and corrugated plates, which are shown in a cross-sectional figure of the packing; ie. they are not slots in plates as suggested by Mr Caine. Dr Emmerson referred to parts of the evidence to support his submissions, including another document by Alekseev et al, Alekseev II, which uses a similar packing to that in Alekseev III.  Alekseev II refers to "vertical channels"  being "formed by corrugated and flat sheets arranged in turns".

Mr Caine responded to Dr Emmerson's submissions by pointing out that Alekseev III also referred to "channels", and that the reference to "slots" therein therefore must mean something more than the channels. Alekseev III reads: "The slotted packing unit is a combination of vertical channels of a sinusoidal form."

There is some doubt as to the exact meaning of the above sentence in Alekseev III, due possibly to the translation from the Russian original, but Dr Emmerson's interpretation of the disclosure in Alekseev III seems more plausible to me than Mr Caine's. The figures in Alekseev III support the former interpretation, but the latter relies on interpretation of the text in the light of other documents; even if it were to be established that slotted plates were common knowledge, there is still no evidence that slotted plates have been used in the packings in Alekseev III. Thus I conclude that there is no disclosure of slotted plates in Alekseev III.

The slots or channels in the packing in Alekseev III appear to be aligned only in the vertical direction, and the arrangement does not appear to be conducive to oblique or perpendicular flow of the mass transfer fluids. Also, the figures in Alekseev I do not disclose any alignment of the packing referred to in that document. So, even though the packings in the Alekseev documents could be described as "structured packings" within the general definition referred to above, I am of the view that the Alekseev packings are outside the scope of packings envisaged for the present invention, as defined on page 9 of the specification.

Mr Caine submitted that the combination of the Alekseev I and Alekseev III documents discloses all the essential features of claim 1 of the applicant's specification.

He also submitted that the test for novelty allows consideration of a cited document in the light of common general knowledge at the date of the citation, and allows consideration of whether a claim is directed to a mere workshop improvement. In support of these submissions, he cited passages from Werner v Bailey (1989) 85 ALR 679, Nicaro v Martin (1990) 91 ALR 513, Acme Bedsteads v Newlands (1929) 58 CLR 689 and Hill v Evans (1862) 31 LJ Ch 457.

The Alekseev documents relate to a single column experimental model and do not refer to "an integrated multi-column distillation system" having the three columns defined by claim 1. However, Mr Caine argued that this difference was a matter of common general knowledge, ie. a skilled addressee would apply the discovery of the Alekseev documents to the prior art integrated multi-column systems, shown for example in fig.1 of the applicant's specification. He also suggested that reference to an "upper column" in Alekseev III implied that there must be a lower column, and that the column shown in Alekseev III is an experimental version of an argon column in the multi-column system.

Dr Emmerson submitted that the Alekseev documents do not disclose the present invention for the following reasons:
    The citations do not disclose use of a structured packing as defined on page 9 of the specification.
    The Alekseev documents disclose only benchtop simulation apparatus; they do not relate to a commercial plant, do not discuss increasing argon recovery and do not show the low pressure and sidearm columns in the present invention.

Dr Emmerson suggested that the Alekseev documents failed the practicality test set out in Hill v Evans, supra. In that judgement Lord Westbury said:

"..the antecedent statement must be such that a person of ordinary knowledge of the subject would at once perceive, understand, and be able practically to apply the discovery without the necessity of making further experiments and gaining further information before the invention can be made useful."

In this matter I think it is important for me to first establish whether the multi-column type of cryogenic distillation system of the present invention was well known at the date of publication of the Alekseev documents, ie. in 1966 and 1968. Mr Caine pointed out that Alekseev III referred to "the upper column of a KT-3600 air separator"; but I have no evidence before me to indicate whether a "KT-3600" is of the said multi-column type. The reference to an upper column may imply that there must be a lower column but I think the implication cannot be extended to a sidearm column. The declarations of Messrs Keith and Day in the evidence-in-support indicate that multi-column systems were known prior to 1988; but this leaves some doubt whether they were known in 1966 or 1968. The evidence-in-reply does not address the issue. Also, there is no evidence to suggest that the column in Alekseev III is an experimental version of an argon sidearm column, as suggested by Mr Caine.  On the other hand, both professors Fair and Fell declare that they are unaware of any published reference that teaches the use of structured packing in both the low pressure column and the argon sidearm column of an integrated multi-column system. Thus I conclude that the evidence is insufficient to prove that the integrated multi-column type of system was well known at the time of publication of the Alekseev documents.

In deciding the novelty issue, I shall apply the reverse infringement test. Infringement of a claim occurs when all the essential integers of the claim have been disclosed in the citation. In the present case, the specification and the evidence indicates that the features in claim 1 of (i) an integrated multi-column distillation system, including an argon sidearm column, and (ii) a process for increasing argon recovery in such a system, are essential features of the invention. These features are not disclosed in the Alekseev documents, and furthermore, because there is no evidence that the integrated systems were well known at the time of publication of the cited documents, it is also not appropriate to conclude that the documents can be read in the light of that supposed common general knowledge to disclose the said essential features of claim 1. So I conclude that claim 1 is novel in the light of the Alekseev documents because the apparatus disclosed in the Alekseev documents would not infringe claim 1.

Because I have decided novelty on the issue above, I think it is not necessary for me to now consider, with regard to novelty, the issues of whether (i) structured packing as defined in the specification was well known at the dates of publication of the citations, or (ii) the citations can be read in the light of this common general knowledge to disclose structured packing as defined.

obviousness

The specification indicates that the invention is an improvement over the prior art: it is recognized that structured packings as defined have been used for hydrocarbon separations but not for the cyrogenic distillation of air.

In this matter Mr Caine submitted that the opponent's evidence shows that:
    Structured packings were well-known in Australia before the priority date.
    The benefits and disadvantages of structured packing were well-known; the former being reduced pressure drop, and the latter being that structured packing was expensive and resulted in a distillation column of greater than normal height.
    The benefits and disadvantages of all forms of packing were normally taken into account as part of the routine process of design of cryogenic distillation plants, and had the conditions been right with regard to demand for argon, structured packing would have been chosen.

Mr Caine also submitted that Prof Fair's declaration is not relevant because the latter admits that he was not familiar with the state of the art in Australia.

In support of the applicant's contention that the invention is not obvious, Dr Emmerson referred to the evidence and submitted that:
    The "option" of using structured packings in the art of cryogenic distillation of air was not considered to be satisfactory because of the problem of extra height in the column; but the invention shows that in fact the height can be kept down.
    The teaching in the art before the priority date showed that distillation trays had certain advantages and therefore it was not obvious to use structured packing.
    There has been a long-standing need for argon, and the argon yield of the invention is a "surprising" result.
    Prof Fair's evidence is relevant because (i) he declares that the invention is not known in the United States or Europe, (ii) he declares that Australia was not as advanced as the US or Europe in the art, and (iii) the opponent has not made out that Australia was "at the cutting edge of this technology".

I think it is important to first establish whether or not structured packings as defined on page 9 of the specification were common general knowledge at the priority date of the specification, ie. in 1988. In considering this matter I take account of the following:
    The specification clearly indicates that the inventive concept relates to the use of the packings, not to the packings  per se.
    The specification states that the packings are "reasonably well known for hydrocarbon separations".
    The seven US patents referred to on page 9 of the specification became available in Australia in the early 1980's; and these all show arrangements which would promote some perpendicular fluid flow.
    The arrangements shown in Treybal all appear as though there would be some mixing of fluids in a direction perpendicular to the primary flow direction.

On the specification and evidence before me, I think it is reasonable to conclude that structured packings as defined in the specification were a matter of common general knowledge before the priority date of the specification, at least for hydrocarbon separations but not for the cryogenic distillation of air.  Even though I have concluded earlier that, in a general sense, it may be possible that some "structured packings" could include arrangements where there may be no or minimal perpendicular fluid flow (as shown in Alekseev III for example), I think the more specific structured packings as defined in the present specification are the commonly known type. This could be construed from the specification per se; there is no evidence that the specification is attempting on page 9 to distinguish the structured packings applicable to the invention from a broader well-known class of structured packings: if this was the intended meaning it would have been more likely that the specification would have used another expression such as "perpendicular-flow structured packings" or the like. In other words, the specification seems to be simply defining what the inventor perceives to be the well-known structured packings in the hydrocarbon art, notwithstanding that there may be other packing structures (such as that shown in Alekseev III) which don't quite fit the definition.

Useful tests for obviousness are given by Aickin J in The Wellcome Foundation Limited v VR Laboratories (Aust) Pty Ltd (1981) 148 CLR 262, viz. at page 270:

"..the question of obviousness involves asking the question whether the invention would have been obvious to a non-inventive worker in the trade equipped with the common general knowledge in the trade as at the priority date, without regard to documents in existence but not part of such common general knowledge."

And at page 286:

"The test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not."

The specification indicates that the problem to be solved in this case is an inefficient argon yield in systems using distillation trays. The solution is to use structured packings, the benefits being:

1. Low pressure drop per theoretical stage, this results in:
    (i) lower feed air pressure (and energy savings), and

(ii) increased volatility of argon and nitrogen relative to oxygen, which in turn improves the separation of argon.

2. With regard to the number of theoretical stages in the distillation columns, structured packing "surprisingly" allows a continuous increase in recovery with the number of stages, whereas with trays "recovery is found to increase initially and then pass through a maximum value". This contributes to a "remarkable and unexpected result" in that "it is possible to achieve increases in argon recovery to more than 90% of the theoretical maximum; whereas only 60% of the theoretical maximum can be achieved for any number of tray distillation stages".

The declarations of Messrs Keith and Day, referred to earlier in this decision, are relevant to the opponent's case in this issue; they declare that it would be a routine step to use structured packing instead of trays. For example, in paragraph 11 of his declaration of 10 September 1991, Mr Keith states:

"I do not consider that the described improvement in argon recovery was at all remarkable and unexpected in Australia prior to April 1988. In the well known 3-column process of the kind exemplified by figures 1 and 2 of the subject complete specification, the argon sidearm column .. is an `optional extra' which achieves recovery of typically a 0.5% fraction of argon, whereas argon is present in air at sea level as approximately a 1% fraction. Thus, in a typical installation, only 50% of the available argon is recovered - in contrast to the 99% recovery of oxygen. The argon sidearm column is a small unit and there is usually no justification for a higher argon recovery. If a higher argon recovery was required in a particular case, the plant operator's two obvious choices, now and prior to April 1988, would be to greatly enlarge the sidearm column, so increasing the number of trays, or to substitute structural packing in the column without increasing its size. Either modification would increase the cost of the plant, but would inevitably and substantially improve argon recovery from the typical low figure."

Without resolving the issue of the relevance of Prof Fair's evidence because he is unfamiliar with the art in Australia, I note that his evidence is mainly directed to the Alekseev documents and the issue of novelty, even though he does express a brief opinion on obviousness.

Prof Fell's evidence I think deals with matters in some depth which are more relevant to the issue of obviousness. Consider the following paragraphs in his declaration:

"4     I would comment that the design of cryogenic distillation columns, especially those for the recovery of argon from oxygen, requires a very different technology from that used for the separation of hydrocarbons, largely because of the need to accommodate the low temperatures... Equipment design must be based on a consideration of heat loss from the distillation column. Conventional cryogenic columns use relatively low superficial gas velocities, and rely on highly efficient small hole sieve trays to minimise the column height required to effect separation.....a distillation column design engineer [would conclude] that available structured packings would not be considered to have a sufficiently high separation efficiency per unit column height under the prevailing operating conditions to be a suitable alternative to high efficiency seive trays in cryogenic distillation."

"7     Figures 3 and 4 of ...Application No.601105 quantify the improvement of the invention, namely the increase in argon recovery over and above the maximum argon recovery which can be obtained with distillation trays when structured packing is used in the low pressure column and the argon sidearm column. Because the invention's increase in argon recovery is over and above the maximum argon recovery which can be obtained with trays (ie. even if an infinite number of trays were used) I would characterize the invention's increase in argon recovery as surprising."

In paragraph 27 of his declaration, Prof Fell responds to paragraph 11 of Mr Keith's declaration, viz:

"...I state that argon recoveries of 80-90% have been achieved by argon columns for the past 50 years or so. Furthermore, increasing the number of separation stages in the argon column may have an effect on argon purity but it will have little effect on argon recovery... Finally, it was not known prior to the [present] invention ... that the substitution of packing in the argon column without changing its size would lead to an increase in argon recovery...."

The evidence suggests to me that it is likely that the advantages of the invention due to the reduced pressure drop are matters which would have been predicted by a worker skilled in the art; however, there is insufficient evidence to conclude that the same worker would have predicted the advantages due to the discovery of the continuous increase in recovery with the number of stages. The specifications of applications 601105 and 602620 suggest that the advantage of higher efficiency per unit height is associated with the latter application more so than with the former. Some of the submissions in this matter were confusing the two inventions, so I have placed less weight on this particular advantage in the present case. However, the surprising increase in recovery due to the discovery of continuous increase with the number of stages, seems to be a characteristic of the present invention which has some merit. I note also that this characteristic has not been disputed by the opponent's declarants.

Also at issue is over what period there was a long-standing need to increase argon yield from cryogenic air distillation plants. Mr Day states in paragraph 6 of his declaration:

"In the past twenty years or so there has been a requirement to also produce argon....With the onset of the semiconductor industry, for example, the demand for argon over the past ten years has increased dramatically."

And in paragraph 9 he states:

"It is my opinion that it was only natural and obvious for the proven but more expensive packed column technology in general, and structured packing technology in particular, to be adapted to the cryogenic air separation process where the right conditions arose. The conditions did arise during the 1980's with plant operators requiring the process to maximise argon yield with the graetest degree of plant technology."

Mr Noonan's declaration of 2 August 1991 was accompanied by a copy of Australian Patent Specification No.91616/82 as Exhibit GJN-1. That specification, lodged in 1982, refers to the background of the invention in the following terms:

"Recently the demand for argon has increased dramatically due primarily to the use of argon in the refining of stainless and other steels."

This evidence suggests that an increased demand for argon occurred in the early 1980's and that there has been a long-standing need well before the priority date of the present invention, ie. April 1988. This adds weight to the applicant's contention that if the invention had been obvious it would have been discovered before the priority date of the present invention.

Taking all these matters into account, I am satisfied that the invention is not a case where the non-inventive worker in the trade would have taken routine steps from the prior art to the invention. Some advantages of the invention could be construed as being obvious, but at the same time there are some elements of surprise in the invention; and in this sense I think this case aligns with the cases of Muntz v Foster (1843) 2 WPC 93 and Pope Appliance v Spanish River Pulp & Paper Mills (1929) 46 RPC 23 where invention was found in surprising results in the use of known devices.

Thus I find that the invention claimed in application 601105 is not obvious.

application  No. 602620

the specification

This invention also relates to cryogenic separation of air using structured packing. "Structured packing" is defined in the same way as in application 601105. The present specification is more directed to the efficient recovery of both argon and oxygen, cf. the emphasis on argon recovery in application 601105. Claims 4 and 3 are the broadest claims in 602620 and read as follows:

"4.      A method for improving a cryogenic distillation apparatus having at least one distillation column system for the separation of mixtures containing oxygen and argon, comprising the step of replacing the distillation trays in the at least one distillation system with a structured packing in at least those regions of the distillation column system where the concentration of argon is in the range from 0.6 to 75 volume percent."

"3.      In a process for the separation of mixtures, which comprise oxygen and argon, by cryogenic distillation, wherein in certain regions of a distillation column system having at least one column, a liquid phase stream containing oxygen and argon, and a vapour phase stream containing oxygen and argon, are intimately contacted thereby allowing mass transfer which enriches the liquid phase stream with oxygen and strips argon from the liquid phase stream, and enriches the vapour phase stream with argon and strips oxygen from the vapour phase stream, the improvement comprising effectuating intimate contact of the liquid and vapour phase streams utilizing a structured packing in at least those regions of the distillation column system where argon concentration is within the range from 0.6 to 75 volume percent, and operating the process such that the densimetric superficial gas velocity in those regions is at least 0.06 feet per second."

The specification describes the development of the invention, viz:
    Experimental units were constructed with structured packing, and flow rates and other basic data was obtained from regression analysis of the experimental units.
    A computer-based mathematical model was developed which predicted the theoretical height of the packing in each stage of the column (HETP).
    The efficiency of the experimental units was then compared with the model, the data for this purpose being divided into three groups, viz: (i) nitrogen/oxygen, (ii) argon/oxygen (where the argon concentration ranged from 82.5 to 97 volume percent), and (iii) oxygen/argon (where argon ranged from 0.6 to 85 vol%).

    The third set of data was found to give results "more than 10% better" than the theoretical model. The specification states on pages 12 and 13:

"This is another indication that there is some additional mechanism which enhances the mass transfer performance in this range of argon concentrations in oxygen."...."a remarkable and unexpected performance. For example, the HETP can be as low as 6.8 inches, when the expected (predicted) value is 8.5 inches."...."a distinct benefit of using structured packing is seen; this benefit is the fact that the height required for structured packings are[sic] comparable to the height for distillation trays to achieve the same overall separation while retaining the lower pressure drop advantages."

The specification also indicates that there are energy savings resulting from the present invention.

grounds of opposition; the evidence

The opponent's notice of opposition referred to paragraphs (a) and (c) to (i) of sub-section 59(1) of the 1952 Act; however, only grounds of lack of novelty, obviousness and non-compliance with S.40 were pursued at the hearing.

The important parts of the evidence-in-support are summarized as follows:

.   Three declarations by Mr Noonan dated 18 October 1991, 18 December 1991 and 16 April 1992. This evidence inter alia includes copies of evidence served in the opposition to application 601105. Exhibit GJN-3 is a copy of a manual entitled "Separation Columns for Distillation and Absorption" issued by Sulzer Chemtech.

.   A declaration by Mr Keith dated 20 November 1991. This declaration reiterates many of the points in his declaration of 10 September 1991 relating to 601105, including reference to the Alekseev documents. Re application 602620, he also declares:
    that the use of "at least" in line 6 of claim 4 includes within the scope of the claim arrangements where structured packing is distributed throughout the system,
    that the lower limit of argon in claim 4 is a meaningless restriction since the concentration of argon in air is typically higher than 0.6 volume percent, and
    that the upper limit is not significant because the regression analysis results described in the specification would vary with the nature of the structured packing used by the applicant,
    that the specification is deficient because no details have been given of the structured packing used,
    that the decrease in HETP above a given densimetric superficial gas velocity is not at all surprising.

The evidence-in-answer is summarized as follows:

.   A declaration by Prof Fell dated 16 July 1992. This is similar to his declaration in the evidence-in-answer in 601105. Specifically with regard to the present invention he declares:
    that the process for deriving the regression constants was sound and would not be a function of the structured packing used,
    that the Alekseev documents would have discouraged him from pursuing the use of structured packings,
    that the range of 0.6 to 75 percent volume referred to in the claims is not meaningless because there are a significant number of stages of separation outside this range in a modern separation plant which generate high purity argon, and
    that the specification fully supports the invention as claimed because it is justifiable to extrapolate from the experimental data provided which is merely exemplary of the invention claimed.

.   A declaration by Prof Fair dated 17 July 1992. This declaration is similar to that made in relation to the opposition to 601105; he compares the invention as claimed with the Alekseev disclosures and states that the invention would not have been obvious to him.

The evidence-in-reply consists of declarations by Messrs Keith and Moll dated 25 March 1993 and 6 April 1993 respectively. As was the case with opposition to 601105, the declarants discuss the issue of slotted structured packings coming within the definition of structured packings in the specification. Mr Keith also reiterates his earlier comments that the results of the present invention depend on the nature of the particular structured packing used; he refers to page 8 of the specification where it is stated that particular constants "are obtained from numerical regression of raw data for a particular system."

section 40

Mr Caine submitted that the specification failed to comply with S.40 in the following ways:

(i) The definition of "structured packing" is indefinite.

(ii) The specification discloses particular packing geometry in particular regions of a particular distillation system which gives an improvement in separation efficiency. However the claims, which rely on values, are merely directed to all geometries in all types of systems; and are therefore not fairly based on the invention disclosed. In this regard Mr Caine also referred to the feature of the superficial gas velocity in claims 1-3 but not in claim 4.

(iii) The best method of performing the invention is not disclosed because the type of structured packing has not been identified; this is necessary to repeat the applicant's experiments to give the stated benefits of the invention.

In reply, Dr Emmerson emphasised the "precise" definition of "structured packing" in the specification; he suggested that the opponent's declarants have not appreciated the restriction on the meaning of "structured packing". He also submitted that the definition is not indefinite because Mr Keith and Professors Fell and Fair all refer to the definition and apparently understand the meaning.

Dr Emmerson submitted that the claims were not avaricious because the specification indicates that there is an improvement over the prior art when the packing as defined is used; all the features claimed are a "valid generalization". With regard to the best method of performing the invention, he submitted that the specification does disclose a method, which includes examples of the types of packing, and there is no evidence from the opponent that this method is not the best.

The matter of the definition of structured packing I have dealt with in my earlier discussion of application 601105; my previous comments are equally relevant to application 602620; ie. a skilled addressee would be able to clearly construe the definition.

In the matter of whether the invention is fully described, I note that Mr Keith considers this matter in considerable detail, indicating the opponent's serious convictions on this ground. However, Prof Fell's in-depth submissions are of a similar weight to Mr Keith's. To me, there is some doubt in the matter: the Sulzer Chemtech manual (on page 9 for example) does seem to indicate that the performance of distillation columns is generally dependent on the actual structure of the packing used, but the present specification is perfectly clear on the matter, ie. any structured packing (as defined) will do. It was submitted at the hearing that there may be a problem with utility of the invention: this may be so if some structured packings fail to give the benefits of the invention. However, with regard to sufficiency, the weight of the evidence is not in favour of the opponent; I think it is likely that a skilled addressee could practise the invention as described and I am inclined to resolve any doubt in the matter in favour of the applicant.

In the matter of fair basis, I agree with Mr Keith's interpretation of the effect of "at least" on the scope of claim 4. I note that this was not disputed by the applicant's declarants. In fact, all the independent claims refer to structured packing being "at least in those regions of the distillation column where the concentration of argon is in the range from 0.6 to 75 volume percent". This clause allows the scope of the claims in general to include structured packing in regions of other argon concentrations: the 82.5 to 97 vol% region for example. However, the description of the invention clearly indicates that it is specifically based on the selection of the 0.6 to 75 vol% argon range because the surprising benefits of the invention only occur in that range. Thus I conclude that the independent claims are too broad because they allow for the inclusion of methods which are inconsistent with the invention described; see Mond Nickel Co Ltd's Application [1956] RPC 189 at 194.

The matter of construction of claims containing the expression "at least" was dealt with by the Federal Court in Yamazaki Mazak v Interact Machine Tools (1991) 22 IPR 79. At page 97 Gummow J states:

"Secondly, Interact and IMT point to the integer in the 4th paragraph of the claim of each of the petty patents that the first and second tool rests, associated with the first and second spindle stocks respectively, which are both disposed, with respect to the frame, to one side of the common axis, both be moveable "at least in a direction perpendicular to the common axis". The phrase "at least" indicates that the claim leaves open the possibility of movement in a direction other than in a direction perpendicular to the common axis, for example, parallel to the Z axis. Then it is submitted that the only disclosure, at least in the first 12 of the Japanese basic applications, is of tool rests moveable in directions perpendicular to the common axis.

In response to this second submission, counsel for Yamazaki submitted (and I accept) that the possibility of movement in an additional direction was not a feature of the invention. It was not a limitation of the claims, the expression "at least" being something left open for inclusion as an additional feature, but not specified as an integer."

In my view, the present circumstances can be distinguished from those in the Yamazaki case. In the present case, which relates to a selection of a specific range, "at least" leaves the claims open to include a feature which is inconsistent with the invention described and which is beyond the specific range selected; whereas in the Yamazaki case, which is not related to a selection, "at least" merely leaves the claims open to include an optional feature which is prima facie compatible with the invention described.

Returning to the matter of present claim 4, I think this claim is also not fairly based on the specification because it does not include the essential feature of the densimetric superficial gas velocity being "at least 0.06 feet per second". See AMP v Utilux, (1971) 45 ALJR 123 and Mergenthaler Linotype Co's Application [1958] RPC 278. The gas velocity feature can be construed as an essential feature since:
    figure 3 of the drawings shows that the benefits of the invention only occur above this mininum velocity,
    the specification, at lines 14-16 on page 14, indicates that at values less than 0.06 the experimentally measured values did not exceed the theoretical values,
    both of the applicant's declarants suggest that the feature of "gas velocity limitation" is significant; (see paragraphs 17, 21 and 28 of Fell and paragraphs 4 and 18 of Fair).

Thus I conclude that claims 1-4 are not fairly based because they are inconsistent with the description and claim 4 is also not fairly based because it fails to define an essential feature of the invention.

novelty

The opponent's submissions on novelty were similar to those made in opposition to application 601105. Only claim 4 of the present application was challenged by the opponent.

I have decided that the claims in 601105 are novel in the light of the Alekseev documents because the latter do not disclose an integrated multi-column distillation system, including an argon sidearm column, and a process for increasing argon recovery in such a system, which are features of the claims of 601105. However, claim 4 of 602620 is not restricted to a process in an industrial-type system, it is broad enough to include an experimental system as disclosed in Alekseev III for example. Also, I think "at least" in line 6 of claim 4 would allow arrangements where structured packing is used in all the regions of the column, not just the 0.6 to 75 vol% range. In this light, the only prima facie difference between claim 4 and the disclosure in Alekseev III is that structured packing specifically according to the definition in the specification is used in the invention, whilst Alekseev III uses structured packing without fluid mixing in a direction perpendicular to the primary flow direction.

Mr Caine submitted that in considering novelty a disclosure can be read in the light of the common general knowledge at the time of the disclosure. I agree that this is a correct view of the law, based on the cases he referred to; bearing in mind though that there are several ways to deal with questions of novelty.

With regard to application 601105 and the matter of obviousness, I have already established that structured packings as defined in the specification were common general knowledge at the priority date of that application; but that conclusion took into account a disclosure in the specification and seven US patents all of which were published, before the priority date of 601105, but after the date of publication of Alekseev III.

The extract from the book Treybal is the only reference in the evidence which was published before the date of publication of Alekseev III. This reference is significant though, since the arrangements shown therein all appear as though there would be some mixing in a direction perpendicular to the primary flow direction. In deciding the appropriate weight to be given to this evidence, I firstly note the following matters:

.   Mr Keith, in paragraph 22 of his declaration in the evidence-in-support, states that Treybal is "the well known standard textbook".

.   The present specification refers to Treybal in line 9 on page 7, and uses the theory therein as the basis for calculations in the method of the invention.

I thus suspect that the disclosure of structured packings in Treybal, available in Australia in 1962, was common general knowledge in the technology of distillation at the date of publication of Alekseev III, ie. 1968. However, I think the abovementioned references are not quite sufficient to prove the matter conclusively, and the opponent's evidence does not specifically address this issue: so there is still some doubt in the matter.

Even if the abovementioned matter of common general knowledge was conclusively proven, I would still have some doubt whether Alekseev III anticipates present claim 4 according to the law. It could be argued that a person skilled in the art, a chemical engineer for example, when given a copy of Alekseev III, may have construed the citation in the light of this common general knowledge and considered the possibility of using a structured packing which promotes perpendicular flow as an alternative to the structured packing actually shown in the figures of Alekseev III. However, this possibility is insufficient to prove anticipation, which requires "clear and unmistakable directions as to what the patentee claims to have invented". See Flour Oxidizing v Carr (1908) 25 RPC 428 at 457. Alekseev III does not have clear and unmistakable directions to use structured packings which promote perpendicular flow. Even though such packings were commonly known, they were not the only type available, and the vertical slot packings in Alekseev III seem to offer an alternative to the well known type. I think it is appropriate to resolve any doubts in this matter in the applicant's favour.

An alternative way to deal with the matter is to apply the reverse infringement test; which is current Patent Office practice. Since Alekseev III does not disclose the use of packings which promote perpendicular flow, the citation could only be construed as an anticipation if perpendicular flow is an inessential requirement of the packings claimed. See Catnic Components v Hill & Smith [1981] FSR 60 at 66. However, the evidence before me suggests that the requirement for the packings to promote perpendicular flow is of some importance; eg. Prof Fell suggests that the perpendicular flow promotes mixing of the mass transfer liquids. Thus I am not prepared to conclude that the promotion of perpendicular flow is an inessential feature of claim 4.

Finally, I am of the view that the disclosure in Alekseev I does not add anything to the opponent's case. This document also discloses structured packings with what appear to be vertical channels, and like Alekseev III, seems to offer an alternative to the commonly known type used in the present invention.

Therefore, I conclude that claim 4 of application 602620 is novel in the light of the Alekseev documents.

obviousness

The submissions on obviousness were relatively brief and along the same lines as those made in the opposition to 601105. Only claim 4 of the present application was challenged by the opponent.

In my view, the specification and evidence indicates that the inventive concept in the present case includes inter alia the features of:
    (i) structured packing only in those regions of the distillation column system where the concentration of argon is in the range from 0.6 to 75 vol% and
    (ii) a gas velocity in those regions at least 0.06 feet per second.

Any claim that includes these features, as well as being fairly based, will also define inventive subject matter, because these features define an arrangement which has somewhat surprising advantages over the prior art; ie. an improvement in the yield of oxygen and argon.  As I have already discussed in relation to 601105, the law is such that an invention is not obvious if it contains an element of surprise to a person skilled in the art.

conclusion

I have found that the opposition to application 601105 has failed on all grounds and that there is no lawful ground of objection to the application and complete specification. I direct therefore that the application and complete specification proceed to sealing, subject to any appeal.

I have also found that the opposition to application 602620 has been successful because claims 1-4 are not fairly based. However, I think there is patentable subject matter in the specification and thus I allow Air Products and Chemicals Inc. 60 days from the date of this decision to propose amendments to overcome the objection to the specification.

In the matter of costs I follow the usual practice of costs following the event and award costs in the matter of application 601105 against Linde Aktiengesellschaft and in the matter of application 602620 against Air Products and Chemicals Inc.

John Welsh
Delegate of the Commissioner of Patents

Patent attorneys for the applicant  :  Thomson Pizzey, Canberra.

Patent attorneys for the opponent   :  Davies Collison Cave,   Melbourne.