Rio Tinto Alcan International Limited v NorthEastern University, Shenyang Beiye Metallurgical Technology Co. and NorthEastern University Engineering & Research Institute Co. Ltd
[2014] APO 79
•1 December 2014
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Rio Tinto Alcan International Limited v NorthEastern University, Shenyang Beiye Metallurgical Technology Co. and NorthEastern University Engineering & Research Institute Co. Ltd, [2014] APO 79
Patent Application: 2007348559
Title:Electrolytic cells for aluminum having cathode carbon blocks with heterotypic structure
Patent Applicant: NorthEastern University, Shenyang Beiye Metallurgical Technology Co. and NorthEastern University Engineering & Research Institute Co. Ltd
Opponent: Rio Tinto Alcan International Limited
Delegate: Dr N.R. Madsen
Decision Date: 1 December 2014
Hearing Date: 30 September 2014, in Canberra
Catchwords: PATENTS – section 59 – opposition to grant of a patent – dismissal consideration – determination of case to be met by applicant – clarity – claims are clear – novelty – claims are novel – inventive step – claims are inventive – opposition not successful
Representation: Patent applicant: Anthony Franklin of counsel assisted by Wen Wu of Shelston IP
Opponent:Greg Turner of Spruson & Ferguson
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Patent Application: 2007348559
Title:Electrolytic cells for aluminum having cathode carbon blocks with heterotypic structure
Patent Applicant: NorthEastern University, Shenyang Beiye Metallurgical Technology Co. and NorthEastern University Engineering & Research Institute Co. Ltd
Date of Decision: 1 December 2014
DECISION
The opposition fails on all grounds. Subject to an appeal against this decision the application is to proceed to grant.
I award costs according to Schedule 8 against Rio Tinto Alcan International Limited.
REASONS FOR DECISION
Background
This matter relates to patent application 2007348559 in the name of NorthEastern University, Shenyang Beiye Metallurgical Technology Co. and NorthEastern University Engineering & Research Institute Co. Ltd (the applicant), filed on 17 December 2007 as an application under the Patent Cooperation Treaty. The application claims priority from CN 200710010523.4 which was filed on 2 March 2007.
The request for examination of the patent application was filed on 24 September 2009. As a consequence, substantive amendments of the Patents Act brought about by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 do not apply to the present patent application. This includes the amendment to subsection 60 (3A) that allows the Commissioner to refuse a patent application if satisfied on the balance of probabilities that a ground of opposition exists. I also note that any subsequent reference to subsections of the Patents Act relates to the Patents Act 1990, prior to amendment by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012.
The application was advertised as accepted on 12 May 2011. A notice of opposition to grant of a patent was filed on 12 August 2011 by Rio Tinto Alcan International Limited (the opponent), followed by a statement of grounds and particulars on 14 November 2011.
The applicant filed Section 104 amendments on 19 July 2013, after the evidence in answer had been completed. Leave to amend was granted on 1 November 2013, and the proposed amendments were allowed on 22 January 2014.
The evidence
Evidence consists of:
Evidence in support in the form of a statutory declaration from Hao Zhang (Zhang #1) dated 9 May 2012 and 8 supporting exhibits (HZ1 to HZ8)
Evidence in answer in the form of a statutory declaration from Rebekah Frances Gay (Gay #1) dated 15 July 2013 and 4 supporting exhibits (RFG1 and RFG4)
Evidence in answer in the form of a statutory declaration from Prof. Feng Naixiang (Naixiang #1) dated 15 July 2013
Evidence in reply in the form of a statutory declaration from Hao Zhang (Zhang #2) dated 9 September 2013 and 3 supporting exhibits (HZ9 to HZ11)
Onus
It is well established under the previous legislation that in proceedings such as these before the Commissioner, the onus rests with the opponent to clearly establish its case in reaching a conclusion on any issue. In F. Hoffman-La Roche AG v New England Biolabs Inc [2000] FCA 283, Emmett J of the Federal Court found that in opposition proceedings, the Court (and by implication the Commissioner of Patents in her role as a tribunal) should be "clearly satisfied that the patent, if granted, would not be valid". Where questions of fact such as obviousness and existence of invention are involved "the grant should not be refused unless it has been clearly shown that the grounds of opposition have been clearly made out" (Montecatini v Eastman Kodak (1971) 45 ALJR 593).
Grounds of Opposition
The opponent identified and particularised the following grounds of opposition in the statement of grounds and particulars (SGP):
·Lack of novelty
·Lack of inventive step
·Absence of a manner of manufacture
·Lack of clarity of the claims
·Lack of fair basis in the specification
The SGP also identified subsection 40(2) as a ground but provided no further detail under this subsection. At the hearing the opponent did not press the grounds of manner of manufacture or fair basis.
Opponent’s submissions regarding the pleaded case
In regard to the grounds of novelty, inventive step and subsections 40(2) and (3) raised in the SGP, the applicant has made submissions addressing the way in which the opponent’s case was initially pleaded. The applicant generally submits that these grounds are “in some instances, confused and do not reflect any lawful ground of opposition under the Act”, and that this is “exacerbated by references to [the particulars] of the opposition”. In this regard the applicant suggests “the opposition should be dismissed because no lawful grounds of opposition have been pleaded”. The invocation of relevant grounds in the SGP is as follows:
Ground 1: Section 59(b)
The alleged invention is not a patentable invention because it does not comply with subsections 18(1)(a) or (b) of the Patents Act 1990.
1. The alleged invention, so far as claimed in any claim, was published in Australia before the priority date of that claim;
2. The alleged invention, so far as claimed in any claim, was obvious and did not involve an inventive step, having regard to what was known or used in Australia on or before the priority date of that claim;
3. The alleged invention, so far as claimed in any claim was, before the priority date of that claim, otherwise not novel in Australia; and
…
Ground 2: Section 59(c)
The specification filed in respect of the Opposed Application does not comply with subsection 40(2) and (3) of the Patents Act 1990.
As discussed in Robb Farms Industries v Yazaki Australia [1994] APO 60 (“Robb Farms”) on page 7, the purpose of the SGP is to:
“… give the applicant fair notice of the case to be met, and to define the issues of the opposition. As a consequence, the statement must set out the specific grounds of opposition on which the opponent relies, and the material facts on which each ground of opposition is based (Mobay Corp v The Dow Chemical Co [1992] APO 25; 24 IPR 379).
It is also accepted, as recited in Robb Farms on page 7, that:
“…the substantive issues to be decided at a hearing of an opposition are constrained by the grounds of objection specified in sec 59(1)…”
In relation to the ground of novelty, the applicant discusses how the SGP lists 12 prior art documents. The particulars following this list of 12 documents continue to state that:
“The alleged invention as claimed is not patentable as it is not novel when compared with the prior art base as it existed in Australia before the priority date of the claims of the Opposed Application. The relevant prior art base includes the common general knowledge of a person of ordinary skill in the art and includes, but is not limited [sic] the following:” [followed by a listing of the alleged common general knowledge]
The applicant argues that there is no allegation as to lack of novelty as properly required by subsection 7(1) of the Patents Act, because the only allegation of a lack of novelty is in relation to the particularised common general knowledge. It follows that the applicant suggests there is no lawful ground of opposition pleaded that the applicant can discern, and thus that the opposition under this ground should be dismissed.
The applicant raises a similar argument in relation to the ground of inventive step in that the ground has not been alleged in accordance with subsections 7(2) and (3) of the Patents Act. It appears to me that the following particulars of the SGP are also relevant to the opponent’s ground of inventive step.
“The subject matter of claims 1, 2 and 3 and in particular the above features 1(a) to 1(m), 2(a) to 2(d) and 3(a) comprise matter within the common general knowledge in Australia of the relevant addressee prior to the above priority dates of the claims relating to seal assemblies and pressurised containers. It would have been obvious to the relevant skilled worker to combine that knowledge to produce and work the invention as claimed.
The invention as claimed in claims 1, 2 and 3 does not involve an inventive step when compared with the documents listed at "A" above and in light of the common general knowledge as it existed in the patent area before the priority date of the claims.”
The Commissioner’s power to dismiss and opposition is discretionary under Regulation 5.5(3) of the Patents Regulations (as it stood prior to Raising the Bar). In the present case, evidence was filed in the form of evidence in support, answer and reply, and summaries of submission were filed by the parties before the hearing. The parties’ substantive submissions were heard in regard to the grounds of novelty and inventive step considering both the prior art documents and the alleged common general knowledge. In this light I am not satisfied that it is appropriate to consider dismissal of the opposition. Similar can be said for any direction for the opponent to file further and better particulars. Instead, what is relevant for me to determine is whether the opponent is constrained in their opposition under novelty and inventive step to the particulars identified above. In this regard I have already noted the applicants assertion that the SGP recites allegations of novelty and inventive step that are inconsistent with subsections 7(1),(2) and (3).
I acknowledge the inadequacies of the particulars identified by the applicant. Notwithstanding this, I am satisfied that the opponent’s case is not constrained to these erroneous particulars. The SGP clearly invokes the grounds of novelty and inventive step. The SGP then identifies 12 documents and relevant common general knowledge in particulars that generally assert this information is relevant to the grounds of novelty and inventive step. On this basis I consider that the SGP can be read purposively such that the applicant has been given fair notice that the case to be met includes the particularised prior art and common general knowledge assessed on the basis of subsections 7(1), (2) and (3). The fact that the applicant was able to file relevant evidence and submissions also suggests that the case to be met was sufficiently clear.
There appears to be a reasonable argument for the applicant to have sought further and better particulars at an earlier stage of the opposition proceedings. However it is worth noting that at no stage did the applicant request further and better particulars, nor for that matter did the applicant at any stage seek dismissal. From the submission presented prior to and at the hearing, the applicant appears to have had no trouble in determining the case to be answered in regards to the grounds of novelty and inventive step with particular reference to the requirements of section 7.
I have already determined that the opponent is not bound in this opposition to a literal interpretation of certain particulars which fail to adequately invoke relevant parts of section 7. However, I note that in the event that I found that the opponent’s case was bound by these particulars it appears that it would be appropriate to invoke subsection 60(3) such that I could consider novelty and inventive step in accordance with section 7. Subsection 60(3) of the Patents Act states that:
The Commissioner may, in deciding a case, take into account any ground on which the grant of a standard patent may be opposed, whether relied upon by the opponent or not.
In relation to ground 2 which invokes subsections 40(2) and 40(3), the SGP recites particulars only relating to clarity and fair basis. At the hearing the opponent argued that that the claims did not define the invention, however there is no invocation of a ground under paragraph 40(2)(b) in the SGP. In this regard the opponent has not provided the applicant with any notice of a case to be met under subsection 40(2). As a result I will not consider any grounds under subsection 40(2) as part of this decision.
Further in regard to ground 2, there is the issue that submissions were presented at the hearing by the opponent in regards to the clarity of the claims which have no basis in the SGP. While I note that amendments were made to the claims after the filing of evidence in answer, the opponent should have amendment their SGP to incorporate new objections. Regardless, I consider that these clarity issues warrant discussion. As both parties have made their submissions regarding these issues, I am satisfied that I may address them as part of this decision.
Conclusion: Grounds relevant to the decision
In accordance with my discussion above, the grounds relevant to my decision are novelty, inventive step and subsection 40(3): clarity.
The Specification
The invention described in the specification relates to the field of aluminium (or aluminum) electrolysis, in particular electrolytic cells for producing aluminium through a fused salt electrolysis process.
The specification discusses known methods of producing aluminium by cryolite-aluminia fused salt electrolysis. Pages 1 and 2 of the specification describe a common apparatus and method for producing aluminium via fused salt electrolysis. The known apparatus includes an electrolytic cell lined with carbon materials. Refractory materials and heat insulating bricks are provided between a steel case and the carbon liner of the cell. The carbon liner is generally constructed by laying carbon blocks made of anthracites or graphite materials or compounds thereof. Carbon pastes are then tamped at joints between these carbon blocks. Cathode steel rods are provided at the bottom of the carbon blocks (at the bottom of the electrolytic cell) extending out of the case. The carbon blocks thus form part of the cathode structure. An anode is suspended above the carbon blocks to enable current to be applied to the cell.
In order to convert alumina to aluminium metal the Hall-Héroult process is used. In this process, molten aluminium is provided between the cathode and the anode with a cryolite-alumina electrolyte melt, at a temperature between 940 and 970°C. Molten aluminium is denser than the electrolyte melt, so the molten aluminium sinks to contact the carbon cathode below the electrolyte melt. Further, in operation, the top surface of the molten aluminium is higher than the top surface of the cathode. Thus the molten aluminium effectively forms the active surface of the cathode. This is commonly known as a pooled configuration.
When direct current is provided between the anode and the cathode, the cryolite-alumina electrolyte reacts at the anode and the cathode. Here, oxygen produced from electrolysis of alumina at the anode reacts with carbon on the anode to produce carbon dioxide. An aluminium carrying ion is discharged on the cathode so as to obtain electrons to generate metal aluminium. This cathode reaction occurs on the surface of the molten aluminium within the cell. In this regard, the top surface of the molten aluminium layer functions as the top surface of the cathode of the electrolytic cell.
An important parameter of the operation of such an electrolytic cell is the inter electrode distance (this is commonly referred to as the ACD or anode-cathode distance). This is the distance between the bottom surface of the anode and the top surface of the cathode. The specification indicates that this distance is typically 4-5cm and that it is generally a crucial technical parameter. In this regard a value too high or too low will impact the efficiency of the cell.
In this described pooled configuration, the anode to cathode distance is significantly affected by waves or fluctuations formed in the surface of the molten aluminium. The disturbances occur as a result of electromagnetic forces with the cell, or because of anode gas escaping from the anode. The specification points out that the wave crest heights for these disturbances are typically about 2cm. If no disturbances are present, then it is possible to perform electrolysis at inter electrode distances in the range 2-3cm.
In the background to the invention, the specification also refers to aluminium electrolytic cells operating in a drained mode. Instead of pooling molten aluminium above the cathode blocks, the molten aluminium is formed on the surface of the carbon cathode blocks and is subsequently drained from the cell via channels within the cathode. Such cells, commonly referred to as aerial draining TiB2 cathode electrolytic cells, address the issue of molten aluminium waved at the cathode because the top surface of the molten aluminium is below the top surface of the cathode. However these cells present other problems and disadvantages which make them less desirable for industrial application.
The specification indicates that the present invention aims to solve or alleviate at least one aspect of the disadvantages in association with the current aerial drainage type cell. More specifically, the specification suggests that the present invention aims to solve the problems of large fluctuation of the surface level of cathode molten aluminium with the current industrial aluminium cell, that the inter electrode distance is limited, the cell voltage within the electrolytic cell cannot be further decreased, as well as the poor life span of the electrolytic cell.
The claims
The specification ends in six claims as follows:
1. An aluminum electrolytic cell comprising: a cell case, a carbon anode, a bottom carbon internal lining, and refractory and heat insulating materials provided between the bottom carbon internal lining and the cell case, the bottom carbon internal lining being composed of a plurality of profiled cathode carbon blocks, wherein a longitudinal direction of the cathode carbon block is perpendicular to a longitudinal direction of the cell case,
each cathode carbon block comprising a connecting part at a bottom end and a protruding part at a top end, the connecting part being formed integrally with the protruding part,
the connecting parts of the adjacent cathode carbon blocks being connected by tamping carbon pastes, with grooves extending in the longitudinal direction of the cathode carbon block being formed between the adjacent protruding parts of the adjacent cathode carbon blocks,
each protruding part of the cathode carbon block comprising, in the longitudinal direction of the cathode carbon block, 2-8 protruding sections which are arranged at predetermined intervals to form between adjacent protruding sections a slot extending in the longitudinal direction of the cell case, and
a height of molten aluminum within the electrolytic cell from the upper surfaces of the protruding portions is about 30-200mm after the aluminum is generated.
2. The aluminum electrolytic cell of claim 1, wherein: the protruding portion comprises an upper portion and a lower portion, and in cross section perpendicular to the longitudinal direction of the cathode carbon block, the width of the lower portion is larger than the width of the upper portion.
3. The aluminum electrolytic cell of claim 1, wherein the recesses between the lower portions of the adjacent protruding portions of the adjacent cathode carbon blocks are filled with pelletized bumps or powders made from over 30-70% of powdery alumina and 70%-30% of powdery cryolite.
4. The aluminum electrolytic cell of claim 1 or claim 2 wherein: the protruding part of the cathode carbon block has an upper step and a lower step with, in cross section, the width of the lower step being larger than the width of the upper step.
5. An aluminum electrolytic cell substantially as herein described with reference to Figures 1 and 2, 3 and 4, 5, and 7, 7 to 9, or 10 to 12.
6. A method of producing aluminum in an aluminum electrolytic cell of any of claims 1 to 4.
Claim 1 is best understood with reference to figures of the specification. In this regard, figures 7 and 8 are provided below with further annotations to assist in identifying features.
Figure 7
Figure 8
Figures 7 and 8 show an aluminium electrolytic cell as defined by claim 1 with a steel cell case (1), a bottom internal carbon lining composed of a plurality of profiled cathode carbon blocks (4), with refractory and heat insulating bricks (3) provided between the bottom internal carbon lining and the cell case. Figure 7 depicts a view of the cell in which the carbon blocks are viewed end on. Here the longitudinal direction of the cathode carbon blocks (4), shown in figure 8, is perpendicular to a longitudinal direction of the cell case. While not shown in the figures, in operation a carbon anode(s) would be suspended above the cathode carbon blocks.
Each cathode carbon block (4) has a bottom end which connects to other cathode carbon blocks via tamping paste (6), and a protruding part at the top end (denoted by item B). The figures show the protruding part (B) is integral to the remainder of a carbon block. Grooves which extend in the longitudinal direction of the cathode carbon blocks are formed between adjacent protruding parts of adjacent cathode carbon blocks. These grooves are depicted within the circle denoted A in figure 7 as the area directly above the tamping paste 6.
Each protruding part (B) of a cathode carbon block comprises in the longitudinal direction of the cathode carbon block, 2-8 protruding sections arranged at predetermined intervals (see figure 8 where the protruding part (B) is divided into two protruding sections). The two protruding sections of item B form a slot there between (depicted in figure 8) extending in the longitudinal direction of the cell case.
A height of molten aluminium within the electrolytic cell from the upper surfaces of the protruding portions is about 30-200mm after the aluminium is generated.
There was some discussion at the hearing in regards to the meaning of this feature.
While the rules of construction for an Australian patent specification are well summarized in Decor Corp v Dart Industries 13 IPR 385, recently, the correct application of these rules to the construction of claims was discussed by Bennett J in H Lundbeck A/S v Alphapharm Pty Ltd [2009] FCAFC 70; 81 IPR 228 at [118] – [120]:
"the words in a claim should be read through the eyes of the skilled addressee in the context in which they appear ... while the claims define the monopoly claimed in the words of the patentee's choosing, the specification should be read as a whole ... it is not permissible to read into a claim an additional integer or limitation to vary or qualify the claim by reference to the body of the specification ... terms in the claim which are unclear may be defined or clarified by reference to the body of the specification"
Also relevant to the application of the rules of construction are the comments made by Middleton J in Eli Lilly and Company Limited v Apotex Pty Ltd [2013] FCA 214, 100 IPR 451 at [139]:
"It is well settled that the Court should, from the outset, approach the task of patent construction with a generous measure of common sense. The Court must place itself in the position of a person skilled in the relevant art, being the subject matter of the patent. From this perspective, the patent is to be read as a whole, in the context of the specification and in light of the prevailing common general knowledge and state of the relevant art at the priority date."
I first note that there is no antecedent to the term “the protruding portions”. It appears as if this term could refer to either the protruding “parts” or the protruding “sections”. Neither party applied a particular preference to the construction of this term. The specification contains numerous references to “portions” in the context that each carbon block includes a plurality of “protruding portions”. For example: page 6 where it is stated that “the electrolytic cell built by such profiled cathode carbon blocks having protruding portions…”; “In an example, each cathode block has 2 protruding portions…”; and, page 9 which describes cathode carbon blocks whereby “each of which the upper surface includes protruding portions”. In this regard I am satisfied that it is clear that the term “protruding portions” should be equated with the term “protruding sections”. For the remainder of this decision I will use the term “protruding portions” in place of “protruding sections”.
At the hearing, the opponent presented two particular submissions in regard to the construction of the feature defining the height of molten aluminium after the aluminium is generated. First, the opponent submitted that claim 1 is not restricted to a drained or pooled configuration. Secondly, the opponent submitted that the term “height of molten aluminium” included within its scope the possibility that molten aluminium did not extend down into grooves/slots between protrusions of the cathode. Instead, the opponent submitted that claim 1 included within its scope, the presence of a molten aluminium layer floating above some other liquid layer. I will address this second submission first.
In operation of a common aluminium electrolytic cell, as pointed out in the specification at page 1, molten aluminium and cryolite-alumina electrolyte melt having a temperature between 940-970°C is provided between the carbon cathode and the carbon anode of the cell. The density of molten aluminium is larger than that of the electrolyte melt. This means that the molten aluminium sinks due to gravity and is contacted with the carbon cathode below the electrolyte melt. In other words, the molten aluminium forms a layer sitting directly upon the carbon cathode.
Furthermore, page 7 discusses the molten aluminium level in the context of parameters of the electrolytic cell. Here it is stated:
“The molten aluminum level within the electrolytic cell calculated from the upper surfaces of the walls protruded from the surface of the cell bottom is about 3-20 cm, the cell voltage is about 3.0-4.5 v, the level of the electrolyte above the molten aluminum is about 15-25 cm, the inter electrode distance of the electrolytic cell is about 2.5-5.0 cm, the electrolyte temperature is about 935-975° C., the molecular ratio of the electrolyte is about 2.0-28, the concentration of alumina is about 1.5-5%.” (my emphasis)
Considering the specification as a whole I am satisfied that it is only reasonable to construe the height of molten aluminium from the upper surfaces of the protruding portions after the aluminium is generated, as defining a layer which entirely covers and directly contacts the carbon cathode. I note that the applicant submitted that the term should be construed as such. Further, I also note that there does not appear to be basis within the specification for the construction adopted by the opponent, nor is there any evidence from the opponent suggesting that a person skilled in the art would adopt the construction suggested in the opponent’s submissions.
Having found that the feature defines a layer which entirely covers and contacts the carbon cathode after the aluminium is generated it must follow that claim 1 is directed towards an aluminium electrolytic cell operated in pooled mode. As I discussed earlier, in pooled mode, the top surface of the molten aluminium layer functions as the top surface of the cathode of the electrolytic cell. If the electrolytic cell of claim 1 included within its scope, a layer of aluminium generated in drained mode, then there would be no height of molten aluminium from the upper surfaces of the protruding portions. This is because a cell in drained mode operates by way of molten aluminium forming on the cathode, and subsequently draining, via gravity, into grooves/slots between protrusions of the cathode.
Further construction issues relating to the claims will be discussed under the ground of clarity.
Subsection 40(3): Clarity
Claim 3
“the recesses”
The opponent submitted that claim 3, which is dependent upon claim 1, is not clear. It was submitted that there is no antecedent to the term “the recesses” as claim 1 does not contain any “recesses”. In this regard the opponent suggests that the recesses referred to may be the “grooves” or the “slots” in claim 1, or alternatively another undefined feature. In response the applicant submits that a recess is by definition, “a space that is set back or recedes” and that:
“Claim 1 has cathode carbon blocks with 2-8 protruding sections arranged at predetermined intervals. In the transverse direction (the longitudinal direction of the cathode carbon block) there are “grooves” between the adjacent protruding parts. In the longitudinal direction of the cell case there is, between adjacent protruding sections, a “slot”. Although, in claim 1, the word “recesses” is not used in relation to the grooves and slots it is abundantly clear that these are, between adjacent protruding sections, recesses. It is submitted that there is no ambiguity in the language, but reference to the body of the specification makes it clear that the spaces that are between the adjacent protruding sections are those referred to in claim 1, in transverse direction referred to as “grooves” and in the longitudinal direction referred to as “slots”. These are properly referred to as recesses and there is no ambiguity when claim 3 uses that word.”
I am not satisfied that either of these approaches is correct. I refer to the feature as defined in claim 3. Claim 3 is directed to the aluminium electrolytic cell of claim 1, wherein the recesses between the lower portions of the adjacent protruding portions of the adjacent cathode carbon blocks are filled with pelletized bumps or powders made from over 30-70% of powdery alumina and 70%-30% of powdery cryolite. I first note that there is no explicit antecedent to the term “lower portions” to be found in claim 1. I also emphasise that “the recesses” are between the lower portions of the adjacent protruding portions of the adjacent cathode carbon blocks.
It is clear from the relevant case law that construction of such potential ambiguity is to be performed by the person skilled in the art reading the specification as a whole. In this regard, reference to the figures of the specification assist in understanding the scope of this feature of claim 3.
With particular regard to figure 7, I point out that there are 7 cathode carbon blocks depicted in the figure. Reference to the recesses between the lower portions of the adjacent protruding portions of the adjacent cathode carbon blocks should be interpreted as a reference to the grooves formed between adjacent cathode carbon blocks, as identified with the circle denoted A. Here there is clearly a recess (groove) between the lower portions of adjacent protruding portions (the 2-8 elements of item B) of adjacent cathode carbon blocks (items 4). With reference to figure 8, the slot which divides the protruding portions of the individual carbon blocks is not between adjacent cathode carbon blocks. In this regard there is no confusion as that identified by the opponent. Furthermore, “the recesses” of claim 3 does not include the “slots” as discussed in the applicant’s submissions. I am satisfied that the person skilled in the art, reading the specification as a whole would not arrive at an alternative construction of this feature.
This construction is also consistent with the remainder of the claim and the purpose of the powdery alumina and powdery cryolite. In this regard, the specification at page 12 states:
“Pelletized bumps or powders made from over 30-70% of powdery alumina and 70%-30% of powdery cryolite are filled between the lower portion of walls protruded from the bottom surface of the aluminum electrolytic cell having profiled cathode carbon blocks, such pelletized bumps or powders are under the electrolytic temperature, when the cryolite therein is molten, the molten cryolite is formed into a kind of precipitate on the cell bottom to seal the cracks and gaps so as to prevent the molten aluminum from entering into the cell bottom to melt the cathode steel rod and damage the electrolytic cell.”
The above information discusses that bumps or powders of powdery alumina and cryolite are placed at the cell bottom to seal cracks and gaps and to prevent molten aluminium from entering into the cell bottom to cause damage. In this regard, the relevant “recess” of claim 1 must be the grooves between adjacent cathode carbon blocks. The figures, including figures 7 and 8, show that these grooves form part of the bottom surface of the cell and include potential cracks and gaps which form in the vicinity of tamping paste 6. There are no potential cracks and gaps in the “slots” of claim 1.
Powdery alumina, powdery cryolite, and molten aluminium
Claim 3 includes the feature wherein recesses are filled with bumps or powders made from [powdery alumina and powdery cryolite]. The opponent submitted that claim 3 is also not clear as follows:
“A further uncertainty is the pelletized "powdery alumina" and "powdery cryolite" located in the recesses as defined in claim 3. Claim 1 defines the cell as including molten aluminium, of a particular depth above the protruding portions. The particular issue is that claim 3 defines a device not a method. You cannot have both "powdered alumina" and "powdery cryolite", and the "molten aluminium" at the same time at the same location.”
The opponent submitted that this also impacts upon the construction of claim 1 as follows:
“If claim 1 is broad enough to have within its scope "powdery alumina" and "powdery cryolite" (as claim 3 is appended to claim 1) then claim 1 lacks clarity since you cannot have "molten aluminium" and "powdery alumina", and "powdery cryolite" at the same time.”
The applicant responded by suggesting that:
“In constructing an aluminium electrolytic cell according to claim 3 it will be known that the recesses must be filled with the pelletized bumps or powders comprised as claimed. That is a clear requirement or integer of the claim. The fact that, when the electrolytic cell is in use, the pelletized bumps are caused to melt does not render the claim ambiguous. The operation of the device, which in claim 3 has pelletized bumps or powders filling the recesses, is explained at step 4 on page 12 of the specification.”
I again refer to the specification at page 12 which discusses the use of powders for the purpose of sealing cracks and gaps. Here it is stated that:
“Pelletized bumps or powders made from over 30-70% of powdery alumina and 70%-30% of powdery cryolite are filled between the lower portion of walls protruded from the bottom surface of the aluminum electrolytic cell having profiled cathode carbon blocks, such pelletized bumps or powders are under the electrolytic temperature, when the cryolite therein is molten, the molten cryolite is formed into a kind of precipitate on the cell bottom to seal the cracks and gaps so as to prevent the molten aluminum from entering into the cell bottom to melt the cathode steel rod and damage the electrolytic cell.” (my emphasis)
With this in mind, the person skilled in the art would readily understand that it is not possible to have the pelletized bumps and powders existing at the same time as the molten aluminium after the generation of molten aluminium. These materials have a lower temperature than that at which electrolysis occurs. Thus the materials must melt to fill the gaps before molten aluminium is generated by electrolysis.
I consider claim 3 is limited to the presence of molten aluminium because the claim is directed to the cell of claim 1, and because the reason for inclusion of the powdery material is to melt to seal cracks and gaps from molten aluminium. Taking this approach it is clear that a literal construction of claim 3, whereby recesses are filled with these materials, is not possible. However, I consider that a person skilled in the art would have no problem resolving this ambiguity. The person skilled in the art would purposively consider that prior to the generation of molten aluminium within the cell, the recesses of claim 3 were filled with the powdery material, as opposed to are filled in the presence of molten aluminium.
Therefore I find that the claims are clear.
Novelty
For the purposes subsection 7(1) of the Patents Act, an invention is to be taken to be novel when compared with the prior art base unless it is not novel in the light of prior art information within the prior art base. It is well established that the general test for anticipation is the reverse infringement test. The classic formulation of this test is that given by Aickin J in Meyers Taylor Pty Ltd v Vicarr Industries Ltd [1977] HCA 19 at [20]; [1977] HCA 19; 137 CLR 228 at 235:
“The basic test for anticipation or want of novelty is the same as that for infringement and generally one can properly ask oneself whether the alleged anticipation would, if the patent were valid, constitute an infringement.”
This test is satisfied if the alleged anticipation discloses all of the essential features of the invention as claimed (Nicaro Holdings Pty Ltd v Martin Engineering Co [1990] FCA 40 at [19]; [1990] FCA 40; 16 IPR 545 at 549). To meet this requirement, the prior art must contain “clear and unmistakable directions to do what the patentee claims to have invented” (The General Tire & Rubber Company v The Firestone Tyre and Rubber Company Limited [1972] RPC 457 at 486).
Regarding the requirement of a clear and unmistakable direction, Australian courts have often cited with approval the words of the UK Court of Appeal in The General Tire case which states at pages 485-486:
"If ... the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee's claim, but would be at least be as likely to be carried out in a way that would not do so, the patentee's claim will not be anticipated…
To anticipate the patentee's claim, the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented ... A signpost, however clear, upon the road to the patentee's invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee…”
I also note that an alleged anticipation need not explicitly disclose all of the essential features of the claimed invention. In this regard, a disclosure may be implicit as discussed in Bristol-Myers Squibb Company v FH Faulding & Co Ltd [2000] FCA 316; 46 IPR 553 at 576:
“What all authorities contemplate, in our view, is that a prior publication, if it is to destroy novelty, must give a direction or make a recommendation or suggestion which will result, if the skilled reader follows it, in the claimed invention. A direction, recommendation or suggestion may often, of course, be implicit in what is described and commonly the only question may be whether the publication describes with sufficient clarity the claimed invention or, in the case of a combination, each integer of it.”
Similarly, the Full Court in H Lundbeck A/S v Alphapharm Pty Ltd [2009] FCAFC 70 at 181 said (citing Nicaro Holdings Pty Ltd v Martin Engineering Co [1990] FCA 40):
“If the prior art discloses some but not all integers of a claimed patent to a product, such as a combination, there is anticipation if the skilled addressee would add the missing information as a matter of course and without the application of inventive ingenuity or undue experimentation.”
The following documents were pressed by the opponent in its submissions as depriving the claimed invention of novelty:
· D1: US 5330631 A (Juric et al.) 19 July 1994
· D2: AU 1995/031901 B (Moltech Invent S.A.) 27 March 1996
Document D1: US 5330631
The opponent suggests that document D1 (provided as exhibit HZ2) discloses all of the features of claim 1. In particular, the opponent identifies figure 5 of the document which discloses an aluminium smelting cell comprising side walls and a floor defining a cathode surface and at least one anode spaced apart and substantially parallel to the cathode surface to define an inter electrode gap. Column 6 lines 14-33 discuss that the cathode is formed with two rectangular arrays of pairs of rectangular projections. These two arrays are positioned either side of a central collection channel with projections separated by channels which allow pools of metal to collect. At least the horizontal surfaces of the projections are covered by a suitable wetted cathode material. The summary of the invention in column 2 lines 47-68 discusses that the cells forming the various embodiments of D1 may operate from fully drained mode up to a depth of 10cm or more depending on the height of the projections.
The applicant argues that a number of features of claim 1 are not disclosed in the document. In this regard, I will proceed on the basis that the features not identified by the applicant are disclosed in the document. The applicant argues that there is no disclosure in document D1 of the following features:
· The bottom carbon internal lining of the aluminium electrolytic cell being composed of a plurality of profiled cathode carbon blocks. It would thus follow that the document would not disclose: a longitudinal direction of the cathode carbon blocks is perpendicular to a longitudinal direction of the cell; each cathode carbon block comprising a connecting part at a bottom end and a protruding part at a top end, the connecting part being formed integrally with the protruding part; tamping paste connecting the carbon blocks; and, grooves between adjacent carbon blocks.
· The height of molten aluminium within the electrolytic cell from the upper surface of protruding sections being about 30-200mm after the aluminium is generated.
The bottom carbon internal lining of the aluminium electrolytic cell being composed of a plurality of profiled cathode carbon blocks.
The opponent first points to Zhang #2 in which their expert discusses his interpretation of the electrolytic cell of figure 5, provided as exhibit HZ10 (reproduced over the page). The opponent argues that the electrolytic cell is not a monolithic cathode but uses carbon blocks. In this regard, exhibit HZ10 is annotated by the opponent with the item “Z”. Zhang #2 at [7] identifies these lines “Z” as showing a construction in the form of carbon blocks joined by tamping paste. There are similar lines identified by the opponent in figure 7 of D1 provided as exhibit HZ11. The opponent also submitted that document D1 contains reference to carbon blocks in regard to the phrase at column 6 lines 41-44 where it is stated that:
“In each case, the slot was 80 mm deep in a TiB2 composite approximately 100 mm deep over a cathode block approximately 220 mm deep”.
In relation to the identification of lines Z it is important to note there is no description of the function or purpose of these lines. The only reference to these lines in the description is with reference to figure 7 in discussing that dotted lines simply equate with triangular protrusions (document D1 at column 7, lines 42-55). Furthermore, the lines identified in figure 5 are not located at particular intervals to suggest uniform division of the cathode into a series of blocks. While the phrase “cathode block” appears once in the description, there is no further reference to blocks, or for that matter, any particular discussion of the construction of the cathode as being monolithic or formed of a plurality of blocks. I must therefore conclude that there is no direction in the specification to the feature of a plurality of carbon blocks.
The opponent also ran a line of argument that the feature was to be considered implicitly disclosed in D1. For an implicit anticipation, it is required that the skilled addressee would add the missing information as a matter of course. In this regard, a range of evidence was cited. The opponent referred to their expert’s declaration Zhang #2 at [7] which states that by 1990 monolithic cathodes were “long obsolete” and that “there is no doubt that the cell of [D1] had cathode blocks and was not a monolithic structure as cell development had moved to blocks by 1990”. The opponent cited exhibit RFG2 which is an article entitled “Introduction to Aluminium Electrolysis” edited in 1993 where it is stated at p128:
“Up to the last 10 to 25 years, monolithic linings were commonly used. However by increasing cell size and requirement of more consistent properties of linings, the advantage of superior physic-chemical properties and precisely machined prebaked blocks has become increasingly important”.
Further to the above, the opponent submits that Mr Hao Zhang worked at the Bell Bay Tasmania plant where electrolytic cells according to Exhibit HZ2 (document D1) were used. At [7] of Zhang #2, Mr Zhang states that the cells at Bell Bay were "composed of a plurality of carbon blocks with tamping carbon paste located between the blocks" and that “[Bell Bay] ceased using monolithic cathodes by the late 1970s”.
As a final point, the opponent points to the evidence of the applicant’s expert in Naixiang #1, in particular paragraph [22] where Prof Naixiang discusses document D1.
“US patent no. 5,330,631 describes a cell design which incorporates protrusions formed in the surface of the cathode. The channels between each protrusion run in the same longitudinal direction as the electrolytic cell. I have depicted below two examples of such a configuration below.”
This paragraph is followed by two figures showing examples of individual profiled carbon blocks which incorporate protrusions described in D1. On this basis, it appears that the opponent argues that the applicant’s own evidence suggests that D1 is to be read as implicitly disclosing a plurality of carbon blocks.
I first note that the statement of the opponent’s expert that monolithic cathodes were long obsolete at the priority date of Document D1 does not appear to be supported by the cited evidence RFG2. RFG2 merely suggests that up until recent years (the last 10 to 25 years) monolithic cathodes were commonly used, and that the use of carbon blocks has become more prevalent. This does not amount to evidence that monolithic cathodes were no longer used. Further the applicant’s expert in Naixiang #1 states at [26a] that:
“Monolithic cathodes have been used, and were commonly in use before 1994, being the date of US 5,330,631. In the absence of any discussion regarding cathode carbon blocks, I understand US 5,330,631 to be describing a cell that has a monolithic cathode.”
While the opponent attests to exclusive use of carbon blocks in the art, I am not satisfied that the evidence establishes that the skilled addressee would as a matter of course, consider the cathode of D1 to be constructed of a plurality of blocks. The evidence of RFG2 and Naixiang #1 suggests that a person skilled in the art could reasonably consider monolithic cathodes to be still in use at the relevant date of D1. The fact that the invention of document D1 may have been implemented at Bell Bay using carbon blocks does not add to the disclosure of D1.
As a final note, I refer to the argument that applicant’s own evidence suggests that D1 is to be read as implicitly disclosing carbon blocks. I see no basis for this assertion. This particular evidence appears to merely describe features disclosed in D1 in context of the applicant’s invention, which itself relates to a plurality of carbon blocks.
Thus I am satisfied that document D1 does not disclose the feature of a plurality of profiled cathode carbon blocks.
The height of molten aluminium within the electrolytic cell from the upper surface of protruding portions being about 30-200mm after the aluminium is generated.
The opponent raises a number of points in regard to the height of molten aluminium within the electrolytic cell after generation. First, the opponent points to evidence of Zhang #1 at [6] which discusses the common general knowledge for molten aluminium heights above cathode carbon blocks, in the context of pooled cell configurations:
“The depth of molten aluminium above the carbon blocks ranged between 0 and 400mm. However typically the depth was between 100 and 250mm, with the depth varying depending on how frequently and when the molten aluminium was tapped from the electrolytic cell. This depth of molten aluminium was part of the common general knowledge in Australia in the industry of aluminium smelting prior to 2007.”
The opponent also points to the description of document D1 which states between column 2 line 47 and column 3 line 5 that:
“The metal level in the substantially flat cathode regions may vary from the fully drained mode up to a depth of 10 cm or more depending on the height of the shaped structures. To gain the full benefit from the new cell design, the depth should not exceed that of the shaped structures for an extended time period…
The metal level may be allowed to rise above the level of the shaped structures for limited time periods after anode profiling has occurred, and in certain circumstances this can be additionally advantageous…
The new cell design therefore allows flexibility of cell operation as either:
(a) thin film wetted cathode (horizontally drained); or
(b) thick film (pool) wetted cathode (horizontal undrained).”
The applicant submitted in response that:
“… the basis of the invention in Juric is that the pool of aluminium should collect between the projections leaving the shaped projections exposed so that the anode can be shaped correspondingly. It is expressly stated that the depth above the top of the projections should not be maintained for a prolonged period otherwise the anode profiling will be lost. The whole purpose of the invention is to result in anode profiling to enhance bubble release. Even if it could be said that, when the depth of aluminium is above the top of the projections this reads onto the relevant part of claim 1 of the oppose Application, this is not what is intended and, in the words of General Tire, the method described in Juric “would be at least as likely to be carried out in a way which would not ...” infringe claim 1.”
I am inclined to agree with the applicant that there is no clear and unmistakable direction to the operation of the invention of document D1 in pooled mode, in a range of depth/height of 30-200mm. The specification merely states that the invention may operate in a pooled mode by means of allowing the molten aluminium to rise above the shaped structures (protrusions) for limited time periods. While a depth of aluminium is provided as being up to 10cm, this does not refer to a depth/height above the shaped structures. This depth is simply the distance from the bottom of the cell to the top level of the molten aluminium with the general purpose of the invention being to maintain the molten aluminium below the level of the shaped protrusions.
While it is possible that the skilled addressee may use this teaching to operate the cell of D1 using a height of 30-200 mm above the shaped structures, I consider it at least equally likely that the skilled addressee is lead to operate the invention outside of this range. The fact that it was common general knowledge to operate an electrolytic cell at depths/heights within the range defined in the claims does not add to the disclosure of D1. Document D1 contains no discussion of any particular depth of molten aluminium above the shaped protrusions and as such, it has not been clearly shown that the prior inventor has “planted his flag” within the precise range.
Conclusion
In accordance with my discussion above I find claim 1 novel in view of document D1. Claims 2-6 add further features to those defined in claim 1 and are thus also considered novel in view of D1.
D2: AU 1995/031901
The opponent suggests that document D2 (provided as exhibit HZ3) discloses all of the features of claim 1. Document D2 (at page 6 lines 10-21) describes an improved aluminium electrolytic cell comprised of cathode carbon blocks whereby wave movement in the layer of molten aluminium is restrained in either the pool or layer (when operating in drained mode) of molten aluminium by means of a series of parallel channels or grooves in the top surfaces of the carbon blocks, along the longitudinal direction of the carbon blocks. The specification generally discusses that the embodied cells may operate in pooled or drained mode. In this regard document D2 states between page 6 lines 28 and page 7 line 29 that:
“The surfaces of the carbon blocks making up the cathode cell bottom may be covered by a layer of molten aluminium forming a drained cathode surface, the channels or grooves forming a canal serving to guide the flow of aluminium across the cell. In this drained configuration, the channels or grooves are partly filled with molten aluminium and the electrolysis takes place between the aluminium-wetted cathode and the facing anode surface…
Alternatively, the surfaces of the carbon blocks making up the cathode cell bottom are covered by a pool of molten aluminium, the channels or grooves serving to reduce motion of the aluminium making up this pool…
In either case, for the drained configuration or when there is a pool of aluminium, the inter-electrode distance is reduced with a concomitant reduction of cell voltage and an increase in energy efficiency.
In all cases, for drained configurations and when there is a pool of aluminium, the channels are so configured and arranged, in particular as regards their depth and the shape and angle of their walls, that the molten aluminium contained in the channels is restrained from movement in the longitudinal direction of the cell…”
In response the applicant has argued that particular features of claim 1 are not disclosed in D2. As with document D1, I will proceed on the basis that the features not identified by the applicant are disclosed in the document. The applicant asserts as follows:
· That there is no disclosure in D2 of a height of molten aluminium within the electrolytic cell from the upper surface of protruding sections being about 30-200mm after the aluminium is generated.
· Document D2 does not disclose the electrolytic cell of claim 1 wherein the cathode carbon blocks have 2-8 protruding portions arranged at predetermined intervals. It would thus follow that the document would not disclose a slot extending in the longitudinal direction of the cell case.
The height of molten aluminium within the electrolytic cell from the upper surface of protruding portions being about 30-200mm after the aluminium is generated.
The opponent’s assertion as to the disclosure of this feature relies upon figure 3 (provided as exhibit HZ7) of document D2. Figure 3 is a cross-sectional schematic depiction of an aluminium electrolytic cell comprising a plurality of cathode carbon blocks (10) connected together via ramming paste (14). The figure shows molten aluminium at a height above the upper surfaces of protruding portions forming a pool of aluminium (40) and a series of parallel channels or grooves (25) in the longitudinal direction of the carbon blocks. Neither the figure itself nor the description discusses the depth/height of this pool of molten aluminium. The opponent relies on the evidence of their expert to suggest that figure 3 discloses a depth of 40-80 mm. In this regard Zhang #1 states at [14]:
“Exhibit HZ7 shows the molten aluminium spaced above the protruding portions of the carbon blocks. As mentioned previously, typically the width of paste between the blocks is in the vicinity of 30mm to 50mm. Although Exhibit HZ7 is a schematic diagram, it provides me with sufficient information, given the thickness of the paste illustrated, to conclude that the height of the aluminium pool 40 above the tops of the protruding parts is 40mm to 80mm.”
As stated by Aldous J in Vax Appliances Ltd v Hoover Plc [1991] FSR 307 at 313 and which was quoted with approval by the Full Federal Court in Leonardis v Sartas No 1 Pty Ltd and Another (1996) 35 IPR 23:
"…patent drawings are not designed to be used to denote precise measurements unless so stated. They are there to illustrate the concept and the overall relationship of the parts."
Without a written disclosure to support the opponent’s contention, I cannot be satisfied that the depth of the pool of molten aluminium depicted in figure 3 is within the range defined in claim 1. Thus document D2 does not provide clear and unmistakable direction to the claimed feature. The fact that operation of a cell in pooled mode within the claimed range may be common general knowledge does not remedy the disclosure of D2.
The cathode carbon blocks have 2-8 protruding portions arranged at predetermined intervals
In regard to the disclosure of 2-8 protruding portions, the opponent points to pages 19 and 20 of document D2 which discuss an embodiment of the invention whereby the cell is discussed as operating in drained mode. In particular I note that the cell of figure 6 (provided as exhibit HZ8) comprises cross-bevels/cross-channels (29) perpendicular to the parallel channels or grooves (20) for draining off product aluminium to maintain the aluminium in the grooves at a constant levels. In particular, page 20 lines 14-18 discloses that:
“Such cross-channels can be formed in one or both ends of the blocks and, if required, one or more intermediate cross channels can be formed by machining grooves across the blocks 10, intersecting with the V or U-shaped grooves formed by bevels 20.”
Furthermore, the opponent submits that:
“As acknowledged in paragraph 31 of the Declaration by Professor Feng Naixiang, the electrolytic cell of Exhibit HZ3 can operate "regardless of whether the cell is a drainage configuration or whether there is a pool of aluminium". As examples, the electrolytic cell as described with reference to Figures 4 to 8, operates as a drained cathode cell, while the electrolytic cell described with reference to Figures 1 to 3 operates as a conventional cell. However the cells can be switched from one mode to the other. For example see page 6, line 28 to page 7, line 18. The invention of HZ3 is described as having "a layer of molten aluminium forming a drained cathode surface" and an "alternative" in which the "surfaces of the carbon block making up the cathode cell bottom are covered by a pool of molten aluminium”.
I consider it clear that the disclosure in relation to figure 6 directs the skilled addressee to a feature whereby a plurality of protruding portions are provided at predetermined intervals forming slots which are perpendicular to the channels formed in the longitudinal direction of the cathode carbon blocks. However it is important to note that this disclosure is in the context of a drained configuration, whereby the height of molten aluminium after the generation of aluminium is below the upper surface of the protrusions. The opponent attempts to rectify this disclosure by referring to different parts of the D2 which discuss embodiments as alternatively operating in drained or pooled (see the extract of document D2 provided above at [82]).
As discussed by the opponent, the embodiments of figures 1 to 3 operate as a pooled cell while figures 4 to 8 represent drained configurations. In relation to the potential operation of the embodied cells as switching between these modes, I consider the document is silent. At no stage does the specification discuss switching the operation of an embodiment from drained to pooled mode (or vice versa). More specifically there is simply no direction that the embodiment of figure 6 should operate in a pooled mode. The text between page 6 line 28 and page 7 line 29 appears to do nothing more than suggest embodiment of the invention (the invention being channels formed in the longitudinal direction of the cathode carbon blocks for restricting movement of molten aluminium) in alternative modes of operation. This does not amount to a suggestion to switch between modes in a particular embodiment.
The opponent also submits that the applicant’s evidence acknowledges the operation of the embodiments in both pooled and drained mode. In this regard, the evidence in answer of the applicant being Naixiang #1 discusses pages 6 and 7 of document D2 stating at [31]:
“Regardless of whether the cell is a drainage configuration or whether there is a pool of aluminium, AU 68809 states that:
…the channels are so configured and arranged, in particular as regards their depth and shape and angle of their walls, that the molten aluminium contained in the channels is restrained from movement in the longitudinal direction of the cell. For a drained configuration, the aluminium can flow along the channel into a collection channel; for a pool configuration, the walls of the channel oppose motion of the aluminium, restraining the pool and reducing turbulence.”
Similarly, I consider this reference is nothing more than a statement that the presence of channels in the longitudinal direction of the blocks serves to restrain movement of the molten aluminium, in either pooled or drained mode operation. This does not demonstrate that the documents D2 directs the addressee to operate its embodiments in a manner which switches between pooled and drained modes. In fact, as pointed out by the applicant, the purpose of the cross-channels in figure 6 is for draining of the product aluminium to maintain molten aluminium within the parallel channels at a constant level. This disclosure teaches away from the operation of the embodiment of figure 6 in a pooled mode.
Therefore I find that document D2 does not disclose that feature, as required by claim 1, whereby an electrolytic cell with a height of molten aluminium above the protruding portions after the generation of aluminium, comprises cathode carbon blocks which have 2-8 protruding portions arranged at predetermined intervals.
Conclusion
In accordance with my discussion above I find claim 1 novel in view of document D2. Claims 2-6 add further features to those defined in claim 1 and are thus also considered novel in view of D2.
Inventive Step
The test for obviousness was provided by Justice Aicken in Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd [1981] HCA 12 at [45]; 148 CLR 262 at 286 as follows:
“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 High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd [2002] HCA 59 at [51]- [53]; 212 CLR 411 at [51]-[53] approved this approach, in addition to that taken in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd [1970] RPC 157 at 187 in which Graham J had posed the question:
“Would the notional research group at the relevant date in all the circumstances directly be led as a matter of course to try [the claimed invention] in the expectation that it might well produce a useful [desired result]?”
Where the invention lies in a combination of features, the question is whether the combination, not each individual feature, is obvious when compared to the prior art base (Alphapharm [2002] HCA 59 at [41]; 212 CLR 411 at [41]; Minnesota Mining & Manufacturing Co v Beiersdorf (Australia) Ltd [1980] HCA 9 at [116]; (1980) 144 CLR 253 at 293).
The usual approach to determining inventive step is the problem-solution approach. Once the problem has been formulated and the common general knowledge and the prior art base has been determined, the question of whether the claimed solution is obvious must be addressed.
In determining the problem or ‘starting point’ for considering inventive step, I am mindful of the words of the majority of the Full Court in AstraZeneca AB v Apotex Pty Ltd [2014] FCAFC 99 at [202]-[203] as follows:
“If the problem addressed by a patent specification is itself common general knowledge, or if knowledge of the problem is s 7(3) information, then such knowledge or information will be attributed to the hypothetical person skilled in the art for the purpose of assessing obviousness. But if the problem cannot be attributed to the hypothetical person skilled in the art in either of these ways then it is not permissible to attribute a knowledge of the problem on the basis of the inventor’s “starting point” such as might be gleaned from a reading of the complete specification as a whole.”
The problem
100.Earlier in my decision, at [22] – [26], I summarised aspects of the background to the invention in relation to the operation of common aluminium electrolytic cells in pooled mode. For such cells, it is clear that an important parameter of operation is the inter electrode distance. This inter electrode distance is largely affected by waves or fluctuations formed in the surface of the pool of molten aluminium. After discussing this particular problem, the specification points to the alternative, drained mode of operation of an aluminium electrolytic cell. The specification discusses that this type of cell addresses the issue of molten aluminium waved at the cathode, but also points out that these cells present other problems and disadvantages. The specification then discusses (at page 5) another problem with aluminium electrolytic cells being the leaking of molten aluminium through cracks formed in the bonding between carbon blocks.
101.The specification continues to state (at page 5) that the present invention aims to solve or alleviate at least one aspect of the disadvantages in association with the current aerial drainage type cell. More specifically, the specification suggests that the present invention aims to solve the problems: of large fluctuation of the surface level of cathode molten aluminium with the current industrial aluminium cell; that the inter electrode distance is limited and the cell voltage within the electrolytic cell cannot be further decreased; as well as the poor life span of the electrolytic cell.
102.I now turn to independent claim 1. I consider it clear that this claim is directed to solving the problem of waves/fluctuations in the surface level of the molten aluminium in an electrolytic cell in pooled configuration. In this regard I refer to the applicant’s evidence at [36] of Naixiang #1, which discusses how the 2-8 protruding portions address this particular problem.
“…my configuration changes the circulation of the molten aluminium in the cell into small circulation flows around the protrusions. This produces a reduced slow rate of the circulated molten aluminium and stabilises the molten aluminium surface above the protruding part.”
103.I also note that the evidence suggests this particular problem of wave motion forms part of the common general knowledge in the art. In this regard the opponent’s evidence at [6] of Zhang #1 discusses with reference to the pooled configuration that:
“[A] depth of molten aluminium was part of the common general knowledge in the industry of aluminium smelting prior to 2007. In this regard it should be appreciated that the surface of the molten aluminium is not flat. It undulates (has waves) which results from movement of the aluminium. It has a heave profile as a result of magnetohydro dynamic forces. The fluctuation in the surface of the molten aluminium contributes to a loss of efficiency. Accordingly it is desirable to inhibit wave motion and other disturbances in respect of the surface of the molten aluminium…”
104.Thus in determining whether claim 1 involves an inventive step the relevant problem is the reduction of waves/fluctuations in the surface level of the molten aluminium in an electrolytic cell in pooled configuration. Further, knowledge of this problem can be attributed to the hypothetical person skilled in the art.
The hypothetical person skilled in the art
105.Neither party made submissions as to the hypothetical person skilled in the art. I am satisfied that I may consider the hypothetical person skilled in the art to be a team of people including a chemical engineer, metallurgist and industrial process technician with experience in aluminium electrolysis. In this regard, the expert declarants of both the opponent and applicant may be considered persons skilled in the art.
The common general knowledge in the art
106.The applicant summarised the common general knowledge in the art in its submissions, reflecting that identified by the opponent in their evidence (Zhang #1 at [6]). I accept that the applicant fairly summarises the relevant common general knowledge in Australia before the priority date as follows:
· Smelters included a steel shell and insulating material lining the steel shell
· Above the insulating material was a layer of refractory bricks that also aid in insulating
· The walls of the casing also had insulating layers
· Supported on the refractory bricks were cathode carbon blocks. Carbon paste was compacted between the carbon blocks, with a steel conductor bar extending longitudinally through each carbon block
· Located above was a carbon anode
· The carbon paste between the carbon blocks had a thickness of about 30 to 50 mm
· During the operation of each of these prior art aluminium smelters in Australia, a layer of molten aluminium was in contact with and covered the carbon blocks. Above the molten aluminium there was a molten electrolyte layer. The depth of the molten aluminium above the carbon blocks ranged from between 0 and 400 mm and typically the depth was between 100 and 250 mm
· The surface of the molten aluminium is not flat
The prior art base (ascertain, understand and regard as relevant)
107.The opponent relies on both documents D1 and D2 to establish obviousness. According to subsection 7(3), documentary information relevant the assessment of inventive step must be information that the person skilled in the art, before the priority date of the claims, could be reasonably expected to have ascertained, understood and regarded as relevant.
108.In relation to ascertaining the documents, relevant evidence suggesting that they would have been ascertained is the following statement by the opponent’s expert in Zhang #1 at [11]:
“Prior to 2007 I used patent searches to gather information about aluminium smelting.”
109.The applicant does not provide any contrary evidence. Thus, I am satisfied that the documents would have been ascertained. As they are both in English, I am also satisfied that they would have been understood.
110.As above, the problem to be solved by the independent claim is the reduction of waves/fluctuations in the surface level of the molten aluminium in an electrolytic cell in pooled configuration. Document D1 is directed towards an aluminium smelting cell comprising: a floor defining a cathode surface which is substantially horizontal in the longitudinal direction of an overlying anode; shaped structures projecting from the cathode surface and having exposed surfaces of aluminium wetted material; the shaped structures being positioned to cause preferential contouring of the anode, particularly at its longitudinal edges to allow for improved bubble release and to minimize cell resistivity (see abstract). In this regard, the problem solved by the invention of document D1 relates to the operation of drained mode electrolytic cells and the need for an improved cell which facilitates adequate bubble release and electrolyte flow, and low inter electrode distance operation.
111.While the document briefly discusses operation of the cell with molten aluminium levels above the shaped structures, the problem solved by document D1 relates only to drained configurations. There is no mention in document D1 of the problem of wave motion in pooled molten aluminium. Thus I do not consider that the person skilled in the art would have regarded document D1 as relevant to the problem addressed by independent claim 1. Consequently, document D1 does not form part of the prior art base for consideration of inventive step.
112.Document D2 is directed towards an aluminium electrolytic cell having a cathode cell bottom made of a series of cathode carbon blocks each having a top, side and bottom surface, the blocks being connected side-by-side transverse to the cell (abstract). The background of the invention suggests that a major drawback of prior cells is that irregular electromagnetic forces create waves in the aluminium pool and thus adversely affect the inter electrode distance (page 2 lines 25-32). In this regard document D2 seeks to provide an improved means to restrain movement of the aluminium pool on the cell bottom (page 5 lines 13-25). This corresponds to the problem solved by independent claim 1. As such I am satisfied that the person skilled in the art would regard D2 as relevant, and thus D2 forms part of the prior art base for consideration of inventive step.
Was the invention obvious?
113.The opponent relies on documents D1 and D2 in asserting that the claimed invention lacks an inventive step submitting that:
“In the alternative, if not disclosed in HZ2 and HZ3, then the electrolytic cell defined by claim 1 and 2 lacks an inventive step in view of Exhibit HZ2 and HZ3, when viewed in the light of common general knowledge that existed prior to 2007 in Australia, as established by Mr Hao Zhang.
If we take the starting position as explained by Professor Feng Naixiang, (see his paragraph 18) that the invention resides in the cathode carbon blocks having between 2 and 8 protruding parts arranged in the longitudinal direction of the carbon blocks, then again there is no invention as such an arrangement is clearly described in Exhibit HZ2 and HZ3.”
114.The opponent also added that if a specific depth of molten aluminium was not disclosed in the documents, then the evidence suggests that it is common general knowledge to operate an aluminium electrolytic cell in the range of heights defined in claim 1. In this regard the opponent suggests that there no inventive step in merely adding what both declarants agreed was a common height range of molten aluminium.
115.I note that I have already found that a person skilled in the art would not have regarded document D1 as relevant to the problem to be solved. Consequently, in considering inventive step I need only decide whether the claimed invention is obvious in view of document D2 when read in light of the common general knowledge in the art.
116.As discussed under novelty, I have found that document D2 fails to disclose both: a height of molten aluminium from the upper surface of protruding portions being about 30-200mm after the aluminium is generated; and, an electrolytic cell in pooled mode which also comprises cathode carbon blocks which have 2-8 protruding portions arranged at predetermined intervals.
117.As discussed earlier at [87], document D2 teaches the use of plural protruding portions in a drained mode electrolytic cell (figure 6 and page 20 lines 14-18). In this embodiment, the purpose of the cross-bevels/channels which relate to the protruding portions (as discussed at page 20 lines 9-14 of D2) is for draining off aluminium from the top surface of the carbon blocks to maintain aluminium in the parallel grooves at a constant level.
118.The problem to be solved by the claimed invention is the reduction of waves/fluctuations in the surface level of the molten aluminium in an electrolytic cell in pooled configuration. Importantly, there is no evidence from the opponent to explain steps that a skilled addressee in the art may have taken to arrive at the claimed invention in light of the prior art document D2 and common general knowledge. More specifically, there is no evidence of any steps a person skilled in the art may have taken to combine the teachings of figures 3 and 6 to arrive at the combination of pooled mode operation (as depicted in the embodiment of figure 3) and a plurality of protrusions in each carbon block (as depicted in the embodiment of figure 6). Instead the opponent appears to essentially rely on a disclosure of the claimed features to render claim 1 not inventive.
119.Notwithstanding the absence of any relevant evidence, I am satisfied that document D2 teaches away from the claimed solution in the sense that the feature of a plurality of protrusions is only disclosed in the context of a drained cell configuration. There is no suggestion in the document to operate the embodiment of figure 6 in a pooled mode.
120.Thus, with the identified problem as the starting point, I cannot consider that a person skilled in the art would be directly led to the invention of claim 1 whereby an electrolytic cell in pooled mode also comprises cathode carbon blocks which have 2-8 protruding portions arranged at predetermined intervals. Therefore I find independent claim 1 inventive. Claims 2-6 add further features to those defined in claim 1 and are thus also considered inventive.
Conclusion
121.The opposition is unsuccessful on all grounds. Subject to an appeal against this decision the application is to proceed to grant.
Costs
122.It is normal for costs to follow the event. In this case, Rio Tinto Alcan International Limited has been unsuccessful and I can see no reason depart from the norm. I will award costs against Rio Tinto Alcan International Limited.
Dr N.R. Madsen
Delegate of the Commissioner of Patents
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