Memcor Australia Pty Ltd v Zenon Technology Partnership
[2008] APO 8
•5 March 2008
ABSTRACTS OF DECISIONS
DECISION OF A DELEGATE OF THE COMMISSIONER OF PATENTS
Application : No. 2003271311 in the name of Zenon Technology Partnership
Title: Cyclic Aeration System for Submerged Membrane Modules
Action: Opposition under Section 59 of the Patents Act by Memcor Australia Pty Ltd
Decision: Issued 05 March 2008.
Abstract
The invention relates to a submerged membrane filtration system and particularly to using scouring air bubbles produced by an aeration system to clean or inhibit the fouling of membrane modules immersed in a tank of water containing solids.
The application was opposed on the grounds of novelty, inventive step, clarity and manner or manufacture.
The opposition was found to unsuccessful on all grounds and costs were awarded against the opponent.
PATENTS ACT 1990
DECISION OF A DELEGATE OF THE COMMISSIONER OF PATENTS
Re:Patent Application No. 2003271311 by Zenon Technology Partnership and an opposition under section 59 of the Patents Act 1990 by Memcor Australia Pty Ltd.
BACKGROUND
Patent application 2003271311 was filed on 19 December 2003 by Zenon Technology Partnership (Zenon), and is a divisional of Patent application 765966 (60738/99) filed on 7 October 1999, which claims an earliest priority date of 9 October 1998. The application was examined and advertised as accepted on 19 April 2005.
Memcor Australia Pty Ltd (Memcor) filed a Notice of Opposition on 20 July 2005. A Statement of Grounds and Particulars was filed on 21 October 2005. The filing of evidence in support, evidence in answer and evidence in reply was completed on 2 July 2007.
A hearing to deal with the substantive opposition was held in Canberra on 6 December 2007. Graeme Clark, Senior counsel instructed by Mathew Swinn, patent lawyer of Corrs Chambers Westgarth, Melbourne, represented the applicant. David Yates, Senior counsel, instructed by Peter Heathcote, patent attorney of Shelston IP, Sydney, represented the opponent. Mr Scott Pundsack also appeared over phone as an observer for the applicant.
EVIDENCE
Evidence in support consists of declarations made by:
Gregory Lawrence Leslie, dated 29 September 2006 with exhibits GLL-1 to GLL-6. He states that he is an Associate Professor of the School of Chemical Sciences and Engineering, University of New South Wales. He has had extensive experience as a researcher, consultant, adviser, teacher and project manager in the fields of micro-filtration, ultrafiltration and reverse osmosis filtration systems using membrane technology.
Peter Heathcote, patent attorney with exhibits PRH-1 to PRH-38.
Evidence in answer consists of declarations made by:
Sheng Chang, dated 6 December 2006 with exhibits SC-1 to SC-4. He states that he has been a chemical engineer since 1983 and has worked as a Research Associate, an APD Fellow and as a Research Engineer in the fields of membrane filtration and water treatment using membranes. He currently works as a Research Engineer with the applicant Zenon.
Meredith Brill, dated 6 December 2006 with exhibits MBB-1 to MBB-7.
Richard W Baker, dated 13 December 2006 with exhibits RWB-1 to RWB-9. He states that he has experience in the field of filtration technology since 1966 and is currently President of Membrane Technology and Research, Inc. which he founded in 1982 as a research and development company specialising in membrane separation technology. Although he has not worked in Australia he states that he considers that the common general knowledge in Australia in membrane technology in 1999 was on the same level as the USA.
Evidence in reply consists of declarations made by:
Gregory Lawrence Leslie, dated 29 June 2007 with exhibits GLL-7 to GLL-17.
Bruce Gregory Biltoft, dated 26 June 2007 with exhibit BGB-1. In this declaration he summarises the development of Memcor from its inception in 1981 through to the present day.
SPECIFICATION
The invention relates to a submerged membrane filtration system and particularly to using scouring air bubbles produced by an aeration system to clean or inhibit the fouling of membrane modules immersed in a tank of water containing solids. Aerators mounted below the membrane modules introduce to the tank air bubbles which rise to the surface of the tank and create an air lift which recirculates tank water around the membrane modules. When the rate of air flow is within an effective range, the rising bubbles and tank water scour and agitate the membranes to inhibit solids in the tank water from fouling the pores of the membranes.
The specification states that with typical aeration systems, an operator increases the rate of air flow to the aerators if more cleaning is required. This technique, however, stresses the membranes and also increases the amount of energy and this significantly increases the operating costs of the process. Some operators reduce the average rate of air flow by operating the aerators intermittently. This method allows for an air flow in the effective range but at the expense of the air blowers which wear rapidly when turned off and on frequently.
Another concern with typical aeration systems is that the steady state recirculation pattern in the tank water includes “dead zones” where tank water is not reached by the recirculating water and bubbles. The membranes in these zones are not effectively cleaned by the bubbles and also assume a near steady state rather than allowing them to move and shake off or avoid trapping solids.
The solution proposed by the specification is to operate the modules under an aeration regime in which the flow of gas is alternated in repeated cycles of not more than 120 seconds in duration between a higher flow rate and a lower flow rate, the lower flow rate being less than one half of the higher flow rate.
The specification concludes with independent claims 1 and 12, several appended claims and omnibus claims 26-29. The independent claims and the omnibus claims read as follows:
1. A process for cleaning or inhibiting the fouling of a membrane module having one or more filtering membranes immersed in tank water in a tank, wherein the module is operated under an aeration regime in which a flow of gas produces bubbles which flow upwards past the membranes to clean or inhibit fouling of the membranes, and the flow of gas is alternated in repeated cycles of not more than 120 seconds in duration between a higher flow rate and a lower flow rate, the lower flow rate being less than one half of the higher flow rate.
12. A device to aerate tank water in a tank containing one or more immersed membrane modules having:
(a) a gas delivery network having a plurality of distinct headers;
(b) one or more aerators in fluid communication with the distinct headers of the gas distribution system and mountable below the membrane modules;
(c) a gas supply to provide a generally constant flow rate of gas flow; and
(d) one or more valves in a valve set in fluid communication with the gas supply and having distinct outlets in fluid communication with the distinct headers of the gas distribution system,
wherein one or more valves in the valve set are mechanically or electrically linked to a valve set controller which automatically operates the valves to (i) split the initial gas flow such that at least one of the distinct headers of gas distribution system receives gas at a higher flow rate and at least one other of the distinct headers of the gas distribution network receives gas at a lower flow rate, the lower flow rate being less than one half of the higher flow rate; and (ii) switch which header or headers of the gas delivery network receive gas at the higher flow rate and the lower flow rate in repeated cycles of not more than 120 seconds in duration.
26. A process for cleaning or inhibiting the fouling of a membrane module having one or more filtering membranes immersed in tank water in a tank substantially as herein described with reference to the accompanying drawings.
27. A process for cleaning or inhibiting the fouling of a membrane module having one or more filtering membranes immersed in tank water in a tank substantially as herein described with reference to the accompanying examples.
28. A device to aerate tank water in a tank containing one or more immersed membrane modules substantially as herein described with reference to the accompanying drawings.
29. A device to aerate tank water in a tank containing one or more immersed membrane modules substantially as herein described with reference to the accompanying examples.
GROUNDS OF OPPOSITION
The statement of grounds and particulars sets out the following grounds of opposition:
The invention as claimed in claims 1-29 of the application:
a) is not a manner of manufacture within the meaning of section 6 of the Statute of Monopolies;
b) is not novel when compared with the prior art base as it existed before the priority date of the claims; and
c) is disclosed or in substance disclosed when compared with the prior art base as it existed before the priority date of the claims;
The specification does not comply with subsection 40(2) or (3).
DECISION
Both parties made oral submissions at the hearing as well as filing written submissions. I shall refer to these as well as any earlier filed evidence wherever relevant in my decision.
CLARITY
Memcor submitted that the following terms in the claims are unclear.
In claim 8, the condition that “first aerators receive gas at the higher flow rate while the second aerators receive gas at the lower flow rate” is repeated.
While I agree that this feature is repeated, I am guided by the rules of construction which state that the specification must be read as a whole and that the specification must be given a purposive construction rather than a purely literal one (Décor Corp v Dart Industries 13 IPR 385 at 400). I agree with Zenon that a person skilled in the art reading the specification as a whole would understand those words to refer to alternating high/low flow rates through the first and second aerators. I therefore find that this term is clear.
In claim 11 which defines that “the flow of gas is alternated abruptly between the higher flow rate of flow and the lower flow rate of flow”, the term “abruptly between” is unclear and meaningless in scope.
I can find nothing unclear about this term. As the specification makes clear on page 11, lines 21-28, it is preferred that the valves which vary the air flow rate are operated in a manner such that the variations in the air flow during the transition between the higher and lower flow rates is provided as an abrupt variation rather than as a smooth variation. I find that this term is clear.
In claim 19, the term “rectangular numbers” is meaningless.
The description does not describe this term and therefore I was also initially confused by this term. Zenon submitted that this term has a clear meaning and refers to a mathematical term which for example includes the numbers 2, 6, 12, 30, 42 and so on. The Concise Oxford Dictionary of Mathematics defines rectangular number as “any number which can be expressed non-trivially as a rectangular array of dots, i.e. excluding the trivial case of a single row. Thus rectangular numbers are non-prime in that they can be expressed as a x b where neither a nor b is 1”.
Given this definition, a person skilled in the art would understand that this term in the claim defines that the number of fibre membranes in each of the membrane modules should be a rectangular number. This claim is therefore clear.
In light of the foregoing I find that all the claims are clear to a person skilled in the art.
NOVELTY
It is well established that “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 invention would if the patent were valid, constitute an infringement." (Meyers Taylor Pty Ltd v Viccar Industries [1977] HCA 19; (1977) 137 CLR 228).
Infringement is said to occur where "each and every one of the essential features of that claim have been taken" (Rodi and Wienenberger AG v. Henry Showell Ltd [1969] RPC 367).
More recently in Bristol-Myers Squibb Company v FH Faulding & Co Limited (2000) 97 FCR 524 the full Federal Court said:
“….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.”
Although Memcor’s evidence in support is mainly based on only three citations, namely JP 09-192688 and WO 99/29401 against claim 1 and JP 07-185271 against claim 12, their submissions at the hearing on the ground of lack of novelty relied on eleven documents which were listed in the statement of grounds and particulars. I will now consider each of these documents.
D1) JP 09-192688 (Exhibit GLL-4)
According to the English translation of this document filed as evidence in support, document D1 relates to an intermittent aeration treatment method for purifying waste water using repeated processes of aerobic decomposition during which waste water is aerated for a fixed time and anaerobic decomposition during which waste water is not aerated for a fixed time. It discloses pulse or intermittent aeration to produce the mixing of the water in the tank during the anaerobic decomposition stage as an alternative to the conventional technique of using mixing propellers and pumps.
In paragraph 14, the document teaches that aeration from the diffuser pipe, aside from the purposes of supplying oxygen and mixing the sludge liquid, also has a role of forcibly removing any solids deposited on the membrane surface of the membrane filter. In paragraph 21 it also mentions that the intermittent aeration can provide power savings.
While D1 does not explicitly teach that the lower flow rate is less than one half the higher flow rate, it clearly teaches intermittent operation with an “air off” condition, and this “air off” condition falls within the scope of this feature. Even the claimed invention clearly teaches that the lower flow rate can be an “air off” condition and therefore this feature is disclosed in D1.
D1 further teaches that during the anaerobic decomposition stage pulse aeration need only be applied to the extent that it produces a gentle rotational flow in the activated sludge liquid. This may vary according to the size of the tank, and other factors, but if the size of the tank is from 1-3 m³, the pulse aeration time is less than 2 minutes and preferably from 30-60 seconds. If the aeration time is longer than 2 minutes, the anaerobic conditions are difficult to maintain. It also states that length of time between one pulse and the next is normally from 5-20 minutes and preferably from 10-15 minutes and if the pulse aeration cycle is less than 5 minutes the anaerobic conditions are difficult to maintain. Therefore the minimum cycle time envisaged in D1 is 330 seconds (namely 5 minutes plus 30 seconds).
Whilst Memcor agreed in their submissions at the hearing that the limitations as to cycle times stipulated in the claims can be literally distinguished from the time periods specifically stated in this citation, they argued that the selection of the cycle time of 120 seconds or less was no more than an arbitrary non-inventive selection that conferred no substantive novelty over the citation.
Zenon submitted that this argument of substantial lack of novelty was flawed and I agree. To anticipate the claimed invention, the citation must disclose all the essential features of the claimed invention. If it does not, then the claimed invention is novel. Memcor did not run the argument that the feature of the cycle time being less than 120 seconds was a non-essential feature of the invention. Even if they had, I am not convinced that they would have succeeded on this point as I can find nothing in the specification to suggest that this is only a non-essential feature. The consistory statement and the preferred embodiments clearly emphasise a cycle time of 120 seconds or less.
In light of the above I find that the invention defined in claim 1 and its dependent claims is novel over D1. I will consider the argument of non-inventive arbitrary selection under obviousness later in this decision.
D2) JP 07-185271 (Exhibit GLL-6)
D2 teaches a device for cleaning the surface of the filter membranes. It shows membranes 11A and 11B in a membrane unit 11 which is immersed in a tank 10. A gas distribution system with distinct headers and aerators 15A and 15B is disclosed. A generally constant gas supply is provided by blower 16 through a fluid communication line 17 to the headers of each set of aerators 15A and 15B. A valve set 18A, 18B is controlled to alternately switch constant gas flow from blower 16 between the aerators 15A and 15B. In the working examples, it mentions that each aerator is operated for 15 minutes giving a total cycle time of 30 minutes. D2 therefore discloses all of the features of claim 12 except for the feature of the cycle time being no more than 120 seconds.
Again Memcor argued that the selection of the cycle time of 120 seconds or less was no more than an arbitrary non-inventive selection that conferred no substantive novelty over D2. For reasons already discussed against D1, I find this argument fails. Claim 12 is therefore not anticipated by D2.
D3) WO 99/29401 (Exhibit GLL-5)
D3 relates to the scrubbing of a membrane with a continuous stream of relatively fast moving coarse bubbles. The aerator which produces the bubbles is itself quickly fouled by deposits which build up on the inner surfaces of the walls of the aerator, plugging orifices in those walls. D3 is primarily concerned with overcoming this problem. This is done by periodically flowing through a fouled aerator a two-phase mixture of flushing gas and permeate so as to produce discrete dispersed masses of permeate moving at high velocity with trapped air between the masses. The short time during which air is impeded in its escape provides unexpectedly effective removal of fouling solids in the aerator. To initiate a flushing cycle, scrubbing air is first cut off and permeate is introduced into the line and a controlled amount of flushing air is injected into the permeate line in short cycles of 1-20 seconds. Alternatively permeate and air may be introduced separately, each for a short period. A typical flushing cycle lasts from 1-5 minutes and is carried out at a frequency of 4-72 hours.
Memcor submitted that the citation therefore clearly teaches cyclical aeration for periods of 60 seconds or less which takes place within a process for cleaning or inhibiting the fouling of membranes using streams of relatively fast moving coarse bubbles flowing upwards past the membranes. They argued that it does not matter that the motivation for the cyclical aeration is the cleaning of the aerators themselves.
Zenon on the other hand argued that D3 is directed to a process for cleaning the aerator and therefore does not teach the cyclical aeration as a method for preventing the fouling of the membrane module.
I am inclined to agree with Zenon. The level of disclosure must be such that the prior art document must provide “clear and unmistakable directions” to do what is claimed, see General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd, [1972] RPC 457 at pages 485, 486:
"To anticipate the patentees 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."
Claim 1 of the opposed application is directed to a process for cleaning a membrane module and not to a process for cleaning the aerator. While the citation may teach injecting air into the permeate in short cycles of 1-20 seconds for the purpose of cleaning the aerators, there is no suggestion or indication in the document that such cyclical aeration provides improved cleaning of the membrane surfaces. In fact the document discloses that to prevent fouling, the membrane surfaces need to be scrubbed with a continuous uniform stream of air bubbles and therefore teaches away from the invention. I am unable to find in D2 clear and unmistakeable directions to do what is defined in claim 1. I therefore find that D3 does not anticipate the claimed invention.
I also note that D3 was published on 17 June 1999 whereas the opposed application claims an earliest priority date of 9 October 1998. Memcor did not provide any evidence to establish that the application is not entitled to this priority date.
D4) US 5248424 (Exhibit PRH-5)
D4 discloses a process for cleaning the surface of a membrane module having one or more membranes 42 immersed in a substrate with an aerator 50 for providing an aeration regime in which a flow of gas produces bubbles which flow upwards past the membranes to clean or inhibit fouling of the membranes. It also discloses that the flow of gas through the aerator can be continuous or intermittent, better results generally being obtained with continuous air flow. It does not disclose any further information about the cycle times for intermittent operation. D4 does not therefore anticipate the claimed invention.
D5) US 5480553 (Exhibit PRH-6)
Similar to D4 this discloses that the cleaning can be done either continuously or intermittently, but no information about the cycle times for intermittent operation is given. D5 does not therefore anticipate the claimed invention.
D6) US 5639373 (Exhibit PRH-8)
The disclosure of this document is almost identical to that of D4 and hence does not anticipate the claimed invention.
D7) US 5643455 (Exhibit PRH-9)
In D7, rather than scrubbing the membrane fibres with a rising stream of air bubbles, the fibre lumens are cleaned by backwashing with pressurised air introduced into the lumens intermittently. Although the opponent argued that D7 discloses cycle times which fall within the cycle times of the claimed invention, the fact that it does not disclose the method of scrubbing by the use of air bubbles flowing upwards past the membranes is enough to decide that this document does not anticipated the claimed invention.
D8) US 5783083 (exhibit PRH-10)
D8 discloses that the cleaning can be done either continuously or intermittently, but no information about the cycle times for intermittent operation is given. D8 does not therefore anticipate the claimed invention.
D9) JP 2946072 (Exhibit PRH-20)
D9 discloses that the cleaning can be done either continuously or intermittently, but no information about the cycle times for intermittent operation is given. D9 does not therefore anticipate the claimed invention.
D10) JP 04265128 (exhibit PRH-26)
D10 teaches a process for cleaning the surface of a membrane module 3 having one or more membranes immersed in a substrate with an aerator 9 for providing an aeration regime in which a flow of gas produces bubbles which flow upwards past the membranes to clean or inhibit fouling of the membranes. It also clearly teaches that the membrane surface can be maintained at a greater level of cleanliness by intermittently establishing a high flow rate of diffused gas per unit of time. It also discloses that the flow can be stopped during the periods of high and low flow rates. In relation to cycle times and flow rates, the examples disclose a low flow rate of 100 litres/minute for a period of 30 minutes and a high flow rate of 300 litres/minute for a period of 3 minutes giving a cycle time of 33 minutes. As the cycle time is not 120 seconds or less D10 does not anticipate the claimed invention.
D11) WO 98/28066 (exhibit GLL-14)
D11 discloses that the cleaning can be done either continuously or intermittently, but no information about the cycle times for intermittent operation is given. D11 does not therefore anticipate the claimed invention.
I therefore conclude that the claimed invention is novel over the prior art filed in evidence.
INVENTIVE STEP
To establish lack of inventive step, the common general knowledge in the art of the invention must be established and it must be shown that the claimed invention was obvious to the skilled person at the priority date, in light of common general knowledge alone or in light of common general knowledge together with prior art information (section 7). Section 7(3) further restricts the information to that which could reasonably be expected to have been ascertained, understood and regarded as relevant by the skilled person in the relevant art in Australia.
The normal approach to obviousness is the problem-solution approach. Once the problem has been formulated, and the common general knowledge and the prior art base have been determined, the question of whether the claimed solution is obvious must be addressed. The test for obviousness is whether it would have been a matter of routine to proceed to the claimed invention:
“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.”
[Wellcome Foundation Ltd v. V.R. Laboratories (Aust.) Pty Ltd (1981) 148 CLR 262]
Problem
The problem to be solved is to provide an aeration regime for effective cleaning of the membrane modules using a rising stream of air bubbles that does not (a) increase the energy or power used by the blowers or (b) rapidly wear out the blowers or (c) produce a steady state recirculation pattern in the tank water.
Obvious in the light of common general knowledge
Memcor argued that the invention defined in independent claims 1 and 12 lacks an inventive step in the light of common general knowledge in the art at the alleged priority date of October 1998. They submitted that the evidence of Associate Professor Leslie clearly establishes that the following were common general knowledge in the art at the alleged priority date of October 1998:
- Submerged membranes generally arranged in modules were used to treat liquids containing solids in waste water and water treatment applications, by the application of a transmembrane pressure across the membrane walls.
- In such applications, aerators were mounted below the membranes to introduce rising air bubbles into the tank.
- The air bubbles create an air lift which recurculated tank water around the membrane modules.
- The air bubbles agitate the membranes to inhibit solids in the tank from fouling the pores of the membranes.
- The air bubbles provide oxygen for microorganism growth in waste water applications.
- In typical aerations systems air flow rate could be adjusted (increased or decreased) if more or less cleaning was desired.
- Air flow adjustment included intermittent operation, including turning air blowers “on” or “off”.
- Turning air blowers “on” or “off” frequently leads to rapid wear of the air blowers.
9. Use of a valve arrangement to divert the flow of air between adjacent membrane modules.
10. Routine optimisation of cycle times and air flow rates to suit different applications.
Although Zenon argued that intermittent operation was not common general knowledge in the art, I note that the specification clearly asserts that some operators provide air intermittently. All the eleven documents that I have discussed earlier under Novelty teach intermittent operation. I am therefore satisfied that all of the items (1) to (8) including intermittent aeration with an “air off” condition was common general knowledge in the art at the priority date of the application.
I am also satisfied that in multi-module systems an operator performing intermittent aeration would have known that it is more practical to use a valve which can divert the flow of air between adjacent membrane modules and that they would optimise the cycle times and air flow rates to suit different applications.
Memcor submitted that the invention defined in independent claims 1 and 12 differs from this common general knowledge only in the feature of the cycle time being no more than 120 seconds.
I agree. As I have noted earlier under Novelty, intermittent operation with an “air off” condition clearly falls within the scope of the feature that the lower flow rate is less than one half the higher flow rate.
According to Memcor the specification discloses no technical advance by reference to the limitations (parameters) in claims 1 and 12 regarding the repeated cycles being of not more than 120 seconds in duration or the lower flow rate being less than one half of the higher flow rate. In fact the specification makes clear that the cycle times and the differing flow rates are a matter of choice based on the system parameters. In support of this they referred me to the teachings of the specification at page 15, lines 8-15 and 31-34 and page 16, line 36 to page 17, line 14.
They also referred to the evidence of Associate Professor Leslie who has stated it was common general knowledge in the art that the amount and rate of gas flow used for cleaning or inhibiting the fouling of membranes is very much dependent on the application to which the membrane module is applied and that once a particular application is chosen, it is a matter of optimisation to select a duration and flow rate of gas suitable to the operation of that application.
Memcor submitted that the arbitrary selection of the cycle period or the lower flow rate cannot provide an inventive step and in support referred me to Re Raychem Corporation’s Patents [1998] RPC 31 where Laddie J commented in relation to the practice of seeking to re-patent the prior art by limiting claims by reference to a series of parameters which are not mentioned in the prior art:
“What has to be determined is what technical contribution to the art has been made by the patentee. If that contribution is obvious then it is not protectable under patent law. If the patent claim consists of no more than a product or process selected by reference to a set of obviously desirable parameters, then the technical contribution is the selection of those parameters. Since the selection is obvious, so is the claim. It is permissible to look at the teaching in the specification to see what the patentee has put forward as his technical contribution. Where ….the teaching indicates that nothing novel by way of materials or processing has been used, it reinforces the conclusion that the patentee has done no more than select the obviously useful products out of the range of those which can be made with existing technology. In such a case, the patent is just for any good product”.
Zenon on the other hand argued that the features of the repeated cycles being of not more than 120 seconds in duration or the lower flow rate being less than one half of the higher flow rate are not arbitrary selections and that there is clear teaching in the specification that these features are essential to the invention and provides a solution to the problems of the prior art.
While the preferred embodiments in the specification teach that there could be variation in the cycle times depending on the application and other factors such as tank depth, design of the membrane modules, process parameters and conditions of the feed water, such variations would appear to be within the 120 seconds cycle time. For example I note that on page 15, line 13-15 it teaches that the cycle time preferably does not exceed 60 seconds where the filtration vessel is a typical municipal tank. Similarly all of the six examples described have a cycle time of less than 120 seconds. Whilst none of the examples show that the invention would not work properly or the same results achieved if the cycle time was above 120 seconds I note that on page 17, lines 9-11 the specification clearly states that “long cycles of 120 seconds or more may result in parts of a membrane module 20 not receiving bubbles 36 for extended periods which can result in rapid fouling.”. I consider that this is a again a clear indication that the feature of the cycle time being less than 120 seconds is an essential feature of the invention and not an arbitrary selection.
Similarly I note that in all six examples the lower flow rate is either zero (air off condition) or less than one half the higher flow rate when it is not in an air off condition. Again I am satisfied that this feature is an essential feature and not an arbitrary selection.
As I have noted earlier the claimed invention differs from the common general knowledge only in the cycle time for intermittent operation being 120 seconds or less. Nothing in Memcor’s evidence or submissions support the argument that the selection of a cycle time of 120 seconds or less would have been obvious to a person skilled in the art. While operators would routinely optimise cycle times and air flow rates to suit different applications there is nothing to suggest that operators were aware of the benefits of a short cycle time of 120 seconds or less.
I therefore find that there is nothing obvious in the selection of the parameter of the cycle time being 120 seconds or less. The claimed invention is therefore inventive when compared to the common general knowledge in the art at the priority date of the application.
Obvious in light of the prior art
Whilst Memcor did not specifically argue that the claimed invention is not inventive over the prior art they relied on under the ground of lack of novelty, I will briefly consider these prior art documents for lack of inventive step.
All of the documents D1-D11 except D3 and D7 teach a method for cleaning the membrane surfaces using a stream of rising air bubbles.
Zenon submitted that D1, D2, D9 and D10 are Japanese documents and there is no evidence to suggest that any English translation would have been available before the priority date hence enabling them to be understood by the skilled person in Australia.
I am not convinced by Zenon’s argument. Even their expert Dr Baker recognises that Japan was a country with a known interest in the employment of membrane technology. English abstracts of Japanese patent documents have been available well before the priority date. Whilst D1 is primarily directed to providing power savings by the use of intermittent aeration, it also clearly teaches that the aeration has a role in forcibly removing any solids deposited on the filter membrane surface (paragraphs 12 and 14). Similarly D2, D9 and D10 are all clearly directed to cleaning the membrane surface.
In relation to document D3 whilst the citation may teach injection of air in repeated cycles of 120 seconds or less in the context of cleaning the aerators with a two-phase mixture of flushing gas and permeate, I note that there is no suggestion or indication in the document that such cyclical aeration provides improved cleaning of the membrane surfaces as well. A person skilled in the art would not have considered this document relevant to solving the stated problem.
While document D7 relates to a method of cleaning the membrane surfaces it achieves this by backwashing with pressurised air introduced into the lumens intermittently. Although the pressurised air bursts out as bubbles on the external surface of the lumens this system works differently to the method of cleaning using a rising stream of air bubbles external to the lumens as in the claimed invention. It is therefore my view that a person skilled in the art would not consider this document relevant to solving the stated problem.
I am therefore satisfied that all of the documents that I considered under Novelty except D3 and D7 are documents that would have been ascertained, understood and regarded as relevant by a person skilled in the art.
As I have discussed under Novelty, none of the documents D1-D11 teach a cycle time of 120 seconds or less. In relation to the feature of the lower flow rate being less than one half the higher flow rate, I note that while most of these documents do not explicitly teach this feature, they all teach intermittent operation with an “air off” condition, and this “air off” condition falls within the scope of this feature.
The question that I therefore need to answer is whether a person skilled in the art faced with the problem stated earlier would have as a matter of routine arrived at the solution that the cycle time should be no more than 120 seconds.
Associate Professor Leslie states that it was common general knowledge in the art that the amount and rate of gas flow used for cleaning or inhibiting the fouling of membranes is very much dependent on the application to which the membrane module is applied and that once a particular application is chosen, it is a matter of optimisation to select a duration and flow rate of gas suitable to the operation of that application. He has further stated that such optimisation is and was before the priority date of October 1998 routinely carried out in the field during the commissioning and testing of specific membrane filtration systems.
While I agree with Associate Professor Leslie that a person skilled in the art would routinely optimise to suit the application, I am unable to see any teaching in these citations or in the common general knowledge in the art which would motivate the skilled person to try short cycle times of 120 seconds as part of their optimisation.
Documents D2 and D10 teach a cycle time of 30 minutes. Although D4, D5, D6, D8, D9 and D11 do not disclose any cycle times it does not necessarily follow that they teach any and all cycle times. A skilled person following the teachings of these documents would employ cycle times that would be considered normal for that application. Memcor has not provided any evidence to indicate that such normal cycle times would be 120 seconds or less. The teachings of D2 and D10 would appear to suggest that the normal cycle times were considerably higher than 120 seconds. I am therefore not convinced that a skilled person would as a matter of routine arrive at a cycle time of 120 seconds or less based on the teachings of these documents.
While D1 teaches intermittent aeration with a cycle time of 330 seconds, this intermittent aeration is provided in the anaerobic stage for the purpose of providing a gentle rotational flow in the activated sludge liquid. The cycle time is chosen so that the sludge is sufficiently mixed and at the same time the anaerobic conditions can be maintained. It clearly discloses that if the cycle time is less than 5 minutes, then anaerobic conditions are difficult to maintain. While the specification does teach that the aeration also has a role of forcibly removing any solids deposited on the membrane surface, this does not appear to be restricted only to the intermittent aeration in the anaerobic stage. I note that during the aerobic stage the aeration appears to be continuous and there is no suggestion that the intermittent aeration during the anaerobic stage provides any better cleaning of the membrane surfaces than the continuous aeration in the aerobic stage. Again I am not convinced that a person skilled in the art would be motivated by the teachings of this document to try a cycle time of 120 seconds or less as part of routine optimisation in the hope that this will provide improved cleaning of the membranes.
In light of the foregoing I find that the invention defined in the claims is inventive compared to the prior art documents.
MANNER OF MANUFACTURE
In relation to this ground of opposition, Memcor did not serve any evidence in support nor did they make any submissions at the hearing. It appears from the statement of grounds and particulars that this ground is solely based upon the grounds that the claimed invention is not novel or inventive. As I have found that the claimed invention to be both novel and inventive, it follows that the claimed invention is a manner of manufacture.
CONCLUSION
The opposition fails on all the grounds which were relied on.
Unless the Commissioner is served with a notice of appeal within 28 days of the date of this decision, I direct that the application proceed to sealing.
COSTS
In proceedings such as these it is usually the case that costs follow the event. I see no reason to vary that approach on this occasion. I therefore award costs against the opponent Memcor Australia Pty Ltd.
R Subbarayan
Delegate of the Commissioner of Patents05 March 2008
Patent attorneys for the applicant: Corrs Chambers Westgarth, Melbourne
Patent attorneys for the opponent: Shelston IP, Sydney
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