WorleyParsons Services Pty Limited v Hatch Pty Ltd

[2014] APO 72

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

WorleyParsons Services Pty Limited v Hatch Pty Ltd [2014] APO 72

Patent Application:                2005250509

Title:Thick Slurry Heating System

Patent Applicant:                   Hatch Pty Ltd

Opponent:  WorleyParsons Services Pty Limited

Delegate:  Rhys Munzel

Decision Date:  4 November 2014

Hearing Date:  13 August 2014, in Canberra

Catchwords:  PATENTS – s59 – opposition to grant of a patent – heat exchange systems for heating slurries – inventive step – manner of manufacture – clarity and/or succinctness – full description – fair basis – utility – opposition unsuccessful.

Representation:  Patent applicant:  Mr Ben Fitzpatrick of council, instructed by Mr Peter Caporn of Wrays

Opponent:Freehills Patent Attorneys

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

Patent Application:                2005250509

Title:Thick Slurry Heating System

Patent Applicant:                   Hatch Pty Ltd

Date of Decision:                   4 November 2014

DECISION

The opposition fails on all grounds. Subject to an appeal against this decision the application is to proceed to grant. No award of costs is made.

REASONS FOR DECISION

1.   Patent application 2005250509 (“the application”) currently in the name of Hatch Pty Ltd (“Hatch”) was examined and accepted by the Commissioner, and subsequently opposed by WorleyParsons Services Pty Limited (“Worley Parsons”). As examination was requested before 15 April 2013 substantive amendments of the Patents Act 1990 (Cth) (“the Act”) brought about by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (Cth) (“the Raising the Bar Act”) do not apply to this opposition.

2.   Hatch and WorleyParsons each rely on expert evidence in the form of declarations.  WorleyParsons’ evidence in support was provided by Gerald Roach, Daniel Thomas and Roger Henning.  Hatch’s evidence in answer was provided by David Boger and Mark Edwards. WorleyParsons’ evidence in reply was provided by Daniel Thomas. David Boger provided further evidence on behalf of Hatch. Each declaration included annexed exhibits.  I will refer to the evidence where appropriate. When referring to a specific declaration, I will identify this by using the declarant’s surname and declaration number. For example, I would identify Daniel Thomas’ second declaration as “Thomas 2”. Furthermore, I would identify Thomas’ first annexed exhibit as “DT-1”.

3.   The hearing occurred on 13 August 2014.  Ben Fitzpatrick and Peter Caporn attended on behalf of Hatch while WorleyParsons relied on its written submissions. Cherie van Wensveen, a representative of Hatch, also attended the hearing.

Onus

4.   As I noted above substantive amendments brought about by the Raising the Bar Act do not apply to this opposition. The onus therefore rests with WorleyParsons to clearly establish its case. In establishing that any ground of opposition succeeds, the Commissioner should be “clearly satisfied that the patent, if granted, would not be valid” (F. Hoffman-La Roche AG v New England Biolabs Inc [2000] FCA 283 at [67]).

Grounds of Opposition

5.   WorleyParsons relied on the following grounds of opposition:

• Lack of inventive step;
• Lack of a manner of manufacture;
• Lack of clarity and/or succinctness;
• Lack of full description;
• Lack of fair basis; and
• Lack of utility.

The nature of the disclosed invention

6.     Before construing the specification, I note what Middleton J said 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.”

7.   The specification is entitled “Thick Slurry Heating System” and describes the invention as relating to a heating system used in processing dense slurries and similar types of viscous fluids, in particular dense slurries handled in the Bayer digestion process (at page 1 lines 3-6).

Background to the invention

8.   The specification firstly describes the Bayer process wherein bauxite (an ore from which aluminium is obtained) is usually wet milled with a caustic soda solution and the resulting bauxite slurry (referred to as “thick bauxite slurry”) must be heated before further dilution with hot caustic soda, after which it is conveyed to digestion plants to extract aluminium hydroxide (at page 1 lines 3-10).

In the past two methods of heating thick bauxite slurry were utilised – direct and indirect heating (at page 1 lines 14 and 15). In direct heating steam or vapour is injected into the slurry. This method is often employed because the equipment used is simple and reliable; however it dilutes the process liquor stream with condensate (at page 1 lines 17-23). In indirect heating heat exchangers or the like provide the heat (at page 1 lines 15 and 16). However properties of the slurry create several problems (at page 2 lines 1 and 2):

• it is essentially viscous. It has a shear stress at zero flow and exhibits marked non-Newtonian behaviour (at page 2 lines 2 and 3). Its viscosity causes flow to be near laminar at the velocities employed in conventional heat transfer equipment, which in turn causes moderate heat transfer coefficients (compared with turbulent flow – at page 2 lines 4-7); 
• its solids content has a tendency to settle and the potential to obstruct flow (at page 2 lines 3 and 4). This renders the use of traditional heat transfer equipment unreliable, involving frequent cleaning (at page 2 lines 9-12).

9.   The specification notes that several types of heat exchangers have been employed to heat thick bauxite slurry, including spiral heat exchangers and shell and tube heat exchangers (at page 2 lines 13-17 and 26).

10.  Spiral heat exchangers have relatively small heat transfer areas with high capital and maintenance costs (at page 2 lines 16 and 17). Their small heating area requires a number of heaters to be assembled together to make up a suitable process unit (at page 2 lines 17 and 18). These assemblies require appropriate distribution manifolds at both the inlet and outlet of each heater, which are complex and expensive. Spiral heaters are bulky pieces of equipment and require considerable space for maintenance access (at page 2 lines 19-23).

11.  Shell and tube heat exchangers have been tried in undiluted slurry heating however they experience significant problems (at page 2 lines 26 and 27). The flow path offered by conventional 25 or 38 mm diameter tubes is insufficient to prevent blockages (at page 2 lines 27-30). The viscosity and non-Newtonian behaviour of the slurry results in poor mixing between of the slurry moving through the tube, which in turn leads to reduced heat transfer (at page 3 lines 1-11). As the bauxite slurry is a “shear thinning fluid” plug flow through the tube may occur which effectively involves no mixing and renders indirect slurry heating practically impossible (at page 3 lines 23-31).

12.  The specification notes that conventional shell and tube heat exchangers have a large number of small tubes, with multiple passes within a single large shell. These tubes are connected by large channel sections (at page 4 lines 11-14). Large channel sections have a tendency for solids to settle-out and collect at the bottom, leading to an increased likelihood of blockages in tubes from the bottom of these channels (at page 4 lines 14-16). While all indirect heating equipment in thick slurry service require frequent cleaning and descaling, cleaning of conventional shell and tube heat exchangers require the removal of large channel sections and the possible replacement of tubes which is labour intensive (at page 4 lines 16-20).

13.  For slurries the lower flow velocity limit though the tubes is determined by preventing laminar flow (at page 4 lines 21-24). Velocities of about 2 m/s are therefore preferred (at page 4 line 24). Given the velocity, small tubes will require a higher driving force to maintain flow. This higher pressure must be added to the back pressure maintained on the heater to prevent slurry boiling at the laminar sub-layer in the tubes (at page 4 lines 27-30).

The object of the invention

14.   The stated object of the invention is to provide an alternative heating system for indirect heating of thick slurries generally (at page 5 lines 11 and 12). 

The nature of the invention described

15.  The broadest form of the disclosed invention involves a slurry heating system comprising a plurality of single pass shell and tube heat exchanger units (at page 5 lines 18-30). Each single pass heat exchanger unit comprises a plurality of inner tubes arranged spaced apart within an outer tube (i.e. shell) and an internal wall proximal to each opposed end of the inner tubes to isolate a heating volume (i.e. the shell-side) located between the internal walls from the slurry containing volume (i.e. the tube-side) located within the inner tubes and beyond either end of the inner tubes bound by the internal walls (at page 5 lines 19-26). Each exchanger unit has a removable cover at least at one end to allow physical access to open ends of the inner tubes (at page 5 lines 26-28). The exchanger units are arranged in series with adjacent units connected by an interconnecting pipe or other interconnecting system that provides some turbulence in slurry flow between adjacent units (at page 5 lines 28-30).   

16.  After the broadest form of the invention is described the specification lists a number of preferred features. Several pertinent preferred features include:

• the interconnecting pipe intersects the outer tube between one of the internal walls and adjacent the removable cover (at page 6 lines 5 and 6);
• the cross-sectional area of the interconnecting pipe is less than the combined cross sectional area of the inner tubes of each exchanger unit (at page 6 lines 14-19);
• each exchanger unit comprises 10-60, preferably 30-60 inner tubes (at page 6 lines 24-27);
• the slurry heating system comprises 3 to 12 exchanger units, more preferably 3-10, 3-7, 4-6, or 5 exchanger units in series (at page 6 lines 4-12).

·the slurry heating system has a restrictor or pressure controller to maintain a higher pressure of the slurry with the slurry heating system (at page 7 lines 16-19).

17.  To illustrate the preferred embodiment of the invention I reproduce Figs. 1-4 of the specification below:

18.  Figs. 1-4 provide different views of a slurry heating system comprising five single pass heat exchangers 11, 12, 13, 14 and 15 connected by pipe connections 21, 22, 23, 24 (at page 9 lines 1-5). Each heat exchanger unit comprises 34 inner tubes 30 enclosed in an outer tube (i.e. shell) 32 (at page 9 lines 7-9). The inner tubes are sealed into an internal wall 35 (at page 9 lines 9-11). The internal walls create slurry chambers 41-50 that distribute the slurry into and receive slurry from the inner tubes (at page 9 lines 13-15). Slurry enters slurry chamber 41 of the first heat exchanger unit 11 via inlet 70 and heated slurry exits the last heat exchanger unit 15 via slurry outlet 80 (at page 10 lines 7 and 8). Each outer tube 32 is furnished with a quick opening blind 60 at each end providing access to the slurry chambers (at page 9 lines 28-30). Steam is provided to the shell side of heat exchangers via a heating fluid header 100 and heating fluid injection inlets 92. Steam cools as it heats the slurry inside and condensate from the shell side is collected into drains 110 via condensate outlets 94 (at page 11 lines 1-9). 

19.  The cross sectional area of the flanged pipe connections is preferably about 0.75 times the sum of the area of the inner tubes (at page 9 lines 19-27). This change in area provides a relative velocity difference in the pipe connections compared with the inner tubes. This assists in creating turbulent flow, and significantly increases heat transfer efficiency in the next pass at page 11 lines 23-27).

20.  Perceived advantages of the disclosed invention are further discussed at page 13 lines 16-26:

“The invention has a number of advantages over hitherto known methods for heating bauxite slurry. The invention achieves process benefits of indirect heating, avoiding unwanted dilution that causes lower caustic concentrations in slurry leaving digestion and hence consequent constraints on digester productivity. The introduction of turbulent zones avoids need for large heat exchange areas, usually resulting from inherently low slurry film heat transfer coefficients in high bauxite slurry viscosities with inherent low Reynolds numbers. Thus a benefit of smaller heat transfer apparatus is reduced capital cost and in addition, lower operating cost due to reduced de-scaling requirements. The invention achieves high heat fluxes without risk of slurry boiling in proximity to the inner tube walls (and resulting scale generation).”

Construing the claims

21.     The correct approach 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]:

"Words in a claim should be read through the eyes of the skilled addressee in the context in which they appear. Words used in a specification are to be given the meaning which the person skilled in the art would attach to them, having regard to his or her own general knowledge and to what is disclosed in the body of the specification …  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".

22.  The specification ends with 23 claims. Claims 1 is an independent claim while claims 2-22 are dependent on claim 1. Claim 23 is an omnibus claim relying on reference to the drawings. Claim 1 is reproduced below:

“A slurry heating system comprising a plurality of tube heat exchanger units, each of said units comprising a plurality of inner tubes arranged spaced apart for parallel single-pass operation, contained within an outer tube, each said unit having an internal wall located proximal to each opposed end of said inner tubes to fluidly isolate a heating volume from a slurry containing volume; said heating volume being located between said walls, said outer tube and said inner tubes, and said slurry containing volume being located within said inner tubes and beyond either end of said inner tubes bound by said walls; each said unit having a removable cover at least at one end to allow physical access to open ends of said inner tubes for cleaning purposes, said plurality of units being arranged in series with adjacent units in the series being connected by an interconnecting pipe or other interconnecting system that provides some turbulence in slurry flow between adjacent said units.”

23.  The claim defines a heating system comprising a plurality of single pass shell and tube heat exchangers. The heat exchangers are configured such that they comprise a plurality of inner tubes arranged spaced apart and in parallel within the outer shell. An internal wall is provided at each opposed end of the inner tubes to separate the shell side of the exchanger from the tube side. At least one end of each exchanger comprises a removable cover allowing access to the tube side of the exchanger for cleaning purposes. The heat exchangers are connected by means such as a pipe that will in operation induce (that is, introduce or increase) turbulence in the slurry flow between adjacently connected units (Boger 1, at paragraphs [64] and [65]; Edwards 1, at paragraph [61]).

24.  WorleyParsons noted that while the stated objective relates to thick slurries the claims define a “slurry heating system” (that is, one suitable for use with slurries generally and not exclusively thick slurries). I am not certain what structural implications the broader preamble would have on whether a heating system – otherwise having all the features of claim 1 – would fall within the scope of the claim. The specification and the evidence suggests that for thick slurries one would preferably use larger diameter tubes however one may still, perhaps not without maintenance issues, heat a thick slurry using standard diameter tubes (the specification at page 2 lines 27-30; Roach 1 at paragraphs [51]-[53]; Thomas 2 at paragraph [11]; Boger 1 at paragraph [50]). I surmise for thin slurries it is easier to induce turbulence in an interconnecting system configuration – though this is not addressed in evidence.

25.  Omnibus claim 23 defines “a heating system substantially as herein described with reference to the drawings”. As I discussed above the heating system described broadly corresponds with that defined in claim 1. I consider the scope of claim to 23 to fall within that of claim 1.

Inventive step

26. Subsection 7(2) of the Act states that an invention is taken to involve an inventive step unless it would have been obvious to a person skilled in the art in the light of the common general knowledge, considered alone or together with the prior art. A document is prior art for this purpose if "a skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood, regarded [the document] as relevant" (s 7(3)).

27.     The test for whether an invention is obvious is whether it would have been a matter of routine to proceed to the claimed invention. In Wellcome Foundation Ltd v V.R. Laboratories (Aust.) Pty Ltd [1981] HCA 12 at [45], 148 CLR 262 at 286 Aickin J stated:

"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."

28.  The High Court, in Aktiebolaget Hassle v Alphapharm Pty Ltd [2002] HCA 59; (2002) 212 CLR 411 endorsed this test (at paragraphs [50]-[52]) and recognised it as similar to the “Cripps question” (at paragraph [53]). I generalise the Cripps question as follows: would the person skilled in the art (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 solution to the problem?

The problem

29.  Hatch identified the problem to be solved as that identified in the specification. The heating of thick slurries via indirect heating caused specific issues such as:

• the viscosity of thick slurries was conducive to laminar flow in existing indirect heating systems, and laminar flow provided less effective heating due to a lack of mixing in the tubes when compared to turbulent flow (identified at page 2 lines 1-7);
• the shear-thinning behaviour of thick slurries such as thick bauxite slurries could result in plug flow, which further limited effective heat transfer to the slurry when compared to laminar flow (identified at page 3 lines 23-26);
• the reduced heat transfer caused by laminar or plug flow could cause overheating and boiling of the fluid at the tube wall. This could in turn cause tube scaling (identified at page 3 lines 10-14);
• solids in a thick slurry tended to settle out and cause blockages (identified at page 4 lines 14-17);

·the design of conventional shell and tube exchangers included large bolted channel sections at each end which required labour intensive operations to clean and descale (identified at page 4 lines 17-20).

30.  While the explicit object of the invention was to provide an alternative indirect heating system (at page 5 lines 11 and 12) I identify the implicit object as providing a useful indirect heating system in view of the above problems generally. 

31.  I note the hearing for this opposition was held on 13 August 2014. On 12 August 2014 the AstraZeneca AB v Apotex Pty Ltd [2014] FCAFC 99 judgment was handed down. In this judgment Besanko, Foster, Nicholas and Yates JJ noted (at paragraph [203]):

“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.”

32.  I am satisfied that these types of issues were recognised by the person skilled in the art (settling of solids – Roach 1, at paragraph [44]; Edwards 1, at paragraph 23: fouling – Boger 1, at paragraph 40; Edwards 1, at paragraph [38]: the avoidance of laminar flow – Boger 1, at paragraph 33: boiling the slurry – Boger 1, at paragraph [34]: labour intensive and regular cleaning and maintenance – Edwards 1 , at paragraphs [38], [46] and [47]; Boger 1, at paragraph [40]). I am satisfied this is a relevant problem to consider.

33.  Whether the preamble to claim 1 refers to slurries or thick slurries it is open to WorleyParsons to provide an alternative problem or problems which, provided they form part of the common general knowledge or s 7(3) information, I could consider in determining whether the claimed invention involves an inventive step. However WorleyParsons has not submitted an alternative problem to consider.

The person skilled in the art

34.  Hatch submitted that the person skilled in the art would be:

“a team of persons including chemical engineers, mechanical engineers, metallurgists and design engineers, who have a practical involvement in the design of heat exchangers for use in a heating system”

35.  WorleyParsons alternatively submitted that the person skilled in the art would be a chemical or mechanical engineer working in the field of thick slurries (WorleyParsons’ submissions, at paragraph [6]). Each party’s submissions are supported by evidence (for WorleyParsons – Roach 1, at paragraphs [30]-[33]; for Hatch – Thomas 1, at paragraph [10]); Boger 1, at paragraph [60]).

36.  WorleyParsons drew on Dr Roach’s statement that the design of the tubes and the required turbulence and flow rates is “the domain of the chemical engineers with whom I work” (Roach 1, at paragraph [27]). WorleyParsons resultantly submitted that evidence provided by a chemical or mechanical engineer should be preferred over Dr Roach (who is a metallurgist). Where evidence relates to advanced matters of tube design and fluid flow characterisation I accept a chemical engineer’s evidence may be preferred to that of Dr Roach. Nevertheless he demonstrates relevant experience in matters such as heat exchanger fouling (Roach 1, at paragraphs [6]-[9]) and WorleyParsons’ experts (Boger 1, at paragraph [60]; Edwards 1, at paragraph [51]) acknowledge his experience. I am also satisfied he acknowledges where he lacks expertise (see for example Roach 1, at paragraph [55]).

37.  I identify the person skilled in the art to be a team including chemical, mechanical and design engineers and potentially metallurgists having experience in the design of heat exchangers to heat slurries, in particular thick slurries.

The common general knowledge

38.  In Minnesota Mining & Manufacturing Co v Beiersdorf (Australia) Limited (1980) 144 CLR 253 292, Aickin J stated that the common general knowledge

“forms the background knowledge and experience which is available to all in the trade in considering the making of new products, or the making of improvements in old, and it must be treated as being used by an individual as a general body of knowledge”

Such knowledge is not limited to what is memorised but may include publications of technical and detailed information that the skilled worker would habitually consult (Aktiebolaget Hassle and Astra Pharmaceuticals Pty Limited v Alphapharm Pty Ltd 51 IPR 375, at paragraph [73]).

Shell and tube heat exchangers: single and multiple pass

39.  Each expert had a familiarity with shell and tube heat exchangers (Roach 1, at paragraphs [23]-[29]; Thomas 1, at paragraphs [9]-[30]; Boger 1, at paragraphs [27] and [28]; Edwards 1, at paragraph [19]). A single pass heat exchanger is known as the type where the slurry flows into an inlet head and once through a number of small parallel tubes that are heated externally by steam, before recombining in the exit head; the slurry does not change direction while traveling through the heat exchanger (Roach 1, at paragraph [24]). In a two pass heat exchanger the heads contain baffles which direct the slurry through half of the tubes in one direction and then back down the other half (Roach 1, at paragraph [25]). It is possible to have four or more passes in a heat exchanger (Roach 1, at paragraph [25]).

Series of connected heat exchangers

40.  Providing a series of connected heat exchangers is known (Roach 1, at paragraphs [61]-[65]; Edwards 1, at paragraphs [34] and [35]; Boger 2, at paragraph [11] – see also the specification at page 2 lines 16-18). Typically a series of heat exchangers would be located next to one another where interconnecting pipes join the outlets and the inlets (Roach 1, at paragraphs [61] and [62]).

The connection between adjacent heat exchangers

41.  Interconnecting pipes join adjacent heat exchangers (Roach 1, at paragraph [61]). Interconnecting pipes, like the rest of a heat exchanger, are traditionally designed to operate in the turbulent regime (Roach 1, at paragraph [77]; Thomas 1, at paragraphs [29] and [30]; Boger 1, at paragraphs [33], [45] and [64]). I note however that to my mind this is not necessarily equivalent to a configuration which “provides” turbulence.

42.  Positioning the interconnecting pipe to intersect the outer tube between each end of the head is described by Dr Roach as “what you always do” (Roach 1, at paragraph [78]). Mr Edwards disagreed and noted he is aware of a design where the interconnecting pipe comes out the end of the heat exchanger and thus does not intersect the outer tube (Edwards 1, at paragraph [42]). I infer from Mr Edwards’ evidence that, while the discussed location is not “what you always do” (as he is aware of instances where other configurations were used), it is what you usually do (see also Thomas 2, at paragraph [42] wherein Dr Thomas describes the arrangement as “simply common practise”). Providing an interconnecting pipe which intersects the outer tube would necessarily require the slurry to undergo a sharp turn when passing from the inner tubes of unit to the next (Roach 1, at paragraphs [69] and [77]; Boger 1, at paragraph [64]; Edwards 1, at paragraph [61]).

43.  The cross sectional area of an interconnecting pipe in comparison to the total cross sectional area of the inner tubes was a matter for expert discussion (Roach 1, at paragraphs [49] and [53]; Thomas 1, at paragraph [21]; Boger 1, at paragraphs [71] and [72]; Edwards 1, at paragraphs [31], [57] and [58]; Thomas 2, at paragraph [43]). There are considerations which are usually applied in determining an interconnecting pipe diameter including: pumping and piping costs and the potential for scaling, settling and erosion (Thomas 1, at paragraph 11). However standard pipe design criteria need not be followed “blindly” (Edwards 1, at paragraph [58]) and special considerations may apply to thick slurries which are non-Newtonian (Boger 1, at paragraph [72]). From this evidence I conclude that selecting an interconnecting pipe with a cross sectional area of 0.5-1.0 times that of the inner tubes would not be unusual using standard criteria and presuming certain conditions however other considerations may apply leading to selection of a different interconnecting pipe area.

Covers

44.  Covers are known to allow inspection of the tubes without disconnecting pipework or using a crane to remove the head (Roach 1, at paragraph [70]; Edwards 1, at paragraph [46]). Heads without covers are cheaper to manufacture and are therefore selected where inspection is required less often (Roach 1, at paragraph [70]). Quick opening blinds are also known and may be used with smaller heat exchangers for quick opening with a davit arm (Edwards 1, at paragraphs [46] and [47]).

Thick and dilute slurries

45.  Whether a slurry is thick or dilute will depend on: solids concentration, particle size and size distribution and surface chemistry (Boger 1, at paragraph [24]). A thick slurry has high viscosity and generally non-Newtonian behaviour while a dilute slurry has lower viscosity and generally Newtonian behaviour (Boger 1, at paragraph [25]).

Heating systems used with bauxite slurries

46.  The different stages leading to digestion involve heating bauxite slurries at different solids concentrations (Edwards 1, at paragraph [17]). During pre-desilication bauxite slurry is kept at high solids concentration as a “thick slurry” (Edwards, at paragraph [17]). After desilication the bauxite slurry is diluted forming a dilute slurry (Edwards, at paragraph [17]). This evidence is consistent with the specification which notes that thick bauxite slurry is heated prior to dilution and then conveyed to the digestion plants (at page 1 lines 8-11).

47.  Dr Roach provided the bulk of WorleyParsons’ evidence on known use of heat exchangers in the Bayer process. He states (Roach 1, at paragraph [16]):

“In some Bayer processes, slurry heat exchangers are used for heating up the slurry and caustic liquor mixture. In other Bayer processes heat exchangers heat up the liquor separately and the heated liquor is then combined with a high density slurry. I was asked to focus on slurry heat exchangers.”

In view of this statement I agree with Mr Edwards (Edwards 1, at paragraph [17]) that Dr Roach’s evidence (at least in his first declaration) is directed to heating dilute slurries (see Roach 1, at paragraphs [42], [65] and [74]-[76]).

48.  Dr Roach’s evidence distinguishes between vertical and horizontal heat exchangers and notes that multipass heat exchangers are usually vertical while single pass heat exchangers are usually horizontal (Roach 1, at paragraph [28]). Dr Roach states that he has personally only seen vertical heat exchangers (Roach 1 at paragraph [61]) and considers them better suited to heating slurries (Roach 1, at paragraph [44]). However he would expect a horizontal slurry heat exchanger to be single pass to avoid slurry settling and minimise abrasion in the head region (Roach 1, at paragraphs [44]-[46]). In discussing the connection of horizontal heat exchangers in series Dr Roach notes (Roach 1, at paragraph [62]):

“If the heat exchangers were horizontal, as I have seen in liquor heaters, they are again be [sic] placed side by side. The heat exchangers I have seen are multi-pass, so the inlets and outlets are all along one side.”

49.  I take from his evidence that Dr Roach has not personally seen heating of slurries performed by a series of single pass heat exchangers, though he considers it part of the common general knowledge. To minimise settling and abrasion in the head region he would minimise the number of passes (Roach 1, at paragraphs [44]-[46]). His reasoning on this point is unclear to me as he also explains that: (a) to avoid settling one would seek to keep the flow agitated and that multipass systems increase turbulence though each change in direction (Roach 1, at paragraphs [44] and [46]) and (b) wear on the heads is a minor issue because the tubes are thinner so wear problems tend to arise first there (i.e. before wear in the head region becomes a problem – Roach 1, at paragraph [56]).  Dr Roach does not discuss any experience he has dealing with thick slurries, though he notes that he would expect higher solids concentration to cause increased abrasion and thixotropic behaviour such that he would be further likely to select a single pass heat exchanger (Roach 1, at paragraphs [75] and [76]).

50.  Mr Edwards provided Hatch’s answer to Dr Roach on heating in the Bayer process. Firstly, he described the dilute slurry heaters he was aware of as exclusively multiple pass, though he did not extrapolate on why these were selected (Edwards 1, at paragraphs [17] and [18]). He also disagreed that the number of passes would be a relevant consideration when selecting between vertical and horizontal heat exchangers; considerations he considered relevant instead included: space limitations, maintenance access, settling in the tubes, flushing requirements and cost (Edwards 1, at paragraph [22]). On the issue of wear Mr Edwards noted that an increased number of passes would not necessarily increase wear but rather increase the number of areas subject to wear (Edwards 1, at paragraph [24]). In his view the severity of the wear is related to slurry velocity and the size of the head volume (Edwards 1, at paragraph [26]). For thick slurries he considered that wear would be a lesser consideration than the additional mixing that results from multiple passes (Edwards 1, at paragraph [24]).

51.  Dr Thomas, in reply to Mr Edwards, cited two publications he submits show a series of single pass heat exchangers used to heat bauxite slurry. They were the D2 and D3 documents which I discuss below. Whether these documents show that single pass heat exchangers had been used before I am not satisfied they clearly establish such an approach was widespread or otherwise generally well known. I will review them as potential s 7(3) prior art below.

52.  The evidence does not establish that it was a usual or known practice to heat thick slurries using a series of single pass heat exchangers. Dr Roach’s declaration relates to dilute slurries and Dr Thomas’ second declaration, to the extent that it relates to use of single pass heat exchangers, is a review of potential s 7(3) prior art rather than of the common general knowledge. In relation to dilute slurries Dr Roach expresses a preference for less passes and states that he would expect a horizontal heat exchanger to be single pass. However it seems that he has not personally seen a series of single pass heat exchangers. His reasoning for expecting use of a single pass heat exchanger is for the reasons I set out above unclear. While I do not discount his evidence on those points I am not persuaded I should discount Mr Edwards’ contradictory evidence. In response to a submission of WorleyParsons, I am further not satisfied that the disclosure of D2 (which I am not satisfied necessarily represents the common general knowledge) means I should discount Mr Edwards’ evidence. The evidence does not clearly establish that it known to use a series of single pass heat exchangers to heat thick or dilute slurries.

Applying the test for inventive step

53.  I am satisfied that single pass heat exchangers were known. I am further satisfied that each of the following were known: connection of heat exchangers in series; interconnecting pipe configurations having sharp turns that would provide some level of turbulence; and covers providing easy access to heat exchanger internals. However WorleyParsons are not required to only establish that each element of the invention was known. They must also establish that one would be directly led to try combining them, thereby arriving at the invention, in the reasonable expectation it might well solve the relevant problem. Hatch in submissions directed me to a number of authorities on this point. In Aktiebolaget Hassle v Alphapharm Pty Ltd [2002] HCA 59; (2002) 212 CLR 411; (2002) 194 ALR 485; (2002) 77 ALJR 398 the High Court said (at paragraph [21]):

“the warnings in the authorities against the misuse of hindsight are not to be repeated as but prefatory averments and statements of trite law. The danger of such misuse will be particularly acute where what is claimed is a new and inventive combination for the interaction of integers, some or all of which are known.”

54.  I admit with the benefit of having seen what is claimed that the invention appears to relate to a quite simple and clearly combinable grouping of integers. However the evidence falls short in that, while it establishes that each integer taken individually was known to the person skilled in the art, it fails to establish that the person skilled in the art would be directly led to try combining them in the manner claimed in the reasonable expectation that it would solve the identified problem.

In light of the prior art

55.  WorleyParsons relied on five documents to establish the invention lacks an inventive step:

D1 Extract from the Standards of the Tubular Exchanger Manufacturers Association (TEMA), Eighth Edition, 1999 – Figure N-1.2

D2 Singhoffer, E. and Steiner, J., ‘Experiences for the reconstruction of traditional digestion lines with the application of tube digestion elements in the Hungarian Alumina Plants’, Light Metals (1990), 27-33

D3Wischewski, R. et al., ‘Alunorte Global Energy Efficiency’, Light Metals 2011, (2011), 179-184

D4US 3497317 A (TUSCHE) 24 February 1970

D5Driedger, W., ‘Controlling Shell and Tube Exchangers’, Hydrocarbon Processing (1998)

I will discuss the documents in the following order: D3, D1, D4, D5 and D2.

D3

56.  D3 was published in 2011, which is seven years after the undisputed priority date. It therefore does not constitute part of the “prior art base” as it existed before the priority date for the purposes of s 18(b)(ii), nor could it have been ascertained before the priority date for the purposes of s 7(3). WorleyParsons submits that D3 is cited as evidence of prior use, as it discloses heat exchange equipment that was built and operated before the priority date. In the context of inventive step WorleyParsons may have meant that D3 relates to information made publicly available through an act which occurred before the priority date. If that is the case I note that no potentially relevant act has been cited. I am not satisfied D3 forms art I can or should consider for inventive step.

D1

57.  D1 is a table detailing the nomenclature of shell and tube heat exchanger components by reference to drawings. It splits components into three categories: front end stationary head types; shell types; and rear end head types. Of the five listed front end stationary head types three are provided with removable covers. Each of these head types is provided with an inlet requiring an incoming slurry stream to turn at a right angle before entering the tubes. Of the seven listed shell types one is described as a one pass shell. D1 does not elaborate on the relative benefits of any particular component or their relative suitability to particular conditions. While D1 reinforces that single pass heat exchangers and covers are known it provides no hint or motivation to select particular components among others and arrive at the invention.

D4

58.  D4 relates to a method of recovering alumina from bauxite (D4: at column l lines 15-25). The disclosed method comprises passing a suspension of bauxite in caustic soda at super-atmospheric pressure and at greater than one metre per second through an indirectly heated reaction tube (D4: at column 9 lines 3-7). Sections of the tube are heated so that the suspension passes in successive heating steps to a temperature sufficiently high to dissolve the alumina and provide a hot suspension of residuals (D4: at column 9 lines 7-12). The hot suspension is cooled wherein the recovered heat is used in the initial heating steps (D4: at column 9 lines 12-18).  The reaction tube is indirectly heated by providing casings covering tube sections where heating fluid is passed through each casing (D4: at column 3 lines 49-65). Preferably the tube is coiled or bent within the casing such that the length of the tube within the casing is longer than the casing itself (D4: at column 3 lines 49-65).

59.  The method disclosed in D4 overcomes difficulties which made prior attempts to pass bauxite slurry through a heated reaction tube impractical (D4: at column 1 line 59 to column 2 line 47). I note that the reaction tube of D4 may be seen as a form of “double pipe” heat exchanger and D4 does mention the potential use of shell and tube heat exchangers (D4: at column 6 lines 33-40). However, D4 is not directed toward and does not suggest providing an improved shell and tube heat exchange system. Reading D4 in its entirety I am not satisfied it provides motivation leading a person skilled in the art toward a heating system as claimed.

D5

60.  D5 is directed to techniques of controlling a shell and tube heat exchanger. It notes that the heat demands of a particular process and heat content of the two fluids entering the heat exchanger are not constant (D5: at page 3-1 paragraph 2). It further notes that fouling reduces heat transfer through the heat exchanger over time (D5: at page 3-1 paragraph 2). D5 then discusses the immediate considerations for controlling a heat exchanger: determining the measured variable (D5: at page 3-1 paragraph 3) and the manipulated variable (D5: at page 3-1 paragraph 4). D5 then discusses the various ways the process stream or the heating medium stream may be manipulated, such as by throttling or bypassing the process fluid (D5: at page 3-2). While D5 is directed toward controlling existing shell and tube heat exchangers it is not directed toward design or improvement of shell and tube heat exchangers generally. I am not satisfied it provides any motivation to arrive at any particular heating system.  

D2

61.  D2 is a journal article detailing the authors’ experiences reconstructing digestion lines in Hungary. The summary of D2 (provided on page 27) notes that good experiences with “tube digestion” processes prompted experiments replacing autoclaves with single pass tube heat exchangers to recover heat in the digestion process. The results of those experiments led to the following summary recommendation (D2: at page 27 column 1):

“the tube digestion may be utilized in the process of digesting any type of bauxite, while the single pass heat exchanger elements used in the tube digestion may be used for the modernization of the existing digestion lines.”

62.  D2 then reviews the development of the Hungarian digestion system, noting that alumina was first produced in Hungary in 1934 using a batch-wise process (D2: page 27 column 1). Continuous digestion processes were introduced in the 1950s based on existing batch digesters (D2: page 27 column 1). Flash systems were simultaneously developed for recovering heat from the digested slurry and preheating further slurry in indirectly heated autoclaves before digestion (D2: page 27 column 1). Autoclaves were thereafter found to be costly to manufacture and to have a limited heat transfer coefficient (D2: page 27 column 2). Multiple pass heat exchangers were deemed better due to reduced manufacturing costs (D2: page 27 column 2). However, the multiple pass heat exchangers had a tendency for scaling, required frequent cleaning, and had high pressure losses due to turning chambers (D2: page 27 column 2). D2 notes that these good and bad experiences led to the development of single pass heat exchangers eliminating the poor characteristics of the multiple pass heat exchangers (D2: page 27 column 2). This in turn led to the development of the “tube digester” (which I take to be a reactor tube design broadly similar to that disclosed in D4 – D2: page 27 column 2). Fig. 1 of D2 exemplifies this type of tube digester which appears to involve a configuration similar to that of a long single pass heat exchanger unit.

63.  Beginning at page 29 column 1 D2 discusses the reconstruction of heating elements in the digestion sections of the Ajka and Almásfüzitõ alumina plants. The pre-existing heating elements included a desilication part where two six pass heat exchangers heated slurry from 83°C to 100°C prior to entry into the desilication tank (D2: at page 29 column 2). D2 notes that the construction of the pre-existing heat exchangers together with the characteristics of the slurry rendered the equipment susceptible to scaling (D2: at page 29 column 2). During the reconstruction the two pre-existing heat exchangers were replaced with two tube heater elements (D2: at page 30 column 1 and Fig. 6).  The tube heater elements comprised three pieces of 15 m long heating tubes of 3½  inch diameter set within an outer tube of 10¾ inch diameter wherein both ends of the heater are closed (D2: at page 29 column 1).  Replacement of the existing heat exchangers was deemed favourable because (page 29 column 1):

• The worn out, costly heat exchangers and autoclaves might be replaced by cheap, simple tube heat exchanger elements constructed of standard structural elements;
• The tube heater elements require significantly less maintenance than the existing heat exchangers;

·the tube heater elements would be less susceptible to scaling and the resultant loss in heat transfer. 

64.  To minimise space taken up the two heat exchangers were installed on console-type steel structures one above the other (D2: at page 30 column 10). To provide this configuration I would think it likely (but without evidence not necessarily inferable) that the connections between the two heat exchangers would involve sharp turns. Otherwise however, I note that D2 provides no detail as to the configuration of each end of the heat exchanger, other than to say they were closed. D2 does not disclose that either heat exchanger comprised a cover.

65.  Hatch submits that the bauxite slurry discussed in D2 and preheated in the two single pass heat exchangers prior to disilication is a dilute slurry (Boger 2, at paragraph [14]). As a result, Hatch submits, the person skilled in the art would not recognise the disclosure of D2 as being relevant to the problems associated with thick slurries. I note that D2 does not disclose a dilution between desilication and digestion, however Hatch’s submission seems to be at odds with Mr Edwards’ first declaration where, at paragraph [17], he states:

Roach does not distinguish between heating in the Digestion process (which accommodates a dilute slurry) and heating in Pre-Desilication (which accommodates a thick slurry – and which is prior to Digestion).

66.  Accepting Hatch’s submission I would nevertheless not be surprised if, in view of D2’s disclosure of single pass heat exchangers requiring less maintenance and being less susceptible to scaling, the person skilled in the art would consider D2 relevant when solving the identified problem in relation to thick slurries. Professor Boger for example notes that he would not expect scaling issues to change between thick and dilute slurries (Boger 1, at paragraph [60]).

67.  D2 is to my mind the most relevant art cited by WorleyParsons. It provides a suggestion that single pass heat exchangers have benefits over multiple pass heat exchangers in terms of scaling and maintenance. It is therefore possible that D2 provides a motivation to the person skilled in the art to consider replacing multiple pass heat exchangers with single pass heat exchangers in view of those issues. Nevertheless the evidence does not clearly establish that the person skilled in the art would be directly led in view of the identified problem to a heating system having all the features of the invention. While WorleyParsons provides evidence as to what is disclosed in D2 (Thomas 2, at paragraphs [13]-[16], [29]-[31]), it provides no evidence establishing what the person skilled in the art would, having ascertained and understood D2, be directly led to try. Such being the case I am not satisfied that WorleyParsons has discharged its onus by clearly establishing that any claim lacks an inventive step in view of D2.

Ascertainability of D1, D2, D4 and D5.

68.  Hatch has further disputed the ascertainability of D1, D2, D4 or D5. In view of my above conclusions I do not find it necessary to consider this matter.

Manner of Manufacture

69.   WorleyParsons submits that invention claimed is not a manner of manufacture for two reasons.

On the face of the specification

70.  WorleyParsons submitted that all claims of the specification lack the requisite quality of inventiveness on the face of the specification (NV Philips Gloeilampenfabrieken v Mirabella International Pty Ltd [1995] HCA 15; (1995) 183 CLR 655). Reviewing the specification I cannot find any passage which admits or otherwise suggests on its face that the heating system claimed was known in the art, or obvious in view of what was known in the art. As a result I am not satisfied that the heating system claimed lacks the requisite newness on the face of the specification.

New use of a known contrivance

71.  WorleyParsons also submitted that the claims do no more than define the use of known heat exchanger units for a purpose the known properties of the heat exchanger units make them obviously suitable. I note that only claim 22 relates to a method of using the heating system claimed. For the reasons I set out above for inventive step I am not satisfied the heating system claimed was known. As I have set out immediately above I am further not satisfied that the specification admits or otherwise suggests that the heating system claimed was known (AstraZeneca AB v Apotex Pty Ltd [2014] FCAFC 99 at paragraphs [408]-[412]). I am not satisfied that claims 1-21 or 23 relate to a known contrivance or that claim 22 relates to a new use of a known contrivance.

Clarity

72.  A claim is lacking in clarity if a third party could not ascertain whether an act would fall within the scope of the claim (Monsanto Co v Commissioner of Patents (1974) 48 ALJR 59 at 60). A lack of precise definition in claims is not fatal to their validity so long as they provide a workable standard suitable to the intended use (Minnesota Mining & Manufacturing Co v Beiersdorf (Aust) Ltd [1980] HCA 9 at [46]; [1980] HCA 9; (1980) 144 CLR 253 at 274).

73.  WorleyParsons submitted that claim 1 lacks clarity due to inclusion of the phrase: “some turbulence in slurry flow between said units” within the broader phrase:

“the series being connected by an interconnecting pipe or other interconnecting system that provides some turbulence in slurry flow between adjacent said units”

WorleyParsons submits that the degree of turbulence is not defined in the specification and, to the extent that the turbulence is not provided by obvious interconnecting systems, then the claim is unclear.

Addressing WorleyParsons’ first submission – the degree of turbulence required is defined to be “some level”. As I discussed in construing claim 1, I construe the above quoted phrase to mean that the design or action of the interconnecting pipe or system must induce (i.e. introduce or increase) turbulence in the slurry passing through it when compared to the slurry passing through the adjacent heat exchanger units (Boger 1, at paragraphs [64] and [65]; Edwards 1, at paragraph [61]). Any inducement would in my opinion be enough. Addressing WorleyParsons’ second submission – whether a claim allows within its scope obvious as well as non-obvious embodiments or improvements is not relevant to the test for clarity. The relevant test is whether upon consideration one could ascertain whether a specific embodiment would fall within the scope of the claim. Addressing a further point raised by WorleyParsons – whether many pre-existing interconnecting systems would inherently induce some level of turbulence is also not relevant for the same reason. 

74.  WorleyParsons submitted that claim 3 lacks clarity. Claim 3 defines:

“A slurry heating system as claimed in claim 1 or 2 wherein the volume between the at least one said wall and adjacent said removable cover is minimised, to avoid low flow rate areas and attendant settling out of slurry.”

WorleyParsons submitted that the specification is silent on the preferred dimensions of the slurry chambers and what criteria may be used to assess how the volume is to be minimised. While the term “minimised” does not provide a “precise definition” I am satisfied it provides a “workable standard” wherein the configuration of the slurry chamber does not allow for avoidable dead spots which the person skilled in the art would understand creates low flow-rate areas and settling (Roach 1, at paragraph [55]).

75.  WorleyParsons also submitted that claim 4 unnecessarily repeats features of claim 1 and thus lacks succinctness. I accept that claim 4 may be redundant in view of claim 1. However this does not give rise to a lack of clarity in relation to the scope of either of claims 1 or 4 and I would not consider a single redundant claim to render the claim set as a whole so repetitive as to lack succinctness.

Full description

76.   As set out in Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd [2001] HCA 8 at [25]; (2001) 207 CLR 1 at 17 the test for full description is whether:

“the disclosure enable[s] the addressee of the specification to produce something within each claim without new inventions or additions or prolonged study of matters presenting initial difficulty.”

77.  WorleyParsons submits that the specification does not define what is meant by “some turbulence” as used in claim 1. In particular, WorelyParsons submits that the specification fails to teach what level of turbulence is required in the connecting pipes. For the reasons I set out above I am satisfied that level of turbulence required is clear. I am also satisfied that the person skilled in the art would be able to produce an interconnecting system that provides turbulence without new inventions or prolonged study. I am further satisfied that the embodiment shown in the figures exemplifies an interconnecting system that provides some level of turbulence.

78.  WorleyParsons also submits that the specification is silent on how the slurry chambers of claim 3 are to be “minimised”. I am satisfied that the person skilled in the art would be able – in view of the cited goal of avoiding low flow rate areas and attendant settling – to configure a slurry chamber having a minimised volume. I am further satisfied that the embodiment shown in the figures exemplifies a slurry chamber having a minimised volume.

Fair basis

79.     In discussing the test for fair basis, the High Court in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [2004] HCA 58 at [69], 217 CLR 274 at 300 (“Lockwood v Doric”) approved of the words of Gummow J in Rehm Pty Ltd v Websters Security System (International) Pty Ltd (1988) 81 ALR 79 at 95:

“the question is whether there is a real and reasonably clear disclosure in the body of the specification of what is then claimed, so that the alleged invention as claimed is broadly, that is to say in a general sense, described in the body of the specification.”

80.  WorleyParsons submits that claims 1-19 lack fair basis to the extent that the feature of a back pressure control valve controlling pressure within the slurry heating system is not claimed. The basis for WorleyParsons’ submission lies in page 13 lines 24-26 of the specification:

The invention achieves high heat fluxes without risk of slurry boiling in proximity to the inner tube walls (and resulting scale generation).

81.  WorleyParsons submits that the only disclosed means to ensure that slurry boiling is prevented is a back pressure control valve. Therefore, WorleyParsons submits, there is no real and reasonably clear disclosure in the body of the specification of a slurry heating system that lacks any means of avoiding slurry boiling in proximity to the inner tube walls.

82.  As I have discussed above pages 5-8 of the specification provide consistory statements generally consistent with the claims. Most relevantly page 5 lines 18-30 provide a statement consistent with claim 1 and discloses a heating system which does not necessarily require a back pressure control valve. Page 7 lines 13-19 note that the disclosed slurry system preferably has a restrictor or pressure controller to maintain a higher pressure of the slurry within the slurry heating system. Beginning at page 8 a preferred embodiment of the invention is discussed. That preferred embodiment has a backpressure control valve as discussed at page 10 line 16-19 however, as is explicitly noted at page 13 line 30 to page 14 line 2, the invention is not intended to be limited to the preferred embodiment.

83.  Reviewing the entirety of the body of the specification I consider that there is a real and reasonably clear disclosure of a heating system which does not necessarily include a back pressure sensor.

84.  WorleyParsons submits that claim 1 is not fairly based as, although the claim defines “an interconnecting pipe or other interconnecting system”, the specification only describes a single option – being an interconnecting pipe. I would agree that the specification does not describe any preferred embodiments involving anything other than an interconnecting pipe. Nevertheless the description makes it clear that the interconnecting system is not necessarily limited to an interconnecting pipe (at page 5 lines 28-30). 

85.  WorleyParsons have not established that any claim of the specification lacks fair basis.

Utility

86.  The principle is that all within the scope of the claim must be useful if the claim is not to fail for inutility. A claim is bad if it covers means that will not produce the desired result even if a skilful person would know which means to avoid: Norton and Gregory Limited v Jacobs (1937) 54 RPC 271 at 276, Welch Perrin & Co Pty Limited v Worrel [1961] HCA 91; (1961) 106 CLR 588 at 601, Martin Engineering Co v Trison Holdings Pty Ltd (1989) 14 IPR 330 at 337. However, claims should be construed in a common sense way to avoid embodiments understood by the person skilled in the art to be totally impractical and contrived (Austal Ships Pty Ltd v Stena Rederi Aktiebolag [2005] FCA 805, at paragraph [240]).

87.  Similar to its submissions on fair basis WorleyParsons relies on page 13 lines 24-26 of the specification to establish that the promise of the invention includes preventing slurry boiling in proximity to the inner tube walls and that this promise is only fulfilled if the invention includes a backpressure control valve.

88.  I have previously reproduced page 13 lines 16-26 of the specification. I note this passage refers to what “the invention” achieves, in contrast to the passage immediately below it which refers to what “the particular embodiment described herein” achieves (at page 13 lines 27-29). Page 13 lines 16-26 may therefore in isolation be viewed as making promises of the invention generally and not just of the preferred embodiment. It is however important to note that this passage forms part of a broader disclosure to which the person skilled in the art would have regard in determining the promise of the invention.

89.  I have previously referred to the consistory statements which note that a backpressure control valve is a preferred but optional feature of the invention. As stated at page 7 lines 16-19 of the specification:

“Preferably said slurry heating system has a restrictor or pressure controller to maintain a higher pressure of said slurry within said slurry heating system. This arrangement will prevent boiling of said slurry, to prevent scale formation within said inner tubes.”

Similarly at page 10 lines 16-19 (in discussing the preferred embodiment):

“In order to prevent boiling within the inner tubes 30, which would cause scale formation and corrosion, backpressure control for each stream is provided in the form of a valve 90.”

90.  The overall disclosure of the specification is that the restrictor or backpressure controller prevents slurry boiling, and the restrictor or backpressure controller is a preferred but optional feature of the invention. I therefore consider the overall teaching to be that the invention only preferably prevents slurry boiling. I do not think the passage at page 13 lines 16-26 overrides what is taught across the specification generally. 

91.  I have referred previously to the stated object of the invention which is to provide an alternative heating system for indirect heating of thick slurries generally. I have also discussed previously that I consider the implicitly taught object of the invention to be providing a useful indirect heating system in view of the identified problems with the prior art generally. I am not satisfied that WorleyParsons have established that the invention does not achieve this object. WorleyParsons have not established that the invention lacks utility.

Conclusion

1. The opposition has not succeeded on any ground. Subject to an appeal against this decision the application is to proceed to grant.

   Costs

2. Generally costs should follow the event. WorleyParsons requested that Hatch’s delay in filing its summary of submissions be taken into account in determining the award of costs. I note that Hatch were one day late due to a misunderstanding over when their submissions were due. In Mars v Société Des Produits Nestlé S.A. [2014] APO 44 a similar oversight was not considered a sufficient explanation for delay by the delegate of the Commissioner (at paragraphs [211]-[215]). In that case the delegate, in accordance with the discretion provided in reg. 5.20(6), considered it appropriate to make no award of costs. I similarly consider it appropriate to make no award of costs.

3. In accordance with the discretion in reg 5.20(6), I make no award of costs due to the Hatch’s failure to file a summary of submissions within the timeframe set out in reg 5.20(4).

   Rhys Munzel
   Delegate of the Commissioner of Patents