Patents - Geofabrics Ltd v Fiberweb Geosynthetics Ltd

Jane Lambert

Patents Court (David Stone) Geofabrics Ltd v Fiberweb Geosynthetics Ltd [2020] EWHC 444 (Pat) (5 March 2020)

This was an action for patent infringement with a counterclaim  for revocation on grounds of anticipation, obviousness and insufficiency, Mr David Stone, who tried the action and counterclaim, remarked at paragraph [4] of his judgment:

"No new points of law were raised. This is therefore a case which turns entirely on its facts."

The did not prevent the distinguished US intellectual property scholar, Prof. Dennis Crouch, from referring to the judgment as a "UK Patent Law Primer" in his excellent blog Patentlyo (see Dennis Crouch UK Patent Law Primer: Reading through Judge Stone’s New Opinion 9 March 2020 Patentlyo),

Patent in Suit
The patent in suit was European patent (UK) 2 430 238 for a "trackbed liner and related methods". A trackbed is the foundation upon which a railway track is laid. In the above drawing, it is the dark coloured layer numbered 20.  The trackbed is laid on the soil known as "subgrade" which is numbered 22 in the drawing.  In an area with clay soil, the subgrade absorbs moisture when it rains. Such moisture together with particles of clay and silt are forced up into the trackbed when a train runs along the track.   Over time, those clay and silt particles erode the trackbed.  One solution to that problem is to lay a thin layer of sand between the subgrade and the trackbed. The sand slows upward flows of water and traps the silt and clay below the trackbed.  Such a layer of sand is a kind of trackbed liner.  However, it is expensive and inconvenient to lay.  The invention is an alternative.

The invention is described as a geosynthetic trackbed liner made of a "filtration layer" sandwiched between two "support layers."   The support layers are to protect the filtration layer from being pierced or otherwise damaged by the ballast and may have "a relatively high water permeability". At least one filtration layer may be normally impermeable to water but may become permeable upon the application of sufficiently high pressure to the surface of the filtration layer.  That would happen when a train passes over the track.  The layer would recover its permeability as soon as the train has passed as the pressure on the layer is released (see the abstract of the patent and claims). 

The Action
The patentee Geofabrics Ltd ("Geofabrics") complained that the defendant's product Hydrotex Rail Geosynthetic infringed its patent.  To save costs and time, paragraph 6.1 of the Part 63 Practice Direction provides:

"6.1 Standard disclosure does not require the disclosure of documents that relate to –
(1) the infringement of a patent by a product or process where –
(a) not less than 21 days before the date for service of a list of documents the defendant notifies the claimant and any other party of the defendant’s intention to serve–
i) full particulars of the product or process alleged to infringe; and
ii) any necessary drawings or other illustrations; and
(b) on or before the date for service the defendant serves on the claimant and any other party the documents referred to in paragraph 6.1(1)(a)."

The defendant, Fiberweb Geosynthetics Ltd. ("Fiberweb") served the following amended particulars on the second day of the trial:

"4. Hydrotex 2 comprises a five component laminated structure. It is produced in rolls of varying lengths and widths. It is intended for use as a railway trackbed liner.
5. The innermost layer in the laminated structure is a bi-component, 80gsm, 85% polypropylene core, 15% polyethylene sheath spun-bonded, non-woven sheet material (A). This layer is calendered with a hot roller to reduce the pore size to that required for clay particle filtration. The mean pore size is 4 microns around a standard distribution with a typical range of pore sizes from 0.06 to 7.0 microns.
6. On either side of the innermost layer, an intermediate layer comprises a 30gsm high density polyethylene spun-bonded, non-woven material (B) – Aspun 6834.
7. An outermost layer on opposite sides of the intermediate layers comprises an 800gsm polypropylene, non-woven, needle punched material (C).
8. The innermost layer A is glued to the intermediate layer B by means of an EVA hot melt adhesive powder (D) to form a sub-assembly.
9. The outermost layer (C) is flame laminated on to opposite sides of the sub-assembly.
10. The innermost layer (A) is permeable to liquid water both by itself and when assembled into the completed product. The completed product, when tested in accordance to ISO 11058, is permeable to liquid water in the absence of the load equivalent to of a vehicle acting on the trackbed and under the load equivalent to of a vehicle acting on the trackbed.
10A. Outside this litigation the Defendant has no knowledge of the permeability characteristics of its product in use as a trackbed (i.e. other than tests made in accordance with ISO 11058).
10B. The defendant believes that in use water is never permitted to pass upwardly through the filtrate layer because instead it passes laterally out through the support layer.
11. The intermediate and outmost layers B, C are liquid water permeable."

The Defence and Counterclaim
Fiberweb denied infringement and the validity of the patent.  It alleged that patent number WO 95/04190 granted to David John Hoare and others entitled "Improvements in or relating to Pavements" ("Hoare") had anticipated the invention. Alternatively, it argued that the invention was obvious over Hoare and British patent GB 2 356 880 for "Rail support structures and geosynthetics" that had been invented by Anthony Jay ("Jay"). Fiberweb also contended that the patent was bad for insufficiency.

Construing the Patent
Mr Stone's first task was to construe the patent.  He directed himself as follows:

"[67] The parties agreed that patent claims are to be construed purposively: I must read the Patent through the eyes of the skilled addressee and identify what the words of the claim would mean in their context to such an addressee. The context includes the very purpose for which the document exists – to describe and claim an invention. Both parties referred me to the judgment of Lord Kitchin JSC in Icescape Limited v Ice-World International BV [2018] EWCA Civ 2219. The Claimant also relied on what was said to be the "standard drafting practice for there to be a hierarchy of claims", such that it was submitted that I should conclude that an earlier claim is wider than a later subsidiary claim.
[68] I was also referred by the Claimant's counsel to Milliken Denmark AS v Walk Off Mats Limited and Another [1996] FSR 292 per Jacob J (as he then was) as an example of the correct approach to interpretation of a claim which required the back of a floor covering to be "water impermeable in normal use". However, counsel for the Claimant also conceded that the judge's findings of fact in Milliken are not binding on me as to the proper interpretation of the meaning of the Patent in this case, useful though Milliken may be in demonstrating the proper approach to construction (albeit, as the Defendant's counsel pointed out, there have been several authoritative statements of the law since that judgment).
[69] In any event, counsel for both parties agreed that, in the end, construction of the Patent is a matter for the court, putting on the mantle of the skilled addressee."

It was common ground that all aspects of the case stood or fell with Claim 1 which was broken into integers as follows:

"A trackbed liner comprising:
1.1 an upper support layer;
1.2 a lower support layer; and
1.3 at least one filtration layer of a material having a plurality of pores
1.4 and which is normally impermeable to liquid water, that is in the absence of the load of a vehicle acting on the trackbed,
1.5 the filtration layer located between the upper and lower support layers;
1.6 in which the pores of the filtration layer are dimensioned so that, in use and under load of a vehicle acting on the trackbed, the filtration layer
- 1.6.1 permits passage of liquid water upwardly therethrough but
- 1.6.2 restricts the passage of solids materials, so as to restrict pumping erosion of material located beneath the liner."

There were two issues on construction.  One was the meaning of the phrase "normally impermeable to liquid water, that is in the absence of the load of a vehicle acting on the trackbed".  The other was whether or not there was in the patent in suit an implicit limitation in claim 1 to a pore size of 2µm or less.

The deputy judge directed himself as follows:

"[77] The parties agreed on the law on novelty: I was referred to the judgment of Sachs LJ in General Tire & Rubber Co v Firestone Tyre & Rubber Co Limited [1972] RPC 457 at 486:

'To anticipate the patentee's claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented: Flour Oxidizing Co Ltd v Carr & Co Ltd (1908) 25 RPC 428 at 457, line 34, approved in BTH Co Ltd v Metropolitan Vickers Electrical Co Ltd (1928) 45 RPC 1 at 24, line 1). 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 patentees."'

[78] I was also reminded of Lord Hoffman's speech in H Lundbeck A/S v Generics (UK) Limited [2008] EWCA Civ 311 at paragraph 9 that the prior art relied on must "disclose the claimed invention and (together with the CGK) enable the ordinary skilled person to perform it". In this context, the word "disclose" means to disclose the subject matter which, if performed, would necessarily result in infringement of the patent: Synthon BV v SmithKline Beecham plc [2006] RPC 10 at paragraph 22, see also Takeda UK Limited v F. Hoffman – La Roche AG [2019] EWHC 1911 (Pat) at paragraphs 118 to 134 per Birss J."
    It is worth noting that Prof. Crouch noted in his article that our novelty law is" substantially parallel to that of the U.S., although with a somewhat heightened enablement requirement."  He referred to Mr Stone's quotation from Lord Justice Sachs's judgment in General Tire & Rubber and added:  "More recently, UK courts have noted that an anticipatory references must both disclose the claimed invention as and also “enable the ordinary skilled person to perform it. Synthon BV v SmithKline Beecham plc [2006] RPC 10 (Lord Hoffman)"

    The deputy judge construed Hoare and compared it to the patent.  He concluded that Hoare had not anticipated the patent in suit for the following reasons:

    "(a) as the Claimant pointed out, the invention described in Hoare, even including the reference to Gore, does not read onto the structure described in the Patent: Hoare does not describe the use of a filter layer, nor does it reference a layer which is normally impermeable to water but allows the upwards passage of water under the load of a train. Hoare does not address these concepts at all;
    (b) Hoare directs the skilled addressee to a choice of three lower layers – of which the Defendant relies on type (b). This is a 3-layer sandwich construction, but Hoare directs that the middle layer must be substantially impermeable to liquid water and Professor Ingold gave no clear answer as to why the skilled addressee would ignore this requirement, even taking into account example 10 from Gore. Even so, if the skilled addressee considering Hoare wanted a water permeable layer, Hoare would direct her/him to a type (a) material with large perforations or slits in it, on which the Defendant expressly did not rely."

    The law on obviousness was not in dispute.  Mr Stone was referred to paragraphs [52] to [73] of Lord Hodge's judgment in Actavis Group PTC EHF and others v ICOS Corporation and another  [2019] Bus LR 1318, [2019] UKSC 15 and paragraph [23] of Lord Justice Jacob's in  Pozzoli SpA v BDMO SA [2007] EWCA Civ 558:

    "(1) (a) Identify the notional [skilled addressee]; (b) Identify the relevant common general knowledge of that person;
    (2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
    (3) Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed;
    (4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?"

    He noted that the fourth Pozzoli question is the statutory test – the first three tasks are means of disciplining the court's approach to the fourth question. He was reminded that hindsight must be avoided: per Oliver LJ in Windsurfing International Inc v Tabur Marine (Great Britain) Limited [1985] RPC 59 and that Non-Drip v Strangers [1943] 60 RPC 135 and British Westinghouse v Braulik (1910) 27 RPC 209  remain good law (per Technip France SA's Patent [2004] RPC 46).

    Quoting Lord Justice Jacob's judgment in Pozzoli, Prof. Crouch noted that the Windsurfing-Pozzoli test parallels the Graham analysis.  In Graham v. John Deere Co., 383 U.S. 1 (1966) the US Supreme Court  posed the following questions  to resolve the issue of obviousness:
    • What is the scope and content of the prior art?
    • What is the level of ordinary skill in the art~ and
    • What are the differences between the claimed invention and the prior art?
    There may also be "secondary considerations" that can also serve as evidence of non-obviousness.  Another difference between obviousness here and in the USA is that an invention is deemed not to be obvious "if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art by virtue only of section 2 (2) (and disregarding section 2 (3) above)."  Professor Crouch added:

    "Note here that the UK statute limits obviousness analysis only to publicly-available prior art while secret prior art (such as prior filed applications) are available only for novelty analysis."

    For a while, I could not understand Prof. Crouch's point. Then I realized that he must be referring to the words "and disregarding section 2 (3) above" from s.3.  For an English lawyer, the exclusion of matter that the skilled addressee could not possibly know seems plain common sense. That is because the criterion in this country is not what is obvious having regard to the prior art but what would be obvious to a person skilled in the art. A skilled addressee is not expected to know everything in the prior art.  Only matter that is common general knowledge to all skilled addressees.  That can only be matter in the public domain.  If a different standard applies on the other side of the Atlantic it may be that the Graham analysis and the Windsurfing-Pozzoli test are not all that similar after all

    At paragraph [52] of his judgment, Mr Stone recorded that the parties had agreed that the skilled addressee would be:

    "A professionally qualified geotechnical engineer with several years' post graduate experience and knowledge of railway trackbed design and of the availability, design, manufacture and performance of geosynthetic materials."

    They also agreed at [53] that the common general knowledge would be:

    "(a) The recognised problem of pumping erosion including that it is caused by the passage of a train over subgrade which is wet and which as a result forms a slurry.
    (b) The conventional way of making a trackbed utilising a layer of sand to combat pumping erosion.
    (c) The time and cost of installing an appropriate layer of sand.
    (d) The potential to use geosynthetics in rail applications.
    (e) The fact that geosynthetics can be permeable geotextiles or impermeable geomembranes.
    (f) The combination of geosynthetic layers to form a geocomposite.
    (g) The use of geosynthetics in a trackbed liner for separation, waterproofing and reinforcement.
    (h) Knowledge of the concepts of water entry pressure (WEP), pore size and permeability and how to vary them in geotextiles.
    (i) Knowledge of EN11058 as an established method of testing the permeability of geotextiles.
    (j) Darcy's equation and its application to water movement.
    (k) Characteristics of soils, their particle size distribution and its effects. This would include the particle size ranges of clay, silt, sand and gravel; that clay and silt are cohesive; that water cannot drain from them rapidly even under load; and that when it does so it can transport with it fine soil particles.
    (l) That clay particles suspended in water are transported easily in the water column, and in particular more easily than silt particles.
    (m) Knowledge of Network Rail specification RT/CE/S/071 Design of Earthworks and Earthworks Remediations. The skilled person would have access to a copy and refer to it as necessary.
    (n) 1986 Paper by D. J. Ayres ("Ayres' Paper") entitled "Geotextiles or Geomembranes in Track? British Railways' Experience" which includes the following:
    (i) A discussion of the well-known problem of pumping erosion and the use of sand (page 131).
    (ii) British Railways ("BR") [the predecessor of Network Rail] had for some years used a standard design with a geomembrane placed in the middle of the layer of sand with success (pages 131/132).
    (iii) That despite optimistic claims, BR had found that geotextiles alone would not solve the problem. Slurry can pass through them. Geotextiles are "useless" as a permanent replacement for sand, but their delaying effect might be reviewed (page 132 and 135 to 138).
    (iv) "No geotextile commercially available in the world has been found which can prevent the passage of clay and silt particulars under dynamic loading." (page 141)."

    Applying the Windsurfing-Pozzoli test, the deputy judge concluded at [103]:

    "In my judgment, a skilled addressee of nature agreed between the parties, equipped with the CGK agreed between the parties, would not consider it obvious to take these steps. The Patent is not obvious over Hoare/Gore. Hoare addresses the known problem of pumping erosion, but proposes a very different solution."   

    As for Jay, Mr Stone said at [112]:

    "Jay is all about using an impermeable layer, which Jay accepts will not avoid pumping erosion. I accept that the skilled addressee, who wishes to avoid pumping erosion, will look for alternatives. Permeable membranes were known. But it is by no means clear to me that a skilled addressee equipped with the CGK would:
    (a) replace an impermeable membrane with a permeable one;
    (b) introduce a filtering element when none is hinted at in Jay; and
    (c) choose a geomembrane that operated under the load of a train – that is, it would allow water to pass up through it (whilst being filtered) only under the pressure of the load of a train, and not under the pressure of the tracks and ballast in the absence of a train."

    The deputy judge referred to s.72 (1) (c) of the Patents Act 1977 and considered the various types of insufficiency, namely:-
    • Classical insufficiency: where the patent does not give sufficient directions to enable a product to be made without undue burden (see Eli Lilly and Company v Human Genome Sciences Inc [2008] EWHC 1903);
    • Uncertainty: where the patent is insufficient because it lacks clarity and/or is ambiguous; and
    • Implausibility which Prof Crouch discusses below.
    Prof, Crouch considered each type of insufficiency and concluded that:
    • Uncertainty was basically the same as claim indefiniteness in the U.S. — requiring undue effort to understand the scope of the claims.
    • Classical insufficiency was parallel to enablement in US law — the specification must enable a person skilled in the art to perform the invention without undue burden. 
    • The plausibility doctrine has some flavours of US utility doctrine. He added: "Normally, plausibility will be assumed. However, courts have raised suspicion in situations where an inventor could easily file many patents based upon pure speculation of success. One example of this might be a new medical use of a known drug (“second medical use claim”). In that situation, the UK Courts require “some disclosure as to how or why the known product can be expected to work in the new application.”
    At paragraph [54] Mr Stone listed the four issues which were not dealt with in the patent:

    "(a) there is no scientific theory in the Patent which explains how it is to be made to work (and no theory relating to clogging or blocking);
    (b) there are no data in the Patent which tell the skilled person if a product was made which worked;
    (c) no data are provided in the Patent to enable the skilled addressee to form a view on whether the invention in the Patent works or not; and
    (d) the skilled person cannot in any event work out whether or not a product infringes in situ without more data about the site at which it was laid".

    He rejected the uncertainty argument at [126]:

    "In my judgment, the skilled addressee is able to ascertain the boundary of the invention claimed in the Patent. In doing so, as I have noted above, the skilled addressee will be aware of the context – that these are industrial barriers to be placed between rough aggregate and clay subgrade. These are conditions which are very rugged, and the skilled addressee will interpret "normally impermeable" accordingly. The skilled addressee will simply not care whether the product works perfectly – ie, no measurable water passes downwards through the geomembrane and no measurable clay fines pass upwards through the geomembrane. The skilled addressee is concerned to overcome the well-known problem of pumping erosion – she/he will not be interested in detailed or accurate measurements of tiny amounts of either water or clay fines."

    He concluded at [127] that there was nothing uncertain about Claim 1 and that the skilled addressee would know what tests to apply to determine infringement.

    Similarly, he dismissed the classical insufficiency at [133]:

    "I have also found that clogging/blocking was one possible explanation put forward by Mr Sangster for what, both parties conceded, was a very complex interplay of forces beneath the geotextile. I accept the Claimant's submission that I do not need to establish exactly how a product made to the Patent works in order to find that it is sufficient. I have found that a product made to the Patent (Hydrotex) does work and can be tested. The classical insufficiency case therefore fails."

    As for implausibility, the deputy judge referred to Lord Sumption's remark in Warner-Lambert that a patent for a new product will almost always be plausible.  This was not a second medical use claim where the applicant had no idea whether the invention would work or not.

    Having construed the patent and after referring to the Supreme Court's judgment in Actavis Mr Stone considered whether Hydrotex infringed the patent on normal construction and found that it did.  If he were wrong, it would certainly infringe in a similar way.

    The deputy judge concluded at [154]:

    "The Patent is not anticipated by Hoare (including Gore). The Patent is not obvious over Hoare (including Gore) or over Jay. The Patent is not insufficient. Hydrotex infringes the Patent."
      Anyone wishing to discuss this case or patents generally may call me on 020 7404 5252 during office hours or send me a message through my contact form.


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