Patents - Infringement and Revocation: Glass and others v Freysinnet Ltd.

In Glass and Others v  Freyssinet Ltd [2015] EWHC 2972 (IPEC) the inventors of a treatment process for concrete sued Freysinnet Ltd. ("Freysinnet") for infringement of their patent in the Intellectual Property Enterprise Court. Freysinnet counterclaimed for revocation of the patent on grounds of anticipation and obviousness. The action and counterclaim came on before His Honour Judge Hacon.

The Invention

The technical problem that the patented invention addressed was summarized by Judge Hacon at paragraph [3] of his judgment:
"Reinforced concrete is concrete containing bars made from another material, usually steel, which confer added strength (known as 'rebars'). The strength in compression of the concrete is complemented by the higher tensile strength and ductility of steel. Calcium hydroxide and alkaline salts within the concrete combine to create an iron oxide film on the surface of the steel which protects it from corrosion. That film may be broken down, typically by atmospheric carbon dioxide or carbon dioxide dissolving in rain water, creating carbonic acid, which enters the pores of the concrete and reacts with the iron oxide layer. Alternatively chloride ions from de-icing salts or seawater may destabilise the layer. Corrosion of the steel is then liable to occur. Rust created by corrosion occupies a volume greater than the steel it replaces, creating an expansive force which leads to cracking and spalling (surface failure leading to flaking) of the concrete. The structural capacity of the concrete accordingly suffers. In addition the cracks allow further ingress of water, accelerating the deterioration."
A number of solutions were known at the time of the application for the patent, one of which was cathodic protection whereby an electrochemical cell is created within the concrete in which the rebar acts as a cathode and thereby inhibits corrosion.  Two types of electrochemical cells were known. In one a direct current is used to create an impressed current. An anode is located in the concrete and connected to the positive terminal of the current supply. The rebars are connected to the negative terminal so that they become cathodes. The concrete serves as the electrolyte. This is known as an impressed current cathodicrprotection system. The other relies on the difference in electrode potential between metals. Where, for instance, zinc and steel are electrically connected and both contained in an electrolyte, an electrochemical potential is created between them so that current will flow. The zinc will form the anode and the steel the cathode. The zinc anode will then corrode preferentially. The zinc forms what is known as a sacrificial or galvanic anode. The metal to be protected must be less electrochemically active than the metal which is to be sacrificed. Using the traditional language of chemists, it must be a more 'noble' metal than that of the sacrificial anode. That arrangement is known as a sacrificial or galvanic cathodic protection system.

The patented invention was a hybrid system for protecting steel rebars in reinforced concrete, combining the impressed current and sacrificial anode techniques. There is an initial impressed current phase in which an external source of direct current is used with the steel serving as the cathode and another less noble metal as the anode. This is followed by a longer sacrificial phase in which the external current potential is no longer applied but the difference in electrode potential between the metals sets up a flow of a current and, thus, a sacrificial system to protect the steel.

The Disputed Claims

The claims  alleged to have been infringed were as follows:
"Claim 1: A method of protecting steel in concrete comprising an initial temporary high impressed current electrochemical treatment using a source of DC power to improve the environment at the steel followed by a long term low current preventative treatment to inhibit steel corrosion initiation where the same anode is used in both treatments and the anode at least in part consists of a sacrificial metal that undergoes sacrificial metal dissolution as its main anodic reaction and the anode is embedded in a porous material in contact with the concrete."
"Claim 12: A method as claimed in claim 11 where the sacrificial metal is formed around an inert impressed current anode."
Freysinnet alleged that claim 12 lacked novelty but not claim 1. However, it contended that both claims were obvious having regard to the prior art.

Prior Art

Freyssinet  cited UK Patent Application No. 2 239 591 ("Fosroc 1"), PCT Application, publication no. WO 00/26439 ("Fosroc 2"), PCT Application, publication no. WO 01/71063 A1 ("Enser") and common general knowledge in support of its counterclaim.


The judge said at paragraph [40] that
"The prior art must both (a) disclose subject-matter which, if performed, would necessarily result in an infringement of the patent and (b) enable the invention in the sense that the skilled person would have been able to perform the invention, see Smithkline Beecham plc's (Paroxetine Methanesulfonate) Patent  [2005] UKHL 59, [2006] 1 All ER 685, [2006] RPC 10."
It is not enough to show that the patented invention was anticipated in a mosaic of previous inventions although that may be relevant to a claim that the invention lacked an inventive step.  An issue in this case was whether any of the previous inventions actually disclosed the patented invention.  As His Honour put it at [41]:
"A point of law which arises in the present case concerns what one of the cited items of the prior art discloses. Specifically, to what extent are alternative disclosures listed in, or otherwise derivable from, a single item of prior art each separately disclosed for the purposes of the law on novelty?"
After referring to Mr Justice Pumfrey's decision in Ranbaxy UK Ltd and another v Warner-Lambert Company [2005] EWHC 2142 (Pat), (2006) 29(1) IPD 29005, [2005] EWHC 2142 (Patents), [2006] FSR 14 which I noted in IP Case Law Update - Patents: Ranbaxy UK Ltd and another v Warner-Lambert Co. [2005] EWHC 2142 (Patents) (12 Oct 2005) 13 Oct 2005 Judge Hacon said at paragraph [49]:
"I think that an important criterion in determining whether a combination from within a single item of prior art deprives a subsequent claim to that combination of novelty is whether there is clear and unambiguous teaching, taking the prior art as a whole, that the relevant combination can be made. Absent such a clear and unambiguous indication, the prior art will not disclose subject-matter which, if (comprehensively) performed, would necessarily result in an infringement of the patent in suit (see Smithkline Beecham's Patent at [22])."
 The closest item of prior art to the patent in suit was Fosroc 1. One of the essential features of claim 12 was a sacrificial metal element as referred to in the previous claims. The specification of Fosroc 1 suggested that the invention could work without such an element:
"The anode may be provided with a non sacrificial conductor to maintain electrical continuity through the anode. When the anode is an impressed current anode such as a mixed metal oxide coated titanium, the non sacrificial conductor may be a titanium wire. When the anode is a sacrificial anode, such as zinc, the non sacrificial conducted may be a steel wire."
For that reason alone Fosroc 1 could not have anticipated claim 12.


The judge directed himself to Lord Justice Oliver's test in Windsurfing  as restated by Lord Justice Jacob in Pozzoli Spa v BDMO SA and Another  [2007] BusLR D117, [2007] EWCA Civ 588, [2007] FSR 37 at paragraph [23]:
"(1) (a) Identify the notional "person skilled in the art"
      (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 also considered Lord Justice Kitchin's guidance in  Medimmune Ltd v Novartis Pharmaceuticals UK Ltd and Others [2013] RPC 27, [2012] EWCA Civ 1234 1234 (10 Oct 2012) on step 4 between paragraphs [89] and [93]:
"[89] It is step (4) which is key and requires the court to consider whether the claimed invention was obvious to the skilled but unimaginative addressee at the priority date. He is equipped with the common general knowledge; he is deemed to have read or listened to the prior disclosure properly and in that sense with interest; he has the prejudices, preferences and attitudes of those in the field; and he has no knowledge of the invention.
[90]  One of the matters which it may be appropriate to take into account is whether it was obvious to try a particular route to an improved product or process. There may be no certainty of success but the skilled person might nevertheless assess the prospects of success as being sufficient to warrant a trial. In some circumstances this may be sufficient to render an invention obvious. On the other hand, there are areas of technology such as pharmaceuticals and biotechnology which are heavily dependent on research, and where workers are faced with many possible avenues to explore but have little idea if any one of them will prove fruitful. Nevertheless they do pursue them in the hope that they will find new and useful products. They plainly would not carry out this work if the prospects of success were so low as not to make them worthwhile. But denial of patent protection in all such cases would act as a significant deterrent to research.
[91] For these reasons, the judgments of the courts in England and Wales and of the Boards of Appeal of the EPO often reveal an enquiry by the tribunal into whether it was obvious to pursue a particular approach with a reasonable or fair expectation of success as opposed to a hope to succeed. Whether a route has a reasonable or fair prospect of success will depend upon all the circumstances including an ability rationally to predict a successful outcome, how long the project may take, the extent to which the field is unexplored, the complexity or otherwise of any necessary experiments, whether such experiments can be performed by routine means and whether the skilled person will have to make a series of correct decisions along the way. Lord Hoffmann summarised the position in this way in Conor at [42]:
"In the Court of Appeal, Jacob LJ dealt comprehensively with the question of when an invention could be considered obvious on the ground that it was obvious to try. He correctly summarised the authorities, starting with the judgment of Diplock LJ in Johns-Manville Corporation's Patent [1967] RPC 479, by saying that the notion of something being obvious to try was useful only in a case where there was a fair expectation of success. How much of an expectation would be needed depended on the particular facts of the case.'
[92] Moreover, whether a route is obvious to try is only one of many considerations which it may be appropriate for the court to take into account. In Generics (UK) Ltd v H Lundbeck, [2008] EWCA Civ 311, [2008] RPC 19, at [24] and in Conor [2008] UKHL 49, [2008] RPC 28 at [42], Lord Hoffmann approved this statement of principle which I made at first instance in Lundbeck:
'The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success.'
[93] Ultimately the court has to evaluate all the relevant circumstances in order to answer a single and relatively simple question of fact: was it obvious to the skilled but unimaginative addressee to make a product or carry out a process falling within the claim. As Aldous LJ said inNorton Healthcare v Beecham Group Plc (unreported, 19 June 1997):
'Each case depends upon the invention and the surrounding facts. No formula can be substituted for the words of the statute. In every case the Court has to weigh up the evidence and decide whether the invention was obvious. This is the statutory task.'"
The difference between claim 12 and Fosroc 1 is that the latter does not disclose an anode of a metal less noble than steel with a connector made either of titanium or carbon fibre. The dispute came down to whether it was obvious to the skilled person at the priority date to use a zinc anode in a Fosroc 1 assembly with a titanium connector.  Both sides' experts agreed that it would have been obvious to use a titanium connector with a zinc anode because unlike steel it did not corrode and titanium crimped connections were known to be convenient to use. In the light of that evidence Judge Hacon concluded that the invention claimed in claim 12  lacked an inventive step relative to Fosroc 1. He made a similar finding on more or less the same grounds in respect of Fosroc 2 but not in respect of Enser or common general knowledge.

The case for obviousness in respect of claim 1 in the light of Fosroc 1 and 2 depended on a construction of the claim that the judge had rejected. The case in respect of Enser was not pleaded to the judge's satisfaction and he disregarded it.


An unusual feature of this case was that there was no evidence of any disposal by Freyssinet of an infringing anode in the United Kingdom. At trial the issues were whether
  1. there has been an offer to dispose of an anode falling with claim 12 of the patent in this country and 
  2. Freyssinet offered the method of claim 1 for use in the UK when Freyssinet knew, or it was obvious to a reasonable person in the circumstances, that the use of the method in the UK without the claimants' consent would be an infringement of their patent.
Freysinet did issue a data sheet that had been prepared in the course of negotiations with the claimants for the right to distribute the patented system but those negotiations came to nought.  The judge held that neither claim 1 nor claim 12 had been infringed by those data sheets. Freyssinet did admit that another of its data sheets would have infringed claim 12 had it been valid but the judge had held that it was not.


Judge Hacon held that claim 1 was valid but had not been infringed and that claim 12 would have been infringed had it been valid.

This is quite a meaty case for IPEC. If anyone wants to discuss it with me or patent law in general he or she should call me on 020 7404 5252 during office hours or contact me through this form.


Anonymous said…
The following statement in the blog is false:
"Both sides' experts agreed that it would have been obvious to use a titanium connector with a zinc anode because unlike steel it did not corrode and titanium crimped connections were known to be convenient to use."

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