Posted: May 20th, 2020
Geofabrics Limited v Fiberweb Geosynthetics Limited  EWHC 444 (Par) (5 March 2020)
In this judgment Mr. David Stone (sitting as a Deputy High Court Judge) held that Geofabrics Limited’s patent entitled “trackbed liner and related methods” is valid and infringed by Fiberweb Geosynthetics Limited’s product, Hydrotex 2.0.
Geofabrics Limited (“Geofabrics”) is the proprietor of the European Patent (UK) 2 430 238 (“EP’238”). EP’238 concerns a solution to the problem of pumping erosion – the gradual removal of clay and silt particles from the trackbed onto the track caused by the heavy load of trains pushing water and other particles out from within the clay. Geofabrics manufactures Tracktex, a geotextile fabric used to line railway tracks and prevent pumping erosion occurring.
Fiberweb Geosynthetics Limited (“Fiberweb”) manufacture Hydrotex 2.0 (“Hydrotex”), another geotextile fabric, which is used by Network Rail in the United Kingdom to prevent pumping erosion. Geofabrics sued Fiberweb, alleging that Hydrotex infringes EP’238. Fiberweb denied infringement and counterclaimed for invalidity of the patent on the grounds of lack of novelty, obviousness and insufficiency.
Validity of the Patent
EP’238 claims a geosynthetic trackbed liner made of a “filtration layer” sandwiched between two “support layers”, which can be used to prevent the problem of pumping erosion. It consists of a filtration layer made of a material that is normally impermeable to water, which becomes permeable on application of a sufficiently high pressure, such as when the train passes over the track. The filtration layer should restrict the passage of any solid materials.
Fiberweb relied on one prior art citation (“Hoare”) for lack of novelty. This was rejected on the basis that it did not contain clear enough instructions to allow the skilled person, using the common general knowledge, to perform the invention. The law of novelty requires the inventor to have “planted his flag at the precise destination” (General Tire & Rubber Co v Firestone Tyre & Rubber Co Limited  RPC) and the judge did not consider that the prior art disclosed the precise information that would lead to the invention inevitably being performed.
Both Hoare and a further prior art citation (“Jay”) were pleaded for obviousness. The argument of obviousness over Hoare was rejected, with the judge concluding that the inventive step of the patent, including having a layer that was impermeable under the load of the train, would not be obvious over the prior art.
Jay described a geosynthetic solution to pumping erosion, using a geomembrane with an impermeable layer that prevents water from moving upwards. Further experiments showed that this technique did not prevent pumping erosion, but instead caused the silt and clay particles to be dispersed either side of the track. The judge found that EP’238 would not be obvious over this prior art, as there were multiple modifications to the product required to resolve the problem of pumping erosion.
Insufficiency arguments were made on the basis of uncertainty, plausibility and classical insufficiency, and were all rejected the judge. The claims were not considered uncertain and the court noted Lord Sumption’s remarks in Warner-Lambert that a patent for a new product or process is “almost always plausible”.
The main classical insufficiency argument was that EP’986 has no teaching as to how to make a trackbed liner which does not have substantially lateral flow when under the load of a train. Fiberweb put forward mathematical models that demonstrated that the water would always move laterally out of the material. The judge rejected these arguments based on, amongst other factors, the existence of two products (Hydrotex and Tracktex) that solved pumping erosion without complaints from train companies. He accepted Geofabric’s submissions that it is not necessary to establish exactly how a product made to a patent works to find the patent sufficient. It was enough that products had been made and those could be tested.
Non Equivalence Infringement
The first issue was whether Hydrotex satisfied the claim requirement for upward movement of water to filter clay particles. There were edits to Fiberweb’s Product and Process Description (PPD) to state that Fiberweb understood that the function of Hydrotex never permits water to move upwards. Cross-examination of the Product Development Manager, however, revealed that there was no experimental evidence to support this. It was, therefore, accepted by the judge that the unamended PPD should be accepted as the accurate description of Hydrotex and this requirement was satisfied.
Fiberweb also ran a non-infringement construction argument, namely a filtration layer in accordance with claim 1 required a certain pore size and Hydrodex did not meet that requirement. This was rejected by the judge on the basis that the specification used the word “may” rather than “must” in relation to the pore size limitation.
The key issue revolved around the meaning of “normally impermeable to liquid water”, with Fiberweb arguing that this should be judged by taking into account the permeability of the material when under the weight of the track and ballast (the rock layer on the track). It was held that this was not appropriate, as the experts had provided evidence that in these circumstances water would just run off either side of the ballast. Fiberweb also put forward evidence that, due to the uneven nature of the track, pools of water referred to as “bathtubs” often form. Fiberweb argued that the material is not impermeable to these bathtubs of water, so could not be considered “normally impermeable to liquid water”. This argument was rejected on the basis that, across the length of the whole track, the number of bathtubs would be small and so the majority of the material would be impermeable.
For these reasons the judge found Hydrotex to infringe EP’238.
The judge went on to consider infringement by equivalence, in case he was found to be wrong on non-equivalence infringement. Fiberweb submitted that Geofabric’s claim for infringement based on equivalence should not be considered because they had not been pleaded. This was rejected by the judge, finding that as “infringement” had been pleaded, it covered both “normal” and “equivalence” infringement. The case of Illumina Inc and Ors v Premaitha Health Plc and Ors  EWHC 2930 (pat) was distinguished on the basis that there was sufficient evidence put forward in this case to consider and make findings on equivalence.
The Supreme Court Actavis UK Ltd v Eli Lily equivalence test (as also discussed in Icescape by Lord Kitchin) was applied, with the judge concluding that Hydrotex does achieve substantially the same result in substantially the same way. The judge found that the final limb of the test, that refers to whether the patentee intended that literal compliance with the wording of the claim was necessary, should also be answered in the negative. In this case, the concept of “normal” permeability had been discussed at length and it was found that this would be the level of permeability that would be expected of a track liner.
Hydrotex would therefore also infringe by equivalence.
The Court held that the patent is not anticipated by or obvious over the prior art and is sufficient. Therefore, the patent is valid and is also infringed by Fiberweb’s Hydrotex product.
The full judgment can be accessed here.
Headnote: Jennifer O’Kane and Amy Crouch, Simmons & Simmons LLP