First published by EPLAW on 26 July 2021.
The UK Court of Appeal dismissed an appeal by Fiberweb against a finding of Mr David Stone (sitting as a Deputy High Court Judge) that Geofabric’s patent relating to trackbed liners for railways was valid and infringed.
The patent related to liners aimed at limiting erosion of the trackbed of railway tracks caused by the repeated and rapid application of pressure from the passage of trains causing water, clay, and silt particles to be squeezed out of the trackbed. Such liners work by being permeable to water, but not solid particles, under the pressure of a passing train. The key integer of the patent required the liner to be: “normally impermeable by liquid water, that is in the absence of the load of a vehicle acting on the trackbed”.
Grounds of Appeal
Fiberweb was granted permission to appeal to the Court of Appeal on two grounds: (i) Mr Stone’s construction of “normally impermeable”; and (ii) his finding of novelty over WO 95/04190 (Hoare).
Fiberweb argued that despite the inclusion of a definition in the claim of normal conditions (i.e. “in the absence of the load of a vehicle acting on the trackbed”), Mr Stone erred by finding that the skilled person would not assess permeability in light of the pressure applied by the track, sleeper and ballast. Instead, Fiberweb submitted (citing the patent’s reference to a specific embodiment) that the claim required the liner to be impermeable at 2.9kN/m2 (equivalent to the pressure exerted by the load of the track, sleeper and ballast).
Delivering the reasoned judgment of the Court of Appeal, Arnold LJ noted that although unusual, the relevant integer of the claim included a definition of “normally impermeable” and “on the face of it, therefore, there would appear to be little room for argument as to the meaning of the integer”. He rejected Fiberweb’s argument, finding that:
- The reference to 2.9 kN/m2 in the specification did not correspond to how “normally impermeable” was defined, noting that it is rarely appropriate to read limitations into definitions from stray comments in the specification; and
- Fiberweb’s argument confused the effect of static load on the filtration layer (caused by the load of the track, sleeper and ballast) and dynamic load (exerted during the passage of a train). He noted that in accordance with basic physics (Newton’s third law), once constructed the system is in equilibrium and although the weight of the track, sleeper and ballast resulted in liner compression, this had no bearing on the hydrostatic pressure of any water present.
Fiberweb’s argument in respect of novelty over Hoare was based on a cross-reference to GB 1 355 373 (Gore) (which parties did not dispute formed part of the Hoare disclosure). Gore, in the context of sixteen example materials, disclosed a material useful for filtration which was said to be impermeable at 35kPA and permeable above 70kPA. Upholding the decision of Mr Stone, Arnold LJ emphasised the need to understand the purpose for which Hoare cross-referred to Gore. He noted that Hoare did not refer to any of the examples in Gore or direct the reader to use any of the materials disclosed in such examples. On this basis, the Court of Appeal held that Hoare did not anticipate the claims and refused the appeal.
Although offering little comfort to Fiberweb and making no impact on the ultimate decision, Arnold LJ accepted Fiberweb’s argument that Mr Stone erred by concluding in his novelty analysis that “the invention described in Hoare, even including the reference to Gore, does not read onto the structure described in the Patent” as “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”. Arnold LJ agreed that this analysis amounted to a conclusion that Hoare did not disclose the inventive concept of the Patent, which may be relevant in the context of inventive step but is not relevant to novelty.