Mira wins patent infringement claim against Triton: a summary
Following Mills & Reeve’s successful representation of market leading shower manufacturer Kohler Mira (Mira) in its patent infringement claim against Norcros Group (Triton), this article provides a brief background and summary of the claim. The dispute concerned Mira’s dual outlet electric shower technology and Triton’s DuElec range of showers which was held to infringe Mira’s patent GB 2,466, 504 (the Patent).
Mira commenced proceedings in the Intellectual Property Enterprise Court in December 2022 claiming Triton had infringed the Patent. Triton denied infringement and counterclaimed for revocation of the Patent.The trial took place on 8 and 9 July 2024. In a judgment, which was handed down on 16 December 2024, Her Honour Judge Melissa Clarke held Mira’s Patent to be valid and infringed. HHJ Clarke was satisfied that the inventive concept of the Patent was sufficiently inventive to deserve the monopoly protection of the Patent and held that the relevant claims of the Patent (namely 1, 4 and 17) were:
- novel over the prior art
- inventive
- not invalid for lack of sufficiency
and that each of the products of the DuElec range fell within the scope of protection of the claims 1 and 4 of the Patent on the basis of normal construction and so infringe the Patent.
Background
Both mixer and electric showers were well-established products in December 2008 (when the Patent was filed). However, whereas mixer showers were available with a single outlet and a dual outlet (eg, a handheld and an overhead showerhead), electric showers available in the UK market at that time only had one outlet.
Mira’s Patent recognises that in an electric shower the diverter valve must carry functionality over and above diverting water from one outlet to another. If the diverter valve impedes the flow of water, the flow rate would slow down and the water passing through the heater unit would spend longer in contact with the element. A significant reduction in flow rate could lead to an excessively high temperature in the heated water which may scald the user when it is discharged. The Patent identifies this risk and claims “the diverter valve is configured so that the flow rate is substantially unchanged during changeover.”
Inventive concept
Judge Clarke accepted Mira’s position on the inventive concept of the Patent as: “the perception or the appreciation of the problem that having a diverter valve in a dual-outlet electric shower can give rise to a risk of scalding, and overcoming it.”
Validity
Triton challenged the validity of Mira’s Patent on the basis of novelty, obviousness and insufficiency. Triton alleged the Patent was obvious over a piece of prior art called Deeley which contained a cross-reference to a patent called McMaster-Christie.
On novelty, Judge Clarke said: “… Triton is very far from satisfying me that there was a clear and unambiguous prior disclosure of all the features of Claim 1 … or that there was any enabling disclosure…”
On obviousness, Judge Clarke said: “I have no doubt that the steps which were required to get from Deeley alone to the inventive concept would not have been obvious.”
Judge Clarke continued: “Mira took the small and simple step of identifying the problem which I have found was known in the common general knowledge but appreciating that it could be solved by the installation of a diverter valve which leaves the flow rate substantially unchanged during changeover from one outlet to the other. That solution was under the noses of all of those involved in the design of electrics showers, yet they had not solved it.”
On sufficiency, whilst Triton alleged the term “substantially unchanged” did not have a sufficiently clear meaning, the Judge held it capable of determination and adopted Mira’s “risk of scalding criterion”, namely: “when water is flowing at a selected water temperature while the heating elements are energised, any increase in temperature during changeover from one or more selected outlets to another selected one or more outlets does not give rise to a risk of scalding.”
Infringement
Mira claimed infringement of claim 1 and claim 4 of the Patent on both normal construction and equivalence. The dispute centered on claim 1 of the Patent about whether the diverter valve is configured so that the flow rate is substantially unchanged during changeover from one or more selected outlets to another selected one or more outlets
Triton argued that it was wrong of Mira to treat claim 1 as if it were a claim to a complete shower unit when, Triton argued, it was a claim to one component of a shower unit. The Judge accepted Mira’s expert’s opinion that it made no technical sense to analyse the operation of the diverter valve absent the context of the installation.
Triton’s expert accepted that Triton’s DuElec range “seamlessly divert from one outlet to the other” (which is claimed as a feature in Triton’s own marketing material). Adopting Mira’s risk of scalding criterion, the Judge construed the claim as requiring the operation of the diverter valve to achieve changeover between the different outlets so as not to give rise to a risk of scalding. She was satisfied that Triton’s DuElec range fulfils that requirement. Accordingly, the DuElec range of showers fell within claim 1 (and, it follows, claim 4) of the patent on the normal construction and infringe it. It was therefore not necessary to consider infringement by equivalence.
The judgment is subject to appeal.
Kohler Mira was represented by Mills & Reeve LLP, and Douglas Campbell KC and Thomas Lunt of Three New Square IP.
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