Hewlett Packard GmbH & Anor v Waters Corporation & Anor

Patent claims are construed in their specification and technical context, but courts should not add a continuous-adjustment limitation where the claim does not require one. Step-wise adjustment can fall within a claim requiring stroke volume to respond to desired flow rate. For novelty, prior art must disclose the claimed subject matter directly and unambiguously, or its directions must inevitably produce it. A merely possible implementation is insufficient. Obviousness requires an assessment of the difference from the prior art and evidence that the claimed solution would have been obvious. A different technical idea and no evidential basis for departing from the prior art may defeat an obviousness challenge.

Hewlett-Packard GmbH and Agilent Technologies Deutschland GmbH owned EP (UK) 0309596, concerning a high-pressure pumping apparatus for liquid chromatography. Pumfrey J held the patent valid but found no infringement.

The patentees appealed against non-infringement. Waters Corporation and Waters Limited cross-appealed on novelty and obviousness. The central issues were the construction of claim 1, whether step-wise changes in stroke volume were covered, and whether Saito disclosed or made obvious the claimed pulsation-reduction feature.

Lord Justice Aldous delivered the leading judgment. Lord Justices Tuckey and Rix agreed, making the decision unanimous.

1. Construction and infringement. Section 125 of the Patent Act 1977, together with the Protocol on Interpretation of Article 69 of the EPC, required a construction between strict literalism and treating the claims merely as guidelines. The result had to combine fair protection for the patentee with reasonable certainty for third parties. The court applied the approach explained in Wheatley v Drillsafe [2001] RPC 133.
2. The characterising part of claim 1 required control means coupled to both pistons for adjustment, but did not require both pistons to be adjusted at every flow-rate increment. Nor did it require continuous variation of stroke volume. Both Waters pistons had their stroke volumes adjusted when the operating range changed, so the claim covered the step-wise operation and Waters infringed.
3. Novelty. Applying the strict test in General Tire & Rubber Co. Ltd v Firestone Tyre & Rubber Co. Ltd [1972] RPC 457, prior art had to disclose the claimed subject matter directly and unambiguously, or its directions had to inevitably produce it. Saito disclosed a two-stage pump and step-wise cam ranges, but its global feedback mechanism addressed detected pressure variations and did not clearly disclose the final claim feature of reducing output pulsations in response to desired flow rate. Waters had not shown that the feature was inevitable. Saito therefore did not anticipate the patent.
4. Obviousness. The structured approach in Windsurfing International v Tabur Marine (Great Britain) Ltd [1985] RP 59 was appropriate. The only relevant difference was the final pulsation-reduction feature. There was no evidence or reason why a skilled person would depart from Saito's global feedback teaching to reach the claimed invention. The claim was not obvious.
5. The patentees' appeal was allowed and Waters' cross-appeal was dismissed. Waters were ordered to pay the relevant costs; permission to appeal to the House of Lords was refused, subject to consequential directions in the order.

1. Court of Appeal (Civil Division): Allowed the patentees' appeal and dismissed Waters' cross-appeal.
2. Chancery Division: Pumfrey J held EP (UK) 0309596 valid but not infringed in his judgment of 24 April 2001.