PRIMING THE PUMP: A QUESTION OF CONTROL

Rummaging through BAILII this afternoon the IPKat has just unearthed a fresh patent appeal decision, Agilent Technologies Deutschland GmbH v Waters Ltd [2005] EWCA Civ 987, in which the Court of Appeal (Ward, Jacob and Neuberger LJJ) upheld the ruling of trial judge Mr Justice Pumfrey today.

Agilent, who owned a patent for a pump and control system, sued Waters for infringement. The court had previously found that an earlier automatic version of Waters' device infringed the patent, which was valid. Waters then produced a manual version of the device, which was the subject of this action. The pump and control system of the manual device operated in ‘manual mode’, with the flow rate and stroke length being independently selected by the operator. There was no automatic change of range and the manual device no longer maintained any predetermined relationship between stroke length and flow rate other than that imposed by the device's maximum and minimum possible frequencies and stroke lengths. The sole question before Pumfrey J was whether claim 1 of Agilent's patent covered the manual device. He said it did not, so Agilent appealed, maintaining that the characterising portion of claim 1 provided:

‘Control Means (a) coupled to the drive means (b) for adjusting the stroke length of the pistons … (c) in response to the desired flow rate of the liquid delivered … (d) with the stroke volume … being decreased when the flow rate is decreased and vice versa, (e) such that pulsations in the flow of liquid delivered to the output of the pumping apparatus are reduced’,

and that those words covered Waters' manual device as a matter of plain language.

The Court of Appeal upheld Pumfrey J's interpretation of the patent, adding that patent claims should be construed as read by the notional skilled man in context. In claim 1 it was the ‘control means’ and not the operator which was to adjust the stroke length ‘in response to the desired flow rate’. The operator was not part of the control means and the response called for by feature (c) of the claim was not present in Waters' device.

The IPKat concurs with this conclusion. Indeed, he thinks it would have been difficult to reach any other conclusion and wishes that cases like this didn't get appealed quite so often ...

More on pumps here, here and here
Pump jokes here and here (not very funny unless you're into cars)