Scottish Court of Session considers whether patent can be interpreted without expert evidence

Author: Susan Snedden (IP & Technology Department, Maclay Murray & Spens LLP); Susan Snedden acted for the defender in this case.

Total Containment Engineering Limited v Total Waste Management Alliance Limited [2013] CSOH 135, Court of Session, Scotland, 13 August 2013

Journal of Intellectual Property Law & Practice (2014) doi: 10.1093/jiplp/jpu104, first published online: June 17, 2014

The court decided that, in certain cases, it may be able to rule on questions of patent interpretation without first hearing expert witnesses, but not in this case. The pursuer's pleadings set out a relevant case of patent infringement and the case could proceed to a proof (trial).

Legal context

The Court of Session has jurisdiction over disputes relating to EP (UK) and UK patents.

In Scottish proceedings, preliminary pleas are considered at debate, which takes place prior to a proof (ie trial). One such plea is that the pursuer's pleadings do not set out a relevant case. The basis of the relevancy plea is that, even if everything in the pursuer's written case is true, it does not entitle him to the remedy sought. The onus of proof is on the party raising the plea.

The court must assess the pursuer's pleadings against the substantive law, to determine whether a legally relevant case is set out in the pleadings.

In this case, the defender argued that the pursuer had failed to set out a legally relevant case of patent infringement. In order to accept that the case was irrelevant, the judge would have to decide how two of the patent integers should be interpreted.


Total Containment Engineering Limited (the pursuer) brought a patent infringement against Total Waste Management Alliance Limited, a Scottish company (the defender).

The patent in suit was EP (UK) 1 144 869 B1, relating to technology for handling and transferring oil well drill cuttings. Claim 1 read:
Apparatus for handling drill cuttings in a tank and transferring them therefrom, the apparatus comprising: pump means having a chamber, an inlet opening into said chamber, a rotatable impeller disposed in the chamber and being driven by a motor to draw drill cuttings contained in the tank into the chamber, a discharge outlet on one side of said chamber, and manipulating means operatively associated with the pump means for moving at least the inlet of the pump means vertically, horizontally, and/or laterally within the tank; wherein the manipulating means includes swivel means for orienting the pump means within the tank. It required swivel means for orienting the pump means within the tank, and also required manipulating means for moving the inlet of the pump means within the tank.
The allegedly infringing product was the defender's cuttings storage and transfer unit. This was a storage tank for holding drill cuttings, with a pump flanged to the bottom of the tank in a fixed position. The pump was a dual cylinder positive displacement pump, comprising a hopper, two cylinders, two pistons and a swing tube. Drill cuttings fell from the tank into the pump hopper under force of gravity. The cuttings were drawn into one cylinder, then pushed by a piston from the cylinder into the swing tube and onwards out of the pump. The swing tube moved between the two cylinders so there was a constant flow of drill cuttings into the cylinders and, from there, into the swing tube.


The defender's position was that to succeed, the pursuer would need to prove that the inlet to the pump means moved within the tank, and also that the pump means could be oriented within the tank.

An ordinary interpretation of the word ‘inlet’ indicated that it was the point at which drill cuttings first entered the pump. Based on the pursuer's pleadings about what constituted the tank and the pump, the inlet had to be the point at which the tank and hopper connected. The pursuer admitted that the hopper was bolted onto to the tank and could not move.

Similarly, the pump means were located below the tank in a fixed position and could not be oriented within the tank. At best, only the swing tube could be oriented, not the entire pump means.

The defender argued that the pursuer did not plead that ‘inlet’ or ‘orienting the pump means within the tank’ were technical terms with a special meaning which would be known to the person skilled in the art (PSA). Nor did they plead any relevant background information or common general knowledge that would affect the PSA's interpretation of these integers. As such, these terms should be given their ordinary meaning and the case should be held to be irrelevant.

In response, the pursuer argued that ‘inlet’ could refer to the admission of drill cuttings into any part of the chamber of the pump. It did not have to be the point at which drill cuttings first entered the chamber. Similarly, it was sufficient if part of the pump means could be oriented within the tank. The swing tube could be so oriented. On that basis, the movement of the defender's swing tube and its inlet satisfied these integers.

The pursuer advised that it had expert evidence to support its position on interpretation and argued that it would be inappropriate for the court to conclude that the case was irrelevant without first hearing this evidence.

The court agreed with the pursuer that its pleaded case was not irrelevant. Lord Malcolm quoted from Lord Hoffmann, at paragraph 32 of Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9 (HL), in holding that the meaning of the words used in a patent was:
… highly sensitive to the context of, and background to, the particular utterance. It depends not only upon the words the author has chosen, but also upon the identity of the audience he is taken to have been addressing and the knowledge and assumptions which one attributes to that audience.
Lord Malcolm observed that this approach to interpretation meant that the court should be cautious about accepting any contested invitation to reach conclusions about the interpretation of patent integers without first hearing evidence.

He continued at paragraph 18:
It is well understood that any witness, expert or otherwise, should be aware of, and should not attempt to supplant the proper jurisdiction of the court. However, it is another thing to say that the court need not hear from such witnesses. In their absence, how can the court put itself into the position of the notional addressee?
He also noted at paragraph 20:
There may be cases where the ordinary meaning of the words used in a patent is so straightforward and clear that the precise basis for a contrary interpretation must be narrated in detail on record before an inquiry can be contemplated; but in my view, this is not such a case. The pursuer sets out its construction of the claims, and contends that before resolving the issues, the court should allow itself to be educated as to relevant technology and processes. Mr Clark submits that, thereafter, the proposition that the lower end of the swing tube is the ‘inlet’ of the pump, and that it includes ‘manipulating’ or ‘swivelling’ characteristics within the meaning of the claims, will be easier to understand. I cannot gainsay that.
Thus, he concluded, the case was legally relevant, adding that the provision of witness statements and expert reports would ensure the defender had fair notice of the pursuer's case in advance of the trial.

Practical significance

To understand the practical significance of this case, it is instructive to note what happened after the debate. Lord Malcolm ordered the pursuer to provide its relevant expert evidence in advance of the usual exchange of expert reports and witness statements between the parties. Thus the defender was able to see the pursuer's evidence on infringement and interpretation before finalizing its own expert evidence.

A number of significant points can be taken from this decision and its aftermath. First, the Scottish courts are likely to adopt a cautious approach to reaching a view on questions of interpretation in the absence of any expert evidence. That said, the court acknowledged that there may be some cases in which it could do so. It thus remains possible that an infringement action could be dismissed at debate, without the need for a full trial on the issues.

Secondly, the order issued by the judge subsequent to the debate highlights that whilst parties may not be required to include full details of their position on interpretation in the pleadings, taking this approach is risky. If they fail to do so, they may be ordained to provide their expert evidence in full before the other party provides its expert evidence. This can hand a tactical advantage to the other side which will then benefit from obtaining full notice of the opposing party's expert evidence prior to the finalization of their own evidence.

Finally, the Scottish IP court rules were amended in 2012 to provide the IP judges with complete discretion to make any orders they wish in IP cases. In addition, every case is now heard by the same judge from beginning to end. As a result, the judges have a more in-depth knowledge of the cases, which allows them to tailor the procedure to each case. These changes have greatly improved the speed and efficiency of litigating IP disputes in the Scottish courts.

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