Court questions expert's credibility in patent infringement finding

June 9, 2010

Weatherford Canada Ltd. et al. v. Corlac Inc. et al., 2010 FC 602

Justice Phelan of the Federal Court of Canada released a 119-page judgment in respect of Canadian Patent No. 2,095,937 (the “’937 Patent”) relating to a seal assembly combination designed to fix the problem of leaking stuffing boxes on rotary progressive cavity pumps – a problem that has troubled all the heavy oil producers since the early 1980’s.

The plaintiffs alleged that the defendants had been directly infringing the ‘937 Patent since at least 1999 as a result of manufacturing and selling drive systems for rotary oil well pumps that included the patented assembly for restraining oil leakage.  They also alleged the Defendants had induced and procured others including their customers to infringe the '937 Patent.

The defendants basic defence was that the named inventor of the ‘937 Patent was not the true inventor, and that the plaintiffs therefore had no valid rights under the ‘937 Patent.  The defendants further denied infringement and attacked validity of the ‘937 Patent.  In addition, the defendants argued that they were the true owners of the ‘937 Patent by assignment/licence and that it was the plaintiffs who had in fact infringed their patent rights.

The plaintiffs were largely successful on the issues and judgment was granted accordingly.  As to infringement, Justice Phelan found that the absence of direct evidence from one or more employees of the defendants was startling. There was no corporate evidence as to the development of the defendants’ devices, the knowledge of competing devices, efforts to create a differentiated product or anything else to suggest that there was no intended infringement.  In fact, a former head engineer of one of the plaintiffs, which designed rotating stuffing boxes, left his employment (shortly before the owner of the ‘937 Patent licensed his employer) to join one of the defendant companies, which subsequently began the manufacture and sale of infringing product.  The timing of the change of jobs, the nature of the competitive market for this product then and later and the timing and similarity of the defendants’ products called out for an explanation. Absent an explanation and given the plaintiffs’ evidence of infringement, the Court drew an adverse inference and came to the conclusion that the defendant intentionally set out to create a product which they knew or ought to have known would infringe the '937 Patent.

It is interesting to note that much of the outcome of this case turned on the fact that the evidence from the plaintiffs’ experts was overwhelmingly preferred to that offered by the defendants’ experts.  In fact, the defendant’s key expert was found to lack credibility.  Dicta from Justice Phelan provides a useful lesson on how experts are expected to conduct themselves in Court:

“[52] Muller’s testimony did not stand up under cross-examination and he was shown to be evasive, aggressive, arrogant and unhelpful. Mr. Muller’s evidence was significantly undermined by his failure to directly answer questions which admitted of only a direct answer, and by his disrespect and arrogance towards opposing counsel and his longwinded diatribes in giving unresponsive answers.

[53] The Court must conclude that his evidence was of little specific assistance and particularly where it conflicted with that of the Plaintiffs and in particular Dr. Salant, the Court accepts the Plaintiffs’ evidence. While no doubt sincere in trying to assist his client, Mr. Muller was apparently unaware of the obligations that an expert owes to the Court and the assistance which an expert is to render in aiding the Court’s understanding.”

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