by Robert Ambrogi - Editor
BullsEye Newsletter: July 2006
Expert
testimony involving the science of computational fluid dynamics
(CFD) is admissible to prove patent infringement, the U.S.
Court of Appeals for the Federal Circuit decided June 1.
The court deep-sixed the defendants' objections to the testimony, finding that
its concerns went to the testimony's weight, not its admissibility.
The CFD testimony came in a case involving "slurry tanks"
– tanks used to store and process chemicals and organic waste
products for later reuse. A maker of one such tank, Liquid Dynamics
Corp. (LDC), alleged that rival Vaughan Company Inc. infringed
its patented system.
A jury found in LDC's favor and further determined that the infringement was
willful. It awarded LDC damages of $1.1 million. Based on the jury's willfulness
finding, the district court trebled the award. The court also awarded LDC attorneys'
fees of $1.5 million.
Vaughan appealed on several grounds, including the admissibility of computer
simulations and expert testimony using CFD.
The patent at issue involved a system of pumps that stir mixtures of solids and
liquids in large, million-gallon tanks. Its primary use is in mixing wastewater
and manure. The patent involved a storage tank equipped with submerged agitators
capable of generating a flow of liquid throughout the tank.
Simulations Questioned
To prove its case, LDC had to show that the flow of liquid in Vaughan's allegedly
infringing tanks matched helical and rotational patterns claimed in the patent.
Its expert witness, Richard M. Lueptow, a Mechanical Engineering Professor at
Northwestern University, presented computer simulations showing these flows.
In its appeal to the Federal Circuit, Vaughan challenged Lueptow's testimony
on two grounds, first arguing that the parameters used to run the simulations
were inaccurate and then contending that the simulations did not show the required
rotations.
The court characterized Vaughan's challenges as being to "the admissibility
and reliability of Lueptow's expert scientific analysis and opinion." However,
citing Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 589 (1993),
the court said that Vaughan’s argument was actually directed not to the
reliability of CFD analysis in general, but to the parameters the expert applied
in performing the analysis.
"Indeed," the court noted, "CFD analysis has been previously recognized
in the scientific community and has been recognized as reliable by at least one
circuit."
This meant, the court continued, that Vaughan’s challenge went to the weight
of the evidence rather than to the admissibility of the expert's testimony and
analysis under Daubert.
"Though he admitted that his models did not exactly match the various accused
tanks, this fact was fully discussed on cross examination,"
the court said. "[H]is models were not the perfect models
of each individual tank, but they were based on reliable scientific
methodology and subject to cross examination and the proffering
of further scientific analysis by Vaughan."
A reasonable juror could weigh this testimony in LDC's favor, the court concluded. "Therefore,
we will not contravene the province of the jury by reweighing Lueptow’s
testimony."
As to Vaughan's second challenge – that the simulations did not show the
required rotations – the court again found in LDC's favor.
Vaughan argued that the simulations did not incorporate a sufficient number of
iterations to replicate the tank's actual operation. But the court said that
this argument did not discount the expert's testimony, which he based not only
on his own simulations, but also on ones performed by others, including Vaughan.
"[S]ufficient evidence still existed for a reasonable juror to find infringement," the
court reasoned.
In light of these determinations, the circuit court affirmed the decision of
the district court.
The case is Liquid Dynamics Corp. v. Vaughan Company Inc., Case Numbers
05-1105, 05-1325, 05-1366, 05-1399 (Fed. Cir. June 1, 2006).
Click
here for full text of this opinion.
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