Conoco v. EEI (Fed. Cir. 2006).
Conoco’s asserted claims were directed to drag reducing agents for gas pipelines. EEI lost a bench trial and appealed on claim construction. One claim in particular included the transition “consisting of” rather than the more open-ended “comprising.”
First, the CAFC refused to review the construction de novo because it had not been properly objected to at trial. Reviewing for clear error (substantial evidence) the appellate panel easily found that certain impurities found in the accused product did not allow EEI to escape infringement even though the closed “consisting of” language was used.
[I]mpurities that a person of ordinary skill in the relevant art would ordinarily associate with a component on the "consisting of" list do not exclude the accused product or process from infringement.