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Judge Gregory Sleet Issues Markman Order in Fluid Filtering Patent Infringement Case

Chief Judge Sleet recently issued a claim construction order after holding a Markman hearing in the patent infringement case Hollingsworth & Vose Filtration Ltd. v. Delstar Techs., Inc., C.A. No. 10-788-GMS (D. Del. Jul. 10, 2012). In the order, Judge Sleet construed the following terms:

– “comprising . . . a blend of polypropylene fibres and dry spun halogen free acrylic fibres”
– “substantially smooth surfaces”
– “significantly reduced cracks and fissures in the surfaces of the acrylic fibres than if produced by wet spinning”
In construing the first of these claim terms, Judge Sleet found the defendants’ reliance on Dippin’ Dots, Inc. v. Mosey, 476 F.3d 1337 (Fed. Cir. 2007) (write-up at Patently-O) “for the proposition that the term ‘comprising’ does not create an open-ended claim” improper. Id. at 1 n.1. Rather, he noted, the term “comprising” traditionally means “including, but not limited to.” Judge Sleet therefore construed this claim term to mean “a mixture of fibres that includes at least polypropylene fibres and dry spun halogen free acrylic fibres.” Id. at 1 (emphasis added).


Hollingsworth & Vose Filtration Ltd. v. Delstar Techs., Inc., C.A. No. 10-788-GMS (D. Del. Jul. 10,…

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