Clearvalue v. Pearl River: Ranges Within Ranges - When Are They Patentably Distinct?

The February 17 decision in ClearValue Inc. v. Pearl River Polymers Inc., __ F.3d __ (Fed. Cir. 2012), is the latest effort of the U.S. Court of Appeals for the Federal Circuit to show how to determine when a narrow range claimed in a patent is anticipated and thereby rendered invalid because of a broader range that has been disclosed in the prior art. The patent in dispute, owned by ClearValue, claims a process for clarifying water where the water to be treated has alkalinity of not more than 50 ppm. The case is equally applicable to patents claiming other kinds of composition and processing ranges for chemical or biological inventions. There was only one claim at issue on appeal to the Federal Circuit in ClearValue. It reads as follows:

A process for clarification of water of raw alkalinity less than or equal to 50 ppm by chemical treatment, said process comprising: adding to the water and, prior to or after adding to the water, blending at least one aluminum polymer with a high molecular weight quaternized ammonium polymer in an amount sufficient to form a flocculated suspension in the water and to remove turbidity from the water, said high molecular weight quaternized ammonium polymer comprising at least an effective amount of high molecular weight di-allyl di-methyl ammonium chloride (DADMAC) having a molecular weight of at least approximately 1,000,000 to approximately 3,000,000 and said aluminum polymer including at least an effective amount of poly-aluminum hydroxychloride [ACH] of a basicity equal to or greater than 50%. (Emphasis added.) The prior art showed a similar process but with a different alkalinity range. U.S. Patent 4,800,039 issued to Hassick taught that a combination of high molecular weight DADMAC polymer with ACH "synergistically reduces turbidity in aqueous solutions, particularly low-turbidity... low alkalinity systems (i.e., 150 ppm or less)" (emphasis added). ClearValue's expert observed at trial that Hassick taught that the process described in Hassick's patent "does not work well." The expert saw this as a teaching away from the use of ClearValue's claimed invention, and he therefore testified that one of ordinary skill in the art would not have found use of the claimed invention obvious to clarify water using ACH with high molecular weight DADMAC. At the District Court level, the jury found the expert's testimony to be sufficient to show that ClearValue's patent was both novel and unobvious over Hassick. The...