The Court of Appeals for the Federal Circuit (the patent appeals court) has re-invigorated the claim element vitiation theory by stating that a claim element or limitation is vitiated when there is no equivalent to the claim element in the accused device based upon the well-established function – way – result or insubstantial differences tests for determining infringement under the doctrine of equivalents (DOE). Akzo Nobel Coatings, Inc v Dow Chemical Co., case no. 2015-1331 (Fed. Cir. Jan. 29, 2016 (Available Here).
The patent related to an extrusion process that generated low viscosity aqueous polymer dispersions. To achieve uniform dispersion and distribution, the patent specification stated that the mixture cannot be heated above the boiling point of the carrier liquid or else the liquid boils and it becomes impossible to disperse the polymer.
The two patent claims under consideration recited a claim element or claim limitation which required maintaining the pressure above atmospheric for the extruder at the outlet with a pressurized collection vessel. Claim 2 required that the process be carried out at a temperature of from about 5 to 150°C above the melting point of the polymer.
Dow, the accused infringer, had a process wherein the polymer dispersion exiting the extruder, passed through a valve and then traveled through a series of pipes and heat exchangers and then passed through a filter which collects the material in an unpressurized compartment.
After the U.S. District Court issued a claim construction order, the accused infringer requested early summary judgment of noninfringement. The District Court granted that summary judgment motion.
The District Court construed several disputed claim limitations including “pressurized collection vessel” as — tubing, piping or other container where a desired material accumulates, which is maintained above atmospheric pressure –, and the word “collection” which was construed as — some of amount of material must be permitted to accumulate within the vessel rather than all of the material flowing through the vessel at a constant rate. — The District Court looked to examples 2 and 3 in the patent specification which stated that the dispersion was collected in a watercooled pressurized vessel maintained at a certain pressure and from which the polymer dispersion, once cooled to below 100°C, could be periodically removed.
The District Court granted summary judgment of noninfringement because the accused infringer’s process did not use a pressurized collection vessel. The District Court also found that the lack of accumulation in the accused device precluded a finding of infringement under the doctrine of equivalents and ruled that, for the patentee to prevail on infringement by the doctrine of equivalents, such a ruling would vitiate the claim language that the “pressurized collection vessel” be a “container where the desired material accumulates.”
The District Court rejected the patentee’s argument that pressurized collection vessel and the term “accumulation” should be assigned its ordinary meaning of “gather or receive.”
The Patent Appeals Court referenced the Phillips case, the Markman case and the Vitronics case and stated that claim construction begins with the language of the claim itself as it would have been understood by one of ordinary skill in the art at the time of the invention. The claims must be read in view of the specification which is a part of the patent. The patent specification is always highly relevant to the claim construction analysis and usually it is dispositive, it is the single best guide to the meaning of a disputed claim term. Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 (Fed. Cir. 2005); Markman v Westview Instruments Inc., 52 F.3d 967, 979 (Fed. Cir. 1995); and Vitronics Corp. v. Conceptronic Inc., 90 F.3d 1576, 1582 (Fec. cir. 1996).
By allowing the “collection” to mean “receive” would render the term “collection” entirely superfluous and allow any pressurized vessel to constitute a “pressurized collection vessel” and such a result is disfavored by the courts. Stated otherwise, the claim limitation – collection – would be vitiated from the claimed invention.
An important practice note is that the terms “collection” and “collected” were only used twice in the patent specification. Important claim terms should be explained thoroughly in the patent specification.
Regarding the doctrine of equivalents (DOE), the classic tests are the function – way – result inquiry and insubstantial differences. A patentee must establish equivalency on claim limitation – by – limitation basis by particularized testimony and linking argument as to the insubstantial differences between the claimed invention in the accused device or process. The function – way – result test often suffices to show the substantiality of the differences. All claim limitations are not entitled to equal scope of equivalents and ultimately many limitations warrant little, if any, range of equivalents.
As the Supreme Court stated, if a theory of equivalents would entirely vitiate a particular claim element, partial or complete judgment should be rendered by the court. Warner-Jenkinson, 520 U.S. at 39, n. 8. As the court explained in earlier cases, saying that a claim element would be vitiated is akin to saying that there is no equivalent to the claim element in the accused device based on the well-established function – way – result test or the insubstantial differences test.
In the present case, to state the position differently, it is the “accumulation” of dispersion in the collection vessel that generates the back pressure. The accused infringer’s process on the other hand uses a valve and does not allow for “accumulation” in the downstream pipes.
As a practice note, the patentee’s expert failed to articulate which construction of “collecting” he referred to in his expert declaration and did not articulate how the differences between the two processes are insubstantial.