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Archived updates for Monday, October 04, 2004

CAFC Holds Festo Presumption Rebutted

In Insituform Technologies Inc. v. Cat Contracting (October 4, 2004) the Federal Cicuit held for the first time that that plaintiffs rebutted the Festo presumption that a narrowing amendment made for a reason of patentability surrenders the entire territory between the original claim limitation and the amended claim limitation. The prosecution history established that "the rationale underlying" the amendment narrowing the scope of literal claim coverage from multiple cups to a single cup bears "no more than a tangential relation to the equivalent in question." Therefore, application of the doctrine of equivalents in this case was not barred.

The only claim at issue related to a process for impregnating a flexible tube liner with resin (above, left) prior to insertion of the liner, inside-out, into a damaged pipe (right).

The liner (above) has an impermeable film on the outside and a resin-absorbent, felt layer on the inside. During the impregnation process, a vacuum is applied to the inside of the liner by cutting a window into the outer, impermeable film, applying a cup (a "vacuum cup") to the outside of the window, and connecting the other end of the cup to a vacuum source. Using the created vacuum, a section of the inside of the liner is impregnated with resin, which is drawn through the liner. The vacuum cup is then moved to another section of the liner while the previously used window is sealed. This process for impregnating the liner with resin allows for impregnation at the jobsite, eliminating the need to transport a heavier, already impregnated liner to the site.

The originally-filed claim covered a process using single or multiple cups at any location downstream of the resin front. The claim was rejected over Everson, which discloses both the use of a continuous vacuum and the creation of that vacuum from only a single vacuum source at the far end of the tube opposite the resin source.

The rejection was overcome by amending claim 1 to include, in a different form, the limitations of original dependent claims 2-4. Dependent claim 2 referred to the vacuum being applied to the interior of the tube, "downstream of the resin mass," while dependent claim 3 stated that the resin is squeezed "in a direction towards the region of the application of the vacuum." It was only in dependent claim 4 that the inventor recited application of the vacuum through a window in the wall of the tube by means of a cup applied to the window, as well as repositioning of the cup.

Insituform had stated to the examiner that Everson?s method was ineffective when dealing with a long length of tube because it required an exceedingly large suction compressor. The court pointed out that Insituform solved this problem by placing the suction source closer to the resin front, thus allowing the use of a smaller suction compressor.

Based on an examination of the prosecution history, the Federal Circuit concluded that Insituform was not estopped from asserting that Inliner?s multiple cup "continuous" process infringed the claim under the doctrine of equivalents.

In particular, the court noted that Insituform made it clear that the difference between its process and Everson was that its process did not have the disadvantage of the Everson process of a large compressor at the end of the liner. There was no indication in the prosecution history of any relationship between the narrowing amendment and a multiple cup process, which is the alleged equivalent in this case. Thus, the court held that plaintiffs successfully rebutted the Festo presumption by establishing that the amendment narrowing the claimed invention from multiple cups to a single cup was tangential to accused process, which used multiple cups attached at different points along the liner tube.
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