Warminster Fiberglass Company, Inc. v. Delta Fiberglass Structures, Inc., AKA Delta Reinforced Plastic Structures, Inc., Defendant/cross-Appellant

Citations: 22 F.3d 1104; 1994 U.S. App. LEXIS 17926Docket: 93-1047

Court: Court of Appeals for the Federal Circuit; March 16, 1994; Federal Appellate Court

Combined Opinion SummaryCombined Opinion Original

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Federal Circuit Local Rule 47.6(b) indicates that opinions and orders not designated as citable precedent cannot be used as precedent, although issues like claim preclusion and judicial estoppel may still arise from them. In the case of Warminster Fiberglass Co., Inc. v. Delta Fiberglass Structures, Inc., Warminster appeals a district court ruling that Delta did not infringe claims 1, 2, 4, 6, or 11 of U.S. Patent No. 4,391,704 related to gas-extraction apparatus for wastewater treatment. Delta cross-appeals the ruling that the patent is not invalid. The court vacates the judgment and remands for further proceedings.

The patent's sole independent claim details a wastewater treatment settling tank apparatus designed to prevent the escape of noxious gases. The district court interpreted the terms 'integral' and 'side wall' to necessitate a one-piece construction for the hood. It found that Delta's hoods have a gap between the trough cover and scum baffle, indicating they are two separate pieces, which led to the conclusion of no literal infringement. Additionally, the term 'confined region' was construed to require a completely sealed hood. The presence of the gap in Delta's hoods meant they did not create a confined region, further supporting the finding of no literal infringement. The court also ruled against infringement under the doctrine of equivalents, stating that Delta's apparatus is fundamentally different from the claimed apparatus, as it transports gases rather than sealing and neutralizing them.

The district court determined that the accused device could capture gases from a scum skimmer during its operation, while the claimed device could not. The court also ruled that the patent was valid without further explanation. Warminster appealed the noninfringement judgment, arguing that the term "confined region" was misinterpreted. Warminster contends that a "confined region" does not need to be entirely sealed and defines it as a localized enclosure that allows gas collection from the weir area, with the degree of confinement varying by the gas treatment method used. 

To assess infringement, the court must interpret the patent claims and compare them to the accused device. Claim construction considers the patent language, prosecution history, and external evidence such as expert testimony and dictionaries, with de novo review by the appellate court. The ultimate noninfringement finding is fact-based and reviewed for clear error. 

Claim 1 of the '704 patent specifies a hood that creates a "confined region" to capture noxious gases from wastewater, with mechanisms for treating those gases to prevent atmospheric discharge. The patent describes a hood with an air port and a suction pump for gas removal, indicating that it cannot be entirely sealed. Alternative methods mentioned include using a chemical oxidant or gas-absorbing material within a sealed hood. Therefore, "confined region" does not necessitate complete sealing; instead, the extent of confinement is determined by the gas treatment approach. Delta argued that "confined" should mean completely sealed based on the inventor’s deposition stating that barriers could be impervious to gas flow. However, this testimony cannot override the patent's explicit disclosures.

In Senmed, Inc. v. Richard-Allan Medical Indus. Inc., the court found that the district court incorrectly interpreted the term 'confined region' in the patent claims as requiring a 'completely sealed' environment, which was inconsistent with the patent document's description. The Delta apparatus effectively captures noxious gases in a defined confined area, contradicting the lower court's conclusion that it lacked a 'confined region.' Warminster argued that the terms 'integral' and 'side wall' were misinterpreted to necessitate a 'one-piece' construction. The court agreed, stating that claim 1 does not limit the hood and scum baffle to a single-piece design unless explicitly stated in the patent or its history. Warminster's definition of an 'integral' scum baffle as part of the hood assembly aligns with the patent specifications that discuss the hood being made in sections, thus not requiring it to be one-piece. Delta's argument referencing the prosecution history was found insufficient to necessitate a one-piece requirement for the scum baffle and hood. Furthermore, statements from Warminster's representatives about their products did not pertain to the claims of the '704 patent, which clearly allows for the hood to be molded in sections, supporting a broader interpretation of 'integral' that includes various constructions beyond a single piece.

Warminster's characterization of its one-piece commercial products as 'patented' does not restrict the definition of 'integral' in claim 1. The district court wrongly concluded that claim 1 necessitates a one-piece construction for the hood and sidewall scum baffle. Evidence, including the patent documentation, illustrates that the invention does not require separate baffle plates, as the hood integrates a baffle within its structure. The district court correctly identified Delta's hood and scum baffle as 'two-piece' and 'separate and distinct,' affirming that the integral and sidewall requirements of claim 1 are absent in Delta's products. Warminster contends the court also erred in rejecting infringement under the doctrine of equivalents, which allows for infringement even if the accused device does not literally match the claim, provided it performs the same function in a similar manner to achieve a comparable result. Warminster argues that Delta's apparatus effectively prevents gas emissions from wastewater treatment, similar to the claimed invention, despite the presence of a gap between components. The district court's finding of substantial differences in operation between Delta's and the claimed hood was based on a mistaken interpretation of the claim, as the claim is not confined to a sealed hood. Therefore, the court's conclusions regarding equivalence must be reconsidered. The ruling of no infringement under the doctrine of equivalents is vacated, and the case is remanded for further analysis based on the corrected claim interpretation. Additionally, Delta's cross-appeal asserts that the district court erred in concluding the patent's validity, citing prior art references that allegedly anticipate or render the claims of the '704 patent obvious.

The district court's judgment regarding the validity of the patent is vacated due to a lack of findings and the vacatur of the infringement issue. Consequently, the case is remanded for necessary fact findings and legal conclusions as per Fed. R. Civ. P. 52(a). The court also vacates the judgment concerning noninfringement under the doctrine of equivalents. Delta's argument that any disagreement about patent claim language creates a question of fact requiring clear error review is rejected, referencing Johnston v. IVAC Corp. The asserted claims 6 and 11 pertain to the unsealed hood apparatus, while claims 7-10, concerning the sealed hood apparatus, have not been asserted by Warminster. The inventor's testimony regarding the term 'confined region' is deemed not limiting, and statements from Warminster's current and former presidents are similarly not authoritative. Delta's assertion that its covers confine gases through an air gap is dismissed as implausible. The court does not address Warminster's hearsay objection to the inventor's statement since it is not controlling. Additionally, Delta's claim that some accused devices lack the 'treating means' of claim 1, which affects the literal infringement, remains unresolved and is left for the remand. No costs are awarded.