## Facts

- Peter Gabor Kalman owned U.S. Patent No. 3,471,017 covering a process and apparatus for filtering heat-softened material (e.g., thermoplastics) in an extrusion line using a movable filter ribbon.
- The apparatus places the filter ribbon across a flow passage and uses entry/exit sealing ports with heaters and water-cooling channels to maintain cooler zones near the ports.
- Material in the ports forms rigid or semi-rigid “self-replacing” sealing plugs around the ribbon, maintaining a pressurized seal while permitting ribbon movement.
- The filter ribbon can be advanced intermittently (by changing port temperatures to soften plugs and allow movement) or continuously (by maintaining intermediate temperatures to permit slow forwarding).
- Kimberly-Clark used plastic extrusion filtering devices that Kalman alleged practiced the patented process and apparatus.
- Kimberly-Clark argued the claims were invalid as anticipated by an earlier patent (Moziek), asserting it disclosed the same invention.
- After a bench trial, the district court held claims 1, 3, 15, 18, 20, 23, and 25 valid and infringed, rejecting the anticipation defense.
- Kimberly-Clark appealed to the Federal Circuit.

## Issues

1. Whether the Moziek patent anticipated the asserted claims under 35 U.S.C. § 102.
2. Whether an allegedly anticipating reference must enable or “teach” the claimed process and operational features to anticipate.
3. Whether the district court clearly erred in finding Kimberly-Clark’s devices infringed the asserted claims.

## Decision

- The Federal Circuit affirmed the district court’s judgment.
- The court upheld the finding that Moziek did not anticipate because it did not disclose and enable the claimed combination of structural features and coordinated operation (including temperature control and sealing-plug behavior that permits ribbon advancement while maintaining a seal).
- The court upheld the finding of infringement, concluding the district court’s determination was not clearly erroneous.
- Because the case followed a bench trial, the Federal Circuit applied clear-error review to underlying factual findings on anticipation and infringement.

## Legal Principles

- Anticipation requires a single prior art reference to disclose every claim element arranged as in the claim.
- A reference cannot anticipate unless it enables a person of ordinary skill in the art to practice the claimed invention without undue experimentation; anticipation and enablement are linked for this purpose.
- For process-and-apparatus claims with operational limitations, anticipation requires disclosure of the operative teaching of the claimed method of operation, not merely a superficially similar arrangement.
- On appeal from a bench trial, factual findings supporting validity and infringement determinations are reviewed for clear error.

## Conclusion

The Federal Circuit left in place a judgment that Kalman’s filtering patent was valid and infringed, holding that the asserted prior art did not anticipate because it failed to teach and enable the claimed temperature-controlled sealing and filter-ribbon advancement that allowed filtration without interrupting extrusion.


Kalman v. Kimberly-Clark Corp., 713 F.2d 760 (Fed. Cir. 1983)