## Facts

- National Recovery Technologies, Inc. (NRT) owned U.S. Patent No. 5,260,576, directed to automated recycling equipment for sorting plastic containers, especially separating PVC from PET using penetrating electromagnetic radiation.
- Prior sorting systems measured radiation transmittance/absorption, but mangled or irregular containers created thickness variation that could cause PET to resemble PVC in measured transmittance.
- Claim 1 recited irradiating multiple items, detecting transmitted radiation to generate “process signals,” and “selecting for processing” only those signals that did not pass through irregularities in the items.
- NRT sued Magnetic Separation Systems, Inc. (MSS) and an individual defendant for infringement in the Middle District of Tennessee.
- MSS sought summary judgment that claim 1 (and dependent claims 2–8 and 10) were invalid for lack of enablement under 35 U.S.C. § 112 ¶ 1, contending the specification did not teach how to perform the “selecting” step without undue experimentation.
- Inventor testimony indicated that, as of the filing date, additional research and experimentation were needed to determine how to implement the signal-selection requirement.

## Issues

1. Whether claim 1 of the ’576 patent was invalid for lack of enablement because the specification failed to teach how to “select[] for processing” signals that did not pass through irregularities without undue experimentation.
2. Whether dependent claims 2–8 and 10 were likewise invalid because they incorporated the same non-enabled limitation.

## Decision

- The Federal Circuit affirmed summary judgment of invalidity for lack of enablement.
- The court held that claim 1 was not enabled because the specification did not provide sufficient teaching for the critical “selecting” limitation.
- The court held dependent claims 2–8 and 10 invalid because they depended on the same non-enabled feature.

## Legal Principles

- Under 35 U.S.C. § 112 ¶ 1, a patent must teach a person of ordinary skill in the art to make and use the full scope of the claimed invention without undue experimentation, assessed as of the filing date.
- A claim that relies on a core functional limitation may be non-enabled when the specification states the desired result but does not disclose concrete means (e.g., procedures, algorithms, or apparatus) to achieve it.
- Broad functional claim scope must be supported by disclosure commensurate with that breadth; a gap between expansive functional language and minimal implementation detail can defeat enablement.
- Evidence that the inventors themselves required substantial post-filing research to perform a claimed step supports a finding of undue experimentation and lack of enablement.
- When a dependent claim incorporates a non-enabled limitation from an invalid independent claim, the dependent claim is invalid absent an independent enabling basis.

## Conclusion

The Federal Circuit held the asserted claims invalid because the patent’s key functional requirement—selecting process signals that did not pass through irregularities—was not taught with sufficient implementation detail to allow practice of the full claim scope without undue experimentation, and the dependent claims fell with the non-enabled independent claim.


Nat'l Recovery Techs., Inc. v. Magnetic Separation Sys., Inc., 166 F.3d 1190 (Fed. Cir. 1999)