Appeal No. 2001-1628 Page 7
Application No. 09/054,794
particular findings related thereto. See Dembiczak, 175 F.3d at 999, 50 USPQ2d at
1617. Broad conclusory statements standing alone are not "evidence." Id.
In this case, we find no motivation, suggestion or teaching in the combined
teachings of the applied prior art (Koshoffer, Shekleton and Ekstedt (U.S. Patent No.
3,899,884 incorporated by reference in Koshoffer)) to have modified the gas turbine
engine combustion system of Koshoffer to have arrived at the claimed subject matter.
In that regard, we note that the examiner has not produced any evidence that any of the
fuel-air mixers of the applied prior art experienced coking problems. While Ekstedt
does discuss the problem of coking in his discussion of prior art nozzles, Ekstedt
teaches (column 4, lines 19-23) that his combustion system is highly effective in
preventing carbon buildup on fuel nozzles. Since the examiner has not set forth any
evidence that Koshoffer's venturi suffers from coking, there is no reason for a person of
ordinary skill in the art at the time the invention was made to have modified Koshoffer's
system to prevent coking on the venturi. Moreover, Shekleton does not teach or
suggest an air passage wherein purge airflow is discharged into the venturi substantially
parallel to the longitudinal axis of the venturi sufficient to provide a boundary layer of air
along the inner surface of the wall of the venturi. The airflow discharged from
Shekleton's air assist tube 34 while flowing into the venturi 26 substantially parallel to
the longitudinal axis of the venturi is not sufficient to provide a boundary layer of air
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