Appeal No. 1997-3304 Page 6
Application No. 08/181,936
cells 41 making it harder to purge the tube when changing from
one gas flow to another" (col. 5, lines 22-25). The solution
described by Philipossian is that "the optimum shape for
suppressing re-circulation cells of entering reactant gases is
obtained by increasing the curvature of...[the] sidewalls of
the nozzle in the direction of theoretical flow streamlines"
(col. 5, lines 41-45). Whereas Philipossian does discuss a
gas flow problem at the entry of the furnace, the patentee
does not discuss the processing of the spent furnace gas much
less suggest that there is any problem with gas flow into a
trap for collecting chemical by-products from the spent
furnace gas.
It is the examiner's view that
[i]t would have been obvious to one of ordinary skill in
the art to modify the inlet and outlet gas flow pipes of
Japan '833 with the conical-like shape (40) of
Philipossian... [t]he motivation being that the conical-
like shape would enhance the gas flow's pressure along
with being less susceptible to breakage (answer, page 4).
We do not see that the particular combination of the
prior art references as relied upon by the examiner teaches or
suggests a chemical vapor deposition trap like that claimed by
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