Appeal No. 1997-3304 Page 5
Application No. 08/181,936
Claim 1 is exemplary and recites,
A chemical vapor deposition trap, comprising:
a chamber for collecting chemical by-products, said
chamber having an inlet coupled for receiving a vapor
including said chemical by-products; and
a first pipe having an inlet coupled for receiving said
vapor at a first pressure, said first pipe having an outlet
coupled to said inlet of said chamber where said outlet of
said first pipe is tapered to reduce said first pressure of
said vapor before entry into said chamber.
Japan'833 (Fig. 1) teaches a chemical vapor deposition
trap (9) and a pipe outlet coupled to the trap inlet, but does
not teach or suggest that the pipe outlet is tapered or that
there is any problem with gas flow into the trap.
Philipossian teaches a cone-like shaped inlet (40) to a
furnace (Fig. 1) which is used in conjunction with an annular
manifold around the furnace exit to produce an inert gas
barrier that prevents ambient gas from entering the furnace.
The cone-like shaped inlet (40) "suppresses the formation of
re-circulation gas cells 41," making it easier to purge the
furnace tube (10) (col. 5, lines 19-20). The problem
described by Philipossian is that "the flow of gas passing the
sharp corners of the inlet of FIG. 8 results in circular gas
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