Appeal No. 2004-0540 Page 4
Application No. 09/601,237
shortened in the length dimension of the cross section relative to the cross section of
the body portion. Unlike appellant’s tube, however, each tube of Potier and Le Gauyer
‘832 defines only a single longitudinal flow channel, rather than being formed by a strip
of metal folded so as to define two longitudinal flow channels. In essence, two of the
tubes of Potier and Le Gauyer are needed to provide the two flow channels defined by
the tube recited in appellant’s claim 1.
Nonogaki (note Figure 4), Le Gauyer ‘221 (note Figure 3) and Martins disclose
heat exchanger tubes, with each tube being formed by a single strip of sheet metal
folded so as to define two longitudinal flow channels and a reinforcing spacer as called
for in claim 1. Le Gauyer ‘221 points out that a main drawback of heat exchangers that
bundle pairs of tubes is the requirement for insertion of tubes of the same pair in one
hole of the collecting plate, thereby complicating the assembly (translation, page 2).
The tubes of these references, however, appear to be of substantially constant cross
section and thus lack the header region having a cross section dilated in the width
dimension and shortened in the length dimension relative to a body portion.
In rejecting the claims, the examiner’s position is that it would have been obvious
to one of ordinary skill in the art to employ in Potier or Le Gauyer ‘832 a tube formed by
a strip of folded sheet metal having two longitudinal flow channels for the purpose of
ease of manufacture and assembly, as recognized by Nonogaki, Le Gauyer or Martins
(answer, page 6). Appellant points out that each of the secondary references,
Nonogaki, Le Gauyer ‘221 and Martins, is exclusively limited to flat tubes which maintain
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