Appeal No. 1999-1778
Application No. 08/888,365
than that of the tip of the inner fins, wherein the
cross-sectional shapes of the convex portion and the
inner fins are asymmetrical so that the flow
resistances are different for different flow
directions of a refrigerant through the tube.
[Emphasis added.]
Fujimoto, the primary reference in the examiner’s
rejection, is similar to appellants’ heat exchanger tube is the
sense that both have internal ribs, and in the sense that both
are designed to be mounted in holes of thin metal sheets by an
expansion process that includes forcing a mandrel through the
tubes to mechanically expand them into tight engagement with the
holes of the sheets. Further, both Fujimoto and appellants
provide a relatively large convex portion (appellants’ element
(7), Fujimoto’s element (6)) on the inner surface of the tube
for the purpose of taking up expansion forces of the mandrel and
preventing the smaller, more delicate inner fins (appellants’
element (9), Fujimoto’s element (7)) from being detrimentally
deformed by the mandrel. See, for example, the paragraph
spanning pages 5 and 6 of the attached translation of Fujimoto.
Booth, the secondary reference in the examiner’s rejection,
also pertains to an internally ribbed heat exchanger tube that
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