Appeal 2006-1847
Application 10/295,813
DECISION ON APPEAL
STATEMENT OF THE CASE
This is an appeal from the final rejection of claim 25 and the
examiner’s refusal to allow claims 1, 4-7, 9-13 and 20 as amended after final
rejection. These are all of the claims remaining in the application.
The claimed invention is directed to a heat exchanger tube with
integral outer fins and an integral interior structure made up of small
pyramids or frustums.
Claim 1, reproduced below, is further illustrative of the claimed
subject matter.
1. A heat exchanger tube comprising plain ends, at least one structured
area on the outside of the tube and inside of the tube, having the following
characteristics:
a) integral outer fins extending helically over the
outside of the tube;
b) integral inner fins extending axis-parallel or
helically at a helix angle α = 0 to 70°, measured against an
axis of the tube, with primary grooves on the inside of the
tube;
c) the inner fins being intersected by secondary grooves
extending at a helix angle β measured against the tube axis;
d) the secondary grooves extending with respect to the inner fins at
an angle of intersection in a range of 60° to 85°;
e) the depth T of the secondary grooves being at least
20% of a fin height H of the inner fins; and
f) the density of intersecting points of the primary and
secondary grooves being in a range of 90 to 250 intersecting
points/cm2.
2
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