Appeal No. 2003-1379
Application No. 09/769,334
remedy this deficiency, the examiner relies on the disclosure of
Allen. We, like the examiner, find that Allen teaches filling
the interior of a fuel tank having a volatile fuel with an open
cell polyurethane foam. See column 4, lines 8-64. According to
Allen (column 4, lines 32-46):
It [foam] does not substantially increase weight, which
is an important factor in aviation application. The
geometry and size of the cells is [sic., are]
important. The reticulated structure keeps flame
propagation from reaching the velocity necessary for
explosion. It dissipates some of the heat generated at
ignition and the foam operates as a heat sink so as to
provide a cooling action. The skeletal strands break
up the compression wave that precedes a flame front in
explosion. Furthermore, the skeletal structure absorbs
energy from the initial contained explosion.
Therefore, the cellular structure absorbs, divides and
dissipates energy, whether the energy is thermal or
physical compression, heat, or explosion. The
structure also provides the foam with an unusual
weight-bearing and stress-distributing property.
(Emphasis added).
Given the above safety advantages in employing an open cell
polyurethane foam in an aircraft fuel tank, we determine that one
of ordinary skill in the art would have been led to at least
partially fill the aircraft fuel tanks taught in Beuck with an
open cell polyurethane foam having appropriate cell sizes,
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