Appeal No. 2007-0886
Application 09/914,181
Appellants’ invention relates to a process for producing an acoustical
attenuating panel for use, for example, in the attenuation of noise arising
from aircraft turbo motors (Specification 1:5-10). The panel has four main
parts positioned in the following order: a layer with structural properties, a
layer with acoustical properties, a cellular structure and a reflector (Br. 2).
The first two layers form a single sheet after polymerization and are referred
to collectively as the “acoustically resistive layer.”
Independent claim 9 is illustrative of the invention:
9. Process for the production of an acoustical attenuating panel
comprising a cellular structure covered on one side with a reflector and on
the other side with an acoustically resistive layer with two components
respectively with an acoustical property and with a structural property,
which process comprises the following steps:
- emplacing on a mold of a shape appropriate to the panel to be
obtained, a layer with structural properties, constituted by filaments pre-
impregnated with a thermoplastic or thermosetting resin, by draping,
winding or wrapping said filaments while spacing the latter, such that said
layer has a quantity of open surface of the order of 30% of the total surface
of the exposed layer,
- emplacing from above the layer with structural properties, a layer
with acoustical properties, constituted by a microporous cloth of mineral or
organic fibers a thickness of the order of a tenth of that of the layer with
structural properties;
- then emplacing the cellular structure and the reflector, and
- performing at least one step of baking in an autoclave at the end of at
least one of the said steps of emplacing.
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