INVC (Industrial Noise &
Vibration Centre) has
applied aerodynamic noise
control technology to solve
the problem of the drone of
an extract system fan at Red
Bull Technology that was
creating a potential
environmental noise issue.

INVC says that while the
conventional technique used
to reduce fan tones like this is
a large, palliative silencer, that
doesn’t tackle the source of
the problem.

Instead, aerodynamic
inserts were designed, made
and installed inside the fan
casing within a pit-stop
window of a few hours. The
218Hz low frequency tone
was reduced by a factor of
around 1000, eliminating the
problem at source for the
lifetime of the fan, without
maintenance and without
affecting fan efficiency.

Terry Brice of Red Bull
Technology says: “The INVC
technique not only produced
a fantastic result, it’s also very
satisfying as an elegant
engineering solution”.