Ergonomics - Atlas Copco

vacuum-flow of the unit and the pressure
drop-flow for the system. In this plot the
vacuum and pressure drop are plotted on
one axis and the flow on the other. The
intersection is the balance or working point
for the system. It should be checked that the
flow at this point matches the recommended
flow for the tools used.
Oil control
Twenty years ago machine tool design-
ers began developing vanes that could run
against the cylinder wall without lubrica-
tion. This development was motivated by the
fact that oil used to lubricate the vanes was
emitted in aerosol form in the exhaust air. It
often entered the operator’s breathing zone,
and could cause harm by irritating the skin.
In some cases, female operators working on
assembly lines complained about the smell of
oil in their hair after a day’s work.
Development followed two paths. One
path was to create a more efficient lubrica-
tion system that could minimize the amount
of oil needed. The product is called Dosol.
The other path was to design a vane ma-
terial that did not require oil. Historically the
vanes were made of bakelite reinforced with
cotton fiber. The vanes run very fast along
the air motor cylinder wall and speeds of up
to 30 m/s are common. The forces between
the cylinder wall and the vane are high.
The friction coefficient must be kept low to
avoid high temperature and wear and this
has traditionally been done with oil. When
run completely dry, it was not uncommon for
vanes to have lifetimes of just minutes.
After extensive testing with customers
and in the laboratory, in 1990 new types
of vanes were introduced that require no
Modern turbine grinders can preferably
be run on non-lubricated air.
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