Appeal No. 98-2420
Application No. 08/573,854
efficient for use in mass manufacture, such as
for making many small holes in thin plates. A
reduction of the absolute pressure P to 3.7 bar
for a smallest diameter d of the blast pipe of
2
6 mm and a smallest diameter d of the HP-air
1
pipe of 4.5 mm, i.e. a ratio of 0.75, leads to a
power saving of approximately 45% compared with
a system operating at 7 bar with diameters of 6
and 3 mm, respectively.
It does have to be true for values
chosen for the absolute pressure P and the
ratio d /d that P<13.25-12.5 d /d because1 2 1 2
otherwise the underpressure in the mixing
chamber becomes too small with a higher P-
value for obtaining a sufficient venturi
action. It is even possible for a backflow
effect to occur.
A reduction in the operating pressure is
only possible, however, in that the transport of
the abrasive particles to the mixing device is
not dependent on the operating pressure.
Preferably, the transport machanism is a
vibratory mechanism. A vibratory transport
mechanism achieves that the abrasive particles
are evenly distributed during transport. Even
if the distribution should be irregular during
the entry of the particles from the hopper into
the vibrating conveyor of the vibratory
mechanism, the vibratory mechanism will ensure
that the particles are evenly distributed
nevertheless. An even distribution of the
particles leads to a constant inflow of
particles into the mixing chamber, and
contributes to a flow density of the mixture
issuing from the blast pipe which is as constant
as possible.
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Last modified: November 3, 2007