HIGHLY RELIABLE PNEUMATIC CONVEYOR
THAT FREELY DISCHARGES THE BULK MATERIAL
S. Ya. Davydov,
N. P. Kosarev,
and N. G. Valiev
Translated from Novye Ogneupory, No. 6, pp. 9 – 13, June, 2014.
Original article submitted December 24, 2013.
The article describes a steeply inclined pneumatic conveyor that transports alumina dust from electrostatic
precipitators to the receiving chamber of a rotary kiln in the calcination shop at OAO “BAZ-SUAL”. The dust
travels through the conveyor in a cascade motion. New equipment is proposed for the continuous transport of
bulk materials and relations are presented for determining the technical parameters of the conveyor.
Keywords: pneumatic conveyor, dispersing grates, diameter of the transport pipe, fluidized bed, separation
space, gas bubbles, discharge.
The OAO “BAZ-SUAL” has installed a steeply sloping
pneumatic conveyor that transports alumina dust from elec-
trostatic precipitators to the receiving chamber of a rotary
kiln in the calcination shop (Fig. 1) [1 – 7]. The dust travels
through the conveyor in a cascade motion. A recent reduction
in the velocities of gas-dust flows at the factory has in turn
reduced expenditures on cleaning the dust and gas. The bulk
material is transported at low velocities with a high concen
tration in the gas mixture, which means that the amount of
compressed gas that is used is also small.
Figure 2 shows one variant  for fabricating the trans
verse grates that disperse the flows inside the pipe of the con
veyor. Grates 11 and 12 of newly designed insert 8 are in
clined to the horizontal at an angle ranging from 4 to 8°. The
grates are inclined in the same direction as pipe 9. The angle
of inclination is regulated within ±2°. For each specific mate
rial that is transported, the same angle of inclination of each
grate a is maintained for different angles of inclination of the
pipe b relative to the vertical. Insert 8 can be composed of
In that case, grate 11 comprises one part of the insert and
is installed perpendicular to the main flow of the material-air
mixture. Grate 12 comprises the second part of the insert and
is inclined to the horizontal at an angle a between 4 and 8°.
This grate acts as an aerodynamic trough. Grate 12 is in-
clined in the same direction as the pipe.
The line 13 that coincides with the bend in the transverse
inserts can be moved. Fastener 7 can be used to help move
grates 11 and 12 laterally in the pipe. This changes their an-
gle of inclination by an amount within the range ±2°, the ex-
act angle depending on the bulk material being transported.
The principle followed in making holes 14 and 15 in grates
11 and 12 is similar to that used for grates 5 and 6 in vertical
The particles comprising the bulk material (load) slide
over the inclined surfaces of the grates in the same manner as
in an aerodynamic trough. The particles slide into the central
part of the pipe, which alleviates abrasive wear of its walls.
The material-gas flow eventually becomes uniform over the
entire cross section of the pipe. A decrease in the friction of
the material as it moves through the pipe reduces the amount
of energy that needs to be consumed to move it through the
conveyor. The height to which the material rises depends on
the pressure gradient, the number of additional inserts built
into the pipe, the number of holes in the inserts, and the di
ameter of those holes.
Thus, the presence of grates that are inclined to the hori
zontal at the angle a in the same direction as the pipe pre
vents movement of the material over the bottom wall of the
pipe. That reduces the probability of obstruction of the pipe
during service, which in turn makes the operation of the con
veyor as a whole more reliable. A decrease in the velocities
Refractories and Industrial Ceramics Vol. 55, No. 3, September, 2014
1083-4877/14/05503-0183 © 2014 Springer Science+Business Media New York
Ural State Mining University, Ekaterinburg, Russia.