WAYS OF IMPROVING PNEUMATIC TRANSPORT THROUGHPUT
S. Ya. Davydov,
G. G. Kozhushko,
I. D. Kashcheev,
and V. A. Matafonova
Translated from Novye Ogneupory, No. 4, pp. 26 – 30, April 2011.
Original article submitted September 18, 2010.
Comparative equipment indices are given for transporting cement. An operating principle is proposed for a
chamber feeder without aeration devices, i.e. with use of an injector for compressed air supply from openings
directed at the bottom of the reception chamber. Material movement is demonstrated over an inclined plane
with charging of a chamber feeder. Injector channel length, the dependence of channel length on its inclination
and width of the sprayer channel slot, are determined.
Keywords: chamber feeder, injector, compressed air, speed, inclination, material particle, channel length.
Typical loose material properties affect transportation
and storage processes; particle size, density, bulk density, in-
ternal friction coefficient, friction coefficient over solid sup-
port surfaces, natural repose angle, moisture content, particle
mobility and bonding, settling, abrasiveness, and particle
shape. As a rule, pneumatic transport is used for fine materi-
als with the maximum size a not exceeding 10 mm. The fol-
lowing classification is adopted in loose material load me-
chanics: coarse-grained (2 < a ^ 10 mm), fine-grained
(0.5 < a < 2.0 mm), powder (0.05 < a ^ 0.5 mm), and dust
(a < 0.05 mm).
Pneumatic transport of loose materials through pipes is
used extensively in view of its simplicity, reliability, sealing,
independence from weather conditions, the possibility of to
tal automation, comparatively small metal content and capi
tal expenditure, etc. Optimum functioning of pneumatic
transport systems is determined by the minimum expenditure
of energy with a prescribed productivity for a material under
conditions of stable transport capacity, with which there no
deposition of particles in a pipeline. A marked disadvantage
of pneumatic transport is the increased consumption of elec
trical energy compared with a mechanical form of transport,
for example conveyer (see Table 1) .
Operation of chamber pumps with upper delivery of ma
terial, fitted with plant manufacturer injectors, has demon
strated their low operational reliability. A high moisture con
tent of compressed air and the cyclic nature of pump opera
tion leads to the situation that, by mixing with condensate, it
settles on the metal parts, gradually blocking the delivery
opening of an injector. This leads to powder falling into an
air main line, which is also entirely blocked. In order to pre-
vent material falling into the gas distribution chamber each
nozzle of an injector is made in the form of an elbow. In
other versions the axes of channels are inclined to the hori-
zontal at a certain angle or a circular groove, communicating
with the air supply channels, covered with an elastic nipple.
Apart from this, devices are known with use of springs,
which complicate the injector construction.
Recently in our country and abroad numerous proposals
have appeared for improving the construction of chamber
feeders, although in the majority of cases these proposals are
of a speculative nature. Results are provided of testing the
unloading cycle of a chamber feeder by G. M. Ostrovskii 
(Fig. 1), which indicated funnel-shaped movement of mate
rial in a chamber feeder over the vertical of the transport
pipeline with exposure of its inlet connection. With caving of
funnel slopes pressure in the feeder becomes insufficient, in
order to propel material into the pipeline, there is obstruc
tion, which is reflected as an increase in compressed air flow
With an increase in pressure in the feeder, air is filtered
in the material and compaction occurs both from above
downwards, and from the boundary of the material mixing
zone with the side walls of the chamber feeder. Apparently at
the bottom of the feeder and at its walls material will be most
dense. Analysis for reasons for a reduction in the operating
reliability of injectors, and as consequence, the chamber
pump itself, indicates that it is necessary to find a method in
order that powder does not fall within the injector and in the
air main line of compressed air feed to the injector.
Refractories and Industrial Ceramics Vol. 52, No. 2, July, 2011
1083-4877/11/05202-0126 © 2011 Springer Science+Business Media, Inc.
FGAOUVPO B. N. El’tsin Ural federal University, Ekaterinburg,
OAO Uralgiprotyazhmash, Yekaterinburg, Russia.