A spray drying chamber with an air barrier system has been developed for the purpose of the deposit-free operation of the spray drying of a Kampo (chinese herb) extract. The preventive effect of the air barrier system on depositon on the chamber wall during spray drying operations was studied in comparison with a hammer and air-broom system using a liquid with 20% solid which is adhesive to the chamber wall.
The amount deposited on the test plates placed on the chamber wall using the air barrier system was smaller than the other preventive systems, hammer and air-broom. The recovery of solids by spray drying using a drying chamber with the air barrier system was 65%. On the other hand, the recovery of solids using the drying chamber with hammer and air-broom was 31% and 39%, respectively, under operating conditions.
These results showed that the spray drying chamber with an air barrier system was the most effective method of the other preventive systems for the prevention of deposition on the chamber wall.

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In order to analyze the flow behavior of particles by the application of continuum mechanics, a new constitutive equation is derived from considerations of energy dissipation during the flow of the particles. This dissipation mechanism was investigated by computer simulation of the flow behavior of particles on an inclined trough. The energy of flowing particles is dissipated by friction and collision with neighboring particles. The constitutive equation was derived by considering both dissipation mechanisms of energy. The velocity distribution of flowing particles on the inclined trought was estimated by the application of a constitutive equation. The estimated velocity distribution agrees well with the measured one.

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The effect of packing conditions on the pressure of a fine powder in a bin was examined. As the results of filling experiments of a fine powder through the sieves with different openings, it is confirmed that the powder pressure and the charge of a fine powder in a bin are influenced by the packing conditions. The reason is that the mechanical properties of a fine powder change considerably with the packing conditions, i. e., normal stress acting on the bed, the condition of agglomerating, the structure of packing, the rate of filling, and so on. The pressure and the charge of a fine powder in a bin can be estimated by Janssen's equation using the mechanical properties depending on the packing conditions.

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It is known that pressure fluctuation produces an error in flow volume. Many researchers tried to remove the pressure fluctuation by using a surge-tank, thus the effect of the surge-tank was investigated. However, their research was insufficient to explain the characteristics of the local pressure fluctuation damping process and the error in the flow volume of the gas solid suspension flow system in the pipe. First, the author used a surge tank and heat exchanger to damp on the pressure fluctuation. The pressure fluctuation at the local position of air flow was by a memory recorder, and the flow volume was measured by a quarter circle nozzle. Then, the characteristics of pressure fluctuation damning and the error in the flow volume were analysed.

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Granulation in the powder metallurgy and the ceramics industries is a common operation. However, the granules produced by conventional methods of granulation, e. g. spray drying, frequently have a drawback in formability owing to their excessively large strength.
To develop a new process for the granulation of cohesive fine powder, granulation without a binder is investigated in spouted beds with three different taper angles. The produced granules are found to have a moderate strength such that they break down under slight finger pressure but never disintegrate during a sieving operation. Furthermore, the mean diameter of the granule increases slightly with the operation time and is not affected considerably by the fluidization gas velocity. Also there is a range of the taper angle in which granulation is impossible. Moreover, it is pointed out that a kind of spatula angle is an important factor in granulation.

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It is important to investigate theoretically and/or experimentally pressure drop or scale-up techniques in a plug-phase conveyance line. However, there is little in the literature which discusses in detail the effect of pipe diameter and length on the pressure drop, or simple scale-up procedures in practical large scale conveyance lines.
In this paper, plug-phase conveyance experiments of cohesionless coarse particles were carried out, by making use of 25A-80A pipe lines, the length of which was max. 100m long.
Moreover, a simple scale-up method in plug-phase conveyance lines was proposed on the basis of Les, eq. (1) and ΔP_T/L, eq. (13)-(17).

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