抄録
An Air Slide is a kind of pneumatic conveyor for transporting solid material through a slightly inclined trough.
The trough is separated into two parts by a horizontally placed porous plate. When low pressure air is blown into the lower channel, solid material, which is fed continuously on the upper channel, is aerated and flows like liquid.
Using an experimental equipment as shown in Fig. 1, we studied the mechanism of flow of materials through the trough. The characteristics of flow of standard sand, particles of alumina and bauxite were as shown in Fig. 8-11.
The velocity distribution was very different from that of the ordinary liquid, as shown in Fig. 12 and 13. Solid material slipped on the surface of the side wall of glass or steel plate. And the slip velocity was so large that the difference between the maximum velocity and the slip velocity was almost negligible for the purpose of designing the conveyor.
From this study, we concluded as follows:
(1) The coefficient of statical friction of aerated material decreases rapidly as the air velocity approaches the velocity of minimum fluidization Umf, and the solid material begins to flow at a very slight inclination.
(2) The flow rate of aerated material through an Air Slide can be represented as water flow in an open channel, and the resistance of flow is proportional to the mean velocity.
(3) By the use of the friction factor f or characteristic constant (such as ka) the dimension of an industrial equipment can be calculated.
