TABLE OF CONTENTS All the above considerations relate to equilibrium classification, i.e. to flows in hollow circular or rectangular pipes. Until recently, one of the controlling factors of organisation of high efficiency separation was assumed to be the best possible homogeneity of the classification conditions. This means that the sufficient efficiency of separation in a hollow body apparatus may be obtained only if it is relatively long (high). However, the practice of recent years shows that in some types of perturbation of the flow, it is possible to obtain a strong effect in apparatus of small height.
To explain this problem, special investigations were carried out. For this purpose, specialised equipment, Fig. VI-1, was developed.
The main element of equipment is a vertical pipe with a diameter of 150 mm, height 7 m. The pipe consists of eight separate sections (1) with a height of 800 mm, connected together with flanges (2) with built-in rapidly acting gates (3). The movement of each gate and rapid overlapping of the pipe channel are carried out by means of a spring and counterweight (4). When rotating the controlling lever, the common connecting rod (5) rotates the latches of the gate (6) and they simultaneously and rapidly overlap the cross-section.
Equipment operates under a rarefaction generated by the valve (8). The air flow rate is measured with a...
