Closed loop control of a pneumatic conveying system using tomographic imaging

The subject of pneumatic conveying of solids is a complex one. The flow regime present in a conveying system is dependent upon: the size and shape of the particles to be conveyed, the geometry and orientation of the conveying pipe, the relative densities of the solid and the conveying air. The variable parameters present are the velocity of the conveying air and the solids mass flow rate. The variation of these two factors dictates the presence of either dilute or dense phase flow, At Manchester Metropolitan University a pneumatic conveying system, transporting polyethylene nibs, was used to investigate the implementation of a proportional and integral control system using a tomographic imaging system in the feedback loop. The aim of the investigative work was to achieve control of the air velocity and solids loading factor for the conveying system to maintain dilute phase flow at a prescribed dune level. The solids material conveyed was sensed using a PC based electrical tomographic imaging system and this was used to control the air velocity in the conveying system. (C) 2001 SPIE and IS&T.