Pneumatic transport system for flour - has fan operating at constant pressure differential for maximum efficiency

摘要

The pneumatic transport system for flour is fitted with a centrifugal separator (2). The mixture of flour and air arrives by the pipe (7) which runs tangentially into the conical chamber (4) at the inlet (8). The flour falls downwards whilst the air is drawn upwards through the central pipe (11) and flows through the throttle valve (13) to the outlet duct (15). A fan in the outlet duct maintains the circulation of air through the system. This fan operates most efficiently at a constant pressure difference. This constant pressure difference is maintained by a flexible diaphragm (34) with one side exposed to the outlet pressure (21) of the centrifugal separator and the other side to the inlet pressure. Any change in this pressure difference acts on the diaphragm which actuates the throttle valve (13) to maintain a constant pressure differential.