Separation of metal particles from fibres

摘要

Metal particles are removed from a fibre stream in a column in which one wall consists partly of a transport device. The fibres are taken past a row of metal sensors distributed across the column width. Based on signals provided by the sensors, corresponding local diverters prevent fibres from being drawn into a suction funnel placed at an angle to the transport device so that the metal particles reach a collector. Pref. fibres are separated from an air stream by a condenser (1) and fall through a vertical chute (2) on a compressing and transporting roller (3). The fibres pass metal sensors (5) which provide a signal to a controller (6) to activate air jets (8). Colour sensors (4) can also be fitted for colour separation of fibres at the same time. Valves (7) open the air supply to the jets (8) with an appropriate time delay to blow metal particles together with a small amount of fibre into the chute (11) to be collected in a container (12). Normal fibres are drawn off through a suction funnel (9) in an air suction stream (10) under the control of a slide valve (13). Heavy non-metallic particles, eg stones, also reach the container (12) because of their inertia.