Improvements in lead oxide mills

摘要

Lead oxide is produced in a mill comprising a stationary casing, within which is mounted a perforated rotary drum which in operation is charged with pieces of lead to be tumbled in a stream of air to produce said oxide, wherein the said casing is adapted for connection to a source of air and an air distribution means is located within the casing below the drum for distributing the air entering and flowing through the casing over substantially the full length and width of the drum. Fig. 2 illustrates diagrammatically a suitable mill in which casing 1 contains perforated drum 4 mounted for rotation about shaft 12. Below the drum and air inlet pipe 7 connects to a V-shaped manifold 8, fastened to the side of the casing by flanges 10. At right angles to manifold 8 are a series of spaced cross tubes 9, having a cross-section as shown in Fig. 3, with air outlets 11 on the underside. Tubes 9 run the full length of the drum and leave the casing via a similar manifold and air outlet pipe on the other side. The upper part 3, of casing 1, has an inclined conical shape, inclined against the rotation of the drum and serving as a baffle to prevent any particles which may be entrained in the air stream from reaching outlet 5. The oxide produced falls through the perforated drum, past the steeply inclined sides of tubes 9 and is collected in conical section 2 for discharge at outlet 6. Air inlet pipe 7 may be fitted with a damper to control the air flow and hollow shaft 12 may be fitted with a Venturi or other measuring device to measure the flow of air through drum 4.