Distribution of feed onto a screening machine

In a screening machine having a screen, an improved feed distributor for distributing infed material over said screen, said improved distributor comprising,

• a dish-shaped, concave thrower, said thrower mounted above said screen and positioned to receive a falling stream of infed material,
• a fixed shroud around said thrower, said shroud having a cross-sectional area which is larger than the area of said thrower but smaller than the surface area of said screen,
• said shroud being substantially cylindrical in configuration,
• said shroud surrounding said thrower inwardly of said peripheral edge of said roof,
• said thrower being mounted for rotation about a generally vertical axis at a rate such that infed material falling onto said thrower is slung outwardly from it and against said shroud by rotation of said thrower,
• means for rotating said thrower about said axis,
• and a roof positioned above said screen and below said shroud, said roof extending outwardly beyond the shroud so that infed material slung against said shroud drops from it onto said roof, said roof having a peripheral edge from which material on the roof will drop onto said screen, said roof presenting a series of vanes extending outwardly toward the peripheral edge thereof, said vanes positioned on said roof to direct material falling onto said roof from said shroud toward said peripheral edge in a predetermined angular distribution.

An improved method of distributing an off-center, non-vertical stream of particulate infed material over the screen of a screening machine, said improved method comprising the steps of

• discharging said material so that it falls onto a cup-shaped thrower above the screen,
• rotating said thrower at a rate such that said particles are slung upwardly and outwardly from said thrower,
• interrupting the travel of the particles thus thrown by the thrower by providing a wall around said thrower on which the particles impinge in flight, said wall causing the particles to drop downwardly as an annular stream,
• arresting the fall of said particles from said wall by interposing a roof below the wall and over said screen so that said particles fall onto said roof,
• directing the particles in desired angular directions on said roof,
• and discharging the particles thus directed from the roof onto the screen.

An improved method of distributing particulate infed material over the screen of a screening machine, said improved method comprising the steps of

• discharging said material so that it falls into a cup-shaped thrower above the screen,
• rotating said thrower at a rate such that said particles are slung outwardly from said thrower,
• dividing the material slung outwardly by the thrower into separate angular segments while it is traveling outwardly from the thrower,
• interrupting the outward travel of the particles thus thrown and divided by providing a wall around said thrower, said wall causing the particles to drop downwardly as an annular stream,
• arresting the fall of said particles on a roof over said screen,
• then conducting the particles in said angular segments in desired angular direction over said roof to different areas of said screen so that the infed material is fed to said different areas at rates per unit which are substantially uniform,
• and discharging the particles thus directed from the roof onto the screen.