US 4,282,090 AGranted

Rotary sifting device

AssigneeSt. Louis Conveyor Company, Inc.

InventorsAugust B. Hoernschemeyer, Alan L. Zinser, John F. Myers

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Abstract

A sifting or screening device includes inner and outer concentric screened enclosures which rotate about a common axis. An inlet is provided at one axial end of the inner enclosure and an outlet is provided at the opposite axial end of the enclosures for the material that was too large to pass through the openings defined by the screens. An inclined dead plate or baffle member is provided at the inlet to prevent material fed in through a chute from impinging directly on the screen material and a pressurized air system presents a pulsating curtain of air to disengage material which has become lodged in the screen. A novel support system includes a circular support surface at the inlet end which rides on a pair of bearings and a central axle coincident with the axis of rotation driven by a motor at the outlet end. The axis of rotation is caused to lie at a small angle to the horizontal so that material which will not pass through the screens will slowly fall toward the outlet end of the enclosures.

Claims12

Dependent claims

A rotary sifting device, comprising:

a disc mounted for rotation at a first end of said rotary sifting device;
a spider structure mounted for rotation at a second end of said rotary sifting device, said spider structure including a plurality of arms extending radially outwardly from a central hub;
a first screened enclosure mounted between said spider structure and said disc for rotation therewith, said first screened enclosure including a sizing screened portion;
a second screened enclosure mounted between said spider structure and said disc for rotation therewith and mounted concentrically inboard of said first screened enclosure, said second screened enclosure including a sizing screened portion and a baffle member portion, said baffle member portion defining an inlet for said rotary sifting device, said baffle preventing material entering said device at said second screened enclosure from impinging directly upon said second screened enclosure and for imparting rotational movement to said material prior to the introduction thereof onto the sizing screened portion of said second screened enclosure;
a pressurized air supply line having a plurality of nozzles directed radially inwardly toward said first screened enclosure, said nozzles including an outlet part axially aligned with each other outlet part of said nozzle plurality so as to direct a continuous axial air current radially inward of said first screened enclosure along the entire sizing screened portion of said first screened enclosure;
means for rotating at least one of said spider structure and said disc;
and
means for generating an air current through said nozzles to disengage material lodged in said first screened enclosure.

5 more elements

A rotary sifting device, comprising:

a disc mounted for rotation at a first end of said rotary sifting device;
a spider structure mounted for rotation at a second end of said rotary sifting device, said spider structure including a plurality of arms extending radially outwardly from a central hub;
a first screened enclosure mounted between said spider structure and said disc for rotation therewith, said first screened enclosure including a sizing screened portion;
a second screened enclosure mounted between said spider structure and said disc for rotation therewith and mounted concentrically inboard of said first screened enclosure, said second screened enclosure including a sizing screened portion and a baffle member portion, said baffle member portion defining an inlet for said rotary sifting device, said baffle preventing material entering said disc at said second screened enclosure from impinging directly upon said second screened enclosure and for imparting rotational movement to said material prior to the introduction thereof onto the sizing screened portion of said second screened enclosure;
a plurality of stabilizer members positioned and extending between said first and said second screened enclosures and joined thereto so as to permit relatively free flow of material between said first and second screened enclosures;
a pressurized air supply having a plurality of nozzles directed radially inwardly toward said first screened enclosure, said nozzles including an outlet part axially aligned with each other outlet part of said nozzle plurality so as to direct a continuous axial air current radially inward of said first screened enclosure along the entire sizing screened portion of said first screened enclosure;
means for rotating one of said spider structure and said disc;
and
means for generating an air current through said nozzles to disengage material lodged in said first screened enclosure.

6 more elements

A rotary sifting device, comprising:

a disc mounted for rotation at a first end of said rotarylsifting device;
a spider structure mounted for rotation at a second end of said rotary sifting device, said spider structure including a plurality of arms extending radially outwardly from a central hub;
a first screened enclosure mounted between said spider structure and said disc for rotation therewith, said first screened enclosure including a sizing screened portion;
a second screened enclosure mounted between said spider structure and said disc for rotation therewith and mounted concentrically inboard of said first screened enclosure, said second screened enclosure including a sizing screened portion and a baffle member portion, said baffle member portion defining an inlet for said rotary sifting device, said baffle preventing material entering said device at said second screened enclosure from impinging directly upon said second screened enclosure and for imparting rotational movement to said material prior to the introduction thereof onto the sizing screened portion of said second screened enclosure;
a plurality of stabilizer members positioned between said first and said second screened enclosures and positioned to permit reltatively free material flow between said first and second screened enclosures;
a pressurized air supply line having a plurality of nozzles directed radially inwardly along said first screened enclosure, said nozzles including an outlet part axially aligned with each other outlet part of said nozzle plurality so as to direct a continuous axial air current radially inward of said screened enclosure along the entire sizing screened portion of said first and said second screened enclosures;
means for rotating one of said spider structure and said disc;
means for generating an air current through said nozzles to disengage material lodged in said first screened enclosure;
and
bearing means for supporting said disc and the central hub of said spider structure, said first and said second screened enclosures being supported for rotation only along the central hub of said spider structure and said disc, said first and said second screened enclosures being coaxial about an axis offset from a horizontal plane at an angle between one and five degrees.

7 more elements

Dependencies are inferred from the claim text.