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Roller grinding mill apparatus

  • US 4,022,387 A
  • Filed: 03/12/1976
  • Issued: 05/10/1977
  • Est. Priority Date: 03/12/1976
  • Status: Expired due to Term
First Claim
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1. Roller grinding mill apparatus comprising a frame enclosing a space in which material to be ground is confined, a stationary bull ring fixed in said frame in position to have an inwardly presented cylindrically shaped grinding face, a plurality of grinding rollers in said enclosing space, means operably mounting said rollers for rotation about a common axis centered to said cylindrically shaped grinding face and for pivotal movement about axes perpendicular to said common axis of rotation and in planes parallel to said common axis of rotation and in radial directions toward and away from said grinding face, said operable mounting means providing for free movement of said grinding rollers away from said grinding face and limiting the radial movement toward said grinding face to a predetermined minimum gap spacing between said rollers and said grinding face without any material to be ground between said grinding rollers and said grinding face, and consisting in levered means and resilient elements to set said predetermined minimum gap spacing between said rollers and said grinding face in which said levered means is a hanger pendently supporting each rollers for pivotal movement in said planes parallel to said common axis and a lever arm on each hanger having a free end, and the resilient elements being located adjacent each lever arm free end in position to check lever movement thereby maintaining said gap spacing, means on said frame to admit material to said enclosing space above said bull ring, said material working down by gravity between said bull ring and grinding rollers to establish a layer of material of such thickness as to space said rollers from said bull ring face a distance greater than said minimum gap spacing, drive means connected to rotate said roller mounting means to generate a centrifugal force proportional to the speed of rotation urging said grinding rollers toward said grinding face whereby said operable mounting means permits said rollers to be free to move radially limited only by said minimum gap spacing, and air supply means on said frame including an air receiving bustle and ports opening between said bustle and the enclosing space in said frame below said bull ring, said ports directing air into the material to fluidize the material being ground.

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