Patents by Inventor Donald A. Longhurst

Donald A. Longhurst has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7971815
    Abstract: A milling station and a method for grinding milling material using at least one coarse grinding circuit and at least one fine grinding circuit. The coarse grinding circuit includes a classifier and a material bed roller mill. The fine grinding circuit includes a tube mill with at least two grinding chambers, a central outlet, and a divider. In some instances, at least some of the milling material from the coarse grinding circuit is subdivided in the divider and delivered to the at least two grinding chambers of the fine grinding circuit while some of the milling material is jointly discharged from the at least two grinding chambers through the central outlet.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: July 5, 2011
    Assignee: Polysius AG
    Inventors: Ludger Schulte, Franz-Josef Zurhove, Donald A. Longhurst
  • Patent number: 7712611
    Abstract: Apparatus for separating particulate material into relatively fine and relatively coarse particles wherein such particulate material and a gas stream are introduced independently of one another to a separating zone through which the gas stream flows at such volume and velocity as to entrain fine particles and convey them from the separating zone to grinding or other facilities and wherein the fineness of entrained particles may be adjusted by diverting a selected portion of the gas stream from the separating zone to a bypass passageway followed by recombining the diverted portion of such gas stream with the gas containing the entrained particles.
    Type: Grant
    Filed: February 28, 2005
    Date of Patent: May 11, 2010
    Assignee: Polysius Corporation
    Inventors: Donald A. Longhurst, Franz-Josef Zurhove
  • Publication number: 20090020636
    Abstract: The invention relates to a milling station and a method for grinding milling material by means of at least one coarse grinding circuit (1) and at least one fine grinding circuit (2). The coarse grinding circuit is provided with a classifier (10) and a material bed roller mill (11). The precrushed material of the material bed roller mill is fed to the classifier whose coarse material is redirected to the material bed roller mill and whose fine material is delivered to the fine grinding circuit. The fine grinding circuit encompasses a tube mill (20) with at least two grinding chambers (20a, 20b), a central outlet (20c), and a divider (21). At least some of the milling material of the coarse grinding circuit is subdivided in the divider and is delivered to the two grinding chambers while the milling material is jointly discharged from the two grinding chambers via the central outlet.
    Type: Application
    Filed: February 14, 2006
    Publication date: January 22, 2009
    Inventors: Ludger Schulte, Franz-Josef Zurhove, Donald A. Longhurst
  • Publication number: 20050189262
    Abstract: Apparatus for separating particulate material into relatively fine and relatively coarse particles wherein such particulate material and a gas stream are introduced independently of one another to a separating zone through which the gas stream flows at such volume and velocity as to entrain fine particles and convey them from the separating zone to grinding or other facilities and wherein the fineness of entrained particles may be adjusted by diverting a selected portion of the gas stream from the separating zone to a bypass passageway followed by recombining the diverted portion of such gas stream with the gas containing the entrained particles.
    Type: Application
    Filed: February 28, 2005
    Publication date: September 1, 2005
    Inventors: Donald Longhurst, Franz-Josef Zurhove
  • Patent number: 6889843
    Abstract: Apparatus and methods for separating particulate material into relatively fine and relatively coarse particles wherein such particulate material is introduced to a separating zone through which a gas stream flows at such volume and velocity as to entrain fine particles and convey them from the separating zone to grinding or other facilities and wherein the fineness of entrained particles may be adjusted by diverting a selected portion of the gas stream from the separating zone to a bypass passageway followed by recombining the diverted portion of such gas stream with the gas containing the entrained particles.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: May 10, 2005
    Assignee: Polysius Corp.
    Inventors: Donald A. Longhurst, Franz-Josef Zurhove
  • Patent number: 5351894
    Abstract: The invention relates to a method and apparatus for the comminution of brittle material for grinding, particularly send-like material such as metallurgical sand in the roller gap of a material bed roller mill. In order to create an optimum capacity for drawing in the material for grinding in the roller gap, the material for grinding at the inlet to the roller gap is set to a (mixed) moisture content of approximately 0.3 to 3.0%, preferably approximately 0.5 to 2.0%.
    Type: Grant
    Filed: July 21, 1992
    Date of Patent: October 4, 1994
    Assignee: Krupp Polysius AG
    Inventors: Donald A. Longhurst, Norbert Patzelt