Patents by Inventor James W. Klett

James W. Klett 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).

  • Publication number: 20020141932
    Abstract: A thermally conductive carbon foam is provided, normally having a thermal conductivity of at least 40 W/m·K. The carbon foam usually has a specific thermal conductivity, defined as the thermal conductivity divided by the density, of at least about 75 W·cm3/m·° K·gm. The foam also has a high specific surface area, typically at least about 6,000 m2/m3. The foam is characterized by an x-ray diffraction pattern having “doublet” 100 and 101 peaks characterized by a relative peak split factor no greater than about 0.470. The foam is graphitic and exhibits substantially isotropic thermal conductivity. The foam comprises substantially ellipsoidal pores and the mean pore diameter of such pores is preferably no greater than about 340 microns. Other materials, such as phase change materials, can be impregnated in the pores in order to impart beneficial thermal properties to the foam.
    Type: Application
    Filed: January 29, 2002
    Publication date: October 3, 2002
    Inventors: James W. Klett, Timothy D. Burchell, Ashok Choudhury
  • Patent number: 6399149
    Abstract: A process for producing a carbon foam heat sink is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications. The foam is encased and filled with a phase change material to provide a very efficient heat sink device.
    Type: Grant
    Filed: January 24, 2000
    Date of Patent: June 4, 2002
    Assignee: UT-Battelle, LLC
    Inventors: James W. Klett, Timothy D. Burchell
  • Patent number: 6398994
    Abstract: A process for producing molded pitch based foam is disclosed which minimizes cracking. The process includes forming a viscous pitch foam in a container, and then transferring the viscous pitch foam from the container into a mold. The viscous pitch foam in the mold is hardened to provide a carbon foam having a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: June 4, 2002
    Assignee: UT-Battelle, LLC
    Inventor: James W. Klett
  • Patent number: 6387343
    Abstract: A process for producing carbon foam or a composite is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications.
    Type: Grant
    Filed: August 19, 1998
    Date of Patent: May 14, 2002
    Assignee: UT-Battelle, LLC
    Inventor: James W. Klett
  • Publication number: 20020023858
    Abstract: A method and apparatus for extruding pitch based foam is disclosed. The method includes the steps of: forming a viscous pitch foam; passing the precursor through an extrusion tube; and subjecting the precursor in said extrusion tube to a temperature gradient which varies along the length of the extrusion tube to form an extruded carbon foam. The apparatus includes an extrusion tube having a passageway communicatively connected to a chamber in which a viscous pitch foam formed in the chamber passes through the extrusion tube, and a heating mechanism in thermal communication with the tube for heating the viscous pitch foam along the length of the tube in accordance with a predetermined temperature gradient.
    Type: Application
    Filed: October 18, 2001
    Publication date: February 28, 2002
    Inventor: James W. Klett
  • Patent number: 6344159
    Abstract: A method and apparatus for extruding pitch based foam is disclosed. The method includes the steps of: forming a viscous pitch foam; passing the precursor through an extrusion tube; and subjecting the precursor in said extrusion tube to a temperature gradient which varies along the length of the extrusion tube to form an extruded carbon foam. The apparatus includes an extrusion tube having a passageway communicatively connected to a chamber in which a viscous pitch foam formed in the chamber paring through the extrusion tube, and a heating mechanism in thermal communication with the tube for heating the viscous pitch foam along the length of the tube in accordance with a predetermined temperature gradient.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: February 5, 2002
    Assignee: UT-Battelle, LLC
    Inventor: James W. Klett
  • Publication number: 20010049020
    Abstract: A process for producing carbon foam or a composite is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications.
    Type: Application
    Filed: July 11, 2001
    Publication date: December 6, 2001
    Inventor: James W. Klett
  • Patent number: 6287375
    Abstract: A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: September 11, 2001
    Assignee: UT-Battelle, LLC
    Inventor: James W. Klett
  • Patent number: 6261485
    Abstract: A process for producing carbon foam or a composite is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: July 17, 2001
    Assignee: UT-Battelle, LLC
    Inventor: James W. Klett
  • Publication number: 20010003576
    Abstract: The present invention discloses a method for molding complex and intricately shaped high density monolithic carbon, carbon-carbon, graphite, and thermoplastic composites using gelcasting technology. The method comprising a polymeric carbon precursor, a solvent, a dispersant, an anti-foaming agent, a monomer system, and an initiator system. The components are combined to form a suspension which is poured into a mold and heat-treated to form a thermoplastic part. The thermoplastic part can then be further densified and heat-treated to produce a high density carbon or graphite composite. The present invention also discloses the products derived from this method.
    Type: Application
    Filed: December 19, 2000
    Publication date: June 14, 2001
    Inventors: James W. Klett, Mark A. Janney
  • Patent number: 6037032
    Abstract: A process for producing a carbon foam heat sink is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications. The foam is encased and filled with a phase change material to provide a very efficient heat sink device.
    Type: Grant
    Filed: June 8, 1998
    Date of Patent: March 14, 2000
    Assignee: Lockheed Martin Energy Research Corp.
    Inventors: James W. Klett, Timothy D. Burchell
  • Patent number: 6033506
    Abstract: The process obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications.
    Type: Grant
    Filed: September 2, 1997
    Date of Patent: March 7, 2000
    Assignee: Lockheed Martin Engery Research Corporation
    Inventor: James W. Klett
  • Patent number: 5871838
    Abstract: A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50.degree. C. for 14 hours and hot pressed at 2000 psi at 400.degree. C. for 3 hours. The hot pressed part is carbonized at 650.degree. C. under nitrogen for 3 hours and graphite at 2400.degree. C. to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc.
    Type: Grant
    Filed: December 30, 1996
    Date of Patent: February 16, 1999
    Assignee: Lockheed Martin Energy Systems, Inc.
    Inventors: James W. Klett, Timothy D. Burchell, Jeffrey L. Bailey
  • Patent number: 5744075
    Abstract: A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50.degree. C. for 14 hours and hot pressed at 2000 psi at 400.degree. C. for 3 hours. The hot pressed part is carbonized at 650.degree. C. under nitrogen for 3 hours and graphitized at 2400.degree. C. to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: April 28, 1998
    Assignee: Martin Marietta Energy Systems, Inc.
    Inventors: James W. Klett, Timothy D. Burchell, Jeffrey L. Bailey
  • Patent number: 5334414
    Abstract: The present invention is directed to a process for coating carbon fibers with a pitch material. The process employs a pressurized air-comb for spreading a carbon fiber tow into individual carbon fiber filaments and providing the carbon fiber filaments in a spreaded tow to a powder deposition chamber. A pitch material is dried and finely ground and is then fed into the coating chamber at a point above the traveling spreaded carbon fiber tow. The pitch powder initially falls onto the fiber tow and begins forming a uniform coating around the individual carbon fibers. After falling past the point of the traveling carbon tow, the pitch powder is then recirculated back to the upper portion of the coating chamber and is entrained within a pitch powder cloud through which the threaded fiber tow travels. Fibers that are coated by such a method may be used to form carbon/carbon composites that exhibit high strength and excellent mechanical properties.
    Type: Grant
    Filed: January 22, 1993
    Date of Patent: August 2, 1994
    Assignee: Clemson University
    Inventors: Danny D. Edie, James W. Klett