Patents by Inventor Walter F. Stewart

Walter F. Stewart 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).

  • Process to remove actinides from soil using magnetic separation
    Patent number: 5538701
    Abstract: A process of separating actinide-containing components from an admixture including forming a slurry including actinide-containing components within an admixture, said slurry including a dispersion-promoting surfactant, adjusting the pH of the slurry to within a desired range, and, passing said slurry through a pretreated matrix material, said matrix material adapted to generate high magnetic field gradients upon the application of a strong magnetic field exceeding about 0.1 Tesla whereupon a portion of said actinide-containing components are separated from said slurry and remain adhered upon said matrix material is provided.
    Type: Grant
    Filed: February 28, 1994
    Date of Patent: July 23, 1996
    Assignee: The Regents of the University of California, Office of Technology Transfer
    Inventors: Larry R. Avens, Dallas D. Hill, F. Coyne Prenger, Walter F. Stewart, Thomas L. Tolt, Laura A. Worl
  • Magnetic refrigeration apparatus with belt of ferro or paramagnetic material
    Patent number: 4704871
    Abstract: A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.
    Type: Grant
    Filed: April 3, 1986
    Date of Patent: November 10, 1987
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: John A. Barclay, Walter F. Stewart, Michael D. Henke, Kenneth E. Kalash
  • Magnetic refrigeration apparatus with conductive heat transfer
    Patent number: 4702090
    Abstract: A magnetic refrigerator has a rotating magnetic wheel which includes a stack of spaced rings of magnetic material. Heat transfer plates of a high temperature heat extractor are interleaved with the magnetic rings and extend to a solid heat transfer conduit which leads to a high temperature terminal. Superconducting magnet coils are mounted to provide a magnetic field through the magnetic wheel at the position of the high temperature heat transfer plates. Low temperature extractor heat transfer plates are positioned outside of the magnetic field and interleave with the rings of the magnetic wheel to transfer heat thereto which is conducted from a low temperature terminal through a solid conduit.
    Type: Grant
    Filed: October 24, 1986
    Date of Patent: October 27, 1987
    Assignee: Astronautics Corporation of America
    Inventors: John A. Barclay, Walter F. Stewart, F. Coyne Prenger, Carl B. Zimm, John P. Parsons
  • Magnetic refrigeration apparatus and method
    Patent number: 4459811
    Abstract: The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.
    Type: Grant
    Filed: March 28, 1983
    Date of Patent: July 17, 1984
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: John A. Barclay, William C. Overton, Jr., Walter F. Stewart