Patents by Inventor Donald K. Ratcliffe

Donald K. Ratcliffe 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: 5416795
    Abstract: A crucible assembly for use in induction melting furnaces utilizes an inner crucible formed of partially stabilized zirconia and an outer support member formed of a sintered alumina. The crucibles are in the shape of a cylinder with a closed bottom wall and in the cylindrical wall area, the inner crucible and the outer support member are separated by a layer of porous ceramic fibers of alumina and silica and the entire assembly has been centered as a unit so that the outer support member with a porous layer allows for the thermal expansion and contraction of the inner crucible while limiting any stresses applied to the inner crucible and providing additional strength and support for the inner crucible.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: May 16, 1995
    Inventors: John A. Kaniuk, Crispino DiRuggiero, Donald K. Ratcliffe