Patents Assigned to The Rubbright Group
  • Patent number: 5834744
    Abstract: An assembly for applying microwave irradiation to a load having a generally circular cross-section. The applicator supports a dominant TM.sub.120 mode and the load is aligned with a central axis in the applicator, with each aperture of a pair of feed apertures diametrically opposed (for the circular cross sectional case) or located on parallel opposed walls (for the polygonal cross sectional case) with one of the pair of feed apertures positioned at 90 degrees with respect to the other pair about the axis. The applicator may be formed as a cylinder or as a polygonal prism of the type having parallel opposed sides, such as those having a square, hexagonal or octagonal cross-section. Means such as a microwave transparent tube or conveyor provide for positioning of the load in the applicator. In an alternative embodiment, two cavities are used, with one cavity associated with each of the two feed systems, and a means for conveying the load from the first cavity to the second cavity is provided.
    Type: Grant
    Filed: September 8, 1997
    Date of Patent: November 10, 1998
    Assignee: The Rubbright Group
    Inventor: Per O. Risman
  • Patent number: 5828040
    Abstract: A microwave applicator of microwave reflective material having a closed first end, four side walls and, in a first embodiment, an open second end spaced apart from and facing a ground plate, the ground plate extending in a pair of transverse directions and having a longitudinal direction perpendicular thereto, and in a second embodiment, a closed second end, the applicator forming a cavity containing a desired hybrid mode having a low wave impedance in the longitudinal direction and an absence of an E field component in one of the transverse directions.
    Type: Grant
    Filed: May 31, 1995
    Date of Patent: October 27, 1998
    Assignee: The Rubbright Group, Inc.
    Inventor: Per O. Risman
  • Patent number: 5632921
    Abstract: A microwave applicator including a generally cylindrical microwave containment chamber, a microwave energy source, and a feed structure connecting the microwave energy source to the containment chamber. The diameter of the containment chamber is designed according to a process that need only take into account supporting a microwave pattern having substantially only two transverse magnetic modes, each with a characteristic guide wavelength, where the guide wavelength of one mode is substantially equal to twice the guide wavelength of the other mode. Additionally, the interior diameter can be sized to minimize the index subscript numbers of the transverse magnetic modes. The feed structure of the applicator includes at least two feed apertures spaced physically apart around the cylindrical axis of the applicator by a physical angle equal to an electrical phase shift angle of the microwaves introduced through the respective apertures, which in a preferred embodiment is 90 degrees.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: May 27, 1997
    Assignee: The Rubbright Group, Inc.
    Inventors: Per O. Risman, Charles R. Buffler
  • Patent number: 5396052
    Abstract: A utensil for use in preparing foods in a microwave oven comprises a microwave transparent, nonconductive, ceramic, opentop food receiving vessel, a microwave transparent, nonconductive, ceramic cover for closing the open top of the vessel, special glaze or coating sintered onto at least the interior surfaces of the vessel and cover or onto both the interior and exterior surfaces thereof; the glaze or coating being comprised of a dielectric matrix and semiconductive particles dispersed throughout the matrix; the percent loading of the conductive particles in the matrix being such that the food contained in the vessel is partially shielded from microwave energy and the glaze absorbs microwave energy and the glaze absorbs microwave energy and converts it to thermal energy concentrated at the utensil so that the outside surface of the food is browned and crisped and the food is cooked from the outside to the inside by the heat transferred to the food from the utensil, as well as being cooked in part from the ins
    Type: Grant
    Filed: January 21, 1993
    Date of Patent: March 7, 1995
    Assignee: The Rubbright Group, Inc.
    Inventors: Robert J. Petcavich, Gregory A. Kaiser