Patents by Inventor David T. Hearst

David T. Hearst 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: 6652649
    Abstract: A crystal growth station including a cylindrical crucible having powered bottom and top resistance heaters mounted below and above the crucible, respectively. A supplemental heating unit is positioned around the bottom edge of the crucible. The supplemental heating unit may be unpowered or powered to heat it independently of the top and bottom heaters. If unpowered, then the supplemental heating unit is formed of a cylinder around the lower portion of the crucible side wall and a washer shaped disk member extending under part,of the crucible bottom wall. The supplemental heating unit is generally wedge shaped. The supplemental heating unit is heated by radiation from the bottom heater. The heat is conducted from the disk to the cylinder. A supplemental heater may be similarly used at the top edge of the crucible. If powered, the cylinder and the disk have slits therein to form current paths.
    Type: Grant
    Filed: June 19, 2001
    Date of Patent: November 25, 2003
    Assignee: ACT Optics & Engineering, Inc.
    Inventors: David T. Hearst, John Schupp
  • Patent number: 6602345
    Abstract: A furnace for growing a high volume of crystals includes a plurality of individual growth stations and first and second heater matrixes. Each individual growth station has a crucible and an insulating container generally surrounding the crucible and thermally isolating the crucible from the other individual growth stations. The first and second heater matrices each include at least two legs electrically connected in parallel and each of the legs have at least two resistance heaters electrically connected in series. Each of the individual growth stations have at least one of the resistance heaters within the first heater matrix and at least one of the resistance heaters within the second heater matrix associated therewith. The resistance heaters of the first heater matrix are located above the crucibles and are preferably adapted to provide a homogeneous temperature across tops of the crucibles.
    Type: Grant
    Filed: May 15, 2000
    Date of Patent: August 5, 2003
    Assignee: American Crystal Technologies, Inc.,
    Inventors: John D. Schupp, David T. Hearst
  • Patent number: 6562125
    Abstract: A furnace for growing a high volume of crystals includes a plurality of individual growth stations and first and second heater matrixes. Each individual growth station has a crucible and an insulating container generally surrounding the crucible and thermally isolating the crucible from the other individual growth stations. The first and second heater matrices each include at least two legs electrically connected in parallel and each of the legs have at least two resistance heaters electrically connected in series. Each of the individual growth stations have at least one of the resistance heaters within the first heater matrix and at least one of the resistance heaters within the second heater matrix associated therewith. The resistance heaters of the first heater matrix are located above the crucibles and are preferably adapted to provide a homogeneous temperature across tops of the crucibles.
    Type: Grant
    Filed: August 15, 2002
    Date of Patent: May 13, 2003
    Assignee: American Crystal Technologies, Inc.
    Inventors: John D. Schupp, David T. Hearst
  • Publication number: 20030010770
    Abstract: A furnace for growing a high volume of crystals includes a plurality of individual growth stations and first and second heater matrixes. Each individual growth station has a crucible and an insulating container generally surrounding the crucible and thermally isolating the crucible from the other individual growth stations. The first and second heater matrices each include at least two legs electrically connected in parallel and each of the legs have at least two resistance heaters electrically connected in series. Each of the individual growth stations have at least one of the resistance heaters within the first heater matrix and at least one of the resistance heaters within the second heater matrix associated therewith. The resistance heaters of the first heater matrix are located above the crucibles and are preferably adapted to provide a homogeneous temperature across tops of the crucibles.
    Type: Application
    Filed: August 15, 2002
    Publication date: January 16, 2003
    Inventors: John D. Schupp, David T. Hearst
  • Patent number: 4827643
    Abstract: An identification device for a necked container includes a ring-like base structure that is installed about a container neck, and indicia that is carried by the base structure for presenting container data. Preferably the indicia includes presentations of container data that are manually and machine readable. Preferably the indicia is protected from harm by a transparent cover. In one embodiment the identification device has inwardly extending fingers to establish a secure mounting about the neck of the container on which it is mounted. In another embodiment, locking pins are used to establish a secure mounting.
    Type: Grant
    Filed: December 5, 1985
    Date of Patent: May 9, 1989
    Assignee: AGA Gas Central, Inc.
    Inventors: David T. Hearst, Walter M. Schneider