Stephen Paul Strong

US Patent:

6724803, Apr 20, 2004

Filed:

Apr 4, 2002

Appl. No.:

10/115694

Inventors:

Douglas J. Miller - North Olmsted OH
Werner H. Ruoff - Berea OH
Allan Webster Intermill - Strongsville OH
Thomas R. Thoman - North Ridgeville OH
Richard L. Shao - North Royalton OH
Stephen L. Strong - Livingston TX

Assignee:

UCAR Carbon Company Inc. - Wilmington DE

International Classification:

F27D 706

US Classification:

373140, 373157

Abstract:

An induction furnace capable of operation at temperatures of over 3100Â C. has a cooling assembly ( ), which is selectively mounted to an upper end of the furnace wall ( ). The cooling assembly includes a dome and a lifting mechanism ( ), mounted to the dome, which raises a cap ( ) of the furnace slightly, allowing hot gases from the hot zone to mix with cooler gas in the dome.

US Patent:

6898232, May 24, 2005

Filed:

Mar 3, 2004

Appl. No.:

10/792097

Inventors:

Douglas J. Miller - North Olmsted OH, US
Werner H. Ruoff - Berea OH, US
Allan Webster Intermill - Strongsville OH, US
Stephen L. Strong - Livingston TX, US
Thomas R. Thoman - Ridgeville OH, US
Richard L. Shao - N. Royalton OH, US

Assignee:

UCAR Carbon Company Inc. - Wilmington DE

International Classification:

F27D007/06

US Classification:

373140, 373157

Abstract:

An induction furnace capable of operation at temperatures of over 3100 C. has a cooling assembly (), which is selectively mounted to an upper end of the furnace wall (). The cooling assembly includes a dome (), which is actively cooled by cooling water coils (). During the cool-down portion of a furnace run, cooling initially proceeds naturally, by conduction of heat away from the hot zone through a furnace insulation layer (). Once the temperature within the furnace hot zone () reaches about 1500 C. , a lifting mechanism (), mounted to the dome, raises a cap () of the furnace slightly, allowing hot gases from the hot zone to mix with cooler gas in the dome. This speeds up cooling of the hot zone, reducing cool-down times significantly, without the need for encumbering the furnace itself with valves or other complex cooling mechanisms which have to be replaced periodically. The life of a graphite furnace susceptor () at the high operating temperature is increased by surrounding the susceptor with a barrier layer () of flexible graphite, which inhibits evaporation of the graphite. Additionally, witness disks (), placed within the susceptor, provide an accurate temperature profile of the hot zone.