High-frequency electric furnace
Patent 4142063 Issued on February 27, 1979. Estimated Expiration Date: 
March 23, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 23, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3696223 3860737 Production of beta-alumina ceramic articles and furnace therefor Patent #: 4070542 InventorsAssigneeApplicationNo. 05/889306 filed on 03/23/1978US Classes:373/140, With internal atmosphere control (e.g., pressure, vacuum, etc.)219/629, By tube (i.e., pipe)373/157Conducting (e.g., graphite)ExaminersPrimary: Envall, Roy N. Jr.Attorney, Agent or FirmInternational ClassesH05B 6/02 (20060101)C03B 37/02 (20060101) C03B 37/029 (20060101) F27D 11/06 (20060101) F27D 11/00 (20060101) Foreign Application Priority Data1977-03-29 FRAbstractThe invention relates to a high-frequency furnace whose wall is formed by superposed wall-forming members. This furnace includes in particular an inner tubular wall comprising a zirconia tube (38), an alumina washer (39) laid on the zirconia tube and a silica tube (40) laid on the washer. There is a large groove (41) in a top plate (37) to accommodate the silica tube (40). The furnace also includes an outer tube (36) of silica. This structure makes it possible to accommodate differential expansion of the zirconia and the silica in two separate steps. The axial difference is accommodated at the groove (41) while the radial difference is accomodated at the washer (39). Leakage of inert gas pumped into the chamber during operation can then be maintained within acceptable limits throughout the temperature range. Application to the production of optical fibers. | |
