KONTAKTLOES OPVARMNING AF TYNDE FILAMENTER

摘要

An arrangement for contact-free heating of thin filaments comprises means for linear supporting of a length of filament 10, an induction coil 11 set up close to the filament, with the axis of the coil parallel to the length of filament, a source 15 for AC current in the HF and UHF bands connected to the coil and a conductive rod 16 connected to an end winding of the coil 11 and arranged principally parallel to the length of filament. The arrangement is so set up that there is a heating of the filament close to the conductive rod. The filament 20 is taken through a vertical cylindrical chamber 21, in which there is maintained a reducing atmosphere. The coil 11 has a non-constant diameter, with the diameter being greater at the end 14 where the rod 16 is attached, while the opposite end 12 of the coil is connected to earth 13. The rod 16 can be so shaped that the space between the rod and the filament varies over the length of the rod, so that the temperature profile along the heated part of the filament varies. A Class C valve oscillator is used as the AC power source 15 in the induction heater. Such an energy source has [last line illegible]. <IMAGE>