| 摘要 |
<p>PURPOSE:To improve the mechanical strength and the reliability against a snapping of a heater, by forming the primary winding in setting the diameter of a molybdenum mandrel in the range from 4.3-6.0 times the diameter of a tungsten filament. CONSTITUTION:The diameter of a molybdenum mandrel 3 is set in the range from 4.3-6.0 times the diameter d of a tungsten filament 2, the primary winding 4 in a coil form is formed, and then the secondary winding is composed to make up a heater 1. In such a formation, a winding distortion resulting from a compressing stress in the curl inward direction and a tensile stress in the curl outward direction of the tungsten filament 2 when it is wound on the molybdenum mandrel 3 are relaxed broadly, the mechanical strength of the primary winding 4 is improved, and a snapping of the heater 1 can be prevented.</p> |
