| 摘要 |
<p>A sheathed heater comprising at least two core pieces of porcelain insulator separated to each other in the axial direction of said core piece, at least two lead pins separated to each other and inserted into the core pieces axially, at least two internal heater coil segments wound around the at leaat two core pieces, respectively, and a cylindrical metal sheath into which the core pieces and the internal heater coil segments are inserted through a thermal and electrical insulation material, wherein adjacent ends of adjacent internal heater coil segments are electrically connected to the same lead pin, or lead pins of the same electric potential.</p> |
