| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an electric heater capable of exerting a maximum heat generating capacity of its resistive heating element and capable of being stably used for a long period of time by preventing the breakage of lead wires and damage to protecting tubes. <P>SOLUTION: The electric heater is composed of cylindrical protecting tubes 12 made of ceramic, resistive heating elements 14 spirally wound and inserted into the protective tubes 12, and an insulating layer 16 with a castable material 16a poured into the tube 12 to be solidified to seal the inside of the tube 12. In such a structure, an insulation property of the resistive heating element can be secured, and at the same time, damage to the protecting tube caused by to a heat shock can be prevented. Thus, the durability of the electric heater can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
