| 摘要 |
<p>A plate heater configured in such a manner that thermal stress and thermal strain due to a temperature change during heating-cooling are less likely to occur, the sheath of a sheath heater is less likely to be melted and broken during welding, and a blowhole is less likely to be formed in a weld portion. A plate heater is formed in such a manner that a sheath heater (3) is embedded in a groove (11) formed in a heating plate (1), the depth of embedding of the sheath heater (3) is set to be 3/4 to 5/6 of the diameter of the sheath heater (3), and the heating plate (1) and the sheath (13) of the sheath heater (3) are welded together by a filler (16) filled into the gap between the groove (11) and the sheath heater (3). Chamfers (c) are provided along the opening edges of the groove (11) of the heating plate (1). The thickness (t) of the sheath (13) is two or more times as large as the depth of weld penetration in the sheath (13) by welding.</p> |
