SHEATH HEATER AND GLOW PLUG

摘要

A sheath heater includes a tubular metallic sheath containing as a main composition nickel or iron, closed on the forward end side and extending in the axial direction, a heat generating coil arranged in the sheath along the axial direction and having the forward end connected electrically with the sheath, a lead member located in the sheath and having the forward end connected electrically with the heat generating coil and the rear end projecting to the rear end side of the sheath, insulating powder filling the periphery of the heat generating coil, in the sheath, and a sealing member for sealing the rear end of the sheath, characterized in that the internal atmosphere of the sheath sealed by the sealing member has a partial pressure of nitrogen higher than the partial pressure of oxygen , and the heat generating coil, including as a main composition iron, contains 5-20 wt.% of chromium, and 8-15 wt.% of aluminum. Such a sheath heater is suitably used in a glow lamp, and the like.