| 摘要 |
PURPOSE:To prevent the heater from being directly exposed to an exhaust gas emitted from a heating chamber and to further prevent the heater coat from peeling off and falling down due to cracks by so constituting the heater that all the surfaces of the heater are covered with the heater coat made up of a material prepared by mixing metal oxide ceramics and a fibrous heat-resisting insulation material with each other and uniformly kneading them together. CONSTITUTION:Since fibers such as asbestos are mixed in a heater coat 20, even if there is an irregularity in the thickness of the applied heater coat 20, local stress concentration is generated due to a thermal expansion of the heater coat 20. Even if cracks are produced, fibers of asbestos carry out the mutual connection of cracked portions. Hence, the heater coat 20 is not peeled off and does not fall down, and the wire material of the heater 19 is not exposed. For this reason, particles of organic matters such as steam, oil smoke, seasoning and the like, and particles of the organic matters such as dusts and the like, do not adhere to the heater 19 and also do not generate oxidation corrosion of the heater. Further, no short-circuiting between the windings of the heater 19 occurs and the local extraordinary heat generation of the heater 19 is not caused. |
