PURPOSE: To enable to surely detect the power supply in a waterless condition by a structure wherein a metallic shield plate with good heat conductivity is provided outside the bottom surface of a vessel, which is transparent and has poor heat conductivity such as glass or the like, employed in the electric water heater.
CONSTITUTION: The fitting cylinder 6a of a submerged type heating element 6 is fitted through a waterproof packing 8 into a through hole 7 provided at the bottom surface of the transparent bottomed vessel 1 made of heat resisting glass. The shield plate with good heat conductivity such as tin plate or the like, a rubber bottom plate 10, a holder 11, a wave washer 12 and a plain washer 13 are inserted onto the fitting cylinder 6 in order and fixed by fitting a push nut 14 onto the cylinder 6. A thermal fuse 15 is fitted on said holder 11 in such a manner that its plane part is urged against the shield plate 9 by means of a spring 16. In the structure as described above, when no-water heating happens, the shield plate 9 is abruptly heated due to the radiation heat of the heating element 6, resulting in enabling to surely actuate the thermal fuse 15.
OKADA KATSUROU
MURAKAMI YOSHIKAZU
