US Patent 7372002 Fluid heating device and cleaning device using the same

A washing water inlet for receiving washing water is provided on an upper surface at one end of a case main body in a fluid heating device, and a washing water outlet for feeding heated washing water to a pump is provided on an upper surface at the other end of the case main body. A linear sheathed heater is arranged so as to penetrate the case main body. A spring is spirally wound around an outer peripheral surface of the sheathed heater. An outer peripheral surface of the sheathed heater, the spring, and an inner peripheral surface of the case main body form a flow path. The flow path is formed in a spiral shape with the length of the case main body used as its axis.