| 摘要 |
PURPOSE:To automatically detect stains within a heat exchange passage due to adherence of scale by catching a change in the electrostatic capacitance value between plates by a variation of the frequency of an oscillation circuit when there is no hot water in the heat exchange passage, and providing stain surveilance means informating the existence of stains of the heat exchange passage to the outsides. CONSTITUTION:In the interior of a bath boiler 3, an electrode 5 for detecting electrostatic capacitance and a water level sensor 6 such as pressure switch of the like are incorporated between a heat exchange part 4 and a circulation pipe 2. The electrode 5 for detecting electrostatic capacitance is formed by coating a pair of conductive plates 7 with a syntheric resin 8 a an insulation protection. An oscillation circuit (R' 10R) 9 is formed by the electrostatic capacitance C detected by the electrode 5 for detecting the electrostatic capacitance and a reference resistor R. Signals from the oscillation circuit 9 and the water level sensor 6 are input the bath boiler 3, and stain surveilance means 11 informing the degree of stains of the heat exchange passage connecting the circulation pipe 2 and the heat exchange part 4 to a bath boiler controller 10 to which the action control of the bath boiler 3 is inputted, is provided in the bath furnace 3. |
