| 摘要 |
The monitoring device uses a sensor positioned in the air or exhaust gas flow path of the gas heater and connected in an electric control circuit, which is responsive to the detected fan feed rate. The sensor is provided by a temperature-dependent resistance (12), connected in a heating circuit with a heating and resistance characteristic selected for providing a resistance variation dependent on the cooling caused by the flow (16), relative to the condition when the fan is not in operation. |
