| 摘要 |
PURPOSE:To maintain a consistent burning state even during the operation of a fan, by providing a pressure sensor adapted to detect the blockage of exhausting combustion gas due to a reverse wind and turn a fan into a high speed operation. CONSTITUTION:A fan 10 runs at a slow speed while a burner 4 burns a small quantity of fuel. As the fan 10 provides only a small delivery pressure, the exhaust of combustion gas is blocked to increase the internal pressure of body 1 upon the actuation of fan. Upon the body 1 having its internal pressure raised in excess of an external pressure, the diaphragm 13 of pressure sensor 12 is urged downwardly against a spring 18 to lower an operating lever 19 jointly. The lowering movement of operating lever 19 causes a micro-switch 20 to close its contact and a controller 21 to turn the fan 10 into a high speed operation. The exhausting force of combustion gas is thus increased. Upon the combustion gas being properly exhausted and the body restoring its internal pressure to normal value, the fan 10 resumes its normal operation. |
