| 摘要 |
PURPOSE:To surely detect, without error, a reduction of oxygen concentration when the burning rate is small by automatically modulating the burning rate to increase the flame ionic current at a moment when the flame ionic current drops to a level which is higher than a predetermined level by a certain amount. CONSTITUTION:The flame ionic current is measured to determine detection levels C, D of the ionic current of flame whose reduction of oxygen concentration is to be detected. When the oxygen concentration is reduced, the flame ionic current is also reduced. When it is reduced to the level D, the burning rate is increased and the flame ionic current is also increased. As the oxygen concentration is reduced, the flame ionic current is reduced, and when it is reduced to the level C, the burning is stopped and a warning lamp is illuminated. |
