| 摘要 |
A key parameter in the safe operation of a burner system is the signal provided by the flame sensor used to assure that flame is present when fuel is flowing to the system's combustion chamber. Once steady state operation of the burner system is established in either standby phase or a non-standby phase, the flame sensor's signal level is normally at a substantial displacement from the threshold level which determines whether flame is judged to be present or not. On occasion flame sensor operation may deteriorate, the sensor may become misaligned, or application conditions may change, any of which may result in a flame signal level during steady state operation which is closer to the threshold level than expected. The function of this invention is to periodically test for and detect such an out of range signal level from the flame sensor. When the system is in standby operation and no flame is present, the invention involves checking whether the flame signal level is within a range defined by a low margin level and the threshold level. When the system is in an operational phase where flame is expected, the invention involves checking whether the flame signal level is within a range defined by a high margin level and the threshold level. Should either check detect such an unsatisfactory condition, a signal is provided indicating this abnormal condition. Preferably, the abnormal condition is used to control the flashing of an indicator light, fast during standby phase if the flame signal level is too close to the threshold level and more slowly if the flame signal level is too close to the threshold level while flame is present. It is also possible to use two different lights for the indicators. |
