Safety device for oil burner

A safety device for an oil burner comprising:

• a first flame electrode arranged at a position to be exposed to flame formed due to normal combustin in said oil burner;
• means for applying an AC voltage between said first flame electrode and said oil burner so that normal combustion in said oil burner may be detected when a DC flame current flows through said first flame electrode due to the rectification of flame carried out between said first flame electrode and said oil burner;
• a second flame electrode arranged at a position to which flame of said normal combustion in said oil burner does not reach, said means for applying an AC voltae including circuit means for providing a single source of current to said first and second electrodes and dividing current from said single source between said first and second flame electrodes when said second electrode is reached by an excessive flame;
• detection means for detecting abnormal combustion due to either a failure in the flowing of said flame current through said first flame electrode when said flame is too small, or a decrease in said flame current flowing through said first flame electrode because of said division of current between said first and second flame electrodes when said flame is excessive.