| 摘要 |
PURPOSE:To obtain a flame current detector, high in safety and excellent in performance, by a method wherein combustion condition is judged by impressing a positive voltage during burning of a burner, the deterioration of insulation of a flame rod is decided by impressing a negative voltage and the abnormality of a detecting circuit is judged by the difference of currents upon impressing negative and positive voltages before combustion. CONSTITUTION:A combustion abnormality judgement unit 33 judges the combustion condition of a burner 17 at present by the outputs of a positive current detector 31 and a negative current detector 32. When a switching circuit 15 is connected to a contact (a) and an electric potential (ed) has become lower than an electric potential (ed1), it is judged that the burner 17 has lost fire and the supply of fuel is stopped. In the case of abnormal combustion, the supply of the fuel is stopped when the output potential (ed) has become higher than an output potential (ed2). When the switching circuit 15 is connected to another contact (b) and the output (ed) has become lower than a threshold value (ed3), it is decided that the insulation of a flame rod 16 is deteriorated. When an abnormality is generated, a signal is outputted to a reset unit 34 to stop the operation of a pump driving unit 22 and stop the combustion of the burner 17. The output of the circuit 15 when it is connected to the contact (a) or the contact (b) is measured before the ignition of the burner 17 and the difference of outputs is operated by an operating unit 35 whereby an initial abnormality judgement unit 36 decides an abnormality. |
