| 摘要 |
PURPOSE:To perform accurate detection of oxygen densities corresponding to various kinds of burners by a method wherein an ion current which is almost stabilized after the formation of a flame in each of the burners is stored and is compared with a constantly supplied ion current and the density of oxygen included in combustion air is detected in accordance with the difference between the stored ion current and the constantly supplied ion current. CONSTITUTION:When a heater is ignited, a flame is generated on a burner head 1 and an ion current flows from the burner head 1 to a from rod 2. Such ion current is converted into a voltage signal A through a resistor 5 and the signal A is further converted into a voltage signal B through a protective resistor 6 which signal B is then applied on a microcomputor (muCOM) 9. The microcomputor 9 stores an ion current flowing after a predetermined time interval (that is, after a lapse of a predetermined time in which the ion current is stabilized) and the stored ion current and the ion current flowing from the burner head 1 to the frame rod 2 are compared with each other. Thus, when it is detected that the difference between the above two ion currents has reached a predetermined value, a signal D is generated from the microcomputor 9 to thereby alarm that the heater is short of oxygen. |
