| 摘要 |
PURPOSE:To improve explosion preventiveness and noise resistance of a frame rod type flame detector and also to assure its fail-safe. CONSTITUTION:When a flame is present between electrodes A and B, while alternating signals are applied between the electrodes A and B through a transformer T1, the direction of an alternating current Iu, flowing in the parallel circuit of the inter-electrode conduction path caused by the flame and the first resistor R1, decides the resistance of the parallel circuit, and as a result, even harmonics are generated in the alternating current Iu. By extracting the even harmonics included in the alternating current Iu, through an output transformer T2 and a filter circuit 3, a flame detection output is generated. |
