| 摘要 |
PURPOSE:To improve the boiler tube leakage detection in sensitivity by connecting sound sensors directly to the heating thin tubes or the furnace water-cooled wall of a boiler. CONSTITUTION:A plurality of sound sensors 3 are secured directly to heating thin tubes 1a, 1b... or a furnace water-cooled wall 7 which is made of the same material as said heating thin tubes 1a, 1b... and which is unitary with them. Thereby, when tube leakage occurs, the leaking noise generated when steam is blown off through the part of the heating thin tubes 1a, 1b... is transmitted through the metal structure to reach the sound sensor 3 installed nearby, amplified in an amplifier 8 and inputted to a filter circuit 9, where the signal within the acoustic frequency band which is peculiar to the leaking noise is selected, converted into a DC level in a square-law detector 10 and inputted to an alarm setting means 11 which decides it as leakage when the inputted signal level exceeds a preset level and actuates an alarm 12. Accordingly, the noise discrimination ratio and consequently the tube leakage detecting sensitivity are improved. |
