Leak Detection of Pipe Line by an Optical Fiber Ae Sensing System

Fast and accurate detection of gas and/or liquid leakage is very important for safe operation of process plant and social infrastructures. Study aims to develop a reliable detection system of minute leakage of gas and/or liquid from pipes. We used an optical fiber Mach-Zender and Michelson type laser interferometer as an acoustic emission (AE) monitoring system. The system utilizes polymer coated telecommunication and metal coated optical fiber as AE sensor depending on the pipe temperature. Sensitivity of the system was significantly improved by multi-winding of the sensing fiber on the pipe and enables the monitoring of weak cylinder wave beyond the union and elbows. Leak location can be estimated from single AE signal using the propagation velocities of Land F-mode waves and the wavelet transform. Paper introduces how weak leakage of gas and/or fluid were monitored by an advanced optical fiber AE monitoring system. Emphasis of this paper is laid on an appropriate utilization of complex cylinder wave with dispersive nature.