Acoustic Systems Inc
With over 20 years of worldwide applications, Acoustic Systems Incorporated (ASI) ALDS has proven to be the most effective, true real-time, online leak detection method.
Acoustic Systems Incorporated has improved leak detection technology from many years of field proven applications. It provides the quickest leak detection, high sensitivity, precise leak location accuracy and low false alarm rate with minimum maintenance requirement. These improvements were made by developing and applying advanced data processing techniques, such as differential filtering, moving average filtering, proprietary “SMART DRIVE” for adaptive dynamic threshold adjustment, as well as various repetitive filters.
One of these developments, the patented Acoustic Fingerprint Matching Filter, is especially effective. The real-time signal is continuously compared against signature leak profiles (acoustic fingerprint) for the particular operating and geometry conditions. These profiles were developed from a database established from over 20 years of experimental and field leak tests on different pipelines with various fluids. This technique not only drastically reduces the false alarm rate (one alarm a year or less), but also drastically improves the sensitivity and leak location accuracy.
The WaveAlert ALDS is the only leak detection system used not only for pipeline monitoring but also for automatic shut-in of control valve in case of leak. This system will also detect leaks with shut-in flow (zero flowrate in the pipeline). Since this system does NOT depend on flowrate measurement to detect leaks, it will actually detect leaks with higher sensitivity in case of shut-in flow where background noise is much smaller than the one with flow.
The WaveAlert® VIII ALDS is designed to detect the occurrence and location of leaks in gas, liquid, and two-phase flow pipelines. In the instant of a breakdown of the pressure boundary (leak), the release of the elastic force couples with the system fluid to create a transient acoustic wave. This acoustic expansion wave travels outward in all directions from the source at the speed of sound for that fluid. In a pipeline, the expansion waves are guided through the fluid by the walls of the pipe in either direction from the source of the break, to be detected by sensitive acoustic sensors situated at the ends of the pipeline and intermediate valve sites. From the times of arrivals of expansion waves at different sensor locations, the location of the leak is determined. With the use of GPS (Global Positioning System) receivers, the leak detection and clock synchronization functions are performed at each local processor. The ALDS system will continue to detect leak in case of communication fault or loss of communication. After resumption of communications, the leak event and detecting time from the local processors will be used for leak location calculation by the central processor.