|Smart Water Monitoring platforms are generally ultra-low-power sensor nodes designed for use in rugged environments and deployment in hard-to-access locations to detect changes and potential risk to public health or environmental damage in real-time. Examples include extreme pH or low DO values signal chemical spills due to sewage treatment plant or supply pipe problems.
Internally based systems utilize field instrumentation (e.g. for flow, pressure and fluid temperature) to monitor internal pipeline parameters; these pipeline parameters are subsequently used for inferring a leak. System cost and complexity of internally based LDS are moderate because they use existing field instrumentation. This kind of LDS is used for standard safety requirements.
A leak changes the hydraulics of the pipeline, and therefore, changes the pressure or flow readings after some time. Local monitoring of pressure or flow at only one point can, therefore, provide simple leak detection. As it is done locally it requires in principle no telemetry. It is only useful in steady-state conditions, however, and its ability to deal with gas pipelines is limited.
Acoustic Pressure Waves:
The acoustic pressure wave method analyses the rarefaction waves produced when a leak occurs. When a pipeline wall breakdown occurs, fluid or gas escapes in the form of a high-velocity jet. This produces negative pressure waves which propagate in both directions within the pipeline and can be detected and analyzed. The operating principles of the method are based on the very important characteristic of pressure waves to travel over long distances at the speed of sound guided by the pipeline walls. The amplitude of a pressure wave increases with the leak size. A complex mathematical algorithm analyzes data from pressure sensors and is able in a matter of seconds to point to the location of the leakage with accuracy less than 50 m (164 ft). Experimental data has shown the method's ability to detect leaks less than 3mm (0.1 inches) in diameter and operate with the lowest false alarm rate in the industry – less than 1 false alarm per year.
However, the method is unable to detect an ongoing leak after the initial event: after the pipeline wall breakdown (or rupture), the initial pressure waves subside and no subsequent pressure waves are generated. Therefore, if the system fails to detect the leak (for instance, because the pressure waves were masked by transient pressure waves caused by an operational event such as a change in pumping pressure or valve switching), the system will not detect the ongoing leak.
Benefits: Protecting the environment, avoiding harming individuals, avoid legal trouble
-Health & Safety/Litigation Safeguard
Key vendors: Alerton, Libelium, Poly Processing