Neptune Acoustic Leak Detection
Ultrasonic leak detection is a method of pipeline leak detection that uses a directional hydrophone that ‘listens’ for ultrasounds generated by leaking fluids passing through an orifice under pressure. The acoustic signals generated by a leak tend to be at frequencies above 30kHz. The software uses techniques that determine the difference between leak generated sound and lower frequency noise such as that caused by the attendant ROV and surface vessels.
Hydrophones are effectively underwater microphones that ‘listen’ for ultrasound generated by leaking fluids under pressure. For small leaks, the acoustic signals generated tend to be at frequencies well above the audible range thus requiring sophisticated sensors and software to reliably determine the difference between ‘leak’ generated sounds and ambient sounds. The major problems with this method are the sounds caused by the attendant (ROV) and other vessels in the vicinity. However, modern data handling and spectral analysis techniques have improved the method sufficiently such that the method can be highly successful.
Neptune Oceanographics’ acoustic leak detection sensor may be diver-held or mounted on a ROV, AUV, or PIG. It incorporates a directional hydrophone with the system featuring noise filters to remove the effects of ambient noise, including mechanical noise from an ROV or support vessel.
The detected acoustic signals are sent, via the ROV umbilical or diver cable, to the on-board PC where acoustic intensity may be displayed either alongside fluorometer readings in dual capacity mode or as a single channel. In common with the fluorometer system, the sensitivity is controlled by the data logger to obtain the maximum dynamic range.
- Hydrophone can be diver held, ROV or AUV mounted
- Directional hydrophones listening ‘cone’ approx. +/-12 degrees
- The system is quickly mobilised for offshore operations worldwide
- Graphical display and data logging
- Operating depth to 1,200m
- Compatible with Neptune’s two channel leak detection system to allow simultaneous operation with other leak detection sensor types