Introduction Of NDT Technology
Airborne and Structure Borne
Ultrasound Leak Survey
What is it?
Ultrasound leak detection covers a wide range of leaks, consisting of pressure leak, vacuum leak, gas leak, steam leak and etc. Ultrasound leak survey detects the turbulent flow produced as the fluid (liquid or gas) moves from the high-pressure side to the low-pressure side of a leak. Ultrasound leak survey is especially beneficial in areas where there is a saturation of gases or where a wide variety of gases, pressurized vessels and vacuum processes exist. For this reason ultrasound leak detection is used in many facilities for safety, environmental, energy or quality assurance programs. Airborne and structure borne ultrasound is an application of heterodyning ultrasonic signal to human audible noise for effective detection of the leak source / location.
How does it works?
During a leak (eg: compressed air), a fluid (liquid or gas) moves from a high pressure to a low pressure. As it passes through the leak site, a turbulent flow is generated. This turbulence has strong ultrasonic components which are heard through headphones and seen as intensity increments on the meter.
A major advantage to ultrasound leak inspection is that ultrasound emissions will be detected and localized at the leak site. Once the leak site is identified, the leak site will tagged immediately, whereas the leak amplitude can be noted and used for reporting and cost analysis.
Furthermore, as fluid moves from a high pressure side of a valve through the seat to the low pressure side, it produces turbulence. This turbulence generates ultrasound which is detected and translated, via heterodyning, down into the audible range. The translated ultrasounds are heard through headphones and seen as intensity increments, usually decibels on a display panel. Ultrasonic tuning allows users to adjust for differences in fluid viscosity (i.e. water vs. steam) and reduce any interference from stray pipe noises. Ultrasound spectral analysis provides an "image" of sound to help determine fluid flow characteristics. Using the time series screen it is possible to determine low, medium or high flow conditions.