The Advantages of Broadband Ultrasonic Analysis During Leak Detection on Compressed Air Systems

Ultrasonic testing devices have long been established in the field of preventive maintenance to detect leaks on compressed air systems.These devices usually record a frequency range around 40 kHz. SONOTEC Ultraschallsensorik Halle GmbH is breaking new ground with the SONAPHONE ultrasonic testing device. The main difference between this device and the previously available devices is the broadband technology of the sensors in a frequency range from 20 to 100 kHz. This makes applications like automatic leak analysis more reliable. IRISSis Sonotec‘s master distributor of Sonophone in the America‘s.

Leak detection on industrial supply systems for compressed air and technical gases for the purpose of energy saving and plant safety is by far the most common application of ultrasonic technology. This is because compressed air is one of the most expensive energy sources and is responsible for 10% of industrial energy costs. 30% of this expensive energy is lost simply due to leaks in compressed air systems. This makes detecting and eliminating leaks worthwhile.

A significant advantage that the broadband range technology offers is evident even when searching for a leak. Earlier ultrasonic detectors use piezoceramic probes, which are resonant in a very small range around 40 kHz. Because leaks emit broadband ultrasound, they were able to be found with 40 kHz. However, the 40-kHz probes also pick up a great deal of interfering ultrasonic signals. New broadband sensors with incredibly sensitive ultrasonic microphones and high sampling rates improve and simplify leak detection for the user in challenging, loud environments, as the spectrogram of the display on the SONAPHONE immediately informs the user if there is an interfering ultrasound and what frequency it is in. Using the touchscreen, the user can simply move the frequency that they want to hear out of the range of the interfering ultrasound signals, enabling them to detect leaks in challenging environments.

After the leak has been detected, the broadband sensors offer another advantage. They enable the leak not only to be found, but also to be automatically analyzed. To correctly evaluate the leak, you only have to enter the system pressure and the type of gas into the device and start the specially developed leak analysis. With just the touch of a button, the service engineer initiates the measurement and automatic analysis of the leak, and the loss in liters per minute is displayed to them immediately. Additionally, the device will rank the leak in a class from 1 to 5 (1 = small leak, minor loss [green]; 5 = large leak, very high loss [red]). This evaluation process is based on a procedure patented by Sonotec. The extensive documentation of the new SONAPHONE is another advantage alongside the analysis. Upon completion, a full report including photos can be generated and exported.


With the new SONAPHONE and the LeakExpert app, which is specially tailored to leak detection, leaks on compressed air and vacuum systems and gas lines can be detected and automatically analyzed with pinpoint accuracy. The multifunctional device with touchscreen processes the ultrasound signals directly. A report can be generated quickly and easily and used as a decision-making tool for follow-up actions and as proof of successful energy management. With a single click, the documentation of the results is available for management, with comprehensive information about the precise location of the leak, the energy loss, a photographic record and the priority level of the repair. Additionally, by systematizing the search for leaks and their evaluation, the device contributes to significant time and cost savings in maintenance. Error-prone paper records are a thing of the past, since all data can be evaluated and updated directly in the device. This also facilitates the verification of energy saving measures in the context of the documentation obligation for companies that are certified in accordance with EN ISO 50001.

Sonaphone Applications

  • Detection of partial discharges in electrical apparatus
  • Detection and analysis of leaks in compressed air, gas and vacuum systems
  • Steam trap testing
  • Condition monitoring

A Powerful Case for Infrared Windows

A regional Power Generation Facility had been tasked by their insurance carrier to perform regular preventive maintenance on the switchgear within their facility. Unfortunately, regular downtime was not a practical option for them as the processes required to do the live inspections were hazardous and required more manpower and resources than they had to provide. In addition, they too were feeling the pressure of the requirements of NFPA 70E and were starting to re-think their strategy since inspections of energized equipment was becoming more restrictive, more time consuming and more costly

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