By Yossi Tuchner, vibration specialist certified to
ISO 18436 CAT III
Abstract
Ultrasound instruments, whether airborne or structure-borne, provide opportunities to reduce energy waste and
improve equipment availability by detecting developing faults and enabling timely maintenance. Because they respond
to friction, electrical ionization and turbulent flow noise, they help identify insufficient bearing lubrication,
compressed-gas leaks, electrical arcing and loose connections, steam trap failures, flow anomalies and cavitation
in pumps, and more.
Ultrasound Technology Basics
These instruments detect high-frequency acoustic energy generated by operating machinery, electrical discharges and
leaks. Typical working bands are roughly 20 to 100 kHz, above human hearing. Electronics then translate the signal
into the audible range using heterodyning, and levels are displayed in dB or similar units. Modern devices
can store data for software analysis, trending and, in some models, spectral analysis of the ultrasonic content to
identify characteristic frequencies and sources.
How Signals Are Received
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Airborne: microphones or scanning modules detect sound that propagates through air,
such as compressed-air leaks or electrical emissions.
-
Structure-borne: contact probes detect ultrasound conducted through solids,
such as bearing noise, valve issues and steam-trap performance.
Why Ultrasound Is Easy to Pinpoint
High-frequency waves have short wavelengths, so they are more directional and focused. This helps differentiate the
target signal from surrounding plant noise and allows technicians to trace the sound back to its source, even from
a distance. As mechanical faults develop, the ultrasonic component typically increases early, which makes ultrasound
a powerful early-warning tool.
Key Advantages
- Directional response that is easy to trace to a specific source in air.
- Focused, localized signals that are simple to distinguish from background noise.
- Early detection of developing mechanical faults, enabling timely intervention.
- Effective in noisy industrial environments because the instrument filters out most audible-range noise.
- Flexible: complements a broader condition-monitoring program or serves as a stand-alone platform to boost reliability and cut energy losses.
- Active testing possible: transmit ultrasound and verify integrity without pressurizing a vessel, or test cleanroom sealing.
Common Applications
- Locate and quantify compressed-gas leaks in piping and distribution networks.
- Assess steam trap condition and identify blow-through or failed closed traps.
- Monitor rotating equipment condition by listening for friction and bearing defects.
- Implement precision bearing lubrication based on ultrasonic response.
- Detect electrical arcing, tracking and corona, and identify loose electrical connections.
- Perform leak tests on pressure vessels without applying pressure.
- Identify blocked tubes in heat exchangers.
- Detect leakage and seepage from storage tanks.
- Verify cleanroom envelope integrity.
Conclusion
Ultrasound has evolved from simple “find and fix” into a diagnostic and trending technology that can also quantify
energy losses for ROI calculations. Plants use it to lower compressed-air and gas waste, detect electrical risks,
optimize bearing lubrication and enhance condition monitoring of rotating equipment. The result is reduced energy
cost, higher reliability and a stronger predictive maintenance program.