What is ultrasonic testing, and how is it used in preventive maintenance?

Ultrasonic testing detects high-frequency sound signals that are generated by various processes in machines and industrial systems. Many of these signals are above the human hearing range and cannot be heard or evaluated without suitable testing equipment.

Ultrasound can be generated, for example:

• at leaks in compressed air, gas, and vacuum systems,
• by friction or damage in bearings,
• by insufficient or excessive lubrication,
• by cavitation in pumps and compressors,
• during the operation of steam traps and valves, and
• by electrical partial discharges and insulation defects.

Ultrasonic testing devices detect these signals and make them audible and/or visible. This allows changes to be identified at an early stage, defects to be located precisely, and maintenance activities to be planned more effectively.

Ultrasonic testing can often be performed while the system is operating and without interfering with the process. It is therefore well suited for condition-based and preventive maintenance.