What types of leaks and loss of tightness can be detected using ultrasound?

Ultrasound can be used to detect leaks in systems where gases escape or are drawn in due to a pressure difference. Turbulent flow occurs at the leak and generates sound in the ultrasonic frequency range.

Typical applications include:

• leaks in compressed air systems,
• leaks in gas lines and gas-carrying systems,
• leaks in vacuum systems,
• leaks in steam and utility systems.

The ultrasonic signals generated by the leak can be detected and located using an airborne sound sensor or an acoustic camera.

Non-pressurized components can also be tested for loss of tightness. For this purpose, an ultrasonic transmitter is placed inside the test object. If the generated ultrasonic signal escapes through a leak, it can be located from the outside.

This method is suitable, for example, for:

• doors and windows,
• cabins and vehicle bodies,
• containers,
• hatches,
• enclosed components and housings.

Reliable detection of a leak depends on several factors, including:

• the pressure difference between the system and its surroundings,
• the size and shape of the leak,
• the type of gas escaping,
• the measurement distance and orientation of the testing device,
• background noise,
• the sensor or testing device used.

Locating a leak must be distinguished from quantitatively assessing it. Not every detected leak can automatically be expressed as a volumetric flow rate or financial loss. A quantitative loss estimate is only possible when the applied method and the required operating conditions are suitable.