Here You Go.


Ultrasound - Are You Listening to Your Plant Floor Equipment?


2020-05-Ultrasound for the plant floor--1We've all heard of ultrasound being used at the doctor's office, but can you use it to monitor and troublshoot your plant floor equipment?

The answer is a resounding Yes. In fact, no predictive maintenance program should be without ultrasonic capabilities.

How Does Ultrasound Testing Work?

The term ultrasound describes sound waves that are high frequency and beyond the range of human hearing. Ultrasound equipment detects sounds within these ranges and allows you to tune out other sounds that you aren't interested in. Because sound is directional, ultrasound also allows you to pinpoint where the sound is coming from.

As you get closer to the source of a particular sound, the intensity (measured in dB) increases. The output can be a plot showing how the intensity of sound varies over different frequencies. Ultrasound testing equipment can also modify the sound so that it is something you can learn to recognize through a pair of headphones. For example, an open valve has a rushing sound.

What Makes Ultrasound Testing Different

Ultrasound has certain key benefits compared to more traditional testing methods:

  • It is very versatile
  • It is straightforward to learn and use
  • It is non-contact
  • It can performed while the system is online
  • It can pinpoint the location of problems
  • It is quick and effective

What Can I Use Ultrasound For?

Let's talk about four specific ways you can use ultrasound in your facility: leak detection, steam trap and valve inspection, bearing inspection and lubrication, and electrical inspection.

Leak Detection

The more traditional method of leak detection is a combination of compressed air and soapy water. While many facilities still use this approach, there are some major problems with it that include safety. An alternate approach is the use of ultrasound.

When gases leak, they create a turbulent flow that generates sounds that your ultrasonic equipment can detect. Once you detect the sound of a leak, you can use the intensity and directionality of the sound to track down the source -- even in a noisy environment.

Note that you can also use ultrasound technology to run compressed air leak surveys. These surveys allow you to locate and report on cost estimation per leak as well as provide information about your carbon footprint.

Steam Trap and Valve Inspection

Ultrasound can also be used to inspect stream traps and valves. Both steam trap and valve operation can be investigated in just about any environment. For a valve, it is as simple as determining whether you are picking up the sound of turbulent flow. When you consider how many stream traps and individual valves there are in your plant floor, it makes sense that a quick, efficient means of inspection is important.

Bearing Inspection and Lubrication

When bearings are about to fail of are under/over lubricated, they emit a sound profile detectable by ultrasound. The sound correlates to the amount of friction involved. A bearing that is not functioning properly will generate a different sound profile from one with no issues. The ability to use ultrasound allows you to step in and take care of the problem before it develops any further.

In fact, you can set up automatic ultrasound monitoring of the bearings on your machines to other systems. Another benefit of using ultrasound with you bearings is how it allows you to judge the right amount of lubrication needed.

Electrical Inspection

Electrical issues have sounds associated with them, too. Ultrasound can pick up on ...

  • Partial discharge or tracking
  • Arcing
  • Mechanical vibrations from transformers
  • Corona

These electrical phenomena generate sounds because the ionization involved disturbs the air molecules in the surrounding area. While some electrical equipment produces a steady hum, that is far different from the types of sound associated with such phenomena.

The Role of Ultrasound in Predictive Maintenance

Here are some of the ways that ultrasound testing will contribute to your PdM (predictive maintenance) program:

  • Detection and elimination of costly leaks
  • Monitoring of steam traps, valves, boiler, heat exchangers, and condensers
  • Monitor the condition of bearings
  • Enhance the accuracy and effectiveness of lubrication programs
  • Detect potentially dangerous and always damaging

Because of its versatility and effectiveness, ultrasound has become a must-have tool for PdM. And by contributing to PdM, ultrasound testing also contributes to the reliability and lifespan of the equipment you are tasked with maintaining.


Ultrasonic testing isn't just for medicine -- its for you facility, too. If you aren't already utilizing ultrasonic equipment as part of your PdM on your plant floor, this would be a great time to start.

Author & contact Info: Nolan Crowley: (513) 256-9766 and

Subscribe to the HECO blog




Subscribe to Email Updates

Posts by Topic

see all

Recent Posts