MRO Magazine

Not Just New – Better

Seeing sound with astounding accuracy is the future of leak detection in compressed air systems. Acoustic imaging includes ground-breaking technology that uses an array of tiny supersensitive microphones to detect sounds both in the human hearing and ultrasonic ranges.


Engineering

June 8, 2020
By Javier Irazola

Air leaks will occur, but today there is a more comprehensive method for finding them. The simplicity of the acoustic imager means anyone can use it. No more soapy water or hearing accessories necessary. Acoustic imagers are a practical and profitable method for facilities, allowing air leak detection to be added to regular preventive maintenance routines.

For production facilities that have started using the acoustic imager, early results validate energy savings. One customer saw a nearly 26 per cent recovery in compressed air capacity and close to $49,000 in annual electrical energy savings—based on their total installed capacity of air compressors equalling 330 horsepower. Before using the sonic imager to inspect for air leaks, the plant ran four compressors close to full capacity. After a oneday inspection, they found and repaired more than 130 leaks.

Now the facility can handle most of its compressed air needs with just three compressors. Since they were expanding the plant at the time, the fourth compressor will not go to waste and will save the company a capital expense.

Leak detection tips and tricks
In one day, you can scan your entire system to identify all the leaks in it. But then what? You might not have the resources on hand to repair all those leaks. The acoustic imager includes software that helps to identify where leaks are within the system, and allows for on-screen annotation, leak size estimation (about how big is that leak?), and smooth report development.
• Asset tagging lets others know where the leak was found;
• On-screen annotation provides additional context and considerations for others; and,
• Leak analysis approximates the size of the leak to help you prioritize which leaks deserve attention first.

Before you can repair leaks, you must find them—and that can be difficult in even the quietest environments. Large manufacturing plants may have compressor systems that stretch from one end of the facility to the other, passing through and around other operating systems. From the compressor to the air dryer, main line to equipment lines, and equipment—leaks can be hidden anywhere.

The most common places to find air leaks are couplings, hoses, fittings, pipe joints, quick disconnects, condensate traps, and valves. That is a lot to inspect, and much of it is hard to reach. While maintenance team members do their best to fix leaks they find during normal maintenance routines, most facilities don’t have the resources to dedicate specifically to this task. Technicians might make more of an effort to identify where a leak is located if pneumatic tools were not working properly, but even then it is a trivial task.

Seven steps to mitigating air leaks
Make the task of detecting air leaks easier, more comprehensive, and more accurate with these seven steps.

Step 1: Visualize the system; an acoustic imager can visually scan large areas from more than 10 metres away in heavy noise conditions. Scanning from a distance keeps technicians safe around running equipment, and makes finding leaks in hard-to-reach areas possible.

Step 2: Follow the path of the system scanning for leaks. An array of ultra-sensitive microphones expands the field of view so maintenance teams can quickly and accurately locate air, gas, and vacuum leaks in compressed air systems.

Step 3: Isolate the sound frequency of the leak to filter out loud background noise. You will see where the leaks are and be able to estimate their size, which is based on your distance from the leak and its decibel level.

Step 4: Capture and identify leaks for comprehensive reporting. This includes asset tagging and on-screen annotation.

Step 5: Create a comprehensive report, including leak images, asset tags, annotation, estimated leak size, and more—such as how much those leaks will cost if you don’t fix them.

Step 6: Use the report in your workflow management to ensure repairs are completed on high-priority leaks first and all leak repairs are documented.

Step 7: Confirm the repair using the acoustic imager.

Air leaks and the future
Part of the reason air leaks are a big issue is because they are hard to find. Even when found and fixed, new leaks keep popping up—a fact of life due to the wear and tear on equipment over time. Since it can be difficult to find air leaks, most facilities just accept them as a cost of doing business. While it may not be possible to eliminate all leaks, it is possible to substantially reduce their number. That is where an acoustic imager provides its greatest value, and where the future of leak detection is headed. MRO

Javier Irazola is Global Product Manager for the Industrial Imaging group at Fluke Corp. He is leading the launch of acoustic imaging solutions. He has eight years of previous experience in engineering and project management for utility projects in the USA and EU, and three years working for the product innovation department of Fluke Industrial Group.