By Ron Marshall
Imagine if you were 30 feet tall — all the things you could accomplish in your plant! Well, one newly developed style of leak detector can greatly extend your leak detection range. One such detector was recently put to the test in a large industrial site with amazing results.
One of the best ways to save compressed air costs is to look for ways to reduce leakage flow. Reducing the flow in a well-controlled compressed air system results in a reduction of compressor energy consumption and often reduces pressure loss, saving even more.
A common way to find leaks is using the human ear. In quiet facilities, if all the audible leaks are fixed, this exercise usually results in significant energy savings. But unfortunately, most industrial sites are very noisy, drowning out any hint of audible compressed air waste. To be able to better detect gas leakage, there are many ultrasonic devices now available to amplify the telltale high frequency emitted by gas leaks.
Typical ultrasonic devices are a hand-held style that look like handguns. The trigger is pulled, enabling a directional microphone mounted on the front of the unit to connect with operator worn earphones. The detector is directed in a sweeping motion towards various areas of the plant and leaks are found by observing the change in amplified signal. The signal change and the waving motion will lead the operator in one direction or another, enabling them to find even the tiniest of leaks of a fraction of a cubic foot.
This type of directional detection is highly effective if you have good access to the leak location. Typically, when a leak is found, the operator must feel around for the air leak to detect the exact location on the component. This is problematic when the leak is, for example, near the roofline of a large industrial building some 30 or 40 feet up.
Recently, there have been huge advances in leak detection. Sophisticated visual acoustic imagers have now been developed that overlay a digital picture of a sound pattern onto a video screen image taken with a video camera. This allows the operator to quickly pinpoint exact leak locations. This type of detector can be extremely useful where common leakage points are not normally accessible, such as for piping run along the ceiling, or where pneumatic components are installed behind safety shields.
You should be aware that ultrasonic leak detectors can find leaks not only in compressed air systems, but other systems like industrial gasses, vacuum, and steam. Many are also useful in detecting electric discharge cause by failing high voltage electrical insulators.
Recently, during a leakage audit at a large highway bus manufacturer, a leak in the Argon piping was detected at ceiling levels above an entrance door. The estimated leakage flow, automatically calculated by the detector using the distance and sound level, was estimated at only one cubic feet per minute. But because the cost of Argon is about 230 times more than compressed air, and the leak flow was continuous, the leak calculated to $24,000 per year in wasted gas.
There were similar valuable finds, done in about two hours of scanning. In all, the facility was found to have numerous leaks in their Argon, CO2, Nitrogen and compressed air systems totaling about $72,000 in annual cost. It sure pays to detect and correct gas leaks!