Leak detection in compressed air network
Since air leaks are almost impossible to see, special methods must be used to locate them. The best way to detect leaks is to use an ultrasonic acoustic detector, which can recognize the high frequency hissing sounds associated with air leaks. These portable units consist of directional microphones, amplifiers, and audio filters, and usually have either visual indicators or earphones to detect leaks.
Ultrasonic leak detection is probably the most versatile form of leak detection. Due to its capabilities, it readily adapts to a variety of leak detection situations. The principle behind ultrasonic leak detection is simple. In a pressure or vacuum leak, the leak flows from a high pressure laminar flow to a low pressure turbulence. The turbulence generates a white noise which contains a broad spectrum of sound ranging from audible to inaudible frequencies.
An ultrasonic sensor focuses in on the ultrasonic elements in the noise. Since ultrasound is a short wave signal, the sound level will be loudest at the leak site. Ultrasonic detectors are generally unaffected by background noises in the audible range because these signals are filtered out.
This means leaks can be heard in even the noisiest environments. The advantages of ultrasonic leak detection include versatility, speed, ease of use, the ability to perform tests while equipment is running, and the ability to find a wide variety of leaks. These test require a minimum operator training, and it takes them hardly 15 minutes to be familiar with the test. Due to the nature of ultrasound, it is directional in transmission.
For this reason, the signal is loudest at its source. By scanning around the general direction of the test area, it is possible to quickly zero in on a leak site and pin point its location. For this reason, ultrasonic leak detection is not only fast, it is also very accurate.