Air leaks can form in many places in a compressed air system. Some are obvious, but others are well hidden from detection. In Fig. 1, we can see a compressor air cooler that has been subject to frequent high-pressure cleaning using compressed air blow wands. And due to the stresses involved with the cleaning, it has finally started leaking. The compressor operators never thought to look within the compressor assembly itself for any leakage — and when in the compressor room, they could not hear the leak due to the cooling fan noise.
Some air leaks are not obvious — or due to the location, they are muffled due to enclosures or coverings. Fig. 2 shows a typical duct tape repair job that will not ever repair the leak, but this poor maintenance choice does makes it very difficult to hear, even with ultrasonic detection.
Some points about leaks:
- Leaks can form within compressed air equipment like compressors and air dryers; sometimes enclosures must be opened to detect them
- Taping a leak is never an effective repair practice
- Sometimes a large leak or air use can swamp out the acoustic signal from many smaller leaks; redo the leakage detection once a large leak is repaired
- If there are underground lines, perform regular isolation blow down tests to ensure there is no leakage, especially if the lines are not corrosion protected, and
- Leaks can form in ceiling mounted equipment and piping and be very hard to detect from the floor.
It is essential that some sort of ultrasonic device be used to detect leakage, as normal human hearing will not do a good job in a normal industrial environment. Affordable ultrasonic leak detectors are available, some for under $500, so there is no excuse for not having one. Running a frequent leak detection and repair program is important to keeping your compressed air system running efficiently.