Compressed Air Leak Detection and Repair – Air Compressor Manufacturers

Compressed air leakage is the most common energy waste in factories. Also the most easily ignored.

A single 3 mm diameter leak point, at 7 bar pressure, costs roughly $600 a year in wasted electricity.

A 10% leak rate is considered normal. 20% is very common. Above 30% happens too. How many leak points your factory has, do your own math.

Leak Detectors

Ultrasonic leak detectors are currently the most effective tool. Leaks produce ultrasound that human ears can't hear. The instrument can.

SUTO and SDT are widely used on the market. Domestic brands have been coming up these past few years. Big price gap. Imported ones do have better sensitivity and interference rejection. Shows when finding tiny leaks. For big leaks, all pretty much the same.

Buying a leak detector doesn't mean you can use it well. Too much interference on site. Motors, bearings, pressure regulators all produce ultrasound. Mixes with the leak signal. Beginners can't distinguish. Frequent misidentification. Some factories buy the instrument and have a random person sweep once and call it leak detection. Results aren't reliable. Telling leaks from interference takes practice. Signal characteristics are different. Listen enough and you can tell.

On that note, detection distance on leak detectors is another trap. Manufacturer brochure says it can detect at such-and-such meters. That's lab conditions. Site pipe is three or four meters overhead. Standing on the ground, signal is too weak. High pipes still need to get close. Scissor lift or scaffolding. Some spots genuinely unreachable. Just have to skip them.

No leak detector, use soapy water. Old method. Apply it, bubbles mean a leak. Slow, but works. Shutdown testing works too. Pressurize the system, stop the machine, watch how fast the pressure gauge drops. Tells you if the overall leakage is bad. Specific locations still need to be found.

Industrial leak detection — Ultrasonic leak detection equipment

Where Leaks Happen

Quick-connect fittings leak a lot. Convenient, yes. Quality all over the map. Cheap ones have poor seals. Degrade in no time. Some factory purchasing only looks at price. Bulk-buy off-brand. Leak rate stays high after that. Doesn't actually save money when you add it up.

Tube not inserted deep enough also leaks. Quick-connect fittings have a marker line. Tube needs to go in to that mark. A lot of people don't care about this. Push in, feels tight, done.

Threaded connections, mainly a PTFE tape issue. Not enough wraps, wrong direction, uneven application, all cause leaks. Also situations where the threads themselves are worn. After several rounds of disassembly and reassembly, sealing degrades. Can't fix that. Replace with new.

Hose aging and cracking. Especially at bends. PU hose after two or three years shows fine surface cracks. Where hose meets fitting, if the clamp isn't tight, very high leak probability. On that note, hoses getting run over, hit, or cut isn't uncommon either. Forklifts driving around the workshop, it happens.

Valve leaks, two types. Stem seal leaking outward. Can see it, can hear it. Seat wear causing poor shutoff is internal leakage. Gas passes through inside. Can't tell from outside. Internal leakage is more annoying. Can't find it without disassembly. Solenoid valve spool wear is also internal leakage.

Cylinder seals worn, high-pressure side bleeds to low-pressure side. Cylinder action slows, insufficient force. Operators usually report insufficient supply pressure. Ask for pressure to be turned up. Turned up, leakage gets worse. Then feels still not enough. Turn up again. Watch for this.

Oh, and there's one spot that gets overlooked. Where compressed air piping passes through walls. Pipe goes through, sealed with cement or foam. If the joint inside is leaking, nobody knows. Some old factories, piping modified over and over. What's inside the wall, nobody can say.

Repair

Most leak points are simple to fix. Tighten what's loose. Replace seals. Cut off or replace hose. Cost of a few dollars to a few tens of dollars.

The hassle is spots you can't reach, can't shut down, or buried inside equipment. These wait for a maintenance window. Note them down first. High-volume leaks get priority. Small ones can be batched. Some old piping has too many leak points. Fixing them one by one is worse than replacing the entire section.

Leak repair, sounds uncomplicated. Execution depends on the person. Some maintenance workers are thorough. Fittings torqued properly. PTFE tape wrapped the right number of turns. Some just go through the motions. Not leaking right now counts as done. Two months later it's leaking again.

Pipe fitting repair — Compressed air fitting maintenance

Detection Frequency

A lot of factories only check for leaks after something goes wrong. Leak points are constantly forming. What you fixed today might leak again in a few months. Newly installed equipment might have issues from the start. Wait until there's a problem and it's too late.

Full survey once a quarter is reasonable. Record every leak point found. Location, size, date. Next survey, compare. Fixed or not. Recurrence or not. Over time, patterns emerge. Which locations keep having problems. Which type of fitting is unreliable. Future purchasing and installation can be targeted.

Some factories outsource leak detection to the compressor service provider. Saves hassle. But the results and recommendations from the service provider need your own judgment. Service providers have different positions. Some sell instruments. Some sell parts. Some do maintenance contracts. Perspectives differ.

Industrial maintenance — Systematic leak detection program

Leak detection done seriously vs. done as a formality, huge difference. Same system. Careful survey finds dozens of leak points. Casual sweep reports a handful. Whether the person doing the detection has experience. Whether they're conscientious. Directly determines the result. Some factories survey every year. Leak rate never comes down. The problem is usually right here.