Industrial machinery and air compressors are prone to wear like any other system. Damage to air compressors can take the form of moisture blockages, corrosion, material failure and air leaks.
Air leaks are usually found at joints or component junctions of the pneumatic circuit, but sometimes they can be difficult to detect because they are hidden. In other cases, the sound of compressed air escaping can be masked by the noise from surrounding machinery, such as cooling fans.
Knowing what causes air leaks and how to find them will help you locate them and prevent downtime and energy losses.
What Causes Air Leaks?
Air compressors are subject to variations in airflow and high-pressure cleaning as part of their maintenance. Because of these stresses on the system, air leaks can occur, which are difficult to detect because they are out of sight.
Air leaks can often be traced back to faulty connections, wrong connection types and improper sealing. Other reasons include cylinder bore wear, broken pressure switches and loose unloader valves.
Faulty connectors are one of the main causes of air leaks because they are the parts of the system where pressurised air and fluid are constrained or transferred. Checking connections along the air system and tightening loose or poorly fitted parts will prevent minor leaks from developing. Loose connectors and fittings produce wheezing noises as air passes through – which can be detected with the right ultrasonic equipment.
Why You Should Look For Hidden Leaks
Checking the air compressor for leaks will prevent wasted energy from air seeping out of the system. Air compressors consume a significant amount of electricity. It is accepted that the average compressor will have around 10% leakage – this may sound high, but a leak in the system will increase this figure to 40 or 50%.
Drop In Air Pressure/Lost Compressor Power
A drop in air pressure is another sign of unaddressed air leaks. Left unresolved, these leaks will make the whole system lose pressure, affecting pneumatic equipment and production output. Oil leaks in the compressor cause it to burn oil more rapidly, resulting in lost compressor power.
Increased Wear And Costs
Air leaks force more frequent cycling in the system because pressure drops make the compressor stop and resume cycling to compensate. This over-cycling wears out the system, eventually leading to unexpected outages. Given that leaks cause a loss of air/gas in the factory, this will adversely affect the plant’s energy costs as well as cause long-term damage to equipment.
Hidden Nature Of Leaks
The industrial environment around air compressors often masks the faint sound of air leaks, making them difficult to detect. Finding hidden leaks requires specific equipment to pick up on their faint sound, such as ultrasonic acoustic detectors. Without thorough checking for air leaks, they will turn into a hidden cost for plant operators.
Why You Should Repair Leaks
Energy and productivity losses are the main reasons to address air leaks. However, leaks can also bring contaminants into the system and lower production quality. For this reason, it’s not only important to address leaks from a cost angle but for hygiene and productivity as well.
Air leaks get worse over time if they are not remedied, resulting in small leaks shortening the lifespan of the compressor. The constant pressure on the compressor will also wear the rest of the system’s equipment.
How To Find Leaks
Finding air leaks requires the right equipment, because the punctures produce a faint sound and are often out of sight. Plant operators use ultrasonic acoustic detectors, which can pick up the high-frequency hissing sound that air leaks produce. These portable devices consist of amplifiers, directional microphones and audio filters, as well as visual indicators or earphones to hear the source of the leak.
The portable nature of the equipment provides for easier and more accurate detection of leaks because the device can reach spaces above and below the compressor. Ultrasound has a directional transmission signal, emitting louder signals the closer it gets to the source. In this way, leak sites are quickly found by scanning the area where the equipment is situated or the leak is suspected. It’s also possible to carry out tests while equipment is in use to identify different types of leaks. Ultrasonic devices for leak detection are easy to operate and don’t require much instruction to use.
Sometimes it may be necessary to open the air compressor or dryer to look for leaks in the unit if the source is not found externally.
Another method involves running the air compressor up to full pressure without any output and then measuring the length of time before the pressure drops and the compressor switches on again. This method provides for a clear indication of air leaks in the system.
Regular isolation blowdown tests around underground lines of the air compressor also ensure there is no leak present – particularly if lines are not insulated against corrosion.
Taping leaks is ineffective and can block out the sound of smaller leaks. Since leaks usually occur at joints, preventing leaks can simply mean tightening a connection. More complex repairs involve replacing faulty couplings, fittings, hoses, water drains, or traps. Many instances of leaks can be traced to inefficient application of thread sealant.
Selecting quality fittings, tubing and disconnects for the compressor from the start – and ensuring they are properly installed – will prevent leaks at the source.
Non-operating equipment can be the source of a leak. The solution is to isolate equipment no longer in use with a valve in the distribution system.
It’s also possible to reduce leaks by lowering the demand air pressure of the system to reduce the leakage rate until it is repaired.
Establishing a cost-effective programme for the detection and repair of leaks is necessary to ensure that systems run without numerous unattended leaks. This simple step can bring down the average leak rate to under 10%.