A Compressed Air Leak Detector is a device specifically designed to find leaks in compressed air systems. It works by listening for ultrasonic sounds and is often called an ‘ultrasonic leak detector’.
Compressed Air Leak Detectors are frequently used for compressed air audits. If you’re not familiar with what a compressed air audit is, let me explain.
Compressed Air Audits
The goal of a compressed air audit is to reduce energy costs of your compressor installation. It does so by looking at the supply and demand side of the compressed air system.
The supply side includes your compressors, the pressure set points, the control system (especially when there are multiple compressors) and more. The demand side of the audit looks at things like compressed air usage, changing to equipment that use less compressed air, lowering pressure drop in the piping system, and finding (and fixing) compressed air leaks!
Compressed Air Leaks
All compressed air system have leaks. Leaks can be anywhere including:- pipe joints, valves, equipment and (quick connect) couplings. It is said that in a typical industrial compressed air system, 20 – 30% of compressed air is wasted because of leaks.
When you consider that 70% of compressed air costs is electricity, you will understand that a 20% leakage is a HUGE waste of electricity and money.
A typical 100 kW air compressor system uses around £80,000 per year in electricity, therefore 20% compressed air leakage is the equivalent of £18,000 per year – wasted!
Finding Compressed Air Leaks with a Compressed Air Leak Detector
You can find big leaks simply by listening for them. Do this when the factory is shut down, in the weekend or evening. You will be able to identify many big leaks this way but it is harder to find the smaller leaks and you will not notice any leaks in the overhead piping system.
Most sound coming from a compressed air leak is ultrasonic – it is of such high frequency that we can not hear it. A compressed air leak detector converts the ultrasonic sound to a lower frequency that humans can hear.
As a rule, only 5% to 10% of air leaks are in the piping system and most leakage occurs at the working floor (inside and near the pneumatic equipment). Therefore, it is important to leak test both the pipework and production equipment.
It is easiest to find a compressed air leak with a leak detector that has a headphone and that amplifies and lowers the frequency of the sound. With those devices you can really hear the leak, instead of some beeping sound or indicator.
From Ultrasound Level Readings to Leak Air Flow
The leak detector usually gives a reading in dB (decibel) to indicate the loudness of the compressed air leak. This dB level is converted into a leak size. The conversion factor differs between brands and models but it will always be an estimate and nothing more. For example, a 60 dB reading might convert into a 2 cfm (56 l/min) leak at 100 psi (7 bar).
Buying a Leak Detector
An ultrasonic compressed air leak detector will cost you anywhere between £500 to many thousands. The more expensive are mostly units that can be used for many applications (bearing monitoring, electrical equipment monitoring, hydraulics monitoring, and of course compressed air leak detection). The cheaper units are mostly dedicated leak detectors.
If you would like to discuss compressed air leak detection or buy a ultrasonic leak detector please contact us today.