Step 4 for Compressed Air Analysis : Locating leaks and fixing them
The expensively cleaned compressed air that escapes through leakages is costly and strains the base load of compressors. Therefore it is important to analyze and contain these leakages to reduce losses.
Where are the leaks located?
A properly installed stainless steel pipe system, that is welded or bolted via flanges, are highly reliable and rarely prone to leakage as they do not have flexible wear and tear parts, and can handle higher temperature and pressure changes, among other reasons. Therefore, majority of the focus in detecting leaks should be at machinery and connections.
Machinery: Maintenance units, valves, cylinders, limit switches and pneumatic components can leak when not regularly maintained or check
Connecting elements: Flanges fittings, couplings, hoses, hose connections and unions are all components that causes leakage when they are damaged, loosen overtime due to vibration or mechanical stress.
How to effectively locate and assess leaks
The most common method in detecting air leaks is via ultrasonic waves that is being generated, which is inaudible to the human ear. Ultrasonic leak detectors make these waves audible and visible from a distance of 6-10 meters depending on the size of the leak. Once the leak is precisely located, the level, distance and system pressure is able to provide indications of loss volume flow. With the help of leak reporting software, one is able to act economically to prioritize costly leaks and prepare on maintenance capacities, spare part availability and production breaks.
Tips for minimizing small leaks that would be uneconomical to repair
Tip 1: Utilize automatic shut-off valves on machines and manifolds to disconnect leaks from supply as soon as production stops. Therefore, leaks would only take place when production is taking place.
Tip 2: Reduce line pressure as much as possible to minimize leakage losses, as higher pressure at a leakage increases loss volume flow.
Leakage rates can be classified based on leakage diameter and line pressure, as shown below:
From there, the costs of the leakages over an interval of time can be determined:
Cost = Compressor specific power x Leakage rate x Electricity price x Operating hours
A possible economic way of leak detection is to spray liquid soap on pipelines and check for air bubbles. However, such methods is not suitable in compressed air analysis as:
- It is not possible to quantify the leakages
- It is not possible to a large amount of compressed air lines in the production floor, especially when they are often fastened to walls or ceilings.
- The chemical may contaminate the air supply and affect product quality, hygienic standards.
Using an ultrasonic air leak detector equipped with a 40 kHz transducer, whose output voltage changes in proportion to sound pressure, ultrasound generated from the friction of compressed air exiting at pipeline can be reliably detected and quantified.
The CS Instruments Ultrasound Camera for Leak Detection LD 500 is equipped with 30 MEMS microphones, leaks can be accurately quantified by distance, system pressure and ultrasound level (dB).
The portable leak detector allows you to photograph and label leakages, while automatically adjusting sensitivities to eliminate background noise from the environment. The data obtained can be exported via USB and be interpreted via PC software "CS leak reporter", which generates a clear report in compliant with ISO 50001, detailing all leaks location, size of leakage, costs and action taken.
Even with it's advanced features, ultrasonic sound detection has its' limitations with environmental noises such as electric motors, periodic blowdown from valves and cylinders, and reflectance on walls. CS instruments offers a variety of accessories to counteract this problem, and allow conveniences in quickly and effectively detecting leaks:
