Probably the most common and at the same time most underestimated problem in compressed air systems is energy losses caused by leakages. A quiet hissing noise at a screw connection here, a leaking coupling there – what goes unnoticed on the noisy production shop floor adds up to considerable costs over the year. Costs that are avoidable. A single, tiny leakage with a diameter of just one millimetre at a network pressure of 6 bar already causes additional costs of almost 180 euros per year. An audit at a typical production plant showed how quickly these small losses add up. 278 leakages were found, amounting to a total of almost 50,000 euros per year. This is money that literally vanishes into thin air. Leakages often go undetected because no one is really looking for them. However, anyone who actively sets out to detect leakages quickly discovers that there is hardly anything that reduces energy costs faster and more permanently than eliminating them. Eliminating leakages not only saves money, but also increases the availability and stability of the entire system.
"Better be on the safe side and have a little bit more pressure ". This is the widely held belief of many operators. The compressor is often set to a significantly higher pressure than is required for the application in order to avoid pressure losses caused by long pipes or filters. For example, if a compressor is operated at 7.5 bar, even though the machine only needs 6 bar, that represents a continuous, expensive safety reserve. Every bar of overpressure increases the compressor's energy consumption by 6-8%, day after day, year after year. A practical example shows the effect: in a plant with annual compressed air costs of around 780,000 euros, lowering the actual pressure by just 1 bar led to savings of almost 47,000 euros per year. Safety reserves are important, but system pressure that is too high is an expensive solution in the long term. A precise analysis of how much pressure is really needed at which point immediately saves costs, without jeopardising process reliability.
In addition to system-wide measures, taking action directly at the machine can often also offer great potential. Example of a typical blow moulding application that dries or cleans components on a conveyor belt. Previously, a nozzle would blow continuously and consumed 533 standard litres per minute (Nl/min) even if there was no component in the station. This resulted in annual costs of over 7,000 euros for a single work step. Two simple adjustments have fundamentally improved the process:
- Demand-orientated control:
A sensor now recognises when a component reaches the station.
- Pulsed air blast:
Instead of blowing air continuously, air is only blown briefly and selectively (e.g. 0.5 seconds ON, 0.5 seconds OFF) while the component moves past the nozzle.
This reduced the compressed air consumption to around 260 standard litres/min. The annual costs fell to less than 1,800 euros – a saving of over 5,000 euros per year! This investment paid for itself in just a few weeks. This example clearly shows you how even small optimisations to the application can have a big impact, and why it is worthwhile to take a closer look.