Small parts make a big difference

22 March, 2017

Few would deny the logic of ensuring the continued performance of production equipment. However, recent findings show that not everyone is aware that the quality of spare parts can have a significant effect in terms of costs and efficiency. At a time when capital expenditure and budgets are under increasing pressure it is vital that manufacturers guarantee continuous production, and to do so they need to ensure their machinery is properly maintained.

In the case of compressor components, it is essential that high quality systems should be maintained and serviced with genuine spare parts to reduce the risk of performance dips, over-usage of energy and reduced lifetime – all of which can have a negative impact on the compressor owner’s capital investment.

Here are just some examples of what happens when original spare parts or recommended lubricants are not employed:

Lubricants

The optimal operation of a conventional screw compressor is dependent upon lubricants to reduce wear and to seal, cool and clean. Compressor oils comprise base oils combined with a balanced selection of specific additives relative to the viscosity, solvency, volatility, oxidation resistance and surface activity requirements of the oil circuit design relative to anticipated operational conditions. In much the same way as all other components of a modern compressor, these lubricants are developed, verified and field tested for suitability to specific models or ranges of compressor solutions. Therefore, it is vital that the additive balance is exactly right in every case.

Non-specific substitutes are likely to cause problems. The wrong specification can result in poor lubrication of the compressor screw element which does not seal properly, allowing air to ‘slip’ back and be re-compressed. Each compression cycle reheats the air increasing the operational temperature of the compressor thereby reducing its efficiency and pushing up its SER (Specific Energy Requirement) level. At the same time the increased heat may result in oxidisation of the oil, reducing its efficacy and contributing to sludge blockages in the oil circuit.

Furthermore, incompatibility with rubber or metal parts can create leakages and the chances are that high surface activity will take place within the oil separator.

Air filters

These are a compressor’s first line of defence for its oil circuits and compression elements against external contamination. When correctly matched to a compressor system, they are capable of a >99.9% separation efficiency and able to extract all particles larger than 3micron in size from the incoming air. But non-genuine units, either of competitive design or actual ‘pirate’ parts, may create problems caused by ingress of unfiltered air. These stem either from dimensional differences, whereby incompatibility of the filter element to its housing increases intake of unfiltered air, or the inferior quality of the filter paper. A chain reaction is created affecting the efficiency of the downstream air/oil filter and the air/oil separator, resulting in significant pressure drops.

In much the same way, non-genuine oil filters too are likely to exhibit lower separation efficiency, inadequate sealing and cracking of the filter paper pleats, all resulting in a damaging unfiltered oil flow. Absence of a bypass valve can also lead to clogging, overheating and breakdown of the compressor element.

Electrical components

Cheaper electrical components are equally tempting but not without risk. A rewind operation for a burned out electric motor may be attractive but a subsequent 10% loss in efficiency may prove less so − replacement with an updated, high-efficiency unit can prove a better proposition. In other areas, system control issues are often found to be the consequence of fitting cheaper but unreliable pressure transducers that are responsible for substantial increases in energy consumption.

Small parts can make a big difference

Well before any compressor reaches work-life retirement age, the simple truth is that only by using original spare parts can its designed performance and efficiency be maintained at the same level as when it was purchased. In that way, investment is not compromised and neither is the compressor’s quality output. What’s clear is that small parts can make a big difference.

www.atlascopco.co.uk