Plant & Works Engineering
What type of compressor lubricant do I need?
Published:  08 April, 2015

Compressor oils are standardised to DIN 51506. High density (HD) oils should not be used to lubricate compressors as they tend to emulsify and therefore quickly lose their lubricating properties. Mineral and synthetic oils can be used. Mineral oils have a useful life of around 2000 to 3000 operating hours under normal operating conditions.

Synthetic oils however can be changed at longer intervals. In piston compressors, synthetic-based oils allow compressor running times of up to 8,000 operating hours. In screw compressors, the lifetime of mineral oils is typically about 3,000 operating hours, while synthetic oils can reach a lifetime of up to 9,000 operating hours. Synthetic oils have a much higher oxidation and ageing stability than mineral oils, which results in the increased lifetime. This also prevents unwanted deposits in the oil circuit.

Other advantages of synthetic oils are their lower volatility, which results in lower oil carry over and residual oil content, especially at high temperatures, and a better viscosity-temperature-behaviour. This ensures good and stable lubrication in a wider temperature range.

When compressed air is used in the food or pharmacy industry there’s the risk of accidental contact with the product. In this application you should use USDAH1 oils as they fulfil the strict requirements of these industries.

The oil level of the compressor must be checked regularly and the first oil change is made after the running-in period, which is approximately 300 to 500 operating hours.

Compressors must not be operated with too little oil as even a short trial run without oil (for example to check the direction of rotation) can lead to damage. The oil filter must be cleaned or replaced each time the oil is changed.

Answer provided by BOGE Compressors Ltd