Air Oil Separators

The compressor oil, which is primarily used for dissipating the compression heat needs to be separated from the air again. Any oil that remains in the compressed air after the air oil separator will result in increased oil contamination leading to increased servicing of compressed air lines, condenser and condensate processing.

High residual oil content increases oil consumption and operating costs with lower quality compressed air. Less carry over also means that fewer oil contaminants are passed to condensate drains, and therefore the environmental impact is minimized.

The oil is first separated from the air in the air receiver by centrifugal separation with very high efficiency. The oil drops to the bottom of the receiver by gravity. The air oil separator element will further remove the remaining oil drops from the compressed air.

Micro-glass-fibre layers separate drops of oil from the compressed air and return them in large drops to the oil circuit of the compressor. The separation process is effective right down to the sub micron range. Vapor oil particles are not separated.

Depending on the size of the drops, various physical separation effects result in the fine drops being adsorbed by the micro-glass fibres. The number of fibres, fibre diameter, and flow velocity has a major impact on separation efficiency.
The larger drops produced in the first separation phase by the coalescence of fine drops are pressed through the glass-fibre layer and sink to the bottom on the dry side under the influence of gravity. The remaining air-borne proportion of smaller drops is separated in the second phase.

Selection of the correct materials in conjunction with low flow resistances ensures that nearly all oil drops left in the airflow can be separated or drained off. This also applies to load fluctuations around the nominal utilization point. Oil flows from the outside to the inside of the separator element and the drainage oil is drawn off on the dry side through a centrally positioned scavenge pipe, running from the base cup of the separator.

For every additional 1 bar pressure drop, an additional 7% power is required.
The air oil separators available at Field Air Compressors are designed to reduce the initial restriction, contributing to the most efficient compressor performance.

The service life of an air oil separator is defined as the number of hours it takes to reach a pressure drop of 0.8 bar.
The rise in flow resistance primarily depends on the cleanness of the oil and the quality of the air filter.
It is highly recommended to use our approved compressor lubricant. Dirt deposits, e.g. old oil products, air contamination or abrasion reduce the service life of oil separators. If an oil separator has a higher initial pressure drop it will also reduce the service life. In this case not only the cost of the more frequent changing of the separator element is important, but also the accumulated extra fuel consumption is significant. As the service life is affected by a lot of external parameters, we will focus more in detail on the measures to be taken to secure an economic service life.