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What Is an Oil-Free Compressor?

K'Lee Banks
K'Lee Banks

An oil-free compressor is only one of several types of compressors available. It works the same way as a standard air compressor, and may even look very similar on the outside; internally, however, it contains special seals designed to keep the crucial lubricating oil away from the compressed air. The moving parts inside the compressor require lubrication to reduce the friction. Lubrication is essential in adequate amounts, regardless of the type of compressor, in order to prevent failure of the parts. The term oil-free refers to the air that the compressor produces, not the machine itself.

Certain compressor designs, primarily older ones, have a minor flaw. This flaw is that compressed air has a tendency to become contaminated with very minute amounts of the lubricating oil. As with most inventions, the air compressor design has steadily improved over time to eliminate these flaws. The oil-free compressor is designed to prevent any compressor oil from coming into contact with the compressed air. This process results in clean, dry air with no contamination, which is a crucial requirement in certain applications.

Woman holding a book
Woman holding a book

Not long ago, air compressors were prone to producing air with slight amounts of oily residue. With the invention of the oil-free compressor, however, oily residue is no longer a concern. It is important to keep in mind, however, that all moving parts need some sort of lubrication. Today’s ingenuity keeps the oil out of the compressed air and in the machine where it belongs. While certain applications, such as pneumatic tools, benefit from certain amounts of lubrication, other applications suffer adverse effects when air is contaminated with oil, even in small amounts.

To better understand the significance of the oil-free compressor, one has only to consider specific examples of the frustration or adverse effects that oily residue can cause. For instance, during auto-body work such as painting a car, the quality of the job can become compromised — causing inferior results — if tiny drops of oil get mixed in with the paint. The main unwanted outcome is that paint will not stick to oil. Uncontaminated air, therefore, is essential for these types of applications.

On occasion, one might need to perform compressor maintenance. This may involve changing the lubricating oil. Similar to changing the oil in a car, this maintenance must be done periodically to prevent serious damage to the oil-free compressor. Lubrication is essential whenever there are moving parts involved.

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