Oil-lubricated air compressor vs. oil-free compressor – which is better?

There are some environments where air purity is critical, and any oil contamination within the air can cause the final product to spoil or damage the production equipment in use. Usually specified with safety in mind, oil-free compressors offer a safe solution for either manufacturing personnel or the end user where air purity is critical. We take a look at oil-lubricated air compressors vs. oil-free to see how they each stack up.

What is an oil-free compressor?

Oil-free air compressors have been developed for use in applications where oil within the compressed air would be unacceptable. An oil-free compressor is not completely free of oil. However, there is no oil in the compression chamber and the components that require oil for lubrication, such as bearings and gears, are isolated from the compression chamber itself. This keeps the resultant compressed air 100% free of oil contaminants.

Whereas an oil-lubricated compressor would usually use oil for cooling purposes, in a rotary screw oil-free compressor there is usually an air cooler after each stage of the process. Some oil-free compressors use injected water to remove the heat created by the compression process.

What is an oil-lubricated compressor?

An oil-lubricated compressor uses oil for lubrication and cooling, which helps to reduce friction, dissipate heat, and enhance efficiency by injecting oil into the compression process. The oil is then separated from the compressed air to provide clean, high-quality air. These compressors are commonly used in industrial and manufacturing settings due to their reliability and long-term use.

To ensure an oil-lubricated compressor never contaminates the compressed air, proper and regular air compressor maintenance must be done.

Oil-lubricated air compressor vs. oil-free

As with all things, there is never just one solution to fit every scenario perfectly. Oil-free compressors have distinct advantages in some environments but are not necessarily the best solution for every business or application. We’ve looked at the advantages and disadvantages of both oil-free compressors and oil-lubricated compressors to help provide context.

What are the advantages of oil-free compressors?

Non-contaminated air: Given that this is the key reason for their existence, this must be included. Industries such as food processing, electronics and pharmaceuticals are common users of the oil-free compressor. Filters can be used as a solution to creating oil-free air, but most processing businesses that need oil-free compressed air choose to go with oil-free compressors.

Low-cost: Because they’re simpler in design than oil-lubricated compressors and with fewer parts, oil-free compressors are, generally, less expensive to produce.

Lower maintenance demand: As there are fewer moving parts and less oil to change, there is a lower chance of problems arising, and needing to be fixed, as well as less time to be dedicated to servicing and maintenance.

What are the disadvantages of oil-free compressors?

Limited durability: Oil-free compressors generally have a shorter lifespan compared to oil-lubricated systems because they experience more wear and tear because of the lack of lubrication.

Higher operating temperatures: Oil-free compressors often run at higher temperatures which can impact efficiency and potentially lead to overheating issues.

Expensive maintenance: While oil-free compressors are, generally, lower in cost, their maintenance costs may be higher because they require more frequent replacement of components.

What are the advantages of oil-lubricated compressors?

Longer life span: Oil-lubricated compressors are more durable and are well suited to industrial environments and long working hours. In comparison, many oil-free compressors can only cope with low usage levels and will need to be replaced more often.

Lower noise levels: The lubrication in oil compressors means that they produce far less noise than their oil-free counterparts, which is often a point of concern in industrial manufacturing environments.

Less heat production: The oil helps to remove heat from the process of compression in oil-lubricated compressors. This means that they produce less heat during operation and help to maintain a more consistent processing environment.

What are the disadvantages of oil-lubricated compressors?

Oil contamination: Oil-lubricated compressors can, occasionally, introduce oil contaminants into the compressed air, which may not be suitable for certain applications.

Maintenance complexity: These compressors require regular oil changes and oil filter maintenance which makes them more complex to maintain compared to oil-free compressors.

Environmental impact: The disposal of used compressor oil can be an environmental concern if it’s not handled properly. It requires proper disposal methods to prevent damage to the environment.

Oil-free and oil-lubricated compressors at Glaston

It is clear, then, that when it comes to the question of oil-lubricated air compressors vs. oil-free compressors, there is not a straightforward answer that suits every situation. The application is the most critical factor in terms of safety and hygiene for those who opt for an oil-free compressor solution, but where lifespan and operating conditions are paramount, it may be that the oil-lubricated air compressor makes more economic sense overall and is more suited to the industrial application in question.

If you would like to find out more about Glaston’s range of oil-free and oil-lubricated air compressors, contact us now on 01695 51010 or email us at info@glaston.com.