Oil vs. Oil-Free Air Compressors


Air compression is essential for companies in several industries, including the pharmaceutical, automotive, food and beverage, and agricultural industries. There are several air compressor variations; for instance, some handle heavy-duty applications better than others. However, you can typically place air compressors into two major categories: oil-lubricated compressors and oil-free compressors.

Oil-Lubricated Air Compressors

All air compressors have moving parts, and therefore, they must be lubricated. If you do not adequately lubricate your compressor, it will fail to function correctly. Oil is the most common lubrication material used for machinery, and traditional oil-lubed compressors utilize this tried-and-true medium.

Oiled compressors are rugged and durable, and their oil usage makes them ideal for industrial applications. They tend to produce a lot of heat, and the oil doubles as a coolant. Because their parts are oil-lubricated, oiled compressors are typically quieter than their oil-free counterparts. Although, people often overstate the loudness of oil-free compressors.

Oil-lubricated compressors are versatile and reliable, but they have some downsides. For one, they require a lot of maintenance, and operators have to oil them manually and regularly. They are expensive, and their large size makes them impossible to transport. They have to be permanently installed at a single site.

The most glaring drawback of oil-injected compressors is the risk of oil contamination. The oil used to lubricate, seal, and cool the machine leaves oil content in the compressed air that must be removed via separation or filtration. In industries where air purity is critical (particularly in sterile environments), even the tiniest drop of oil risks contamination.

Oil contamination can cause product spoilage, rework, production downtime, and even damage to your brand’s reputation if the problem is not discovered and corrected. This is where oil-free compressors come into play… 

Oil-Free Air Compressors.

Oil-free compressors use an alternative sealing, cooling, or lubrication medium, such as water. They are designed in such a way so that the air compression takes place across multiple stages. Their use of alternative lubricants eliminates the risks and associated costs of oil contamination.

Companies use oil-free compressors for applications where even the slightest bit of oil carry-over is unacceptable. For example, it is vital that pharmaceutical manufacturing companies have no hydrocarbons in their products or the air of their production facility. The same is true for food and beverage companies, such as bottling companies and food packaging manufacturers, where the air comes into direct contact with the product.

Here is a list of industries and applications that typically require oil-free air compressors to avoid oil contamination and the issues associated with it.

  • Medical/Hospitals
  • Pharmaceuticals
  • Food & Beverage
  • Life Science
  • Chemical
  • Power Generation

Eliminating the risk of oil contamination is only one of the benefits of oil-free compressors. Unlike oiled compressors, they can withstand freezing temperatures; they are smaller and designed to be portable; oil-free compressors require little maintenance and do not have to be manually lubricated, and they are less expensive.

Common Oil-Free Compressor Misconceptions

A few myths are floating around that people use to discredit oil-free air compressors. We’re going to debunk a few of these myths.

Oil-Free Compressors Are Significantly Louder

We can’t deny that oil-free compressors used to be much noisier than their traditional oil-lubricated counterparts. However, current-day oil-free compressors are not nearly as loud as people make them out to be. While they are louder than oil compressors, the difference is not as great as you may have been lead to believe. Today’s oil-free compressors utilize direct-drive, dual-piston pumps and sound-reducing technology, making noise essentially a non-issue.

Oil-Free Compressors Have Shorter Lifespans

The biggest argument against oil-free compressors is their shorter life expectancy. Again, this may have been the case back in the day, but now, the compressor’s lifespan is no longer an issue. Oil-free technology has advanced significantly in recent years, allowing these compressors to run cooler and last longer. Plus, they require less maintenance than oil compressors.

Oil-Free Compressors Run Hotter

While it is true that oil acts as a heat-transfer material and helps keep compressors cool, the dual-pump designs of oil-free compressors allow them to achieve the desired CFM/PSI in half the number of revolutions as it takes an oil compressor.

Oil-Free Compressors Can’t Withstand Extreme Conditions

We can’t deny that oil-lubricated compressors are better able to withstand scorching environments, as they can dissipate heat quicker than oil-free compressors. However, oil-free compressors actually withstand extremely cold temperatures better than oil compressors do. There is no worry of the oil in the compressor turning into sludge due to the cold.

Oil-Free Compressor Technology

Oil-free compressors compress air through the screw rotation without an oil seal. Thus, they typically have lower maximum discharge pressure. However, multi-stage oil-free compressors compress air using multiple sets of screws. The types of technologies used in oil-free compressors include the following.

  • Water-injected compressors
  • Two-stage dry screws
  • Single-or-two-stage oil-free pistons
  • Centrifugal compressors
  • Rotary screw compressors

Compare and Contrast the Pros and Cons of Oil and Oil-Free Compressors

Advantages of Oil-Lubricated Air Compressors

  • Better suited for heavy-duty and industrial applications.
  • Able to withstand extremely hot environments

Disadvantages of Oil-Lubricated Air Compressors

  • Very heavy; permanently installed at a single location
  • Require far more maintenance and need to be oiled regularly
  • More expensive to lubricate
  • Oil contaminates the surrounding air

Advantages of Oil-Free Air Compressors

  • Compact and portable design
  • Don’t require manual lubrication
  • Easier to operate
  • Less expensive
  • Suited for applications that could be jeopardized by oil contamination
  • Better for non-commercial purposes
  • Able to withstand frigid environments

Disadvantages of Oil-Free Air Compressors

  • Can’t handle heavy-duty applications as well as oil-injected compressors
  • Smaller tank size

While both oil and oil-free air compressors have pros and cons, in the end, your application will most likely be the determining factor of which one is better suited for you.

The Future of Compressed Air

With operational facilities having to meet increasingly stringent quality standards and stay in compliance with expanding regulations, we predict that oil-free compressors will play an essential role in the future of compressed air.

There has been a significant oil-free shift in air compressors, and Gardner Denver is at the forefront of this movement. C&B Equipment is proud to be a licensed distributor of Gardner Denver’s oil-free compressors. If you are interested in making the transition to an oil-free compressor or need to purchase your very first air compressor, C&B Equipment has got you covered!

Comments for this post are closed.