Oil vs. Oil-Free Air Compressors | An Expert Guide

No matter your industry, you likely have a need for air compressors. For everything from pharmaceutical applications to food and beverage processes, air compressors provide the necessary function of pressurizing air. That air can then be used to power different equipment and systems, such as nail guns, blast equipment, conveyor systems, painting equipment, and so much more.

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When considering air compressors, you will note they fall into two main categories &#; oil-flooded and oil-free. Both categories differ in terms of operation, applications, benefits, and downsides. Understanding how each kind of air compressor works is key so that you can choose the best one for your specific needs.

Oiled Air Compressor Overview

Every air compressor &#; oil-flooded or oil-free &#; features numerous components that effectively pressurize air and turn it into power. Without lubrication, they fail to operate, and your air compressor will be useless. Like dozens of other machinery, an oiled air compressor uses oil to provide lubrication to the various parts of the system.

These air compressors can operate on two different types of oil &#; mineral and synthetic. Mineral oil is the product of a petroleum refining process, while synthetic oil is a laboratory creation.

Mineral oil is typically the better option for small-to-medium compressors that don&#;t operate continuously. A synthetic lubricant is more suitable for industrial air compressors because it provides more protection against overheating due to its wider temperature variations.

During operation, an oil-flooded reciprocating air compressor pulls in air via a piston. Then, the air is pushed out of the chamber and compressed into a storage tank. Here, oil is critical to ensure the piston has enough lubrication to move &#; in an oil-flooded rotary screw compressor, the oil also lubricates the rotary screws, which help draw in the air. When the storage tank maxes out, the air compressor turns off, and you can use the pressurized air to power various tools and gear.

To provide the necessary lubrication, an oil air compressor includes a pump, which you can fill with mineral or synthetic oil as you would for a vehicle. Periodically, you must check the oil levels and oil filter to ensure the pump is in working order. Additionally, scheduled oil changes and proper routine maintenance are required for optimal performance.

Any industry that needs pressurized air for its operations can use oiled air compressors so long as contamination is not a concern. A few examples of industries that use these air compressors include automotive, railroad, machinery manufacturing, metal fabrication, and woodworking.

Advantages of an Oil-Flooded Air Compressor

Oil-flooded air compressors offer several advantages for owners and operators. These units feature durable and rugged construction, an important consideration when longevity is a primary concern. Because they can extend the time between air compressor replacements, they could be more cost-effective in the long run. Quiet operation can also make oil-flooded models a better option for industrial or commercial environments where noise prevention is essential.

Minimal heat generation is another advantage of this air compressor type. The diminished risk of overheating lowers the damage potential and enhances safety.

Many companies prefer oil-flooded air compressors because of their relative technical simplicity. Operations that prefer handling equipment upkeep in-house won&#;t need to spend as much time training their team on the machinery. They also won&#;t need to incur the costs of hiring outside labor.

Disadvantages of an Oiled Air Compressor

A disadvantage of lubricated air compressors is that operators and maintenance crews must monitor them regularly to ensure they have sufficient oil. It&#;s also crucial to change the oil and filters at the appropriate intervals. Because they tend to be large, bulky machines, it&#;s often more difficult to move them between locations.

Some owners have concerns about oil contamination, although installing additional filters can often mitigate this issue.

Oil-Free Air Compressor Overview

While an oil-free air compressor works almost identically to an oil air compressor, it does not use oil for lubrication. Instead, it is either constructed to prevent mechanical contact or relies on an option other than oil for lubrication. Most often, users keep their oil-free air compressors operational with water or a Teflon coating.

One difference in how an oil-free air compressor works in comparison to its oil-based alternative is that it moves the air through an initial compressor element to cool it down. There is no lubricating medium to cool the air naturally, so an intercooler is required to keep the temperature low. The second difference is that after compression, the air moves into an aftercooler to cool further. Finally, it can be used to power your equipment.

In industries where contamination is strictly prohibited and can be costly, oil-free air compressors are crucial. For example, food and beverage manufacturing, electronics, and pharmaceutical companies must keep their products pure, and any possibility of physical oil contamination or air contamination from running an oil-flooded air compressor is not allowed.

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Advantages of Oil-Free Air Compressors

The upfront cost of an air compressor matters for many businesses when shopping for these machines. Oil-free models sometimes, but not always, have a lower upfront purchase price depending on model, type, size, and horsepower. But, because oil-free air compressors require less preventative maintenance than oil-flooded compressors, the overall total cost of ownership is often lower.

For many businesses, perhaps the most important oil-free air compressor advantage is their ability to deliver contaminate-free, clean air with no traces of oil. This factor is meaningful to doctors or dentists who need to create a sterile environment for their patients. Or pharmaceutical, electronics, and food and beverage companies that have strict cleanliness standards.

Reduced maintenance requirements are also an attractive feature for companies that may not have the time or labor force for these practices.

The smaller size of these units can be a positive feature for organizations seeking a mobile compressed air solution they can apply in different areas of their facility.

Disadvantages of Oil-Free Air Compressors

Because most oil-free compressors aren&#;t well-suited for heavy-duty environments, they&#;re not the best choice for demanding industrial applications requiring continuous or extended use. Overuse could also require more frequent maintenance and repairs and shorten the equipment&#;s life span.

Depending on the type of oil-free air compressor, the increased noise and heat output can be an issue for organizations where comfort, safety and concentration on job duties are top priorities. Companies may need to invest in powerful industrial cooling equipment to combat the heat. Also keep in mind that oil-free compressors these days have more advanced technologies and design features than previous years, so they&#;re not as loud as they used to be.

Comparing the Key Differences Between Oil and Oil-Free Air Compressors

Oil-Free and oil-flooded air compressors operate differently, meaning you may need one over the other for your applications. As you make comparisons, consider the distinctions between each compressor type. Even with all of the above information, you may need help determining which option is ideal for your business.

Below are a few more aspects of air compressors to help you make the best decision possible:

• Lubrication requirements: As its name suggests, an oil air compressor requires oil to lubricate its moving parts. For example, if you have a rotary screw air compressor with lubricated helical screw pairings, you must change the oil and oil filters to ensure it operates properly. In comparison, oil-free air compressors use a different lubrication medium to operate, eliminating the need for oil.
• Maintenance needs: It likely goes without saying that oil-flooded air compressors require more maintenance. If users neglect to change the oil or check the oil filters or provide routine maintenance, their air compressors will not be as reliable and might not live a long, trouble-free life. Comparatively, oil-free air compressors come with fewer maintenance needs, but they tend to not last as long as a properly maintained lubricated system. Once the frictionless coating starts wearing off in oil-free compressors, you will need to replace your compressor in short order. They also run hotter than lubricated systems.
• Maintenance costs: Because oiled air compressors use oil, they are more expensive to operate. To properly maintain your air compressor, you must have oil on hand so you can change out the old oil based on the manufacturer&#;s maintenance schedule. However, oil air compressors tend to last longer than oil-free air compressors, which can offset the costs required to operate them.
• Contamination risks: If your company is not concerned with oil contamination, an oiled air compressor can be a highly effective and reliable tool for your operations. For businesses where any contamination must be avoided, the oil-free alternative is the best option.
• Noise levels: An oil-lubricated air compressor is quieter because it has the oil to lubricate it. If you are OK with using oil in your applications and would prefer to use a machine with less noise in your work area, choose an oil air compressor. Though they still produce more noise, the good news is modern oil-free air compressors are quieter than previous models.
• Mobility: Oil-free air compressors are lighter in weight than oil-lubricated systems. Part of this is because they don&#;t require additional oil water separators, gallons of oil, oil filters, and other equipment that oil-flooded systems require. But, if you need a system that is mobile, C.H. Reed can help put a package together for you, regardless if you need oil or oil-free.

Ultimately, your selection comes down to your business&#;s unique needs, making it a smart idea to work with a professional team to make the process easier for you.

Shop Compressed Air Equipment From C.H. Reed Today

Depending on your applications and industry, choosing an air compressor can be a crucial decision. Aside from considering the pointers above to guide your choice, you should also make sure to work with a knowledgeable compressed air solutions provider. C.H. Reed&#;s Compressed Air Team has the experience and expertise to help you find the best equipment option so you can accomplish your goals.

For decades, C.H. Reed has worked with industrial companies and manufacturers throughout the Mid-Atlantic to provide them with process and equipment improvements. Whether your business requires compressed air, paint finishing or fluid handling or industrial blowers sales, service, or solutions, we can help you meet your goals.

Get started by browsing our service areas or contacting us with our online form for a quote. We look forward to partnering with you!

Rrumbler said:

Just check the oil every so often,
most have a crankcase capacity of a quart or less,
keep the intake air filtered,
and the filter clean,
and the unit in general;
make sure the belt(s) tension is correct,
and drain condensate regularly.

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EXCELLENT POINTS!!

Please allow me to emphasize the last point: I don't care what size or type of compressor you have - if you don't drain the condensate regularly (drain frequency is directly related to the amount of run time & the humidity level of the incoming air) it will lay in the bottom of your air storage tank and rust a hole in the bottom. Then you can replace the tank.

Yeah, some folks will weld a patch over the hole, but to do it legally (can you say 'law suit' in case it lets go and hurts someone someday?) any welding on a pressurized tank should be done by a certified welder. A friend of mine told me that before he assembled the piping on his compressor, he squirted in a ~1/4 cup of oil into the tank "To prevent it from rusting". Then I reminded him that the oil will simply float on top of any condensate water collected inside and STILL rust out the tank! AND that the oil will travel thru his hoses and he can expect it to foul up any spray painting and sand blasting!!

So when you decide on what air compressor to get, locate it & plumb it in so you can easily drain the condensate. If you only use it for 10 minutes at a time, once a month, you'd likely only need to drain the condensate every 6 months. Even if you only get out a 1/2 spoonful of water, that's enough to rust a hole in the bottom of the steel tank over time.

Good Luck!
RW

EXCELLENT POINTS!!Please allow me to emphasize the last point: I don't care what size or type of compressor you have - if you don't drain the condensate regularly (drain frequency is directly related to the amount of run time & the humidity level of the incoming air) it will lay in the bottom of your air storage tank and rust a hole in the bottom. Then you can replace the tank.Yeah, some folks will weld a patch over the hole, but to do it legally (can you say 'law suit' in case it lets go and hurts someone someday?) any welding on a pressurized tank should be done by a certified welder. A friend of mine told me that before he assembled the piping on his compressor, he squirted in a ~1/4 cup of oil into the tank "To prevent it from rusting". Then I reminded him that the oil will simply float on top of any condensate water collected inside and STILL rust out the tank! AND that the oil will travel thru his hoses and he can expect it to foul up any spray painting and sand blasting!!So when you decide on what air compressor to get, locate it & plumb it in so you can easily drain the condensate. If you only use it for 10 minutes at a time, once a month, you'd likely only need to drain the condensate every 6 months. Even if you only get out a 1/2 spoonful of water, that's enough to rust a hole in the bottom of the steel tank over time.Good Luck!RW

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