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

06 May.,2024

 

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.

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!

Is an Oil-Free Compressor Really Better? - Oil-Lubricated ...

Is an Oil-Free Compressor Really Better?

Oil-Lubricated Vs Oil-Free Air Compressors

By Melissa C.


Air Compressor Expert

Whether you're a homeowner, contractor, or mechanic, at some point you've probably debated
oil-lubricated
vs.
oil-free air compressors

and wondered to yourself, "What's the big difference?"


New information and technology seem to change every year, and while the 'oil vs. oil-free' question persists, the arguments don't always keep up with these developments.


So, let's separate fact from fiction and get to the bottom of the debate. The next time your buddy wants to argue what makes the best compressor, you'll have ammunition about both.




The Oil vs. Oil-Free Conundrum

The differences that separated oil-lubricated and oil-free compressors years ago aren't the same today, even though the terminology hasn't changed that much. However, there seems to be unnecessary confusion because some people compare all different types of compressors at once when in fact the debate, at its core, is really about the most common type.


For argument's sake, we're not talking about compressors used for heavy-duty or commercial industry applications because those compressors have specific demands that 2-stage,
rotary screw, or scroll compressors deliver; we're simply talking about the most common types of compressors encountered every day: reciprocating single-stage piston air compressors.

Contact us to discuss your requirements of chinese piston compressor factory. Our experienced sales team can help you identify the options that best suit your needs.


How Air Compressors are Lubricated

All compressors, regardless of their type, need a method of lubrication to moderate heat, friction, and the wear-down
of the pump and critical components. The biggest difference, however, is whether the lube comes from oil or a special material coating.


Oil-Free Lubrication

Oilless compressors do not use oil for lubricating. Instead, their wearable parts are coated in special friction-reducing chemicals and are designed to be self-lubricating for the life of the compressor.


Splash Lubrication

The most common type used, splash lubrication is just how it sounds. These compressors use rotating dippers (think of small flat spoons) attached to the bottom of connecting rods that swing and splash oil up from the reservoir against the internal moving parts.




Is Oil or Oil-Free Better?

Now you know the basics of each type, we can now answer the question, "How does oil-free compare to oiled and which is better?"
You've undoubtedly heard some myths, so let's debunk them and explain what they mean to you, the user.


Myth #1: Oil Lubricated Compressors Last Longer

The chief argument these days is that oil-free compressors can't match the longevity and dependability of oil lubed compressors and therefore don't offer the same value. Routine maintenance and regular oiling tended to make oiled compressors more durable and have a longer lifespan than the first versions of oil-free machines. Although that might've been the case before oil-free technology took off, it just isn't true anymore. Today's oilless compressors run cooler and come better protected than ever before.


Myth #2: Oil-Free Compressors Are a Lot LOUDER

Again, the oil-free compressors of yesteryear were unquestionably loud, but today's designs feature direct-drive, dual-piston (duplex) pumps and advanced sound-reducing technologies that make oilless compressors much softer than their oiled, shouty brethren.


Myth #3: Oil Lubed Compressors Run Cooler and Withstand Extreme Conditions

Actually, the dual-pump designs of oil-free compressors allow them to achieve the desired CFM/PSI in half the revolutions (RPM). They also use heat-dissipating aluminum cylinders to run cooler. In fact, oilless compressors are preferred in extreme cold because there's no worry about the oil turning to sludge. On the other hand, oiled compressors may be desired if working in extreme heat and humidity, because they can dissipate heat more quickly in a given duty cycle and resist rust build-up.




Advantages/Disadvantages of Both

Oiled Compressors

An industry-standard among professionals, oiled stationary compressors are typically installed in a shop where high pressure and volume keep all of the tools running all day, every day and stand up to years of abuse if properly maintained.

  • Suited to professional applications
  • Higher RPMs mean higher PSI/CFM ratings
  • Heavier, not as portable
  • Requires routine maintenance
  • Can be used in hot climates
  • Oil contaminates the air


Oil-Free Compressors
These types of pumps (duplex) operate at lower RPM, reducing the noise, heat, and friction which extends the pump's life cycle and,
mixed with better castings/exacting tolerances and better frictionless coatings, make oil-free a great choice in many applications.

  • Cleaner, drier air
  • Lighter weight, more portable
  • Maintenance free, no oiling needed
  • No oil filters required
  • Can be used in cold weather
  • Quieter, more efficient



How to Pick One Over the Other

The first step with any piece of equipment is to consider how it will be used before evaluating other items such as cost. We're so used to the oil-less debate only referring to small, portable compressors that it's easy to forget that they're also available as stationary, single-stage piston compressors as well.


Let's take a look at the differences between oil and oil-free stationary and portable compressors in more detail.


Oil vs. Oiless Comparison

20 Gal. Poratble

Oil Lubricated

20 Gal. Portable

Oil-Free

60 Gal. Stationary

Oil Lubricated

60 Gal. Stationary

Oil-Free

Weight & Pump Drive Type 200 lbs
Belt Drive 110 lbs
Direct Drive 261 lbs
Belt Drive 213 lbs
Direct Drive Pump Material Cast Iron Aluminum Aluminum
(Cast Iron Sleeve) Aluminum Max PSI 135 PSI 125 PSI 130 PSI 120 PSI Max CFM 5.2 @ 90 PSI 5.8 @ 90 PSI 12.8 @100 PSI 10.6 @ 90 PSI Noise Rating 80 dBA 41 dBA N/A 75 dBA


The Bottom Line

So, if you're a DIY homeowner or contractor looking for a portable compressor, to carry around the job site, then an oil-free option may be desirable for its lighter weight and ability to use them in any orientation.


If you're a commercial business looking for a stationary compressor to power high PSI/CFM pneumatic tools, you may opt for an oiled compressor. Or, if you're concerned with noise, air purity, changing filters and maintenance, then an oil-free stationary compressor would be ideal.


The bottom line is to get the air compressor
you
need for the job
you
need to perform; it'll pay you back to listen to your gut and get the facts. If you ever need help deciding, we're here to help.



NEXT:
How to Pick the Perfect Air Compressor

By Melissa C.


Air Compressor Expert

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