Oil-free vs Oil-injected Air Compressors: What Is Right for You?

In the world of air compressors, choosing between oil-free and oil-lubricated models can be confusing and daunting.

Both types have unique benefits and limitations, and making the right choice depends on your industry or specific application needs and requirements.

This blog will help you understand the critical differences between oil-free and oil-injected air compressors and provide you with the information you need to make an informed decision.

Whether you're a professional mechanic or a manufacturing plant manager, this article will give you a better understanding of the pros and cons of each type and help you determine which one is right for your industry application.

What Is an Oil Free Scroll Compressor?

A scroll compressor is also referred to as a spiral compressor, a scroll pump or a scroll vacuum pump. The rotary spiral scroll design creates a continual compressed air flow over multiple stages and there is no need for oil lubrication.

Does That Mean That Oil-Free Has No Oil At All?

Oil-free air compressors do not contain oil in their element or anywhere in the path of the process air being compressed. However, they still use oil for the bearings and gear in the mechanical drive system to ensure smooth operation.

The gearbox is a crucial component of the air compressor, driving the compressor elements with the help of a drive motor. Regular maintenance checks are essential to keep the gearbox lubricated and functioning smoothly, as replacing these components can be costly. The oil in the gearbox lubricates the internal gears, bearings, and other parts. It is cooled and filtered before being re-circulated, ensuring efficient cooling of the elements and gearbox parts.

Despite the presence of oil in the mechanical system, the oil is entirely absent in the compressed air circuit. This separation guarantees the highest air quality for your application. It also simplifies day-to-day maintenance activities by reducing service interventions and improving efficiency by avoiding unnecessary pressure drops in the line filters.

Oil-Free vs. Oil-Injected Air Compressors: Major Differences

The Presence of Oil

Oil-free air compressors do not have any oil mixed in the compression chamber. They rely on Teflon-coated screw elements and two-stage compression (using two elements) to generate compressed air without compromising air quality.

In contrast, oil-injected air compressors use oil to lubricate the moving parts and ensure smooth operation. The oil also helps to cool the element, acts as a sealant, and removes contaminants from the air stream.

As its name suggests, an oil air compressor requires oil to lubricate its moving parts. For instance, in a rotary screw air compressor with lubricated helical screw pairings, regular oil and oil filter changes are necessary to maintain proper operation. In contrast, oil-free air compressors utilize alternative lubrication methods, eliminating the requirement for oil altogether.

Maintenance

Maintenance is a significant factor when choosing the type of air compressor. Oil-free compressors generally require less maintenance, as there is no need to change large quantities of oil or separators, oil filters etc. In contrast, oil-lubricated compressors require more maintenance, including frequent oil changes and cleaning of the lubrication system.

Comparatively, oil-free scroil 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.

Application

Oil-lubricated compressors are typically used in industries where air quality is not a primary concern, such as cement, metal, plastic, or general manufacturing. In contrast, oil-free compressors are better suited for applications where clean, oil-free air is essential.

Oil-Free Vs. Oil Air Compressors: What Are The Suitable Industries?

Industries using oil-free air compressors:

Food and beverage industry

Pharmaceutical industry

Electronics manufacturing

Chemical and petrochemical industry

Fertilizer manufacturing

Aerospace and defense

Industries using oil-lubricated air compressors:

Automotive repair shops

Construction sites

General manufacturing

Mining indusry

Oil and gas industry

Oil-Free Vs. Oil-Injected Air Compressors: Which One Is Right for You?

Choosing between oil-free and oil-lubricated air compressors can be difficult, as both types have unique benefits and drawbacks. When deciding which one is right for you, it's essential to consider several factors, including the specific needs of your application, the type of work you will be performing, and your budget.

An oil-free compressor may be the best choice for applications where clean, oil-free air is a top priority, such as in the food and beverage industry, pharmaceuticals, and electronics manufacturing. In addition to Class 0 air quality benefits, oil-free compressors are also chosen for lower maintenance and operating energy costs, as well as reduced environmental impact.

On the other hand, an oil-lubricated compressor may be more suitable for general manufacturing where initial cost is a primary consideration in the selection process.

Conclusion

In conclusion, selecting the right air compressor for your business and industry is crucial for ensuring efficiency, performance, and longevity. With the diverse options available in both oil-free and oil-lubricated air compressors, making the best choice can be challenging.