How Do Scroll Air Compressors Operate and Why Use One?
Air compressors are a functional and important part of the manufacturing industry, so there are various air compression technologies available to meet the needs of just about any application. Because scroll air compressors are available as both oil-lubricated and oil-free air compressors, they are a versatile option, but how do you know if scroll compressor technology is the right choice for your operation?
This blog hopes to answer that question by discussing the basic operating principle of scroll air compressors, the differences between scroll compressors and rotary screw compressors (which are also available in oil-lubricated and oil-free models) and a general comparison of oil vs. oil-free compressors to help you decide if scroll air compressors and/or oil-free technologies are the way to go.
What is a Scroll Compressor?
Scroll compressors, also called spiral compressors and scroll pumps, work via positive displacement technology. Scroll air compressors feature two spiral shaped scroll elements – one of which is a stationary scroll and the other a motor-driven orbital scroll. The orbital scroll, driven by a crankshaft, moves around the stationary scroll to create suction that draws air in from the inlet at the top of the housing. This air is captured in pockets between the scrolls and is gradually compressed as it is moved toward the center of the compression chamber. The compressed air is then discharged from the outlet and stored until it is ready for use.
The simple design and operating technology of the scroll compressor means it is energy efficient, low maintenance, compact and nearly noise free when compared to other air compression technologies.
Available as an oil-free option, scroll air compressors are one of the compressor types that are considered for use in sensitive industries, such as food and beverage manufacturing, automotive painting, chemical processing, medical device and electronics manufacturing and pharmaceutical production.
Rotary vs Scroll Compressor
Because both rotary screw and scroll air compressors are available as oiled and oil-free technologies, when specifying an air compressor, the choice often comes down to rotary vs scroll compressors, so we will explain the main differences between the two.
While the scroll compressor operates via one fixed scroll and one that orbits around it to compress the air, the design of a rotary screw compressor consists of a male and female motor, which mesh closely without touching. As they rotate, the helical screws decrease the volume between them, compressing the air in the chamber and forcing it toward the center of the rotors. The treated air exits through a central discharge port at the end of the rotors.
Aside from design differences, rotary screw and scroll compressors can be compared by their operational pros and cons:
| Scroll compressors | Rotary compressors |
| Because scroll compressors are designed with efficiency in mind, they will automatically shut down compressor pumps when they are not in use, which saves electricity and extends the useful life of the unit. On the flip side, this means they do not provide large volumes of air so they may not be suitable for high-volume or continuous-use applications. Scroll compressors offer a simple design that is low maintenance, highly reliable, compact and relatively quiet. | These compressors offer a wide capacity range so they can efficiently produce small or large volumes of air, which makes them suitable for a range of applications. In addition, they offer continuous operation, making them reliable in operations that demand continuous airflow. |
Oil vs Oil-Free Compressors
When choosing between rotary screw and scroll air compressor technologies, you may be given the option of selecting either an oiled or oil-free air compressor. So, here we will discuss the advantages of oil-free technologies and compare the two options.
Oil-free air compressors are required in sensitive applications, such as food and beverage production, pharmaceutical processing, medical device and electronics manufacturing and automotive painting, that demand the highest quality air to ensure that the finished product is contamination free. But there are benefits to using oil-free air compressors for other industries, as well.
Oil-free air compressors offer several advantages, including:
- Reduced product contamination: Oil-free air compressors eliminate the possibility of oil contaminating sensitive products or operations.
- Low maintenance: Because they are oil free, this type of compressor does not require routine oil changes, oil disposal or changes of oil filters, which reduces maintenance requirements and costs.
- Environmentally friendly: As oil-free air compressors do not require oil disposal and do not emit oil contaminants, they are a more sustainable and environmentally friendly choice.
While there are advantages to going oil free, there are also some drawbacks when comparing traditional and oil-free air compressors, so we will compare oil vs oil-free compressors by several factors to help you decide if oil-free compressor technology is right for your application.
- Footprint: Oil-free air compressors are usually smaller and more compact than oiled versions as they do not need to include space for oil.
- Cost: Oil-free air compressors usually have a higher initial price tag than traditional technologies, but they require less preventive maintenance and lower maintenance-related costs as they do not require new oil or filters or oil disposal costs.
- Environmental risks: Oiled compressors may leak and leach oil into the environment, which is not favorable in today’s sustainability-based corporate environment. The lack of oil in oil-free air compressors reduces the risk of contamination of products and the environment and can help reduce a facility’s carbon footprint.
- Efficiency: Oiled air compressors run more efficiently than oil-free air compressors as they are lubricated, which allows the internals to run more smoothly so the compressor doesn’t have to work as hard, making them more energy efficient.
The choice between an oiled or oil-free air compressor or a rotary screw or scroll compressor can be a confusing one, but it is essential to choose the technology that is most suited to the application and the industry. The experts at JHFOSTER are standing by to provide more details on the various technologies to ensure that the selected air compressor is the right one for your operation.