How to pick the right rotary screw compressor
When an industrial application calls for a steady supply of quality air, more and more users are turning to rotary screw compressors. Their efficiency, reliability and versatility make them a great choice in these cases. But there are countless applications and many different types of rotary screw air compressors. So which one is the right one for you?
First, let’s look at their benefits: In addition to the efficiency, reliability and versatility, rotary screw air compressors have many other advantages.
Their noise output is low and their physical footprint small. That means you can install them in more places.
Unlike piston compressors, they don’t need cool-down periods. This allows them to operate continuously around the clock - and they do not require a lot of maintenance.
In addition, oil-lubricated rotary screw compressors feature a low oil carry-over of as little as 3 ppm.
Finally, over their expected service life of 10 years or more, you don’t have to worry about a loss of capacity.
Fixed-speed and variable speed rotary screw compressors
The first major distinction is the one between fixed-speed and variable speed rotary screw air compressors. As the name indicates, the former run at a single speed. That makes them a great choice for applications with a steady air demand (and the more steady that demand, the more efficient they are).
Variable speed drive (VSD) compressors, on the other hand, adjust their motor speed to the amount of air that is needed. As a result, they can take their efficiency to another level if the compressed air demand fluctuates.
If that applies to you, you can learn more here about our VSD series.
This article primarily deals with the different types of fixed-speed rotary screw compressors. That means if your air demand is constant, you should read on for important information.
Oil-free and oil-injected rotary screw compressors
Having narrowed your selection to fixed-speed compressors, the next step is to choose between oil-free or oil-injected models.
The difference is that the latter introduces a new contaminant into the compression process. Therefore, you would pick an oil-free compressor if the presence of oil vapors matters – for example if your industry is subject to air purity standards. This includes the pharmaceutical industry, the food and beverage sector and semiconductor manufacturing.
Here, oil-free technology is a better alternative than using an oil-injected model and then filtering out the contaminant.
If air quality is less important, for example if you need the compressor to power pneumatic tools, then an oil-injected model will generally suffice.
Two drive types, lots of benefits
Atlas Copco offers its fixed-speed rotary screw compressors with two types of drives. Depending on your application, each of them has different advantages.
-Belt drive: Fixed-speed rotary screw compressors with belt drives are very robust. They are the least expensive and are easy to install, operate and maintain. For all of these reasons, they are a popular choice for smaller operations.
-Gear drive: A gear drive makes a compressor quieter. That means you can install it in more places without violating noise standards. Their initial investment cost is a little higher. However, because they are more efficient and maintenance free, rotary screw compressors with gears are less expensive to operate. This will allow you to quickly recoup that higher cost.
Getting your compressor size right
No matter which type of compressor you choose, it is very important that you get its size right. If the unit is too small, it may not get the job done. If it is too large, you will waste a lot of valuable energy.
However, rotary screw compressors are a good deal with lots of benefits at any size. That starts with the smallest unit from Atlas Copco – the G 2-7 range. Compared to piston air compressors, which are traditionally used by operations with a limited compressed air demand, they offer many advantages. First and foremost, they are more efficient, which reduces your costs and environmental footprint.
Because they can run around the clock, they can handle an increased demand better. Finally, fixed-speed rotary screw compressor lower the oil content in your compressed air system.
And the larger your compressor gets, the more you can save down the road.
A complete offer
Atlas Copco offers a complete range of oil-injected fixed-speed compressors for different types of users with different priorities:
- G: the robust, reliable option with the lowest purchase price for professional users. If you are used to working with a piston in your workshop, there is a good chance the G could be a more efficient, quiet and flexible alternative.
- GA: outstanding performance and dependability in demanding industrial environments where issues like efficiency and connectivity are not top priorities. If you are looking for a best-in-class compressor with the trusted Atlas Copco quality but no extras, the GA will a good solution.
- GA+: Atlas Copco’s premium fixed-speed rotary screw compressor, offering industry-leading performance, even in harsh environments. It features a maintenance-free drive system that is protected against dirt and dust. It is significantly more energy efficient than the G and GA series and offers more connectivity options.
What is a rotary screw compressor?
Our experts can walk you through the compressor selection process step-step-by-step. They can also help you identify any air quality requirements for your industry.
Our experts can walk you through the compressor selection process step-step-by-step. They can also help you identify any air quality requirements for your industry.