Unlike piston compressors, in screw compressors, there are no valves or other mechanical forces that can cause unbalance. This allows a screw compressor to operate at high speeds while combining a large flow rate with small exterior dimensions. The ideal applications of rotary air compressors are continuous, workplace and industrial applications. There are two primary versions, oil-free and oil-injected, with options of fixed speed or variable speed drive operation.

The main benefit of rotary screw compressors is their energy efficiency. But this type of compressor has many other benefits. These include:

• low noise output
• small footprint for point-of-use installations
• no duty cycle
• continuous operation at temperatures of up to 46 degrees C
• low oil-carryover (as little as 3 ppm) in oil-lubricated machines
• zero loss of capacity over time

The installation footprint can be further reduced with “full-feature” variants. Such machines have an integrated refrigerant dryer (dewpoint at compressor output of +4°C).

There are a wide variety of options available in the 2.2-500 kW range of workplace and industrial rotary screw compressors. Recent introductions offer advanced designs such as a vertical, close-coupled configuration. Another distinguishing feature is interior permanent magnet motor drive and inverter systems. Such systems are capable of achieving energy savings of up to 50 percent over conventional fixed speed designs.

Discover our complete range of centrifugal compressors designed for industries and applications that require a large supply of compressed air or gas.

What are centrifugal compressors used for?
Companies that require a large supply of compressed air use our tried and tested centrifugal technology. At the heart of each machine is an individually designed impeller. 

That’s right: each machine is optimized for its power range. Each pressure variant has its own optimized impeller.  These impellers are built to last, which makes the centrifugal compressor a very reliable unit.

Centrifugal compressors are active in various industries: automotive, food, pharma, textile, power, renewable energy, wastewater treatment, the chemical industry and oil and gas.

How to choose between oil-free screw and centrifugal technology?
A very popular answer to this question is to select screw technology for best energy efficiency at lower flows and centrifugal technology for the higher flow demands. To advise the customer on the best technology fit, we have to look at the customer’s application.

It all starts from our customer’s need. For sure, the energy efficiency will play a role in the final selection, yet other parameters like the compressed air demand profile will have to be taken into account as well. Applications that show a fluctuating air demand will benefit more from the wide turndown capabilities of a variable speed driven oil-free screw, while centrifugal units typically would be a better fit on more steady flow demand patterns.

In most cases, the optimum selection is a combination of the 2: An oil-free centrifugal unit taking care of the base load combined with a variable speed driven oil-free screw unit to handle the fluctuating top load. This combo, together with our heat-of-compression dryers, forms a winning team, unique in the compressed air industry, providing ourselves and our customers the guarantee for success.

Benefits of our centrifugal air compressors

• Around-the-clock reliability
• Energy-efficient solution due to multi-speed capability for optimal speed on each stage
• Economical compressor technology
• Noise-reducing canopy
• Highly efficient cooler
• Smallest possible footprint

How does a centrifugal compressor work?
centrifugal working principleZoom in
The working principle of a centrifugal compressor

By adding kinetic energy to air particles and abruptly slowing them down, you build up pressure.

By doing this in several stages, you can go up to 13 bar in lower compression machinery.

And as high as 205 bar in 4-8 stage high compression turbomachinery, also known as multi-stage centrifugal compressors.

1 -stage: up to 2.5 bar
2 -stages: 2.5 bar to 5.5 bar
3 -stages : 6 bar to 13 bar
4-8 stages up to 205 bar
The core of the stage centrifugal compressor consists of 3 elements;

Impeller: The air flow enters the impeller, where the rotating blades increase the kinetic energy of the air

Diffuser: The diffuser manipulates the air flow by gradually slowing down the air velocity and converting the kinetic energy into pressure. 

Volute:  The diffuser discharges in the collector – shaped as a snail shell- also known as the volute. In the volute, the air flow from the diffuser is collected and distributed to an outlet pipe.

What types of centrifugal compressors are there?
We provide standardized or custom-engineered centrifugal compressor solutions.

centrifugal blowers with pressures up to 1.5 bar.
oil-free air centrifugal compressors cores- up to 13 bar
process gas multistage cores up to 205 bar
Within the centrifugal compressors category, 3 main configurations are available:

• An axial multistage is running at a relatively low speed, mostly direct driven by an induction motor. Multiple impellers are lined up axially after each other to gradually build up the pressure.
• Geared turbos are driven by an induction motor rotating at a relatively low speed. The radial impeller(s) are running at a high speed due to a gearbox transmission. Special bearings are required for these high speeds, mostly hydrodynamic bearings are used. Either single or multiple impellers can be installed depending on the required pressure and or flow.
• Highspeed turbos are radial turbos without the presence of any gears. The motor is directly driving the impeller. This means the motor needs to run at high speeds, requiring Permanent Magnet motor technology. To be reliable at these high speeds, magnetic bearings are used to avoid any contact or wear.

1. Oil-free air centrifugal blowers- up to 1.5 bar
In sensitive industrial applications, a reliable supply of oil-free air at lower pressures from 300 mbar (g) to 1.5 bar (g) is needed.
Oil-free air centrifugal blowers need to meet the rigorous standards expected in :

• Wastewater treatment
• Food & Beverage
• Chemicals and Petrochemicals
• Textiles
• General industry
• Power industry
• Mining

Variety of centrifugal blower solutions

There’s more than one configuration we can provide to meet the requirement of your application. No two projects are the same. We realize that the initial investment cost or the total cost of ownership can also be a deciding factor.
Our multistage centrifugal blowers are providing a simple, reliable solution that requires a lower initial investment. Our highly efficient high-speed centrifugal blowers ensure the lowest total cost of ownership.

Newton’s third law states, “to every action, there is an equal and opposite reaction.” It defines what the forces do and how they react. But ever thought why that action occurred in the first place? It is the ‘why’ that gets you closer to the purpose. Knowing what we need and how to achieve it is the basic to thrive. But knowing ‘why’ delivers a better understating of our intent behind those actions.

Purpose Infographic with text
Know our Group’s purpose
Our purpose is to develop industrial ideas that empower our customers to grow and drive society forward; this is how we create a better tomorrow.

Since its inception, this purpose statement has been an integral part of the Group and a guiding force. It continually empowers us to better the way we do things and continue our 150-year-old heritage.

Purpose with an impact
It is a conscious expression of the way an organization intends to evolve and transform itself. Ours expresses a solid intent to usher generations into a better future by engineering ideas that help our customers grow and provide an impetus for societal progress. It has influenced us to integrate sustainability in our strategies and help deliver a positive impact on our people, profits, and the planet.

While it continues to nurture the feeling of belonging in our people, it also tutors us to contemplate the value of what we deliver. It compels us to practice before we preach, think before acting, and put the greater good before self. Earning us sustained loyalty, consistency, and relevance in consumers’ lives, our purpose goes far beyond financial performance.

Now that we have known about the purpose, it is inevitable to find ways to fulfill it. Our 3 core values are connected to it, and here’s how they help fulfill it.

Fulfilling the Purpose through core values:
Innovation, Interaction, and Commitment are our company’s core values. These values define our business culture, guide us in everything we do, and most importantly, fulfill our purpose.

Innovation:

Innovation is a way of everyday life at Atlas Copco. It is deep-rooted in our DNA and doesn’t happen for the sake of it or by chance. It is a result of embracing challenges to deliver the real solution through industrial ideas. Our approach to innovation is about implementing new technologies, encouraging new initiatives, and ground-breaking processes that add to the customers’ growth. Innovation is about fulfilling the purpose of turning great ideas into business-critical benefits.

Interaction:

It answers the question of how do we drive customer growth. We constantly interact with them. Each customer has different needs, and solutions should be designed accordingly. To make sure our customers’ needs are addressed, we collaborate with them at every step. And together, we co-create solutions that not only address their needs but also empower them to innovate. Interaction is about fulfilling the purpose of enabling customer growth and driving society forward through our solutions.

Commitment:

It defines our intent of being a part of a solution for a better tomorrow. We constantly improve our way of working to drive customer growth, add to people’s well-being, and creating a better environment. Through sustainable products and services, we lower energy consumption, reduce carbon footprint and go forth to create a promising future for generations. Commitment is about fulfilling the purpose of bringing value and contributing positively to society’s challenges.

Purpose is the core differentiator and the driving force for an organization. It enables the business to evolve and create a lasting bond with its people. With a strong sense of purpose, it is possible to own loyal customers, highly motivated employees and contribute to the greater good of society.