Types of air compressors for industrial facilities
Air compressors are classified into various categories based on their operating principles, performance, and intended use. Understanding different compressor types helps to select the right equipment for the right application.
A brief history of air compression
Did you know that air compression technology dates back to early metallurgy practices around 3000–1500 B.C.? The earliest compressors were manually operated bellows, later replaced by mechanical systems that introduced automation. By the late 1800s, air compressors became electrically powered, revolutionizing pneumatic energy applications.
Today, continuous advancements in design have led to a wide range of air compression solutions suited for industrial use.
Air compressor types
There are two types of air compressors from which all commercially available air compressors are derived. These are dynamic compression and positive displacement compression.
From the two compressor designs, there are four main air compressor types.
- Axial flow compressors (dynamic)
- Centrifugal compressors (dynamic)
- Piston compressors (positive displacement)
- Rotary compressors (positive displacement)
Each type functions differently and is suited for specific industrial applications.
Dynamic compression type compressors
How do they work? This type of air compressor relies on a phenomenon in fluid dynamics called Bernoulli’s principle. The principle states that as the velocity of a fluid increases, the pressure exerted by that fluid decreases. What that means in practical terms is that a slow-moving fluid exerts more pressure than a fast-moving fluid; they have an inversely proportional relationship.
For example, airplane wings are designed so that air moves faster over the curved top than underneath, creating lower pressure above the wing. The pressure difference generates lift, as gases naturally move from high to low pressure.
An axial flow compression system closely resembles and works like the turbine of a jet engine. Air enters the system through the intake and passes through rows of rotating blades arranged axially as it is compressed (Bernoulli’s principle) and moved along the shaft. The axial flow of air is then discharged at the opposite end of the shaft.
How do they work? In centrifugal compressors the air flows radially outward from the blades and not along a shaft. Air enters the system through an inlet perpendicular to a fast-rotating disc. The disc is lined with curved blades that redirect the air flow along the face of the disc radially outward. The rotating disc increases the speed of air. The air trapped between the curved blades is at a lower pressure relative to air in the inlet. This pressure difference creates compressed air flow and the compressed air is guided towards a discharge chamber.
Key differences
- The axial flow compressor’s advantage is that it produces higher flow rates of compressed air compared to the centrifugal or radial flow design.
- The centrifugal compressor’s advantage is that it produces higher discharge pressures when compared to axial flow compressors, but lower flow rates.
Positive displacement compression type compressors
This type of air compressors rely on a phenomenon in fluid dynamics called Boyle’s law, a principle in fluid dynamics stating that for a fixed mass of gas at constant temperature, pressure and volume are inversely proportional. In other words, as the volume of a gas chamber decreases, the pressure increases.
This partly explains how our lungs work. Our lungs and chest cavity expand when we inhale. Since the size of the chest cavity increases the pressure inside the lungs decreases. And gases flow in the direction of high pressure to low pressure so this facilitates the drawing in of the breath. It works the opposite way when we breathe out.
This principle is the basis for how air is compressed in piston and rotary compressors: by mechanically reducing the space available for the air, the pressure increases, making compression possible.
In a piston compressor, a volume of air is drawn into a chamber through a valve. A piston element retreats from the valve and creates more volume in the chamber, which then causes the pressure in the chamber to decrease (Boyle’s law). Air moves in from the area of high pressure outside the chamber to the area of low pressure within the chamber. Once the piston is fully retreated it begins its advancing stroke which effectively decreases the volume of the chamber. By decreasing the volume of the chamber, it raises the pressure exerted by the air within the chamber (Boyle’s Law). As the piston completes its advancing stroke the compressed air is discharged at high pressure through an exit valve.
With rotary compressor, a volume of air is drawn into a chamber through an inlet or a valve. A rotating element like rotary screws, vanes or lobes sit within the chamber. The rotating elements are designed to move in a way that increases and decreases the available volume in the chamber for the air. For example, in the rotary screw design the air enters the chamber but then finds itself caught between the spiral rotor blades of the screw element. The volume of space between the spiral rotor blades decreases causing pressure to increase (Boyle’s Law). The air is compressed and directed along the grooves of the screw element at high pressure till it is discharged.
Key advantages
- Piston compressors (also know as reciprocating compressors) are more economical, relatively inexpensive, and relatively easy to maintain when compared to rotary compressors. They are best for small projects, machine shops, body shops, tire shops, and small manufacturing facilities.
- Rotary compressors are able to produce a high flow rate continuously while maintaining a relatively small exterior size. Although they are more expensive, they are a better investment in the long term. Considering the total cost of ownership, they provide more uptime, better energy efficiency, higher air quality, longer lifespan, making them more cost-effective.
How to pick the right type of air compressor for your facility
When selecting an air compressor, consider the following:
- What is the application? (E.g., heavy-duty industrial vs. small workshop use)
- What airflow and pressure levels are required? (measured in CFM and PSI [in USA], or m³/min and bar [international])
- What voltage is required? (Ensure compatibility with available power supply and industrial requirements.)
- Is clean, dry air required? (Consider adding dryers and filters)
- What are the operating hours? (Continuous or intermittent use?)
- Are there plans for future expansion? (Scalability considerations)
- Is airflow demand variable? (Variable speed drive compressors can optimize energy savings)
By evaluating these factors, you can select the most efficient and cost-effective air compressor for your facility.
Get help choosing the right compressor
Understanding air compressor types and their applications helps optimize industrial processes, reduce costs, and enhance operational efficiency. Whether you need high-pressure airflow for manufacturing or a steady air supply for smaller applications, choosing the right compressor can significantly impact your facility’s performance.
Still unsure which compressor type suits your application? Contact our experts for tailored advice and explore our full range of air compressors today.
Key considerations when using air compressors
Which industries require air compressors?
Air compressors are integral to a variety of industries and used in various applications, including:
Manufacturing (operating pneumatic tools, assembly lines)
Automotive (spray painting, tire inflation)
Medical (oxygen supply, surgical tools)
Food & Beverage (packaging, aeration, mixing)
Construction (operating jackhammers, drilling equipment)
How much airflow and pressure do tools and equipment need?
Most basic air tools require 70-100 PSI, but specialized industrial tools may need higher pressures.
Additionally, different tools have specific CFM (airflow) requirements, which determine how much air volume is needed to operate efficiently.
Always check the manufacturer’s specifications to ensure compatibility.
What voltage is required to run an air compressor?
The voltage needed depends on the compressor’s size and power requirements. Small compressors used in home applications may run on 110-220V, while larger industrial models may require 680V or even 11,000V.
How to ensure compressed air is free from contaminants?
Contaminants like water, oil, and dirt can compromise air quality. Installing air dryers and filtration systems will help remove moisture and particulates, ensuring clean, dry air for industrial applications.
How regularly do air compressors need servicing?
These are variables that change from one user to the next. Your work will require you to run the air compressor a certain number of hours in a day. We can’t tell what that amount is. With periodic usage in a day an annual service will be enough to cover you. But if your air compressors are running continuously through the day that it’s likely that you will need something like a quarterly service.
How often should you change the oil in an air compressor?
This applies only to Atlas Copco oil-injected type compressors. We recommend that you change the oil every 3 months at a minimum. For some compressors like rotary screw compressors we’d recommend changing oil every 4000-8000 hours of use. This is subject to the recommendation listed in the documentation that comes with the machine.
