Different Types of Air Compressors and Their Uses
Air compressors are widely used in manufacturing, construction, machine-working generally, and elsewhere across multiple industries. They’re used to compress air, gasses, and occasionally fluids. Of these, fluid is rarely compressed because, broadly speaking, it doesn’t tend to compress to a satisfactory compression ratio.
Some compressors will compress gasses or air at a certain pressure level or are for specialist applications. For example, diaphragm compressors deliver low-volume, compressed air that’s very clean for laboratories and healthcare sectors. Rotary lobe compressors are another type that produces a low pressure at high volume, ideal for positive displacement and centrifugal blowers.
Air compressors needing to deliver a steady flow of high-pressure, high-volume compressed air must be fit for this task. Not every compressor meets this need. Internally, air compressors are split across two categories: positive displacement and dynamic displacement types. Below, we discuss 4 of the air compressor types that fit into either one of these categories.
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Different Types of Air Compressors
Air compressors come in two main types: positive displacement and dynamic displacement, each suited to specific applications.
Positive Displacement Compressors
These compressors trap air in a chamber, compress it, and then discharge the air. Common types include:
- Reciprocating Compressors: Often used for home projects and light industrial tasks, these compressors can be single or multi-stage for higher pressure needs.
- Rotary Screw Compressors: Ideal for continuous industrial use, these oil-lubricated compressors provide reliable airflow over extended periods.
- Scroll Compressors: Known for their quiet operation and production of high-quality compressed air, scroll compressors are perfect for sensitive environments such as laboratories.
Dynamic Compressors
Dynamic compressors, such as centrifugal compressors, work by accelerating air to high speeds. These are typically used in large-scale industrial applications where high volumes of air are required.
Choosing the Right Compressor
Selecting the right compressor depends on your specific requirements. Positive displacement compressors are ideal for providing steady airflow, while dynamic compressors are better suited to high-volume tasks.
Positive Displacement Compressors
The positive displacement compressor category includes both reciprocating compressors and rotary screw types.
Both types have a cavity where the air is stored, which is gradually compressed down to increase the air pressure level. While exactly how this is performed differs between positive displacement compressor types, the outcome is similar.
1. Reciprocating Air Compressors
Reciprocating compressors are sometimes deployed on smaller construction sites, but more often are put to use on home projects, such as when adding a garage or a third bedroom to an existing property. These compressors are also known as piston compressors. The air generated by these units can operate power tools that rely on compressed airflow to work and/or avoid overheating.
These types of compressors produce pressured air through a single-stage or multiple-stage operation. The main compressed air mechanism is a piston within a cylinder that provides compression and moves the air into a restricted area.
This mechanism is more complex than others. It requires oil to keep it operating smoothly and avoid overheating. The multi-stage versions produce higher air pressure levels than a single stage is capable of. However, reciprocating compressors aren’t capable of providing continuous air pressure for workplace applications that require it.
2. Rotary Screw Air Compressors
The Rotary Screw compressor is a popular way to compress air. Indeed, many of the air compressors in the Atlas Copco (that we supply across all of our Service locations) product range incorporate a rotary screw design within their internal structure. Depending on the machine itself, it may operate without using oil or benefit from lubricating oil.
Two rotors (screws) are positioned in opposite directions to create a positive pressure build-up from the air contained inside. The generated heat is typically well managed, allowing for non-stop operations or individual projects lasting several hours at a time. This type of air compressor uses powerful motors with a capacity of several hundred horsepower, where necessary.
Many Atlas Copco variable speed drive air compressors that Anglian Compressors supply and install incorporate a rotary screw design.
3. Rotary Vane Compressors
A rotary vane compressor is a type of positive displacement compressor that uses a rotating rotor with sliding vanes to compress air. Imagine a cylinder with slots where vanes can slide in and out. As the rotor spins, centrifugal force pushes the vanes outward, creating chambers that trap air. The chambers get smaller as the rotor turns, squeezing the air and increasing its pressure.
These compressors are known for their quiet operation, compact size, and relatively simple design. They come in both oil-lubricated and oil-free versions, offering flexibility depending on your air quality needs. Oil-lubricated models are generally more durable and efficient, but they may introduce a small amount of oil into the compressed air, requiring filtration if clean air is essential. Oil-free versions eliminate this concern, making them ideal for applications like food processing or pharmaceuticals.
Rotary vane compressors are a good fit for smaller businesses and workshops with moderate air demands. They’re not the most powerful or efficient option for large-scale industrial use, but they offer a reliable and cost-effective solution for many applications. If you need quiet, oil-free compressed air and don’t have massive air volume requirements, a rotary vane compressor might be right for you.
4. Rotary Scroll Compressors
A rotary scroll compressor is another type of positive displacement compressor that uses two spiral-shaped scrolls to compress air. One scroll is fixed, while the other orbits around it without rotating. This creates pockets of air that gradually decrease in volume as the moving scroll orbits, compressing the air trapped inside.
These compressors are prized for their quiet and vibration-free operation, making them ideal for noise-sensitive environments like hospitals and laboratories. They are also inherently oil-free, producing clean air suitable for applications where contamination is a concern. Scroll compressors are known for their efficiency, particularly at lower pressures, and their simple design with few moving parts reduces maintenance requirements.
Rotary scroll compressors are typically more expensive than other types due to their precise engineering and the use of high-quality materials. They are best suited for applications that require clean, dry, and quiet compressed air but have relatively low to moderate air demand. If you prioritize air quality and low noise levels, and your air requirements are not excessively high, a rotary scroll compressor might be a valuable investment for your operation.
Dynamic Displacement Compressors
There are multiple types of dynamic compressors. The most popular are the Axial and the Centrifugal compressors.
Dynamic compressors aim to produce kinetic energy. The compressed air process is often implemented to produce pressure, to drive engine horsepower, rather than to output compressed air for manufacturing, use with power tools, etc.
With dynamic compressors, fan blades spin and suck in air from the surrounding area. This is captured and retained in a small space to create positive pressure. Ultimately, the horsepower created from these types of compressors is impressive, but that comes at a higher cost.
1. Axial Air Compressors
People working in construction may have never heard of Axial compressors. This is because they’re considerably more expensive, sizeable, and best suited for larger applications such as ships, or the aerospace industry where bigger capacities matter.
Axial compressors are highly efficient but aren’t as practical on the manufacturing or production floor.
2. Centrifugal Air Compressors
The Centrifugal compressor relies on pulling ambient air into its diffuser as a way to create energy. Room temperature – or cooler air, is required for input. The internal air compression goes through multiple stages, with each one increasing the pressure achieved.
Relative to their size, these compressors use a high amount of horsepower for their installed footprint. Some do not require oil to operate, while others do. They’re mostly found in manufacturing plants, such as chemical or steel producers.
Picking the Most Appropriate Air Compressor
Choosing the right air compressor depends on factors such as air demand, efficiency, and available space.
Air Demand and Types
Understanding the different types of air compressors is crucial for meeting your air needs. Multi-stage compressors are suited to high-pressure tasks, while single-stage options are ideal for smaller projects. Industrial air compressors are typically required for heavy-duty applications, whereas scroll compressors are more appropriate for quieter, cleaner operations.
Energy Efficiency
Variable-speed compressors are more energy-efficient, adjusting output based on demand. In contrast, fixed-speed compressors run continuously, leading to higher costs if air usage fluctuates.
Space and Installation
Air compressors come in a variety of sizes. Rotary screw compressors are compact and can fit into smaller spaces, while larger models, like centrifugal compressors, require more room for installation and proper ventilation.
Air Quality and Maintenance
Oil-free rotary screw compressors are ideal for applications requiring clean air, such as food processing, while oil-lubricated air compressors offer greater efficiency but require more maintenance.
Cost vs. Performance
Selecting an air compressor that balances cost and performance is essential. Reciprocating compressors are cost-effective for smaller operations, while higher-end models, such as centrifugal compressors, are better suited to large-scale industrial use.
Ready to Take Control of Your Compressed Air System?
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Need help navigating the world of air compressor monitoring? Anglian Compressors is here to guide you every step of the way.
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Don’t let your compressed air system operate in the dark. Get in touch with Anglian Compressors today, and let us help you gain control, optimize performance, and breathe easy knowing your equipment is in capable hands.
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FAQ
What are the main types of air compressors, and how do they work?
Air compressors come in two main types: positive displacement and dynamic. Positive displacement compressors, such as reciprocating and scroll air compressors, operate by trapping air in a chamber, compressing it, and then discharging the compressed air. Dynamic compressors, like centrifugal compressors, use high-speed rotors to draw in air and convert velocity into pressure, efficiently producing large volumes of compressed air.
What factors should I consider when choosing an air compressor?
When choosing an air compressor, consider your specific air requirements, such as whether you need a lubricated air compressor for industrial tasks or an oil-free model for clean air applications. You should also consider the variety of compressors available, including fixed-speed compressors for consistent use or variable-speed compressors for improved energy efficiency. Selecting the right compressor ensures it can meet your air demands effectively.
What are the advantages of using scroll air compressors?
Scroll air compressors are a type of positive displacement compressor, valued for their quiet operation and ability to produce high-quality compressed air. They are ideal for applications where noise reduction and clean, oil-free air are crucial, such as in healthcare or laboratories. Air is drawn into the compressor, compressed between two spiral-shaped scrolls, and then discharged with minimal vibration.