An air compressor is a device that takes in air, compresses it, and then pumps the compressed air out at high pressure. Any gas can be compressed as long as there are some means of containing the pressurized gas. Discover how does an air compressor work in the following article, plus learn about the different types of air compressors.
There are three main types of air compressors: reciprocating, centrifugal, and rotary. Each function differently, and each has its own unique set of benefits and drawbacks. In this article, we’ll take a closer look at how each type of compressor works and what situations they’re best suited for.
Different types of compressors: rotary, reciprocating, centrifugal
Different types of compressors have different benefits and drawbacks. Rotary compressors are less efficient but can handle a large amount of air. Reciprocating compressors are simple but relatively inefficient.
Centrifugal compressors are the most common type and are very efficient. Each compressor has its own unique set of benefits and drawbacks, making it better suited for certain applications.
This is the most common type of compressor used in small-scale commercial applications. The main components consist of a piston cylinder assembly, valves, and an electric motor. As the name implies, this compressor moves the air by use of pistons that go up and down inside cylinders.
They typically use a single reciprocating piston to drive the compression process. Their operation can be compared to that of a diesel engine, or a positive displacement pump depending on the direction of gas flow.
Two types of reciprocating compressors: single-acting and double-acting.
- Single-acting cylinders are used mainly in low pressure applications, since the “pumping” of air is done by atmospheric pressure on one side of the piston while it descends into the cylinder.
- Double-acting cylinder both pushes air out and sucks it in, allowing for more powerful output pressures.
The piston cylinder assembly consists of the piston, piston rod, cylinder, valves (usually one inlet valve and one outlet valve), preload assembly, and base.
Centrifugal compressors use a spinning impeller to draw in air and force it into a chamber.
This design is much more efficient than reciprocating compressors, making them the most common type of compressor used today. They can be found in both small and large applications, from home air conditioners to industrial-sized turbines.
The main parts of a centrifugal compressor include a casing, impeller blades, diffuser vanes, and center hub. The air enters the front of the compressor and is drawn into the impeller blades as they spin.
The impeller forces this air at high velocity through diffusers which redirects it to be forced between the casing wall and impeller blades.
The diffuser vanes help further transfer the maximum amount of energy into the air by increasing turbulence and reducing velocity, while also allowing for superior flow.
In a rotary compressor, air is drawn in from one side of the vanes and moves radially across the vane. In order to get the maximum compression effect, this must happen simultaneously on both sides of the vane.
The chambers which house these vanes are similar to that of a centrifugal compressor, except that they have intake and discharge ports on each side of the vanes so air can flow through each chamber simultaneously.
The high velocity of the air moving across these vanes causes it to slow down, which also reduces turbulence and noise that would otherwise be created by this process.
When the compressed air reaches a predetermined point, it is forced out into an output manifold.
Here are the most common types of commercial rotary compressors in use today:
Screw Type Compressors
Scroll Type Compressors
Vane Type Compressors
Lobe Type Compressors
Rotary Rotors can actually be used as a part of many other types of rotary compressor mechanisms as well. Rotary Rotors are often used in combination with either Rotary Scroll or Rotary Vane types of Rotary Compressor. Rotary Rotor types vary depending on the intended application, whether it is for home appliances, industrial heating and cooling, refrigeration, air conditioning etc. Rotary Rotors can be single stage which usually operate at very high speed.
How does a rotary compressor work
The air is drawn into the compressor by a rotating impeller, which forces it into a chamber. There, it’s compressed by a stationary piston before being pumped out at high pressure. This process is repeated over and over again to create the desired level of compression.
Rotary compressors are often used in high-power applications due to their ability to handle large amounts of air, while reciprocating compressors are more commonly found in small air tanks and refrigeration units. Centrifugal compressors are the most popular choice for home air conditioners and other small appliances.
Rotary compressors are similar to centrifugal compressors but use a rotary vane instead of an impeller to move air into the chamber.
This makes them less efficient but allows for greater flexibility when it comes to compression ratios. Rotary compressors are typically used in high-power applications due to their ability to handle large amounts of air.
How does a reciprocating compressor work
The air is drawn in through an intake, where it’s then compressed and pushed out the discharge valve. A piston moves back and forth to compress the air. This process happens continuously as long as there is power supplied to the unit. Reciprocating compressors are simple but relatively inefficient, making them a less popular choice for modern applications.
They can still be found in low-power applications such as small air tanks and refrigeration units.
Reciprocating compressors are reciprocating machines with two heavy, rigidly connected masses (called pistons) moving in opposite directions. The reciprocating compressor is one of the most common and time-tested power units in existence, and reciprocating compressors offer the following features:
- High Dynamic range.
- Power capacity relative to size and weight.
- Long wear life compared to most other power units.
How does a centrifugal compressor work
Centrifugal compressors work by using a spinning impeller to draw in air and force it into a chamber. This design is much more efficient than reciprocating compressors, making them the most common type of compressor used today. They can be found in both small and large applications, from home air conditioners to industrial-sized turbines.
Once the air passes through the diffuser vanes, it enters a volute (sometimes called a scroll) which is tapered in order to allow more area on the inside of the chamber while keeping a constant cross-section on the outside.
The high velocity air becomes pressurized as it is forced through this area, which also helps to increase pressure and improve efficiency even more than it already was with the diffuser vanes. Finally, the air vents out at the back of the compressor into an output manifold or pipe.
Compressor Highlights & Low Lights
- Reciprocating compressors work by using a piston to move air in and out of a chamber. This design is simple but relatively inefficient, which is why they’re not commonly used anymore. However, they can still be found in some low-power applications such as small air tanks and refrigeration units.
- They have established themselves in applications that require high volume capacity at moderate pressure ranges, but reciprocating compressors are not ideal for all applications.
- The reciprocating compressor has many advantages over other power units. It’s reciprocating nature produces high power capacity relative to size and weight, making reciprocating compressors ideal for large-volume applications where the reciprocating compressor’s reciprocating motion is converted to rotary motion.
- Simple but relatively inefficient, making them a less popular choice for modern applications. They can still be found in low-power applications such as small air tanks and refrigeration units.
- The spinning impeller design is much more efficient than reciprocating compressors, making them the most common type of compressor used today. They can be found in both small and large applications, from home air conditioners to industrial-sized turbines.
- The advantages of centrifugal compressors include their increased efficiency, resulting in lower costs over time; however, they tend to be more expensive than reciprocating or rotary compression systems due to their complex design.
- Centrifugal compressors do require lubricants during operation which can increase wear on parts if not cleaned regularly.
- Similar to centrifugal compressors but use a rotary vane instead of an impeller to move air into the chamber. This makes them less efficient but allows for greater flexibility when it comes to compression ratios.
- Rotary compressors are typically used in high-power applications due to their ability to handle large amounts of air.
- Rotary compressors boast high horsepower capabilities at a low cost per cubic foot of compressed air but have higher maintenance requirements that may limit them from being used in some applications where downtime is a concern.
Using the right air compressor for your needs is important. Be sure to check that it can handle the type of construction or industrial work you need, and be mindful of its power requirements when choosing a location to use it in. As long as you’ve done your research, finding an air compressor should be easy with our guide!
We hope the information in this blog post helps you identify which type of air compressor best suits your needs. If you have any questions, please contact us. Our knowledgeable staff are happy to answer them for you!