Air compressors are essential tools used in construction sites and plants. They are used to power any pneumatic or electrical tool that might be used. They pressurize air from the environment and then pump it into the tool.
There are multiple types of air compressors. However, in this article, we will be discussing the four primary or main types of air compressors.
Air compressors are divided into categories according to many aspects like their:
- Service pressure
- Drive types
- Lubrication method
- Cooling method
- Number of stages
Two Main Categories:
However, these are not the aspects that we will be discussing. We will classify them according to their principle of operation. Air compressors’ principle of operation divides them into two main categories. They are:
- Dynamic Displacement Air Compressors
- Positive Displacement Air Compressors
We will discuss each type of them separately.
1. Dynamic Displacement
They work at a constant pressure level and are categorized based on their design, whether it is axial or radial. Unlike positive displacement air compressors, external conditions like inlet temperature impact the compressor’s performance.
For dynamic compression to start, the air is drawn between blades on a rapidly rotating compression impeller while it accelerates to a high velocity. While gas is discharged through a diffuser and the kinetic energy is transformed into static pressure.
The direction of the gas flow determines whether this is an axial or radial dynamic displacement air compressor. These compressors are capable of producing massive horsepower, and this is why they are referred to as turbo compressors.
2. Positive Displacement
They work by alternating pressure, unlike dynamic compressors. They also work with a constant flow regardless of outlet pressure. For them to work, the air is drawn into chambers; these chambers are closed from one side (inlet). The volume of each chamber starts to decrease, thus compressing the trapped air until it reaches the required built-in pressure ratio. Finally, the valve opens, releasing all the pressurized air.
Positive displacement air compressors are the most common type of compressors; they are widely used in plants, large construction sites, and industrial settings. There are four types of positive displacement compressors; they are:
- Tooth compressors
- Piston compressors
- Screw compressors
- Scroll compressors
Four Main Types of Air Compressors:
Now that we have talked about the two main ways of categorizing air compressors, we will discuss the four main types of air compressors. They are:
- Axial compressors
- Centrifugal compressors
- Rotary Screw compressors
- Reciprocating Air Compressors
1. Axial Compressors
They are the most expensive type of compressors out there. They are only used in high-speed engines that are used in ships or airplanes. They are extremely expensive due to their massive size, extreme efficiency, and their ability to provide many thousands of horsepower. All these factors make axial compressors used for aerospace research only.
2. Centrifugal Compressors
These are multi-stage compressors that are capable of dishing out around 1000 horsepower. They are relatively smaller than the other types; however, they are capable of producing high amounts of energy due to the multi-stages compression process.
They build potential energy by cooling and slowing air that is coming through the diffuser. They are more commonly used in larger and more demanding construction sites such as chemical plants due to them not needing much maintenance as well as their strength and efficiency.
3. Rotary Screw Compressors
They are the most common type of compressors; they come in oil-lubricated or oil-free models. They are easily maintained and taken care of as the internal cooling system does the job. Moreover, their horsepower ranges from five hp to 350 hp; this makes them perfect for use anywhere from homes and small shops to large construction sites. They are also designed for continuous usage that can extend to many hours without needing to stop.
They contain two internal rotors that rotate in opposite directions, trapping the air between them (the two rotors) to build up pressure and generate energy.
4. Reciprocating Air Compressors
These compressors are more commonly used in small construction sites and at homes. As they are not designed for continuous use. They contain a lot of moving parts that must be lubricated using oil. The pressure that these compressors can achieve ranges according to whether they are single-stage or multi-stage. They contain a cylinder which has a piston inside it. This piston compresses and displaces the air to build pressure.
The multi-stage reciprocating air compressor provides you with more power, and they are suitable for large construction sites such as auto-assembly sites as they can dish out about 30 horsepower. In contrast, single-stage reciprocating compressors are suitable for small projects like power pneumatic tools used in woodworking or metalworking.
Finally, it is safe to say that air compressors are indispensable tools that are very beneficial. However, there are some factors that you need to consider before purchasing one such as their portability, whether they need oil or not, and finally, their speed and horsepower.