Air Compressor Types and Working Principle

 

Air compressors are versatile machines commonly found in factories, large industries and household settings. They act as a food supplier – a source of power – for electrical tools and machines. That doesn’t mean the one used in a large manufacturing plant will be the same as the one used for simple tire inflation or small house repair projects. 

Due to their widespread use, it is necessary that you learn about the various types of air compressors. It might seem rocket science to some, but you should also know about the process each air compressor employs to get the output it is supposed to get. 

Types of air compressors and their basic working principles are explained in this article. Lets start to get some answers. 

What is an Air Compressor?

An air compressor is a machine that imprisons a large amount of air into a storage tank by decreasing its volume to increase pressure. That pressurised air – converted form of power – in stored form is potential energy that turns into kinetic energy when released for an array of applications. For instance, they act as a power supplier for electric tools. They’re also used in factories, workshops, plants, construction sites etc.

Working Principle of Air Compressors

Air compressors come in various kinds, each having a speciality along with a set of advantages and pitfalls. They generally differ from each other based on the path taken for compressing air. The working principles can be explained in two broad terms: 

1. Positive Displacement
2. Dynamic Displacement

• Positive Displacement: This is a method in which the air is forced into a chamber where its volume is reduced to raise the pressure. The common air compressors that follow this working principle are: 

1. Rotary Screw Air Compressors
2. Reciprocating Air compressors

• Dynamic Displacement: This method uses a rotating blade or impeller to generate airflow. That air is then restricted to produce pressure. The air compressors that fall under this umbrella term are:

1. Centrifugal Compressor
2. Axial Compressor 

• Rotary Screw Air Compressor

Rotary Screw air compressors are the easiest and simplest kind of air compressors due to their easy operation and low maintenance. They have two internal rotors placed in an air-tight casing where they continuously move in the opposite direction to generate energy. This constant movement traps the air in a small space between the rotors to build up pressure. They have an internal cooling system due to which they’re reliable for continuous use. Their power range varies from 5HP to 350HP. These machines are large and industrial-sized and are ideal for demanding industrial applications. 

• Reciprocating Air Compressors

This type of air compressor differs from rotary screw based on having more moving components. These parts require lubrication for smooth movement. These air compressors work through pistons which are housed in a cylinder. These pistons act on the commands of a crankshaft for displacing air to generate pressure. 

Unlike rotary screw compressors, these are not designed for continuous use. Therefore, they are most commonly found in garages and home construction or renovation projects. These piston air compressors can be sub-divided into two types: 

• Single-Stage Air Compressors: This type of air compressor uses one side of the piston to compress air. It is appropriate for applications varying in pressure range from 70psi to 100psi. These air compressors are easily available and comparatively more budget-friendly. 

• Two-Stage Compressors: these have compressions on each side of a piston. They have a better cooling mechanism than others and are usually ranged from 100psi to 250psi. They are also comparatively expensive. Due to all these factors, they’re considered better for workshops and industries. 

• Centrifugal Compressor

Centrifugal Compressors are also called “Radial Compressors”. This form of air compressor uses a rotating impeller to bring in air. That air is then forced forward through centrifugal force. A diffuser is used to slow down the airflow in order to generate more kinetic energy. Thus, the air is forwarded at a higher pressure to the receiver. 

As compared to rotary screw and reciprocating compressors, these require less maintenance. As they’re capable of reaching up to 1000 horsepower, they’re best for extensive applications like chemical plants. 

• Axial Air Compressors

These are gas compressors that work via turbine blades to produce air. These compressors employ stationary blades to slow down the airflow to raise pressure. These devices are famous for acquiring thousands of horsepower and having an extremely high efficiency rate, due to which they’ve limited functionality. They are mostly reserved for aircraft engines, large air separation plants and aerospace research. They are also extremely expensive.

Conclusion

It’s time to wrap up. As air compressors are essential for an array of applications, so it’s better to know the common types and how each one of them works. We briefly introduced you to the popular air compressor types and the process they adopt to acquire air compression, making sure you gain more knowledge in a shorter time. 

With this knowledge in mind, you can easily pick the type of air compressor that will work for your needs.