How Does an Air Compressor Work?

How does an air compressor work? 

A compressor builds up the air inside its chamber (storage tank), and, when full, it shuts down and stores the air inside ready for use.

During use, the air inside the tank reduces, and the compressor then re-pressurizes itself to ensure a constant supply of compressed air. 

Air compressors have a wide range of applications, and they are used in different places. From gas stations to large industrial plants, they work by converting power into compressed air.  

Air compressors differ from a pump because they work pressurizing gas or air while pumps work exclusively with liquids.   

General Air Compressor Info 

To further answer the question of how does an air compressor work, let’s discuss two important factors:  

• The method of air compression and 
• The pressure they deliver 

Most Popular Types of Air Compressors: Compression Methods 

When looking methods of compression, we have 2 main types of air compressors: positive displacement compressors and dynamic displacement air compressors.  

Each of these types of air compressors can be divided into 3 different level of pressure.  Make sure to check your air tools or paint sprayer for the amount of PSI you will need to work continuously.   

Most paint sprayers don’t require a ton of air to operate, usually less than 50 PSI, but brad nailers require considerably more air to work without delays.  It’s a bummer to have to wait for your compressor to catch up to your air tools so make sure you grab the right size for your tools. 

• Low-pressure tanks (150 PSI or less) 
• Medium-pressure tank (150-1,000 PSI) and 
• High-pressure tank (over 1,000 PSI) 

​Positive Displacement Compressors 

Positive displacement compressors are the most common type you’ll encounter. They work by trapping air inside a chamber and squeezing it until the pressure reaches the set limit. Once compressed, the air is released through outlet valves as needed.

There are three main varieties of positive displacement compressors:

• Rotary Screw Compressors: These use helical screws to draw air in and gradually reduce its volume as it’s compressed inside the tank.
• Piston Compressors: Using pistons and one-way valves, these push air into the tank’s chambers to build up pressure.
• Vane Compressors: Featuring a slotted rotor, they channel and compress air by spinning inside the chamber.

Dynamic Displacement Compressors 

Dynamic displacement compressors operate differently—they use spinning impellers (either centrifugal or axial) to add kinetic energy to incoming air, turning it into high-pressure compressed air.

By accelerating or slowing down airflow, these compressors adjust the air pressure dynamically.

Dynamic compressors are known for their efficiency, low energy consumption, and high output capacity. With fewer moving parts than positive displacement models, they’re also easier to maintain. Their ability to handle a wide range of pressures and flow rates makes them versatile across many industries.

However, they can be noisy and produce significant vibration. They’re sensitive to fluctuations in gas flow and pressure, often requiring extra equipment to keep these in check. Plus, their initial purchase and installation costs can be quite high, especially for large industrial setups.

How Do Portable Air Compressors Work? 

How does a portable air compressor work? The best way to learn this is to read your user manual carefully before you start operating the device. However, for portable air compressors, I find it’s easy and straightforward to operate them.  

1. Start by checking that everything is in peak condition. By everything, I mean the oil and fuel levels, battery level, hoses are in good shape, attachments are on tight etc.  
2. Close all the air outlet valves and turn on your compressor by pressing the start button. 
3. Give your device some time to warm up, and, once it does, proceed with your work 
4. When shutting it down, start by closing all the outlets and give it time to run for several minutes, as it reduces its engine speed and cools down. Once it cools, you can press the stop button.  

Most portable air compressors have a single-stage piston design. This makes them lighter in weight and easier to carry.  The piston forces air through the inlet valves, compresses it, and then discharges it through the outlet valve. 

​They also require less maintenance because they are made with less moving parts.  Perfect for DIYers to use at home.   

How Does an air Compressor Regulator Work? 

A regulator is a valve that ensures there is constant pressure being supplied to any type of fluid. Every air compressor has a regulator within its system.  

This component works by stabilizing the air supply being delivered through the outlet no matter what the air pressure may be on the inlet side. It restricts the flow of air based on the settings you put in place.  

Regulators use springs that move up or down, this, controlling the area left for air to pass through — a sensor, known as a diaphragm, shifts as the pressure changes.  

It is important to ensure a smooth transition between the air pressure changes. Switching instantly to very high or very low pressure can damage your regulator and compressor.  

When you turn on an air compressor, it runs until your pre-set air pressure setting is reached. From there, the regulator ensures this pressure is maintained during use by providing the right amount of air pressure that is needed for your job.  

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How an Air Compressor Works: See it on YouTube 

Check out this video that will help you have a better understanding of how air compressors perform their tasks.  

How Does a Small Air Compressor Work? 

Small tank air compressors basically use the same principles outlined in the processes above. The only difference between them and bigger compressors is that they use fewer pistons. Most of them operate on 1-stage piston pumps, and because of this the power and PSI output is not as much as the bigger compressors.  

How do Air Compressor Pressure Switches Work? 

For you to fully understand how an air compressor works, let’s look at the mechanics of air compressor pressure switches.  

When you’re using a compressor, you might expect the pressure to drop as the air inside the tank runs low—after all, less air means less pressure, right? But thanks to the pressure switch, that pressure stays steady, and your work doesn’t skip a beat.

Here’s how it works:

The pressure switch constantly monitors the air pressure inside the tank. It’s wired to both the power supply and the motor. When the pressure drops to a certain level—called the cut-in pressure—the switch kicks in and allows power to flow to the motor.

The motor then fires up and pumps fresh compressed air into the tank, bringing the pressure back up to the set level. This cycle keeps your compressor delivering a steady PSI output, so you get consistent performance throughout your project.

Conclusion 

I hope I have answered all your questions about how does an air compressor work. The overall concept is that they take in air, compress it inside the tank, and then control how it’s let out.   

Of course, there are other processes involved, such as pressure control using regulators and pressure switches, but, all in all, the above processes are the basics of how an air compressor works.  

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