Tips and Tricks

How Does An Air Compressor Work?

Written by Eric Johnson

The world is full of air. However, it is only recently that humanity has managed to find a way to harness the power of air in order to make work easier. There are a number of applications that are powered by air. Specifically, there are a number of applications that are powered by compressed air. Specifically, you can find compressed air at work in the following applications:

  • Drills
  • Hammers
  • Cars
  • Mechanics
  • Special Effects
  • Painting
  • Much more!

Compressed air, unknown to some, helps to power the world around us. It runs a fair share of the tools on construction sites, helps to power your car, plays a role in a number of automotive repairs and maintenance procedures, and helps Hollywood to make movie magic. Although it has myriad applications, none of this answers the most important question of them all; how does compressed air work?

Producing Compressed Air

There are two elements of compression that should be taken into account. One is pressure and the other is volume. As some readers will know, these two qualities are related. If you take a fluid that is at one pressure and reduce the volume of that fluid then the pressure will go up.   Likewise, if you have a certain volume of fluid and then add pressure then the volume will drop. This makes sense if you consider playing in the pool. If you hold water in your hands and then add pressure by blowing, then the water squirts out. In the same way, if you have water in your hands and then close them, or reduce the volume, then the pressure increases and the water once again will come out of your hands.

Air compressors work along similar principles. Different types of air compressors utilize these principles in different ways. As a result each type of air compressor works in different ways and has its own different qualities, but each manipulates one or both of these physical realities.

Air compressors are powered by gas or electric motors that use different mechanical processes to increase air pressure and decreasing its volume. Air compressors are frequently attached to tanks that are rated to store different amounts of air under different pressures. The air can be stored until it is needed to power the various devices that use it or to perform some of the special effects that make Hollywood magic. The motor starts and stops to keep a consistent level of pressure in the tank.

Broadly speaking there are two different types of air compressors, although there are variations on each. These types are rotary screw compressors and piston air compressors. Each of these different types of compressors has its own different uses and will be discussed below.

Rotary Screw Air Compressors

Rotary screw air compressors work by using sets of blades to move air into a smaller space, compressing it and increasing the pressure. The blades move in rotation with each other sucking in fluids. Rotary air compressors often have variable speed settings and thus are able to generate different levels of pressure. Because of this, rotary screw air compressors are often used as multi-purpose air compressors, running multiple different pneumatic tools and devices by adjusting the compressor to the appropriate pressure for the given device.

Rotary screw air compressors are generally better for tasks that involve a need for a high degree of precision with air pressure consistency. The bladed design of the rotary screw works more smoothly and continuously than the piston method. These needs usually lie with those individuals working with extremely high pressures to perform highly specialized and dangerous tasks.Consequentially, most people who need air compressors and most tasks that air compressors can be used for can be serviced by piston design air compressors.

Piston Air Compressors

Piston air compressors operate by the simple mechanic of sucking in a volume of air, sealing it off, and moving a piston down to decrease the volume of the container holding the air. The resulting higher pressure air can then be stored in a tank or put directly to use. Piston air compressors are the most common types of air compressors used in everyday applications, from automatic hammers and drills to jackhammers and tire pumps. The piston mechanism has fewer moving parts than the bladed design and, as a result, is easier and therefore cheaper to manufacture. Consequentially, piston design air compressors are generally cheaper to manufacture and easier to maintain than bladed designs. However, because the piston mechanic takes much longer to generate pressure than the bladed mechanic, the pressure it produces can feel uneven when operating near the edge of your compressor’s abilities. As a result of this trait many individuals who need high precision consistency prefer bladed designs.

So It Works Like This…

The compressor uses some mechanism, either a piston that draws air in, reduces the volume and thus increases the air pressure, or a blade creates rotational force that pulls air in, increases the pressure and compresses it. These mechanisms can be powered by either a gas or electric motor and each has its own strengths and weaknesses.

What Air Compressor is Right for You?

The type of air compressor you need depends on the task that you intend to execute with it. Some people using pneumatic hammers can use a simple piston compressor. However others, such as those doing precision or artistic metal crafting might need to be sure to have a tighter consistency with their pressure and thus prefer a bladed design. This example shows how different tasks require different types of air compressors. If the task you are looking to preform requires a high degree of precision or consistency then you should opt for a bladed air compressor. However if you are doing work that is less precise or is just routine work that you want to make easier with a pneumatic tool, then a piston air compressor will probably fit your needs. Ultimately, as long as you can answer the question “how does an air compressor work?” you will be ready to overcome any obstacle.

About the author

Eric Johnson

Currently residing in San Diego, CA, Eric is a football lover, handyman, and creative consultant. Working to share my experiences in construction both online and in real life.

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