How Do Air Compressor Work?

How Do Air Compressors Work

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An air compressor can be used for various kinds of jobs such as powering tools like nail guns and paint sprayers to filling tires up.

But the mechanism behind how compressors work may be more than meets the eye. And by understanding it, you’ll understand the type of compressors you need for your work and how to maintain it.

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All compressors consist of 3 main components, and these are:

Drive:    

The part that provides the power to propel the compressor’s pump. It can be either a gas engine or an electric motor.

Pump:

The part that uses the energy from the drive to absorb atmospheric air and compress it until it reaches very high pressures.

The compressed air is then sent into a storage tank for later use through a discharge tube.

Storage Tank:

This part is equipped with a check valve –a one-way valve that prevents the compressed air from applying back pressure on the pump.

The air storage tank spares you the need to run the compressor continuously as it works as an airflow buffer. This way, there’s less wear and motor damage from overheating.

Inside the air tank, the air is stored at a pressure that exceeds the room (atmospheric) pressure and it’s waiting to return to the outside pressure.

That’s why air escapes once the regulator is opened.

This compressed air can be used to perform work such as spraying paint, operating devices, and powering tools.

The atmospheric air drawn into the tank contains water molecules that don’t stay suspended in the air when under increased pressure at room temperature.

This results in the water molecules to get condensed in the storage tank.

To manage this moisture, each tank is equipped with a drain valve at its bottom which enables the user to drain this trapped moisture.
Therefore, the user can maintain the tank volume and prevent its corrosion.

Moreover, air compressors come with a pressure switch that automatically starts the device when the air pressure in the tank is less than the rated cut-in (also known as the “on” pressure). It also stops the device when the tank pressure reaches the cut-out (or the “off” pressure).

The air pressure inside the tank is always monitored by the tank pressure gauge.

After you turn the compressor off, an unloader valve releases the pressurized air into the discharge tube. This enables the pump to start without the need to overcome the resistance caused by the trapped air.

An unlikely event is the pressure switch failing to shut off the compressor. In this case, you can use the built-in safety valve to release the excess pressure.

You shouldn’t adjust the safety valve and pressure switch on your air compressor as they are factory set for safe operation.

On portable air compressors, the regulator is provided and enables you to adjust the outlet pressure of the air flowing into the tool.

To work properly, most air tools will operate on an air pressure of about 40 PSI to 90 PSI.

The regulated air pressure is displayed on the outlet pressure gauge that’s found on the regulator. This pressure should be set dynamically as you operate the tool.

This is the general way an air compressor works. However, the small details may differ from a single-stage and a two-stage compressor.

Single-Stage

piston-type air compressors are the common models for home use as they work just fine for various applications around a workshop or home.

They can employ either an electric motor or a gasoline engine to drive a piston that compresses the air and forces it into the storage tank.

And the more air the piston forces in, the higher the pressure rises.

Once the pressure reaches a certain level, the compressor stops running.

And as you use the stored air to power a tool, the compressor begins to build the air pressure again.

Two-stage

compressors have two pistons. The first one compresses the air and forces it through a check valve to the second piston.

The second piston, then, compresses it even more and forces it into the tank.

Two-stage compressors are more suitable for heavy-duty, commercial use as they can deliver greater volumes of air at higher pressures and pounds per square inch (PSI) levels. That’s why they’re more commonly used in shops or to power multiple tools simultaneously.