How do air compressors work?

Throughout many industries, Air Compressors are an incredibly valuable tool. With uses from scuba equipment to spray guns, they have a plethora of functions. Direct Air have created a handy guide on the workings of air compressors to help you gain a better understanding of these machines and aid you in your choice when selecting your purchase.

Air compressors are a popular, durable tool. The two main categories are scroll (piston) compressor and the rotary screw (reciprocating) compressor.

Low Noise Compressors

One of the most common complaints regarding air compressors is the noise level. Consider where this will be used and if you or staff are going to be exposed to high decibels frequently.

Anything over 85bD can cause damage to your hearing. There are models that produce less sound, this is achieved by an acoustic chamber added to store noise. This reduces the noise level to roughly 40dB, making them a lot safer.

Fix Speed and Variable Speed Compressors

The speed of your compressor needs to be considered when shopping around. Fix speed models send a continuous stream to power to the motor, in turn, this provides a reliable frequency. They are cheaper to purchase than their counterparts and typically easier to maintain.

However, they are less energy efficient, therefore they can be most costly to run. In addition, they have a larger impact on the environment. Variable speed compressors adjust the power stream in accordance to the demand meaning they are cheaper to run.

This is done using AC and DC power and means the motor can be controlled closely. They are most suited to tasks that require a continuous power stream.

Single and Dual Phase Compressors

These air compressors work in a very similar way, dual phase has one more step to the process. A piston is drawn down, creating pressure in a vacuum which forces the cylinder open and draws in air. When the piston travels back up, the air is forced out at a higher pressure.

The air is then sent to a separate tank for storage until needed. Dual phase follows this, but the air is sent to an additional cylinder to be compressed a second time before storage. Single phase is most suited to home use while dual phase work best for industrial applications.

Oil-Free and Oil Air Compressors

All air compressors require lubrication to be able to draw in air efficiently and safely. This can be achieved with the use of oil within the cylinder. These machines are heavier as they have added elements and do of course require oil top-ups.

They can be more costly as they require more maintenance. They are however, more robust and tend to last longer. The alternative is oil-free, this have a non-stick coating within the cylinder, typically Teflon. They are more light-weight and suitable for home use as they are often more compact and need less maintenance.

Unfortunately, their lifespan us usually shorter as this coating will eventually wear away.

Scroll Compressors

These are a type of piston compressors and are also known as reciprocating compressors. They are the most common due to their affordability and availability. The piston travels downwards which decreases pressure in the cylinder. With the pressure suddenly changing, this forces to cylinder open and draws air in. The piston then travels back up and air is forced at a high-pressure point, this is then repeated.

These machines can cool down quickly and have an efficient energy use, but they are costly to purchase and require regular maintenance.

Rotary Screw Compressors

This works in a similar way to scroll compressors but use rollers instead of a piston. The rollers are positioned in the central shaft and one side is always in contact with the walls. These rotate at extreme speeds to achieve the change in pressure.

These machines have a good power capacity and are more affordable to initially purchase but do have a limited ability to cool and require regular maintenance checks. There are many factors to consider when purchasing an air compressor. Always consider the applications it will be used for; will it be used occasionally or or will you require continuous use?

What is your budget, not only for initial cost but for future maintenance? With these in mind, you should now be on your way to finding the right air compressor for you and your business.

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