Whether you are tackling small-scale DIY projects or need a large industrial-scale machine, air compressors are a valuable tool to possess.
From spray gun in auto-repair shops and scuba equipment to roller coasters and snow machines, air compressors can be used for a huge variety of applications.
Air compressors are an amazing way to save energy as they create an immense amount of power from a small amount of electricity or gas. Saving you cash and reducing your carbon footprint, an essential element to reduce climate change.
But, have you ever wondered how these air compressors work? Understanding these machines will aid in choosing the right machine for you and your business. Direct Air has created a guide to help you gain an understanding.
The infographic below Direct Air shows how a Hydrovane series rotary sliding vane air compressor works but there are numerous other forms of a compressor.
The two main categories are the scroll (piston) and rotary screw (reciprocating) compressor, between these two, you have a tool for every form of the commercial and industrial setting along with domestic uses.
Low Noise Air Compressors
Firstly, it is of the greatest importance that your own health and safety is taken into consideration. The most frequent complaint of air compressors is the noise they make and without adequate protection, they can cause long-term damage to your hearing. There are numerous brands of air compressors in the market today that produces low noise-level, one known brand is Porter cable. If you're planning to get one, best to check Best Of Tools review and guide on how to use a porter cable air compressor to get you guided.
60dB is considered a safe level and anything over 85dB can have an impact on your hearing. Low noise air compressors use the addition of an acoustic chamber to reduce noise to at least 40dB.
Dual and Single Phase Air Compressors
These are the most common type of air compressor and they function in a very similar manner, dual-phase has one more step to the process.
In a single-phase, the air is drawn into the cylinder and compressed in one single piston movement. This compression is typically around 120 PSI (pounds per square inch), a dual-phase compresses air to around 175 PSI by transferring the air to a second chamber for a second compression.
Both machines then draw the air into a storage cylinder, awaiting usage.
As a single-phase has fewer elements, they are therefore lightweight and compact. Perfectly suited to home use. A dual-phase is more robust and can typically be found in industrial settings.
Oil and Oil-Free Air Compressors
All air compressors require a lubricated cylinder to safely and effectively draw in air. The variation between machines is how this lubrication is achieved.
Oil-based compressors use oil for lubrication, the alternative is an oil-free machine. Oil-free use a non-stick coating, such as Teflon. Although these machines are smaller, due to fewer elements, this non-stick coating will eventually wear away, leading to the machine needing to be replaced.
By selecting an oil-free air compressor, you can help in reducing your use of fossil fuels and in turn reducing your negative impact on the environment by eliminating harmful emissions and conserving precious natural resources. An oil-free air compressor will also provide a clean, cost-effective and reliable source of air.
Oil-based machines are more robust and although they require more regular maintenance and oil top-ups, they are the most suitable compressors for industrial applications. Oil-free does have a place outside of a DIY setting, they are often used within the health and food industry as it eradicates the risk of oil contamination.
Fixed and Variable Speed Air Compressors
If you are looking for the most economical machine, this is the most important element to consider. The difference in these tools is the manner in which the motor gets its power.
Fixed-rate sends a continuous stream of power to the motor. In return, this provides a reliable frequency. They are often cheaper and easier to maintain but are less energy-efficient than their counterpart.
Variable speed compressors, also known as VSD (Variable Speed Drive) or VFD (Variable Frequency Drive) automatically adjust their speeds in relation to the demand for air. Although more complex and higher in initial cost, VSD compressors can save money in the long-term as they do not waste energy.
They achieve this by converting energy twice, firstly to AC and DC with the use of diodes. This acts as a switch to control the frequency of power.
Piston, Scroll and Rotary Screw Compressors
All machines previously mentioned use pistons which is a generic operating system for the scroll (also known as reciprocating) air compressor.
Scroll compressors are the most common type of air compressor due to their availability and affordability. A piston travels downwards which decreases pressure in the internal cylinder, forcing the chamber door open.
Air is then drawn in, the piston travels upwards and the change in pressure causes air to be forced out of the cylinder at a much higher pressure point. This then repeating in a scrolling manner, hence the name.
These air compressors can cool down quickly and are more efficient in energy use. However, they are more costly and due to complex parts, they are harder to maintain.
Instead of pistons, rotary screw compressors use rollers for compression. These rollers are positioned just off the middle of the central shaft and rotate at extreme speed to achieve the same result as a piston.
These machines have a good power capacity, are easier to maintain and are lower in the initial cost. They are limited in their cooling abilities and require frequent maintenance checks.