Without air, nothing is able to function on our planet and the same goes for machinery. Although not as strong or as useful as it initially seems, pressurised air can be used for more than just clearing out dust or pumping your tyres. Thanks to air compressors though we are able to keep air under a certain pressure and then release it when we need it at the pace we want to.
This happens mainly thanks to the use of pistons which displace air and by doing so they compress it into a smaller chamber or tank so that when it needs to be used it comes out under a lot of pressure. But different petrol air compressors work differently.
Types of Air Compressors
Rotary-Screw
A rotary-screw air compressor relies on two screws in order to reduce the volume of air inside. Thanks to the meshed twin spiral screw the air payout and intake are maximised and thus positive displacement happens. This means a rotary-screw petrol air compressor is able to fill a sealer chamber with air and make it move between the rotating screws.
Reciprocating
With reciprocating piston petrol compressors you can expect to have a tried and true solution since it relies on the above-mentioned displacement method. Similar to how an engine works, a reciprocating air compressor can often be found used in refrigeration and in agriculture as it works by moving its pistons back and forth. This makes for a low-maintenance unit that is easy to move around.
Scroll
A scroll compressor is made to deliver different levels of intensity when it comes to air pressure. Thanks to a spiral-shaped scroll, this type of compressor is able to reduce air volume thanks to circular motion alone. This makes scroll compressors quieter than reciprocating ones and also longer lasting too.
Stationary vs Portable
No matter the internal process of pressurising air, a compressor can be either portable or stationary. Stationary petrol compressors are much larger and therefore more capable than portable ones. If you want a compressor with a petrol engine that is going to be easier to lug around then the choice you need to make is quite an easy one, just keep in mind that you won’t get the most powerful compressor.
What to Look for in a Petrol Air Compressor
PSI
Air pressure is measured in PSI or pounds per square inch. Also expressed in Bar it provides you with the amount of pressure at which the compressor can exert air the air. The higher this number is the greater the air pressure the compressor can generate. This means that the compressor can power more demanding tools and it can be used in more demanding applications too.
CFM
The average CFM or cubic feet per minute of an air compressor refers to its ability to compress a volume of air at a certain PSI. Again, the higher the CFM of a compressor the better it’s going to handle more pressurised air and the more powerful it is. This way you can use the compressor to power air tools for a lot longer before you need to give the compressor some time to rest before you use the tools again. Meaning the compressor will have a better duty cycle.
Tank
Air compressors come with tanks where the pressurised air is stored. The larger the tank is the more air the compressor can have ready to go at any given time. But remember that a larger tank makes for a heavier and less portable one too. As long as you go for a compressor with a big enough tank to satisfy your needs you won’t have to worry about it being portable since if you do need a heavy-duty compressor portability is going to be out of the question anyways.
Oil vs Oil-Less
Although a petrol air compressor works much like an internal combustion engine it can either work with or without oil. Petrol compressors that make use of oil are usually much more powerful than those that don’t. Oil-less compressors are low-maintenance units that are going to stay free from contaminants. But keep in mind that compressors with oil are going to be much quieter than those without it.
Direct vs Belt Drive
A direct-drive compressor is a more sophisticated verso of a belt-driven compressor. The absence of a belt makes them a great option if you’re someone who will occasionally use a compressor. But if you want a compressor with a petrol engine that will run almost all of the time then a belt-driven compressor is recommended as it is much more reliable and it can take on a lot more work hours. Belt-driven compressors are the workhorses in this case while direct-drive compressors are considered to be adequate for home use.
HP
The number of horsepower a petrol compressor has determines how powerful it’s going to be. This specification affects both CFM and PSI levels and it can reach up to 10 HP. While this may not be a lot, in the world of air compressors it is and it’s found mainly o heavy-duty compressors. Typically a compressor with 2 HP is going to be powerful enough for general use.
Industrial Knowledge 