Surely you have been thinking lately about purchasing an air compressor, since perhaps you are one of those people who have a small workshop at home for their weekend projects, or you have a small contracting company that is opening to be born and you require tools of this type, or maybe, you by this time have a company united and want to expand or remodel and renovate it and you are thinking of more automated and efficient tools for this new stage of work.

Therefore, that is, no matter what your reason, I would like to share on this page everything you need to know about the tools that generate energy through the use of air, so that you can be better informed when purchasing one or more. Know what each one works for when ordering and working.

What’s an air compressor?

An air compressor is a machine that transforms power (using an electric motor, diesel or gasoline engine, etc.) into possible energy deposited in pressurized air (compressed air). By one of numerous procedures, an air compressor pushes more and more air into a stowage tank, growing the pressure. When tank pressure stretches to its engineered upper limit, the air compressor shuts off. The compressed air, then, is maintained in the tank until called into usage. The energy contained in the compressed air can be used for a diversity of solicitations, utilizing the kinetic energy of the air as it is released and the tank depressurizes. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank. An air compressor must be differentiated from a pump because it works for any gas/air, while pumps work on a liquid.

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How to buy an air compressor

Buying an air compressor consists in more than purchasing the most popular model or rushing to buy before the sales are gone, before taking any step towards the store, you need to take a few minutes to think about what you want the air compressor for. More precisely, what do you want the compressed air to do for you?

A common thing to see is that, when working on a woodworking project, you usually require a small air compressor with a blow gun attachment to dust off the wood itself, and clear chips and sanding debris from the shop tools. This is all the main purpose of the air compressor in this particular case, it will serve as a quick and easy method of blowing clean projects and woodworking tools. Other of the most common uses are maybe inflate the odd bicycle or car tire. But air compressors purposes don’t limit themselves to the latter, and can be used for much others, that’s why you need to determine which one if the objective that you have set for the compressor before taking any move towards purchasing it.

Like enlisted before, the main uses for an air compressor are:

  • Cleaning bench and tools with a blow gun
  • Inflate a tire or football
  • Maybe periodic use of a small – air driven nail gun

If this is all you want your air compressor to do for you, then you can find an air compressor that’s on auction, runs with a 120 VAC power supply (you plug it in an average outlet), if is an oil-less or oil free design you won’t ever need to add lubricating oil, and it would be preferable for your compressor to have a small air tank to hold a reservoir of air.

Don’t be too worried about the air compressor trademark, source, whether or not there are spare parts available now or ever. Instead, worry to get one that offers a guarantee though, just in case the compressor doesn’t work out-of-the-box, which occurs more frequently than you may think. The warranty means you can take it right back to the store and get a replacement if you ever see yourself in one of these situations.

Types of air compressors

Positive Displacement

Positive displacement compressors cab be further divided into reciprocating and rotary compressors.

Under the classification of reciprocating compressors, there are:

  • In-line compressors
  • “V”-shaped compressors
  • Tandem Piston compressors
  • Single-acting compressors
  • Double-acting compressors
  • Diaphragm compressors

The rotary compressors are divided into:

  • Screw compressors.
  • Vane type compressors
  • Lobe and scroll compressors and other types.

Roto-Dynamic Compressors

Under the Roto-dynamic compressors, there are centrifugal compressors, and the axial flow compressors.

The compressors are also classified based on other aspects like:

  • Number of stages (single-stage, 2-stage and multi-stage)
  • Cooling method and medium (Air cooled, water cooled and oil-cooled)
  • Drive types ( Engine driven, Motor driven, Turbine driven, Belt, chain, gear or direct coupling drives)
  • Lubrication method (Splash lubricated or forced lubrication or oil-free compressors)
  • Service Pressure (Low, Medium, High)

Reciprocating In-line Compressors

These are most frequently used compressors with fluctuating pressure arrays. These are simple in design with almost very little automation. The cylinders of various stages are found in a straight line when seen from top. These compressors are usually direct driven by electric motors or diesel engines.

“V”-Shaped Compressors

These are regularly air cooled compressors with concentric regulators fixed on each cylinder head unit. The compressor has diverse units shifted generally by 90 degrees, may or may not be connected to same crank pin on the crank shaft. Higher capacity compressors are water cooled. Better rotation and balancing is achieved by displacing the units by certain angle.

Single-Acting Compressors

These are typically reciprocating compressors, which has piston employed on air only in one direction. The other end of the piston is frequently free or open which does not perform any work. The air is compressed only on the top part of the piston. The bottom of the piston is open to crankcase and not used for the compression of air.

Double-Acting Compressors

These compressors are devising two sets of suction/intake and delivery regulators on both sides of the piston. As the piston travels up and down, both flanks of the piston are used in compressing the air. The intake and delivery regulators function conforming to the stroke of the compressor. The compressed air delivery is moderately constant when paralleled to a single-acting air compressor. Therefore both flanks of the pistons are efficiently used in compressing the air.

Rotary Compressors

These compressors are not of reciprocating nature, consequently does not have any pistons and crankshaft. In its place, these compressors have bolts, vanes, scrolls, and other devices which rotate and therefore compress air. The rotary compressors are classified into screw type, vane type-lobe type, scroll type and other types.

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How do air compressors work?

It’s simple to think of an air compressor as a very common piece of equipment, nevertheless, things weren’t the same in the past. In reality, not that long ago, a compressor wasn’t a thing you would have located in a factory or industrial unit.

In its place, tools operated in the shop were drove by a compacted foundation which transported the energy in numerous methods dependent on the tool. Frequently it was over and done with a system of helms, straps or drive shafts. It was a big motorized arrangement that was way too large and way too high-priced, and consequently merely accessible to specialists.

These days we come upon air compressors pretty much in all places. Their ordinary place is in gas stations where we usually usage them to fill tires. They can be located in manufacturing works, factories, even your resident mechanic will make use of a tool like this.

Power tools such as sanders, pounders, staplers, nail guns, spray guns, bradawls, impact wrenches, and lots of others are motorized by them too. You can likewise purchase one for automatically online, at your local hardware store, or home depot.

Obviously, the main benefit of compressors over a consolidated energy foundation is their minor dimension, and the detail that they don’t need an immense motor. They are also silent, more long-lasting, and some of them are extremely moveable. But, must of us don’t really know what’s going on inside this machines, even with all of their advantages over others, so let’s see the bass of the functioning of the air compressors:

Basic Piston Functionality

Air compressors operate founded on an extremely uncomplicated standard. When the air is compressed, its bulk falls while the pressure rises.

The most ordinary method to accomplish this is with the help of a reciprocating piston. There are compressors which utilize spinning impellers for the intent of generating air pressure. Those which are built around a reciprocating piston are more common, and if you’re familiar with how internal combustion engines work, you will know piston compressors function in a similar manner.

Advantages and disadvantages of air compressors

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Each reciprocating piston compressor has a crankshaft, connecting rod, a piston, cylinder, and a valve head. In order for the entire mechanism to work, you need power. Air compressors are usually motorized by voltage or gas depending on the model. Most compressors also have a tank which is there to stock compressed air for the objective of keeping the air pressure within a set range while powering various air tools. But, let’s get back to the mechanics of it.

At the top of every compressor cylinder there is a regulator head that encompasses both the inlet and discharge regulator which are essentially metal blinders. These open and close and are situated on top of the regulator plate. When the piston moves down inside the cylinder in the space above the piston a vacuum is formed.

The dissimilarity in pressure on the inside of the cylinder to the exterior permits the atmospheric pressure to open the inlet regulator. The air then comes in the area where the vacuum used to be, and is compressed by the piston which is now going up. The inlet valve closes and the discharge valve is opened. The compressed air is stored inside the tank thereby increasing the pressure.

Dual Piston

There are variations to this approach but the basic principle is the same. Dual-piston compressors are also very common, and they function in the same way as their single-piston counterparts do. The only real difference is there are two strokes per revolution and not one. The most common variation of a dual-piston compressor is the two-stage compressor which uses one piston to pump air into a second cylinder which creates greater pressure.

In order to keep the pressure within the preferred limits, and to stop the tank from blow up each air compressor has a control which cuts the power to the motor when pressure inside the tank has gotten to the limit (which is usually around 125 PSI). With the intention of adjusting the pressure depending on the power tool linked to the compressor there is a regulator as well as devices before and after the regulator.

These measure the pressure inside the tank and air-line respectively. In case the pressure switch doesn’t go off, there is a safety valve as well as an unloader valve which is there to reduce pressure inside the tank when the compressor is not being used.

If you want to know more about other types of compressors, I recommend you read the following articles:


Another main thing you should be familiar with about air compressors is the way they are lubricated. You will come across terms like “oil-free pump”, or “oil-lubricated”. Oil-lubricated pumps have an oil bath which lubricates the bearing and walls on the inside of the cylinder. The air and oil are retained unconnected with the help of the piston rings, but they are not fool-proof so there will be some blending of air and oil which can be problematical.

On one hand, power tools need to be lubricated anyways so there is no harm in having some of the oil enter the air stream, but if you’re using air tools in woodworking or painting you will mess up the finish. Oil-free pumps have permanently lubricated bearings instead of an oil bath, and they don’t require the same kind of maintenance as oil-lubricated pumps do.