air compressor
air compressor

The air compressor is an important part of the industry, especially in workshops and factories SMEs. They allow to give power to different pneumatic tools such as the nailer and the impact keys , among others.

Being a machine whose versatility is no doubt, it is important to know it thoroughly to make the most of its capabilities and know how to face its preventive maintenance.

In this note we tell you its characteristics, its classification and some tricks and tips so you can take advantage of it and last for many years.

Ten things you need to know about air compressors

1. How are they classified?

The air compressors are classified according to two criteria: maximum pressure supplied to the tank outlet, and compression system used.

Classification by pressure

The compressors can be classified according to the pressure they offer at the outlet of the tank. There are three categories:

  • Low pressure: reach a maximum of 150 psi (10.55 kg / cm²).
  • Medium pressure: they are in the range of 150 psi (10.55 kg / cm²) to 1000 psi (70.3 kg / cm²).
  • High pressure: exceeds 1000 psi (70.3 kg / cm²).

Classification by compression technology


Lysholm screws, used in some screw compressors.

The compression is achieved, in some models, by a pair of special screws, called Lysholm. The air enters a chamber, the screws compress the air, pressurizing it and expelling it towards the tank, where it is stored.


Other models use two helicoidal rotors – one male and the other female – that mesh with great precision. Here we offer a video where you can see the operation of this mechanism.



Diagram of operation of an axial compressor.

They compress the air through both fixed and rotating vanes, and the air circulates parallel to its axis. These compressors allow to maintain a constant pressure at the outlet, so they are the most suitable for industrial applications of high demand. Their disadvantage is that they tend to be large, so they are not portable.

2. What criteria should I follow to choose the best air compressors?


There are several guiding criteria when choosing the best compressor that is suitable for the tasks to be carried out in the garage, the workshop or the SME.

Air flow

The first is to calculate the maximum air flow of all the tools that will be used simultaneously. This value is cumulative and you must add 25% of the sum; Thus, if we plan to use two toolsthat together require an air flow of 10 l / s, we will have to look for a compressor that ensures at least 12.5 l / s.

In summary: if the sum of the consumption of all the tools is Ft , look for a compressorwhose capacity ( Cc ) satisfies this simple equation:

Cc = Ft + 0.25 · Ft

3. What shapes can the compressed air tube have?

to. Vertical tube


The tube is arranged vertically. They are very popular in small workshops where there is not much space. Its disadvantage is that, having the center of gravity higher than in other models, it is necessary to keep it out of the way to prevent it from tipping over.

b. Horizontal tube


It is the most common. The cylinder is arranged horizontally, with the compressor on the top or on the side. They are almost always provided with wheels to ease transportation. Its center of gravity is low, so it is difficult to overturn them. Its disadvantage is that they take up more space than other models.

c. Flat cylindrical tube

The tube is of low height and width, so they occupy little space both in width and height. They are the most portable of the three models, although due to the dimensions of the tank, they do not have as much capacity.

4. Are there portable air compressors?

Yes, and there are many different models of portable compressor also mini compressors for airing up balls, car tires etc. Among them they differ mainly by the shape of the air tube; some are wide cylinders, others are long bottle-type tubes.

While they provide a limited amount of compressed air, their reduced size and weight make them ideal for carrying in the trunk of the car or in the basket of tools . Many of them even allow to connect to the 12V output of the car, making them particularly useful for field work, where electricity is not available at all.

5. Are there motor compressors with internal combustion engines?

Yes, although they are larger and are mainly intended for industrial applications . There are models with gasoline and naphtha engines; The latter (diesel engines) are semi-permanent, and require towing by a utility vehicle.

Its main use is road work (feed hammers and other pneumatic tools of large size).

6. What practical applications do air compressors have?

Pneumatic impact wrench; one of the many tools that can be used thanks to air compressors.

There are many tools and applications possible thanks to air compressors . The impact wrenches , saws type Dremel, airbrushes, the nail guns and simple to use compressed air cleaning methods are some examples .

In general the tools and accessories are divided into three large groups: those accessories that make direct use of air (compressed air guns, airbrushes), by means of pistons (nailers) and finally, those that use it to rotate a pneumatic motor (saws and hand winches).

7. What accessories can I use with air compressors?

As we saw before, there is a wide range of tools and accessories that can be connected to an air compressor . It is considered an accessory to any simple tool that uses compressed air directly.

Some examples (which can be seen in the photograph above) are air guns-used to blow pressurized air with different nozzles-and airbrushes, of which there are different models for each need. In the latter case, the Venturi tube principle is used to atomize the paint or the liquid contained in the tank attached.

The main use of the airbrush is to perform precise works of paint, but can also be used with other substances such as poisons (for fumigation), oil (to protect different pieces of steel and iron during metallurgical processes in a workshop or factory) and even powders as enamels for ceramics.

8. What should I keep in mind for daily use?

There are three key aspects that must be reviewed before using the air compressors .

to. Oil level

Every compressor has a small oil tank, which serves to lubricate the different parts of the compressor. Each model has its own measures, so it is safest to consult the manual to know how to measure the oil level and what is the appropriate level.

The time of use must also be taken into account; On average, the oil should be changed after exceeding 1000 hours of use.

b. Water level

The air contains moisture. When compressed, that moisture condenses and forms water, which is deposited at the bottom of the cylinder of compressed air. It is very important to purge this liquid every so often, to avoid it emulsifying with the oil and oxidizing or damaging the different moving parts of the compressor or the tools used.

Usually there is a small riffle or bobbin under the tubes, or on the side. When you open it, water will come out under pressure for a few moments. When only air comes out, it means that the purge is complete.

c. Cleaning the air filter

The third important factor is to verify that the air filter is clean. Consult the manual to find out where it is located, how you can verify it and how to replace it if necessary.

9. What should I avoid when using the compressor?

The air compressor needs to be cleaned and maintained periodically, both the engine and the tank and other static parts.

The tank, due to use, may suffer scratches in the paint. It is important to always keep your surface properly cleaned and covered with paint to avoid corrosion due to the different chemicals that may have been suspended in the air. Corrosion should be avoided and, if detected, should be treated immediately with a rust converter and then a new coat of paint.

The motor must remain clean and free of particles. The same can be said of compressor heat sinks, pressure gauges, and so on.

10. Storage

Care should be taken to store the compressor in a place free from dust, corrosive atmospheres, shavings and the passage of people, especially those outside the daily operation, children and pets or animals.

Finally, to properly store the air compressors , look for a place protected from the sun, moisture and corrosive elements. The ideal is to place them at the back of a garage if its use is homely, or in some corner of the factory that is away from the machines that give off chip or dust.

They should also be protected from the passage of people, especially those unrelated to the activity carried out, children and pets or animals.

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