Sale of semi-hermetic compressors

In principle we have to take into account that a compressor is a machine built to increase the pressure of compressible fluid such as gases and vapors to move it through mechanical compression. They are responsible for reliably raising the pressure of a basic gas flow to be used directly or stored in suitable tanks.

Types of compressors

Industrial compressors can be divided into two large groups:

Positive displacement type compressors

Among which we have:

  • The piston compressors where the air is sucked into a cylinder by the action of a piston driven in turn by a connecting rod and a crankshaft. When performing the opposite movement, the same piston compresses the air inside the cylinder.
  • The screw compressors, these are based on the displacement of air through the chambers that is created with the simultaneous rotation and in the opposite direction of the screws.
  • The vane compressors consist of the installation of a rotor with floating blades inside a casing
  • Rotary piston compressors, is based on the rotation of the two lobe rotors inside the casing that rotate synchronously and in the opposite direction, forming between them a chamber into which the the air.
  • Scroll Compressors assume orbital scrolling. Compression is done by volume reduction. It is made up of two spiral-shaped rotors.

Dynamic type compressors

These compressors are divided into:

  • Radial centrifugal compressors, are the traditional compressors. In these units, the air enters the central area of ​​the rotor guided by the suction hood.
  • Centrifugal axial compressors, in this case the air circulates parallel to the axis. They are made up of several rotors and between each of them are the stators.

Cabin models

Now, in the case of compressors in relation to refrigeration and air conditioning, they are manufactured differently depending on the type of cabin, so we have:

Hermetic motor compressor

It implies that its components (its coils, its mechanisms, pistons) are inside a casing that we cannot open. If the diagnosis that is carried out assumes that one of these components is failing, then the entire hermetic compressor must be changed, that is, it is not repaired, but replaced. It is generally used in small and low-power installations, since they have a lower cost and take up less space inside the unit. The refrigeration is given directly by the refrigerant itself and does not require transmissions between the engine and the compressor.

Semi-hermetic motor compressor

In this case, it has a separate compartment where its electric motor is located and another compression compartment, that is, its compression mechanism is separate. Therefore, we can have access to any of its chambers, the pistons, the connecting rods, the covers... and in the event of a fault, it can be repaired in this type of compressor. They are usually used in medium power installations.

Open compressors

They are compressors that are driven by external motors, whether electric or mechanical motors and, as in the previous case, can be repaired.

Semi-hermetic compressor operation

How does a compressor work? The compressor has an inlet called suction and an outlet, ie discharge. The refrigerant enters in the gas state at low pressure. Inside the system, its pressure and temperature will rise and then it will be sent to the condenser.

Semi-hermetic refrigeration compressor

Within the refrigeration compressors, we have according to their operation / Technology:

Reciprocating piston compressor

It is a compressor that contains one or more cylinders with pistons driven by the engine. Air is sucked into the cylinder and compressed, and then the compressed air passes through the aftercooler to the air reservoir.

Rolling piston rotary compressor

In this case, air rushes through the inlet port and is trapped between the lobes and the stator. As a consequence of the continuous rotation, the point gear begins to move around the rotors, reducing the space occupied by the air, thus increasing its pressure.

Rotary screw compressor

The screw compressor compresses the air in the space between the two rotors, which, as we mentioned above, rotate in the opposite direction and simultaneously. It basically works in two ways: with liquid injection or without it.

Scroll Compressor

It is a positive displacement compressor. Thanks to the design of the spiral rotor, it generates a continuous flow of compressed air in several stages and does not require oil lubrication. Said compression is carried out by volume reduction.

Centrifugal compressor or turbocharger

This is the name given to the centrifugal compressor that can be axial or radial. In the case of the axial compressor, it is dynamic, that is, the sucked air circulates parallel to the axis. These compressors are made up of several rotors.

Oil change and filter cleaning in semi-hermetic compressors

How to clean a compressor filter?

To clean the compressor filter, you need to shake it by hand. It's that simple. Since in this way we ensure that enough air enters the compressor. Ideally, you should clean the filter periodically to ensure that the compressor is working properly.

How do you change the oil of a compressor?

Use a recovery tank. Open the drain cock and let the oil flow into the container. Remember to dispose of the oil in the corresponding garbage container to take care of the environment. Close the drain valve. Open the oil tap and fill carefully with the funnel.


As for the price, we can find a great variety clearly depending on the model and the type of power we need. We have, for example, the case of the HG12P/90-4 Bock compressor that costs €1,003.00 without VAT.

Buy semi-hermetic compressor

When buying we recommend that you take a good look at the types of existing models, you will see on our page that there is a wide variety of them. If you need information, do not hesitate to contact us. The quality is guaranteed.

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