How Does an Air Compressor Work

Ningthoujam Sandhyarani Jan 28, 2019
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In an air compressor, air is compressed by pulling in atmospheric air, reducing its volume and increasing its pressure. There are three major types, namely, reciprocating, rotary, and centrifugal compressor.
An air compressor is a versatile device used for supplying compressed air and/or power into a specific space. It is used for any purpose that requires air in an increased pressure, or we can say, air in a reduced volume.
It makes a vital mechanical device for the homeowners (refrigerators and air conditioners), jet engines, commercial businesses, refining industries, manufacturing industries, and automotive industries. In fact, air compressor has been used in the industries for more than 100 years.

Three Main Types

Air compressors are available in various types, which are designed to meet different requirements of the user. Each of the types may differ in the cooling method, compression stages, lubrication, and power source.

Reciprocating (Piston) Air Compressor

A reciprocating air compressor makes use of piston(s) to compress air and store it in a storage tank. Based on the number of compression stages, reciprocating compressor can be a single-stage or double-stage configuration.
In the single-stage unit, only one piston is used to compress air, whereas there are two pistons for air compression in the double-stage air compressor.

Rotary Air Compressor

This one is similar to the positive displacement configuration of a reciprocating compressor. Over here, two spinning helical screws or rotors are involved for compressing air (instead of using pistons), hence the name. As the screws mesh towards each other, air is compressed and pushed inside a storage tank.

Centrifugal Air Compressor

A centrifugal air compressor is also called a dynamic compressor. It is applicable when the demand for compressed air is high. In this unit, a high-speed rotating impeller increases velocity of air, which is directed towards a diffuser that converts the velocity of air into pressure. A centrifugal air compressor requires more energy to operate.

Working Mechanism

In an air compressor, there are two major parts - a compressing system and a power source. The compressing mechanism can be a piston, rotating impeller, or vane depending upon which type of compressor you are referring to.
As for the power, it is supplied by an electric motor or other energy sources. The compressing mechanism, as the name suggests, helps in compressing atmospheric air by using energy from the power source.
The basic working principle of an air compressor is to compress atmospheric air, which is then used as per the requirements. In the process, atmospheric air is drawn in through an intake valve; more and more air is pulled inside a limited space mechanically by means of piston, impeller, or vane.
Since the amount of pulled atmospheric air is increased in the receiver or storage tank, volume is reduced and pressure is raised automatically. In simpler terms, free or atmospheric air is compressed after reducing its volume and at the same time, increasing its pressure.
There is a pressure setting knob that can be manipulated as per the demands of the operator. When pressure in the receiver or tank increases to the maximum level, the pressure switch is shut off and intake of air in the compressor is stopped. Contrary to this, when the compressed air is used, the pressure inside the compressor falls.
As a consequence, the pressure drops to a low setting, and the pressure switch is turned on, thus allowing atmospheric air to enter the unit. This way, the cycle of taking air inside the unit and removing compressed air continues in an air compressor.
As per your requirement and budget, you can consult with a reliable manufacturer about the suitable air compressors. Always purchase a durable model that is easy and safe to operate. If you are purchasing a used air compressor, make sure you check the performance, machine configuration, operation type, price, and operating cost of the unit.
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