All About Air Compressors

The Demand and supply for the compressors are never-ending, but a huge area to be employed and mark the position amongst the main component.

The Compressors these days used by the designers and the manufacturers in Automobile Industry are equipped with high-end technology and don’t leave any chance for their outstanding performances.

Though the basic functionality of any compressor remains the same their application is increasing exponentially.

What is a Compressor??

So basically, The Compressors are mechanical devices/components that are used to increase the pressure by reducing the volume of a gas.

An air Compressor can be classified as a particular type of gas compressor.

The Compressors are similar to the pumps with the difference lying that compressors, compress the gases like the air that are compressible and increases its pressure while decreasing its volume, whereas pumps do the same with liquid.

Types of Compressors

There are 2 main types of compressors that are further subcategorized under specific types.

Positive Displacements Compressors

Dynamic Compressors

Positive Displacements Compressors

These type of compressors are that compresses the air through some mechanical linkage mechanism, such as piston arrangement as in thermodynamics piston displacement is considered as to be a positive displacement.

Under Positive Displacement Compressors there are subcategorized compressors:-

Reciprocating Compressors

Reciprocating types of compressors use pistons that are powered by the crankshafts, can be single staged or multistaged which means single-stage meaning only a single area where the compression takes place, whereas in multi-stage the air is compressed with increasing stages.

The reciprocation of piston causing it to move back and forth increases the pressure.

The positive reciprocating compressors can be powered by electric motors or internal combustion engines.

Single staged compressors are used in automobiles, air conditioners and multistage are used in industrial applications.

Single Stage with Single Cylinder and Dual Cylinder

In Single Stage Single Cylinder, there is 1 suction department, a discharge area, and a compression. The single-stage dual cylinder consists of 2 suction departments, a discharge area, and compression and produces more gas pressures.

Double Acting Compressors

Double Acting Compressors are more efficient and produce double the capacity as they compress the air on both sides that is while stroking up and stroke down.

In Diaphragm types of Air Compressors, there is a membrane that is linked to a mechanical linkage or a crankshaft that forces the membrane to reciprocate back and forth thus pressurizing the gas and decreasing the volume.

If a metal base diaphragm is used it may not be able to pressurize to a high magnitude as metals cannot bend and displace to large length but the stiffness of any metal allows it to pump at high pressures.

The opposite is the case if using other flexible materials like rubber or silicon.

2. Rotary Compressors

Rotary Compressors

There are various types of Rotary Compressors that function on the same concept that air is being compressed through the rotation of some mechanical components in 1 way or the other.

Lobe type air compressors usually have 2 rotors connected externally oriented differently. One rotor is

connected to the drive and the other rotor is connected to the gear set.

These rotors consist of the lobes ie epicycloid, hypocycloid or involute profiles (2–3) depending and then traps the air through the inlet area, positively compresses the air decreasing its volume.

There is a very minimal difference between the lobes to prevent wear but responsible for a decrease in the efficiency and effectiveness as air can pass through.

Screw type air compressors are the backbone of the compressor market today. Inside the screw-type compressors there are 2 screws situated very close to each other that rotates in opposite directions.

The air comes for the inlet, transverse along the length between the screws rotating against each other, and the air gets trapped inside the screws and gradually gets compressed.

So the output air is heavily compressed.

Scroll types air Compressors are similar to the Screw type Air Compressors but the difference being that they have spiral type rotating parts and one of which remains stationary.

Air comes from the inlet, gets trapped while rotating, and gets pulled towards the center of the spirals and tighter and tighter circles of the spirals and thus compressing the air.

This system uses a set of vanes that are slightly offset from the center and thus the air is trapped at that particular edge of the circle and thus the vane when rotated compresses the air tighter and tighter trapped at the one side of the circle.

This system requires minimal effort and easy to maintain but wears comparatively fast over the years.

Dynamic Compressors

Dynamics Compressors are turbocompressors that depend upon the inertia and the momentum of the liquid.

The gas is impacted on the impeller, which rotates due to the inertia and thus used to pressurize.

There are 2 types of Dynamic Compressors ie

Centrifugal Compressors
Axial Compressors

Centrifugal Compressors

The Centrifugal compresses marks 70–80% of the dynamic compressor market.

The main concept of their action is that they use the velocity to be impacted on a stream of gases and the energy created is used for pressure.

In Centrifugal compressors the process can also be carried out in a single-stage or multi-stage where each stage takes advantage of an impeller (a rotating disk) and diffuser (a stationary element).

Both single and multistage machines are generally made up of standardized components. However, the multistage helps in improving the compression ratio because centrifugal compressors generally have lower compression ratios as compared to the displacement compressors.

Axial Compressors

Axial Compressors are mainly employed where compact design or high flow rates (large flow volumes) is demanded.

These compressors have a pressure range between low to medium and their application in jet engines, natural gas pumping stations, chemical plants, and large gas turbine engines.

When it comes to how this compressor works, gas is compressed with the use of an array of airfoils which are arranged in rows arrangement.

The airfoils can exist as pairs, where one of the set is a rotating airfoil known as the blade or rotor and the other is a stationary airfoil also known as stators or vanes.

While the rotating airfoil accelerates the fluid, the stationary airfoil decelerates and also redirects its direction in preparation for the rotor blades of the next stage.

Conclusion

Thus, compressors have a huge classification, huge applications, and huge demand and supply department and serve as the main entity to almost every system

Originally published at https://www.carengineered.com on July 21, 2020.