Air compressors are an essential part of industries. These are powered by off-highway diesel engines, or even by electricity. It is quite fascinating how we are surrounded by air and the part it plays in our daily lives. To understand the significance of air compressors, we must first explore the layers of our atmosphere and the crucial role air plays at different altitudes.
Our physical existence is surrounded by spheres of gases. If you sit inside a rocket and take a trajectory towards space you will be traveling into the Troposphere at around 10 kilometers, Stratosphere at around 50 kilometers, Mesosphere at around 85 kilometers, Thermosphere at around 700 kilometers, Exosphere at around 10,000 kilometers, and finally into the vacuum of space.
In each of these layers, the air pressure decreases momentarily, acting as a layer of defense against harmful UV rays and sustaining the ecosystem of our atmosphere.
Today, apart from supporting life on Earth, air is an element found with infinite opportunities to generate power. Its composition of different elements such as hydrogen has been found as the future fuel for Earth.
A compressed version of air when stored in a unit, can be utilised to power pneumatic tools. Pneumatic tools are new-age tools for construction, agriculture, automotive, and countless other industries. They function on high-pressure compressed air, sourced from an air compressor tank.
There are two main variants of air compressors:
Positive Displacement Compressors
It inhales fresh air from the atmosphere into an air chamber, where its volume is reduced with mechanical force, increasing its pressure. This machine applying mechanical force is termed as ‘air compressor’, from where the air travels to a tank assembled below it and this phenomenon is known as Positive Displacement.
Currently, there are three different types of positive displacement compressors:
Reciprocating Air Compressors
Inlet
The air flows from the outer atmosphere into the compression chamber through a valve.
Compression
A single piston with a cyclic movement, travels downwards during the inlet of air in the chamber and moves upwards compressing the air volume.
Outlet
As the piston repeats its cycle, the high-pressure air exits the chamber through an outlet valve, flowing straight into the assembled tank.
Rotary Vane Air Compressors
Inlet
The inlet valve opens to the largest chamber, the rotating vanes carry the air towards the outlet.
Compression
The vanes are arranged on an off-centred drive shaft, they compress and retract as they accelerate in rotation. The reduction in chamber size towards the outlet causes compression.
Outlet
Compressed air exits from the smallest chamber.
Screw Air Compressors
Inlet
The air is inhaled into an enlarging chamber of two spiral rotors.
Compression
The rotor teeth meshed together when performing cyclical rotation create a chamber with the casing wall. The rotors transfer gas towards discharge compressing by shrinking the chamber.
Outlet
Compressed air is discharged from the nozzle.
The reciprocating air compressor ideally has a single cylindrical unit decreasing the volume of air and increasing its pressure. Its typical compression ratio is 5:1 delivering a pressure output of 50-75 PSI. A single piston raises the temperature too high, making the process less efficient and susceptible to hazards if it comes in contact with any hydrocarbons.
To avoid hazards and continue generating high-pressured air, manufacturers redesigned the compressor with a double-stage and multi-staged compression unit. In each stage, the air is compressed and transported to another stage through a cooling channel. In the next stage, the air pressure is increased again and transferred into the tank. In a multi-stage compressor, the cycle is repeated depending on the number of compressors.
A six or seven-stage compression system can provide high-pressured air of 2500 PSI.
Dynamic Air Compressors
By converting kinetic energy to pressure air, dynamic air compressors are innovative in design and efficient at compressing air.
A dynamic air compressor is designed in two modules:
Centrifugal Air Compressor
Inlet
The air enters into a compressor housing through an inlet and accelerates towards the outlet.
Compression
To reach the outlet, air travels across rotating impellers that increase its velocity and diffusers that decrease it.
Outlet
The air exits the housing through an outlet.
Axial Air Compressor
Inlet
From the outer atmosphere, the air enters into the axial chamber in motion.
Compression
The structure of an air-foiled shaped rotor, with multiple blades progressively increases the air pressure. Each rotating blade is succeeded with a stationary blade that compresses the air.
Outlet
The compressed air exits through the outlet valve.
Myth vs. fact about air compressors
An air compressor is of no understanding and use for the common man.
High-pressure air is used to fill bottles with drinks and liquids we use in our day-to-day lives, to fill packaged food we eat, and the industries we work in.
Understanding how things work can help you solve problems or even better, guide you towards creating something innovative.
Reconditioning
An air compressor is powered by a diesel engine. An unmaintained diesel engine always increases the chance of reconditioning it.
Here are a few things indicating reconditioning:
- Absence of routine check-ups
- Unmaintained fluid and oil levels
- Vibration within element bearings
- Metal fragments contaminated by oil
- Failure of cooler
Reconditioning your diesel engine air compressor can raise its efficiency to its original potential. But before you reuse it ensure that it meets the industrial standards and is safe to use. Along with this, if the compressor is powered by a diesel engine then servicing the engine at regular intervals is recommended to ensure optimal working of the air compressor. When it comes to diesel engines, MVDE is one of the leading diesel engine manufacturers in India. Their products are extensively used in several applications like construction, agriculture, marine, and several others.
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