Compressed air has many uses in the industry. Compressing air is an effective means of storing energy and transporting it over large distances.
Some of the applications of are:
As a source of energy to drive machines and pneumatic tools, which are smaller than electrically driven tools.
- In Shot blasting applications
- In Spray painting
- In control systems. compressed air is widely used in the petrochemical industry where electric power cannot be used due to the risk of fire.
- In Braking systems in trains.
- In Refrigeration
- In spray cans such as those used in perfumes and other sprays.
- In cleaning
Pneumatic tools are tools which are driven by air. In these tools, compressed air from a cylinder is made to pass through a control valve which is operated by the user. The air is then passed through a small turbine which generates rotary motion. This rotary motion is used to drive a shaft.
This rotary motion can be used for drilling or grinding purposes. The air is then drained through an outlet.
It is easily available
Tools can be smaller than electric tools.
These tools can develop high torque
They can be used in environments where there is a risk of fire
They are not affected by temperature
They are clean and do not leave any residue
It can be guided easily through small tubes wherever required.
They are noisy
Leakages occur frequently
Air should be dried properly otherwise there can be condensation.
Positive Displacment Compressors
Positive displacement compressors suck a specific quantity of air into a cylinder. The piston then compresses it. The output of a positive displacement compressor is always.
Examples of positive displacement compressors are Reciprocating Piston compressors, Rotary Screw compressors, Scroll compressors and Rotary Vane compressors.
Positive displacement compressors can build very high pressures. The downsides are high noise, lesser efficiency, leakages from the seals and frequent maintenance.
Single and Double acting compressors
In single acting compressors, air is drawn and compressed on only one side of the piston. When the piston moves down, the suction valve opens and air enters the cylinder. When the piston moves up, at the end of the compression, the discharge valve opens and the compressed gas is released.
The other side of the piston is connected to the crankshaft.
In a double acting compressor, air is drawn and compressed on both sides of the piston. The piston is operated by a connecting rod through an airtight seal. There are compression chambers on both sides of the piston and a set of suction and discharge valves..
Double acting compressors have higher efficiency. However, they are expensive to manufacture. They are usually water cooled.