Air Compressor - Basic

Air Compressor is a device which is convert energy (like electrical motor, diesel engine or gasoline engine) by storing pressurized air into potential energy. Working method on an air compressor is store the air in tank by more forces and shut off after reaching its higher pressure limit. This pressurized air used in various work by a pneumatic system, when the tank pressure reaches a certain limit, compressor start again to fill the air tank. Electrical and Air pressure are the two power source which are mostly use in many industries all over the world.

Air Compressor Types

There are several types of air compressors according to the design and principle of operation:

Reciprocating compressors: Using a reciprocating piston which is moved up and down by a rotating crankshaft, like a car engine. Single Stage and Two Stage Reciprocating compressors are commonly used.

Rotary Screw air compressors: Using two meshed screw drives that constantly rotate to force air to down the shaft from the larger, from least-compressed grooves to more compressed grooves. Mainly used in Industrial purposes.

Rotary Vane Compressors: A rotor with a number of spring-loaded blades are using here. This rotor is set inside a cylinder, spins to move air from the larger area of the cylinder into the smaller side. By the movement of this rotor from large area to small area compresses the air.

There are other types of compressor, but these are the very common.

How Reciprocating Air Compressors Work?

All air compressors working principle are same, moving air from a larger area to a smaller area. Here we discuses about Reciprocating Air Compressor.

These types of compressor working like a car engine. An electric motor (sometimes a gas engine) rotates a crankshaft that moves the connecting rod, which causes the piston to move up and down inside the compression chamber. 

On the down stroke, the inlet valve opens and air comes from the outside. Piston compressors have a weakness from dirt, so an air filter is using to remove the dirt from air. 

On the upstroke, the inlet valve shut-off, and the unload valve opens, passing the compressed air to the air tank. When the piston moves down, this discharge valve remains close. Air come into compression chamber, trapping the compressed air in the storage tank and the inlet valve opens, repeating the cycle. 

Important Parts of an Air Compressor

Pressure Switches

The pressure switches use for measuring the pressure amount which is building inside the tank and control the motor. This pressure switch use to ensure motor run at low air pressure and cut-off at high air pressure. It is a safety device to ensuring the safety of device as well as user. When motor start, air goes to the tank and a pressure is building up. At a set pressure point, pressure switch give a high pressure signal and switch off the motor. After some use of air from the tank, pressure is going low and a start signal goes to the motor to start.

This difference between the low pressure point and the high pressure point is called the “pressure differential.”

Overload Valve

Overload valve is another safety device to protect the air storage tank from explosion. Every air compressor’ tanks must have a certain standards. An overload valve’s parameter adjust by tanks standard to control the over pressure.

Air Regulator

There are two gauges used in air compressor, one in air tank for showing the pressure of the tank. Another one for measuring how much air flowing out, this gauge is regulated by a knob to adjust air pressure how much you need.

Drain Valve

A drain valve is using in air tank to remove water component from compressed air. When air is compressed, air is going lose its temperature and some moisture is gain in the air.

Terms and Specifications for Air Compressor

Now talk about some terms and specification to understand the nameplate of an air compressor.

Horsepower: This terms using mainly for motor or engine which is run the air compressor. It may be written in horsepower or kilowatt (KW). This term is for showing how much power consummated by a compressor.

Pressure: Low and high pressure range is given by this term. The unit of this pressure is given in Pounds per Square Inch or PSI.

Power Source: As run by electric power, air compressors need 3 phase or single phase electrical power. For large volume air compressor 3 phase motor is using. Small compressor runs by single phase motor.

Air Tank: This specification is varying for users to user. Air tank will depends on how much air you need for your work.