Most shops have an air compressor lying around somewhere. These helpful devices use compressed air to power some of the most common tools in the workshop, including drills, grinders, nail guns, sanders, spray guns, and even staplers.
But how do air compressors actually work? And can they be repaired in-house if they break down, or do you need to pay extra for specially trained technicians to make the repairs?
Air Pressure and Air Volume
There are many different types of air compressors, including one-cylinder, two-cylinder, rotary screw compressors, and more. But they all pretty much work according to the same principle.
Compressing air is essentially a two-stage process in which 1.) Air pressure goes up, and 2.) air volume goes down. Typically, this effect is created by use of a reciprocating piston.
While moving back and forth, the piston essentially creates a vacuum. When the piston retracts, the area in front fills up with air. When the piston extends, this same air is compressed. It also is pushed through the discharge valve, usually into a reinforced air tank that is strong enough to hold pressurized air.
Reciprocating piston air compressors, which are the most common type used today, have five major components: The crankshaft, connecting rod, cylinder, piston head, and valve head.
Powering Up an Air Compressor
In most cases, either a gas engine or an electric motor is used to power an air compressor.
On one end of the cylinder are the inlet and discharge valves. These devices, which are shaped like metal flaps, can be found at opposite sides of the cylinder’s top part. Air is sucked into the cylinder, where the piston compresses it before releasing it through the discharge valve.
The most common type of air compressors used by tradesmen run on positive displacement. This is when air is compressed within compartments, each of which reduces the volume of the air, or the amount of space it takes up. Most have air tanks, although some very small and less powerful air compressors are composed basically of a pump and a motor.
The air tank stores air within specific ranges of pressure until it’s needed to power equipment. As it the pressurized air is released, it can power pneumatic tools connected to its supply lines. Throughout this process, the air compressor’s motor will turn on and off in order to maintain the proper pressure inside the tank.
From air conditioning units to pneumatic tools and more, air compressors are one of the most widely used types of machinery in industry.