Air compressors are generally used to compress air into a holding tank so that it can be used as a source of potential energy. In other situations, they are used just like pumps for inflating things like bouncy castles and paddling pools. Diesel, electric and petrol-driven air compressors are available for various industrial and domestic uses, many of the systems being marketed according to how efficiently they run. Kaeser air compressors, for example, are almost entirely focussed on reducing energy bills, but they still operate in much the same way as other types of air compressors. How is it that an air compressor is able to function efficiently?
Reciprocating Piston Technology
By harnessing the power of simple technology like a piston, air compressors are able to operate without needing a very large engine. When air is compressed, the volume of space that it takes up decreases. However, there is a corresponding increase in pressure, which means that energy must be used to keep on squeezing more and more air into a finite amount of space. Modern air compressors overcome this increasingly difficult workload by using what is known as a reciprocating piston. These types of pistons utilise the unwanted pressure increase to push the piston head back to its original position, ready for its next compression cycle. Anyone familiar with the piston technology used in an internal combustion engine will be aware of how this simple idea works in practice.
Converting Rotational Force
Since many engine types generate rotational force, this needs to be converted to a backwards-and-forwards motion for the piston's movements to work efficiently in an air compressor. Therefore, every air compressor using a piston to push air from one place to another requires a crankshaft, which will connect to the piston head, usually via a rod of some sort. The rotational force of the motor is now converted to the back-and-forth motion needed for the piston to approach and then retract from the air compressor's valve head.
When an air compressor's piston pushes up and into a valve head, it will force the air that is in it through a discharge valve and into a storage chamber, such as an air tank. The pressure within then forces this valve shut at the height of the piston's extension. As the piston moves back, another valve opens. This time it is referred to as a suction valve. With the valve head devoid of air, so its low pressure sucks new air in. As the piston returns to a forward motion, the new air is pushed through the valve head and past the discharge valve once more. The process simply continues until the air compressor is switched off.