The heart of an air compressor is the screw element which is also called air-end. The air-end is the most important part of any screw-type compressor. It’s that part of the machine where the actual compression takes place. It is the heart of the rotary screw air compressor.
They are constant flow (volume) with variable pressure compressors. Which mean that at a given speed (rpm), they always supply the same amount of air (in liters per second for example), but can do so at different pressures.
Why are they so popular? Since it’s a continuous process (as opposed to reciprocating piston compressors) they supply a steady, non-pulsating air flow, with minimum vibrations and maintenance and maximum lifetime.
How does an air-end work? Inside the compressor element are two screws that turn in opposite directions. The rotary screw compressor is a “positive displacement” compressor, which means that the air is physically squeezed together by an external force (like piston and scroll compressors).
In the case of the rotary screw, the air gets trapped between the two rotors. The rotors have a special design for optimal efficiency and performance. One rotor is the “male” and the other is the “female”. The air gets sucked in on one side (cold, low-pressure), and gets trapped between the rotors, and then is discharged out the other side (hot, high pressure). This compression requires power, which is usually supplied by a large electro motor.
There are two basic types of screw compressors: oil-injected and oil-free. Oil injected rotary screw compressors are the most common, since they are the cheaper of the two. Oil-free screw compressors are used in applications where the compressed air must be 100% oil free, like for food processing and chemical plants.
They can operate 24/7, 365 days a year. The normal lifespan of a screw element is about 40.000 running hours, before a complete overhaul is necessary. That's when the folks at www.oemair.com come in. You can send in your air-end to be rebuilt to original specs and they offer a guarantee that is the best in the business. To learn more about this service, visit http://oemaircompressor.com/aircompressorairendrebuilding.aspx.
Rebuilding an air-end can save you thousands of dollars. Air Compressors are expensive and it doesn't make sense to get a new one when the air-end is at the end of its service life. Industrial Air-end rebuilding just makes sense (and dollars).