A typical rotary screw air compressor has two interlocking helical rotors contained in a housing. Air will come in through a valve, typically known as the inlet valve and is taken in to the space between your rotors. As the screws turn, they reduce the level of the air, thus increasing the pressure.
The cardiovascular of an air compressor may be 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 cardiovascular of the rotary screw air compressor.
A Rotary Screw Atmosphere Compressor is a compressor that runs on the rotary-type positive displacement system, called a rotary screw, air-end. ... Rotary Screw Compressors also make use of two inter-twined helical designed screws, known as rotors, to compress the atmosphere.