A typical rotary screw air flow compressor has two interlocking helical rotors contained in a housing. Air will come in through a valve, typically called the inlet valve and can be taken into the space between your rotors. As the screws convert, they reduce the level of the air, hence increasing the pressure.
The heart of an air compressor may be the screw element which can be called air-end. The air-end can be the most important component of any screw-type compressor. It’s that section of the Screw Air Compressor china machine where the actual compression occurs. It is the cardiovascular of the rotary screw air flow compressor.
A Rotary Screw Atmosphere Compressor is a compressor that runs on the rotary-type positive displacement mechanism, called a rotary screw, air-end. 
… Rotary Screw Compressors also make use of two inter-twined helical formed screws, known as rotors, to compress the air flow.