There is a current toward increased use of the rotary-type compressor due to
technological advances, which have produced stronger materials and better
manufacturing process. The following figure shows a cutaway view of a single-stage
screw type compressor. Precise positioning of the screw is essential for its
performance. Oil provides a seal between the rotating screws as well as lubricating
the parts and cooling the air. The oil is then separated from the air before it enters the
system.