This image is part of "Dare to compare air compressors" an article by Niff Ambrosino, general manager at Scales Industrial Technologies, West Patterson, N.J., that appeared in the January, 2008, edition of Plant Services.
The rotary-scroll compressor is a relatively new design. One of two identical intermeshing spirals or scrolls is stationary and the other oscillates in relation to the stationary scroll. The movement of the spirals forms air pockets of variable volume. As the moving scroll orbits within the fixed scroll, the air pockets diminish in size as they scroll spirally towards the center. (Animation courtesy of Air Squared, Inc.)