How Does a Scroll Compressor Work?

How Does a Scroll Compressor Work?

A scroll compressor works by drawing vapor into crescent-shaped pockets between two interleaving scrolls, trapping the substance as the pockets decrease in size while circling inward. This process reduces the size of the compartments holding the vapor, which raises the vapor's pressure and temperature before it is discharged.

One of the scrolls is usually stationary and attached to the compressor body. The second scroll is mobile and mounted on a rotor shaft so that it can oscillate inside its housing in a path defined by the fixed scroll. The mobile scroll does not rotate, but moves in an orbital motion.

As it moves, it generates suction by pressing against the sides of the static scroll to create a series of gaps traveling between the two. This continuous motion draws vapor from the intake valve into the pockets, seals it there and forces it inward around the spirals toward the center.

Several pockets are compressed simultaneously for a smooth, continuous cycle. Fixed volumes of vapor are squeezed to an ever-increasing degree as they near the center of the compressor drum until the vapor is fully heated, compressed and then discharged.

The compressor compresses the discharge vapor to zero volume, eliminating any carryover of trapped discharge to achieve 100 percent volumetric efficiency. Its design allows it to operate more quietly and with less vibration than other compressors, and because it does not use pistons, it operates without re-expansion losses.