Gas flow through the compressor is continuous, so this reduces the tendency for gas pulsation that can generate noise. Typical designs usually run quieter than equivalent piston compressors. That can mean higher reliability, and they tend to have low maintenance requirements. For one, the units have few moving parts. Nonetheless, scroll compressors can typically generate relatively high pressures - 100 to 150 psi - in single-stage units.įor engineers, scroll compressors can offer a number of benefits. However, there are practical limits on the maximum amount of compression, mainly due to the size, shape, wall thickness and strength of the scrolls, and the size and geometry of the outlet port. The design of the discharge port determines the amount of internal compression, similar to that in a screw compressor. Finally, it reaches the center of the assembly where pressurized gas discharges through a port. Gas gets trapped in crescent-shaped pockets between the two scrolls, and continuous orbiting moves it steadily toward the center, reducing volume and causing compression. Movement creates suction that draws gas from the outer inlet openings. The drive motor moves the scroll body in an orbital fashion about the stationary scroll, but the scroll does not rotate. The moving scroll mounts on an eccentric crank offset from the center of the stationary one. They are bounded by a flat base and cover. In a typical design, the second scroll is rotated 180° with respect to the first, which lets the scrolls mesh. Each is a precisely machined or cast part in the shape of an involute spiral. The two main components are a stationary scroll and an identical moving scroll. Atlas Copco SF scroll compressors generate Class 0 air at pressures to 145 psi and flows to 86 cfm. The concept of a scroll compressor has been around for more than a century, but it took more-recent advances in manufacturing technology to make the product viable. Air (or other gas) is drawn in, trapped, reduced in volume and, finally, discharged at the outlet port. Scroll compressors are positive-displacement devices that work by internal compression.