Editing Compressor (section)

====Scroll compressors====

[[File:Two moving spirals scroll pump.gif|thumb|right|Mechanism of a scroll pump]]
{{Main|Scroll compressor}}
A '''scroll compressor''', also known as '''scroll pump''' and '''scroll vacuum pump''', uses two interleaved spiral-like vanes to [[pump]] or compress [[fluid]]s such as [[liquids]] and [[gas]]es. The vane geometry may be [[involute]], [[archimedean spiral]], or hybrid curves.<ref>Tischer, J., Utter, R: "Scroll Machine Using Discharge Pressure For Axial Sealing," U.S. Patent 4522575, 1985.</ref><ref>Caillat, J., Weatherston, R., Bush, J: "Scroll-Type Machine With Axially Compliant Mounting," U.S. Patent 4767293, 1988.</ref><ref>Richardson, Jr., Hubert: "Scroll Compressor With Orbiting Scroll Member Biased By Oil Pressure," U.S. Patent 4875838, 1989.</ref> They operate more smoothly, quietly, and reliably than other types of compressors in the lower volume range.

Often, one of the scrolls is fixed, while the other orbits eccentrically without rotating, thereby trapping and pumping or compressing pockets of fluid between the scrolls.

Due to minimum clearance volume between the fixed scroll and the orbiting scroll, these compressors have a very high [[volumetric efficiency]].

These compressors are extensively used in air conditioning and refrigeration because they are lighter, smaller and have fewer moving parts than reciprocating compressors and they are also more reliable. They are more expensive though, so peltier coolers or rotary and reciprocating compressors may be used in applications where cost is the most important or one of the most important factors to consider when designing a refrigeration or air conditioning system.

This type of compressor was used as the [[G-Lader|supercharger]] on Volkswagen G60 and G40 engines in the early 1990s.

When compared with reciprocating and rolling piston compressors, scroll compressors are more reliable since they have fewer components and have a simpler structure, are more efficient since they have no clearance volume nor valves, and possess the advantages both of surging less and not vibrating so much. But, when compared with screw and centrifugal compressors, scroll compressors have lower efficiencies and smaller capacities.<ref name="autogenerated1"/>