Compressors serve to compress and convey gaseous media. Piston, rotary and screw compressors are typical designs. Screw compressors, for example, reduce the volume of the air stream through the rotational movement of helical rotors, thereby increasing pressure and temperature. They are used in automotive engineering, refrigeration and air-conditioning, refrigeration engineering, process plant engineering and generation of atmospheric pressure. Turbochargers, also known as exhaust gas turbochargers, use the pressure and the kinetic energy of the exhaust gas stream to increase the performance of motor vehicles. They consist of a shaft with compressor wheel and turbine wheel. Through the air inlet of the turbine housing, the exhaust gases reach the turbine wheel and set it in motion. The rotary movement of the turbine wheel corresponds to that of the compressor wheel, which now aspirates and compresses fresh air in order to convey it to the engine.