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1. (WO2018041556) VACUUM PUMP SCREW ROTOR

Pub. No.:    WO/2018/041556    International Application No.:    PCT/EP2017/070065
Publication Date: Fri Mar 09 00:59:59 CET 2018 International Filing Date: Wed Aug 09 01:59:59 CEST 2017
IPC: F04C 18/18
Applicants: LEYBOLD GMBH
Inventors: DREIFERT, Thomas
SCHILLER, Dirk
GIEBMANNS, Wolfgang
MÜLLER, Roland
Title: VACUUM PUMP SCREW ROTOR
Abstract:
The invention relates to a vacuum pump screw rotor, comprising at least two helical displacement elements (10, 12) on a rotor shaft. The at least two displacement elements (10, 12) have different slopes, but the slopes of each displacement element are constant. Furthermore, the displacement elements each have a helical recess, each having a contour that remains the same over its entire length. Hereby, a suction-side displacement element (10) has a recess having an asymmetrical contour, and a pressure-side displacement element (12) has a recess having a symmetrical contour.